大亚湾核电站18个月换料的堆芯失水事故长期冷却分析研究

在失水事故长期冷却过程中，必须确定安全注射系统从冷段注射切换到冷热段同时注射的切换时间。这对避免反应堆堆芯硼结晶、堆芯因地坑硼浓度过低而引起重返临界有着十分重要的意义。介绍了大亚湾核电站18个月换料设计失水事故长期冷却分析，应用REFLET程序分析计算了失水事故后堆芯和地坑的硼浓度随时间的变化，给出了不同换料水箱硼浓度下的容许切换时间。当换料水箱硼浓度为2204mg/L时，操作员必须在6小时以前将安注由冷段注射切换到冷、热段同时注射的模式。

GNPS 18-Months Fuel Cycles Studies On Analyses of LOCA Long-term Core Cooling

It is necessary to determine switchover time to simultaneous cold and hot leg safety injection during LOCA long-term core cooling. It has a significant effect on avoiding boron crystallization in the core and any return to criticality. This paper introduces the analyses of LOCA long-term core cooling for Guang Dong Daya Bay Nuclear Power Station 18 Months Fuel Cycle Project. The boron concentrations in the reactor core and in the containment sump versus time during LOCA are calculated using REFLET computer code. The minimum and maximum allowable boron concentration in the refueling water storage tank as a function of switchover time are provided in the paper. The operator must change the SI configuration from cold injection model to simultaneous cold and hot leg safety injection before 6h when boron concentration in RWST is 2204 mg/L.