Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident

Intentional depressurization and cavity flooding are two important measures in current severe accident management guidelines (SAMGs). An extreme scenario of an extended station blackout (ESBO), when electric power is unavailable for more than 24 hours, actually occurred in the Fukushima Daiichi acci...

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Main Authors: Nan Jiang, Minjun Peng, Wei Wei, Tenglong Cong
Format: Article
Language:English
Published: Wiley 2018-01-01
Series:Science and Technology of Nuclear Installations
Online Access:http://dx.doi.org/10.1155/2018/8680406
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author Nan Jiang
Minjun Peng
Wei Wei
Tenglong Cong
author_facet Nan Jiang
Minjun Peng
Wei Wei
Tenglong Cong
author_sort Nan Jiang
collection DOAJ
description Intentional depressurization and cavity flooding are two important measures in current severe accident management guidelines (SAMGs). An extreme scenario of an extended station blackout (ESBO), when electric power is unavailable for more than 24 hours, actually occurred in the Fukushima Daiichi accident and attracted lots of attention. In an ESBO, the containment spray cannot be activated for condensation, and, thus, cavity flooding will generate a large amount of steam, which, ironically, overpressurizes the containment to failure before the reactor vessel is melted through. Therefore, consideration of these conflicting issues and the ways in which plants operate is crucial for strengthening the strategies outlined in SAMGs. In this paper, the effects of intentional depressurization and cavity flooding in an ESBO for a representative 900 MW second-generation pressurized water reactor (PWR) are simulated with MAAP4 code. Diverse scenarios with different starting times of depressurization and water injection are also compared to summarize the positive and negative impacts for accident mitigation. The phenomena associated with creep ruptures, hydrogen combustion, corium stratification, and cavity boiling are also analyzed in detail to strengthen our understanding of severe accident mechanisms. The results point out the facility limitations of second-generation PWRs which can improve existing SAMGs.
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spelling doaj-art-a45e544cb3364f9598ed6d7a67bf1c1d2025-08-20T03:38:24ZengWileyScience and Technology of Nuclear Installations1687-60751687-60832018-01-01201810.1155/2018/86804068680406Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe AccidentNan Jiang0Minjun Peng1Wei Wei2Tenglong Cong3Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001, ChinaFundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001, ChinaChina Nuclear Power Operation Technology Corporation LTD, Wuhan 430000, ChinaFundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin 150001, ChinaIntentional depressurization and cavity flooding are two important measures in current severe accident management guidelines (SAMGs). An extreme scenario of an extended station blackout (ESBO), when electric power is unavailable for more than 24 hours, actually occurred in the Fukushima Daiichi accident and attracted lots of attention. In an ESBO, the containment spray cannot be activated for condensation, and, thus, cavity flooding will generate a large amount of steam, which, ironically, overpressurizes the containment to failure before the reactor vessel is melted through. Therefore, consideration of these conflicting issues and the ways in which plants operate is crucial for strengthening the strategies outlined in SAMGs. In this paper, the effects of intentional depressurization and cavity flooding in an ESBO for a representative 900 MW second-generation pressurized water reactor (PWR) are simulated with MAAP4 code. Diverse scenarios with different starting times of depressurization and water injection are also compared to summarize the positive and negative impacts for accident mitigation. The phenomena associated with creep ruptures, hydrogen combustion, corium stratification, and cavity boiling are also analyzed in detail to strengthen our understanding of severe accident mechanisms. The results point out the facility limitations of second-generation PWRs which can improve existing SAMGs.http://dx.doi.org/10.1155/2018/8680406
spellingShingle Nan Jiang
Minjun Peng
Wei Wei
Tenglong Cong
Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident
Science and Technology of Nuclear Installations
title Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident
title_full Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident
title_fullStr Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident
title_full_unstemmed Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident
title_short Strategy Evaluation for Cavity Flooding during an ESBO Initiated Severe Accident
title_sort strategy evaluation for cavity flooding during an esbo initiated severe accident
url http://dx.doi.org/10.1155/2018/8680406
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AT minjunpeng strategyevaluationforcavityfloodingduringanesboinitiatedsevereaccident
AT weiwei strategyevaluationforcavityfloodingduringanesboinitiatedsevereaccident
AT tenglongcong strategyevaluationforcavityfloodingduringanesboinitiatedsevereaccident