Nuclear Meltdown Relocation and Core Catcher Analysis
Nuclear meltdown with the potential human and environmental harm is one of the major accident hazard (MAH) faced by nuclear power plants. Limiting (or entirely avoiding) criticality events are the main design strategies for reactors of generations 3½ and 4 (Gen3½ and Gen4). These include ensuring n...
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| Format: | Article |
| Language: | English |
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Universidade Federal do Rio Grande
2023-12-01
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| Series: | Vetor |
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| Online Access: | https://periodicos.furg.br/vetor/article/view/15158 |
| _version_ | 1797374811060568064 |
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| author | Evald Bregu Stephen Aroh Ajah Jefferson Gomes |
| author_facet | Evald Bregu Stephen Aroh Ajah Jefferson Gomes |
| author_sort | Evald Bregu |
| collection | DOAJ |
| description |
Nuclear meltdown with the potential human and environmental harm is one of the major accident hazard (MAH) faced by nuclear power plants. Limiting (or entirely avoiding) criticality events are the main design strategies for reactors of generations 3½ and 4 (Gen3½ and Gen4). These include ensuring negative void and negative temperature coefficients (for both moderator and fuel) regardless of operational conditions, which provide a self-regulating mechanism that helps preventing accidents occurrence (i.e., to address safety and reliability aspects of Gen4’s goals). However, in severe accident scenarios (e.g. during loss-of-coolant, LOCA, events) where failure to extract heat from the reactor may lead to core degradation, strategies to mitigate reactor meltdown and relocation are critical in the design of safety protocols. This work aims to numerically investigate core relocation as an integrated multi-fluid and heat dynamics problem in which flow of melted materials (UO2, Zircaloy and graphite) are modelled through interface capturing/tracking methods. Two interface tracking/capturing methods were compared, the level-set volume of fluid method (VOF) in Ansys Fluent, and the compressive advection method (CAM) in Fluidity/ICFERST. Both methods are in good agreement for the core relocation simulation. An in-vessel core catcher (IVCC) of tungsten alloy was also proposed to demonstrate core degradation control strategy through cooling of the melted multi-materials. The IVCC was simulated with a multifluid model in Ansys Fluent, in a specified applied heat flux model. The thickness of the IVCC is 0.20 m and the heat flux used is 600 kW m-2. The tungsten material used was able to withstand both thermal and mechanical loads on the lower plenum by extracting decay heat from the corium.
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| first_indexed | 2024-03-08T19:11:07Z |
| format | Article |
| id | doaj.art-e7224ac14b894066bc23d4cb0f5e8c41 |
| institution | Directory Open Access Journal |
| issn | 0102-7352 2358-3452 |
| language | English |
| last_indexed | 2024-03-08T19:11:07Z |
| publishDate | 2023-12-01 |
| publisher | Universidade Federal do Rio Grande |
| record_format | Article |
| series | Vetor |
| spelling | doaj.art-e7224ac14b894066bc23d4cb0f5e8c412023-12-27T15:29:24ZengUniversidade Federal do Rio GrandeVetor0102-73522358-34522023-12-0133210.14295/vetor.v33i2.15158Nuclear Meltdown Relocation and Core Catcher AnalysisEvald Bregu0Stephen Aroh Ajah1Jefferson Gomes2University of AberdeenUniversity of AberdeenUniversity of Aberdeen Nuclear meltdown with the potential human and environmental harm is one of the major accident hazard (MAH) faced by nuclear power plants. Limiting (or entirely avoiding) criticality events are the main design strategies for reactors of generations 3½ and 4 (Gen3½ and Gen4). These include ensuring negative void and negative temperature coefficients (for both moderator and fuel) regardless of operational conditions, which provide a self-regulating mechanism that helps preventing accidents occurrence (i.e., to address safety and reliability aspects of Gen4’s goals). However, in severe accident scenarios (e.g. during loss-of-coolant, LOCA, events) where failure to extract heat from the reactor may lead to core degradation, strategies to mitigate reactor meltdown and relocation are critical in the design of safety protocols. This work aims to numerically investigate core relocation as an integrated multi-fluid and heat dynamics problem in which flow of melted materials (UO2, Zircaloy and graphite) are modelled through interface capturing/tracking methods. Two interface tracking/capturing methods were compared, the level-set volume of fluid method (VOF) in Ansys Fluent, and the compressive advection method (CAM) in Fluidity/ICFERST. Both methods are in good agreement for the core relocation simulation. An in-vessel core catcher (IVCC) of tungsten alloy was also proposed to demonstrate core degradation control strategy through cooling of the melted multi-materials. The IVCC was simulated with a multifluid model in Ansys Fluent, in a specified applied heat flux model. The thickness of the IVCC is 0.20 m and the heat flux used is 600 kW m-2. The tungsten material used was able to withstand both thermal and mechanical loads on the lower plenum by extracting decay heat from the corium. https://periodicos.furg.br/vetor/article/view/15158Nuclear reactor coreMeltdown relocationCore CatcherLower plenum |
| spellingShingle | Evald Bregu Stephen Aroh Ajah Jefferson Gomes Nuclear Meltdown Relocation and Core Catcher Analysis Vetor Nuclear reactor core Meltdown relocation Core Catcher Lower plenum |
| title | Nuclear Meltdown Relocation and Core Catcher Analysis |
| title_full | Nuclear Meltdown Relocation and Core Catcher Analysis |
| title_fullStr | Nuclear Meltdown Relocation and Core Catcher Analysis |
| title_full_unstemmed | Nuclear Meltdown Relocation and Core Catcher Analysis |
| title_short | Nuclear Meltdown Relocation and Core Catcher Analysis |
| title_sort | nuclear meltdown relocation and core catcher analysis |
| topic | Nuclear reactor core Meltdown relocation Core Catcher Lower plenum |
| url | https://periodicos.furg.br/vetor/article/view/15158 |
| work_keys_str_mv | AT evaldbregu nuclearmeltdownrelocationandcorecatcheranalysis AT stephenarohajah nuclearmeltdownrelocationandcorecatcheranalysis AT jeffersongomes nuclearmeltdownrelocationandcorecatcheranalysis |