在发生反应堆严重事故时,熔融物堆内滞留(In-Vessel Retention,IVR)是一种非常有效和重要的严重事故缓解措施。反应堆压力容器下封头对于IVR策略的成功实施具有重要的作用。在IVR发生过程中,下封头处于高温环境中,其主要失效形式为蠕变...在发生反应堆严重事故时,熔融物堆内滞留(In-Vessel Retention,IVR)是一种非常有效和重要的严重事故缓解措施。反应堆压力容器下封头对于IVR策略的成功实施具有重要的作用。在IVR发生过程中,下封头处于高温环境中,其主要失效形式为蠕变失效。下封头一旦发生失效则有可能导致放射性物质释放到环境中。因此,为了确保IVR策略的成功实施,防止放射性物质泄漏,有必要开发一种有效的反应堆压力容器下封头的热蠕变模型从而对下封头进行深入分析。本文应用薄壳理论并结合诺顿-贝利蠕变方程开发了LHTCM(Lower Head Thermal Creep Module)模型,并使用四种失效准则分别对下封头的完整性进行评估。最终将LHTCM模型集成到一体化严重事故分析程序ISAA中对OLHF(OECD Lower Head Failure)实验进行了验证计算。通过对LHTCM模型中四种失效准则的分析,最终采用Larson-Miller准则的LHTCM模型预测的下封头失效时间与实验数据的相对误差仅在2.0%以内,并且其预测的下封头最底部伸长量与Kachanov准则等其他三种判据相比更加符合实验结果。结果表明:本文开发的LHTCM模型能够准确地预测下封头的蠕变行为,所计算的下封头失效时间、位置以及底部伸长量等与实验结果符合很好。展开更多
A historical review of in-vessel melt retention （IVR） is given, which is a severe accident mitigation mea- sure extensively applied in Generation III pressurized water reactors （PWRs）. The idea of IVR actually ori...A historical review of in-vessel melt retention （IVR） is given, which is a severe accident mitigation mea- sure extensively applied in Generation III pressurized water reactors （PWRs）. The idea of IVR actually originated from the back-fitting of the Generation 11 reactor Loviisa WER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse APIO00, the Korean APR1400 as well as Chinese advanced PWR designs HPRIO00 and CAP1400. The most influential phe- nomena on the IVR strategy are in-vessel core melt evolution, the heat fluxes imposed on the vessel by the molten core, and the external cooling of the reactor pressure vessel （RPV）. For in-vessel melt evolution, past focus has only been placed on the melt pool convection in the lower plenum of the RPV; however, through our review and analysis, we believe that other in-vessel phenomena, including core degradation and relocation, debris formation, and coolability and melt pool formation, may all contrib- ute to the final state of the melt pool and its thermal loads on the lower head. By looking into previous research on relevant topics, we aim to identify the missing pieces in the picture. Based on the state of the art, we conclude by proposing future research needs.展开更多
文摘在发生反应堆严重事故时,熔融物堆内滞留(In-Vessel Retention,IVR)是一种非常有效和重要的严重事故缓解措施。反应堆压力容器下封头对于IVR策略的成功实施具有重要的作用。在IVR发生过程中,下封头处于高温环境中,其主要失效形式为蠕变失效。下封头一旦发生失效则有可能导致放射性物质释放到环境中。因此,为了确保IVR策略的成功实施,防止放射性物质泄漏,有必要开发一种有效的反应堆压力容器下封头的热蠕变模型从而对下封头进行深入分析。本文应用薄壳理论并结合诺顿-贝利蠕变方程开发了LHTCM(Lower Head Thermal Creep Module)模型,并使用四种失效准则分别对下封头的完整性进行评估。最终将LHTCM模型集成到一体化严重事故分析程序ISAA中对OLHF(OECD Lower Head Failure)实验进行了验证计算。通过对LHTCM模型中四种失效准则的分析,最终采用Larson-Miller准则的LHTCM模型预测的下封头失效时间与实验数据的相对误差仅在2.0%以内,并且其预测的下封头最底部伸长量与Kachanov准则等其他三种判据相比更加符合实验结果。结果表明:本文开发的LHTCM模型能够准确地预测下封头的蠕变行为,所计算的下封头失效时间、位置以及底部伸长量等与实验结果符合很好。
文摘A historical review of in-vessel melt retention （IVR） is given, which is a severe accident mitigation mea- sure extensively applied in Generation III pressurized water reactors （PWRs）. The idea of IVR actually originated from the back-fitting of the Generation 11 reactor Loviisa WER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse APIO00, the Korean APR1400 as well as Chinese advanced PWR designs HPRIO00 and CAP1400. The most influential phe- nomena on the IVR strategy are in-vessel core melt evolution, the heat fluxes imposed on the vessel by the molten core, and the external cooling of the reactor pressure vessel （RPV）. For in-vessel melt evolution, past focus has only been placed on the melt pool convection in the lower plenum of the RPV; however, through our review and analysis, we believe that other in-vessel phenomena, including core degradation and relocation, debris formation, and coolability and melt pool formation, may all contrib- ute to the final state of the melt pool and its thermal loads on the lower head. By looking into previous research on relevant topics, we aim to identify the missing pieces in the picture. Based on the state of the art, we conclude by proposing future research needs.
