250MW球床模块式高温气冷堆进水事故研究

Water Ingress Accident of 250 MW Pebble-Bed Modular High-Temperature Gas-Cooled Reactor

基于250 MW球床模块式高温气冷堆(HTR-PM)的初步设计,以高温气冷堆专用系统分析软件TINTE程序为主要工具,对蒸汽发生器1根传热管双端断裂设计基准的进水事故进行了分析,研究了反应堆温度和压力的变化特性、球床石墨的腐蚀率以及安全阀开启所造成的可燃气体排放等。此外,还分析了风机挡板关闭失效情况下堆内温度分布差异所造成的自然循环对事故后果的影响。计算结果表明:在蒸汽发生器1根传热管双端断裂、最大进水量600 kg情况下,事故后燃料元件的最高温度远低于设计限值,化学反应所引起的石墨腐蚀不会造成反应堆结构强度的破坏和燃料元件的意外破损,释放到反应堆舱室的可燃气体含量也不存在爆炸危险。

Based on the preliminary design of 250 MW Pebble-bed Modular High-Temperature Gas-cooled Reactor(HTR-PM),the design basis accident(DBA) of two-area broken of single heat-exchange tube was analyzed by using TINTE,a special system analysis program for high-temperature gas-cooled reactors.Some safety relevant concerns,such as the fuel temperature and primary loop pressure,the graphite corrosion mass,the explosive gas releasing amount,as well as the natural convection influence under the condition of the failure of the blower baffle shut down,were studied.The calculation results indicate that,in the DBA of two-area broken of single heat-exchange tube of a steam generator and the consequent maximal water ingress amount of 600 kg,the maximal fuel temperature keeps far below the design limit 1 620 ℃.The results also show that the slight amount of graphite corrosion will not damage the reactor structure and the fuel element,and there is no potential explosive risk caused by the opening of the safety valve.