反应堆内局部自然循环对非能动余热排出的影响

Influence of Local Natural Circulation on Passive Residual Heat Removal in Nuclear Reactor

为研究反应堆堆内局部自然循环对非能动余热排出的影响,利用改进的RELAP5/MOD3.2程序对核动力装置及非能动余热排出系统进行数学建模与理论研究,并利用试验数据进行了校核。研究表明:在核动力装置自然循环运行条件下,由于反应堆上封头旁流及反应堆入口漏流通道的存在,在反应堆活性区、上封头、环腔及下腔室之间构成了局部自然循环流动现象;在主回路自然循环能力较弱时,堆内产生的局部自然循环流动占优,反应堆衰变热无法顺利带出。

The nuclear power plant and passive residual heat removal system were modeled and investigated with the advanced code developed from RELAP5/MOD3.2 code,for analyzing the influence of local natural circulation on the passive residual heat removal in nuclear reactor.The simulation results were validated with experimental data.The results indicate that the local natural circulation occurs in the connected region consists of reactor radiation zone,upper head,annular channel and lower plenum in case of natural circulation operation,due to the upper head by-passing flow and the leak flow at the core inlet.As the natural circulation capability is weak,the local natural circulation in the core is so significant that the decay heat can not be removed successfully.