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Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1

Assessing workers’ safety and health during the decommissioning of nuclear power plants (NPPs) is an important procedure in terms of occupational radiation exposure (ORE). Optimizing the radiation exposure through the “As Low As Reasonably Achievable (ALARA)” principle is a very important procedure...

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Autores principales: Kim, Juyoul, Tseren, Batbuyan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7432528/
https://www.ncbi.nlm.nih.gov/pubmed/32722235
http://dx.doi.org/10.3390/ijerph17155346
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author Kim, Juyoul
Tseren, Batbuyan
author_facet Kim, Juyoul
Tseren, Batbuyan
author_sort Kim, Juyoul
collection PubMed
description Assessing workers’ safety and health during the decommissioning of nuclear power plants (NPPs) is an important procedure in terms of occupational radiation exposure (ORE). Optimizing the radiation exposure through the “As Low As Reasonably Achievable (ALARA)” principle is a very important procedure in the phase of nuclear decommissioning. Using the VISIPLAN 3D ALARA planning tool, this study aimed at assessing the radiological doses to workers during the dismantling of the reactor pressure vessel (RPV) at Kori NPP unit 1. Fragmentation and segmentation cutting processes were applied to cut the primary component. Using a simulation function in VISIPLAN, the external exposure doses were calculated for each work operation. Fragmentation involved 18 operations, whereas segmentation comprised 32 operations for each fragment. Six operations were additionally performed for both hot and cold legs of the RPV. The operations were conducted based on the radioactive waste drum’s dimensions. The results in this study indicated that the collective doses decreased as the components were cut into smaller segments. The fragmentation process showed a relatively higher collective dose compared to the segmentation operation. The active part of the RPV significantly contributed to the exposure dose and thus the shielding of workers and reduced working hours need to be considered. It was found that (60)Co contained in the stainless steel of the reactor vessel greatly contributed to the dose as an activation material. The sensitivity analysis, which was conducted for different cutting methods, showed that laser cutting took a much longer time than plasma cutting and contributed higher doses to the workers. This study will be helpful in carrying out the occupational safety and health management of decommissioning workers at Kori NPP unit 1 in the near future.
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spelling pubmed-74325282020-08-24 Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1 Kim, Juyoul Tseren, Batbuyan Int J Environ Res Public Health Article Assessing workers’ safety and health during the decommissioning of nuclear power plants (NPPs) is an important procedure in terms of occupational radiation exposure (ORE). Optimizing the radiation exposure through the “As Low As Reasonably Achievable (ALARA)” principle is a very important procedure in the phase of nuclear decommissioning. Using the VISIPLAN 3D ALARA planning tool, this study aimed at assessing the radiological doses to workers during the dismantling of the reactor pressure vessel (RPV) at Kori NPP unit 1. Fragmentation and segmentation cutting processes were applied to cut the primary component. Using a simulation function in VISIPLAN, the external exposure doses were calculated for each work operation. Fragmentation involved 18 operations, whereas segmentation comprised 32 operations for each fragment. Six operations were additionally performed for both hot and cold legs of the RPV. The operations were conducted based on the radioactive waste drum’s dimensions. The results in this study indicated that the collective doses decreased as the components were cut into smaller segments. The fragmentation process showed a relatively higher collective dose compared to the segmentation operation. The active part of the RPV significantly contributed to the exposure dose and thus the shielding of workers and reduced working hours need to be considered. It was found that (60)Co contained in the stainless steel of the reactor vessel greatly contributed to the dose as an activation material. The sensitivity analysis, which was conducted for different cutting methods, showed that laser cutting took a much longer time than plasma cutting and contributed higher doses to the workers. This study will be helpful in carrying out the occupational safety and health management of decommissioning workers at Kori NPP unit 1 in the near future. MDPI 2020-07-24 2020-08 /pmc/articles/PMC7432528/ /pubmed/32722235 http://dx.doi.org/10.3390/ijerph17155346 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Kim, Juyoul
Tseren, Batbuyan
Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1
title Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1
title_full Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1
title_fullStr Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1
title_full_unstemmed Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1
title_short Occupational ALARA Planning for Reactor Pressure Vessel Dismantling at Kori Unit 1
title_sort occupational alara planning for reactor pressure vessel dismantling at kori unit 1
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7432528/
https://www.ncbi.nlm.nih.gov/pubmed/32722235
http://dx.doi.org/10.3390/ijerph17155346
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