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Effects of silver and strontium ions co-implanted into silicon carbide
Dissertation (MSc (Physics))--University of Pretoria, 2020.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2020
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| _version_ | 1867613443471704064 |
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| access_status_str | Open Access |
| author2 | Hlatshwayo, Thulani Thokozani |
| author_browse | Hlatshwayo, Thulani Thokozani |
| author_facet | Hlatshwayo, Thulani Thokozani |
| collection | Thesis |
| dc_rights_str_mv | © 2019 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 (Physics))--University of Pretoria, 2020. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/77386 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:36:13.892Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/77386 Effects of silver and strontium ions co-implanted into silicon carbide Hlatshwayo, Thulani Thokozani nqophisamtshonisi@gmail.com Mlambo, Mbuso Mtshonisi, Nqophisa Physics UCTD Dissertation (MSc (Physics))--University of Pretoria, 2020. In modern nuclear reactors safety is improved by cladding the fuel kernel with chemical vapor deposited layers of pyrolytic carbon and silicon carbide. Amid these cladding layers SiC is the primary diffusion barrier of radioactive fission products. During normal operations at about 900 ℃ to 1250 ℃, the coated fuel particle retains almost all the radioactive fission products excluding silver (Ag), strontium (Sr) and europium (Eu). Substantial research has been studied on the migration behavior of Ag in SiC while limited work has been done on the migration behavior of Sr and Eu in SiC. Moreover, less is known on the migration behavior of Ag in the presence of other important radioactive fission products in SiC. In this study, the effects of Ag and Sr co-implanted into polycrystalline SiC were studied. 360 keV of Ag and Sr ions were individually implanted into polycrystalline SiC, both to a fluence of 2×〖10〗^16 〖cm〗^(-2) at 600 ℃ (Ag-SiC and Sr-SiC). Some of the Ag-SiC samples were then implanted with 280 keV Sr ions to a fluence of 2×〖10〗^16 〖 cm〗^(-2) at 600 ℃ (Ag&Sr-SiC). This high temperature of implantation was chosen to maintain the crystallinity of the substrate and also the modern nuclear reactors are premeditated to function at elevated temperatures. The implanted samples were isochronally annealed at temperatures varying from 1000 ℃ to 1400 ℃ in steps of 100 ℃ for 5 hours. Structural and surface morphological evaluations were monitored by Raman spectroscopy and scanning electron microscopy (SEM) while the migration behavior of implanted species were monitored by Rutherford backscattered spectrometry (RBS). Both individual and co-implantations retained crystallinity of polycrystalline-SiC with some defects. More defects were observed in the co-implanted samples. Annealing the samples caused progressive annealing of defects and appearance of SiC crystallites on the surface. These crystallites grew with annealing temperature and their growth was enhanced in the samples implanted with Ag. Neither migration nor loss of Sr were observed in Sr-SiC samples throughout the annealing steps. While annealing the Ag-SiC and Ag&Sr-SiC samples affected implants to shift towards the surface accompanied by loss at temperatures above 1400 ℃. Hence the presence of Ag has role in the migration and the loss of the implanted species. Physics MSc (Physics) Unrestricted 2020-12-17T11:49:28Z 2020-12-17T11:49:28Z 2021 2020 Dissertation * A2021 http://hdl.handle.net/2263/77386 en © 2019 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 | Physics UCTD Effects of silver and strontium ions co-implanted into silicon carbide |
| title | Effects of silver and strontium ions co-implanted into silicon carbide |
| title_full | Effects of silver and strontium ions co-implanted into silicon carbide |
| title_fullStr | Effects of silver and strontium ions co-implanted into silicon carbide |
| title_full_unstemmed | Effects of silver and strontium ions co-implanted into silicon carbide |
| title_short | Effects of silver and strontium ions co-implanted into silicon carbide |
| title_sort | effects of silver and strontium ions co implanted into silicon carbide |
| topic | Physics UCTD |
| url | http://hdl.handle.net/2263/77386 |