Test Blanket Module: Steels & Fabrication Technologies

E. Rajendra Kumar and TBM Team

Institute for Plasma Research

Bhat, Gandhinagar

WS&FT-08, 21st July 2008, IPR

INDIAN FUSION ROAD MAP

Indigenous Fusion Experiment

- Qualification of Technologies- Qualification of reactor

components & Process

scientific and technological feasibility of fusion energy

SST-2

DEMO

ITER Participation

Steady State Physics and related technologies

SST-1

ADITYA Tokamak

1986

2004

2005

2035

2020

Fusion Power Reactor

Power Plant 2050

TBM Program

Prototype Programs

3

Breeding Blanket

400-550°C

Breeding Blanket

400-550°C

VacuumVessel ~100°C

VacuumVessel ~100°C

DEMO = Demonstration Fusion Reactor DEMO = Demonstration Fusion Reactor Plant

DEMO Fusion Reactor Core

Blanket

Divertor

VerticalManifold ~320°C

VerticalManifold ~320°C

NeutronShield ~320°C

NeutronShield ~320°C

-FZK

Magnet

Vessel

4

High grade heat extraction

Radiation Shielding

BLANKETFunctions

Tritium Breeding

5

The ITER Basic Device has Shielding Blanket, but no Breeding Blanket

Breeding Blankets will be tested in ITER, by inserting Test Blanket Modules (TBM) in specially dedicated ports

All the ITER Parties have their own TBM program and developing indigenous Materials & Technologies.

CHINA, EUROPE, INDIA, JAPAN, KOREA, RUSSIA & US

TBM Program in ITER

ITER mission : “ITER should test tritium breeding module concepts that would lead in a future reactor to tritium self-sufficiency, the extraction of high grade heat and electricity production.”

6

Parameters ITER DEMO

Surface Heat Flux (MW/m2)

0.27 0.5

Neutron wall Loading (MW/m2)

0.57 2.5

Pulse length (sec)

Up to 3000 ~ continuous

Duty cycle 0.25 -

Avg. Neutron Fluence (MWa/m2)

0.1

(for initial 10 years)

7.5

Frame

TBM

1.66 m (h) x 0.48 m (w) x 0.54 m (t)

7

Lead-Lithium cooled Ceramic Breeder (LLCB) Tritium Breeder: Lithium-Titanate pebbles Breeder Coolant: Lead-Lithium eutectic alloy (multiplier and breeder) Structural Material : Reduce Activation FMS

Solid Type: Helium Cooled Ceramic Breeder (HCCB) Tritium Breeder: Lithium-Titanate / Lithium Silicate pebbles Multiplier : Beryllium Pebbles Structural Material : Reduce Activation FMS Coolant : helium gas

Indian TBM Concepts

Lead-Lithium cooled Ceramic Breeder (LLCB) TBM

Bottom Plate

Outer Back Plate

Support

Shear Keys

He Outlet

Pb-Li Inlet

Top Plate

He Inlet

Pb-Li Outlet

He Purge InletHe Purge Outlet

Radial 536

Poloidal 1660

U-shaped First wallBox structure

Toroidal 480

9

LLCB TBM Parameters

1.66 m (h) x 0.484 m (w) x 0.54 m (t)

LLCB

Pb-Li Inlet pipe

Pb-Li Outlet pipe

He Inlet/Outlet concentric pipe

Bottom Plate

Top Plate

Outer Back Plate

Inner Back Plate

Pb-Li Inlet Manifold

First Wall

Ceramic Breeder zones

Helium as Purge gas for Tritium extraction

10

Structural material : Reduced Activation Ferritic Martensitic Steel (RAFMS) and ODS

Tritium Breeder :

Solid : Li4SiO4, Li2TiO3 Liquid : Pb-17Li Enriched Lithium : Li-6 (30 – 90 %)

Neutron multiplier : Be, Be12Ti, Pb

Composite Material : SiCf/SiC (FCI)

Coatings : Be, Alumina, Erbium oxide coatings

Neutron Shielding and External Piping : SS 316 LN-IG

TBM Materials

Key Material Issues in Fusion Devices

The 14 MeV neutrons produce transmutation nuclear reactions and atomic displacement cascades inside the materials

Damage and transmutation imply degradation of physical and mechanical properties of materials ( Swelling, Hardening, LD, LCS, LFT..)

