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access_status_str Open Access
author2 De Villiers, Johan Pieter
author_browse De Villiers, Johan Pieter
author_facet De Villiers, Johan Pieter
collection Thesis
dc_rights_str_mv © 2015 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc)--University of Pretoria, 2015.
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license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2015
publishDateRange 2015
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publisher University of Pretoria
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spelling oai:repository.up.ac.za:2263/50667 Silicon carbide integrity in TRISO fuel particles De Villiers, Johan Pieter mhakamuni.makamu@eskom.co.za Van Rooyen, Gerrit T. Makamu, Mhakamuni W. UCTD Chemical vapor deposition Silicon carbide Fracture toughness Vickers indentation test Internal pressure Fuel particles PBMR CVD SiC TRISO Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-07 SDG-07: Affordable and clean energy Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action Dissertation (MSc)--University of Pretoria, 2015. Chemical vapor deposited (CVD) silicon carbide (SiC) is used as a pressure vessel material for tristructural isotropic (TRISO) coated fuel particles for the high temperature pebble-bed reactor. Experience has shown that sometimes these particles fail in operation. The fracture toughness (KIC) was measured at room temperature to determine the maximum internal pressure that the CVD SiC layer in TRISO-coated fuel particles can withstand without fracturing. The KIC was measured using the indentation fracture toughness method on the curved-surface and cross-section of the test piece. The most suitable test load for measuring the KIC and Vickers hardness (HV) values of the CVD SiC layer was 100 g. The Evans-Davis model for calculating the KIC of ceramic materials was found to be the most appropriate for the CVD SiC layer. The average curved-surface KIC value was 3.47 MPa.√m, for the 51 mm test sample, which was tougher than the average cross-section KIC value of 3.17 MPa.√m. The wall thickness values of the samples tested were 28, 36, 39 and 51 mm and their corresponding measured mean curved-surface KIC values were 3.13, 3.07, 3.15 and 3.47 MPa.√m, respectively, which were on par with values reported in literature. The corresponding minimum curved-surface KIC values were 1.43, 1.67, 1.65 and 2.52 MPa.√m, respectively. These values were obtained from the average curved-surface KIC values minus five sigma (KIC = μ-5σ). The internal pressure that the SiC shell can handle without failing will depend on the initial crack length and the value of KIC. The pressure that a particle can withstand assuming the leak-before-break (i.e. a particle with a crack that extends right through the shell) was also used. This represents a more conservative value for the maximum pressure allowable without fracture when the fracture toughness is known. In fact, there is a considerable wide distribution in the measured fracture toughness. Using the average fracture toughness (μ) minus five times the standard deviation (σ) represents a conservative approach. The calculated maximum allowable pressure represents an even more conservative approach when both the LBB condition and the μ-5σ requirement are assumed. This is probably representative for the operation of the PBMR. tm2015 mi2025 Materials Science and Metallurgical Engineering MSc Unrestricted SDG-04: Quality education SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production SDG-13: Climate action 2015-11-25T09:47:09Z 2015-11-25T09:47:09Z 2015/09/01 2015 Dissertation Makamu, MW 2015, Silicon carbide integrity in TRISO fuel particles, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/50667> S2015 http://hdl.handle.net/2263/50667 en © 2015 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle UCTD
Chemical vapor deposition
Silicon carbide
Fracture toughness
Vickers indentation test
Internal pressure
Fuel particles
PBMR
CVD
SiC
TRISO
Engineering, built environment and information technology theses SDG-04
SDG-04: Quality education
Engineering, built environment and information technology theses SDG-07
SDG-07: Affordable and clean energy
Engineering, built environment and information technology theses SDG-09
SDG-09: Industry, innovation and infrastructure
Engineering, built environment and information technology theses SDG-12
SDG-12: Responsible consumption and production
Engineering, built environment and information technology theses SDG-13
SDG-13: Climate action
Silicon carbide integrity in TRISO fuel particles
title Silicon carbide integrity in TRISO fuel particles
title_full Silicon carbide integrity in TRISO fuel particles
title_fullStr Silicon carbide integrity in TRISO fuel particles
title_full_unstemmed Silicon carbide integrity in TRISO fuel particles
title_short Silicon carbide integrity in TRISO fuel particles
title_sort silicon carbide integrity in triso fuel particles
topic UCTD
Chemical vapor deposition
Silicon carbide
Fracture toughness
Vickers indentation test
Internal pressure
Fuel particles
PBMR
CVD
SiC
TRISO
Engineering, built environment and information technology theses SDG-04
SDG-04: Quality education
Engineering, built environment and information technology theses SDG-07
SDG-07: Affordable and clean energy
Engineering, built environment and information technology theses SDG-09
SDG-09: Industry, innovation and infrastructure
Engineering, built environment and information technology theses SDG-12
SDG-12: Responsible consumption and production
Engineering, built environment and information technology theses SDG-13
SDG-13: Climate action
url http://hdl.handle.net/2263/50667