中文摘要：

以某船用压水堆为研究对象，采用MELCOR程序建立事故分析模型，研究大破口失水事故叠加全船断电严重事故下放射性裂变产物的行为，着重分析了惰性气体和CsI的释放、迁移、滞留特点及在堆舱内的分布。结果表明，83．12％惰性气体从堆芯释放出来，并主要存在于堆舱的气空间；83．08％的CsI从堆芯释放出来，其中，72．66％滞留在堆坑熔融物与一回路内，27．34％释放到堆舱内，并主要溶解于舱底水池中。本文分析结果可为舱室剂量评估、核应急管理提供依据。

英文摘要：

Using MELCOR code, the accident analysis model was established for a ship reactor. The behaviors of radioactive fission products were analyzed in the case of severe accident induced by large break loss of coolant accident coincident with ship blackout. The research mainly focused on the behaviors of release, transport, retention and the final distribution of inert gas and CsI. The results show that 83.12% of inert gas releases from the core, and the most of inert gas exists in the containment. About 83.08% of CsI release from the core, 72.66% of which is detained in the debris and the primary system, and 27.34% reference for the evaluation of releases into the containment. The results can give a cabin dose and nuclear emergency management.