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ORNL-2474MOLTEN-SALT REACTOR PROGRAM

QUARTERLY PROGRESS REPORTFor Period Ending January 31, 1958

SUMMARY 1

PART 1. REACTOR DESIGN STUDIES

1.1. REACTOR DESIGN 9Study Layouts of Reactor System 9Nuclear Calculations 12

Univac-Ocusol Reactor Calculations 12Oracle Calculations 14IBM-704 Codes 15

Fuel Fill-and-Drain System Design 15Design of a Hydrostatic Bearing for a Molten Salt Pump Impeller 16

1.2. COMPONENT DEVELOPMENT AND TESTING 18Fuel Pump Design and Development 18

Pump Design Studies 18Development Tests of Salt-Lubricated Bearings 18Development Tests of Mechanical Shaft Seals 19Development Tests of Oil-Lubricated Bearings 20Irradiation and Endurance Tests of Bearings and Seals 20

Development of Techniques for Remote Maintenance of the Reactor System 20Mechanical Joint Development 20Remote Manipulation Techniques 24Heater-Insulation Units for Remote Application 25Maintenance Demonstration Facility 26

Heat Exchanger Development 27Design, Construction, and Operation of Materials Testing Loops 27

Forced-Circulation Loops 27In-Pile Loops 32

1.3. ENGINEERING RESEARCH 35Hydrodynamic Studies of MSR Core 35Physical Property Measurements 37Molten Salt Heat Transfer Studies 37

1.4. ADVANCED REACTOR STUDIES 41A Molten Salt Natural-Convection Reactor 41

Salt-Cooled Heat Exchangers 42Helium-Cooled Heat Exchangers for Steam Cycle 42Helium-Cooled Heat Exchanger for Gas-Turbine Cycle 43Comparison of the Various Cooling Systems 44Comparison of Natural-Convection System with Forced-Convection System 44

High-Flux Reactors 44

PART 2. MATERIALS STUDIES

2.1. METALLURGY 51Dynamic Corrosion Studies 51

Thorium-Bearing Salts in Thermal-Convection Loops 51Uranium-Bearing Salts and Coolant Salts in Thermal-Convection Loops 52Results of Examination of Samples Removed from Forced-Circulation Loop CPR 54

General Corrosion Studies 54Effect of Carburization on Reactor Structural Materials 54Corrosion of Brazing Alloys by Fuel Salts 59Corrosion of INOR-8 Welds by NaK and by Fuel Salts 60

Physical Properties of INOR-8 62Mechanical Properties of INOR-8 63Welding and Brazing Studies 64

Metal Seals for Remote-Disconnect Flanged Joints 64Welding of INOR-8 Tubing 65Evaluation Tests for Welds 67Examination of INOR-8 Forced-Circulation Loop That Failed During Initial Heating 71Fabrication of Test Components 73

Development of Nondestructive Testing Techniques 75Evaluation of INOR-8 Tubing 75Cladding Thickness Measurements and Bond Inspections 77

Inspection Results 77Material Inspection 77Weld Inspection 78Failure Analyses 78

2.2. RADIATION DAMAGE 79In-Pile Thermal-Convection Loop Tests 79In-Pile Static Capsule Tests 80

2.3. CHEMISTRY 81Phase Equilibrium Studies 81

Systems Containing UF4 and/or ThF4 81Solubility and Stability of PuF3 in Molten Fluorides 88

Fused Chlorides as Secondary Heat Transfer Fluids 90Vapor Pressures of LiF-BeF2 Mixtures 91Fuel Reprocessing 91

Solubility of Noble Gases in Molten Fluoride Mixtures 91Solubility of HF in Molten Fluorides 93Solubilities of Fission-Product Fluorides 94Order of Oxide Precipitation in Fluoride Salt Melts 97Chemical Reactions of Oxides with Fluorides in LiF-KF 99Lithium Recovery from NaF-KF-LiF Melts 101

Chemistry of the Corrosion Process 105Activity Coefficients of CrF2 in NaF-ZrF4 105Solubility of FeF2 in LiF-BeF2 107Use of 51Cr to Study Chromium Migration in Polythermal Inconel-Molten Salt Systems 107Activity of Nickel in Nickel-Molybdenum Alloys 111

Production of Purified Mixtures 113Preparation of Pure Fluorides 113Small-Scale Purification Operations 113Preparation of Material for In-Pile Loop 113Transfer and Service Operations 113


QUARTERLY PROGRESS REPORTFor Period Ending October 31, 1958

SUMMARY iii


1.1. CONCEPTUAL DESIGN STUDIES AND NUCLEAR CALCULATIONS 3Interim Design Reactor 3

Fuel Fill-and-Drain System 3Fuel-to-Steam Heat Transfer 3Comparative Costs of Several Systems 4

Experimental Reactor Calculations 6Nuclear Calculations 6

Nuclear Characteristics of Homogeneous, Two-Region, Molten-Fluoride-SaltReactors Fueled with U233 6Blanket Fissions in the Reference Design Reactor 9Comparison of Ocusol and Compone Calculations 10Heterogeneous Reactors 11Gamma-Ray Heating Calculations 11

1.2. COMPONENT DEVELOPMENT AND TESTING 19Fuel Pump Development 19

Development Tests of Salt-Lubricated Bearings 19Development Tests of Conventional Bearings 20Mechanical Seals 21Radiation-Resistant Electric Motors for Use at High Temperatures 22Design Studies of Fuel Pumps 22Frozen-Lead Pump Seal 23

Development of Techniques for Remote Maintenance of the Reactor System 25Mechanical Joint Development 25Evaluation of Expansion Joints for Molten-Salt Reactor Systems 32Remote Maintenance Demonstration Facility 35

Heat Exchanger Development 37Al2Cl6 Thermal-Convection Loop 37Molten-Salt Heat Transfer Coefficient Measurement 38

Design, Construction, and Operation of Materials Testing Loops 39Forced-Circulation Loops 39In-Pile Loops 42

1.3. ENGINEERING RESEARCH 44Physical Property Measurements 44

Enthalpy and Heat Capacity 44Surface Tension 45Apparatus Fabrication and Calibration 46

Molten-Salt Heat-Transfer, Studies 46

1.4. INSTRUMENTATION AND CONTROLS 47Resistance-Type Continuous Fuel Level Indicator 47

1.5. ADVANCED REACTOR DESIGN STUDIES 48Low-Enrichment Graphite-Moderated Molten-Salt Reactors 48A Natural-Convection Molten-Salt Reactor 48



Inconel Thermal-Convection Loop Tests 53INOR-8 Thermal-Convection Loop Tests 53Inconel Forced-Circulation Loop Tests 53Results of Examination of Samples Removed from

INOR-8 Forced-Circulation Loop 9354-1 56Material Inspection 57

General Corrosion Studies 57Carburization of Inconel and INOR-8 by Sodium-Graphite Systems 57Carburization of INOR-8 by Fuel 130-Graphite Systems 59UO2 Precipitation in Fused Fluoride Salts in Contact with Graphite 61Precious-Metal-Base Brazing Alloys in Fuel 130 64

Mechanical Properties of INOR-8 64Influence of Composition on Properties of INOR-8 65High-Temperature Stability of INOR-8 67Welding and Brazing Studies 68

INOR-8 Weldability 68Brazing of Thick Tube Sheets for Heat Exchangers 71Fabrication of Pump Components 73

2.2. RADIATION DAMAGE 76INOR-8 Thermal-Convection Loop for Operation in the LITR 76Graphite Capsules Irradiated in the MTR 76

2.3. CHEMISTRY 78Phase Equilibrium Studies 78

Systems Containing UF4 and/or ThF4 78Solubility of PuF3 in LiF-BeF2 Mixtures 80

Fission-Product Behavior 83Solubility of Noble Gases in Molten Fluoride Mixtures 83Solubility of HF in LiF-BeF2 Mixtures 85Solubilities of Fission-Product Fluorides in Molten Alkali Fluoride-Beryllium Fluoride Solvents 87A Simple Method for the Estimation of Noble Gas Solubilities inMolten Fluoride Mixtures 90Chemical Reactions of Oxides with Fluorides in LiF-BeF2 92

Chemistry of the Corrosion Process 93Activities in Metal Alloys 93Surface Tensions of BeF2 Mixtures 94Disproportionation of Chromous Fluoride 94Effect of Fuel Composition on the Equilibria 3CrF2↔2CrF3 + Cr° and3FeF2↔2FeF3 + Fe° 95Activity Coefficients of CrF2 in NaF-ZrF4 96Equilibrium Amounts of CrF2 in Molten Salts Containing UF4 Which are inContact with Inconel 98Chromium Diffusion in Alloys 99

Corrosion of Metals by Aluminum Chloride 100Corrosion of Inconel by Aluminum Chloride Vapor in a Fused Silica Container 100

Corrosion of Inconel by Aluminum Chloride Vapor in an All-Metal System 100Significance of Experimental Results 101Theoretical Considerations of Aluminum Chloride Vapor Corrosion 101Structural Metal Considerations 102

Gaseous Aluminum Chloride as a Heat Exchange Medium 103Permeability of Graphite by Molten Fluoride Salts 107

Preparation of Purified Materials 107Preparation of Pure Fluoride Compounds 107Production-Scale Operations 108Experimental-Scale Operations 108

2.4. FUEL PROCESSING 110Flowsheet for Fluoride Volatility and HF Dissolution Processing of Molten-Salt Reactor Fluids 110Experimental Studies of Volatility Step 110Solubilities of LiF-BeF2 Salts in Aqueous HF 112

ORNL-2684MOLTEN-SALT REACTOR PROJECT

QUARTERLY PROGRESS REPORTFor Period Ending January 31, 1959

SUMMARY iii


1.1. CONCEPTUAL DESIGN STUDIES AND NUCLEAR CALCULATIONS 3Design of a 30-MWe, One-Region, Experimental Molten-Salt Reactor 3

Reactor System 3Power Plant Arrangement 5Fuel Sampling and Enriching Mechanism 9System Preheating Device 12Off-Gas System Valves 12

Preliminary Design of a 315 MWe Graphite-Moderated Molten-Salt Power-Reactor 18Nuclear Calculations 23

Reactivity Effects in Experimental Molten-Salt Reactor 23Neutron and Gamma Ray Activity in the Secondary Heat Exchanger

of the Interim Design Reactor 24Effect of Ion-Exchange Processing of Rare Earth Fission

Products on Performance of Interim Design Reactor 25Multigroup Oracle Programs for Heterogeneous Reactor Computations 27Oracle Program GHIMSR for Gamma-Heating Calculations 30Initial and Long-Term Nuclear Performance Without Fuel Processing

of Low-Enrichment, One-Region, Graphite-Moderated,Unreflected, Molten-Salt Reactor 30

Initial and Long-Term Nuclear Performance Without Fuel Processing ofOne-Region, Graphite-Moderated, Unreflected, Th232-Conversion,Molten-Salt Reactor 31

Initial Nuclear Performance of One-Region, Graphite-Moderated,Graphite-Reflected, Th232-Conversion, Molten-Salt-Reactor 34

1.2. COMPONENT DEVELOPMENT AND TESTING 38Salt-Lubricated Bearings for Fuel Pumps 38

Hydrodynamic Journal Bearings 38Hydrodynamic Thrust Bearings 39Test Pump Equipped with a Salt-Lubricated Journal Bearing 39Hydrostatic Bearings 41Bearing Mountings 41

Conventional Bearings for Fuel Pumps 41Mechanical Seals for Fuel Pumps 42

Labyrinth and Split-Purge Arrangement 42Bellows-Mounted Seal 42

Pump Endurance Testing 42Frozen-Lead Pump Seal 43Techniques for Remote Maintenance of the Reactor System 47

Mechanical Joint Development 47Remote Maintenance Demonstration Facility 51

Molten-Salt Heat-Transfer-Coefficient Measurement 51Triplex-Tubing Heat Exchanger Development 54

Evaluation of Expansion Joints for Molten-Salt Reactor Systems 54Design, Construction, and Operation of Materials Testing Loops 59



Viscosity 65Enthalpy and Heat Capacity 67

Molten-Salt Heat Transfer Studies 67



Thermal-Convection Loop Tests 75Forced-Circulation Loop Tests 76

General Corrosion Studies 76Carburization of Inconel and INOR-8 in Systems Containing Sodium and Graphite 76Carburization of Inconel and INOR-8 in Systems Containing Fuel 130 and Graphite 78Uranium Precipitation From Fused Fluoride Salts in Contact with Graphite 80Fused Fluoride Salt Penetration Into Graphite 81

Mechanical Properties of INOR-8 82Materials Fabrication Studies 85

Triplex Tubing for Heat Exchangers 85High-Temperature Stability of INOR-8 87Commercial Production of INOR-8 87Evaluations of Composites of INOR-8 and Type 316 Stainless Steel 87

Welding and Brazing Studies 88Heat Exchanger Fabrication 88Welding of INOR-8 90Welding of Dissimilar Metals 95Pump Component Fabrication 96

2.2. CHEMISTRY AND RADIATION DAMAGE 98Phase Equilibrium Studies 98

Systems Containing UF4 and/or ThF4 98The System LiF-PuF3 98The System KF-LiF-BeF2 99Compatibility of Fuel with Chloride Coolants 99

Fission-Product Behavior 100Effect of UF4 on Solubility of CeF3 in LiF-BeF2 Solvents 100Removal of Traces of SmF3 by the Addition of CeF3 to LiF-BeF2-UF4 100Chemical Reactions of Oxides with Fluorides 101

Chemistry of the Corrosion Process 102Activity Coefficients of CrF2 in NaF-ZrF4 102Chromium Diffusion in Alloys 103Sampling of Operating Loops 106Effect of Fuel Composition on Corrosion Equilibria 106

Vapor Pressures of Molten Salts 107BeF2 Mixtures 107UF4 107

Aluminum Chloride Vapor as a Heat Transfer Medium and Turbine Working Fluid 108Estimation of Thermodynamic Properties 108Corrosion of Nickel by AlCl3 109

Permeability of Graphite by Molten Fluoride Mixtures 110Effects of Thermal Cycling on Salt Stability 111Radiation Damage Studies 112

INOR-8 Thermal-Convection Loop for Operation in the LITR 112In-Pile Static Corrosion Test 112

Preparation of Purified Materials 112Fluorides of Chromium 112Synthesis of Simple Fluorides by Reactions with Stannous Fluoride 114Experimental-Scale Purification Operations 114Transfer and Service Operations 114

2.3. FUEL PROCESSING 115Solubility of Neptunium in Aqueous HF Solutions 115Solubility of Corrosion Product Fluorides in HF Solvent 117Solubilities of Uranium and Thorium Tetrafluoride in HF Solvent 118

ORNL-2723MOLTEN-SALT REACTOR PROJECT

QUARTERLY PROGRESS REPORTFor Period Ending April 30, 1959

SUMMARY vi


1.1. NUCLEAR CALCULATIONS AND DESIGN STUDIES 3Nuclear Calculations 3

Effect of Ion-Exchange Processing of Rare-Earth Fission Products on Performance of Interim Design Reactor Fueled with U233 3

Nuclear Performance of a One-Region, Graphite-Moderated,Unreflected, Thorium-Conversion, Molten-Salt-Fueled Reactor 3

Initial Nuclear Performance of One-Region, Graphite-Moderated,Graphite-Reflected, Thorium-Conversion, Molten-Salt-Fueled Reactors 9

Nuclear Performance of Two-Region, Graphite-Moderated,Molten-Salt-Fueled, Breeder Reactor 10

Effects of Fast Neutron Reactions in 9Be on Reactivity of Molten-Salt Reactors 14Oracle Code MSPR-Cornpone 020 20

Design of 30-MWe Experimental Reactor 21Fuel Drain System 22Gamma Heating in the Core Vessel of the 30-MWe Experimental Reactor 22

1.2. COMPONENT DEVELOPMENT AND TESTING 24Salt-Lubricated Bearings for Fuel Pumps 24

Hydrodynamic Journal Bearings 24Hydrodynamic Thrust Bearings 25Test of Pump Equipped with One Salt-Lubricated Journal Bearing 25Bearing Mountings 25

Mechanical Seals for Pumps 27Pump Endurance Testing 27Frozen-Lead Pump Seal 27Techniques for Remote Maintenance of the Reactor System 28Design, Construction, and Operation of Materials Testing Loops 32



Enthalpy and Heat Capacity 37Viscosity 39Surface Tension 39

Heat-Transfer Studies 41Hydrodynamic Studies 44

1.4. INSTRUMENTS AND CONTROLS 47Molten-Salt-Fuel Level Indicators 47INOR-8 High-Temperature Pressure Transmitters 47



INOR-8 Thermal-Convection Loops 52Inconel Thermal-Convection Loops 54

General Corrosion Studies 54Penetration of Graphite by Molten Fluoride Salts 54Uranium Precipitation from Molten Fluoride Salts in Contact with Graphite 58Thermal-Convection-Loop Tests of Brazing Alloys in Fuel 130 60Thermal-Convection-Loop Tests of the Compatibility of INOR-8, Graphite,

and Fuel 130 61Mechanical Properties of INOR-8 63

Creep Tests 63Fatigue Studies 63Shrinkage Characteristics of INOR-8 63

Materials Fabrication Studies 65Effect on INOR-8 of Aging at High Temperatures 65Triplex Heat Exchanger Tubing 67

Welding and Brazing Studies 68Procedures for Welding INOR-8 68Mechanical Properties of INOR-8 Welds 70Fabrication of Apparatus for Testing the Compatibility of Molten Salts and Graphite 73

2.2. CHEMISTRY AND RADIATION DAMAGE 75Phase Equilibrium Studies 75

The System LiF-BeF2-ThF4 75The System NaF-BeF2-ThF4 77The System NaF-ThF4-UF4 78The System SnF2-NH4HF2 78Solubility of PuF3 in Converter Fuels 80Separation of 7LiF from 7LiF-BeF2 80

Fission-Product Behavior 81Precipitation of SmF3 with CeF3 81Chemical Reactions of Oxides with Fluorides in Molten-Fluoride-Salt Solvents 82

Gas Solubilities in Molten Fluoride Salts 85Solubility of Neon in LiF-BeF2 85Solubility of CO2 in NaF-BeF2 85

Chemistry of the Corrosion Process 86Samples from Operating Loops 86Radioactive Tracer Analyses for Iron in Molten Fluoride Salts 87Activities in Metal Alloys 87

Vapor Pressures of Molten Salts 88Permeability of Graphite by Molten Fluoride Salts 88Radiation Damage Studies 91

INOR-8 Thermal Convection Loop for Operation in the LITR 91In-Pile Static Corrosion Tests 91

Preparation of Purified Materials 92Purification, Transfer, and Service Operations 92Fuel Replenishment Tests 92Pure Compounds Prepared with Molten Ammonium Bifluoride 93Reaction of Chromous Fluoride with Stannous Fluoride 94

2.3. FUEL PROCESSING 95


QUARTERLY PROGRESS REPORTFor Period Ending July 31, 1959

SUMMARY iii


1.1. NUCLEAR CALCULATIONS AND DESIGN STUDIES 3Nuclear Performance of a Two-Region, Graphite-Moderated, Molten-Salt Breeder Reactor 3

1.2. COMPONENT DEVELOPMENT AND TESTING 15Molten-Salt-Lubricated Bearings for Fuel Pumps 15

Hydrodynamic Journal Bearings 15Hydrodynamic Thrust Bearings 18Test of Pump Equipped with One Molten-Salt-Lubricated Journal Bearing 18Bearing Mountings 19Self-Welding of INOR-8 19

Mechanical Seals for Pumps 19Pump Endurance Testing 19Remote Maintenance Demonstration Facility 20Frozen-Lead Pump Seal 30Mechanical Joints for the Reactor System 30Design, Construction, and Operation of Materials-Testing Loops 31

Forced-Circulation Corrosion Loops 31In-Pile Loops 31

1.3. ENGINEERING RESEARCH 34Physical-Property Measurements 34

Viscosity 34Enthalpy and Heat Capacity 37Thermal Expansion 39

Heat-Transfer Studies 39

1.4. INSTRUMENTS AND CONTROLS 43Molten-Salt-Fuel Level Indicators 43



INOR-8 Thermal-Convection Loops 47Inconel Thermal-Convection Loops 50INOR-8 Forced-Circulation Loops 55

General Corrosion Studies 59Carburization Tests on Inconel and INOR-8 in Systems

Containing Fuel 130 and Graphite 59Sodium-Graphite Carburization Tests 60Penetration of Graphite by Molten Fluorides 61Removal of Oxide Contaminants from Graphite 62

Mechanical Properties of INOR-8 63

Materials 64Tensile Properties 64Creep Tests 65Relaxation Tests 65Dimensional Instability 65Fatigue Studies 66Carburization 66

Materials Fabrication Studies 67Triplex Heat Exchanger Tubing 67

Welding and Brazing Studies 71Welding of INOR-8 71

2.2. CHEMISTRY AND RADIATION EFFECTS 73Phase Equilibrium Studies 73

The System NaF-ThF4-UF4 73The System NaF-BeF2-ThF4 76The System NaF-PuF3 76Cryoscopy in NaF 78

Gas Solubilities in Molten Fluorides 78Solubility of Xenon in LiF-BeF2 78Solubility of CO2 in NaF-BeF2 79

Fission-Product Behavior 79Solubility of Rare-Earth Fluorides 79Precipitation of Rare-Earth Fluorides by Cooling 80

Reactions of UF4 with Oxides in Molten Fluoride Solvents 81Reaction of UF4 with BeO 81Reaction of UF4 with Strontium Oxide 83Reaction of UF4 with Structural-Metal Oxides 83Reactions of UF4 with Air 83

Chemistry of Corrosion Processes 85Solubility and Thermodynamic Properties of NiF2 in LiF-BeF2 85Activities from Vapor Pressure Measurements 87Tracer Analyses for Determining Efficacy of Reducing Agents 88Analyses of Corrosion-Test Loops 88Stability of Zirconium Monochloride in Air 89

Graphite Compatibility Studies 89Long-Term Loop Tests of Graphite with Circulating Fuel 89Permeability of Graphite by Molten Fluorides 90

Preparation of Purified Materials 93Purification, Transfer, and Service Operations 93Reactions of Stannous Fluoride 94

Radiation Effects 94INOR-8 Thermal-Convection Loop for Operation in the LITR 94In-Pile Static Corrosion Tests 94

2.3. FUEL PROCESSING 96UF6 Solubility in HF-ClF3 96Separation of LiF from CsF 97


QUARTERLY PROGRESS REPORTFor Period Ending October 31, 1959

SUMMARY iii

PART 1. ENGINEERING AND COMPONENT DEVELOPMENT

1.1. COMPONENT DEVELOPMENT AND TESTING 3Molten-Salt-Lubricated Bearings for Fuel Pumps 3

Hydrodynamic Journal Bearings 3Hydrodynamic Thrust Bearings 5Test of Pump Equipped with One Molten-Salt-Lubricated Journal Bearing 5Self-Welding of INOR-8 8Friction Tests on INOR-8 8

Mechanical Seals for Pumps 9MF Performance Loop 9Frozen-Lead Pump Seal 10Remote Maintenance Demonstration Facility 10Design, Construction, and Operation of Materials-Testing Loops 14

Forced-Circulation Corrosion Loops 14Graphite-Metal Seal Tests 16In-Pile Loop 17

1.2. ENGINEERING RESEARCH 19Physical-Property Measurements 19

Viscosity 19Enthalpy and Heat Capacity 20Thermal Expansion 21



2.1. METALLURGY 33Graphite Brazing Studies 33Dynamic-Corrosion Studies 35

Forced-Convection-Loops 35General Corrosion Studies 43

Permeation of Graphite by Molten Salts 43Removal of Oxide Contaminants from Graphite 44Compatibility of INOR-8 and Graphite in Direct Contact 45Brazing-Material Evaluation in Fuel 130 45

2.2. CHEMISTRY AND RADIATION EFFECTS 49Phase Equilibrium Studies 49

The System BeF2-ThF4-UF4 49The System BeF2-ThF4 49The System NaF-BeF2-ThF4 49Molten-Fluoride Solvents 49The Compound NaF-BeF2-3UF4 50

Gas Solubilities in Molten Fluorides 52

Solubility of HF in Fuel Solvents 52Fission-Product Behavior 54

Exchange Reactions in Molten Fluorides 54Chemistry of Corrosion Processes 55

Self-Diffusion Coefficients for Chromium in Nickel Alloys 55Chemical Analyses of Corrosion Test Loops 59Solubility of CrF2 in LiF-BeF2 (62-38 Mole %) 61Equilibrium Measurements on the Reduction of FeF2 by H2 in LiF-BeF2Equilibrium Measurements on the Reduction of CrF2 and FeF2

by H2 in LiF-BeF2 (62-38 Mole %) 62Hygroscopic Behavior and Dehydration of Breeder Fuels 63

Graphite Compatibility Studies 65Penetration of Graphite by Molten Fluorides 65Intercalation of Graphite with Molten Salts 66Diffusion of Rare-Earth Fission Products in Graphite 67

Preparation of Purified Materials 67Technological Operations 67Molten Ammonium Bifluoride as a Reagent 68

Radiation Effects 69Corrosion Tests Under Radiation 69

2.3. FUEL PROCESSING 70Thorium Fluoride Solubility in Aqueous NH4F Solutions 70Fuel-Component Solubility in ClF3-HF 71Fuel-Component Solubility in NO2-HF 71


QUARTERLY PROGRESS REPORTFor Periods Ending January 31 and April 30, 1960

SUMMARY iii

PART 1. ENGINEERING AND COMPONENT DEVELOPMENT

1.1 COMPONENT DEVELOPMENT AND TESTING 3Molten-Salt-Lubricated Bearings for Fuel Pumps 3

Hydrodynamic Journal Bearings 3Test of Pump Equipped with One Molten-Salt-Lubricated Journal Bearing 3Self-Welding of INOR-8 5

Mechanical Seals for Pumps 7Loop for Study of MF-Pump Performance 7Frozen-Lead Pump Seal 8Remote-Maintenance Development Facility 8Design, Construction, and Operation of Materials Testing Loops 12

Forced-Circulation Corrosion Loops 12Mechanical Joints 19Design and Testing of a Frozen-Salt Metal-to-Graphite Joint 19In-Pile Loops 21

1.2 ENGINEERING RESEARCH 23Physical-Property Measurements 23

Enthalpy and Heat Capacity 23Thermal Conductivity 23Surface Tension 26



2.1 METALLURGY 33Dynamic Corrosion Studies 33

Thermal-Convection-Loops 33Inconel Forced-Convection Loops 36INOR-8 Forced-Convection Loops 38

Graphite Brazing Studies 45General Corrosion Studies 53

Permeation of Graphite by Molten Salts 53Removal of Oxygen Contamination from Graphite 59Compatibility of INOR-8 and Graphite 60Corrosion Resistance of Brazing Alloys to Fluoride Fuel 62

2.2 CHEMISTRY AND RADIATION EFFECTS 65Phase Equilibrium Studies 65

The System LiF-BeF2-ZrF4 65The System NaF-ZrF4-ThF4 65The System NaF-ThF4-UF4 66Phase Diagrams for Fluoride Systems 68

Fission-Product Behavior and Reprocessing Chemistry 68

Extraction of Uranium and Protactinium from LiF-BeF2-ThF4 Mixtures 68Chemistry of Corrosion Processes 74

Effect of Oxide on LiF-BeF2-ThF4 and LiF-BeF2-ThF4-UF4 Mixtures 74Radiotracer Studies of the Role of Cr0 Diffusion as a

Controlling Factor in Corrosion by Molten Fluorides 75The Free Energy of Formation of NiF2 79Analysis of Corrosion Test Loops 80Corrosion Equilibria with Unalloyed Cr0 81Melting Points of Chromous Fluoride and Chromic Fluoride 82

Graphite Compatibility 82Intercalation of Graphite 82Permeation of Graphites by Molten Fluoride Fuels 83

Radiation Effects 84Behavior of a Rare-Earth Fission Product in a Graphite-Molten-Salt System 84

Preparation of Purified Materials 86Purification, Handling, and Service Operations 86

2.3 FUEL REPROCESSING 87NO2-HF Solutions 87Aqueous NH4F 87Protactinium Removal 88


QUARTERLY PROGRESS REPORTFor Period Ending July 31, 1960

SUMMARY iii

PART I. MSRE DESIGN, COMPONENT DEVELOPMENT, AND ENGINEERING ANALYSIS

1. MSRE DESIGN 11.1 Introduction 11.2 MSRE Objectives 21.3 Conceptual Designs 21.4 The Reactor Core and Vessel 41.5 The Primary Heat Exchanger 81.6 Radiator 101.7 Drain Tanks 111.8 Equipment Arrangement 121.9 Design of Cover-Gas System 181.10 Design of the Remote-Maintenance System for MSRE 191.11 Modifications to Building 7503 22

2. COMPONENT DEVELOPMENT 242.1 Freeze Flange Development 242.2 Freeze Valves 252.3 Sampler-Enricher Development 252.4 MSRE Core Development 272.5 Remote Maintenance Development Facility 272.6 Forced-Circulation Corrosion Loops 282.7 Pump Development 29

2.7.1 MSRE Primary Pump 292.7.2 MSRE Secondary Pump 302.7.3 Advanced Molten-Salt Pumps 302.7.4 MF-F Pump Performance Loop 312.7.5 Frozen-Lead Pump Seal 312.7.6 MSRE Engineering Test Loop 31

3. REACTOR ENGINEERING ANALYSIS 323.1 Effects of Graphite Shrinkage Under Radiation in the MSRE Core 323.2 Temperature-Rise Effects in MSRE Cores with Round and Flat Fuel Channels 343.3 Temperature of Fuel in a Blocked Passage in the MSRE 393.4 MSRE Reactor Physics 41

3.4.1 Core Calculations 413.4.2 Gamma-Heating Calculations 443.4.3 Drain Tank Criticality 443.4.4 Pump-Bowl Fission-Product Activities 453.4.5 Cell Calculations 45

3.5 Analog Computer Study of MSRE Primary-System Flow Loss 453.5.1 Description of the System Simulated 463.5.2 Analog Computer Program 483.5.3 Simulator Operation 493.5.4 Conditions Used to Obtain Curves 49

PART II. MATERIALS STUDIES

4. METALLURGY 554.1 Dynamic-Corrosion Studies 55

4.1.1 Forced-Convection Loops 554.1.2 Microprobe Analyses of Surface Film 56

4.2 Welding and Brazing Studies 584.2.1 Solidified-Metal-Seal Development 584.2.2 Brazing of Graphite 594.2.3 Heat Exchanger Fabrication 634.2.4 Mechanical Properties of INOR-8 64

4.3 Permeation and Apparent-Density Uniformity in Large Pieces of Graphite 674.3.1 Permeation of AGOT and S-4 Graphites by Molten Salts at Different Pressures 67

4.4 Precipitation from Molten Fluoride Fuel in Contact with Various Volumes of Graphite 694.4.1 Removal of Contamination from Graphite 694.4.2 INOR-8 - Fuel - Graphite Carburization Tests 70

4.5 In-Pile Tests 71

5. CHEMISTRY 725.1 Phase Equilibrium Studies 72

5.1.1 MSRE Fuel and Coolant 725.1.2 Systems Containing ThF4 725.1.3 The System ZrF4-ThF4 74

5.2 Effect of Tetravalent Fluorides on the Freezing Point of Sodium Fluoride 755.2.1 Phase Diagram of Fluoride Systems 775.2.2 The System LiF-YF3 785.2.3 Melting Point of NiF2 79

5.3 Oxide Behavior 795.3.1 Oxide Behavior in Fuels 795.3.2 Zirconium Oxyfluoride and Attempted Preparation of Uranous Oxyfluoride 80

