NRC Pre-application Meeting 7-16-2020 (Proprietary Session)

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Enclosure 2

4A: Genesis Reactor Core

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Table of Contents4A. REACTOR DESCRIPTION 6

4a.1 Summary Description 6

4a.2 Reactor Core 8

4a.2.1 Reactor Fuel 13

4a.2.2 Control and Safety Rods 18

4a.2.3 Neutron Moderator and Reflector 22

4a.2.4 Neutron Startup Source 24

4a.2.5 Core Support Structure 24

4a.3 Reactor Tank and Pool 27

4a.4 Biological Shield 29

4a.5 Nuclear Design 30

4a.5.1 Normal Operating Conditions 30

4a.5.2 Reactor Core Physics Parameters 35

4a.5.3 Operating Limits 57

4a.6 Thermal-Hydraulic Design 59

4a.6.1 Thermal-Hydraulic Design Basis 59

4a.6.2 Thermal-Hydraulic Design Description 59

4a.6.3 Analytical Tools and Methods 60

4a.6.4 Target Element Thermal Analysis 60

4a.6.5 Reflector Element Thermal Analysis 63

4a.6.6 Control Rod Thermal Analysis 66

4a.6.7 Target Element Flow Channel Analysis 71

4a.6.8 Reflector/Control Rod Flow Channel Analysis 80

4a.7 Burnup Considerations 82

4a.7.1 Target Element Burnup 82

4a.7.2 Reflector Matrix Burnup 83

4a.7.3 Control Rod Burnup 83

4a.8 Summary and Conclusions 85

4a.9 References 86

Key Technical Considerations

• Driver Targets vs. Nominal Targets (as discussed in Eden Pre-application meeting 12-19-2019)• Targets are nearly identical, but with different design intent

• Molybdenum in driver target used for structural support• Steady-state irradiation for up to 30 kW for 21 days (nominal) and 60 days (driver),

but with low burnup

• Designs and Analyses key topics: • Safety Analysis: Analysis in chapter support assumptions in accident analysis• Cooling:

• target design and natural convection in pool must keep targets cool during operation. Target quality, annular design, and cladding gaps are emphasized through parametric analysis of failure modes

• Balancing Reactivity and burnup: • Reactivity and burnup must be balanced with unique Mo-99 production cycles

Key Themes• Designs are based heavily on Annular

Core Research Reactor at Sandia

• Eden reactor engineers have decades of experience in designing, building, and operating research type reactors at Sandia

• 1990s DOE Medical Isotopes Production Program included 37 targets at the center of the ACRR for Mo-99 production

• Tours of SNL facilities can be arranged to support NRC staff understanding of Eden facility designs, engineering experience, and operational intent.

Target Details

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Target Primary Design Requirements

• Target foil must maintain adequate heat transfer and sufficiently low temperatures to protect from clad or fuel melt.• Target foil must be in intimate contact with cladding; gaps greatly diminish

heat transfer

• Target cladding must not exceed critical heat flux limits

• Takeaway: Nuclear Design, Dimensions, Thermal Hydraulic Design of Reactor support the requirements above.• A wide variety of parametric analyses are presented in 4A and CALC reports to

demonstrate fulfillment of these design requirements.

Target Design Basis

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Target Design Basis (continued)

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Target Design Basis (continued)

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Target Design Basis (continued)

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Target Design Basis (continued)

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Target Design Basis (continued)

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Target Testing, Inspections, and Operations Requirements

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Summary of Reactor DesignProprietary InformationProprietary Information

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Reactor Pool and Transfer Canal Design

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Reactor Core Cut-Away

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Reactor Core Pitch

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Reactor Core Cut-Away (cont.)

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Beryllium Details

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Reactivity Considerations

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Control Rod Details

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Safety Rod Details

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Key Takeaways

• Eden is still progressing towards license submission with a one-step license process under Part 50 for the reactor + hot cell facility (including target fab facility)

• Estimated Submission Date: Oct. 1

• Eden is completing its application to FSAR standards and detail with an example shown of its approach with Chapter 4A.