非能动安全壳冷却机制安全壳大气净化分析

 采用一体化严重事故分析工具,建立包括主冷却剂系统、专设安全设施、非能动安全壳冷却系统的事故分析模型,该模型耦合了核电厂热工水力、安全壳响应及裂变产物行为分析。研究了小破口失水事故(SB-LOCA)、大破口失水事故(LB-LOCA)以及主给水丧失事故(LOFW)始发严重事故序列下非能动安全壳冷却机制对安全壳大气的净化作用,对非能动安全壳空冷和水冷工况下对安全壳内气溶胶的去除行为进行了分析。通过无冷却、空冷有效、空冷和水冷同时有效的三种工况下气溶胶行为的比对分析,研究了冷却机制对扩散电泳和热电泳引起的气溶胶沉积。分析结果表明,非能动安全壳冷却机制可以增强气溶胶扩散电泳和热电泳的去除效应,相关分析可为严重事故管理导则的制定提供技术支持。

Analysis of Containment Aerosol Removal Induced by Passive Containment Cooling Mechanism

Based on an integrated severe accident analysis code, a severe accident analysis model is established to include the Reactor Coolant System (RCS), the Engineered Safeguard Facility (ESF) and the containment system, coupled with a thermo-hydraulic analysis, the containment response and the fission products behavior. A passive containment cooling system model is also built with consideration of the air convection cooling and the liquid film heat transfer. Three typical severe accidents induced by small break loss of the coolant accident (SB-LOCA), large break loss of the coolant accident (LB-LOCA) and loss of the feed water accident (LOFW) are considered with the containment atmosphere decontamination as a result of the passive containment cooling mechanism. For every sequence, three different cases are considered, which are the case without cooling, the case with air convection, and the case with air convection and liquid film. The aerosol behaviors for different cases are studied focusing on the volatile fission products and non-volatile fission products. The results show that the passive containment cooling mechanism can enhance the removal effect of diffusion phoresis and thermo-phoresis.