5.4 Graphite Compatibility 805.4.1 Removal of Oxide from Graphite by Treatment with Hydrogen 805.4.2 Behavior of Graphite when Wetted by a Molten Fluoride 81

5.5 Preparation of Purified Materials 81

6. ENGINEERING RESEARCH 836.1 Physical-Property Measurements 83

6.1.1 Surface Tension and Density 836.1.2 Heat Capacity 85

6.2 Heat-Transfer Studies 86

7. FUEL PROCESSING 88


PROGRESS REPORTFor Period From August 1, 1960, to February 28, 1961

SUMMARY iii


1. MSRE DESIGN 11.1 Introduction 11.2 Reactor Core and Vessel 21.3 Fuel Heat Exchanger 41.4 Radiator 51.5 Drain Tanks 91.6 Equipment Arrangement 121.7 Cover-Gas System 151.8 System Heaters 161.9 Design Status of Remote-Maintenance System 201.10 Reactor Control Design 201.11 Design Status of Building and Site 221.12 Reactor Procurement and Installation 23

1.12.1 Division of Work and Schedules 231.12.2 Procurement of Components 24

2. COMPONENT DEVELOPMENT 262.1 Freeze-Flange Development 26

2.1.1 MSRE 6-in. Flanges 262.1.2 Freeze-Flange Thermal-Cycle Tests 27

2.2 Freeze Valves 272.3 Heater Tests 28

2.3.1 Pipe Heaters 282.3.2 Core Heater 31

2.4 Sample-Enricher Development 312.4.1 Sampler-Enricher Concept 312.4.2 Sampler-Enricher Mockup 332.4.3 Solder Freeze Valve 33

2.5 MSRE Core Development 372.6 Helium Purification 402.7 MSRE Maintenance Development 40

2.7.1 Maintenance Philosophy 402.7.2 Remote-Maintenance Development Facility 402.7.3 Semidirect and Remote Tools 422.7.4 MSRE Model 42

2.8 Brazed-Joint Development 422.9 Mechanical-Joint Development 422.10 Forced-Circulation Corrosion Loops 442.11 Graphite-Molybdenum Compatibility Test 442.12 Pump Development 47

2.12.1 MSRE Fuel Pump 472.12.2 MSRE Coolant Pump 532.12.3 Advanced Molten-Salt Pumps 53

2.12.4 Frozen-Lead Pump Seal 532.13 MSRE Engineering Test Loop 532.14 MSRE Instrument Development 59

2.14.1 Thermocouple End Seals 592.14.2 Instrument and Power Disconnects 612.14.3 Pump-Bowl Level Indicator 642.14.4 Single-Point Level Device 67

3. REACTOR ENGINEERING ANALYSIS 703.1 Criticality Calculations 703.2 Reactivity Worth of Control Tubes 723.3 Preliminary Calculations for Core Containing INOR-8 Tubes 733.4 MSRE Biological Shielding and Associated Dose Rates 73



4.1.1 Status of Test Program 774.1.2 Examination of INOR-8 Loops 774.1.3 Examination of Inconel Loops 804.1.4 Molybdenum-Graphite Compatibility Tests 81

4.2 Welding and Brazing Studies 814.2.1 Welding of INOR-8 814.2.2 Solidified-Metal Seal Development 844.2.3 Sump-Type Seal Development 874.2.4 Metal-Fiber Seal Development 87

4.3 INOR-8 Development 894.3.1 Structural Stability of 18% Mo Alloys 89

4.4 Mechanical Properties of INOR-8 894.5 Impregnation of Graphite by Molten Salts 91

4.5.1 Permeation Screening Tests on Large and Small Pipe 934.5.2 Oxidation and Permeation 96

4.6 Precipitation of UO2 from Fluoride Salts 964.7 Precipitation of ZrO2 from MSRE Fuel 964.8 Removal of Oxygen Contamination from Graphite 97

4.8.1 Purging with Molten Fluorides 974.8.2 Purging with Ammonium Bifluoride 984.8.3 Reaction of INOR-8 with the Thermal-Decomposition Products of NH4F-HF 98

5. IN-PILE TESTS 1005.1 Graphite-Fuel Capsule Experiments 1005.2 Examination of Graphite Specimen from Experiment ORNL-47-2 102

6. CHEMISTRY 1096.1 Phase Equilibrium Studies 109

6.1.1 The System LiF-BeF2-ZrF4-ThF4-UF4 1096.1.2 The System LiF-BeF2-ZrF4 1106.1.3 The System LiF-BeF2 1116.1.4 Phase Equilibria in the System NaF-BeF2-ThF4 1116.1.5 The System CsF-ZrF4 1116.1.6 Crystal Structure of LiF-SbF5 1126.1.7 Index to ORNL Work on Fused-Salt Phase Studies 1136.1.8 Solubility of HF in Molten Fluorides 1136.1.9 Solubility of BF3 in MSRE-Type Fuels 1146.1.10 Freezing-Point Depressions in Sodium Fluoride 119

6.2 Oxide Behavior in Fuels 1196.2.1 Identification of Oxides Precipitated from Fuels 1196.2.2 Removal and Precipitation of Oxides from Fuels 120

6.3 Physical Properties 1226.3.1 Density of MSRE Fuel 1226.3.2 Stochastic Correlation of Densities of Molten Fluoride Fuels 1236.3.3 Empirical Equation for Fluidity in LiF-BeF2-UF4 Systems 125

6.4 Graphite Compatibility 1266.4.1 Xenon Diffusion in Graphite:

Effects of Xenon Absorption in Molten-Salt Reactors Containing Graphite 1266.4.2 Wetting of Graphite by MSRE Fused Salt 1296.4.3 Retention of BF3 on Graphite in a Molten-Salt Reactor 130

6.5 Analytical Chemistry 1306.5.1 Proposed Procedures for Analysis of the MSRE Fuel 1306.5.2 Stripping Rate for CO2 from Water in an MSRE Pump-Demonstration System 134

7. ENGINEERING RESEARCH 1387.1 Physical-Property Measurements 138

7.1.1 Enthalpy and Heat Capacity 1387.1.2 Viscosity 139

7.2 Heat-Transfer Studies 140

8. FUEL PROCESSING 1438.1 SbF5-HF Solutions 1438.2 Dissolution Rates for MSRE Fuel Carrier Salt 1448.3 Steady-State Fluorinator 145


PROGRESS REPORTFor Period From March 1 to August 31, 1961

SUMMARY iii


1. MSRE DESIGN 11.1 Introduction 11.2 Reactor Core and Vessel 21.3 Primary Heat Exchanger 41.4 Radiator 41.5 Fuel-Salt Drain Tanks 41.6 Equipment Layout 81.7 Cover-Gas System 111.8 System Heaters 121.9 Design Status of Remote-Maintenance Systems 13

1.9.1 Maintenance-Design Systems 131.9.2 Remote Maintenance by Manipulators 131.9.3 Remote Maintenance by Manual Operations 141.9.4 Assembly Jigs and Fixtures 151.9.5 Graphite-Sample Removal 15

1.10 Reactor-Control Design 161.11 Design Status of Building and Site 191.12 Reactor Procurement and Installation 19

1.12.1 Demolition and Minor Alteration Work to Building 7503 191.12.2 Major Modifications to Building 7503 201.12.3 Procurement of Materials 201.12.4 Procurement of Components 20

1.13 Reactor Instrumentation and Controls Design 211.13.1 Instrument Application Diagram 211.13.2 Electrical Control Circuitry 211.13.3 Layout 211.13.4 Main Control Board 221.13.5 MSRE Data-Handling Study 241.13.6 Single-Point Temperature Alarm System 25


2.1.1 MSRE 5-in. Flanges 282.1.2 Freeze-Flange-Seal Test Facility 28

2.2 Freeze Valves 322.3 Heater Tests 33

2.3.1 Pipe Heaters 332.3.2 Core Heaters 33

2.4 Drain-Tank Coolers 372.5 Sampler-Enricher Development 37

2.5.1 Sampler-Enricher Concept 372.5.2 Solder-Freeze Valve 372.5.3 Sample Capsule 40

2.5.4 Sample-Transport Container and Removal Seal 402.5.5 Sampler-Enricher Design 40

2.6 MSRE Core Development 402.6.1 Heat Transfer Coefficients in the Lower Head of the Reactor Vessel 402.6.2 Fuel-Age Measurements in the Lower Head of the Reactor Vessel 412.6.3 Studies on the Disposition of Fine Particles

in the Lower Head of the Reactor Vessel 422.6.4 Fluid-Dynamic-Induced Power Oscillations 442.6.5 Full-Scale MSRE Core Model 44

2.7 Helium Purification 442.8 Pump Development 46

2.8.1 MSRE Fuel Pump 462.8.2 Water Test of MSRE Coolant Pump 542.8.3 Advanced Molten-Salt Pumps 54

2.9 Graphite-Molybdenum Compatibility Test 542.10 MSRE Engineering-Test Loop 54

2.10.1 Oxide-Flush Run 542.10.2 Freeze-Valve Operation 552.10.3 Level Indicator for Molten Salt (Test Loop) 562.10.4 Graphite-Handling Facility 56

2.11 MSRE Maintenance Development 562.11.1 Maintenance Plan 562.11.2 Remote-Maintenance Mockup 582.11.3 MSRE Model 612.11.4 Portable Maintenance Shield 61

2.12 Brazed-Joint Development 612.13 Mechanical-Joint Development 642.14 Steam Generator 652.15 MSRE Instrument Development 67

2.15.1 Pump Bowl Level Indicator 672.15.2 Single-Point Level Indicator 722.15.3 Temperature Scanner 772.15.4 Thermocouple Attachments and End Seals 78

3. REACTOR ENGINEERING ANALYSIS 833.1 Reactor Physics 83

3.1.1 Analysis of MSRE Temperature Coefficient of Reactivity 833.1.2 Rod Worth, Flux, and Power Density Distributions in MSRE 833.1.3 Gamma-Ray and Fast-Neutron Heating in Thimbles 853.1.4 Reactors with INOR-8 Fuel Tubes 86

3.2 Nitrogen-16 Activity in Fuel Salt 893.3 Residual Activity in Pump Bowl and Heat Exchanger 903.4 Reactor-Cell Shielding 91

3.4.1 Top Shield 913.4.2 Side Shield 92



4.1.1 Examination of INOR-8 Forced-Convection Loops 934.1.2 Molybdenum-Graphite Compatibility Tests 964.1.3 Compatibility of INOR-8 - 2% Nb and Molten Fluorides 994.1.4 Fluoride-Salt Contamination Studies 99

4.2 INOR-8 Development 1004.2.1 Structural Stability of Nickel-Based, 18% Molybdenum Alloys 100

4.2.2 Temperature Range of Melting for INOR-8 1024.2.3 Specific Heat of INOR-8 103

4.3 Total Hemispherical Emittance of INOR-8 1034.4 Welding and Brazing Studies 106

4.4.1 Welding of INOR-8 1064.4.2 Metallographic Examination and Bend Tests on Welds 1064.4.3 Transverse Tensile and Creep Tests 1064.4.4 Welding of INOR-8 to Stainless Steel and Inconel 1084.4.5 Remote Brazing 109

4.5 Mechanical Properties of INOR-8 1124.6 Impregnation of Graphite by Molten Salts 1134.7 Ammonium Bifluoride as an Oxygen-Purging Agent for Graphite 114

4.7.1 Removal of Oxygen from Graphite 1144.7.2 Effects of the Thermal-Decomposition Products

of Ammonium Bifluoride on INOR-8 115

5. IN-PILE TESTS 1175.1 Graphite-Fuel Capsule Experiments 117

6. CHEMISTRY 1196.1 Phase-Equilibrium Studies 119

6.1.1 Systems Involving NaF with ZrF4, ThF4, and UF4 and Other Constituents 1196.1.2 The System NaF-ThF4-UF4 1196.1.3 Stannous Fluoride as a Component of Reactor Fuels 122

6.2 Oxide Behavior in Fuels 1246.2.1 Behavior of MSRE Fuel on Freezing and Effect

of Segregation on Oxide Precipitation 1246.2.2 Oxide Content of Fluoride Melts 125

6.3 Physical and Chemical Properties 1266.3.1 Surface Tension Apparatus for Molten Fluorides 1266.3.2 Volatilization of Iodine from the MSRE Fuel 126

6.4 Graphite Compatibility 1276.4.1 Effect of Cesium Vapor on Graphite 127

6.5 Fuel Production 1286.5.1 Purification Treatments 128

6.6 Analytical Chemistry 1286.6.1 Analyses of MSRE Fuel Mixture 1286.6.2 Analyses of MSRE Cover Gas 129

7. ENGINEERING RESEARCH 1317.1 Physical-Property Measurements 1317.2 Heat-Transfer Studies 133

8. FUEL PROCESSING 1358.1 Preparation and Analysis of Complex Fluorides of SbF5 with KF, AgF, and SrF2 1358.2 Preparation and Analysis of the NaF-MoF6 Complex 1358.3 Preparation and Analysis of Complexes of UF6 with LiF, NaF, and KF 1368.4 Attempt to Separate Rare Earth Fluorides from MSBR Blanket Salt by SbF5 in HF 136


SEMIANNUAL PROGRESS REPORTFor Period Ending February 28, 1962

SUMMARY iii


1. MSRE DESIGN 11.1 Introduction 11.2 Reactor Core and Vessel 21.3 Primary Heat Exchanger 31.4 Radiator 41.5 Fuel-Salt Drain Tanks 41.6 Equipment Layout 41.7 Cover-Gas System 61.8 System Heaters 61.9 Maintenance Design, Assembly Jigs, and Fixtures 71.10 Reactor Procurement and Installation 7

1.10.1 Major Modifications to Building 7503 71.10.2 Construction Outside Building 7503 91.10.3 Planning and Scheduling of the MSRE Installation 91.10.4 Procurement of Materials 91.10.5 Procurement of Components 10

1.11 Reactor Instrumentation and Controls System 101.11.1 Nuclear Control System 101.11.2 Instrument-Application Diagrams 141.11.3 Electrical Control Circuitry 151.11.4 Layout of Instrumentation and Controls System 151.11.5 Control Panels 171.11.6 Data Handling 181.11.7 Process and Personnel Radiation Monitoring 181.11.8 Procurement Status 19


2.1.1 MSRE 5-in. Flanges 212.1.2 Freeze-Flange-Seal Test Facility 21

2.2 Control-Rod Development 242.3 Heater Tests 26

2.3.1 Pipe Heaters 262.3.2 Reactor Vessel Beaters 29

2.4 Drain-Tank Cooler 292.5 Sampler-Enricher System 29

2.5.1 General Concept of Sampler-Enricher 292.5.2 Operational Valve 312.5.3 Removal Seal for Sample Container 312.5.4 Detail Design of Sampler-Enricher 32

2.6 MSRE Core Development 322.6.1 Full-Scale Core Model 322.6.2 Core-Inlet: Flow Distribution 32

2.7 Helium Purification 33

2.8 MSRE Engineering Test Loop (ETL) 342.8.1 Loop Operations 352.8.2 Operation of Freeze Valve 352.8.3 Oxide Removal 372.8.4 HF Treatment 372.8.5 ETL Graphite Facility 37

2.9 MSRE Maintenance Development 412.9.1 Placement and Removal of Freeze-Flange Clamp 412.9.2 Flange Alignment and Pipe-Jacking Tools 412.9.3 Gasket-Replacement Procedures 412.9.4 Miscellaneous Disconnects 432.9.5 Remote Viewing 432.9.6 Component Removal 44

2.10 Brazed-Joint Development 452.10.1 Joint Design 452.10.2 Brazed-Joint Testing 452.10.3 Remote Fabrication of Braze Joint 46

2.11 Mechanical-Joint Development 512.12 Steam Generator 512.13 Pump Development 51

2.13.1 MSRE Fuel Pump 522.13.2 MSRE Coolant Pump 552.13.3 Advanced Molten-Salt Pumps 56

2.14 MSRE Instrument Development 582.14.1 Thermocouple Attachments 582.14.2 Temperature Scanner 582.14.3 Single-Point Temperature-Alarm System 602.14.4 Pump-Bowl Level Indicator 612.14.5 Single-Point Level Indicator 66

3. REACTOR ENGINEERING ANALYSIS 683.1 Reactor Physics 68

3.1.1 Analysis of MSRE Temperature Coefficient 683.1.2 Reactor-Kinetics Studies 693.1.3 Gamma-Heating Survey 70



4.1.1 Fluoride-Salt Contamination Studies 724.1.2 Molybdenum-Graphite Compatibility Tests 744.1.3 Corrosion Effects of Carbon Tetrafluoride 774.1.4 Examination of Corrosion Inserts from INOR-8 Forced-Convection Loops 79

4.2 Welding and Brazing Studies 814.2.1 Heat Exchanger Fabrication 814.2.2 Remote Brazing 844.2.3 Welding of INOR-8 864.2.4 Mechanical Properties of INOR-8-Dissimilar-Metal Welds 88

4.3 Mechanical Properties of INOR-8 894.4 Evaluation of MSRE Type Graphite 89

4.4.1 Comparison of the Permeation of Graphite by Mercury, and Molten Fluorides 924.4.2 Removal of Oxygen Contamination from Graphite

with Thermal Decomposition Products of NH4F-HF 944.4.3 Reaction of ZrO2 with Thermal Decomposition Products of NH4F-HF 94

5. IN-PILE TESTS 975.1 Interaction of Fissioning Fuel with Graphite: Test No. ORNL-MTR-47-3 97

5.1.1 Description of Experiment 975.1.2 Dismantling of In-Pile Assembly 995.1.3 Temperatures 1005.1.4 Gas Analyses 1005.1.5 Test Effects on Graphite 1055.1.6 Analyses of Graphite 1065.1.7 Test Effects on Coupons 1065.1.8 Test Effects on Fuel 1065.1.9 Conclusions 110

5.2 MSRE In-Pile Testing 110

6. CHEMISTRY 1146.1 Phase-Equilibrium Studies 114

6.1.1 The System LiF-BeF2-ZrF4 1146.1.2 The System LiF-BeF2-ZrF4-ThF4-UF4 1166.1.3 Phase Equilibrium Studies in Fluoride Systems 116

6.2 Oxide Behavior in Fuels 1176.2.1 Removal of Oxide from a Flush Salt 1176.2.2 The Behavior of Sulfates in Molten Fluorides 118

6.3 Physical and Chemical Properties of Molten Salts 1216.4 Graphite Compatibility 122

6.4.1 The Behavior of Carbon Tetrafluoride in Molten Fluorides 1226.5 Chemical Aspects of MSRE Safety 124

6.5.1 Physical Effects of Mixing Molten Fuel and Water 1246.5.2 Solubility of Fuel-Salt Components in Water 1276.5.3 Solubility of MSRE Coolant in Water 1296.5.4 Partial Freezing of MSRE Fuel 130

6.6 Fluoride-Salt Production 1306.6.1 Production Rates 130

6.7 Analytical Chemistry 1316.7.1 Oxygen in Nonradioactive MSRE Fuel 1316.7.2 Adaptation of Analytical Methods to Radioactive Fuel 132

7. FUEL PROCESSING 1347.1 MSRE Flowsheet 1327.2 Fluorine Disposal Tests, Using Charcoal 134


SEMIANNUAL PROGRESS REPORTFor Period Ending August 31, 1962

SUMMARY iii

PART 1. MSRE DESIGN, ENGINEERING ANALYSIS, AND COMPONENT DEVELOPMENT

1. MSRE DESIGN 3Design Status 3Reactor Procurement and Installation 4

Major Modifications to Building 7503 4Construction Outside Building 7503 7Procurement of Materials 7Fabrication of Components 8

Reactor Instrumentation and Control Systems 14Layout of Instrumentation and Control System 14Design Status 14Procurement Status 16

2. MSRE REACTOR ANALYSIS 17Nuclear Accident Analyses 17

Calculational Procedures 17Results of Fuel Pump Power Failure Analysis 17Effects of Cold-Slug Accidents 19Results for Filling Accidents 21Effect of Uncontrolled Withdrawal of Rods 21Effect of Graphite Movement 21Results of Concentrated Fuel Addition 22

Reactor Statics Calculations 22Criticality Calculations 24Flux Distributions 24Power Density 24

Steady-State Fuel and Graphite Temperatures 27Temperature Distributions 27Average Temperatures 29

Reactivity Coefficients 33Temperature Coefficients 33Power Coefficient 34

Effective Delayed-Neutron Fractions 35Reactor Kinetics Code Development 37

3. COMPONENT DEVELOPMENT 41Freeze-Flange Development 41

Freeze-Flange-Seal Test 41Thermal-Cycle Test Loop 43Freeze Test in Thermal-Cycle Test Loop 46Test of a Freeze Flange in the Prototype-Fuel-Pump Testing Facility 46

MSRE Control Rod 46Heater Tests 46

Pipe Heaters 46

Activation Analysis of Insulating Materials 47Drain-Tank Coolers 49Sampling and Enriching System 49

Detail Design 49Mockup of Sampling and Enriching System 49

Core Development 49Model Operations 49Velocity Measurements 50Measurement of Heat Transfer Coefficients 51Experiments on the Behavior of Solids 52

MSRE Engineering Test Loop (ETL) 53Frozen-Salt-Sealed Graphite-Container Access Joint 53Salt Composition 54HF Treatment 56Cold-Finger Collections in Cover Gas 56ETL Graphite Treatment 58

MSRE Maintenance 59Placement and Removal of Freeze-Flange Clamps 59Miscellaneous Flange-Servicing Tools 60Remote Viewing 60Portable Maintenance Shield 60

Brazed-Joint Development 61Brazed-Joint Fabrication 61Brazed-Joint Salt Test 62

Mechanical-Joint Development 62Pump Development 62

Fuel Pump Design and Fabrication 62Coolant Pump Design and Fabrication 62Design and Fabrication of Lubrication Stands for Pumps 63Lubrication-Pump Endurance Test 63Drive Motor Design and Fabrication 63Test Pump Fabrication 63Test Facility Construction 63Hydraulic Performance Tests 65PKP Pump Hot Endurance Test 66Test Pump With One Molten-Salt-Lubricated Bearing 66

Instrument Development 66Single-Point Liquid-Level Indicator 66Pump-Bowl Liquid-Level Indication 68Single-Point Temperature Alarm System 68Temperature Scanner 71Thermocouple Development and Testing 74


4. METALLURGY 87Corrosion Effects of CF4 87Welding and Brazing Studios 88

Heat Exchanger Fabrication 88Remote Brazing 92Welding of INOR-8 92

Mechanical Properties of INOR-8 95Properties of Reactor-Quality INOR-8 95Thermal Fatigue of INOR-8 95

Graphite Studies 96Evaluation of Grade TS-281 Graphite 96Effects of Thermal Decomposition Products of NH4F-HF on Graphite-INOR-8 Systems 97

Fabrication of Gd2O3 and Gd2O3-Al2O3 Pellets 98

5. IN-PILE TESTS 100ORNL-MTR-47 Molten-Salt Irradiation Experiments 100

Experiment ORNL-MTR-47-4 100Experiment ORNL-MTR-47-5 102

Post-Irradiation Examination of Experimental Assembly ORNL-MTR-47-3 105Chemical Analyses of Irradiated Fuel for Corrosion Products 105Distribution of Radioactivity and Salt in Irradiated Graphite 106

Post-Irradiation Examination of Experimental Assembly ORNL-MTR-47-4 106Description of Capsule 108Fabrication and Loading of Capsules 108Fuel 109Graphite 109Decay Energy 110Irradiation and Temperature Data 110Production of Xenon and Krypton 110Gas Analyses 112Discussion of Results 115

6. CHEMISTRY 117Phase Equilibrium Studies 117

The System LiF-BeF2-ZrF4 117The System LiF-BeF2-ZrF4-ThF4-UF4 118LiF-UF4 Eutectic as a Concentrated Solution of UF4 for Fuel Makeup 119Fractionation of LiF-BeF2-ZrF4-ThF4-UF4 on Freezing 121Crystal Chemistry 121

Oxide Behavior in Molten Fluorides -Dehydration of LiF 122Physical Properties of Molten Salts 123

Density of LiF-BeF2-ZrF4-UF4 123Estimation of Densities of Molten Fluorides 123

Graphite Compatibility 125Removal of Oxide from Graphite Moderator Elements 125Behavior of CF4 in Molten Fluorides 128

Analytical Chemistry 130Determination of Oxygen in MSRE Fuel Mixtures 130Determination of Oxygen in Graphite 131Homogenization of Radioactive MSRE Fuel Samples 131


8. ENGINEERING RESEARCH ON THERMOPHYSICAL PROPERTIES OF SALT MIXTURES 135Enthalpy 135Viscosity 136


SEMIANNUAL PROGRESS REPORTFor Period Ending January 31, 1963

SUMMARY iii

PART 1. MSRE DESIGN, ENGINEERING ANALYSIS, AND COMPONENT DEVELOPMENT

1. REACTOR ANALYSIS 3Analysis of Filling Accident 3Coolant Salt Activation 4Reactivity Effects of 135Xe 4Reactivity Effects of Changes in Salt and Graphite Densities 6

2. COMPONENT DEVELOPMENTFreeze-Flange Joint Development 10

Thermal-Cycling Test 10Joint Tests in Pump-Testing Facility 10

Tests of Freeze-Valve Control Circuit 12Transfer Valve 12Reactor Drain Valve 14

Reactor Control Rods and Drives 15Control Rod Drive Prototype 15Control Rod 17

Heater Tests 17Pipe Heaters with Reflective Insulation 17

Drain Tank Coolers 23Sampler-Enricher System Mockup 23Flange Disconnects 27Core Development 27

Internal Flow Distribution 27Core Pressure Drop 28

Engineering Test Loop (ETL) 28Results of the Graphite Pretreatment 29Loop Operation 30Operation of the Graphite Container Access Joint 30Graphite Sampling Via Removable Dry Box 32Analysis of Solids Removed from the Graphite Container Access Joint 33Chemical Analysis and HF Treatment of ETL Flush Salt 33ETL Graphite Permeability 35

Xenon Transport in the MSRE 35MSRE Maintenance Development 35Maintenance Study Model 37Pump Development 37

Prototype Pump Operation and Testing 37PKP Fuel Pump High-Temperature Endurance Test 40Lubrication-Pump Endurance Test 40

Instrument Development 40Single-Point Liquid-Level Indicator 40Pump-Bowl Liquid-Level Indicator 41Bubbler-Type Liquid-Level Indicator 43

Temperature Scanner 44High-Temperature NaK-Filled Differential-Pressure Transmitter 45Thermocouple Development and Testing 46

3. MSRE DESIGN 49Design Status 49

Reactor System 49Instrumentation and Controls 49

Procurement and Installation Status 54Subcontract Work at Reactor Site 54Fabrication of Major Reactor Components 54MSRE Cost Estimate Revision 62


4. METALLURGY 65Heat Exchanger Fabrication 65

Sample Tube Bundle 65Tube Joint Inspection 65MSRE Tube Bundle 67

Mechanical Properties of INOR-8 68ASME Boiler and Pressure Vessel Code Allowable Stresses for INOR-8 68Reactor-Quality INOR-8 68

Evaluation of MSRE Graphite 70Salt Permeation of MSRE Graphite 71Thermal Cycling of Salt-Impregnated Graphite 71Tensile Strength of CGB Graphite 74

Development of Gd2O3-Al2O3 Control Rod Elements 76Sample Control Rod Element Testing 76Sintering Characteristics of Gd2O3-Al2O3 Specimens 76

5. RADIATION EFFECTS 80Postirradiation Examination of Experimental Assembly ORNL-MTR-47-3 80Postirradiation Examination of Experimental Assembly ORNL-MTR-47-4 80

Gas Analyses 80Metallographic Evaluation of the Wall of a Capsule

from Experimental Assembly ORNL-MTR-47-4 84Autoradiography of Unopened Capsules 87Bubble Formation in Capsules 88Chemical Analyses of Materials from Experimental Assembly ORNL-MTR-47-4 88Observations of Sectioned Capsules 91Control Experiments on the Fluorination of Graphite 93Conclusions Drawn from the ORNL-MTR-47-4 Experiment 93

Molten-Salt Irradiation Experiment ORNL-MTR-47-5 94Capsule Irradiation and Sampling 94Analyses of Gas Samples Taken During Irradiation 97Pressure Increase During Reactor Shutdown 101Effects of Fissioning in Frozen Fuel 104Pressure Rise Following Termination of Exposure 106Conclusions Drawn from Experiment ORNL-MTR-47-5 106


The System LiF-ZrF4-UF4 108The System UF3-UF4 108

The System LiF-UF3-UF4 109The System LiF-BeF2-UF3 109The System LiF-BeF2-ZrF4-UF3 109Core and Blanket Fluids for Future Reactors 109Crystal Structure of Xenon Fluoride 110

Oxide Behavior in Mixtures of Flush Salt and Fuel Salt 110Physical Properties of Molten Fluorides 116

Vapor Pressures of Fluoride Mixtures 116Densification of LiF Powder 117Density of CrF2 119

Activity Coefficients of ZrF4 in the LiF-ZrF4 System 120Graphite Investigations 122

Evolution of Volatile Impurities from Graphite 122Behavior of Carbon Tetrafluoride in Molten Fluorides 127

Production of Purified Materials 131Pure Uranium Trifluoride 131Preparation of Xenon Tetrafluoride 131Fluorine Gas Manifold 133

Out-of-Pile Irradiation Studies 134Fluorine Evolution from Solid Fluoride Salts Under Irradiation by VanDeGraaf Electrons 134Effect of Beta Radiation on Fused Fluorides 135Gamma Irradiation Experiments with a 10,000-Curie Cobalt-60 Source 135X-ray Irradiation of Inorganic Fluorides 136Reaction of Fluorine with Reduced Fuel 136

Analytical Chemistry 138Methods for the Analysis of Radioactive MSRE Fuel 138Analytical Hot-Cell Mockup for MSRE Fuel Analysis 140



SEMIANNUAL PROGRESS REPORTFor Period Ending July 31, 1963

SUMMARY iii

Part 1. MSRE DESIGN, ENGINEERING ANALYSIS, AND COMPONENT DEVELOPMENT

1. MSRE DESIGN, PROCUREMENT, AND CONSTRUCTION 3Status of Design 3

Mechanical and Process Design 3Instrumentation and Control Design 5

Status of Fabrication of Major Reactor Components 9Reactor Vessel and Control Rod Thimble Assembly 9Heat Exchanger 9Fuel and Coolant Pumps 9Radiator and Radiator Enclosure 9Salt Storage Tanks 9Freeze Flanges 15

Major Procurement 15Moderator Graphite 15Salt Piping and Component Heating Equipment 15Remote Maintenance Equipment 15Reactor Auxiliary Systems 15Instrumentation Fabrication 15Fuel-Salt Sampler and Enricher 16

Status of Construction 16Reactor Cell 16Fuel-Drain-Tank Cell 16Coolant Cell 16CPFF Construction 21

Procurement and Installation of Instrumentation 21

2. COMPONENT DEVELOPMENT 23Drain-Tank Cooler Test 23Heater Tests 23

Drain-Tank Heater 23Pipe Heater with Reflective Insulation 30

Control Rod 30Control Rod Prototype 34

Helium Purification System 34Sampler-Enricher System Mockup 35Flange Disconnects 37Operational and Maintenance Valves 38Design 38Engineering Test Loop 38

Treatment of Flush Salt with HF in ETL Drain Tank Following Oxide Additions 38Treatment of Fuel Salt with HF in ETL Drain Tank 38Loop Operation with Fuel Salt and Graphite 40Operation of the Graphite Container Access Joint 40Analysis for Chromium as an Indication of Corrosion 41