DEMO: Radiation damage @ First Wall, End of life: 100 - 150 dpa (5 yr) Transmutation to Helium: 1200 -1800 appm He

The existing sources of 14 MeV neutrons have a small intensity and do not allow us to get important damage accumulation in a reasonable time.

It is necessary to simulate irradiation by 14 MeV neutrons (@ 550 C), by using either fission neutrons, or high energy protons.

Presently, Materials are irradiated with fission neutrons and with high-energy protons. Results are interpolated for fusion irradiation conditions.

Structural Steels for TBM

RAFM Steel : 9Cr W Ta V Si, C Composition tailored to reduce activation and waste

Operational Temperature window: 300-550°C

To be used as structural material for the TBM and in DEMO blankets

Oxide dispersion strengthened (ODS) Steels

(Potential Candidate to replace RAFMS)

Operational Temperature window: 350-650°C

13

Elements Wt. %

Cr 8.80 – 9.20

C 0.10 – 0.12

Mn 0.4 0 – 0.60

V 0.18 – 0.24

W 1.0 – 1.20

Ta 0.07 – 0.10

N 0.02 – 0.04

O < 0.01

P < 0.002

S < 0.002

B < 0.001

Ti < 0.005

Nb < 0.001

Mo < 0.002

Ni < 0.005

Cu < 0.002

Al < 0.005

Si < 0.05

Co < 0.005

As+Sn+Sb+Zr < 0.03

Reduced Activation Ferritic Martensitic Steels (RAFMS)

Typical RT 300 oC 500 oC

UTS (Mpa) 640 – 680 520 – 560 400 – 440

YS (E 0.2%)(Mpa) 540 – 580 465 – 485 385 – 40

DBTT : < -70 oC

Process : Vacuum Induction Melting (VIM)

Quantity Required: Each TBM (Typically) : ~ 5 Ton To develop 8 TBMs in 15 years : ~ 40 - 50 Ton

Plates of dimensions: (in mm)(i) 1700 L x 1500 W x 12-15 T (ii) 1700 L x 1500 W x 25-30 T Rectangular tubes: (18mm x 18 mm)Powder &Wire form (for welding )

IGCAR & MIDHANI jointly developing

14

RAFMS Development : Critical Issues

Characterization and understanding of degradation due to neutron irradiation ( ~ 550 C)

3 -15 dpa (engineering database for TBM design, fabrication and TBM licensing)

Major Issues:– Development of Reliable joints manufacturing process (HIP, EBW, LW etc..)

– Compatibility with Breeder Materials (Li-ceramics, flowing Pb-Li in magnetic filed)

– Anti-Corrosion / Anti-Permeation Barriers development

– Creep-Fatigue Interaction due to high temperature cyclic operation (data validation)

– High Temperature Design Criteria as per the ITER SDC (RCCMR & ASME)

LONG TERM R&D for the Development of fully qualified LAFMS material Modeling & Simulation Chemical Composition Characterization Mock-up fabrication Optimization of joining techniques Neutron irradiation Industrial Production

15

Disadvantages with FMS DBTT decrease after irradiation at Tirr < 400°C; The welds need heat treatments Upper operating temperature limited by creep strength: Tmax 550°C Possible solution: Tmax in range 550-650 °C by powder metallurgy Route (ODS)

ODS alloys Advantages Disadvantages12-16% Cr ODS ferritic steel

Higher temperature capability

Better oxidation resistance

Anisotropic mechanical properties

Lower fracture toughness

9% Cr ODS ferritic/martensitic steel

Nearly isotropic properties after heat treatment

Better fracture toughness

Scalable fabrication

Limited to temperature below ~700 C

Marginal oxidation resistance at high temperatures

8-9.5 Cr , 1 % W and 0.3 %Y2O3 (50 nm size) without Titanium

ODS alloysLong Term Needs

Manufacturing Technologies adopted for TBM

HIPPING / INVESTMENT CASTING

EB Welding

Hybrid (MIG/LASER)

