Fukushima Daiichi Nuclear Power Plant Unit 2 accident analysis considering the thermal stratification and containment leakage

Le résumé fourni par la source

In 2011, during the Fukushima Daiichi Nuclear Power Plant accident, it was reported that several Units of containment vessel failed, and large quantity of radionuclides was released into the environment, however, the details of accident progression with core melt, reactor and containment vessel failure, still has significant uncertainties. Especially for the Unit 2, even though initial core cooling was successful, the cooling system was eventually lost and experienced a severe accident with large release of the fission product into the environment. To clarify these uncertainties in the accident scenario, considering the latest information and several insights, the latest accident scenario for Unit 2 is studied using the severe accident code, Modular Accident Analysis Program (MAAP, owned by EPRI), in this study. It is shown that Unit 2 would result in the thermal stratification in the containment vessel water which affected the containment pressure behaviour during the early phase of the accident. Conversely, it is also possible that containment vessel leakage happened to decrease the containment pressure during the later phase of the accident.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.