Xenon Transport in MSRE System 44Prototype Pump Testing Facility 44Water Test Pump Loop 44

Maintenance Development 45Pump Development 47

Prototype Pump Operation and Testing 47PKP Fuel Pump High-Temperature Endurance Test 52Test Pump with One Molten-Salt-Lubricated Bearing 54Lubrication-Pump Endurance Test 54Fuel Pump MK-2 54

Instrument Development 54Single-Point Liquid-Level Indicator 54Pump-Bowl Liquid-Level Indicator 55Temperature Scanner 55Thermocouple Development and Testing 56Closed-Circuit Television for Remote Maintenance Viewing 57High-Temperature NaK-Filled Differential Pressure Transmitter 57Bubbler-Type Liquid-Level Indicator 58

3. MSRE REACTOR ANALYSIS 60Nuclear Characteristics of Core 60Control Rod Worth 62

Method of Calculation 62Results 62

Reactivity Shimming 64Inherent Neutron Sources 66Biological Shielding 66

Part 2. MATERIALS STUDIES

4. METALLURGY 71Heat Exchanger Fabrication 71

MSRE Primary Heat Exchanger Brazing 71Ultrasonic Inspection of Tube Joint Brazing 71

Mechanical Properties of INOR-8 73Thermal Fatigue 73Postirradiation Tensile Testing 75

Evaluation of MSRE Graphite 75Chemical Composition and Oxygen Content 75Thermal Cycling of Salt-Impregnated Graphite 76Irradiation Effects on Grade CGB Graphite 76

Removal of Oxygen from Graphite with Molten Salts 77Sintering Characteristics of Gd2O3-Al2O3 78

5. RADIATION EFFECTS 80Postirradiation Examination of Assembly ORNL-MTR-47-4 80

Xenon Recovery from Graphite Cores 80Nonvolatile Constituents in Graphite Cores 81

Effect of Irradiation in Assembly ORNL-MTR-47-5 83Production of CF4 Under Operating Conditions 83

Postirradiation Examination of Assembly ORNL-MTR-47-5 86Fluorine Generation from Decay Energy 86

Out-of-Pile Irradiations of Solid MSRE Salts 94Gamma Irradiations 94X-Ray Irradiations 96

Irradiation with Van de Graaff Electrons 98Irradiation of CF4 103


Phase Behavior in MSRE Fluoride Systems 105Liquid Immiscibility in the System LiF-BeF2-ZrF4 106Petrographic Examination of Irradiated MSRE Salt 108Xenon Fluoride Studies 110Core and Blanket Fluids for Future Reactors 110

Oxygen and Sulfur in Molten Fluorides 111Oxide Behavior in Li2BeF4-ZrF4-UF4 111Removal of Sulfates from Li2BeF4 117

Physical Properties of Molten Fluorides 125Interfacial Behavior of Molten Fluorides with Graphite 125Viscosities of MSRE Fuel and Coolant 129

Oxidation-Reduction Reactions in MSRE Melts 130Chemical Reduction of Dissolved Fluorides of Structural Metals 130Apparent Solubility of UF3 Produced by Reducing Fuel with Excess Zirconium Metal 134

Development and Evaluation of Methods for the Analysis of the Radioactive MSRE Fuel 135Fluoride 136Chromium 136Oxygen 136Nickel 137

Development and Testing of Equipment in the Hot-Cell Mockup 138



SEMIANNUAL PROGRESS REPORTFor Period Ending January 31, 1964

SUMMARY iii

INTRODUCTION 1

Part 1. MSRE DESIGN, ENGINEERING ANALYSIS, AND COMPONENT DEVELOPMENT

1. MSRE DESIGN, PROCUREMENT, AND CONSTRUCTION 5Status of Design 5

Mechanical and Process Design 5Instrumentation and Controls Design 6

Status of Fabrication of Major Reactor Components 9Reactor Vessel and Control Rod Thimble Assembly 9Fuel and Coolant Pumps 9Radiator and Radiator Enclosure 11Salt Storage Tanks 11Freeze Flanges 11

Major Procurement 14Salt Piping and Component Heating Equipment 14Remote Maintenance Equipment 14Reactor Auxiliary Systems 14Neutron Instrument Tube 14Instrumentation 14

Status of Construction 15Reactor Cell 15Fuel Drain Tank Cell 17Coolant Drain Cell 17Radiator Cell and Penthouse 17Auxiliaries 17Leak Testing 17General Instrumentation 19

Cost Plus Fixed Fee Construction 19Mechanical 19Electrical 19

2. COMPONENT DEVELOPMENT 23Primary Heat 23Drain Tank Heater 23Pipe Heaters 24Drain Tank Cooler 24Modified Freeze Valves 27Reactor Drain Valve 27Control Rod Test 29Helium Purification System 31Engineering Test Loop 32Mockup of Sampler-Enricher System 32

Sample Capsule 32

Enriching Capsule 34Sample Transport Container 34Manipulator 34Valves 34Design 34

Maintenance Development 35Television Viewing 35Maintenance Shield 35Long-Handled Tools 35Plans and Procedures 37

Pump Development 37Prototype Pump Operation and Testing 37Rotary Assemblies for the MSRE Fuel- and Coolant-Salt Pumps 40Test Pump with One Molten-Salt-Lubricated Bearing 40PKP Fuel-Pump High-Temperature Endurance Test 40Lubrication-Pump Endurance Test 41MK-2 Fuel Pump 41MSRE Pump Fabrication 41

Instrument Development 41High-Temperature NaK-Filled Differential-Pressure Transmitter 41Thermocouple Development and Testing 42Thermocouple Test Assembly for Temperature Safety Channel 44Temperature Alarm Switches 45Marker Generator for Temperature Scanner 45Bubbler-Type Molten-Salt-Level Indicator 45Float-Type Molten-Salt-Level Transmitter 46Single-Point Level Indicator 46Positive-Position Indicator for MSRE Control Rod 47Pressure-Transmitter Expansion Chamber Assembly 48

3. MSRE REACTOR ANALYSIS 51Nuclear Analysis Report 51Flux Distributions from an External Neutron Source 51Criticality in Drain and Storage Tanks 51Shutdown to Ambient Temperature with Fuel in the Core 53Computational Methods - Revisions in Cross Sections and Group Structure 53Prompt Temperature Coefficient in a Large Molten-Salt Converter Reactor 54


4. METALLURGY 61Mechanical Properties of INOR-8 61

Stress Rupture Strength 61Thermal Fatigue 61

Mechanical Properties of INOR-8 Irradiated at Elevated Temperatures 63Evaluation of MSRE Graphite 67

Structure of Grade CGB Graphite 67Gas Evolution 69Lattice Constants 70Structural Integrity of Retainer Ring and Lattice Bars 70

Thermal Conductivity of Grade CGB Graphite 71Effect of Irradiation on Grade CGB Graphite 72Manufacture of MSRE Control Rod Elements 76

5. RADIATION CHEMISTRY OF THE MSRE SYSTEM 79Experiment ORNL-MTR-47-3:

Examination of INOR-8,Molybdenum, and Pyrolytic-Carbon Specimens 79Postirradiation Examination of Assembly ORNL-MTR-47-4 81

Nonvolatile Constituents in Graphite 82Metallographic Examination of the Graphite 85Implications of Uranium Deposition for the MSRE 85

Postirradiation Examination of Assembly ORNL-MTR-47-5 86Fluorine Evolution from Capsules 3 and 4 During Reactor Shutdowns 86Analysis of Gas from Sealed Capsules 87Visual and Photographic Examination of Capsules 91Preliminary Examination of the Fuel 97Neutron-Flux Determinations 98

Plans for In-Pile Experiment ORNL-MTR-47-6 98Gamma Irradiation of a Simulated MSRE Fuel Salt in the Solid Phase 101

Experimental 101Discussion 104

Fluorine Evolution from Solid Fluoride Salts Under Irradiation by VanDeGraaff Electrons 105Experimental 105Results 106Discussion 108

Effect of Soft X-Rays on Solid Fluorides 110

6. CHEMISTRY 114Phase Equilibrium and Solubility Studies Among Fluorides 114

The System LiF-BeF2-ZrF4 114Crystallization of the MSRE Fuel 117Solubility of Uranium Trifluoride in a Reduced MSRE Fuel-Salt Mixture 117Stability of Uranium Trifluoride in Molten Fluoride Solvents 119Crystal Structure of 6LiF-BeF2-ZrF4 120

Core and Blanket Fluids for Future Reactors 123Chlorides as Fast Reactor Fuels 123Fluoride Salts for Use as Blanket Fluids: The System NaF-KF-ThF4 125Phase Separation of Molten Halides and Lead 126

Removal of Moisture from MSR Graphite 127Interfacial Behavior of Fluorides with Graphite and Metals 132

Graphite 132Metals 135

HF-H2O Equilibria with Molten Fluorides 137Removal of Sulfates from 2LiF-BeF2 141Fluoride Salt Production 146

Production Process 147Raw-Material Procurement 149LiF Densification 149

Development and Evaluation of Methods for the Analysis of the MSRE Fuel 151Electrochemical Analyses 151Oxidation States – Uranium 153Methods Development 154

Mockup of Hot Cell 155



SEMIANNUAL PROGRESS REPORTFor Period Ending July 31, 1964

INTRODUCTION 1

THE PLACE OF MOLTEN-SALT REACTORS IN THE AEC PROGRAME.E. Sinclair 1

MOLTEN-SALT POWER REACTORS AND THE ROLE OF THE MSRE IN THEIR DEVELOPMENTR.B. Briggs 3

MSRE DESIGN AND CONSTRUCTIONW.B. McDonald 22

NUCLEAR CHARACTERISTICS OF THE MSRER.J. Engel 83

INSTRUMENTATION AND CONTROL OF THE MSREJ.R. Tallackson 115

PUMP DEVELOPMENTA.G. Grindell and P.G. Smith 147

COMPONENT DEVELOPMENT IN SUPPORT OF THE MSREDunlap Scott, Jr 167

REMOTE MAINTENANCE OF THE MSRE - Robert Blumberg 190

FUEL PROCESSING FACILITY- R.B. Lindauer 201

PLANS FOR OPERATION OF THE MSRE - P.N. Haubenreich 205

CHEMICAL BASIS FOR MOLTEN-SALT REACTORSW.R. Grimes 214

EFFECTS OF RADIATION ON THE COMPATIBILITY OF MSRE MATERIALSF. F. Blankenship 252

PREPARATION OF MSRE FUEL, COOLANT, AND FLUSH SALTS - J.H. Shaffer 288

FUTURE CHEMICAL DEVELOPMENT - H.F. McDuffie 304

ANALYTICAL CHEMISTRY FOR THE MOLTEN-SALT REACTOR - J.C. White 320

METALLURGICAL DEVELOPMENTS - A. Taboada 330

MSRE GRAPHITE - W.H. Cook 373



SUMMARY iii

INTRODUCTION 1

Part 1. MSRE OPERATIONS AND CONSTRUCTION, ENGINEERINGANALYSIS, AND COMPONENT DEVELOPMENT

1. MSRE OPERATIONS 5Chronological Account 5Component and System Performance 6

Heaters and Insulation 6Freeze Flanges 7Freeze Valves 8Reactor Access Nozzle 9Fuel and Coolant Pumps 9Radiator 10Weighing Systems 10Drain Tank Heat Removal Systems 11Thermal Shield Cooling Water 11Helium and Off-Gas Systems 11

Operations Analysis 12Behavior of Noble Gas in the Fuel System 12Gas in Circulating Loops 14Overflow from Fuel Pump 14Fuel and Coolant Pump Cool-Down Rates 15Drying Out the Salt Systems 15

Instrumentation and Controls Design and Installation 17General 17Reactor Process Instrumentation 17Reactor Nuclear Instrumentation 18Electrical Control Circuits 18Control Panels and Cabinets 19Data System 22Fuel Sampler-Enricher and Chemical Processing System Sampler 22Coolant Salt Sampler 22Personnel and Stack Monitors 23Reliable Instrument Power System 23Remote-Maintenance Closed-Circuit Television 23

MSRE Component Fabrication 24Sampling and Enriching Systems 24Vapor-Condensing System 25

MSRE Construction and Installation 25Pump Installation 25Heat Exchanger Modification and Installation 25Heater and Electrical Installation 26High-Bay Containment 26

Drain Tank System 26Charcoal Beds 26Control Rod Drives 26Sampling and Enriching Systems 26Vapor-Condensing System 26

2. COMPONENT DEVELOPMENT 27Life Tests 27

Pipe Heaters 27Drain Tank Heater 27Drain Tank Cooler 27Freeze Valve 28

Check-Out and Startup of Components 28Freeze Flanges 28Freeze Valves 28Control Rods 29Prototype Control Rod Drive Test 29Control Rod Drive Units 30Diaphragm Leakage 31

Samplers 32Temporary Drain Tank Sampler 32Temporary Fuel System Sampler 32Coolant Salt System Sampler 32

Engineering Test Loop 35Zirconium Oxide Cold Trap 35

Maintenance 36Instrument Development 38

Ultrasonic Single-Point Molten-Salt Level Probe 38Float-Type Molten-Salt Level Transmitters 41Conductivity-Type Single-Point Molten-Salt Level Probe 41MSRE Bubbler-Type Molten-Salt Level Indicator 42Thermocouple Development and Testing 43Temperature Scanner 44Single-Point Temperature Alarm Switches 46High-Temperature Resistance Thermometers 47High-Temperature NaK-Filled Differential Pressure Transmitter 48Helium Control Valve Trim Replacement 48Control Valve Actuator Motion Multiplier 49

Pump Development 50MSRE Pumps 50Other Molten-Salt Pumps 52

3. MSRE REACTOR ANALYSIS 54MSRE Stability Analysis 54

Methods Used 54Results 54

Suppression of Criticality in MSRE Cell in Event of the Maximum Credible Accident 56Effectiveness of a Radial Molten-Salt Blanket on the Breeding Potential

of a One-Fluid Graphite-Moderated Reactor 57Results 57


4. METALLURGY 63Reaction of INOR-8 with Impure Nitrogen 63Alteration of MSRE Heat Exchanger Tube Bundle 64INOR-8 Welding Studies 67

Mechanical Properties of INOR-8 Weld Metal 67INOR-8 Welding Microstructure Study 71

Graphite-to-Metal Joining Development 73Transition Joints 73Brazing Alloy Development 75

Evaluation of MSRE Graphite 76Oxygen Contamination of the MSRE Core Bars and Lattice Bars 76Accessible Voids Content of MSRE Core Graphite 77

Metallographic Examination of Bayonet Tube in Drain Tank Cooler Test 80Mechanical Properties of Irradiated INOR-8 82MSRE Materials Surveillance Testing 83

Control Test for Surveillance Specimen 84

5. RADIATION CHEMISTRY 87Introduction 87Experiment MTR-47-5 87

Graphite 89INOR-8 97Fuel Salt 99

Summary of MTR-47-5 Postirradiation Examinations 102Experiment MTR-47-6 102

Objectives 102Experimental 103Results and Discussion 107

Summary of Experiment MTR-47-6 119

6. CHEMISTRY 121High-Temperature Fluoride Phase Equilibrium Studies 121

Fuel System for the Molten-Salt Reactor Experiment 121Reactions in Molten Salt Systems 129

HF-H2O Equilibrium with Molten Fluorides 129Advantages of On-Stream HF-H2 Sparging of MSR Fuels 136

The Stability of UF3 138Viscosity in the LiF-BeF2 System 144Fuel, Coolant, and Flush Salts for the MSRE 146

The Production Process 147Coolant and Flush Salt Mixtures 147Component Mixtures for the MSRE Fuel 148

Chemistry of Pre-nuclear Use of Fuel and Flushing Salts in the MSRE 150Compositional Analysis of MSRE Salts 150Chemical Analyses of Fuel and Circuit Salts During Pre-nuclear Tests of the MSRE 152

Development and Evaluation of Equipment for Analyzing Radioactive MSRE Fuel Samples 155Sample Preparation 155Sample Analyses 156

Development and Evaluation of Methods for the Analysis of the MSRE Fuel 160Oxide 160Reducing Power 163Electrochemical Analyses 164

7. FUEL PROCESSING 169MSRE Fuel Processing System Status 169Water Monitor 170Chromium Fluoride Trapping 171



SUMMARY vii

INTRODUCTION 1


1. MSRE OPERATIONS 7Chronological Account 7Component and System Performance 10

Control Rods 10Sampler-Enricher 11Freeze Valves 12Freeze Flanges 13Fuel and Coolant System Pressure Control 13Heaters and Insulation 15Reliable Instrument Power System 15Thermal-Shield Cooling Water 16Fuel-Pump Overflow Tank 16

Analysis of Operation 16Basic Nuclear Characteristics 16Dynamic Tests 24Undissolved Gas in Fuel Loop 30Salt Density and Inventory Experience 30External Neutron Source 31

Instrumentation and Controls Design and Installation 32General 32Design, Installation, and Checkout 32Instrumentation and Controls System Performance 40Revisions and Modifications 43Documentation 46

2. COMPONENT DEVELOPMENT 48Life Tests 48

Freeze Valve 48Pipe Heater 48Drain-Tank Heater 48

Checkout and Startup of Components 48Control Rods 48Control Rod Drive Units 49Freeze Valves 51Freeze Valves 204 and 206 51Freeze Valve 103 51Freeze Valves 104, 105, and 106 53Noble-Gas Dynamics 55Sampler-Enricher 56Removal Valve and Seal 56

Manipulator 56Access Port 57Operational Valve 57Sampling Capsule 58Fuel-Processing Sampler 58Off-Gas System 58

Remote Maintenance 60Pump Development 61

MSRE Pumps 61Measurement of the Concentration of Undissolved Helium in Circulating Molten Salt 62Other Molten-Salt Pumps 65

Instrument Development 66Ultrasonic, Single-Point Molten-Salt Level Probe 66High-Temperature NaK-Filled Differential-Pressure Transmitter 70Float-Type Molten-Salt Level Transmitter 71Conductivity-Type, Single-Point Molten-Salt Level Probe 71Single-Point Temperature Alarm Switches 72Helium Control Valve Trim Replacement 72Thermocouple Development and Testing 73

3. MSRE REACTOR ANALYSIS 75Theory of Period Measurements Made with the MSRE During Fuel Circulation 75


4. METALLURGY 81Dynamic Corrosion Studies 81

Corrosion Studies Using Lead as a Coolant 82Revised Thermal Convection Loop Design 85

MSRE Materials Surveillance Testing 87INOR-8 Surveillance Specimens 88Graphite Surveillance Specimens 88Assembly of Surveillance Specimens 90

Evaluation of Radiation-Damage Problems of Graphite for Advanced Molten-Salt Reactors 93Mechanical Properties of Irradiated INOR-8 94

Mechanical Properties of Unirradiated INOR-8 Used in the Reactor Vessel 94Postirradiation Stress-Rupture Properties of INOR-8 102In-Reactor Creep Tests 104

5. RADIATION CHEMISTRY 106Introduction 106Experimental Objectives and Design Considerations 106Experiment Design and Mockup Test Operation 107

6. CHEMISTRY 111Chemistry of the MSRE 111

MSRE Fuel Loading 111MSRE Salt Chemistry During Pre-critical and Zero-Power Experiments 112Examination of Salts After the Zero-Power Experiment 117Density of MSRE Fuel and Coolant Salts 119

Chemistry of LiF-BeF2 Systems 123Solubility of HF and DF in Molten LiF-BeF2 (66-34 Mole%) 123Vapor Pressure 123The Quest for Liquid-Liquid Immiscibility in LiF-BeF2 Melts 126Removal of Iodide from LiF-BeF2 Melts by HF-H2 Sparging 127

Salt Compositions for Use in Advanced Reactor Systems 133Blanket Salt Mixtures for Molten-Salt Breeder Reactors 133Coolants for the Molten-Salt Breeder Reactor 135Viscosity of NaBF4 136

Fuel and Blanket Materials for the Proposed MOSEL Reactor 137Recovery of Protactinium from Fluoride Breeder Blanket Mixtures 137

Introduction 137Facility Description 137Oxide Precipitation of Protactinium 140

Development and Evaluation of Methods for the Analysis of MSRE Fuel 140Determination of Oxide in MSRE Fuel 140Electrochemical Analysis 143Spectrophotometric Studies of Molten-Salt Reactor Fuels 145Analysis of MSRE Blanket Gas 147

Development and Evaluation of Equipment for Analyzing Radioactive MSRE Fuel Samples 148Sample Preparation 148Sample Analyses 148Quality Control Program 148




SUMMARY vii

INTRODUCTION 1


1. MSRE OPERATIONS 7Chronological Account 7Analysis of Experiments 10

Reactivity Balance 10Power Calibration 12Flux Measurements 12

MSRE Dynamic Tests 13Description of Dynamic Tests 13Frequency Response Tests 15Implementation of Pseudorandom Binary Tests 16Analysis Procedures 17Results 18Temperature Response Test 22

Systems Performance 23Off-Gas System 23Salt-Pump Oil Systems 27Treated Cooling-Water System 28Secondary Containment 29Shielding 34

Component Performance 34Radiator 34Other Components 36Inspection of the Fuel Pump 38Heat Treatment of Reactor Vessel 39Stress Analysis of Reactor Piping and Nozzles 40

Instrumentation and Controls 41General 41Safety Instrumentation 41Wide-Range Counting Channels 42Nuclear Instrument Penetration 42BF3 Confidence Instrumentation 44Personnel Monitoring System 45Control Instrumentation 46Operating Experience - Process and Nuclear Instruments 47Data System 49MSRE Training Simulators 50Documentation 51

2. COMPONENT DEVELOPMENT 53Freeze Valves 53Control Rods 53Control Rod Drive Units 54Radiator Doors 54Radiator Heater Electrical Insulation Failure 57Sampler-Enricher 58Coolant Salt Sampler 59Examination of Components from the MSRE Off-Gas System 60

Capillary Flow Restrictor FE 521 60Check Valve CV 533 60Charcoal Bed Inlet Valve HV 621 60Line 522 Pressure Control Valve PCV 522 62Line Filter 522 64Flow Test on the MSRE Filter from Line 522 65

Fuel Processing System Sampler 65Off-Gas Sampler 67Xenon Migration in the MSRE 69Remote Maintenance 70

Practice Before Operation 72Maintenance of Radioactive Systems 72

Pump Development 74MSRE Pumps 74Other Molten-Salt Pumps 75

Instrument Development 77Ultrasonic Single-Point Molten-Salt Level Probe 77High-Temperature NaK-Filled Differential-Pressure Transmitter 77Float-Type Molten-Salt Level Transmitter 78Conductivity-Type Single-Point Molten-Salt Level Probe 78Single-Point Temperature Alarm Switches 78Helium Control Valve Trim Replacement 79Thermocouple Development and Testing 79Temperature Scanner 80

3. MSRE REACTOR ANALYSIS 82Least-Squares Formula for Control Rod Reactivity 82Spatial Distribution of 135Xe Poisoning in MSRE Graphite 87


4. METALLURGY 95Dynamic Corrosion Studies 95MSRE Material Surveillance Tests 96

Reactor Surveillance Specimens 96Surveillance Control Specimens 99

Hot-Cell Metallographic Examination of Hastelloy N from Experiment MTR-47-6for Evidence of Nitriding 100

Postirradiation Metallographic Examination of Capsules 1-4 from Experiment ORNL MTR-47-6 101Development of Graphite-to-Metal Joints 101Tests of Graphite-Molybdenum Brazed Joint for Containing Molten Salts Under Pressure 104New Grades of Graphite 107Evaluation of the Effects of Irradiation on Graphite 108Effects of Irradiation on Hastelloy N 111Weld Studies on Hastelloy N 115

5. CHEMISTRY 122Chemistry of the MSRE 122

Analyses of Flush, Fuel, and Coolant Salts 122Examination of Materials from the MSRE Off-Gas System 124Uranium-Bearing Crystals in Frozen Fuel 128

Physical Chemistry of Fluoride Melts 128Vapor Pressure of Fluoride Melts 128Methods for Predicting Density, Specific Heat,

and Thermal Conductivity in Molten Fluorides 130Oxide Solubilities in MSRE Flush Salt, Fuel Salt, and Their Mixtures 133

Separations in Molten Fluorides 136Evaporative-Distillation Studies on Molten-Salt Fuel Components 136Effective Activity Coefficients by Evaporative Distillation 139Extraction of Rare Earths from Molten Fluorides into Molten Metals 141Removal of Protactinium 145

Radiation Chemistry 152In-Pile Molten-Salt Irradiation Experiment 152

Development and Evaluation of Methods for the Analysis of the MSRE Fuel 154Determination of Oxide in MSRE Fuel 154Voltammetric Determination of Ionic Iron and Nickel in Molten MSRE Fuel 162Development and Evaluation of Equipment and Procedures for

Analyzing Radioactive MSRE Salt Samples 165Sample Analyses 167Quality Control Program 168

6. MOLTEN-SALT BREEDER REACTOR DESIGN STUDIES 172MSBR Plant Design 172

Flowsheet 172Reactor Design 174Fuel Processing 177Heat Exchange and Steam Systems 181

Capital Cost Estimates 182Reactor Power Plant 182Fuel Plant Recycle 182

Nuclear Performance and Fuel Cycle Analyses 186Analysis Procedures 186Basic Assumptions 186Nuclear Design Analysis 189

Power Cost and Fuel Utilization Characteristics 191

7. MOLTEN-SALT REACTOR PROCESSING STUDIES 193Semi-continuous Distillation 194Fuel Reconstitution 199Continuous Fluorination of a Molten Salt 202Chromium Fluoride Trapping 202Design and Evaluation Study 203Description of Fuel Process 204

Description of Fertile Process 208Waste Treatment 208Off-Gas Treatment 209Summary of Capital and Operating Costs 209Processing Cost 210



SUMMARY iii

INTRODUCTION 1

Part 1. MOLTEN-SALT REACTOR EXPERIMENT

1. MSRE OPERATIONS AND ANALYSIS 71.1 Chronological Account of Operations and Maintenance 71.2 Reactivity Balance 10

Reactivity Balances at Power 11Reactivity Balances at Low Power 12

1.3 Xenon Poisoning 13Predicted Steady-State 135Xe Poisoning 14Analysis of Transient 135Xe Poisoning 16

1.4 Circulating Bubbles 221.5 Salt Transport 24

Gradual Transfer to Overflow Tank 24Overfill 24

1.6 Power Measurements 25Heat Balance 25Nuclear Instruments 26Radiator Air Flow 26

1.7 Radiation Heating 27Fuel-Pump Tank 27Reactor Vessel 28Thermal Shield 29

1.8 Reactor Dynamics 291.9 Equipment Performance 35

Heat Transfer 35Main Blowers 39Radiator Enclosure 41Fuel Off-Gas System 43Treated Cooling-Water System 47Component-Cooling System 48Salt-Pump Oil Systems 50Electrical System 51Control Rods and Drives 53Samplers 53Containment 54Shielding and Radiation 56

1.10 Instrumentation and Controls 57Operating Experience --- Process and Nuclear Instruments 58Data System 59Control-System Design 61

2. COMPONENT DEVELOPMENT 652.1 Freeze Valves 65

2.2 Control Rods 652.3 Control-Rod Drive Units 662.4 Radiator Doors 672.5 Sampler-Enricher 70

Replacement of Manipulator Boots 70Replacement of the Capsule Latch 71Repair of an Open Electrical Circuit 71Recovery of a Capsule 72Operational Valve Leakage 72Contamination of Removal Valve Seals 72Miscellaneous Problems 73Changes to the Control Circuit 73

2.6 Coolant Sampler 732.7 Fuel Processing System Sampler 742.8 Off-Gas Filter Assembly 74

Filter Medium 74Heat Dissipation 74Particle Trap 75Charcoal Trap 76

2.9 524 Charcoal Bed 772.10 Remote Maintenance 77

3. PUMP DEVELOPMENT 813.1 MSRE Pumps 81

Molten-Salt Pump Operation in the Prototype Pump Test Facility 81Pump Rotary Element Modification 82Lubrication System 82MK-2 Fuel Pump 82

3.2 Other Molten-Salt Pumps 82PK-P Fuel-Pump High-Temperature Endurance Test 82Pump Containing a Molten-Salt-Lubricated Journal Bearing 82

4. INSTRUMENT DEVELOPMENT 844.1 Temperature Scanner 844.2 High-Temperature, NaK-Filled, Differential-Pressure Transmitter 854.3 Molten-Salt Level Detectors 854.4 Helium Control Valve Trim Replacement 86

5. REACTOR ANALYSIS 885.1 Analysis of Rod Drop Experiments 88

Description of .Experiments 88Analysis Procedures 89Results 91


6. MSRP MATERIALS 976.1 MSR Materials Surveillance Testing 976.2 Evaluation of Possible MSRE Radiator Tubing Contamination with Aluminum 1036.3 Evaluation of Graphite 1026.4 Internal Stress Problem in Graphite Moderator Blocks 1106.5 Brazing of Graphite 1126.6 Corrosion of Graphite-to-Metal Brazed Joints 1156.7 Welding Development of Hastelloy N 117

Effect of Irradiation on the Mechanical Properties of Hastelloy N 117

Characterization of Hastelloy N for Service at 932°C 1256.8 Thermal Convection Loops 130

7. CHEMISTRY 1347.1 Chemistry of the MSRE 134

Behavior of Fuel and Coolant Salt 1347.2 Physical Chemistry of Fluoride Melts 139

Viscosity and Density of Molten Beryllium Fluoride 139Transpiration Studies in Support of the Vacuum Distillation Process 140Estimated Thermophysical Properties of MSBR Coolant Salt 141

7.3 Separation in Molten Fluorides 142Extraction of Rare Earths from Molten Fluorides into Molten Metals 142Removal of Rare Earths from Molten Fluorides by Simultaneous Precipitation with UF3 145Removal of Protactinium from Molten Fluorides by Oxide Precipitation 147Extraction of Protactinium from Molten Fluorides into Molten Metals 148Protactinium Studies in the High-Alpha Molten-Salt Laboratory 156

7.4 Radiation Chemistry 158Xenon Diffusion and Possible Formation of Cesium Carbide in an MSBR 158Fission Product Behavior in the MSRE 165

7.5 Development and Evaluation of Analytical Methods for Molten-Salt Reactors 191Determination of Oxide in Radioactive MSRE Samples 191Spectrophotometric Studies of Molten-Salt Reactor Fuels 193Voltammetric and Chronopotentiometric Studies of Uranium in Molten LiF-BeF2-ZrF4 195In-Line Test Facility 196Analysis of Helium Blanker Gas 196

7.6 Development and Evaluation of Equipment and Proceduresfor Analyzing Radioactive MSEE Salt Samples 199Sample Analyses 200Quality-Control Program 200

Part 3. MOLTEN-SALT BREEDER REACTOR STUDIES

8. MOLTEN-SALT BREEDER REACTOR DESIGN STUDIES 2078.1 Design Changes in MSBR Plant 2078.2 Modular-Type Plant 2128.3 Steam Cycle with Alternative Feedwater Temperature 2178.4 Additional Design Concepts 223

9. MOLTEN-SALT REACTOR PROCESSING STUDIES 2279.1 Semicontinuous Distillation 2289.2 Continuous Fluorination of a Molten Salt 2329.3 Alternative Chemical Processing Methods for an MSBR 233

