An In-situ TEM Investigation of Silicon Carbide under Irradiation

Chris PawleyUniversity of Salford

UNTF 2011, 11-13 April 2011, University of Huddersfield

University of SalfordMaterials & Physics Research Centre

http://www.cse.salford.ac.uk/sumc/

M-F. Beaufort & J-F. BarbotUniversity of Poitiers

E. OlivieroCSNSM, Orsay, Paris

S.E. Donnelly & J.A.HinksUniversity of Huddersfield

University of SalfordMaterials & 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 SalfordMaterials & 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 SalfordMaterials & Physics Research Centre

Example applications of SiCCurrent• 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 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

TRISO coated particle 1

Tokomak design employed at ITER 2

University of SalfordMaterials & 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 SalfordMaterials & 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 G2 20.

University of SalfordMaterials & 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

University of SalfordMaterials & 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

University of SalfordMaterials & Physics Research Centre

Interpretation of resultsBubble observations• Growth is inhibited during 2nd

irradiation step– Thermal and irradiation processes

competing

• SRIM supports this

University of SalfordMaterials & Physics Research Centre

Interpretation of resultsSurface 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 SalfordMaterials & 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 SalfordMaterials & Physics Research Centre

Acknowledgements• EPSRC

– Financing the development of the MIAMI facilityunder 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