An In-situ TEM Investigation of Silicon Carbide under Irradiation Chris Pawley University of Salford UNTF 2011, April 2011, University of Huddersfield University of Salford Materials & Physics Research Centre M-F. Beaufort & J-F. Barbot University of Poitiers E. Oliviero CSNSM, Orsay, Paris S.E. Donnelly & J.A.Hinks University of Huddersfield

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

University of Salford Materials & Physics Research Centre 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 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 G 2 20.

University of Salford Materials & Physics Research Centre Results MIAMI facility –3.5keV He + ions –2.7x10 13 ions.cm -2.s -1 –End point: 2.0x10 17 ions.cm -2 Aim: Observe nucleation & growth

University of Salford Materials & Physics Research Centre Results JANNuS facility –2MeV Au ++ ions –3x10 11 ions.cm -2.s -1 –End point: 2.5x10 15 ions.cm -2 Aim: Observe behaviour under displacing irradiation

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

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