Reduction Precipitation 235Li-Bi Alloy Extraction 237



SUMMARY 1

INTRODUCTION 9

PART 1. MOLTEN-SALT REACTOR EXPERIMENT

1. MSRE OPERATIONS 111.1 Chronological Account of Operations and Maintenance 111.2 Reactivity Balance 14

Experience 14Circulating Bubbles 17

1.3 Thermal Effects of Operation 18Radiation Heating 18Thermal Cycle History 19

1.4 Reactor Dynamics 201.5 Equipment Performance 21

Heat Transfer 21Main Blowers 25Radiator Enclosure 26Off-Gas Systems 27Cooling-Water Systems 31Component-Cooling System 32Salt-Pump Oil Systems 34Electrical System 34Heaters 35Control Rods and Drives 36Samplers 36Containment 37

2. COMPONENT DEVELOPMENT 392.1 Sampler-Enricher 39

Contamination 39Capsule Support Wire 40Seal Leakage 40Maintenance 40

2.2 Coolant Sampler 412.3 Fuel Processing Sampler 412.4 Off-Gas Sampler 412.5 Off-Gas Filter - Mk II 422.6 Feltmetal Capacity Test 45

Assumptions46

Experimental Procedure 46Results 47

2.7 Examination of the Mk I Off-Gas Filter 47Pressure Drop Tests 48Disassembly 50

Observations 50Analytical Results 55

2.8 Migration of Short-Lived Gaseous Products into the Graphite 562.9 Remote Maintenance 59

Summary of Remote Maintenance Tasks Performed 60Radiation Levels 61Contamination 63Conclusion 63

3. PUMP DEVELOPMENT 643.1 MSRE Pumps 64

Molten-Salt Pump Operation in the Prototype Pump Test Facility 64MK-2 Fuel Pump 64Stress Tests of Pump Tank Discharge-Nozzle Attachment 65Spare Rotary Elements for MSRE Fuel and Coolant Salt Pumps 65Lubrication System 66

3.2 Other Molten-Salt Pumps 66Fuel-Pump High-Temperature Endurance Test Facility 66

4. INSTRUMENT DESIGN AND DEVELOPMENT 674.1 Instrumentation and Controls Design 67

Off-Gas Sampler Design 67Control System Design 68

4.2 MSRE Operating Experience 71Control System Relays 71Temperature Scanner System 71Valves 71Nuclear Instrumentation 71Electronic Switches 72Thermocouples 72Coolant-Pump Radiation Monitor 72Safety System 72

4.3 Data System 734.4 Instrument Development 75

Performance – General 75Temperature Scanner 75High-Temperature NaK-Filled Differential Pressure Transmitter 76Ultrasonic Level Probe 76MSRE Fuel Distillation System Level Probe 76Bell-Float-Type Level Indicator for the Mark II Pump 76

5. MSRE REACTOR ANALYSIS 795.1 Neutron Reaction Rates in the MSRE Spectrum 795.2 Isotopic Changes and Associated Long-Term Reactivity Effects During Reactor Operation 835.3 Analysis of Transient 135Xe Poisoning 86


6. MOLTEN-SALT REACTOR PROGRAM MATERIALS 956.1 MSRE Surveillance Program - Hastelloy N 956.2 Mechanical Properties of Hastelloy N 1036.3 Precursors of MSBR Graphite 1086.4 Graphite Irradiations 1106.5 Brazing of Graphite 111

Large Graphite-to-Hastelloy-N Assemblies 111

6.6 Corrosion Resistance of Graphite-to-Metal Brazed Joints 1116.7 Thermal Convection Loops 1156.8 Evaluation of MSRE Radiator Tubing Contaminated with Aluminum 116

7. CHEMISTRY 1187.1 Chemistry of the MSRE 118

Fuel Salt Composition and Purity 118MSRE Fuel Circuit Corrosion 120Extent of UF4 Reduction During MSRE Fuel Preparation 121Adjustment of the UF3 Concentration in the MSRE Fuel Salt 123

7.2 Fission Product Behavior in the MSRE 124Long-Term Surveillance Specimens 125Uranium Analyses of Graphite Specimens 128Fuel Salt Samples 130Effect of Operating Conditions 131Effect of Beryllium Additions 131Pump Bowl Volatilization and Plating Tests 134Uranium on Pump Bowl Metal Specimens 138Freeze Valve Capsule Experiments 138Special Pump Bowl Tests 141General Discussion of Fission Product Behavior 142

7.3 Physical Chemistry of Fluoride Melts 144The Oxide Chemistry of LiF-BeF2-ZrF4 Mixtures 144Solubilities of SmF3 and NdF3 in Molten LiF-BeF2 (66-34 mole %) 144Possible MSBR Blanket-Salt Mixtures 146

7.4 Separations in Molten Fluorides 149Removal of Rare Earths from Molten Fluorides by Precipitation on Solid UF3 149Extraction of Protactinium from Molten Fluorides into Molten Metals 150Extraction of Rare Earths from Molten Fluorides into Molten Metals 152Protactinium Studies in the High-Alpha Molten-Salt Laboratory 153Preliminary Study of the System LiF-ThF4-PaF4 155

7.5 Development and Evaluation of Analytical Methods for Molten-Salt Reactors 156Determinations of Oxide in MSRE Salts 156Determination of U3/U4 Ratios in Radioactive Fuel by a Hydrogen Reduction Method 158EMF Measurements on the Nickel-Nickel(II) Couple in Molten Fluorides 162Studies of the Anodic Uranium Wave in Molten LiF-BeF-ZrF4 163Spectrophotometric Studies of Molten-Salt Reactor Fuels 163

7.6 Analytical Chemistry Analyses of Radioactive MSRE Fuels 164Sample Analyses 165Quality Control Program 165

8. MOLTEN-SALT CONVECTION LOOPS IN THE ORR 1678.1 Objectives and Description 1678.2 First Loop Experiment 168

In-Pile Irradiation Assembly 168Operations 168Chemical Analysis of Salt 168Corrosion 169Fission Products 169Nuclear Heat and Neutron Flux 169Hot-Cell Examination of Components 169

8.3 Evaluation of System Performance 171Heaters 171Coolers 171Temperature Control 171Sampling and Addition 171

Salt Circulation 1728.4 Second In-Pile Irradiation Assembly 172

Operation 173

PART 3. BREEDER REACTOR DESIGN STUDIES

9. MOLTEN-SALT BREEDER REACTOR DESIGN STUDIES 1749.1 General 1749.2 Flowsheet 1779.3 Reactor Cell Component Arrangement 1799.4 Component Design 182

Reactor Vessel 182Fuel Heat Exchanger 186Blanket Heat Exchanger 190

9.5 Reactor Physics 1939.6 MSBR Gas Handling System 199

Xenon Removal 199Mechanical Design 200Gas Injector System 200Bubble Separator System 202Volume Holdup System 202Noncritical Components 203

10. MOLTEN-SALT REACTOR PROCESSING STUDIES 20410.1 Continuous Fluorination of a Molten Salt 204

Nonprotected System 204Protected System 205

10.2 Molten-Salt Distillation Studies 206Relative Volatility Measurement 206Vaporization Rate Studies 206Buildup of Nonvolatiles at a Vaporizing Surface 208

10.3 Vacuum Distillation Experiment with MSRE Fuel Salt 211



INTRODUCTION 1

SUMMARY 3

PART I. MOLTEN-SALT REACTOR EXPERIMENT

1. MSRE OPERATIONS 131.1 Chronological Account of Operations and Maintenance 131.2 Reactivity Balance 19

Balances at Power 19Balances at Zero Power 21

1.3 Thermal Effects of Operation 22Radiation Heating 22Thermal Cycle History 22Temperature Measurement 22Fuel Salt Afterheat 24

1.4 Equipment Performance 25Heat Transfer 25Main Blowers 26Radiator Enclosure 26Off-Gas Systems 27Cooling Water Systems 29Component Cooling System 29Salt Pump Oil Systems 30Electrical System 31Heaters 31Control Rods and Drives 31Salt Samplers 31Containment 33

2. COMPONENT DEVELOPMENT 362.1 Off-Gas Sampler 362.2 Remote Maintenance 36

Preparations for Shutdown After Run 11 36Evaluation of Remote Maintenance After Run 11 37Repair of Sampler-Enricher and Recovery of Latch 37

2.3 Decontamination Studies 402.4 Development of a Scanning Device for Measuring the Radiation Level of Remote Sources 40

Experiment with a 5-curie 137Cs Gamma Source 41Gamma Scan of the MSRE Heat Exchanger 43Gamma Energy Spectrum Scan of the MSRE Heat Exchanger 43

2.5 Pumps 45Mark-2 Fuel Pump 45Spare Rotary Elements for MSRE Fuel and Coolant Salt Pumps 45Stress Tests of Pump Tank Discharge Nozzle Attachment 46MSRE Oil Pumps 46Oil Pump Endurance Test 46

3. INSTRUMENTS AND CONTROLS 473.1 MSRE Operating Experience 47

Control System Components 47Nuclear Instruments 47Safety System 48

3.2 Control System Design 48

4. MSRE REACTOR ANALYSIS 504.1 Introduction 504.2 Neutron Energy Spectra in MSRE and MSBR 504.3 Other Neutronic Characteristics of MSRE with 233U Fuel 54

Critical Loading, Rod Worth, and Reactivity Coefficients 54Fission Rate and Thermal Flux Spatial Distributions 55Reactor-Average Fluxes and Reaction Cross Sections 55Effect of Circulation on Delayed-Neutron Precursors 58Samarium Poisoning Effects 60

4.4 MSRE Dynamics with 233U Fuel 61

PART 2. MSBR DESIGN AND DEVELOPMENT

5. DESIGN 635.1 General 635.2 Cell Arrangement 655.3 Reactor 715.4 Fuel Heat Exchanger 765.5 Blanket Heat Exchanger 765.6 Fuel Drain Tanks 795.7 Blanket and Coolant Salt Drain Tanks 795.8 Steam Generator-Superheater and Reheater 81

6. REACTOR PHYSICS 826.1 MSBR Physics Analysis 82

Optimization of Reactor Parameters 82Useful Life of Moderator Graphite 84Flux Flattening 87Temperature Coefficients of Reactivity 88

7. SYSTEMS AND COMPONENTS DEVELOPMENT 907.1 Noble-Gas Behavior in the MSBR 907.2 MSBR Fuel Cell Operation with Molten Salt 957.3 Sodium Fluoroborate Circulating Loop Test 957.4 MSBR Pumps 96

Survey of Pump Experience Circulating Liquid Metals and Molten Salts 96Introduction of MSBR Pump Program 96Fuel and Blanket Salt Pumps 97Coolant Salt Pumps 99Water Pump Test Facility 99Molten-Salt Bearing Tests 100Rotor-Dynamics Feasibility Investigation 100Other Molten-Salt Pumps 101

PART 3. CHEMISTRY

8. CHEMISTRY OF THE MSRE 1028.1 MSRE Salt Composition and Purity 102

Fuel Salt 103Coolant Salt 103Flush Salt 103Implications of Current Experience in Future Operations 108

8.2 MSRE Fuel Circuit Corrosion Chemistry 1108.3 Adjustment of the UF3 Concentration of the Fuel Salt 110

9. FISSION PRODUCT BEHAVIOR IN THE MSRE 1169.1 Fission Products in MSRE Cover Gas 1169.2 Fission Products in MSRE Fuel 1199.3 Examination of MSRE Surveillance Specimens After 24,000 MW*hr 121

Examination of Graphite 121Examination of Hastelloy N 124Fission Product Distribution in MSRE 125

9.4 Deposition of Fission Products from MSRE Gas Stream on Metal Specimens 1289.5 Deposition of Fission Products on Graphites in MSRE Pump Bowl 131

10. STUDIES WITH LiF-BeF2 MELTS 13610.1 Oxide Chemistry of ThF4-UF4 Melts 13610.2 Containment of Molten Fluorides in Silica 137

Chemistry 137Spectrophotometric Measurements with Silica Cells 139

10.3 Electrical Conductivity of Molten Fluorides and Fluoroborates 140

11. BEHAVIOR OF MOLYBDENUM FLUORIDES 14211.1 Synthesis of Molybdenum Fluorides 14211.2 Reaction of Molybdenum Fluorides with Molten LiF-BeF2 Mixtures 14311.3 Mass Spectrometry of Molybdenum Fluorides 144

12. SEPARATION OF FISSION PRODUCTS AND OF PROTACTINIUM FROMMOLTEN FLUORIDES 14812.1 Extraction of Protactinium from Molten Fluorides into Molten Metals 14812.2 Stability of Protactinium-Bismuth Solutions Contained in Graphite 14912.3 Attempted Electrolytic Deposition of Protactinium 15112.4 Protactinium Studies in the High-Alpha Molten-Salt Laboratory 153

Reduction of Iron Dissolved in Molten LiF-ThF4 153Thorium Reduction in the Presence of an Iron Surface (Brillo Process) 153Thorium Reduction Followed by Filtration 154Conclusion 154

12.5 MSBR Fuel Reprocessing by Reductive Extraction into Molten Bismuth 15412.6 Reductive Extraction of Cerium from LiF-BeF2 (66-34 Mole %) into Pb-Bi Eutectic Mixture 156

13. BEHAVIOR OF BF3 AND FLUOROBORATE MIXTURES 15813.1 Phase Relations in Fluoroborate Systems 15813.2 Dissociation Vapor Pressures in the NaBF4-NaF System 15913.3 Reactions of Fluoroborates with Chromium and Other Hastelloy N Constituents 161

Apparent Mass Transfer of Nickel 16313.4 Reaction of BF3 with Chromium Metal at 650°C 16313.5 Compatibility of BF3 with Gulfspin-35 Pump Oil at 150°F 164

14. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS FORMOLTEN-SALT REACTORS 166

14.1 Determination of Oxide in MSRE Salts 16714.2 Determination of U3+ in Radioactive Fuel by a Hydrogen Reduction Method 16714.3 In-Line Test Facility 16914.4 Electroreduction of Uranium(IV) in Molten LiF-BeF2-ZrF4 at Fast Scan Rates

and Short Transition Times 16914.5 Spectrophotometric Studies of Molten Fluoride Salts 17114.6 Analysis of Off-Gas from Compatibility Tests of MSRE Pump Oil with BF3 17214.7 Development of a Gas Chromatograph for the MSRE Blanket Gas 172

PART 4. MOLTEN-SALT IRRADIATION EXPERIMENTS

15. MOLTEN-SALT CONVECTION LOOP IN THE ORR 17615.1 Loop Description 17615.2 Operation 17715.3 Operating Temperatures 17915.4 Salt Circulation by Convection 18015.5 Nuclear Heat, Neutron Flux, and Salt Power Density 18015.6 Corrosion 18115.7 Oxygen Analysis 18215.8 Crack in the Core Outlet Pipe 18215.9 Cutup of Loop and Preparation of Samples 18415.10 Metallographic Examination 18515.11 Isotope Activity Calculation from Flux and Inventory History 18715.12 Isotope Activity Balance 19015.13 Uranium-235 Observed in Graphite Samples 19015.14 Penetration of Fission Products into Graphite and Deposition onto Surfaces 19215.15 Gamma Irradiation of Fuel Salt in the Solid Phase 193

PART 5. MATERIALS DEVELOPMENT

16. MSRE SURVEILLANCE PROGRAM 19616.1 General Description of the Surveillance Facility and Observations on Samples Removed 19616.2 Mechanical Properties of the MSRE Hastelloy N Surveillance Specimens 200

17. GRAPHITE STUDIES 20817.1 Materials Procurement and Property Evaluation 20817.2 Graphite Surface Sealing with Metals 21117.3 Gas Impregnation of MSBR Graphites 21217.4 Irradiation of Graphite 215

18. HASTELLOY N STUDIES 21718.1 Improving the Resistance of Hastelloy N to Radiation Damage

by Composition Modifications 21718.2 Aging Studies on Titanium-Modified Hastelloy N 21718.3 Phase Identification Studies in Hastelloy N 21918.4 Hot-Ductility Studies of Zirconium-Bearing Modified Hastelloy N 22118.5 Residual Stress Measurements in Hastelloy N Welds 22318.6 Corrosion Studies 226

Fuel Salts 226Coolant Salts 227Equipment Modifications 230

18.7 Titanium Diffusion in Hastelloy N 23018.8 Hastelloy N-Tellurium Compatibility 233

19. GRAPHITE-TO-METAL JOINING 23619.1 Brazing of Graphite to Hastelloy N 236

Joint Design 236Brazing Development 237

19.2 Compatibility of Graphite-Molybdenum Brazed joints with Molten Fluoride Salts 237

PART 6. MOLTEN-SALT PROCESSING AND PREPARATION

20. VAPOR-LIQUID EQUILIBRIUM DATA IN MOLTEN-SALT MIXTURES 239

21. RELATIVE VOLATILITY MEASUREMENT BY THE TRANSPIRATION METHOD 242

22. DISTILLATION OF MSRE FUEL CARRIER SALT 243

23. STEADY-STATE FISSION PRODUCT CONCENTRATIONS AND HEAT GENERATIONIN AN MSBR AND PROCESSING PLANT 245Heat Generation in a Molten-Salt Still 247

24. REDUCTIVE EXTRACTION OF RARE EARTHS FROM FUEL. SALT 248

25. MODIFICATIONS TO MSRE FUEL PROCESSING FACILITY FOR SHORT DECAY CYCLE 251

26. PREPARATION OF 233UF4-7LiF FUEL CONCENTRATE FOR THE MSRE 252Process 252Equipment and Operations 252Status 253



INTRODUCTION ix

SUMMARY xi


1. MSRE OPERATIONS 11.1 Chronological Account of Operations and Maintenance 11.2 Operations Analysis 3

1.2.1 Reactivity Balance 31.2.2 Variations in Reactor Access Nozzle Temperatures 71.2.3 Radiation Heating 91.2.4 Thermal Cycle History 91.2.5 236U Indication of Integrated Power 10

1.3 Equipment Performance 111.3.1 Salt Pumps 111.3.2 Heat Transfer 111.3.3 Salt Samplers 121.3.4 Control Rods and Drives 131.3.5 Radiator Enclosure 131.3.6 Off-Gas Systems 131.3.7 Main Blowers 141.3.8 Heaters 151.3.9 Electrical System 151.3.10 Salt Pump Oil Systems 161.3.11 Cooling Water System 161.3.12 Component Cooling Systems 171.3.13 Containment and Ventilation 17

2. COMPONENT DEVELOPMENT 192.1 Off-Gas Sampler 192.2 Fuel Sampler-Enricher 202.3 Decontamination Studies 202.4 Study of Pin-Hole Camera for Gamma Source Mapping 222.5 Freeze-Flange Thermal Cycle Tests 232.6 Pumps 29

2.6.1 Mark 2 Fuel Pump 292.6.2 MSRE Oil Pumps 292.6.3 Oil Pump Endurance Test 29

3. INSTRUMENTS AND CONTROLS 303.1 MSRE Operating Experience 30

3.1.1 Safety System Components 303.1.2 Thermocouples 303.1.3 Other Instruments and Controls 31

3.2 Control System Design 313.3 MSRE Neutron Noise Analysis 32

3.4 Test of MSRE Rod Control System Under Simulated 233U Loading Conditions 323.5 Analog Computer Studies of the MSRE System with 233U Fuel Loading 35

4. MSRE REACTOR ANALYSIS 364.1 Introduction 364.2 Simulation of Nuclear Excursion Incidents 37

4.2.1 Uncontrolled Rod Withdrawal 374.2.2 Return of Separated Uranium to the Core 40

4.3 Detection of Anomalous Reactivity Effects 47


5. DESIGN 515.1 General 515.2 Flow Diagram 515.3 Plant Layout 535.4 Reactor Vessel and Core 555.5 Primary Heat Exchanger 615.6 Fuel Drain Tank 61

6. REACTOR PHYSICS 666.1 MSBR Physics Analysis 66

6.1.1 Reference Reactor 666.1.2 Fuel-Cycle Costs 706.1.3 Cell Calculations 706.1.4 Reactivity Coefficients 716.1.5 Measurements of Eta for 233U and 235U in the MSRE 72

7. SYSTEMS AND COMPONENTS DEVELOPMENT 747.1 Noble Gas Behavior in an MSBR 747.2 Sodium Fluoroborate Circulating Loop Test 757.3 MSBR Pumps 75

7.3.1 Pump Program 757.3.2 Fuel Salt Pump 767.3.3 Coolant Salt Pump 787.3.4 Molten-Salt Pump Test Facility 787.3.5 Molten-Salt Bearing Program 797.3.6 Rotor-Dynamics Feasibility Investigation 82

7.4 Remote Maintenance 82

8. MSBR INSTRUMENTATION AND CONTROLS 858.1 Analog Computer Studies 85

PART 3. CHEMISTRY

9. CHEMISTRY OF THE MSRE 889.1 Fuel Salt Composition and Purity 899.2 MSRE Fuel Circuit Corrosion Chemistry 909.3 Isotopic Composition of Uranium in MSRE Fuel Salt 93

10. FISSION PRODUCT BEHAVIOR 9410.1 Fission Product Behavior in the MSRE 94

10.1.1 Fission Products in the MSRE Fuel 9410.1.2 Fission Products in the MSRE Cover Gas 96

10.1.3 Deposition of Fission Products from MSRE Cover Gas on Metal Specimens 9610.1.4 Examination of MSRE Surveillance Specimens After 24,000 MW*hr 9910.1.5 Hot-Cell Tests on Fission Product Volatilization from Molten MSRE Fuel 10010.1.6 Miscellaneous Tests 108

10.2 Fission Product Distribution in an MSRE Graphite Surveillance Specimen 11510.3 Proton Reaction Analysis for Lithium and Fluorine in MSR Graphite 11910.4 Surface Phenomena in Molten Salts 125

11. CHEMISTRY OF FISSION PRODUCT FLUORIDES 12911.1 Properties of Molybdenum Fluorides 129

11.1.1 Synthesis of MoF3 and MoF5 12911.1.2 Lithium Fluoromolybdates(III) 13011.1.3 Kinetics of MoF3 Behavior in 2LiF-BeF2 131

11.2 Mass Spectrometry of the Molybdenum Fluorides 13411.3 Spectroscopic Studies of Fission Product Fluorides 13611.4 Preparation of Niobium Pentafluoride 137

12. PHYSICAL CHEMISTRY OF MOLTEN SALTS 13812.1 Thermodynamics of LiF-BeF2 Melts by EMF Measurements 13812.2 Electrolysis of LiF-BeF2 Mixtures with a Bismuth Cathode 14012.3 A Review of Electrical Conductivities in Molten Fluoride Systems 14112.4 Measurement of Specific Conductance in LiF-BeF2 (66-34 mole %) 14412.5 A Stirred Reaction Vessel for Molten Fluorides 14612.6 The Chemistry of Silica in Molten LiF-BeF2 14612.7 A Silica Cell and Furnace for Electrochemical Measurements with Fused Fluorides 14912.8 Status of the Molten-Salt Chemistry Information Center 149

13. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL REPROCESSING TECHNOLOGY 15213.1 MSBR Fuel Reprocessing by Reductive Extraction into Molten Bismuth 15213.2 Removal of Structural Metal Fluorides from a Simulated MSRE Fuel Solvent 155

13.2.1 Reduction of Structural Metal Fluorides 15513.2.2 Salt Filtration Studies 157

13.3 Protactinium Studies in the High-Alpha Molten-Salt Laboratory 15913.3.1 Protactinium Reduction by Solid Thorium in the Near Absence of Iron 15913.3.2 Reduction of Protactinium by Bismuth-Uranium Alloy 15913.3.3 Reduction of Protactinium by Bismuth-Thorium Alloys 16013.3.4 Two-Region Breeder Blanket Composition 16013.3.5 Single-Region Fuel Composition 161

14. BEHAVIOR OF BF3 AND FLUOROBORATE MIXTURES 16614.1 Phase Relations in Fluoroborate Systems 166

14.1.1 The System NaF-NaBF4-KBF4-KF 16614.2 Nonideality of Mixing in Potassium Fluoroborate-Sodium (or Potassium) Fluoride Systems 16714.3 Heat Content of NaBF4-NaF (92.5-7.5 mole %) 16814.4 The Solubility of Thorium Metal in Lithium Fluoride-Thorium Tetrafluoride Mixtures 16814.5 Dissociation Pressure of BF3 for the MSRE Substitute Coolant 16914.6 Chemical Thermodynamics of the System NaBF4NaF 17014.7 Corrosion of Hastelloy N and Its Constituents in Fluoroborate Melts 17114.8 Compatibility and Immiscibility of Molten Fluorides 171


15. MOLTEN-SALT CONVECTION LOOP IN THE ORR 17415.1 Isotope Activity Balance (Loop 2) 17515.2 Penetration of Fission Products into Graphite and Deposition onto Surfaces 175

15.3 Studies of Surface Wetting of Graphite by Molten Salt 17815.4 Design of a Third In-Pile Molten-Salt Loop 178

16. GAMMA IRRADIATION OF FLUOROBORATE 180


17. MSRE SURVEILLANCE PROGRAM 18317.1 General Comments 18317.2 Examination of Hastelloy N Specimens from MSRE Surveillance Facility 184

18. GRAPHITE STUDIES 18818.1 Procurement of Special Grades of Graphite 18818.2 Porosity Created in Grade AXF Graphite by Oxidation Pretreatment 18918.3 X-Ray Studies on Graphite 19018.4 Gas Impregnation of Graphite with Carbon 19118.5 Graphite Surface Sealing with Metals 19218.6 Graphite Irradiation Program 19518.7 Nondestructive Testing Studies 196

18.7.1 Graphite Ultrasonic Velocity Measurements 19618.7.2 Low-Voltage Radiography 197

19. HASTELLOY N 19819.1 Influence of Strain Rate on the Fracture Strain of Hastelloy N 19819.2 Status of Development of the Modified Alloy 20119.3 Effect of Carbon and Titanium on the Unirradiated

Creep-Rupture Properties of Ni-Mo-Cr Alloys 20419.4 Electrical Resistivity of Titanium-Modified Hastelloy N 20519.5 Electron Microscope Studies of Hastelloy N 206

19.5.1 Phase Identification Studies in Hastelloy N 20619.5.2 Effect of Silicon on Precipitation in Hastelloy N 20919.5.3 Titanium-Modified Hastelloy N 21219.5.4 Summary 213

19.6 Diffusion of Titanium in Modified Hastelloy N 21319.7 Measurement of Residual Stresses in Hastelloy N Welds 215

19.7.1 Experimental Results 21619.8 Application of the Narrow-Gap Welding Process to the joining of Hastelloy N 21719.9 Natural Circulation Loops and Test Capsules 218

19.9.1 Fuel Salts 21819.9.2 Blanket Salts 22119.9.3 Coolant Salts 221

19.10 Forced Circulation Loop 22619.11 Oxidation of Hastelloy N 228

20. GRAPHITE-TO-METAL JOINING 23120.1 Graphite Brazing Development 23120.2 Radiation Stability of Brazing Alloys of Interest for Brazing Graphite 23420.3 Graphite-to Hastelloy N Transition joint 235

20.3.1 Conceptual Design 23520.3.2 Heavy-Metal Alloy Development 236

20.4 Nondestructive Testing Evaluation of Graphite-to-Metal joints 238

21. SUPPORT FOR COMPONENTS DEVELOPMENT PROGRAM 24021.1 Remote Welding 240


22. MEASUREMENT OF DISTRIBUTION COEFFICIENTS IN MOLTEN-SALT-METAL SYSTEMS 24122.1 Extraction of Uranium and Rare Earths from Fuel Salt of Two-Fluid MSBR's 24222.2 Extraction of Uranium from Single-Fluid MSBR Fuel 24322.3 Experimental Procedure and Lithium "Loss" 247

23. PROTACTINIUM REMOVAL FROM A SINGLE-FLUID MSBR 248

24. CONTINUOUS FLUORINATION OF MOLTEN SALT 252

25. RELATIVE VOLATILITY MEASUREMENTS BY THE TRANSPIRATION METHOD 255


27. PROTACTINIUM REMOVAL FROM A TWO-FLUID MSBR 260

28. RECOVERY OF URANIUM FROM MSRE FUEL SALT BY FLUORINATION 26428.1 Fluorination-Corrosion Study 26428.2 Fission Product Behavior - Analytical Assistance Program 266

29. MSRE FUEL SALT PROCESSING 269

30. PREPARATION OF 7LiF-233UF4 FUEL CONCENTRATE FOR THE MSRE 27030.1 Equipment Changes 27030.2 Equipment and Process Status 271

31. DECAY HEAT GENERATION RATE IN A SINGLE-REGION MOLTEN-SALT REACTOR 275



INTRODUCTION xi

SUMMARY xiii


1. MSRE OPERATIONS 11.1 Chronological Account of Operations and Maintenance 11.2 Chemical Processing 4

1.2.1 Operating Summary 41.2.2 Data Analysis 61.2.3 Equipment Performance 10

1.3 Reactor Operations Analysis 121.3.1 Long-Term Variations in Reactivity 121.3.2 Reactivity Effects of Radiation Damage to Graphite 141.3.3 Dynamics Tests at the End of 235U Operation 141.3.4 Correlation of Circulating Void Fraction and Neutron Noise 181.3.5 Determination of Circulating Void Fraction 191.3.6 Neutron Flux near Reactor Vessel 191.3.7 Observation of Fission Products After Shutdown 221.3.8 Unscheduled Scrams During 235U Operation 241.3.9 Thermal Cycle History 24

1.4 Equipment 241.4.1 Heat Transfer 241.4.2 Salt Samplers 261.4.3 Control Rods and Drives 291.4.4 Radiator Enclosure 291.4.5 Off-Gas System 301.4.6 Main Blowers 301.4.7 Heaters 311.4.8 Oil Systems for Salt Pumps 311.4.9 Component Cooling System 311.4.10 Containment and Ventilation 32

2. COMPONENT DEVELOPMENT 332.1 Freeze-Flange Thermal-Cycle Tests 33

2.1.1 Facility Operation Problems 332.1.2 Inspection of the Flanges 33

2.2 Gamma Spectrometric Measurements of Fission Product Deposition 362.3 Gamma Source Mapping with Pinhole Camera Photography 402.4 Pumps 40

2.4.1 Mark 2 Fuel Pump 402.4.2 Oil Pump Endurance 40

3. INSTRUMENTS AND CONTROLS 433.1 MSRE Operating Experience 433.2 Control System Design 43

3.3 Analog Investigation of Control with 233U Fuel 44

4. MSRE REACTOR ANALYSIS 454.1 Delayed Neutron Effectiveness 454.2 Theoretical Dynamic Analysis for 233U Fuel 46

4.2.1 Time Response 464.2.2 Frequency-Response Calculations 484.2.3 Stability Analysis 48


5. DESIGN 535.1 General 535.2 Plant Layout 535.3 Flowsheet 565.4 Reactor Vessel and Core 585.6 Primary Heat Exchangers 645.6 Primary Drain System 666.7 Maintenance Procedures and Equipment 66

6. REACTOR PHYSICS 686.1 Physics Analysis of MSBR 686.2 Physics Analysis of MSBE 70

7. SYSTEMS AND COMPONENTS DEVELOPMENT 727.1 Noble-Gas Migration in the MSBR Reference Design 727.2 Bubble Generator 747.3 Bubble Separator 747.4 Sodium Fluoroborate Circulating Test Loop 75

7.4.1 Pumping Characteristics of Sodium Fluoroborate Salt 767.4.2 Restrictions in the Gas System 777.4.3 Salt Compatibility 787.4.4 NaBF4 Freeze Valve 78

7.5 MSBR Pumps 787.5.1 Pump Program 787.5.2 Fuel-Salt Pump 807.5.3 Coolant-Salt Pump 817.5.4 Molten-Salt Pump Test Facility 817.5.5 Rotor-Dynamics Feasibility Study 837.5.6 Molten-Salt Bearing Program 84

