An In-situ TEM Investigation of Silicon Carbide under Irradiation

1. University of Salford Materials & Physics Research Centre An In-situ TEM Investigation of Silicon Carbide under Irradiation Chris Pawley University of Salford M-F. Beaufort & J-F. Barbot University of Poitiers E. Oliviero CSNSM, Orsay, Paris S.E. Donnelly & J.A.Hinks University of Huddersfield http://www.cse.salford.ac.uk/sumc/ UNTF 2011, 11-13 April 2011, University of Huddersfield

2. Outline Where SiC fits into the nuclear industry Aim of our research Facilities utilised during the research Results obtained Understanding the results and feedback into a nuclear context University of Salford Materials & Physics Research Centre

3. Putting SiC into a nuclear context Why is it good as a nuclear material? Radiation Hardness Chemically inert High temperature stability Expected conditions Operating temperature between 550°c and 1000°c 10,000 appm 150 DPA University of Salford Materials & Physics Research Centre

4. Example applications of SiC Current TRISO coatings Future First wall material for fusion reactors University of Salford Materials & Physics Research Centre TRISO coated particle 1 [1] E.Lopez-Honorato et al, (2009) TRISO coated fuel particles with enhanced SiC properties, Journal of Nuclear Materials, Vol 392 Issue 2, Page 219-224 [2]A.Serpo,(2008) Nuclear fusion becomes economic reality? accessed 10/04/2011 http://www.zdnet.com.au/nuclear-fusion-becomes-economic-reality-339285739.htm Tokomak design employed at ITER 2

5. Aim of the Project Understand nucleation and growth processes of He bubbles in SiC Learn about the behaviour of SiC (and the He bubbles within) under high energy, heavy ion irradiation Feed into nuclear design considerations for the future University of Salford Materials & Physics Research Centre

6. In-Situ Radiation Facilities MIAMI facility at Salford Upto 100keV ions into JEOL 2000fx TEM JANNuS facility at Orsay, Paris Upto 2MV ions into FEI Technai G2 20. University of Salford Materials & Physics Research Centre

7. University of Salford Materials & Physics Research Centre Results • MIAMI facility • 3.5keV He+ ions • 2.7x1013 ions.cm-2.s-1 • End point: 2.0x1017 ions.cm-2 • Aim: Observe nucleation & growth

8. University of Salford Materials & Physics Research Centre Results • JANNuS facility • 2MeV Au++ ions • 3x1011 ions.cm-2.s-1 • End point: 2.5x1015 ions.cm-2 • Aim: Observe behaviour under displacing irradiation

9. Interpretation of results Bubble observations Growth is inhibited during 2nd irradiation step Thermal and irradiation processes competing SRIM supports this University of Salford Materials & Physics Research Centre

10. Interpretation of results Surface observations Reconfiguration due to sputtering Sputtering yield from SRIM supports this as a possibility Reduction in hermetic efficiency of SiC Could change the context in which silicon carbide is utilised in future nuclear applications Essential to interpret this for the neutron case University of Salford Materials & Physics Research Centre

11. Conclusions Bubble growth in SiC is inhibited by displacing irradiation. Changes to the depth profile of helium within SiC Significant surface change occurs towards the high end of the temperature range together with irradiation. Changes the hermetic efficiency of SiC in nuclear type applications University of Salford Materials & Physics Research Centre

12. Acknowledgements EPSRC Financing the development of the MIAMI facility under grant number EP/E017266/1 Royal Society Financing travel to JANNuS under an internationaljoint project with University of Poitiers University of Salford For the provision of a graduate teaching assistantposition which supports this research University of Huddersfield For hosting UNTF 2011 and for providing a new home to the MIAMI facility University of Salford Materials & Physics Research Centre