Phenomena Identification Ranking Table (PIRT) Study for Influencing Factors of Aerosol Deposition in Passive Containment of Pressurized Water Reactor

压水堆发生事故后安全壳内高温高压的大气会载带放射性气溶胶到内部换热器传热管周围，形成抽吸效应并循环流动，气溶胶被卷吸进入传热管管间时将造成大量沉积。根据非能动安全壳内大气夹带气溶胶运动时的机理，本研究开展了不同气溶胶行为机理的沉降速率分析，建立了非能动安全壳气溶胶沉降影响因素的重要性排序表(PIRT)，识别出安全壳热的大气的局部冷却和内部换热器传热管附近的大气抽吸是影响非能动安全壳内气溶胶沉降的重要机理，应在非能动安全壳内气溶胶的模化实验和理论模拟中需要予以重点关注。After an accident occurred in pressurized water reactor, the high-temperature and high-pressure atmosphere inside the containment could carry radioactive aerosols to the vicinity of the heat exchanger’s heat transfer tubes, creating a suction effect and circulating flow. When aerosols were drawn into the gaps of the heat transfer tubes, it could lead to significant deposition. Based on the mechanisms of aerosol movement in the non-active containment atmosphere, this study conducted an analysis of the settling rates of different aerosol behavior mechanisms and established a Phenomena identification Ranking Table (PIRT) for the factors affecting aerosol settling in the passive containment. It identified that the local cooling of the hot atmosphere in the containment and the atmospheric suction near the heat transfer tubes of the internal heat exchanger are important mechanisms influencing aerosol settling in the non-active containment, which should be given special attention in both experimental modeling and theoretical simulations of aerosols in the non-active containment.