TIG Welding

LASER Welding

Testing Methods

Ultrasonic testing

X-ray / γ-ray testing

Dye Penetrant testing

Helium leak tightness

Component-1 : U-Shaped First Wall Box Structure

First Wall

He Channel

He Channel

He Channel (Top plate cooling)

HIPPING

Or

Investment

Casting

Overall Dimension: 1.66 m (h) x 0.48 m (w) x 0.54 m (t)

Channel 20 x 20 mm

No. of Channel

64 Nos.

Corner Radius Inside Channel

2.5 mm

18

Typical Dimensions (Reference EU Trials) HIPPING First Wall thickness : ~ 25 – 30 mm

Cooling channels : 15-18 x 15-18 mm2 (5 - 6 mm rib)

Top & Bottom covers : 30 – 32 mm

Stiffening plates / flow divider wall thickness : 5 – 8 mm

300

200

Built-in Cooling Channels

Options

1000 oC, 130 MPa

TBM FW

19

TBM FW mockup fabrication (EU - References)

F82H as recievedGrain Size # G ： 5Grain Size ： 60m

1040 ºC x 2hr x 150MPa Grain Size #G ： 2Grain Size ： 170m

200mm X 200mm X 100mm (height)

20

300

200

Built-in Cooling Channels

Japanese Trials with RAFMS (F82H)

Horizontal Channels

Component-2 Top Plate Assembly of LLCB TBM

Top Plate 1

Top Plate 3

Top Plate 2

Rib

BY HIPPING Or Investment Casting

All Dimensions are in mm

Plate Thickness 4 mm

Rib Thickness 6 mm

Rib Width 4 mm

Unspecified Corner Radius 2 mm

ISO View

Dimensions of Top Plate-3 with Rib (He Inlet/Outlet)

Component-3 : Manifold Arrangement with Inner Back Plate

Inner Back Plate

First Wall

Breeder

He Inlet for

Back Plate

He Outlet for

Back Plate

He Channel

Inner Back Plate

Dimension of Inner Back Plate

Section View A:A

Detail View B

Channel Dimension

20 x 20

Total No. of Channel

32

Unspecified Corner Radius = 10 mm

All Dimension Are in mm

Outer Back PlateFirst Wall

Outer Back Plate

Inner Back Plate

He Outlet for Back Plate

He Inlet for Back Plate

He Channel

Manifold Arrangement with Outer Back Plate

Dimension of Outer Back Plate

27

HIPPING Joint Properties

EU Ref.

Investment casting

Investment casting is a potentially attractive alternative to HIP for first-wall, grid plate and manifold fabrication

– Reduces the need for extensive joining which should improve reliability (joints are typically the origin of structural failures)

– Reduces the amount of NDE needed (few joints).

– Potentially less expensive than other fabrication methods.

– Complex castings of 9-10 Cr steels have been produced with mechanical properties similar to those of wrought products

(Ref: Valves & Steam Turbine applications)

29

EB-Welding

For High Depth Welding:

High voltage: 150 kV,

Welding current: 72 mA,

Travel speed: 0.3 m/min

40 mm and weld width 2 mm.

Macrography of Eurofer / 316LN

EBW (1.5 mm thick)

Sound structural welds: Free of cracks, low pores

Major Tasks in EBW development

Development of welding procedure for thick RAFMS plates

Optimization of Welding process (current density, speed, environ.)

Characterization of weld joints (ITER-SDC RCC-MR and ASME codes)– Radiography Test– Effect of Post-Weld Heat Treatment on Hardness (needs

optimization)– Effect of neutron Irradiation on weld joints (Microstructures,

Mechanical Properties (TS, DBTT, YS, FT)

Optimization of EBW process in actual TBM mock-ups (In real joint configurations)

31

LASER Welding

Plate – Plate welding

5 - 8 mm to 12 – 15 mm

YAG LASER

Penetration of the melt run ranges typically from 4 to 8 mm (WS = 130 cm/min).Metallurgical analysis: hot cracks (max. 1.2 mm) and gas pores (max. 0.7 mm).RAFMS / EUROFER is sensitive to hot cracking.

