应急设施可居留性分析的严重事故源项初步探讨

以先进压水堆核电厂为对象,开展了适用于应急设施可居留性评价的严重事故源项分析方案研究,覆盖了堆芯释放、安全壳内自然去除、放射性物质向环境释放途径等。结合非能动安全壳冷却系统的特征,重点研究了安全壳可能的失效行为,论证了安全壳在事故后24h和72h失效工况的辐射影响。结果表明:两种工况放射性释放水平均达到了INES(国际核事件分级)第6级的水平,属于比较严重的核事故;133 Xe、131I为主导核素组的主导核素,所释放的133 Xe介于WASH-1400中PWR2~PWR4之间的水平,131I介于PWR5~PWR6之间水平。同时,以国内某沿海厂址为例,评价了两种工况下应急指挥中心(EOF)工作人员的有效剂量,均可满足100mSv的剂量限值要求。

Preliminary Study of Severe Accident Source Term for Emergency Facility Habitability

Based on advanced pressurized water reactor nuclear plant,research on severe accident source terms for emergency facility habitability was carried out,including core inventory release,nuclide removal in containment and release pathways to environment.Considering the feature of passive containment cooling system,the prospective failure behaviors for containment were mainly studied,and radiation influences based on containment failure at 24 h and 72 h were estimated.The results show that the radioactive release levels for both conditions reach level 6 of INES (international nuclear and radiological event scale).The radioactive fractions of 133Xe released into environment lie between PWR2-PWR4 of WASH-1400,and the radioactive fractions of 131I released into environment lie between PWR5-PWR6 of WASH-1400.Meanwhile,based on the coastal site in China,operator doses of emergency operation facility (EOF) were assessed,which meet the dose limit value of 100 mSv.