1. 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

2. INDIAN FUSION ROAD MAP Power Plant DEMO SST-2 ITER Participation SST-1
2050
Fusion Power Reactor
DEMO
2035
- Qualification of Technologies
- Qualification of reactor components & Process
SST-2
2020
Indigenous Fusion Experiment
ITER Participation
2005
scientific and technological feasibility of fusion energy
SST-1
2004
Steady State Physics and related technologies
TBM
Program
Prototype
Programs
1986
ADITYA Tokamak

3. DEMO Fusion Reactor Core
Breeding Blanket °C
Blanket
Vertical Manifold ~320°C
Vessel
Neutron
Shield ~320°C
Divertor
Vacuum Vessel ~100°C
Magnet
DEMO = Demonstration Fusion Reactor Plant
-FZK

4. BLANKET Functions Tritium Breeding High grade heat extraction
Radiation Shielding

5. TBM Program in ITER
The ITER Basic Device has Shielding Blanket, but no Breeding Blanket
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.”
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

6. THE ITER DEVICE Parameters ITER DEMO Frame TBM
Height: 25 m, Diameter: 28 m
Frame
TBM
1.66 m (h) x 0.48 m (w) x 0.54 m (t)
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

7. Indian TBM Concepts 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

8. 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 Inlet
He Purge Outlet
Radial 536
Poloidal 1660
U-shaped First wall
Box structure
Toroidal 480

9. LLCB TBM Parameters LLCB 1.66 m (h) x 0.484 m (w) x 0.54 m (t) 90 %
Li-6 enrichment
350/480 oC
Pb-Li inlet/outlet
0.3 MPa
He pressure drop in module
8 MPa
Helium pressure
350 / 480 oC
He inlet/outlet
Helium and Pb-Li
Primary coolant
Al2O3 or Other choice
MHD insulation
SS 316 LN IG
Neutron reflector / shield
Pb-17Li, Li2TiO3
Breeder
IN-RAFMS
Structural material
1.66 m (h) x m (w) x 0.54 m (t)
Helium as Purge gas for Tritium extraction

10. TBM Materials
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

11. 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 First Wall, End of life: dpa (5 yr)
Transmutation to Helium: 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.

12. Structural Steels for TBM
RAFM Steel : 9Cr W Ta V Si, C
Composition tailored to reduce activation and waste
Operational Temperature window: °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: °C

13. Reduced Activation Ferritic Martensitic Steels (RAFMS) Typical
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 B
< 0.001 Ti
< 0.005 Nb Mo Ni Cu Al Si
< 0.05 Co
As+Sn+Sb+Zr
< 0.03
Process : Vacuum Induction Melting (VIM)
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
Plates of dimensions: (in mm)
(i) L x 1500 W x T
(ii) 1700 L x 1500 W x T
Rectangular tubes: (18mm x 18 mm)
Powder &
Wire form (for welding )
Quantity Required:
Each TBM (Typically) : ~ 5 Ton
To develop 8 TBMs in 15 years : ~ Ton
IGCAR & MIDHANI jointly developing

14. RAFMS Development : Critical Issues
Characterization and understanding of degradation due to neutron irradiation ( ~ 550 C)
 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. ODS alloys ODS alloys Advantages Disadvantages Disadvantages with FMS
Long Term Needs
ODS alloys
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 °C by powder metallurgy Route (ODS)
ODS alloys
Advantages
Disadvantages
12-16% 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
 Cr , 1 % W and 0.3 %Y2O3 (50 nm size) without Titanium

16. 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

17. Component-1 : U-Shaped First Wall Box Structure
He Channel
(Top plate cooling)
He Channel
First Wall
HIPPING Or
Investment
Casting
Channel
20 x 20 mm
No. of Channel
64 Nos.
Corner Radius Inside Channel
2.5 mm
He Channel
Overall Dimension: 1.66 m (h) x 0.48 m (w) x 0.54 m (t)

18. Typical Dimensions (Reference EU Trials)
HIPPING
First Wall thickness : ~ 25 – 30 mm
Cooling channels : x mm2 (5 - 6 mm rib)
Top & Bottom covers : 30 – 32 mm
Stiffening plates / flow divider wall thickness : 5 – 8 mm
1000 oC, 130 MPa
Options
200
TBM FW
Built-in Cooling Channels
300 18

19. TBM FW mockup fabrication (EU - References)
200mm X 200mm X 100mm (height)
F82H as recieved
Grain Size # G：5
Grain Size：60mm
1040 ºC x 2hr x 150MPa
Grain Size #G：2
Grain Size：170mm 19

20. Japanese Trials with RAFMS (F82H)
300
200
Built-in Cooling Channels
Horizontal Channels 20

21. Component-2 Top Plate Assembly of LLCB TBM
Rib
BY HIPPING Or Investment Casting

22. Dimensions of Top Plate-3 with Rib (He Inlet/Outlet)
ISO View
Plate Thickness
4 mm
Rib Thickness
6 mm
Rib Width
Unspecified Corner Radius
2 mm
All Dimensions are in mm

23. Component-3 : Manifold Arrangement with Inner Back Plate
Breeder
First Wall
He Inlet for
Back Plate
He Channel
Inner Back Plate
He Outlet for
Back Plate

24. Dimension of Inner Back Plate
Detail View B
Channel Dimension
20 x 20
Total No. of Channel 32
Unspecified Corner Radius = 10 mm
All Dimension Are in mm
Section View
A:A

25. Arrangement with Outer Back Plate
Manifold
Arrangement with Outer Back Plate
Outer Back Plate
First Wall
Inner Back Plate
He Outlet for Back Plate
He Channel
Outer Back Plate
He Inlet for Back Plate

26. Dimension of Outer Back Plate

27. HIPPING Joint Properties
EU Ref.

28. 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 Sound structural welds: Free of cracks, low pores
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)

30. 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 (Reference EU R&D) YAG LASER Coolant Panels
- Laser power: 4 kW
- Travel speed: 0.35 m/min
- Focal length: 150 mm
- Twin spot with d = 2.1 mm
Plate – Plate welding
5 - 8 mm to 12 – 15 mm
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.
Coolant Panels

32. LASER Welding on TBM Mock-up Trials
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
Assembly mode I & II Clamping Conditions
(Reference EU R&D)
Dissimilar Joints (RAFMS/SS 316 LN)
SP- Fusion Butt welding (YAG LASER) > 2 KW
Pipes Dia: 75 – 85 mm, thick = mm
- Metallographic
- Destructive / non-destructive tests

33. Major Milestones (1/2) Sr. No. 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 5
TBM Preliminary Safety Report (for each concept and dummy plug) 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

34. Major Milestones (2/2) 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 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

35. Summary
Materials 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

36. Thank you

40. Damage rate [dpa/year]
Irradiation Modes
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

41. Electron Beam Welded 25 mm Plate
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

42. 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

43. Effect of Post-Weld Heat Treatment on Hardness of Eurofer 97 EB Welds
J.W. Rensman, E. Rigal, R. Meyder, A. Li Puma / ICFRM-12 (2005)
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.