自然循环反应堆NHR-200Ⅱ失水事故初步研究

Preliminary Study on LOCA of Natural Circulation Reactor NHR-200Ⅱ

破口事故是压水堆最为关注的一类重要事故,其失水量与事故后果严重程度密切相关。NHR-200Ⅱ是由清华大学核能与新能源技术研究院经过多年研究和不断改进,设计的一种全功率自然循环低温供热反应堆,其设计中采用了多种先进的非能动和固有安全设计。本研究针对NHR-200Ⅱ反应堆,选取后果最为严重的控制棒引水管断裂且无法隔离事故,利用系统热工瞬态分析程序对事故过程进行了模拟和分析。结果表明,即使在最严重的破口失水事故下,NHR-200Ⅱ主回路中剩余的冷却剂始终能覆盖反应堆堆芯,并有效通过非能动余热载出系统带走堆芯热量,从而保证反应堆堆芯不会因裸露造成烧毁,这表明NHR-200Ⅱ具有很好的安全特性。

Loss of coolant accident(LOCA)is one of the most important accidents in PWR,and total water loss is closely related to the severity of accident consequences.The NHR-200Ⅱis a full-power natural circulation low-temperature nuclear heating reactor designed by Institute of Nuclear and New Energy Technology of Tsinghua University with many years of research and continuous improvement.Its design adopts a variety of advanced passive and inherent safety designs.For the NHR-200Ⅱreactor,the typical pipe rupture of hydraulic control rod driving system with isolation failure was selected to be simulated and analyzed by the thermal-hydraulic transient analysis program.The results show that the residual coolant in the primary circuit of NHR-200Ⅱcan cover the reactor core all the time even in the most serious loss of coolant accident,and the heat of reactor core could be carried away effectively by the passive decay heat removal system,which ensure that the reactor core would not be damaged due to lack of coolant.The result indicates that the NHR-200Ⅱhas good safety characteristics.