压水堆严重事故后安全壳内辐射环境计算分析

Calculation and Analysis for the Radiation Condition in the Containment of PWR after Severe Accident

为了确保有效的缓解严重事故,需要对用于缓解和监测严重事故进程的重要设备、仪表在严重事故环境下的可用性进行评估。而温度、压力、湿度、辐射等参数是可用性评估的重要输入条件。本文针对百万千瓦级压水堆核电机组,参考美国核管会发布的《轻水堆核电厂事故源项》(NUREG-1465)关于严重事故后放射性物质的释放阶段和释放份额的假设,计算出事故后由堆芯释放到安全壳内的放射性源项。对于放射性物质在安全壳内的分布,不考虑喷淋和泄漏的影响,计算并分析了严重事故后安全壳内的γ和β辐射环境条件,并与AP1000的设备鉴定源项进行了对比分析。本文的计算对于设备和仪表在严重事故后的可用性分析以及其所需耐受的辐射条件具有重要的参考意义。

In order to mitigate severe accident effectively, validation of equipment and instrument after severe accident need to be evaluated. The temperature, pressure, humidity and radiation are key parameters for the validation evaluation. For the source term released from the molten core to the containment, NUREG-1465 was adopted for PWR. Effect of spray and leakage on concentrations of radioactive nuclides in the containment was ignored. In this paper, γ and β radiation condition in the containment after severe accident were calculated and analyzed, which is very important to validation evaluation of equipment and instrument after severe accident.