Analysis of High-Pressure Core Melt Severe Accidents in PWR Nuclear Power Plant

The high-pressure core melt accidents in PWR nuclear power plant which cover most of the severe accidents, have large potential risk. According to the probabilistic safety analysis (PSA) reports of Chinese 900 MW PWR nuclear power plant, the paper selected five typical severe accidents with high-pressure core melt, such as TMLB′, LOFW-ATWS, MSLB, SBLOCA and SGTR. The progressions and results of these accidents were analyzed by using SCDAP/RELAP5 code. According to the calculation results, these typical accidents can induce large risk of high-pressure melt-spray event (HPME) and direction containment heat (DCH), which may arose the early failure of containment. Thus, it is very necessary to implement the primary depressurization strategies.