核电站严重事故后果概率安全评价方法研究

核电站严重事故后果概率安全评价(PSA)是采用概率论的方法对核电站放射性后果进行分析,并定量给出放射性物质对核电站周围公众的健康效应影响。以国内某压水堆核电站为参考厂址,建立合适的场外后果分析模型。采用分层抽样方法对参考厂址1a的气象数据进行抽样,源项和释放特征等数据取自二级PSA的研究结果。利用事故后果评价程序对核电站严重事故后果进行计算,并用概率论方法对结果进行评估。通过计算将各事故和事故谱的场外个人剂量表示为CCDF曲线和总频率-剂量曲线,再用概率论方法得到不同距离处个人剂量超过指定剂量的条件概率;也可用此方法对确定烟羽应急计划区的安全准则中所描述的"大多数严重事故序列"进行量化。

Study on Severe Accident Consequence Probability Safety Assessment Method of Nuclear Power Plant

The probability safety assessment (PSA) method of nuclear power plant (NPP) severe accident consequence is to apply probability theory to analyze radioactive consequences of nuclear power plant and assess quantitatively the public health effects around nuclear power plants. Taking a domestic PWR NPP as a reference site, an appropriate off-site consequence analysis model was established. The stratified sampling method was used for meteorological sampling within a year meteorological data, and the radioactive source term and release characteristics data were from level two PSA. Using nuclear power plant accident consequence assessment code to calculate the off-site severe accident consequences, the results obtained by probability method were assessed. The off-site individual dose of each accident and accident spectrum can be expressed as CCDF curve and total frequency-dose curves by means of calculation, and according to the probability assessment method, the conditional probability of individual doses exceeding the specified dose can be obtained. Also this method can be used to quantify the most severe accident sequences described in the safety standards for determining the plume emergency planning zone.