22-30 July 2021
North-West University
Africa/Johannesburg timezone
More Information Coming Soon

Impact of helium (He) in the migration of strontium implanted 6H-SiC

26 Jul 2021, 12:15
15m
Potchefstroom Campus (North-West University)

Potchefstroom Campus

North-West University

Oral Presentation Track A - Physics of Condensed Matter and Materials Physics of Condensed Matter and Materials

Speaker

Thapelo Freddy Mokgadi (University of Pretoria)

Description

Impact of Helium (He) in the migration of strontium implanted 6H-SiC

T.F. Mokgadi$^1$, T.T. Hlatshwayo$^1$, M. Msimanga$^2$, V.A. Skuratov$^3$

‎$^1$ Physics Department, University of Pretoria, Pretoria, South Africa.‎
$^‎2$ Physics Department, Tshwane University of Technology, P Bag X680, Pretoria 0001, South Africa ‎
‎$^3$ Joint Institute for Nuclear Research, Dubna, Russia

‎Silicon carbide (SiC) is regarded as the main candidate material for nuclear energy ‎application, such as a structural material in future fusion reactors and as fuel cladding in ‎future generation fission reactors, based on its low neutron capture cross-section, outstanding ‎chemical and thermal stability. In fission reactors such as the PBMR, the fuel particle (TRISO ‎particle) where SiC is the main diffusion barrier of fission products (FPs), is able to retain ‎most of the radiologically important FPs with the exception of strontium ($^{90}$Sr), Europium (Eu) ‎and silver (Ag). $^{90}$Sr is an isotope of naturally occurring nontoxic and nonradioactive ‎strontium, it is also a by-product of fission reactions in nuclear reactors with yields of about ‎‎5.7% and 6.6% from U-235 and U-233, respectively. It has a half-life of about 29 years and ‎undergoes a beta decay into yttrium-90 ($^{90}$Y) accompanied by a decay energy of about 0.55 ‎MeV. This, is the more reason why it is important to investigate the retention of Sr in the ‎TRISO particle, specifically SiC. Simultaneous to the release of FPs in fission reactions is the ‎release of alpha-particles. Alpha-particles/helium ions (He$^+$) are a product of nuclear ‎reactions with generation rates of about 2.5 appm He/dpa and have been reported to form ‎bubbles in SiC which in the long run compromises its structural integrity. Therefore, in the ‎nuclear reactor environment SiC will be exposed to high dose, temperature irradiation, and ‎He$^+$ generation. ‎We will be presenting the results of a study that looks into the dual implantation of Sr and He at room temperature and the impact of He bubbles in the Sr migration in SiC at high temperatures.

Apply to be considered for a student ; award (Yes / No)?

Yes

Level for award;(Hons, MSc, PhD, N/A)?

PhD

Primary author

Thapelo Freddy Mokgadi (University of Pretoria)

Co-authors

Prof. Mandla Msimanga (Tshwane University of Technology) Dr V.A Skuratov (Joint Institute for Nuclear Research) Prof. Thulani Hlatshwayo (University of Pretoria)

Presentation Materials

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