7.6 Molten-Salt Steam Generator 847.7 Remote Welding 85

8. MSBR INSTRUMENTATION AND CONTROLS 888.1 Control System Analyses 88

8.1.1 System Control Analysis 888.1.2 Dynamic Analysis of MSBR Steam Generator 91

8.2 Calculations of Neutron Decay After Shutdown 938.3 High-Temperature Resistance Thermometer Evaluation 94

9. HEAT TRANSFER AND THERMOPHYSICAL PROPERTIES 969.1 Introduction 969.2 Heat Transfer 969.3 Thermophysical Properties 100

9.3.1 Thermal Conductivity 100

9.3.2 Heat Capacity 1039.3.3 Property Prediction 104

9.4 Mass Transfer to Circulating Bubbles 106

PART 3. CHEMISTRY

10. CHEMISTRY OF THE MSRE 10910.1 Chemical Feasibility of Fueling Molten-Salt Reactors with Plutonium Trifluoride 11010.2 Chemical Determination of Burnup in 235U Operations 11010.3 High-Temperature Fuel Salt-Graphite Compatibility Experiment 11210.4 Examination of a Corroded Cap from a Sample Capsule 113


11.1.1 Examination of MSRE Surveillance Specimens After 64,000 MW*hr 11511.2 Fission Product Profiles in Three MSRE Graphite Surveillance Specimens 141

11.2.1 Pyrolytic Graphite 14111.2.2 Unimpregnated CGB (Specimen P-55) 14211.2.3 Impregnated CGB (Specimen V-28) 14211.2.4 Overall Results 146

11.3 Analysis of MSRE Graphite Sample X-13 for Fluorine and Lithium 14611.4 Surface Phenomena in Molten Salts 150

12. PHYSICAL CHEMISTRY OF MOLTEN SALTS 15312.1 Molybdenum Fluoride Chemistry 153

12.1.1 Synthesis of MoF3, MoF4, MoF5, and RuF3 15312.1.2 Kinetic Behavior of MoF3 in Molten 2LiF-BeF2 154

12.2 Properties of the Alkali Fluoroborates 15512.2.1 Phase Relations in Fluoroborate Systems 15512.2.2 Crystal Structure of Sodium Tetrafluoroborate 15612.2.3 Heat Content of NaBF4 and KBF4 15712.2.4 Dissociation Pressure and Chemical Thermodynamics of the System KBF4-KF 15812.2.5 Density and Viscosity of Sodium Fluoroborate Melts 15912.2.6 Corrosion of Chromium by Molten Fluoroborates 160

12.3 Physical Properties of LiF-ThF4 and LiF-BeF2-ThF4 Mixtures 16112.3.1 CeF3 Solubility in Molten Mixtures of LiF, BeF2, and ThF4 16112.3.2 Solubility of Thorium Metal in Molten

Lithium Fluoride-Thorium Fluoride Mixtures 16212.3.3 Heat Content of LiF-BeF2-ThF4 (72-16-12 mole %) 16312.3.4 Technical Memorandum on Physical Properties of Molten Salts 163

12.4 Electrochemical Studies 16312.4.1 Electrical Conductivity of Molten LiF-BeF2 Mixtures 16312.4.2 Estimated Electrical Conductivities of MSBR-Related Salts 16612.4.3 Reference Electrodes for Molten Fluorides 167

12.5 Spectroscopy of Fluoride Media 16812.5.1 The Diamond-Windowed Cell 16812.5.2 Molybdenum(III) Fluoride Solution Spectra 17012.5.3 K3MoF6 Synthesis and Spectrum 17012.5.4 Studies of the Vapor Phase over MoF3 Solutions 170

12.6 Oxide Chemistry of Fluoride Melts Containing ThF4 and UF4 17112.7 Chemistry of Silica in Molten LiF-BeF2 172

13. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL REPROCESSING TECHNOLOGY 17413.1 Reductive Extraction of 233Pa and Uranium from

Molten LiF-BeF2-ThF4 Mixtures into Bismuth 174

13.2 Reductive Extraction of Rare Earths from Molten Mixtures of LiF, BeF2, and ThF4 into Bismuth and Bismuth Alloy Mixtures 17613.2.1 Effect of Salt Composition 17613.2.2 Effect of Metal-Phase Composition 178

13.3 Protactinium Studies in the High-Alpha Molten-Salt Laboratory 18013.3.1 Tests Dealing with the Possibility of Thorium Carbide Formation 18113.3.2 Tests Dealing with the Possibility of Oxide Contamination 18113.3.3 Experiment with Molybdenum Container 18413.3.4 Conclusions 185

14. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS FORMOLTEN-SALT REACTORS 18614.1 Determination of Oxide in MSRE Salts 18614.2 Determination of Uranium (III) in Radioactive MSRE Fuel by a

Hydrogen-Reduction Method 18814.3 Determination of Total Reducing Power of Radioactive MSRE Salts 18914.4 Disproportionation of Electrochemically Generated U(V)

in LiF-BeF2 ZrF4 at 500°C 19014.5 Exchange Current Measurements on the Nickel-Nickel(II) Couple in Molten Fluorides 19114.6 Voltammetric Studies of Chromium(II) in Molten LiF-BeF2-ZrF4 at 500°C 19214.7 Development of a Molten-Salt Spectrophotometric Facility for Hot-Cell Use 19214.8 Spectra of U(V) and U(VI) Species in Molten Fluoride Salts 19314.9 Absorption Spectra of Several 3d Transition Metal Ions in Molten Fluoride Solution 19414.10 Simultaneous Electrochemical and Spectrophotometric Study

of Solutes in Molten Fluoride Salts 19514.11 Development of a Gas Chromatograph for Analysis of the MSRE Blanket Gas 19514.12 Analysis of MSRE Helium for Hydrocarbons 19614.13 Measurement by Ge(Li) Gamma Spectroscopy of Fission Products Deposited in

Components of the MSRE 19614.14 In-Pile Fission-Product Penetration in MSRE and Pyrolytic Graphite 19714.15 Precision Analysis of 235U by Delayed-Neutron Counting 19814.16 High-Precision Polarographic Determination of Uranium 19814.17 A Precise Determination of Uranium in MSRE Fuel 198


15. MOLTEN-SALT CONVECTION LOOP IN THE ORR 20015.1 Studies of Surface Wetting of Graphite by Molten Salt 200

16. GAMMA IRRADIATION OF FLUOROBORATE 20316.1 Gamma Dose Rates and Decay of Spent Fuel Elements 20316.2 Second Fluoroborate Irradiation Experiment 20316.3 Estimated Neutron Effects 205

17. EXAMINATION OF MSRE OFF-GAS JUMPER LINE 20617.1 Chemical Analysis 20717.2 Radiochemical Analysis 20717.3 Discussion 208


18. MSRE SURVEILLANCE PROGRAM 21118.1 MSRE Surveillance Specimens 211

18.1.1 Examinations of Specimens Removed 213

18.1.2 New Specimens in the Surveillance Assembly 21418.2 Mechanical Properties of MSRE Surveillance Specimens 216

19. GRAPHITE STUDIES 22419.1 Procurement of Graphite 22419.2 Physical Property Measurements 22619.3 Bend Testing of Graphite 22719.4 X-Ray 8tudies 22819.5 Gas Impregnation of Graphite with Carbon 23019.6 Graphite Surface Sealing with Metals 23119.7 Graphite Irradiation Experiments 23319.8 Small-Angle X-Ray Scattering Measurements in Graphite 235

20. HASTELLOY N 23720.1 Development of Titanium-Modified Hastelloy N 237

20.1.1 Commercial Melts 23720.1.2 Laboratory Melts 238

20.2 Aging of Modified Hastelloy N 23920.3 Influence of Irradiation Temperatures on the Post-irradiation Mechanical

Properties of Titanium-Modified Hastelloy N 24420.4 Electron Microscope Studies 247

20.4.1 Precipitation in Standard Hastelloy N 24720.4.2 Titanium-Modified Hastelloy N 247

20.5 Weldability of Titanium-Modified Hastelloy N 25020.6 Measurement of Residual Stresses in Hastelloy N Welds 25620.7 Corrosion Studies 257

20.7.1 Fuel Salts 25720.7.2 Blanket Salts 26220.7.3 Coolant Salts 26420.7.4 Haynes Alloy No. 25 Corrosion 26520.7.5 Flow Velocity in Natural Circulation Loops 266

20.8 Forced Convection Loop 26620.9 Oxidation of Ni-Mo-Cr-Fe Alloys 269

21. GRAPHITE-TO-METAL JOINING 27121.1 Introduction 27121.2 Graphite Brazing 27121.3 Graphite-Hastelloy N Transition Joint Development 272

2l.3.1 Heavy-Metal Alloy Development 27321.3.2 Fabrication and Testing of Joints 273

21.4 Nondestructive Testing of Graphite-to-Metal Joints 276

22. SUPPORT FOR COMPONENTS DEVELOPMENT PROGRAM 27822.1 Welding Irradiated Materials 278

22.1.1 Development of Apparatus and Procedures for Welding Irradiated Samples 27822.1.2 Mechanical Properties of Hastelloy N Welded After Irradiation 278

22.2 Molten-Salt Distillation Experiment 28222.2.1 Examination of Specimens from the Distillation Experiment 28222.2.2 Examination of Plug from Distillation Vessel 285

22.3 X-Ray Examination of Bearing Coatings 28522.4 Liquid-Level Probe Analysis 28522.5 Fabrication of Fluted Tubing for Enhanced Heat Transfer 289


INTRODUCTION 291

23. MEASUREMENT OF DISTRIBUTION COEFFICIENTS IN MOLTEN-SALT-METAL SYSTEMS 29223.1 Extraction of Protactinium from Single-Fluid MSBR Fuels 29223.2 Extraction of Thorium and Rare Earths from Single-Fluid MSBR Fuels 29523.3 Solubility of Thorium in Bismuth 297

24. SIMULATED MOLTEN-SALT-LIQUID-BISMUTH CONTACTOR STUDIES 298

25. REDUCTIVE EXTRACTION ENGINEERING STUDIES 301

26. CONTINUOUS FLUORINATION OF MOLTEN SALT 302


28. RELATIVE VOLATILITY MEASUREMENTS BY THE TRANSPIRATION METHOD 309

29. PREPARATION OF 7LiF-233UF4 CONCENTRATE FOR THE MSRE 31129.1 Cold Shakedown Run 31129.2 Production of the 7LiF-233UF4 Concentrate 31129.3 Packaging of the Concentrate 313

30. DEVELOPMENT OF THE TWO-STEP PROCESS FOR PREPARATION OF7LiF-233UF4 FUEL CONCENTRATE FOR THE MSRE 31830.1 Laboratory Test of Low-Temperature Process 31830.2 Physical Behavior of Powder Beds 32030.3 Oxide Impurity Level in a Product 32030.4 Feasibility of Use of the Two-Step Process 320

31. PROCESS DEVELOPMENT ON THE RECOVERY OF URANIUM FROM MSRE 32131.1 Fluorination-Valence State Study 32131.2 Equilibrium of UF6 with NaF at 400°C; Retention of Uranium 32331.3 Effect of Temperature on Sorption of UF6 by NaF:

Comparison of High- and Low-Surface-Area Material 32431.4 Linear Velocity in Sorption Process 32531.5 Disposal of Gaseous F2 in KOH-KI-K2B4O7 Solution 32531.6 Corrosion 32531.7 Helium Dilution of Fluorine 32631.8 Formation of KIO3 Precipitate 32631.9 Neutron Poisoning with K2B4O7 32631.10 Handling of Mist and Smoke from Scrub Solution 326

ORGANIZATION CHART 327



INTRODUCTION xi

SUMMARY xiii


1. MSRE OPERATIONS 11.1 Chronological Account of Operations and Maintenance 11.2 233U Zero-Power Tests 5

1.2.1 Critical Experiment 51.2.2 Control Rod Calibration 71.2.3 Temperature Coefficient of Reactivity 81.2.4 Concentration Coefficient of Reactivity 9

1.3 Operations Analysis 91.3.1 System Dynamics 91.3.2 Gas in the Fuel Salt 111.3.3 Neutron and Pressure Noise Measurements 161.3.4 Perturbations in Nuclear Power 161.3.5 Salt Transfer to Overflow Tank 211.3.6 Thermal-Convection Heat-Removal Test 221.3.7 Radiation Heating 231.3.8 Thermal Cycle History 23

1.4 Equipment 241.4.1 233U Loading Equipment 241.4.2 Salt Samplers 251.4.3 Control Rods and Drives 261.4.4 Off-Gas System 271.4.5 Component Cooling System 281.4.6 Containment and Ventilation 281.4.7 Electrical System 281.4.8 Heaters 291.4.9 Other 29

2. COMPONENT DEVELOPMENT 302.1 Freeze-Flange Thermal-Cycle Test 302.2 Pumps 31

2.2.1 Mark 2 Fuel Pump 312.2.2 Oil Pump Endurance Test 32

3. INSTRUMENTATION AND CONTROLS 333.1 MSRE Operating Experience 333.2 Controls System Design 333.3 MSRE Computer System 33

4. MSRE REACTOR ANALYSIS 354.1 Long-Term Isotopic Changes and Reactivity Effects During Operation with 233U 354.2 Analysis of Zero Power Rod-Calibration Experiments 37

4.2.1 Rod-Drop Experiments 384.2.2 Reactivity Effect of Excess Uranium 404.2.3 Summary of Rod-Calibration Information 41

4.3 Calculations of Reactivity Variations from Power-Time Records 434.4 Theoretical Analysis of Dynamics with 233U Fuel 45


5. DESIGN 495.1 General 495.2 Plant Layout 495.3 Reactor 525.4 Primary Heat Exchangers 575.5 Steam Generator and Superheater 575.6 Steam Reheater 595.7 Removal of Reactor Afterheat 59

5.7.1 Introduction 595.7.2 Sources of Afterheat 595.7.3 Heat-Removal Systems 60

5.8 Distribution of Noble-Metal Fission Products and Their Decay Heat 625.9 Reactor Temperatures, Flows, and Heat Transfer 64

5.9.1 Reactor Core 645.9.2 Flow and Temperature in Radial Reflector 675.9.3 Flow and Temperature in Axial Reflectors 695.9.4 Vessel Temperatures 70

5.10 Estimated Costs of 1000 MWe MSBR Power Station 705.11 MSBE Design 71

5.11.1 Introduction 715.11.2 Description of Reactor Plant 74

6. REACTOR PHYSICS 766.1 Physics Analysis of MSBR 76

6.1.1 Optimization of the MSBR 766.1.2 The One-Fluid MSBR Reference Design 776.1.3 Nuclear Design Studies 776.1.4 Optimum Thorium Concentration in MSBR 806.1.5 Improvements in Computational Tools 826.1.6 Gamma and Neutron Heating in MSBR 83

6.2 Physics Analysis of MSBE 846.2.1 MSBE Design Studies 84

6.3 MSBR Experimental Physics 876.3.1 Initial Results of the Experiment to Measure alpha(235U) in the MSRE 87

7. SYSTEMS AND COMPONENTS DEVELOPMENT 907.1 Off-Gas System 90

7.1.1 Volume Holdup Tank 907.2 Noble-Gas Migration in the MSBR 92

7.2.1 Contribution of the Noble Gases to Afterheat in the Graphite 927.2.2 Distribution of Decay Heat in the MSBR Off-Gas System 94

7.3 Bubble Generator 957.4 Bubble Separator 967.5 Molten-Salt Steam Generator Test Stand 987.6 Sodium Fluoroborate Circulating Test Loop 98

7.6.1 Pumping Characteristics of Sodium Fluoroborate Salt 1007.6.2 Control of Salt Composition 100

7.6.3 Corrosion Product Deposition 1027.6.4 Gas System Studies 102

7.7 MSBR Pumps 1067.7.1 MSBR Primary-Salt Pump 1067.7.2 Pump Program for the Molten-Salt Breeder Experiment 1087.7.3 MSBE Salt Pump Test Stand 1097.7.4 ALPHA Pump 109

7.8 Remote Welding 109

8. MSBR INSTRUMENTATION AND CONTROLS 1138.1 Control System Analysis 1138.2 Calculations of Neutron Decay After Shutdown 115

8.2.1 Calculation of the Effect of the Beryllium PhotoneutronReaction on Neutron Density After Shutdown 115

8.2.2 Calculation of Neutron Density Following Loss of Primary Flow 1158.3 Dynamic Analysis of MSBR Steam Generator 1168.4 High-Temperature Resistance Thermometer Evaluation 116

9. HEAT TRANSFER AND THERMOPHYSICAL PROPERTIES 1199.1 Heat Transfer 1199.2 Thermophysical Properties 122

9.2.1 Thermal Conductivity 1229.3 Mass Transfer to Circulating Bubbles 124

PART 3. CHEMISTRY

10. CHEMISTRY OF THE MSRE 12910.1 A Material Balance for the MSRE Fuel Salt 12910.2 MSRE Fuel Circuit Corrosion Chemistry 13010.3 Adjustment of U3+/ΣU Concentration of the MSRE Fuel Salt 13310.4 Examination of Simulated MSRE Fuel Mixture for Foam-Producing Properties 13510.5 Foaming Behavior in Molten Salts 137


11.1.1 Examination of Graphite Surveillance Specimens 13811.1.2 Distribution of Fission Products in the MSRE 13811.1.3 Fission Product Inventory During 233U Operation 13811.1.4 Response of 95Nb Activity to Fuel Redox Chemistry 13911.1.5 MSRE Off-Gas Analyzer-Sampler 14011.1.6 Examination of Material Recovered from MSRE Off-Gas Line 143

11.2 Fission Product Volatilization Tests 14511.2.1 Chemical Probe Tests 14511.2.2 Electric Charge of the Radioactive Aerosols 14811.2.3 Electron Microscope Tests 14811.2.4 Aerosol Deposition from a Helium Stream 14811.2.5 Closed Tube Diffusion Tests 15011.2.6 Volatilization of MSRE Salt in the Absence of Radioactivity 15011.2.7 Summary and Interpretation of Hot-Cell Test Results 15111.2.8 Attempt to Sample Foam in Pump Bowl 151

11.3 Laboratory Tests on Aerosol Formation Over Molten Salts and Transfer ofNiobium from Salt to Bismuth 153

11.4 The Chemistry of the Noble Fission Product Fluorides 15711.4.1 Molybdenum Fluoride Synthesis, Characterization, and Stability 15711.4.2 Mass Spectrometric Studies of Fluorides 159

12. PHYSICAL CHEMISTRY OF MOLTEN SALTS 16312.1 CeF3 Solubility in Molten Mixtures of LiF, BeF2, and ThF4 16312.2 Correlation of CeF3 Solubility with Solvent Composition 16412.3 Zone Melting of Fluoride Salts 166

12.3.1 Phase Behavior 16712.3.2 Zone Melting 16812.3.3 Cyclic Slow Cooling 16812.3.4 Cerium 168

12.4 Behavior of CeF3 in the Fractional Crystallization of ThF4 from LiF-BeF2 -ThF4 Melts 16812.5 Properties of the Alkali Fluoroborates 169

12.5.1 Phase Relations in Fluoroborate Systems 16912.5.2 The System Na-KF-BF3 17012.5.3 The System KF-KBF4 17012.5.4 The System NaBF4-KBF4 17112.5.5 The System NaF-NaBF4 171

12.6 Limits of Miscibility in Molten Salt Systems: KBF4-LiF, Li2BeF4-KI, and Li2BeF4-KBF4 17112.6.1 The System KBF4-LiF 17112.6.2 The System Li2BeF4-KI 17212.6.3 The System Li2BeF4- KBF4 172

12.7 Solubility of Thorium Metal in Molten Lithium Fluoride-Thorium Fluoride Mixtures 17212.8 The Crystal Structure of KBF4 17312.9 Densities of Molten Salts 17412.10 Spectroscopy of Fluoride Media 175

12.10.1 The Diamond-Windowed Cell 17512.10.2 Salt Purification for Fluoride Spectroscopy 175

12.11 The Distribution of U4+ Between Molten LiF-BeF2 ThF4-UF4and a (U-Th)O2 Solid Solution 176

12.12 An Ni-NiO-BeO Electrode as a Reference Electrode in Molten Fluorides 17812.13 Emf Measurements with Concentration Cells with Transference in Molten

Mixtures of LiF and BeF2 18012.14 Electrical Conductance of Molten KNO3 18212.15 Electrical Conductance of Molten Beryllium Fluoride 184

13. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL REPROCESSING TECHNOLOGY 18713.1 Simultaneous Extraction of Zirconium and Uranium and of Zirconium and Protactinium 18713.2 Protactinium Studies in the High Alpha Molten-Salt Laboratory 18813.3 Further Studies of the Reductive Extraction of Protactinium from Single-Fluid

MSBR Fuel Salt by Thorium in Molten Bismuth 18913.4 Reductive Extraction of Rare Earths from Molten Mixtures of LiF, BeF2, and

ThF4 into Bismuth 19113.5 Metal Phases Other than Bismuth for Rare-Earth Extraction 19213.6 Separation of Cerium from Thorium in Bismuth by Cold Zone Deposition of

Thorium Bismuthide 19313.7 Extraction of Thorium by Electrolytic Reduction into Flowing Liquid Lead from

Molten Mixtures of LiF, BeF2, ThF4, and Rare-Earth Fluorides 195

14. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODSFOR MOLTEN-SALT REACTORS 197

14.1 Determination of Oxide in MSRE Fuel 19714.2 Determination of the Oxidation State of Constituents of MSRE Fuel 197

14.2.1 Determination of Total Reducing Power of MSR Salts 19714.2.2 Determination of U(III) in Radioactive MSRE Fuel by a Hydrogen

Reduction Method 19914.2.3 Voltammetric Determination of U(IV)/U(III) Ratios in MSRE Fuel 200

14.3 Emf, Voltammetric, and Spectrophotometric Measurements on the

U(IV)/U(III) Couple in Molten LiF-BeF2 -ZrF4 20114.4 Emf Measurements in Molten Fluorides20214.5 Development of a Molten-Salt Spectrophotometric Facility for Hot-Cell Use 20214.6 Absorption Spectra of 3d Transition-Metal Ions in Molten LiF-BeF2 20414.7 Effect of Reductants on Metal-Fluoride-Salt Wetting Behavior 20514.8 Determination of Contaminants in the Blanket Gas of NaBF4 Tests 20514.9 Determination of Bismuth in MSRP Salts 208

14.9.1 Polarography 20814.9.2 Spectrophotometry 20814.9.3 Emission Spectrography 20814.9.4 Polarographic Shipping 20814.9.5 Isotopic Exchange 208


15. MOLTEN-SALT CONVECTION LOOP IN ORR 21015.1 Studies of Surface Wetting of Graphite by Molten Salt 210


16. MSRE SURVEILLANCE PROGRAM 21116.1 Examination of Particles Removed from Pump Bowl with Magnets 211

16.1.1 Observations on Particles from Magnet FP-15-53 21216.1.2 Observations on Particles from Magnet FP-16-2 213

17. GRAPHITE STUDIES 21417.1 Fundamental Studies of Radiation Damage Mechanisms in Graphite 21417.2 Graphitization Chemistry and Binder System Development 21517.3 Hot Pressing of Graphite Pellets Using Various Binders 21617.4 Procurement and Physical Property Measurements on New Grades of Graphite 21717.5 Physical Properties of Graphites 21917.6 X-Ray Studies 21917.7 Electron Microscopy of Graphite 22117.8 Gas Impregnation of Graphite with Carbon 22117.9 Graphite Irradiation in HFIR 22417.10 Calculation of Lifetime and Induced Stresses in MSBR Cores 229

18. HASTELLOY N 23218.1 Influence of Titanium and Carbon on the Mechanical Properties of Nickel-Base Alloys 23218.2 Aging of Modified Hastelloy N 23318.3 Influence of Irradiation Temperature on the Creep-Rupture Properties of Hastelloy N 23518.4 Electron Microscopy Studies 24018.5 Measurement of Residual Stresses in Hastelloy N Welds 24218.6 Corrosion Studies 243

18.6.1 Fuel Salts 24318.6.2 Fertile-Fissile Salts 24318.6.3 Blanket Salts 24518.6.4 Coolant Salts 24618.6.5 Comparison of the Kinetic Behavior of Nickel- and Iron-Based

Alloys in Molten Fluoride Salts 24818.7 Forced Convection Loop 25318.8 Oxidation of Hastelloy N 254

19. SUPPORT FOR CHEMICAL PROCESSING 26119.1 Graphite-Hastelloy N Transition Joint Development 26119.2 Development of Corrosion-Resistant Brazing Alloys for Molybdenum 26119.3 Examination of Mo-TZM Capsule 26219.4 Bismuth Corrosion Studies 264

20. SUPPORT FOR COMPONENTS DEVELOPMENT PROGRAM 26720.1 Remote Welding Development 26720.2 Thermal Cycling Tests on Coated Bearing Specimens 267


21. FLOWSHEET ANALYSIS 27021.1 Proposed Reductive Extraction Processing Flowsheet for a Single-Fluid MSBR 27021.2 Protactinium Removal from a Single-Fluid MSBR 27221.3 Removal of Rare Earths from a Single-Fluid MSBR 27321.4 Material Balance Calculations 275

21.4.1 MSBR Nuclear Data Compilation 27521.4.2 MSBR Material Balance Calculations 27521.4.3 MSBR Processing Plant Design Calculations 277

22. MEASUREMENT OF DISTRIBUTION COEFFICIENTS IN MOLTEN-SALT-METAL SYSTEMS 27922.1 Extraction of Uranium, Zirconium, Protactinium, and Plutonium from

Single-Fluid MSBR Fuels 27922.2 Solubility of Protactinium in Bismuth 28222.3 Extraction of Thorium and Rare Earths from Single-Fluid MSBR Fuels 28422.4 Metal Transfer Process Studies 28522.5 Effect of Other Components on the Solubility of Thorium in Bismuth 287

23. ENGINEERING DEVELOPMENT OF PROCESS OPERATIONS 28823.1 Electrolytic Cell Development 288

23.1.1 Quartz Static Cell Experiments 28823.1.2 All-Metal Static Cell Experiment 291

23.2 Reductive Extraction Engineering Studies 29123.3 Simulated Molten-Salt-Liquid-Bismuth Contactor Studies 29323.4 Design of a Continuous Electrolytic Cell Testing System 29623.5 Experimental Facilities for Reductive Extraction Development Work 297





INTRODUCTION ix

SUMMARY xi



1.2.1 Reactivity Balance 41.2.2 Reactivity Effects of Graphite Distortion 51.2.3 Gas in the Fuel System 61.2.4 Diagnosis by Noise Analysis 101.2.5 Fission Product Distributions in Fuel System 111.2.6 Salt Transfer to Overflow Tank 121.2.7 Coolant Salt Flow Rate 121.2.8 Radiation Heating 131.2.9 Service Life 131.2.10 Heat Transfer 14

1.3 Equipment 141.3.1 New Irradiation-Specimen Array for Core 141.3.2 Salt Samplers 151.3.3 Control Rods and Drives 161.3.4 Off-Gas System 171.3.5 Component Cooling System 191.3.6 Containment and Ventilation 191.3.7 Heaters and Electrical System 191.3.8 Oil Systems for Salt Pumps 201.3.9 Radiator and Main Blowers 20

1.4 Remote Maintenance 20

2. MSRE REACTOR ANALYSIS 222.1 Introduction 222.2 Definition of Average Reaction Cross Sections 222.3 Results of Revised Cross-Section Calculations 232.4 Effects on Other MSRE Neutronic Characteristics 25

3. COMPONENT DEVELOPMENT 273.1 Freeze-Flange Thermal-Cycle Test 27


3.2 Pumps 293.2.1 Mark 2 Fuel Pump 293.2.2 Oil Pump Endurance Test 31

3.3 MSRE Remote Gamma Spectrometer 313.3.1 Description of the Equipment 313.3.2 Test Program 33

3.4 Noble-Metal Migration in the MSRE 33

4. INSTRUMENTS AND CONTROLS 364.1 Development of Reactor Diagnosis Using Noise Analysis 364.2 MSRE Operating Experience 374.3 Control System Design 37


5. DESIGN 395.1 General 395.2 Plant Layout 435.3 Seismic Review of MSBR Plant Conceptual Design 495.4 Cooling Requirements for Waste Storage Pit 515.5 Primary Salt Drain Tank 525.6 Primary-Salt-Drain-Tank Operation and Afterheat Removal System 555.7 Gamma Heating in MSBR Heat Exchangers 56


6.1.1 One-Fluid MSBR Reference Design: Two-Dimensional Calculation 596.1.2 MSBR Nuclear Design Studies 606.1.3 Alternate MSBR Design Studies 616.1.4 Gamma and Neutron Heating in MSBR 636.1.5 MSBR Dynamics and Control 66

6.2 Physics Analysis of MSBE 696.2.1 MSBE Design Studies 69

6.3 MSR Experimental Physics 706.3.1 235U Capture-to-Absorption Ratio in the Fuel of the MSRE 706.3.2 233U Capture-to-Absorption Ratio in the Fuel of the MSRE 726.3.3 233U Capture-to-Absorption Ratio in Encapsulated Samples in the MSRE 72

7. SYSTEMS AND COMPONENTS DEVELOPMENT 737.1 Bubble Generator 737.2 Molten-Salt Steam Generator 73

7.2.1 Steam-Generator Industrial Program 747.2.2 Steam-Generator Tube Test Stand 74

7.3 Sodium Fluoroborate Circulating Test Loop 747.3.1 Corrosion-Product Deposition 747.3.2 Gas System Studies 75

7.4 MSBE Pumps 777.4.1 MSBE Salt Pump Procurement 777.4.2 MSBE Salt Pump Test Stand 787.4.3 ALPHA Pump 78


8. MSBR INSTRUMENTATION AND CONTROLS 838.1 Control System Analysis 838.2 Dynamic Analysis of MSBR Steam Generator 83

9. HEAT AND MASS TRANSFER AND THERMOPHYSICAL PROPERTIES 859.1 Heat Transfer 859.2 Thermophysical Properties 899.3 Mass Transfer to Circulating Bubbles 93

PART 3. CHEMISTRY

10. CHEMISTRY OF THE MSRE 9610.1 Composition of the MSRE Fuel Salt 9610.2 A Material Balance for Plutonium in the MSRE Fuel Salt 9810.3 Some Factors in Gas Behavior in the MSRE Fuel System 102

11. FISSION PRODUCT BEHAVIOR 10411.1 Examination of the Fourth Set Surveillance Specimens from the MSRE 104

11.1.1 Examination of Graphite 10411.1.2 Radiochemical Analyses of the Graphite 10411.1.3 Penetration of the Graphite by Uranium 10611.1.4 Radiochemical Analyses and Deposition of Fission Products on

Hastelloy N from the Core of the MSRE 10711.2 Samples from MSRE Pump Bowl 10711.3 Examination of Materials from MSRE Off-Gas Lines 10911.4 The Surface Tension of the MSRE Fuel and Flush Salts 10911.5 Niobium Reduction Potentials 11211.6 Noble-Metal Fission Product Chemistry 113

11.6.1 Synthesis and Stability of Molybdenum Fluorides 11311.6.2 Kinetics of MoF3 Disproportionation in Molten 2LiF-BeF2 11511.63 Mass Spectrometric Studies 11611.6.4 Infrared Spectroscopy 121

12. PROPERTIES OF THE ALKALI FLUOROBORATES 12212.1 Melting Points and Solid Transition Temperatures of Alkali Fluoroborates 12212.2 Densities and Molar Volumes of Molten Fluoroborates 12212.3 Predicted Volume Changes in Crystalline Alkali Fluoroborates 12312.4 Refractive Indices and Electronic Polarizabilities in Crystalline Alkali Fluoroborates 12412.5 Decomposition Pressures and Sº298 of LiBF4 12512.6 X-Ray Crystal Parameters of LiBF4 12712.7 Mixing Reactions of MSBR Fuel and Coolant Salts 12712.8 Phase Relations in the System NaF-KF-BF3 12812.9 Preparation of Pure NaBF4 12912.10 Attempted Synthesis of NaBF3OH 130