- Laser power: 4 kW

- Travel speed: 0.35 m/min

- Focal length: 150 mm

- Twin spot with d = 2.1 mm

Coolant Panels

(Reference EU R&D)

SP- Fusion Butt welding (YAG LASER) > 2 KW

Pipes Dia: 75 – 85 mm, thick = 3 - 6 mm

- Metallographic

- Destructive / non-destructive tests

Join realized in 2 passes (Top & Bottom)

Mode I: Successive and opposite direction of the passes;

Mode II : Simultaneous and same direction of the passes

LASER Welding on TBM Mock-up Trials

Dissimilar Joints (RAFMS/SS 316 LN)

Assembly mode I & II Clamping Conditions(Reference EU R&D)

33

Sr. No.

Major Milestones (1/2) Completion by:

1 Materials composition definition 12/2008

2 TBM Quality management system establishment (e.g., QA) 06/2009

3 Out-Of-Pile characterization of DEMO-relevant structural material and TBM fabrication process validation (at laboratory level)

12/2009

4 TBM system conceptual design 12/2009

5 TBM Preliminary Safety Report (for each concept and dummy plug)

12/2009

6 Small/medium size TBM mock-ups fabrication addressing critical components (industrial manufacture or, at least, industrially compatible manufacture)

12/2010

7 Small/medium size TBM mock-ups testing results 12/2011

8 Completion of data base for structural material and joints for use in design codes and codes & standards

6/2012

9 Detailed design of the first TBM system to be installed in ITER day one (1st Plasma)

06/2012

10 Completion of data base for structural material and joints under irradiation (at least, 3 dpa)

06/2014

11 End of fabrication of large size TBM mock-up and associated system

06/2014

12 End of testing and qualification of large size TBM mock-up and associated system in appropriate facilities

12/2015

13 Delivery of TBM systems to ITER 12/2016

14 End of 1st TBM System acceptance tests (e.g., leakage tests, pressure tests, compatibility check with ITER interfaces) and Commissioning

12/2017

15 TBM Safety Report to be provided with QA records during construction and reception tests

12/2017

Major Milestones (2/2)

SummaryMaterials Requirement and related Manufacturing technologies for TBM development has been projected

The fabrication technologies development for TBM need to be initiated through mock-ups and prototype fabrication and testing

The qualification according to codes and standards needs to be

finalized and harmonized as per the ITER requirements

The budget for the TBM Program is available.

We invite R&D centers to initiate the developmental activities for a committed delivery to meet the ITER time schedule

35

Thank you

36

37

38

39

• Fusion neutrons, fission neutrons, high energy protons:

• Strong differences in the production rates of impurities

Defect poduction

(in steels)

Fusion neutrons

(3-4 GW reactor,

first wall)

Fission neutrons

(BOR 60 reactor)

High energy protons

(590 MeV)

Damage rate [dpa/year]

20-30 ~ 20 ~ 10

Helium [appm/dpa]

10-15 ≤ 1 ~ 130

Hydrogen [appm/dpa]

40-50 ≤ 10 ~ 800

Irradiation Modes

Effect of 300°C Irradiation on Eurofer97 Base and EB Weld Metal Tensile Ductility

J.W. Rensman / NRG Irradiation Testing: Report on 300°C and 60°C Irradiated RAFM Steels (2005)

25 mm Plate Electron Beam Welded 25 mm Plate

Effect of 300°C Irradiation on Eurofer97 Base and EB Weld Metal Impact Properties

J.W. Rensman / NRG Irradiation Testing: Report on 300°C and 60°C Irradiated RAFM Steels (2005)

25 mm Plate Electron Beam Welded 25 mm Plate

Effect of Post-Weld Heat Treatment on Hardness of Eurofer 97 EB Welds

• Research needs:– No systematic study of all

variables in the literature. There is a need to understand the controlling variables to optimize weld and PWHT for irradiation response.

– Irradiation testing of very fine grained HAZ.

– Irradiation testing of base and weld metal with multiple PWHTs.

J.W. Rensman, E. Rigal, R. Meyder, A. Li Puma / ICFRM-12 (2005)