1. Fusion Reactor Steel Sonny Martin Tevis Jacobs Yucheng ZhangJiawen Chen

2. Fusion Neural networks Models Predictions and conclusions

3. Fusion

4. Neutron damage: 100-150 dpa Transmutation helium Up to 700ºC Design parameters

5. Irradiation Effects Irradiation hardening Irradiation creep Activation Swelling

6. Irradiation Hardening Dislocation loops – Condensation of defects Helium bubbles

7. Why model? Suitable reactor does not exist Experiment would be costly Help design ITER Because we’re doing a modelling course!

8. It cost an estimated £8 million to produce the current data (¥116 million, $14 million, €11 million) from FISSION reactor.

9. Fusion Neural networks Models Predictions and conclusions

10. Neuron Biological Neuron Digital Neuron Activation Function (tanh) inputoutputinputoutput

11. Input Layer Hidden Layer Output Layer f f f X X Y

12. f i = tanh ( Σw ij (1) x j + θ i (1) ) y = Σw i (2) f i + θ (2)

13. ‘OR’ logic Value InputOutput X1X1 X2X2 Y 000 011 101 111

14. Train by adjusting weights Y = X 1  W 1 + X 2  W 2 +W 3 a d b c WiWi WiWi WiWi WiWi W 1 =1, W 2 =1, W 3 =0

17. y x

18. Fusion Neural networks Models Predictions and conclusions

19. Total Elongation

20. Adding known science He/dpa exp[-1/(Irradiation T)] exp[-1/(Test T)] 1/L

21.  y 2 =  y 2, dislocations +  y 2, bubbles N c = (5.36*10 12 ) exp N G = atoms of He P G = r eq =

25. Yield Strength

26. Fusion Neural networks Models Predictions and conclusions

27. Yield Strength Predictions

28. Uniform Elongation

29. Uniform Elongation Predictions

30. Measured Uniform Elongation Data

31. We were not able to create a reasonable model for uniform elongation

32. For the first time, predictions have been made of suitability of austenitic steel for fusion

33. Total Elongation Predictions

34. Measured Total Elongation Data

35. For austenitic stainless steels irradiated to doses consistent with fusion, ductility is likely to be unacceptably small

36. Yield Strength Predictions

37. Irradiation hardening makes the steel brittle

38. BCC steel might be better

39. Future work Verify experimentally (in 15 years) Investigate discrepancy in uniform ductility Record comprehensive data when doing experiment

40. Acknowledgements Professor Harry Bhadeshia Richard Kemp The noodle lady in Market Square