13. PHYSICAL CHEMISTRY OF MOLTEN SALTS 13113.1 Phase Relations in the System LiF-BeF2-CeF3 13113.2 Heterogeneous Equilibria Between Cerium-Containing Melts and Various Oxide Phases 13113.3 Liquidus Temperatures in the System LiF-BeF2-ThF4 13513.4 The Solubility of Thorium in Thorium Tetrafluoride 13513.5 Potentiometric Determination of the U4+/U3+ Ratio in Molten Fluorides 13513.6 Refinement of the UF3 Spectrum 13713.7 EMF Measurements with Concentration Cells with Transference in Molten Mixtures

of LiFand BeF2 13813.8 Improved Determination of Electrical Conductance of LiF-BeF2 (66-34 mole %) 14113.9 Electrical Conductivities of Low-Melting NaF-BeF2 Mixtures 14213.10 Viscosity of Molten Salts 14413.11 Density of Molten Fluorides of Reactor Interest 14513.12 Room-Temperature Densities and Estimated Density Change, Upon Melting, of MSBR

Fuel and Coolant Salts 146

14. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL REPROCESSING TECHNOLOGY 14914.1 Reductive Extraction of Protactinium at High Concentrations (2000 ppm Level)

from MSBR Fuel Solvent Salt (LiF-BeF2-ThF4, 72-16-12 mole %)into Molten Bismuth 149

14.2 The Separation of Zirconium from Uranium in Bismuth Solutions by Platinide Precipitation 15114.3 Bismuth-Magnesium Mixtures as Rare-Earth Extractants 15214.4 Reductive Extraction of Rare Earths from Molten LiF-BeF2-ThF4

(72-16-12 mole %) into Tin and Aluminum-Tin Mixtures at 600°C 15214.5 Extraction of Thorium from Processed MSBR Fuel Salt into Molten Lead 154

15. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS FOR MOLTEN-SALTREACTORS 156

15.1 Determination of Oxide in MSRE Fuel 15615.2 Voltammetric Determination of U(IV)/U(III) Ratios in MSRE Fuel 15615.3 Computer-Operated Voltammetric U(IV)/U(III) Ratio Determination 15715.4 Electroanalytical Studies in Molten Fluorides 15815.5 Spectral Studies of Superoxide Ion in Molten Fluoride Salts 15915.6 Hot-Cell Spectrophotometric Facility 16015.7 Removal of Oxide from NaBF4 16115.8 Determination of Bismuth in MSRP Salts 162

15.8.1 Emission Spectrography 16215.8.2 Inverse Polarography 162



16. MSRE SURVEILLANCE PROGRAM 16516.1 Removal and Examination of Surveillance Samples 16516.2 Properties of the Hastelloy N Surveillance Samples 168

17. GRAPHITE STUDIES 17117.1 Procurement of New Graphites 17117.2 Graphite Fabrication 17117.3 X-Ray Studies 17217.4 Electron Microscopy of Graphite 17417.5 Gas Impregnation of Graphite with Carbon 17417.6 Graphite Irradiations in HFIR 17517.7 The Energy Dependence of Neutron Damage in Graphite 17717.8 Fundamental Studies of Radiation Damage Mechanisms in Graphite 17917.9 Macroscopic Damage Models 180

18. HASTELLOY N 18218.1 Aging of Titanium-Modified Hastelloy N 18218.2 Statistical Treatment of Aging Data for Hastelloy N 18318.3 Development of a Modified Hastelloy N 18418.4 Electron Microscope Studies 19318.5 Corrosion Studies 195

18.5.1 Fuel Salts 19518.5.2 Fertile-Fissile Salts 19518.5.3 Blanket Salts 20018.5.4 Coolant Salts 20018.5.5 Corrosion Meter 20218.5.6 Corrosion Status 202

18.6 Forced Convection Loop (MSR-FCL-1) 20318.7 Steam Corrosion of Hastelloy N 205

19. SUPPORT FOR CHEMICAL PROCESSING 21019.1 Chemical Vapor-Deposited Coatings 21019.2 Development of Bismuth-Resistant Brazing Filler Metals for Joining Molybdenum 211

20. SUPPORT FOR COMPONENTS DEVELOPMENT PROGRAM 21320.1 Remote Welding Studies 213


21. MEASUREMENT OF DISTRIBUTION COEFFICIENTS IN MOLTEN-SALT-METAL SYSTEMS 21521.1 Extraction of Transuranium Elements from Single-Fluid MSBR Fuels 21521.2 Extraction of Rare Earths and Thorium from Single-Fluid MSBR Fuels 21621.3 Coprecipitation of Rare Earths with Thorium Bismuthide 21721.4 Dissolvability and Solubility of PuF3 in LiF-BeF2 (66-34 mole %) 219

22. FLOWSHEET ANALYSIS 22022.1 Isolation of Protactinium 220

22.1.1 Steady-State Performance for the Case of MSBR Fueled with Uranium 22022.1.2 Transient Performance for the Case of MSBR Fueled with Uranium 22122.1.3 Steady-State Performance for the Case of MSBR Fueled with Plutonium 224

22.2 Removal of Rare Earths from a Single-Fluid MSBR 22522.3 Stripping of ThF4 from Molten Salt by Reductive Extraction 22622.4 MSBR Processing Plant Material and Energy Balance Calculations 226

23. ENGINEERING DEVELOPMENT OF PROCESS OPERATIONS 22923.1 Reductive Extraction Engineering Studies 22923.2 Electrolytic Cell Development 230

23.2.1 Static Cell Experiments 23023.2.2 Flow Electrolytic Cell Facility 23323.2.3 Analysis of Mass Transfer in Electrolytic Cells 235

23.3 Salt-Metal Contactor Development 23623.4 Effect of Axial Mixing on Extraction Column Height 23823.5 Axial Mixing in Bubble Columns 240


25. DESIGN STUDIES FOR SALT PROCESSING 24425.1 Heat Transfer Through the Frozen Salt Walls of an Electrolytic Cell 24425.2 Design of a Continuous Salt Purification System 24425.3 Design and Preparation of 239PuF3 Capsules for Small Refueling Additions to the MSRE 245



INTRODUCTION xi

SUMMARY xiii



1.2.1 Reactivity Balance 51.2.2 Xenon Poisoning 61.2.3 Dynamics Testing 71.2.4 Operational Diagnosis by Noise Analysis 71.2.5 Tritium 91.2.6 Fission Product Distribution in the Fuel System 111.2.7 Graphite Samples Exposed in Fuel Pump 131.2.8 Evaluation of Leak in Primary System 141.2.9 Salt Transfer to the Overflow Tank 141.2.10 Radiation Heating 151.2.11 System Heat Balance 151.2.12 Heat Transfer in Primary Heat Exchanger 171.2.13 Thermal Cycle History 17

1.3 Equipment 181.3.1 Salt Samplers 181.3.2 Control Rods and Drives 201.3.3 Off-Gas Systems 201.3.4 Component Cooling System 221.3.5 Containment and Ventilation 221.3.6 Heaters and Electrical System 221.3.7 Oil Systems for Salt Pumps 231.3.8 Radiator and Main Blowers 23

1.4 Remote Maintenance 231.5 Final Shutdown and Standby Status 241.6 Preparations for Inspection 25

2. REACTOR ANALYSIS 262.1 Introduction 262.2 Extensions of MSRE Core Physics Calculations to the Use of XSDRN-CITATION Programs 262.3 Evaluation of Long-Term Reactivity Behavior During Operation with 235U 30

3. COMPONENT DEVELOPMENT 343.1 Freeze-Flange Thermal-Cycle Test 34


3.2 Pumps 353.2.1 Mark 2 Fuel Pump 353.2.2 Oil Pump Endurance Test 36

3.3 Development of Analytical Model for 135Xe Poisoning in the MSRE 37

4. INSTRUMENTS AND CONTROLS 394.1 MSRE Operating Experience 394.2 Control System Design 404.3 MSRE On-line Computer 40


5. DESIGN 415.1 Single-Fluid MSBR Design Study 415.2 MSBR Primary Salt Storage Tank 465.3 Startup and Shutdown Procedures 46

5.3.1 Startup Procedures 465.3.2 Normal Shutdown 48

5.4 Designs for First-Generation Molten-Salt Power Reactors 485.4.1 General 485.4.2 Large MSRE-Type Reactor 495.4.3 Spherical Reactor with Graphite Ball Bed 49

5.5 Bayonet-Tube Heat Exchangers 545.6 Distribution of Tritium in an MSBR 54


6.1.1 Single-Fluid MSBR Reference Design 586.1.2 Designs for First-Generation Molten-Salt Power Reactors 606.1.3 Reactivity Coefficients 636.1.4 Control Rod Worth 64

6.2 MSR Experimental Physics 656.2.1 Indication of Integrated Power by 235U Depletion 65

7. SYSTEMS AND COMPONENTS DEVELOPMENT 677.1 Molten-Salt Steam Generator 67

7.1.1 Steam Generator Industrial Program 677.1.2 Steam Generator Tube Test Stand 67

7.2 Sodium Fluoroborate Test Loop 697.2.1 Salt Leak from Pressure Transmitter 697.2.2 Gas-System Studies 70

7.3 MSBR Pumps 727.3.1 MSBE Salt Pump Procurement 727.3.2 MSBE Salt Pump Test Stand 727.3.3 ALPHA Pump 74


8. MSBR INSTRUMENTATION AND CONTROLS 798.1 Control System Analysis 79


PART 3. CHEMISTRY

10. CHEMISTRY OF THE MSRE 9310.1 Corrosion of the MSRE Fuel Salt Circuit 93

10.2 Relationship of the Distribution of 95Nb in the MSRE to the Presenceof Uranium Trifluoride in the Fuel Salt 96

10.3 Power Output of the MSRE Based on the Isotopic Composition of Plutonium 9810.4 Isotopic Composition of Uranium During 233U Operations 10010.5 Surface Tension and Wetting Behavior of the MSRE Fuel and Coolant Salts 100

11. FISSION PRODUCT BEHAVIOR 10411.1 Examination of the Fourth Set of Surveillance Specimens from the MSRE 104

11.1.1 Radiochemical Analyses of the Graphite 10411.1.2 Radiochemical Analyses of Fission Product Deposition on Metal 10811.1.3 Fission Product Distribution in the MSRE 110

11.2 Fission Product Distribution in MSRE Pump Bowl Samples 11111.3 Investigations of the Behavior of Fission Product Niobium 11811.4 Noble Metal Fission Product Chemistry 123

11.4.1 Introduction 12311.4.2 Synthesis 12411.4.3 Niobium and Molybdenum Fluoride Solutions in Molten Li2BeF4 12411.4.4 Mass Spectroscopy of Molybdenum and Ruthenium Fluorides 126

12. PROPERTIES OF THE ALKALI FLUOROBORATES 13312.1 Phase Equilibria in the Alkali Metal Fluoride-Metal Fluoroborate Binary Systems:

The System RbF-RbBF4 13312.2 Solubility of Na3CrF6 in Sodium Tetrafluoroborate Melts 13412.3 Preparation of Pure Sodium Tetrafluoroborate 13412.4 Investigation of Oxidation of Metals by Fluoroborate Coolant 13512.5 Boron Trifluoride Pressure over Fluoroborate Coolant Salt Admixed with MSBR Fuel Salt 13612.6 Heat Content of Alkali Metal Fluoroborates 138

13. PHYSICAL CHEMISTRY OF MOLTEN SALTS 14013.1 Equilibration of Rare-Earth-Containing Molten Fluorides with Various Solids 14013.2 The Oxide Chemistry of Plutonium in Molten Fluorides 14213.3 The CeF3-ThF4 System 14513.4 Equilibrium Phase Relationships in the System LiF-BeF2-CeF3 14713.5 An Investigation of Possible Polymorphic Transitions in Uranium Tetrafluoride 14813.6 Estimation of Activity Coefficients in LiF-BeF2-ThF4 Melts 14913.7 Estimation of Activity Coefficients of Alkaline Earths in Molten Bismuth

and as Chlorides or Fluorides 15313.8 Potentiometric Studies in Molten Fluorides 15413.9 Electrical Conductivities and Ionic Mobilities in the Molten LiF-BeF2 System 15613.10 Electrical Conductivities of Proposed MSBR Fuel Compositions in

the LiF-BeF2-ThF4 System 15913.11 Determination of Liquidus Temperatures in the LiF-BeF2 System from

EMF Measurements of Transference Cells 16113.12 Coordination Effects on U(IV) Spectra in Fluoride Melts 16513.13 Hydrogen Behavior in Molten-Salt Reactor Systems 16713.14 Crystal Structure of the Complex Fluoride (Na,Li)7Th6F31 168

14. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL REPROCESSING TECHNOLOGY 17114.1 Distribution of Cerium, Europium, and Strontium Between Bismuth and Lithium Chloride 17114.2 Extraction of Cesium from Lithium Chloride into Bismuth by

Reduction with Lithium at 650°C 17214.3 Removal of Chloride from Simulated MSBR Fuel Solvent by Reaction

with Anhydrous Hydrogen Fluoride 17314.4 Calculated Behavior of Sodium, Rubidium, and Cesium in the

Molten-Salt Breeder Reactor Reprocessing Plant 17414.5 Reduction of Uranium and Protactinium with Titanium 176

14.6 Bismuth-Gold Alloys as Extractants for Rare Earths and Thorium 17614.7 Bismuth Platinum Solutions for the Extraction of Fission Products from MSBR Salt 17614.8 Extraction of Cerium and Thorium from LiF-BeF2 (66-34 mole %) into Bismuth at 600°C 178

15. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS FORMOLTEN-SALT REACTORS 18015.1 Determination of Oxide in MSRE Salt 18015.2 Voltammetric Determination of [U3+]/[ΣU] Ratios in MSRE Fuel 18015.3 Spectral Studies of MSRE Salts 18015.4 Tritium in the Effluent Gases of the MSRE 18315.5 Reference Electrode Studies in Molten Fluorides 18415.6 Removal of Oxide from NaBF4 18515.7 A Preliminary Study of Volatile AlCl3 Complexes 185



16. MSRE SURVEILLANCE PROGRAM 18816.1 Properties of Hastelloy N Samples Removed from the MSRE 189

17. GRAPHITE STUDIES 20017.1 Fundamental Studies of Radiation Damage Mechanisms in Graphite 20017.2 Procurement of New Grades of Graphite 20117.3 General Physical Property Measurements 20117.4 Graphite Fabrication 203

17.4.1 Characterization of Materials 20317.4.2 Fabrication by Hot Pressing 20317.4.3 Fabrication by Isostatic Pressing 20417.4.4 Conclusions 205

17.5 Measurement of the Thermal Conductivity of Graphite 20517.6 X-Ray Studies 20717.7 Electron Microscopy of Graphite 20917.8 Gas Impregnation of Graphite 20917.9 HFIR Irradiation Program 21317.10 Irradiation Behavior of Pyrolytic Carbons 21517.11 Calculation of Lifetime and Induced Stresses in MSBR Graphite Cores 218

18. HASTELLOY N 22218.1 Aging of Modified Alloys 22218.2 Effect of Carbon and Titanium on Postirradiation Properties 22518.3 Effects of Irradiation at 760°C on the Creep-Rupture Properties of Modified Hastelloy N 22918.4 Electron Microscopy of Modified Hastelloy N Alloys 23118.5 Weldabdity of Commercial Alloys 23818.6 Corrosion Studies 240

18.6.1 Fuel Salts 24018.6.2 Fertile-Fissile Salts 24218.6.3 Blanket Salts 24218.6.4 Coolant Salts 24218.6.5 Summary of Corrosion Studies 247

18.7 Fluoroborate Purity Test 24718.8 Forced-Convection Loop MSR-FCL-1 247

18.8.1 Metallurgical Analysis 24818.8.2 Forced-Convection Loop MSR-FCL-2 251

18.9 Corrosion of Hastelloy N in Steam 252

19. SUPPORT FOR CHEMICAL PROCESSING 25319.1 Fabrication Development of Molybdenum Components 25319.2 Welding of Molybdenum 25419.3 Development of Bismuth-Resistant Brazing Filler Metals for Joining Molybdenum 25519.4 Compatibility of Structural Materials with Bismuth 25619.5 Chemical Vapor Deposited Coatings 25919.6 Scaling Resistance of Carbon Steels 261

20. SUPPORT FOR COMPONENTS DEVELOPMENT PROGRAM 26520.1 Remote Welding Development 26520.2 Support for Systems and Component Development 26520.3 Coated Bearing Specimens 271


21. FLOWSHEET ANALYSIS 27721.1 Rare Earth Removal Using the Metal Transfer Process 27721.2 Protactinium Isolation Using Fluorination-Reductive Extraction 27921.3 MSBR Processing by Fluorination-Reductive Extraction and the Metal Transfer Process 282

22. MEASUREMENT OF DISTRIBUTION COEFFICIENTS IN MOLTEN-SALT-METAL SYSTEMS 28922.1 Metal Transfer Process Studies 28922.2 Extraction of Barium, Rare Earths, and Thorium from Single-Fluid MSBR Fuels 29022.3 Solubility of Bismuth in Single-Fluid MSBR Fuel Salts 29222.4 Studies Involving BiF3 292

23. ENGINEERING DEVELOPMENT OF PROCESS OPERATIONS 29523.1 Reductive Extraction Engineering Studies 29523.2 Design of a Processing Materials Test Stand and the First Molybdenum

Reductive Extraction Equipment 29823.3 Bismuth-Salt Interface Detector 30023.4 Contactor Development: Pressure Drop, Holdup, and Flooding in Packed Columns 30223.5 Contactor Development: Axial Mixing in Packed Columns 30423.6 Axial Mixing in Open Columns 30723.7 Demonstration of the Metal Transfer Process for Removing Rare Earths 30923.8 Frozen-Wall Fluorinator Development 30923.9 Electrolytic Cell Development 311

23.9.1 Static Cell Experiments 31223.9.2 Flow Electrolytic Cell Facility 316


25. SYSTEM CALCULATIONS 32425.1 MSBR Processing Plant Material and Energy Balance Calculations 32425.2 Effect of Chemical Processing on the Nuclear Performance of an MSBR 325

26. CONTINUOUS SALT PURIFICATION SYSTEM 329

27. DESIGN AND PREPARATION OF 239PuF3 CAPSULES FOR SMALL REFUELINGADDITIONS TO THE MSRE 332



INTRODUCTION

SUMMARY


1. MSRE OPERATIONS 11.1 Chronological Account 11.2 Operations Analysis 2

1.2.1 Gamma Spectrometry 21.2.2 Noble-Metal Migration 21.2.3 Radiation Heating 41.2.4 Fluorine Evolution from Frozen Salt 4

2. COMPONENT DEVELOPMENT 62.1 Freeze-Flange Thermal Cycle Test 62.2 Pumps 6

2.2.1 Mark 2 Fuel Pump 62.2.2 Oil Pump Endurance Test 6


3. DESIGN 83.1 Single-Fluid 1000-MW(e) MSBR Design Study Report 83.2 Molten-Salt Demonstration Reactor Design Study 8

3.2.1 Introduction 83.2.2 General Description 93.2.3 Buildings and Containment 93.2.4 Reactor 163.2.5 Primary Heat Exchangers 183.2.6 Primary Drain Tanks 183.2.7 Fuel Salt Storage Tank 213.2.8 Discard Salt Storage Tanks 223.2.9 Steam System 24

3.3 Afterheat Temperatures in Empty MSBR Heat Exchangers 243.4 Industrial Study of 1000-MW(e) Molten-Salt Breeder Reactor 25


4.1.1 Fixed-Moderator Molten-Salt Reactor 264.2 MSR Experimental Physics 31

4.2.1 233U Capture-to-Absorption Ratio in the Fuel of the MSRE 31

5. SYSTEMS AND COMPONENTS DEVELOPMENT 355.1 Gaseous Fission Product Removal 35

5.1.1 Gas Separator 35

5.1.2 Bubble Generator 385.1.3 Water Test Loop 39

5.2 Molten-Salt Steam Generator 395.2.1 Steam Generator Industrial Program 395.2.2 Steam Generator Tube Test Stand (STTS) 405.2.3 Molten-Salt Steam Generator Technology Loop (SGTL) 405.2.4 Development Basis for Steam Generators Using Molten Salt as the Heat Source 40

5.3 Sodium Fluoroborate Test Loop 415.3.1 Water Addition Test 415.3.2 Conclusions 44

5.4 MSBR Pumps 445.4.1 MSBE Salt Pump Procurement 445.4.2 MSBE Salt Pump Test Stand 455.4.3 ALPHA Pump 45

5.5 Remote Welding 455.5.1 Operational Prototype Equipment 455.5.2 Cutting Development 455.5.3 Welding Development 475.5.4 External Interest 495.5.5 Design Studies 49

6. MSBR INSTRUMENTATION AND CONTROLS 51


PART 3. CHEMISTRY

8. FISSION PRODUCT BEHAVIOR 608.1 Noble Metal Fission Product Behavior 608.2 Short-Term Fission Product Deposition Tests 668.3 Fission Product Deposition on the Fifth Set of Graphite and

Hastelloy N Samples from the MSRE Core 688.3.1 Effect of Surface Roughness 688.3.2 Effect of Flow Conditions on Deposition 688.3.3 Comparison of Deposition of Noble Metal Fission Products on Graphite

and Hastelloy N 698.3.4 Concentration Profiles of Fission Products in Graphite 698.3.5 Electron Microscope Examination of Particles in the Gas Phase

Above Fuel Salt in the MSRE 708.4 A Possible Origin of Smokes and Mists Emitted by MSRE Fuel 708.5 Synthesis of Niobium Fluorides 718.6 Molybdenum and Niobium Fluoride Solutions in Molten Li2BeF4 718.7 Mass Spectroscopy of Niobium Fluorides 738.8 Raman Spectra of Crystalline MoF5 and MoF4 74

9. PROPERTIES OF THE ALKALI FLUOROBORATES 789.1 Solubility of BF3 Gas in Fluoride Melts 789.2 Studies of Hydrogen Evolution and Tritium Exchange in Fluoroborate Coolant Salt 799.3 Reaction of Water with the Sodium Fluoride-Sodium Tetrafluoroborate Eutectic 809.4 Raman Spectra of Molten NaBF4 and NaF-NaBF4 to 606°C 829.5 Electronic Polarizability of the Tetrafluoroborate Ion and Various Gaseous Halide

Molecules as Compared with the Free (Gaseous) Halide Ions 85

9.5.1 The Polarizability of the Tetrafluoroborate Ion 859.5.2 Test of a Recent Theoretical Set of Ion Polarizabilities 869.5.3 Effect of Interaction Between Halide Ions on Polarizability 87

10. PHYSICAL CHEMISTRY OF MOLTEN SALTS 8910.1 Liquidus Temperature of the Salt Mixture LiF-BeF2-ThF4 (70-15-15 mole %) 8910.2 Equilibrium Phase Relationships in the System LiF-BeF2-CeF3 8910.3 Phase Relationships in the System CeF3-ThF4 8910.4 The Instability of PuOF and the Solubility of Pu(III) in MSBR Solvent Salt 9110.5 Oxide, Chemistry of Protactinium in MSBR Fuel Solvent Salt 9210.6 Entropies of Molten Salts 9510.7 All-Metal Conductance Cell for Use in Molten Salts 9810.8 Glass Transition Temperatures in NaF-BeF2 Mixtures 9910.9 Correlations of Electrical Conductivities in Molten LiF-BeF2-ThF4 Mixtures 10110.10 Coordination Effects on U(IV) Spectra in Fluoride Melts 103

11. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL TECHNOLOGY 10611.1 Removal of Fluoride from Molten LiCl 10611.2 Distribution of Sodium and Potassium in the Metal Transfer Process at 650°C 10711.3 Removal of Lanthanides from Lithium Chlorides on Zeolites 10911.4 Zirconium Platinide as a Removal Agent for Rare Earths 110


12.1 Spectral Studies of MSRE Fuel Samples 11312.2 Spectral Studies of Actinide Ions in Molten Fluoride Salts 11412.3 Reference Electrode Studies in Molten Fluorides 11512.4 Kinetic Studies on the Ni/Ni(II) Couple in Molten LiF-BeF2-ZrF4 11512.5 Analytical Studies of NaBF4 Coolant Salt 11612.6 In-Line Chemical Analyses 118


13. EXAMINATION OF MSRE COMPONENTS 11913.1 Examination of Tubing from the MSRE Radiator 12013.2 Examination of Thermocouple Wells from the MSRE Coolant Circuit 126

14. GRAPHITE STUDIES 13414.1 Procurement of New Grades of Graphite 13414.2 General Physical Property Measurements 13514.3 Graphite Fabrication: Chemistry 13514.4 Measurement of Thermal Conductivity of Graphite 14114.5 X-Ray Studies 14114.6 Reduction of Graphite Permeability by Pyrolytic Carbon Sealing 14214.7 HFIR Irradiation Program 145

15. HASTELLOY N 14915.1 Influence of Titanium on the Strengthening of an Ni-Mo-Cr Alloy 14915.2 Effect of Composition on the Postirradiation Mechanical Properties of Modified Hastelloy N 15315.3 Comparison of Laboratory and Commercial Heats of Modified Hastelloy N 15615.4 Effect of Prior Aging on Irradiation Damage at 760°C 15915.5 Weldability of Commercial Alloys 16015.6 Mechanical Properties of Unirradiated Commercial Modified Alloys 16115.7 Electron Microscope Studies 16415.8 Corrosion Studies 165

15.8.1 Results of Thermal Convection Loop Tests 16615.8.2 Fertile-Fissile Salt 16815.8.3 Blanket Salt 16815.8.4 Coolant Salt 16815.8.5 Summary 171

15.9 Forced-Convection Loop, MSR-FCL-1 17315.9.1 Operations 17315.9.2 Cold Finger Corrosion Product Trap 17415.9.3 Metallurgical Analysis 17515.9.4 Forced-Convection Loop MSR-FCL-2 176

15.10 Corrosion of Hastelloy N in Steam 17815.11 Evaluation of Duplex Tubing for Use in Steam Generators 181

16. SUPPORT FOR CHEMICAL PROCESSING 18416.1 Construction of a Molybdenum Reductive Extraction Test Stand 18416.2 Fabrication Development of Molybdenum Components 18416.3 Welding of Molybdenum 18516.4 Development of Bismuth-Resistant Filler Metals for Brazing Molybdenum 18916.5 Compatibility of Structural Materials with Bismuth 18916.6 Chemically Vapor Deposited Coatings 195

16.6.1 Tungsten Coatings 19516.6.2 Molybdenum Coatings 197

16.7 Molybdenum Deposition from MoF6 197

17. FLOWSHEET ANALYSIS 19917.1 Protactinium Isolation Using Fluorination-Reductive Extraction 20017.2 Rare-Earth Removal Using the Metal Transfer Process 20117.3 Removal of Uranium from Fuel Salt by Oxide Precipitation 202

18. MEASUREMENT OF DISTRIBUTION COEFFICIENTS IN MOLTEN-SALT-METAL SYSTEMS 20418.1 Metal Transfer Process Studies 20418.2 Solubility of Neodymium in Li-Bi-Th Solutions 20718.3 Solubility of LaOCl in Molten LiCl 20818.4 Oxide Precipitation Studies 208


19. ENGINEERING DEVELOPMENT OF PROCESS OPERATIONS 21119.1 Reductive Extraction Engineering Studies 21119.2 Design of a Processing Materials Test Stand and the Molybdenum Reductive

Extraction Equipment 21219.3 Contactor Development: Pressure Drop, Holdup, and Flooding in Packed Columns 21319.4 Contactor Development: Axial Mixing in Packed Columns 21519.5 Axial Mixing in Open Bubble Columns 21619.6 Demonstration of the Metal Transfer Process for Rare-Earth Removal 21719.7 Development of a Frozen-Wall Fluorinator 21919.8 Electrolytic Cell Development 220




INTRODUCTION ix

SUMMARY xi


1. POSTOPERATION EXAMINATIONS 11.1 Outline of Program 11.2 Reactor Vessel and Core 21.3 Fuel Pump 61.4 Heat Exchanger 111.5 Leak at Freeze Valve FV-105 121.6 Other Examinations 121.7 Evaluation of Tools and Procedures 13

2. FURTHER INVESTIGATIONS 172.1 Test of Coolant Salt Flowmeter and Conclusions 172.2 Inventories of Residual Uranium and Plutonium 182.3 Search for Unrecovered 235U 20


3. DESIGN 213.1 Single-Fluid 1000-MWe MSBR Design Study Report 213.2 Molten-Salt Demonstration Reactor Design Study 22

3.2.1 Introduction 223.2.2 Addition of Third Salt-Circulation Loop 223.2.3 Salt Overflow and Gas Stripping Systems 243.2.4 Primary Drain Tank 243.2.5 Drain Valves for Salt Service 253.2.6 Heat Exchangers 253.2.7 Building and Containment 28

3.3 Initial Temperature Transients in Empty MSBR "Reference Design" MSBR Heat Exchangers 323.4 The Consequences of Tubing Failure in the MSBR Heat Exchanger 343.5 Tritium Distribution and Control in the MSBR 353.6 Industrial Study of 1000-MWe Molten-Salt Breeder Reactor 363.7 MSBE Design 36

3.7.1 General 363.7.2 MSBE Core Design 363.7.3 MSBE Primary Heat Exchanger Design 39


4.1.1 Single-Fluid MSBR Reference Design 414.1.2 Fixed-Moderator Molten-Salt Reactor 43

4.2 MSR Experimental Physics 454.2.1 HTLTR Lattice Experiments 45


5.1.1 Gas Separator and Bubble Generator 495.2 Gas System Test Facility 515.3 Molten-Salt Steam Generator 51

5.3.1 Steam Generator Industrial Program 525.3.2 Steam Generator Tube Test Stand (STTS) 525.3.3 Molten-Salt Steam Generator Technology Facility (SGTF) 525.3.4 Development Bases for Steam Generators Using Molten Salt as the Heat Source 52

5.4 Sodium Fluoroborate Test Loop 525.4.1 Pump Bowl and Rotary Element 535.4.2 BF3 Feed and Salt Level Bubbler Tube 55

5.5 Coolant Salt Technology Facility 575.6 MSBR Pumps 58

5.6.1 MSRE Mark 2 Fuel Pump 585.6.2 MSRE Salt Pump Inspection 585.6.3 ALPHA Pump 59

5.7 Remote Welding 595.7.1 Automatic Controls 595.7.2 Pipe Cleaning Tests 60

6. MSBR INSTRUMENTATION AND CONTROLS 616.1 Development of a Hybrid Computer Simulation Model of the MSBR System 61

6.1.1 Introduction 616.1.2 Steam Generator Model 61

7. HEAT AND MASS TRANSFER AND THERMOPHYSICAL PROPERTIES 647.1 Heat Transfer 647.2 Thermophysical Properties 67

7.2.1 Wetting Studies 677.2.2 Thermal Conductivity 69

7.3 Mass Transfer to Circulating Bubbles 697.3.1 Experiment 697.3.2 Theory 70

PART 3. CHEMISTRY

8. FISSION PRODUCT BEHAVIOR 738.1 Determination of Tritium and Hydrogen Concentrations in MSRE Pump Bowl Gas 73

8.1.1 Calibration Apparatus 748.1.2 Analysis for Hydrogen 758.1.3 Tritium Diffusion Studies 76

8.2 Examination of Deposits from the Mist Shield in the MSRE Fuel Pump Bowl 768.2.1 Tritium 82

8.3 Synthesis of Niobium Fluorides 858.4 Reaction Kinetics of Molybdenum and Niobium Fluoride in Molten Li2BeF4 Solutions 858.5 Mass Spectroscopy of Niobium Fluorides 86

