1. UCLA - S.Sharafat: ITER TBM Dec. ’04 DCLL ITER-TBM: Design for Accident Relevant Loading Jaafar A. El-Awady, P. Rainsberry, S. Sharafat, and N. Ghoniem, University of California Los Angeles ITER-TBM Meeting UCLA March 2-5, 2005

2. UCLA - S.Sharafat: ITER TBM Dec. ’04 Outline  Model of Dual Coolant Lead Lithium (DCLL) Test Blanket Module.  “Back of the Envelope” FEM to determine design features, most relevant to accident loading.  Detailed FEM analysis Results.  Design Modifications based on FEM analysis.

3. UCLA - S.Sharafat: ITER TBM Dec. ’04 Dual Coolant PbLi Concept 1940 Module Height 38 Top Plate 38 Bottom Plate First Wall Mo Dagher,Mar.1st

4. UCLA - S.Sharafat: ITER TBM Dec. ’04 Accident Simulation  An accident scenario is simulated for a leakage of Helium into DCLL-TBM  Structural analysis was performed with the following conditions:  Leakage of 8 MPa Helium into DCLL-TBM, thus increasing the pressure in the breeder channels to 8 MPa  Extreme temperature conditions (T = 650 o C) is applied as a uniform temperature on the entire DCLL-TBM

5. UCLA - S.Sharafat: ITER TBM Dec. ’04 Model for Back-of-the Envelope” FEM 8 MPa Boundary Conditions Back wall constrained from moving in the horizontal Plane but free to expand in the vertical direction Extreme Temperatures applied T = 650 o C FEM 8 MPa Back Wall First Wall Horizontal plane Vertical direction

6. UCLA - S.Sharafat: ITER TBM Dec. ’04 “Back-of-the Envelope” Structure Analysis

7. UCLA - S.Sharafat: ITER TBM Dec. ’04 “Back-of-the Envelope” Structure Analysis 8 MPa Alternating Pattern of high stresses “shadowing” internal FW tube Structure: Maximum Stress = 524.19 MPa

8. UCLA - S.Sharafat: ITER TBM Dec. ’04 Back-of-the-Envelope FEM Summary  FE Models must include Detailed Design of the FW and Supporting Ribs to identify critical design features.  “Back of the Envelope” FEM shows the weakest “link” to be the edges between the FW and the internal support structure.  Internal support structure – FW bonds will take the DCLL module beyond allowable stresses of 300 MPa at elevated temperatures.

9. UCLA - S.Sharafat: ITER TBM Dec. ’04 Detailed FEM Analysis

10. UCLA - S.Sharafat: ITER TBM Dec. ’04 Detailed FE-Model A 3-D solid model of the TBM was created, including all of the FW channels. Over 200K elements. Symmetry boundary conditions where applied to simulate the entire TBM Meshed model showing internal support structures and FW-Channels

11. UCLA - S.Sharafat: ITER TBM Dec. ’04 Structure Analysis Results Displacements: Maximum Displacements occur at the tips and is equal to 8.435 mm Back View Iso Front View

12. UCLA - S.Sharafat: ITER TBM Dec. ’04 True Model Structure Analysis Results Stress Distribution:  = 530 MPa Critical section 1: (Rib-first wall) View A

13. UCLA - S.Sharafat: ITER TBM Dec. ’04 True Model Structure Analysis Results Critical section 2: (top plate – first wall connection) View B  = 616 MPa Looking from the inside up at the top PLATE Top Plate FW (from the inside) Rib (not all the way to top Plate

14. UCLA - S.Sharafat: ITER TBM Dec. ’04 Channeled FW to Equivalent “Solid” FW Stresses: Equivalent Model with effective thickness for same stress True Model While the transformed model gave an average stress distribution equivalent to the true model, it wasn’t capable of capturing the critical sections were the stresses have doubled (these sections will be described in the following slides).

15. UCLA - S.Sharafat: ITER TBM Dec. ’04 Reinforced Rib-FW Structure Adding more material between top Channel of FW and Top Plate (4 mm)

16. UCLA - S.Sharafat: ITER TBM Dec. ’04 Reinforced Rib-FW Contact Model: Structure Analysis Max:  ~415 MPa Max: ~8 mm Front view Back view

17. UCLA - S.Sharafat: ITER TBM Dec. ’04 Reinforced Rib-FW Structure Adding material (4x4 mm) Reduced Maximum Stresses from 530 MPa to 450 MPa  = 450 MPa First Wall Added material

18. UCLA - S.Sharafat: ITER TBM Dec. ’04 Reinforced Top Plate Side Wall Contact  = 415 MPa Adding material (4x15 mm) Reduced Maximum Stresses from 616 MPa to 415 MPa

19. UCLA - S.Sharafat: ITER TBM Dec. ’04 Summary  The entire DCLL TBM including FW channel detail was modelled for an over pressurization analysis (8 MPa).  Stress distribution on support structure/FW contact areas shows “shadowing” of FW channel detail on stress states.  Without reinforced support structure FW and Top/Bottom Plate contact areas, stresses are high.  Modifying internal Rib-FW/Top/Bottom-Plate contact areas can reduce maximum stresses significantly.  Details of the most optimized reinforcement design are yet to be determined.