二回路耗汽运行对船用堆全部电源丧失事故进程缓解分析

针对船用核动力装置的特点，建立了船用堆一、二回路及控制系统的RELAP5模型，用RELAP5/MOD3.2程序对典型船用堆经济巡航工况下发生全部电源丧失事故进行模拟，分析了4种耗汽工况对事故进程的缓解效果。分析表明：事故后合理的耗汽运行方案能明显延缓事故进程，延缓时间为小时级别；耗汽量越小，二回路设备运行时间越长，二回路热阱持续时间也越长，一回路事故进程越缓慢。但太小的耗汽量会引起事故过程中蒸汽发生器（SG）二次侧水位过高甚至满水，进而威胁二回路设备的正常运行。同时，二回路设备数量众多，不同设备的最低运行汽量也不尽相同，应选择最有用和最低耗汽量的设备耗汽运行。本研究能对实际船用堆事故下的应急处理提供参考。

Analysis of Mitigation Effect of Steam-Exhaust Operation of the Secondary Circuit to Ship Reactor Blackout Accident

According the characteristics of ship reactor, the RELAP5 models for its primary circuit and the secondary circuit were established, the ship reactor blackout accident under the economy headway condition was simulated using RELAP5/MOD3.2 code, and the mitigation effects of four different steam-exhaust schemes to the accident process were analyzed. The results show that the reasonable steam-exhaust scheme can mitigate the accident remarkably, and the delay time is about hour level; the less the steam is consumed, the longer the operation time of the equipment of the secondary circuit is, the longer the time of the heat sink of the primary circuit can last, and the slower the accident process will be. However, too little steam-exhaust flux will lead to steam generator (SG) water level excessively high or even brimming which will be a threat to normal operation of the devices in the secondary circuit. Meanwhile, there are many devices in the secondary circuit, and the limits to the minimum steam flux to operate the devices are different. Then, the most useful device with the lowest steam-exhaust flux should be chosen as the steam-exhaust operation equipment. The study can provide a reference for the emergent treatment during the ship reactor blackout accident.