9. COOLANT SALT CHEMISTRY AND TRITIUM CONTROL 889.1 Studies of Hydrogen Evolution and Tritium Exchange in Fluoroborate Coolant 889.2 Reaction of Sodium Fluoride-Sodium Tetrafluoroborate with Water 909.3 Identification of Corrosion Products in the Bubbler Tube of the Fluoroborate Test Loop 929.4 Mass Spectroscopy of Fluoroborate MSR Coolants 939.5 Spectroscopic Investigations of Hydrogen- and Deuterium-Containing Impurities

in NaBF4 and NaF-NaBF4 Eutectics 94

9.6 Raman Spectra of the High-Temperature Phase of Polycrystalline NaBF4 969.7 A New Method for Synthesis of NaBF3OH 989.8 Solubility of BF3 Gas in Fluoride Melts 989.9 Equilibrium Phase Relationships in the System RbF-RbBF4 1009.10 Activities in Alkali Fluoride-Fluoroborate Mixtures 1009.11 High-Temperature Crystal Structure and Volume of Sodium Tetrafluoroborate

and Related Compounds 1019.12 Hydrogen Permeation through Oxide-Coated Metals 103

10. PHYSICAL CHEMISTRY OF MOLTEN SALTS 10710.1 Thermodynamics of LiF-BeF2 Mixtures from EMF Measurements of Concentration Cells 10710.2 Equilibrium Phase Relationships in the System LiF-BeF2-CeF3 10910.3 Electrical Conductivity of Molten and Supercooled NaF-BeF2 (40-60'Mole %) 10910.4 Glass Transition Temperatures in the NaF-BeF2 System 11010.5 Raman Spectra of BeF4

2- in Molten LiF and NaF to 686°C 11210.6 Bubble Formation by Impingement of a Jet Stream on a Fluid Surface 11510.7 The Solubility of Hydrogen in Molten Salt 11510.8 Enthalpy of UF4 from 298 to 1400K 11710.9 Absorption Spectroscopy of Molten Fluorides: The Disproportionation

Equilibrium of UF3 Solutions 11810.10 The Oxide Chemistry of Pa4+ in the MSBR Fuel Solvent Salt 11910.11 The Redox Potential of Protactinium in MSBR Fuel Solvent Salt 12010.12 The Crystal Structures of Complex Fluorides 122

10.12.1 The Crystal Structure of CsU6F25 12210.12.2 The Crystal Structure of α-KTh6F25 12210.12.3 The Crystal Structure of Li2MoF6 12210.12.4 The Crystal Structure of RbTh3F13 12410.12.5 The Crystal Structure of Rb5Zr4F21 12510.12.6 Discussion 125

10.13 Noncrystalline BeF2 at 25°C: Structure and Vibrational Motion 12510.14 Relationshic between Entropy and Sonic Velocity in Molten Salts 12610.15 A Reference Electrode System for Use in Fluoride Melts 127

11. CHEMISTRY OF MOLTEN-SALT REACTOR FUEL TECHNOLOGY 12911.1 Extraction of Rubidium and Cesium from MSBR Fuel Solvent into Bismuth by

Reduction with Lithium at 650°C 12911.2 Distribution of Thorium between MSBR Fuel Solvent and Bismuth

Saturated with Nickel and Thorium at 650°C 13011.3 Bismuth-Manganese Alloys as Extractants for Rare Earths from MSBR Fuel Solvent 13111.4 Removal of Solutes from Bismuth by Fractional Crystallization 131


12.1 Electroanalytical Studies of Titanium(IV) in Molten LiF-NaF-KF (46.5-11.5-42.0 Mole %) 13412.2 Reference Electrode Studies in Molten NaBF4 13512.3 Electrochemical-Spectral Studies of Molten Fluoride Salt Solutions 13612.4 Spectral Studies of Molten Fluoride Salts 13612.5 Analytical Studies of the NaBF4 Coolant Salt 13712.6 In-Line Chemical Analysis 138


13. EXAMINATION OF MSRE COMPONENTS 13913.1 Examination of a Graphite Moderator Element 13913.2 Auger Analysis of the Surface Layer on Graphite Removed from the Core of the MSRE 143

13.2.1 Auger Electron Spectroscopy 144

13.2.2 Results and Discussion 14513.3 Examination of Hastelloy N Control Rod Thimble 14713.4 Examination of the Sampler Assembly 15013.5 Examination of a Copper Sample Capsule 15413.6 Examination of the Primary Heat Exchanger 15613.7 Examination of Freeze Valve 105 160

14. GRAPHITE STUDIES 16714.1 Graphite Irradiations in HFIR 16714.2 Graphite Fabrication 16914.3 Graphite Development – Chemistry 17014.4 Graphitization Study of a Lampblack-Pitch Carbon 17114.5 Reduction of Graphite Permeability by Pyrolytic Carbon Sealing 17314.6 Fundamental Studies of Radiation Damage Mechanisms in Graphite 17414.7 Lattice Dynamics of Graphite 176

15. HASTELLOY N 17915.1 Status of Laboratory Heat Postirradiation Evaluation 17915.2 Postirradiation Creep Testing of Hastelloy N 18015.3 The Unirradiated Mechanical Properties of Several Modified Commercial Alloys 18115.4 The Weldability of Several Modified Commercial Alloys 18515.5 Postirradiation Properties of Several Commercial Alloys 18815.6 Status of Development of a Titanium-Modified Hastelloy N 19215.7 Corrosion Studies 192

15.7.1 Fuel Salts 19415.7.2 Fertile-Fissile Salt 19615.7.3 Blanket Salt 19615.7.4 Coolant Salt 19615.7.5 Analysis of H2O Impurities in Fluoroborate Salts 197

15.8 Forced-Convection Loop Corrosion Studies 20215.8.1 Operation of Forced-Convection Loop MSR-FCL-1 20215.8.2 Metallurgical Analysis of MSR-FCL-1 20415.8.3 Forced-Convection Loop MSR-FCL-2 206

15.9 Retention of Tritium by Sodium Fluoroborate 21015.10 Support for Components Development Program 211

15.10.1 Metallurgical Examination of Inconel Bubbler Tube from PKP-1 Pump Loop 21115.11 Corrosion of Hastelloy N in Steam 216

16. SUPPORT FOR CHEMICAL PROCESSING 21816.1 Construction of a Molybdenum Reductive-Extractive Test Stand 21816.2 Fabrication Development of Molybdenum Components 21916.3 Welding Molybdenum 22016.4 Development of Bismuth-Resistant Filler Metals for Brazing Molybdenum 22116.5 Compatibility of Materials with Bismuth 22516.6 Chemically Vapor Deposited Coatings 23116.7 Molybdenum Deposition from MoF6 232


17. FLOWSHEET ANALYSIS 23517.1 Protactinium Isolation Using Fluorination and Reductive Extraction 23517.2 Combination of Discard Streams from the Protactinium Isolation System

and the Metal Transfer System 23717.3 Protactinium Isolation Using Oxide Precipitation 23717.4 Stripping of Rare-Earth Fission Products from LiC1 in the Metal Transfer System 24017.5 Importance of Uranium Inventory in an MSBR Processing Plant 240

18. PROCESSING CHEMISTRY 24218.1 Measurement of Distribution Coefficients in Molten-Salt-Metal Systems 24218.2 Solubilities of Thorium and Neodymium in Lithium-Bismuth Solutions 24418.3 Oxide Precipitation Studies 245

19. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 24919.1 Engineering Studies of the Metal Transfer Process for Rare-Earth Removal 24919.2 Design of the Third Metal Transfer Experiment 25419.3 Development of Mechanically Agitated Salt-Metal Contactors 25519.4 Reductive Extraction Engineering Studies 25619.5 Contactor Development: Pressure Drop, Holdup, and Flooding in Packed Columns 26019.6 Development of a Frozen-Wall Fluorinator 26219.7 Estimated Corrosion Rates in Continuous Fluorinators 26419.8 Axial Dispersion in Simulated Continuous Fluorinators 26519.9 Engineering Studies of Uranium Removal by Oxide Precipitation 26719.10 Design of a Processing Materials Test Stand and the Molybdenum

Reductive Extraction Equipment 267


ORGANIZATIONAL CHART 271



Contents


1. DESIGN 21.1 Molten-Salt Demonstration Reactor Design Study 2

1.1.1 General 21.1.2 Reactor Core 31.1.3 MSDR Off-Gas and Salt Pump-Back System 41.1.4 Drain Tank Cooling System 71.1.5 Drain Valve Cell 91.1.6 Drain Cell Catch Pan 9

1.2 Some Consequences of Tubing Failure in the MSBR Heat Exchanger 91.3 Side-Stream Processing of the MSBR Primary Flow for Xenon and/or Iodine Removal 101.4 MSBE Design 11

1.4.1 Reactor Core Power and Neutron Flux Distribution 111.4.2 Reactor Core Heat Removal 111.4.3 Maintenance Studies 14

1.5 MSBR Industrial Design Study 15

2. REACTOR PHYSICS 162.1 MSR Experimental Physics 16

2.1.1 HTLTR Lattice Experiments 162.2 Physics Analysis of MSBR 18

2.2.1 Neutron Irradiation Effects Outside the MSBR Core 182.2.2 MSBE Nuclear Characteristics 202.2.3 Fixed-Moderator Molten-Salt Reactor 21


3.1.1 Gas Separator and Bubble Generator 263.1.2 Bubble Formation and Coalescence Test 27

3.2 Gas System Test Facility 273.3 Off-Gas Systems 28

3.3.1 Off-Gas System for Molten-Salt Reactors 283.3.2 Computer Design of Charcoal Beds for MSR Off-Gas Systems 29

3.4 Molten-Salt Steam Generator 293.4.1 Steam Generator Industrial Program 293.4.2 Molten-Salt Steam Generator Technology Facility 293.4.3 Molten-Salt Steam Generator Test Proposals 30

3.5 Sodium Fluoroborate Test Loop 313.5.1 Inspection of PKP Pump Rotary Element 31

3.6 Coolant-Salt Technology Facility 343.7 MSBR Pumps 35

3.7.1 Salt Pumps for MSRP Technology Facilities 353.7.2 ALPHA Pump 353.7.3 Drain Tank Jet Pump System for MSDR 36

4. INSTRUMENTATION AND CONTROLS 384.1 Transient and Control Studies of the MSBR System Using a Hybrid Computer 384.2 MSRE Design and Operations Report, Part IIB, Nuclear and Process Instrumentation 384.3 Further Discussion of Instrumentation and Controls Development Needed for the

Molten-Salt Breeder Reactor 38


PART 2. CHEMISTRY

6. POSTOPERATIONAL EXAMINATION OF MSRE 466.1 Examination of Moderator Graphite from MSRE 46

6.1.1 Results of Visual Examination 466.1.2 Segmenting of Graphite Stringer 466.1.3 Examination of Surface Samples by X-ray Diffraction 476.1.4 Examination with a Gamma Spectrometer 476.1.5 Milling of Surface Graphite Samples 496.1.6 Radiochemical and Chemical Analyses of MSRE Graphite 49

6.2 Cesium Isotope Migration in MSRE Graphite 516.3 Fission Product Concentrations on MSRE Surfaces 546.4 Metal Transfer in MSRE Salt Circuits 55

7. HYDROGEN AND TRITIUM BEHAVIOR IN MOLTEN SALT 567.1 The Solubility of Hydrogen in Molten 2LiF·BeF2 567.2 Permeation of Metals by Hydrogen 577.3 Tritium Control in an MSBR 59

7.3.1 Mass Spectrometric Examination of Stability of NaBF3OH 597.3.2 The Thermal Stability of Nitrate-Nitrite Mixtures 59

7.4 Dissociating-Gas Heat Transfer Scheme and Tritium Control in Molten-Salt Power Systems 60

8. PROCESSING CHEMISTRY 628.1 The Oxide Chemistry of Pa4+ in Molten LiF-BeF2-ThF4 628.2 The Oxide Chemistry of Pa5+ in Uranium-Containing Molten LiF-BeF2-ThF4 648.3 Reductive Extraction Distributions of Barium and. Thorium Between Bismuth-Lead

Eutectic and Breeder Fuel Solvent 678.4 Removal of Cerium from Lithium Chloride by Zeolite 67

9. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS

FOR MOLTEN SALT REACTORS 699.1 In-Line Chemical Analysis of Molten Fluoride Salt Streams 699.2 Slotted Probe for In-Line Spectral Measurements 709.3 In-Line Determination of Hydrolysis Products in NaBF4 Cover Gas 719.4 Determination of Hydrogen in Fluoroborate Salts 739.5 Voltammetric and Electrolysis Studies of Hydroxide Ion in Molten NaBF4 749.6 Electroanalytical Studies in the NaBF4 Coolant Salt 759.7 Electroanalytical Studies of Ni(II) in Molten Fluoride Fuel Solvent 75

10. OTHER FLUORIDE RESEARCHES 7710.1 Absorption Spectroscopy of Molten Fluorides 77

10.1.1 The Disproportionation Equilibrium of UF3 Solutions 7710.1.2 Estimation of the Available F- Concentrations in Melts by

Measurement of UF4 Coordination Equilibria 77

10.2 Solubility of BF3 in Fluoride Melts 7810.3 Fluorides and Oxyfluorides of Molybdenum and Niobium 80

10.3.1 Mass Spectroscopy of Molybdenum Fluorides 8010.3.2 Mass Spectroscopy of Niobium Fluorides and Oxyfluorides 80

10.4 Electrical Conductivity of Molten and Supercooled Mixtures of NaF-BeF2 8110.5 Glass Transition Temperatures in the NaF-BeF2 System 8210.6 Enthalpy of Lithium Fluoroborate from 298-700K: Enthalpy and Entropy of Fusion 8510.7 Nonideality of Mixing in Li2BeF4LiI 86

11. EXAMINATION OF MSRE COMPONENTS 8911.1 Examination of Hastelloy N Components Exposed to Fuel Salt in the MSRE 8911.2 Examination of Components from In-Pile Loop 2 9411.3 Observations of Grain Boundary Cracking in the MSRE 9611.4 Examination of a Graphite Moderator Element 10611.5 Auger Analysis of the Surface Layer on Graphite Removed from the Core of the MSRE 107


12. GRAPHITE STUDIES 11112.1 The Irradiation Behavior of Graphite at 715°C 11212.2 Procurement of Various Grades of Carbon and Graphite 11412.3 X-Ray Studies 11612.4 Thermal Property Testing 11712.5 Helium Permeability Measurements on Various Grades of Graphite 11812.6 Reduction of Graphite Permeability by Pyrolytic Carbon Sealing 11912.7 The Magnified Topography of Graphite Sealed with Pyrolytic Carbon 12012.8 Reduction of Permeability by Fluid Impregnation 12112.9 Fundamental Studies of Radiation Damage Mechanisms in Graphite 122

13. HASTELLOY N 12513.1 Electron Microscopy Studies 125

13.1.1 Microstructures of Hf-Modified Hastelloy N Laboratory Melts 12513.1.2 Ni3Ti Precipitation in Ti-Modified Hastelloy N 12913.1.3 Strain-Induced Precipitation in Modified Hastelloy N 130

13.2 Mechanical Properties of Unirradiated Modified Hastelloy N 13213.3 Weldability of Several Modified Commercial Alloys 13213.4 Creep-Rupture Properties of Hastelloy N Modified with Niobium, Hafnium, and Titanium 13713.5 Corrosion Studies 138

13.5.1 Fuel Salts 13913.5.2 Fertile-Fissile Salt 14513.5.3 Blanket Salt 14513.5.4 Coolant Salt 145

13.6 Analysis of High-Level Probe from Sump Tank of PKP-1 15013.7 Forced-Convection Loop Corrosion Studies 150

13.7.1 Operation of Forced-Convection Loop MSR-FCL-1A 15013.7.2 Metallurgical Analysis of Forced-Convection Loop MSR-FCL-1A 15113.7.3 Operation of Forced-Convection Loop MSR-FCL-2 15113.7.4 Metallurgical Analysis of Forced-Convection Loop MSR-FCL-2 153


14. SUPPORT FOR CHEMICAL PROCESSING 16314.1 Construction of a Molybdenum Reductive-Extraction Test Stand 16314.2 Fabrication Development of Molybdenum Components 16614.3 Welding Molybdenum 16914.4 Development of Brazing Techniques for Fabricating the Molybdenum Test Loop 172

14.4.1 Resistance Furnace Brazing 17214.4.2 Induction Vacuum Brazing 17214.4.3 Induction Field Brazing 173

14.5 Compatibility of Materials with Bismuth 17314.6 Chemical Vapor Deposited Coatings 17614.7 Molybdenum Deposition from MoF6 177


15. FLOWSHEET ANALYSIS 17915.1 Cost Estimate for an MSBR Processing Plant 17915.2 Comparison of Costs for Alternate Off-Gas Treatment Methods for

an MSBR Processing Plant 18315.3 Effect of Noble-Metal and Halogen Removal Times on the Heat Generation

Rate in an MSBR Processing Plant 18615.4 Long-Term Disposal of MSBR Wastes 18615.5 Availability of Natural Resources Required for Molten Salt Breeder Reactors 189

16. PROCESSING CHEMISTRY 19116.1 Distribution of Lithium and Bismuth Between Liquid Lithium-Thorium-Bismuth Alloys

and Molten LiCl 19116.2 Mutual Solubilities of Thorium and Rare Earths in Liquid Bismuth 19316.3 Oxide Precipitation Studies 19616.4 Chemistry of Fuel Reconstitution 199

17. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 20217.1 Lithium Transfer During Metal Transfer Experiment MTE-2 20217.2 Operation of Metal Transfer Experiment MTE-2B 20417.3 Development of Mechanically Agitated Salt-Metal Contactors 20717.4 Design of the Third Metal Transfer Experiment 20917.5 Reductive Extraction Engineering Studies 21217.6 Development of a Frozen-Wall Fluorinator: Induction Heating Experiments 21417.7 Predicted Performance of Continuous Fluorinators 21717.8 Engineering Studies of Uranium Oxide Precipitation 22017.9 Design of a Processing Materials Test Stand and the Molybdenum Reductive

Extraction Equipment 22217.10 Development of a Bismuth-Salt Interface Detector 222

18. CONTINUOUS SALT PURIFICATION 226




1. DESIGN 21.1 Molten-Salt Demonstration Reactor Design Study 2

1.1.1 General 21.1.2 Reactor Core 21.1.3 Graphite Temperatures 61.1.4 Cell Cooling 8

1.2 Side-Stream Processing of MSBR Primary Flow for Iodine Removal 81.3 MSBR Industrial Design Study 91.4 MSBE Design 121.5 Bubble Behavior in the MSBR Primary Salt System 13

2. REACTOR PHYSICS 182.1 Experimental Physics 18

2.1.1 HTLTR Lattice Experiments 182.2 Physics Analysis of MSBR 21

2.2.1 Radiation Heating in MSR Pumps 212.2.2 MSBE Control-Rod Worths 222.2.3 Molten-Salt Converter Reactors Using Plutonium 23


3.1.1 Bubble Separator and Bubble Generator 283.1.2 Bubble Formation and Coalescence Test 293.1.3 Bubble Separator Analyses 29

3.2 Gas System Technology Facility 323.3 Molten-Salt Steam Generator Industrial Program 333.4 Coolant-Salt Technology Facility 333.5 Salt Pumps 34

3.5.1 Salt Pumps for MSRP Technology Facilities 343.5.2 ALPHA Pump 353.5.3 Molten-Salt Mixer, Laboratory Scale 37

4. INSTRUMENTATION AND CONTROLS 384.1 Transient and Control Studies of the MSBR System Using a Hybrid Computer 38

5. HEAT AND MASS TRANSFER AND PHYSICAL PROPERTIES 395.1 Heat Transfer 395.2 Wetting Studies 405.3 Mass Transfer to Circulating Bubbles 41

PART 2. CHEMISTRY

6. FISSION PRODUCT BEHAVIOR 456.1 Some Factors Affecting the Deposition Intensity of Noble-Metal Fission Products 456.2 Effects of Selected Fission Products on Hastelloy N, Nickel,

and Type 304L Stainless Steel at 650°C 506.3 Reaction of CoF3 with Tellurium 51

7. BEHAVIOR OF HYDROGEN AND ITS ISOTOPES 537.1 Solubility of Hydrogen in Molten Salt 537.2 Initial Tritium Chemistry in the Core of a Molten-Salt Reactor 537.3 Permeation of Hydrogen Through Metals at Low Pressures 547.4 Influence of Films or Coatings on Hydrogen Permeation Rates 567.5 Experiments on Hydrogen Evolution from Fluoroborate Coolant Salt 577.6 Apparatus for Infrared Spectral Studies of Molten Salts 597.7 Infrared Spectral Studies of the Chemical Behavior of BF3OH- and

BF3OD- Ions in Molten NaF-NaBF4 597.8 Thermal Stability of NaNO3, KNO3, NaNO2, and HITEC 62

8. FLUOROBORATE CHEMISTRY 638.1 Solubility of BF3 in Fluoride Melts 63

8.1.1 Reactor Applications 638.2 Free Energies of Formation of NaFeF3 and NaNiF3; Their Relationship

to the Corrosion of Hastelloy N by Fluoroborates 658.3 Preparation of Fused Sodium Fluoroborate for the Coolant Salt Technology Facility 68

9. PROTACTINIUM CHEMISTRY 709.1 Oxide Chemistry of Protactinium in MSBR Fuel Salt 709.2 Binary Solid Solutions of PaO2 and Other Actinide Dioxides and Their

Exchange Equilibria with Molten-Salt Reactor Fluorides 729.3. Ternary Solid Solutions of ThO2, PaO2, and UO2 74

10. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODSFOR MOLTEN-SALT REACTORS 77

10.1 In-Line Chemical Analysis of Molten Fluoride Salt Streams 7710.2 Theoretical Considerations of the Voltammetric In-Line Determination of Uranium(III) 8010.3 Electroanalytical Studies of Titanium(IV) in Molten LiF-BeF2-ZrF4 (65.4-29.6-5.0 Mole %) 8110.4 Electrochemical Studies of Bismuth(III) in Molten LiF-BeF2-ZrF4 at 500°C 8210.5 Voltammetry of Chromium(III) in Molten NaBF4-NaF (92-8 Mole %) 8210.6 Voltammetric and Hydrolysis Studies of Protonated Species in Molten NaBF4 8310.7 Determination of Hydrogen in NaF-NaBF4 Salts 8310.8 Spectral Studies of Molten Salts 84

11. OTHER MOLTEN-SALT RESEARCHES 8711.1 The Oxide Chemistry of Niobium in Molten LiF-BeF2 Mixtures 87

11.1.1 Equilibrations of Nb2O5 and BeO with Molten LiF-BeF2 Mixtures 8711.1.2 Equilibrations Involving Nickel Niobates in Molten Li2BeF4 89

11.2 The Reaction of MoF6 with Niobium 9111.3 Thermodynamics of LiF-BeF2 Mixtures 9511.4 Electrochemical Mass Transport in Molten Beryllium Fluoride-Alkali Fluoride Mixtures 9611.5 Electrical Conductance in Beryllium Fluoride Rich NaF-BeF2 Mixtures 9811.6 The Disproportionation Equilibrium of UF3 Solutions 9811.7 The Raman Spectra of Be2F7

3- and Higher Polymers of BerylliumFluorides in the Crystalline and Molten State 100

11.8 Raman Spectra of Molten and Crystalline Potassium Dichromate 10311.9 Nonideality of Mixing in the Systems Li2BeF4-LiI, Na2BeF4-NaI, and Cs2BeF4-CsI 106


12. INTERGRANULAR CRACKING OF STRUCTURAL MATERIALS EXPOSED TO FUEL SALT 10912.1 Examination of Hastelloy N Components from the MSRE 109

12.1.1 Freeze Valve 105 10912.1.2 Control Rod Thimble 11112.1.3 Sampler Cage Rod 11512.1.4 Mist Shield 116

12.2 Auger Analysis of the Surface Layers on Graphite from the Core of the MSRE 11712.3 Auger Analysis of the Surface of a Fractured Hastelloy N Sample 12212.4 Intergranular Corrosion of Hastelloy N 12312.5 Tube-Burst Experiments 12612.6 Cracking of Samples Electroplated with Tellurium 12812.7 Cracking of Hastelloy N Being Creep Tested in Tellurium Vapor 12812.8 Intergranular Cracking of Materials Exposed to Sulfur and Several Fission Product Elements 13412.9 Mechanical Properties of Hastelloy N Modified with Several Elements 13612.10 Status of Intergranular Cracking Studies 141

13. GRAPHITE STUDIES 144Introduction 144

13.1 Graphite Development 14413.2 Procurement of Various Grades of Carbon and Graphite 14913.3 Texture Determinations 14913.4 Thermal Property Testing 15013.5 Nominal Helium Permeability Parameters for Various Grades of Graphite 15113.6 Reduction of Helium Permeability of Graphite by Pyrolitic Carbon Sealing 15113.7 Characterization of Pyrocarbon Sealants for Graphite Using Reflected Light

and Scanning Electron Microscopes 155

14. HASTELLOY N 16114.1 Development of a Titanium-Modified Hastelloy N 16114.2 Alloys with Exceptional Strength 16314.3 Weldability of Commercial Alloys of Modified Hastelloy N 16614.4 Electron Microscope Studies 171

14.4.1 Intermetallic Precipitation in Hastelloy N 17214.4.2 Precipitation in New Commercial Alloys 17314.4.3 Modification of X-Ray Diffraction Techniques 173

14.5 Salt Corrosion Studies 17414.5.1 Fuel Salt 17414.5.2 Fertile-Fissile Salt 17714.5.3 Blanket Salt 17714.5.4 Coolant Salt 177

14.6 Forced-Convection Loop Corrosion Studies 17914.6.1 Operation of Loop MSR-FCL-1A 17914.6.2 Results from Loop MSR-FCL-1A 17914.6.3 Operation of Loop MSR-FCL-2 18014.6.4 Results from Loop MSR-FCL-2 180


15. SUPPORT FOR CHEMICAL PROCESSING 19215.1 Construction of a Molybdenum Reductive-Extraction Test Stand 19215.2 Fabrication Development of Molybdenum Components 19415.3 Welding of Molybdenum 19515.4 Development of Brazing Techniques for Fabricating the Molybdenum Test Loop 19515.5 Compatibility of Materials with Bismuth 197

15.5.1 Tantalum and T-111 19715.5.2 Graphite 19815.5.3 Tungsten-Coated Hastelloy N 19915.5.4 Molybdenum 199

15.6 Molybdenum Braze Alloy Compatibility 202


16. FLOWSHEET ANALYSIS 20416.1 Design Study and Cost Estimates of a Processing Plant for a 1000-MWe MSBR 20416.2 Multiregion Code for MSBR Processing Plant Flowsheet Calculations 205

17. PROCESSING CHEMISTRY 20717.1 Distribution of Lithium and Bismuth between Liquid Lithium-Bismuth Alloys

and Molten LiCl 20717.2 Solubility of Europium in Liquid Bismuth 20917.3 Integral Heats of Lithium-Bismuth Solutions 20917.4 Protactinium Oxide Precipitation Studies 21017.5 Chemistry of Fuel Reconstitution 212

18. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 21618.1 Lithium Transfer during Metal Transfer Experiment MTE-2 21618.2 Operation of Metal Transfer Experiment MTE-2B 21718.3 Installation, Testing, and Charging of Materials to the Third Metal Transfer Experiment 22118.4 Design of the Metal Transfer Process Facility 22418.5 Development of Mechanically Agitated Salt-Metal Contactors 22518.6 Reductive Extraction Engineering Studies 22718.7 Design of the Reductive-Extraction Process Facility 23018.8 Frozen-Wall Fluorinator Development 23018.9 Engineering Studies of Uranium Oxide Precipitation 23418.10 Design of a Processing Materials Test Stand and the

Molybdenum Reductive Extraction Equipment 23818.11 Development of a Bismuth-Salt Interface Detector 239




Introduction vii

Summary ix


1. DESIGN 21.1 Lead-Cooled MSBRs 21.2 MSBR Industrial Design Study 5

1.2.1 Drain Tank 51.2.2 Physics Calculations 101.2.3 Chemical Processing 11

1.3 Xenon Behavior in the MSBR Fuel Salt System 111.4 Hybrid Computer Simulation of the MSBR 13

2. REACTOR PHYSICS 142.1 Analysis of HTLTR-MSR Lattice Experiments 142.2 Nuclear Performance of Lead-Cooled Molten-Salt Reactors 142.3 Plutonium Use in Molten-Salt Reactors 16

2.3.1 Fuel for Molten-Salt Converter Reactors 162.3.2 Start-up of an MSBR on Plutonium Fuel 222.3.3 ROD Code Modifications 25


3.1.1 Bubble Separator and Bubble Generator 263.1.2 Bubble Formation and Coalescence Test 293.1.3 Mass Transfer to Circulating Bubbles 29

3.2 Gas Systems Technology Facility 303.3 Molten-Salt Steam Generator Industrial Program 303.4 Coolant-Salt Technology Facility (CSTF) 313.5 Salt Pumps 32

3.5.1 Salt Pumps for MSRP Technology Facilities 323.5.2 ALPHA Pump 33

4. HEAT TRANSFER AND PHYSICAL PROPERTIES 354.1 Heat Transfer 354.2 Thermal Conductivity 36

PART 2. CHEMISTRY

5. BEHAVIOR OF HYDROGEN AND ITS ISOTOPES 385.1 The Solubility of Hydrogen in Molten Salt 385.2 Hydrogen Permeation Through Metals 395.3 The Chemisorption of Tritium on Graphite 42

6. FLUOROBORATE CHEMISTRY 436.1 Solubility of BF3 in Molten LiF-BeF2-ThF4 436.2 Solubility of BF3 in MSBR Primary Salt Containing 8 Mole % NaF:

Some Safety Considerations 436.3 Corrosion of Hastelloy N by Fluoroborate Melts 44

7. BEHAVIOR OF SIMULATED FISSION PRODUCTS 477.1 Effects of Selected Fission Products on Metals 477.2 Stability and Volatility of Metal Tellurides 48

8. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS 508.1 In-Line Chemical Analysis of Molten Fluoride Salt Streams 508.2 Voltammetric Studies of Protonated Species in Molten NaBF4-NaF (92-8 mole %) 508.3 Infrared Spectral Studies of NaBF4-NaF 528.4 Studies of Protons in Molten NaBF4 528.5 Analysis of Coolant Cover Gas 538.6 Spectral Studies of Molten Salts 54

9. OTHER MOLTEN-SALT RESEARCH 569.1 The Disproportionation Equilibrium of UF3 Solutions in Graphite 569.2 EMF Studies of Oxide Equilibria in Molten Fluorides 579.3 The Lithium Fluoride-Tetrafluoroborate Phase Diagram 589.4 Chronopotentiometry Based on Diffusion of Mobile Nonelectroactive Species 59


10. INTERGRANULAR CRACKING OF STRUCTURAL MATERIALS EXPOSED TO FUEL SALT 6310.1 Cracking of Samples Electroplated with Tellurium 6310.2 Intergranular Cracking of Several Alloys When Exposed to Tellurium Vapor 6310.3 Mechanical Properties of Structural Materials Containing Strontium and Tellurium 6910.4 The Isothermal Diffusion of 127Te Tracer in Hastelloy N,

