摘要
本文应用MELCOR程序,通过建立全厂详细的模型,对福岛第一核电厂2号机组在地震发生后4天(96h)内的严重事故进程进行了模拟分析并与电厂实测数据进行了比较。基于文中假设的模拟计算得到的趋势与电厂现有实测数据较为一致,分析结果表明:假设TORUS隔间内海水淹没一半时,作为新增的外部热阱与RCIC系统耦合工作,可有效地将堆芯衰变热排出,并延缓了安全壳压力上升。96h内安全壳压力未达到过滤排放系统开启值;RCIC系统在事故发生后近3天失效,此后4.6h操纵员通过开启主蒸汽泄压阀(SRV)对反应堆进行快速卸压,然而堆芯在消防水注入时接近完全裸露,继而发生强烈锆水反应;6h内产氢量达到近800kg。事故后期堆芯通道依然维持可冷却几何形状,最终操纵员通过开启第2组泄压阀对反应堆进行卸压,消防水泵得以有效向反应堆注入冷却水,堆芯重新淹没并冷却。
The severe accident progression within first 4days for Fukushima Daiichi NPP unit 2(1F2)was simulated with application of MELCOR code.Detailed modeling and system response of the whole plant were made to achieve it.The simulated results were compared with those monitored.The simulation results based on assumption agree well with those measured.When coupled with RCIC system,the TORUS room,which was initially flooded to half height of TORUS outside,acted as an additional external heat sink,could effectively remove reactor decay heat,as well as counteract the PCV pressure rise.Within 96 h,the PCV pressure did not reach the opening set point of containment filter and venting system.The RCIC system became ineffective about threedays after the accident occurred.For 4.6hafter RCIC failure,operator started to depressurize the reactor system by manually stuck-opening of SRV.Nevertheless,the core was almost total uncovered when fire water began to be pumped into reactor,intense Zr-water reaction took place as a result.Within 6h,nearly 800 kg of H2 was generated and released from the core.While the reactor core channel still kept its coolable geometry in the late phase of accident.Finally,when second SRV was opened to depressurize the reactor to more extent,and allowed higher flowrate of fire water to be pumped into reactor,the reactor was reflooded and cooled down by the end of 4days.
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2014年第S1期427-432,共6页
Atomic Energy Science and Technology
基金
国家科技重大专项资助项目(2013ZX06004008-005)