Ni-200 and Type 304L Stainless Steel Specimens 7010.5 Tube-Burst Experiments 7110.6 Strain Cycle Experiments 7610.7 Identification of Reaction Products from Tellurium-Structural-Material Interactions 79

10.7.1 Knudsen Cell Reactions 8110.7.2 Possible Tellurides in Hastelloy N 8210.7.3 Tellurides from Knudsen Cell Reactions 8310.7.4 Tellurides from Other Reaction Methods 8310.7.5 Summary 85

10.8 Auger Electron Spectroscopy of Intergranular Fracture Surfaces of Nickeland Hastelloy N Exposed to Tellurium Vapor at 700°C 8610.8.1 Method 8710.8.2 Nickel 8810.8.3 Hastelloy N 88

10.9 Design of an In-Reactor Experiment to Study Fission Product Effects on Metals 9010.9.1 Design Criteria 9010.9.2 Configuration 9110.9.3 Thermal Considerations 9110.9.4 Containment 9310.9.5 Fuel Salt Chemistry 93

11. GRAPHITE STUDIES 9511.1 The Irradiation Behavior of Graphite 9511.2 Procurement and Characterization of Various Grades of Graphite 10011.3 Characterization of ORNL Graphites 101

11.4 Graphite Fabrication 10311.5 Thermal Property Testing 10611.6 Reduction of Helium Permeability of Graphite by Pyrolytic Carbon Sealing 10711.7 Irradiation of Pyrocarbons 11111.8 Examination of Unirradiated and Irradiated Pyrocarbon Strips with

the Scanning Electron Microscope (SEM) 11111.9 Texture Determinations 113

12. HASTELLOY N 11712.1 Mechanical Properties of Several Commercial Heats of Modified Hastelloy N 11712.2 Irradiation of Hastelloy N in the HFIR 12012.3 Salt Corrosion Studies 124

12.3.1 Fuel Salt 12612.3.2 Fertile-Fissile Salt 12612.3.3 Blanket Salt 12712.3.4 Coolant Salt 12712.3.5 Corrosion of Type 304L Stainless Steel and Hastelloy N

by Mixtures of Boron Trifluoride, Air, and Argon 13212.3.6 Oxide Additions to Sodium Fluoroborate 134

12.4 Forced-Convection Loop Corrosion Studies 13512.4.1 Operation of Forced-Convection Loop MSR-FCL-1A 13512.4.2 Corrosion Results from Forced-Convection Loop MSR-FCL-1A 13512.4.3 Operation of Forced-Convection Loop MSR-FCL-2 13612.4.4 Corrosion Results from Forced-Convection Loop MSR-FCL-2 137

12.5 Corrosion of Hastelloy N in Steam 137

13. SUPPORT FOR CHEMICAL PROCESSING 14713.1 Construction of a Molybdenum Reductive-Extraction Test Stand 14713.2 Welding of Molybdenum 14713.3 Development of Brazing Techniques for Fabricating the Molybdenum Test Loop 14913.4 Compatibility of Materials with Bismuth and Bismuth-Lithium Solutions 151

13.4.1 Tantalum Alloys 15213.4.2 Molybdenum Alloys 15213.4.3 Graphite 152

PART 4. FUEL PROCESSING FOR MOLTEN-SALT REACTORS

14. FLOWSHEET ANALYSIS 15914.1 Multiregion Code for MSBR Processing Plant Calculations 159

15. PROCESSING CHEMISTRY 16015.1 Equilibria in Fused Salt-Liquid Alloy Systems 16015.2 Solubility of Thorium in Liquid Li-Pb Alloys 16215.3 Reductive Extraction of Titanium and Cesium 16315.4 Chemistry of Fuel Reconstitution 16415.5 Protactinium Oxide Precipitation Studies 165

16. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 16816.1 Operation of Metal Transfer Experiment MTE-3 16816.2 Design of the Metal Transfer Process Facility 17116.3 Development of Mechanically Agitated Salt-Metal Contactors 17116.4 Reductive-Extraction Engineering Studies 17316.5 Reductive-Extraction Processing Facility Development 17516.6 Design of a Processing Materials Test Stand and the Molybdenum

Reductive-Extraction Equipment 17716.7 Removal of Bismuth from MSBR Fuel Salt 178

16.8 Frozen-Wall Fluorinator Development 18016.9 Uranium Oxide Precipitation Studies 18216.10 Development of a Bismuth-Salt Interface Detector 183




INTRODUCTION vii

SUMMARY ix

PART 1. MSBR DESIGN, DEVELOPMENT, AND SAFETY

1. DESIGN AND SYSTEMS ANALYSIS 21.1 ORNL Study of MSR Designs 2

1.1.1 Plant and Equipment Studies 21.1.2 Neutronic Analysis 21.1.3 Xenon Behavior 3

1.2 Tritium Behavior in Molten-Salt Systems 31.2.1 Reactor Calculations 31.2.2 Studies of Loop Experiments 4

1.3 Molten-Salt Reactor Information System 5


2.1.1 Bubble Generator 62.1.2 Bubble Separator 62.1.3 Bubble Formation and Coalescence Test 62.1.4 Bubble Size Measurement 72.1.5 Mass Transfer to Circulating Bubbles 72.1.6 Bubble Generation Analysis 8

2.2 Molten-Salt Steam Generator Industrial Program 92.2.1 Resumption of the Conceptual Design Study 92.2.2 Preliminary Results 9

2.3 Gas Systems Technology Facility 102.4 Coolant-Salt Technology Facility 102.5 Forced Convection Loop (MSR-FCL-2 and 2b) 14

2.5.1 Introduction 142.5.2 Operation of MSR-FCL-2 with Fluoroborate 142.5.3 Post Run Inspections 142.5.4 Cleanup and Modifications 152.5.5 Purging the System and Adding Salt 152.5.6 Operation of MSR-FCL-2b with Fuel Salt 16

3. REACTOR SAFETY 183.1 Safety Events in MSBR 183.2 MSBR Neutronic Excursions 18

PART 2. CHEMISTRY

4. FUEL SALT CHEMISTRY 224.1 The Chemistry of Tellurium in Molten Li2BeF4 224.2 Exposure of Metallurgical Samples to Tellurium Vapor 224.3 Removal of Iodide from LiF-BeF2 Melts by HF-H2 Sparging:

Application to Iodine Removal from MSBR Fuel 234.4 Protactinium Oxide Precipitation Studies 244.5 Solubility of BF3 in Salts of Molten-Salt Reactor Interest 24

5. COOLANT SALT CHEMISTRY 255.1 Oxide and Hydroxide Chemistry of Fluoroborate Melts 255.2 Corrosion of Structural Alloys by Fluoroborate Melts 255.3 Evaluation of Fluoroborate and Alternate Coolants 265.4 Density and Viscosity of Several Molten Fluoride Mixtures 28

6. TRITIUM BEHAVIOR 306.1 Permeation of Hydrogen Isotopes Through Structural Metals 306.2 The Solubilities of Hydrogen, Deuterium, and Helium in Molten Li2BeF4 306.3 Chemisorption of Tritium on Graphite 30

7. OTHER RESEARCH 347.1 The Wetting of Graphite by Bismuth and Bismuth-Lithium Alloys

as Determined by the Sessile Drop Method 34

8. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS 358.1 In-Line Analysis of Breeder Fuel 358.2 Determination of Trivalent Uranium in Simulated MSRE Fuel 368.3 In-Line and Other Support Analyses for Circulating NaF-NaBF4 Coolant 378.4 Studies on the Electroreduction of Uranium(IV) in Molten LiF-BeF2-ZrF4 428.5 Electroanalytical Studies of Tellurium in Molten LiF-BeF2 -ZrF4

(65.6-29.4-5.0 mole %) 438.6 Electroanalytical Studies of Bismuth in Molten LiF-BeF2-ZrF4

(65.6-29.4-5.0-mole %) 438.7 Electroanalytical Studies in Molten NaBF4 448.8 Spectrophotometric Research 458.9 Spectral Studies of f-d and f-f Transitions of Pa(IV) in Molten LiF-BeF2-ThF4 458.10 Spectrophotometric Developments for Improved Analytical Methods for Fluoroborate

Coolant Systems 46

9. INORGANIC AND PHYSICAL CHEMISTRY 479.1 The Equilibrium of Dilute UF3 Solutions Contained in Graphite 479.2 Effects of Oxygen on the UF3 /UF4 Equilibrium 489.3 Porous Electrode Studies 499.4 Formation Free Energies and Activity Coefficients in Fuel Salt Mixtures 519.5 The Chemistry and Thermodynamics of Molten-Salt Reactor Fuels 519.6 Oxide Chemistry of Niobium(V) in Molten LiF-BeF2 Mixtures 53


10. DEVELOPMENT OF MODIFIED HASTELLOY N 5710.1 Procurement of New Test Materials 5710.2 Weldability of Commercial Alloys of Modified Hastelloy N 5710.3 Mechanical Properties of Modified Hastelloy N 6110.4 Transmission Electron Microscopy of Ti-Modified Hastelloy N Alloys 6210.5 Salt Corrosion Studies 69

10.5.1 Fuel Salt Thermal Convection Loop Results 6910.5.2 Coolant Salt Thermal Convection Loop Results 7410.5.3 Blanket Salt Thermal Convection Loop Results 7510.5.4 Status of Thermal Convection Loop Program with Fuel and Coolant Salts 7510.5.5 Forced Circulation Loop Results 7510.5.6 Surveillance Specimens from the Coolant-Salt Technology Facility 77

10.6 Corrosion of Hastelloy N and Other Alloys in Steam 7710.7 Intergranular Cracking of Alloys Exposed to Tellurium 7910.8 Chemistry of Salt-Metal-Tellurium System 7910.9 Auger Observations Relative to Intergranular Cracking 80

10.9.1 Fracture Surface Analysis 8110.9.2 High Temperature Surface Studies 81

10.10 In-Reactor Fueled Experiments 8110.10.1 Design 8210.10.2 Calculated Operation and Test Conditions 8210.10.3 Preliminary Operating Data 84

11. FUEL PROCESSING MATERIALS DEVELOPMENT 8611.1 Static Capsule Tests of Graphite with Bismuth and Bismuth-Lithium Solutions 8611.2 Thermal Convection Loop Tests of Molybdenum, Tantalum, and Graphite in

Bismuth-Lithium Solution 89

12. GRAPHITE STUDIES 9212.1 Property Changes in Near-Isotropic Grades of Graphite Irradiated at 715°C to Fluences

as High as 4.2x1022 neutrons/cm2 9212.1.1 Materials 9212.1.2 Testing 9412.1.3 Property Changes as Functions of Fluence 9512.1.4 Conclusions 95


13. PROCESSING CHEMISTRY 10013.1 Chemistry of Fluorination and Fuel Reconstitution 10013.2 Equilibria in Fused Salt-Liquid Alloy Systems 101

14. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 10214.1 Examination of Equipment from Metal Transfer Experiment MTE-3 10214.2 Installation of Metal Transfer Experiment MTE-3B 11214.3 Design of the Metal Transfer Process Facility 11414.4 Salt-Metal Contactor Development: Experiments with a Mechanically Agitated

Nondispersing Contactor in the Salt-Bismuth Flow-through Facility 11414.5 Salt-Metal Contactor Development: Experiments with a Mechanically Agitated

Nondispersing Contactor Using Water and Mercury 11914.5.1 Theory 11914.5.2 Experimental Apparatus 12114.5.3 Results and Conclusions 121

14.6 Continuous Fluorinator Development: Autoresistance Heating Test AHT-3 12214.6.1 Experimental Equipment and Procedure 12214.6.2 Experimental Results 12414.6.3 Distribution of Current Densities in the Autoresistance Heating Equipment 124

14.7 Fuel Reconstitution Development: Design of a Fuel Reconstitution Engineering Experiment 12714.8 Performance of Open Bubble Columns 129

14.8.1 Axial Dispersion in Open Bubble Columns 13014.8.2 Mass Transfer Rates in Open Bubble Columns 130

14.9 Conceptual Design of an MSBR Processing Engineering Laboratory 132

PART5. SALT PRODUCTION

15. PRODUCTION OF FLUORIDE-SALT MIXTURES FOR RESEARCHAND DEVELOPMENT PROGRAM 134



Introduction vii

SUMMARY ix

PART 1. MSBR DESIGN, DEVELOPMENT, AND SAFETY

1. DESIGN AND SYSTEMS ANALYSIS 31.1 Tritium Behavior in Molten-Salt Systems 3

1.1.1 MSBR Tritium Studies 31.1.2 Coolant Salt Technology Facility Calculations 11

1.2 Neutronic Analyses 141.3 High-Temperature Design 15

1.3.1 Analytical Investigation of the Applicability of Simplified Ratchetting andCreep-Fatigue Rules to Reactor System Component Geometries 15

1.3.2 Inelastic Analyses of MSR Piping Subjected to Internal Pressure andTransient Temperature Cycles 21

2. SYSTEMS AND COMPONENTS DEVELOPMENT 232.1 Molten-Salt Steam Generator Industrial Program 232.2 Gas-Systems Technology Facility 23

2.2.1 General 232.2.2 Mark II Pump 242.2.3 Densitometer 25

2.3 Coolant-Salt Technology Facility 252.4 Forced-Convection Loops 29

2.4.1 Operation of MSR-FCL-2b 292.4.2 MSR FCL-3 and FCL4 31

3. SAFETY STUDIES 323.1 Salt-Spill Accidents 32

3.1.1 Potential Causes 323.1.2 Direct Consequences 343.1.3 Deferred Consequences 35

PART 2. CHEMISTRY

4. FUEL-SALT CHEMISTRY 374.1 Tellurium Deposition on Hastelloy N Surfaces in an MSBR 374.2 Exposure of Metallurgical Samples to Tellurium Vapor 404.3 Effect of Oxygen on the UF3/UF4 Equilibrium in Molten Fluoride Solutions 414.4 The Uranium Tetrafuoride-Hydrogen Equilibrium in Molten Fluoride Solutions 434.5 Porous-Electrode Studies 44

5. COOLANT-SALT CHEMISTRY 475.1 Chemistry of Sodium Fluoroborate 475.2 Corrosion of Structural Alloys by Fluoroborates 49

5.2.1 Thermodynamics of Cr(III) in Fluoroborate 49

5.2.2 Metal Boride Formation 505.2.3 Corrosion of Nickel 51

6. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS 526.1 In-line Analysis of Molten MSBR Fuel 526.2 Electroanalytical Studies of Bismuth in Molten LiF-BeF2 -ZrF4 566.3 Electroanalytical Studies in Molten NaBF4-NaF 57


7. DEVELOPMENT OF MODIFIED HASTELLOY N 607.1 Procurement and Fabrication of Experimental Alloys 60

7.1.1 Production Heats 607.1.2 Semiproduction Heats 637.1.3 Laboratory Heats 66

7.2 Weldability of Commercial Alloys of Modified Hastelloy N 687.3 Stability of Various Titanium-Modified Hastelloy N Alloys 717.4 Mechanical Properties of Titanium-Modified Hastelloy N Alloys in the Unirradiated Condition737.5 Postirradiation Mechanical Properties of Modified Hastelloy N 797.6 Microstructural Analysis of Titanium-Modified Hastelloy N 83

7.6.1 Microstructure of Aged 503 and 114 Alloys 837.6.2 X-Ray Analysis of Precipitates 847.6.3 Irradiation and Creep Testing 847.6.4 Microstructure of Irradiated 503 and 114 Alloys 85

7.7 Salt Corrosion Studies 907.7.1 Status of Thermal-Convection Loop Program 907.7.2 Fuel Salt Thermal-Convection Loop Results 917.7.3 Forced-Circulation Loop Results 917.7.4 Coolant-Salt Technology Facility Results 947.7.5 Static Pot Tests 94

7.8 Corrosion of Hastelloy N and Other Alloys in Steam 947.9 Development of a Tellurium-Delivery System for a Representative Tellurium-Corrosion

Screening Test Method 1027.10 Reactions of Tellurium with Nickel at Low Tellurium Activities 1027.11 Surface- and Grain-Boundary Studies Related to Hastelloy N Grain-Boundary Embrittlement 104

7.11.1 Development of Improved Techniques 1047.11.2 High Temperature Studies of the Behavior of Tellurium in and on

Experimental Alloys 1047.12 Identification of Reaction Layers on Hastelloy N Exposed to Nickel Tellurides 105

7.12.1 Metallographic Examination 1057.12.2 Electron Microprobe Analysis 1057.12.3 X-Ray Diffraction Analysis 1097.12.4 Conclusions 109

7.13 Examination of Hastelloy N Specimens Exposed to Tellurium 1097.14 Operation and Analysis of TeGen-1 119

7.14.1 Operating History of TeGen-1 1197.14.2 Data Analysis for TeGen-1 1197.14.3 Future Irradiations 123

7.15 Examination of TeGen-1 123

8. FUEL PROCESSING MATERIALS DEVELOPMENT 1378.1 Static Capsule Tests of Graphite with Bismuth and Bismuth-Lithium Solutions 1378.2 Thermal Convection Loop Tests 1408.3 Tests of Oxidation-Resistant Coatings on Mild Steel Pipe 141

PART 4. FUEL PROCESSING FOR MOLTEN-SALT BREEDER REACTORS

9. CHEMISTRY OF FLUORINATION AND FUEL RECONSTITUTION 150

10. ENGINEERING DEVELOPMENT OF PROCESS OPERATIONS 15210.1 Installation of Metal Transfer Process 15210.2 Salt-Metal Contactor Development: Experiments with a Mechanically Agitated

Nondispersing Contactor in the Salt-Bismuth Flow-through Facility 15210.3 Salt-Metal Contactor Development: Experiments with a Mechanically Agitated

Nondispersing Contactor Using Water and Mercury 15710.3.1 Theory 15810.3.2 Experimental Results 15910.3.3 Polaric Determination of Mass-Transfer Coefficients 160

10.4 Continuous Fluorinator Development 16210.4.1 Autoresistance Ideating Test AHT-3 16210.4.2 Design of Equipment for Autoresistance Heating Test AHT-4 163

10.5 Fuel-Reconstitution Development: Installation of Equipment for aFuel-Reconstitution Engineering Experiment 165

10.6 Mass-Transfer Rates in Open Bubble Columns 17410.6.1 Experimental 17610.6.2 Effect of Liquid Velocity on KLa]d 17810.6.3 Effect of Viscosity on KLa]d 17810.6.4 Analysis of Previous Data 17810.6.5 Correlation of Column Parameters 18010.6.6 Conclusions 182

10.7 Conceptual Design of MSBR Fuel Processing Engineering Center 182

PART 5. SALT PRODUCTION

11. PRODUCTION OF FLUORIDE-SALT MIXTURES FOR RESEARCH AND DEVELOPMENT 184




SUMMARY

PART 1 - MSBR DESIGN AND DEVELOPMENT

1. SYSTEMS AND ANALYSIS 21.1 Tritium Behavior in Molten Salt-Systems 2

1.1.1 MSBR Calculations 21.1.2 Coolant Salt Technology Facility 3

1.2 Xenon Behavior in MSBR 81.3 Neutronic Analysis 9

1.3.1 MSBR Studies 91.3.2 TeGen Capsules 12

1.4 High-Temperature Design Methods 12

2. SYSTEMS AND COMPONENTS DEVELOPMENT 162.1 Gas-Systems Technology Facility 16

2.1.1 Cavitation and Salt-Pump Shaft Oscillations 162.1.2 Salt-Pump Performance Data and Calibration of Variable-Flow Restrictors 182.1.3 Salt-Pump Fountain Flow 192.1.4 Densitometer Studies 22

2.2 Coolant-Salt Technology Facility (CSTF) 222.2.1 Loop Operation 222.2.2 Salt Mist Test 232.2.3 Tritium Experiments 24

2.3 Forced Convection Loops 262.3.1 Operation of MSR FCL-2b 262.3.2 Design and Construction of FCL-3 and FCL4 27

PART 2. CHEMISTRY

3. FUEL SALT CHEMISTRY 293.1 Compounds in the Lithium-Tellurium System 293.2 Spectroscopy of Tellurium Species in Molten Salts 303.3 The Uranium Tetrafluoride-Hydrogen Equilibrium in Molten Fluoride Solutions 313.4 Porous Electrode Studies in Molten Salts 323.5 Fuel Salt-Coolant Salt Interaction Studies 343.6 Lattice and Formation Enthalpies of First-Row Transition Metal Fluorides 37

4. COOLANT SALT CHEMISTRY 414.1 Chemistry of Sodium Fluoroborate 414.2 Corrosion of Structural Alloys by Fluoroborates 42

5. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS 445.1 In-line Analysis of Molten MSBR Fuel 445.2 Tritium Addition Experiments in the Coolant-Salt Technology Facility 455.3 Electroanalytical Studies of Iron(II) in Molten LiF-BeFZ-ThF4 (72-16-12 mole %) 475.4 Voltammetric Studies of Tellurium in Molten LiF-BeFZ-ThF4 (72-16-12 mole %) 48


6. DEVELOPMENT OF MODIFIED HASTELLOY N 526.1 Development of a Molten-Salt Test Facility 526.2 Procurement and Fabrication of Experimental Alloys 65

6.2.1 Production Heats of 2% Ti-Modified Hastelloy N 656.2.2 Semiproduction Heats of 2% Ti-Modified Hastelloy N Containing Niobium 69

6.3 Weldability of Commercial Alloys of Modified Hastelloy N 696.4 Stability of Various Modified Hastelloy N Alloys in the Unirradiated Condition 746.5 Mechanical Properties of Titanium-Modified Hastelloy N Alloys in the Unirradiated Condition786.6 Postirradiation Creep Properties of Modified Hastelloy N 826.7 Microstructural Analysis of Titanium-Modified Hastelloy N 84

6.7.1 Microstructural Analysis of Alloys 503 and 114 856.7.2 Homogeneous Hastelloy N Alloys 88

6.8 Salt Corrosion Studies 916.8.1 Fuel Salt Thermal Convection Loops 936.8.2 Fuel Salt Forced Circulation Loop 946.8.3 Coolant Salt Thermal Convection Loops 94

6.9 Corrosion of Hastelloy N and Other Alloys in Steam 976.10 Observations of Reactions in Metal-Tellurium-Salt Systems 1006.11 Operation of Metal-Tellurium-Salt Systems 101

6.11.1 Tellurium Experimental Pot Number 1 1016.11.2 Chromium Telluride Solubility Experiment 1026.11.3 Tellurium Experimental Pot Number 2 103

6.12 Grain Boundary Embrittlement of Hastelloy N by Tellurium 1036.13 X-Ray Identification of Reaction Products of Hastelloy N

Exposed to Tellurium-Containing Environments 1076.14 Metallographic Examination of Samples Exposed to Tellurium-Containing Environments 1086.15 Examination of TeGen-1 119

6.15.1 Metallographic Observations 1236.15.2 Chemical Analyses for Tellurium 124

6.16 Salt Preparation and Fuel Pin Filling for TeGen-2 and -3 131

7. FUEL PROCESSING MATERIALS DEVELOPMENT 1327.1 Static Capsule Tests of Graphite with Bismuth and Bismuth-Lithium Solutions 1327.2 Thermal Gradient Mass Transfer Test of Graphite in a Molybdenum Loop 133

7.2.1 Weight Changes 1337.2.2 Compositional Changes 1337.2.3 Microstructural Changes 1377.2.4 Discussion of Results 137


8. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 1428.1 Metal Transfer Process Development 142

8.1.1 Addition of Salt and Bismuth Phases to Metal Transfer Experiment MTE-3B 1438.1.2 Run Nd-1 1448.1.3 Run Nd-2 1458.1.4 Discussion of Results 145

8.2 Salt-Bismuth Contactor Development 1478.2.1 Experiments with a Mechanically Agitated Nondispersing Contactor

in the Salt-Bismuth Flowthrough Facility 148 8.2.2 Experiments with a Mechanically Agitated Nondispersing

Contactor Using Water and Mercury 1498.3 Continuous Fluorinator Development 152

8.3.1 Installation and Initial Operation of Autoresistance Heating Test AHT-4 1528.3.2 Design of a Continuous Fluorinator Experiment Facility (CFEF) 1558.3.3 Fluorine Disposal System for Bldg. 7503 1568.3.4 Frozen Wall Corrosion Protection Demonstration 156

8.4 Fuel Reconstitution Engineering Development 1578.4.1 Instrumentation for Analyzing Reaction Vessel Off-Gases 1588.4.2 Design of the Second Fuel Reconstitution Engineering Experiment 160

8.5 Conceptual Design of a Molten-Salt Breeder Reactor Fuel Processing Engineering Center 161

PART5. SALT PRODUCTION

9. PRODUCTION OF FLUORIDE SALT MIXTURES FOR MSR PROGRAMRESEARCH AND DEVELOPMENT 163

9.1 Quantities of Salt Produced 1639.2 Operating Experience in 12-in.-diam Reactor 163

9.2.1 Charging and Melting of Raw Materials 1649.2.2 Hydrofluorination and Hydrogen Reduction 166

9.3 Summary 166




INTRODUCTION vii

SUMMARY ix


1. SYSTEMS AND ANALYSIS 21.1 TRITIUM BEHAVIOR IN THE COOLANT-SALT TECHNOLOGY FACILITY 2

1.1.1 Analysis of Experiments TI and T2 21.1.2 Analysis of Experiment T3 31.1.3 Analysis of Experiment T4 5

1.2 NEUTRONIC ANALYSIS 71.2.1 Cross Section Processing for MSBR Calculations 71.2.2 MSBR Performance Calculations 91.2.3 Helium Production in the MSBR Vessel 91.2.4 Production of 232U in the MSBR 101.2.5 Neutronic Analyses of TeGen Experiments 12

1.3 HIGH-TEMPERATURE DESIGN METHODS 121.3.1 Circular Cylindrical Shells 131.3.2 Nozzle-to-Spherical Shell Attachment 131.3.3 Nozzle-to-Cylinder Intersection 131.3.4 Inelastic Analyses of MSR Piping Subjected to Internal Pressure

and Transient Temperature Cycles 13

2. SYSTEMS AND COMPONENTS DEVELOPMENT 152.1 GAS-SYSTEMS TECHNOLOGY FACILITY 152.2 COOLANT SALT TECHNOLOGY FACILITY 16

2.2.1 Loop Operation 162.2.2 Tritium Tests 162.2.3 Equipment Modifications 18

2.3 FORCED CONVECTION LOOPS 192.3.1 Operation of MSR-FCL-2b 192.3.2 Heat Transfer Studies in MSR-FCL-2b 212.3.3 Design and Construction of FCL-3 and FCL-4 22

PART 2. CHEMISTRY

3. FUEL-SALT CHEMISTRY 243.1 Solubility of Lithium Tellurides in Fluoride Melts 243.2 Spectroscopy of Telluride Species in Molten Salts 273.3 Decomposition Pressure of LiTe3 283.4 Porous Electrode Studies in Molten Salts - Electrochemistry of Tellurium

in the LiCl-KCl Eutectic System 293.5 The Uranium Tetrafluoride-Hydrogen Equilibrium in Molten Fluoride Solutions 29

4. COOLANT-SALT CHEMISTRY 324.1 Hydrolytic Behavior of Na3B3F6O3 32

4.2 Vapor Density Studies in the System BF3-H2O 34

5. DEVELOPMENT AND EVALUATION OF ANALYTICAL METHODS 365.1 In-line Analysis of MSBR Fuel 365.2 Tritium Addition Experiments in the Coolant-Salt Technology Facility 365.3 Electrochemical Studies of Tellurium in Molten L1F-BeF2-ThF4 (72-16-12 mole %) 385.4 Electrochemical Studies of Oxygenated Species in Molten Fluorides 39


6. DEVELOPMENT OF MODIFIED HASTELLOY N 426.1 Procurement and Fabrication of Experimental Alloys 42

6.1.1 Production Heats of 2% Titanium-Modified Hastelloy N 426.1.2 Semiproduction Heats of 2% Titanium-Modified Hastelloy N

that Contain Niobium 456.2 Stability of Various Modified Hastelloy N Alloys in the Unirradiated Condition 456.3 Mechanical Properties of Modified Hastelloy N Alloys in the Unirradiated Condition 476.4 Postirradiation Creep Properties of Modified Hastelloy N 526.5 Microstructural Analysis of Modified Hastelloy N 59

6.5.1 Production of 2% Titanium-Hastelloy N Alloys with Uniform Carbide Distribution 596.5.2 Carbon Behavior in Ni-Mo-Cr-Ti Alloys 70

6.6 Salt Corrosion Studies 756.6.1 Thermal Convection Loop Results 766.6.2 Forced Circulation Loop Results 77

6.7 Corrosion of Hastelloy N and Other Alloys in Steam 806.8 Vapor Pressure Measurements of Metal Tellurides 856.9 Operation of Metal-Tellurium-Salt Systems 86

6.9.1 Tellurium Experimental Pot No. 1 866.9.2 Chromium Telluride Solubility Tests 876.9.3 Tellurium Screening Test 876.9.4 Ni3Te2 Capsule Test 876.9.5 Chromium-Tellurium-Uranium Interaction Experiment 87

6.10 Examination of a Hastelloy N Foil Sample Embrittled in the Molten-Salt Reactor Experiment 886.10.1 Sample History 886.10.2 Sample Fracture and Analysis Techniques 886.10.3 Observations 896.10.4 Discussion of Observations 93

6.11 High-Resolution Fractography of Hastelloy N Alloys Exposed to Tellurium 956.12 Metallographic Examination of Samples Exposed to Tellurium-Containing Environments 1006.13 Salt-Tellurium Creep Studies 1216.14 Salt Preparation and Fuel Pin Filling for MSR Program

Capsule Irradiation Experiment TeGen-2 1276.14.1 Salt Preparation 1296.14.2 Hydrofluorination 1306.14.3 U4+/U3+ Ratio Adjustment 1326.14.4 Preparation of Salt Fill Vessel 1326.14.5 Salt Transfer 132

6.15 Salt Preparation and Filling of TeGen-3 and -4 1356.16 Operation of TeGen-2 and -3 136

6.16.1 Operating History of TeGen-2 and -3 1396.16.2 Data Analysis for TeGen-2 and -3 1396.16.3 Preliminary Results of TeGen-2 1416.16.4 Future Irradiations 142

6.17 Examination of TeGen-2 143

7. FUEL PROCESSING MATERIALS DEVELOPMENT 1637.1 Summary of Compatibility Studies 163

7.1.1 Ta-10% W Thermal Convection Loop Test 1637.1.2 Dissimilar Material Tests 163


8. CHEMISTRY OF FLUORINATION AND FUEL RECONSTITUTION 170

9. ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 1729.1 Metal Transfer Process Development 172

9.1.1 Entrainment Studies in Experiment MTE-3B 1729.1.2 Removal of LiCl and Bi-Li Phases and Addition of Purified Solutions 1739.1.3 Experiments Nd-3 and Nd-4 1739.1.4 Results 174

9.2 Mass-Transfer Studies Using Water-Mercury Contactors 1779.2.1 Experimental Equipment and Procedure 1789.2.2 Experimental Results 179

9.3 Continuous Fluorinator Development 1849.3.1 Autoresistance Heating Test AHT-4 1859.3.2 Frozen-Salt Corrosion Protection Demonstration (FSCPD) 186

9.4 Fuel Reconstitution Engineering Development 1899.4.1 Hydrodynamic Operation 1919.4.2 Calibration of the UF6 Metering System 1929.4.3 Calibration of Ar-UF6 Gas Density Detector 1929.4.4 Calibration of the HF-H2 Gas Density Cell 193

PART 5. SALT PRODUCTION

10. PRODUCTION OF FLUORIDE SALT MIXTURES FOR RESEARCH AND DEVELOPMENT 197

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