基于动态贝叶斯网络的乏燃料后处理核应急情景分析

Nuclear emergency scenario analysis for spent fuel reprocessingbased on dynamic Bayesian network

为提升乏燃料后处理核事故应急准备与响应能力,针对核事故应急演变路径的不确定性、情景分析在突发事件应急决策的重要性、演变过程的复杂性以及组织实施难等问题,构建基于知识元理论的乏燃料后处理核事故应急情景。选取事件、致灾体、承灾体和应急响应为组成要素,建立基于动态贝叶斯网络(DBN)方法的乏燃料后处理核应急动态情景推演分析模型,计算关键情景的发生概率、推演情景的发展趋势、分析演化规律与路径。以马雅克乏燃料后处理厂的高放废液贮槽爆炸为例,开展基于知识元和DBN的乏燃料后处理核事故应急情景分析方法的过程推演,并分析结果。结果表明:应急冷却供水丧失发生的概率为73%,高放废液贮槽爆炸发生的概率为86%,放射性核素通过多种途径转移到动植物产品和饮用水发生的概率为87%,部分地区有长寿命放射性核素沉积发生的概率为89%,事件平息与消亡发生的概率为72%;事故污染空气、土壤、河流的发生概率分别为89%、85%、81%,对公众健康和安全有影响的发生概率为86%。情景演化过程与后处理贮槽爆炸事故应急发展,以及对公众、环境的影响一致,验证了该模型的可行性和有效性。

To improve the emergency preparedness and response capabilities of spent fuel reprocessing nuclear accidents,a spent fuel reprocessing nuclear accident emergency scenario based on knowledge meta was proposed to address the uncertainty of the nuclear accident emergency evolution process,the importance of scenario analysis in emergency response decision-making,the complexity of the evolution process,and the difficulty of organization and implementation.The disaster event,causative agent,causal agent,and emergency response were determined,and then a dynamic scenario model for spent fuel reprocessing nuclear emergencies based on a DBN was developed to calculate the occurrence probability of key scenarios,evaluate the development trend of the scenarios,and analyze the evolution laws and paths.Taking the explosion of the high-release liquid storage tank of the Mayak spent fuel reprocessing plant as an example,the process of deduction of the scenario analysis method of the spent fuel reprocessing nuclear accident based on the knowledge meta theory and DBN was performed,and the results were further analyzed.The results showed that:the loss probability of emergency cooling water supply was 73%,the probability of explosion of the high-release waste liquid storage tank was 86%,the probability of radioactive nuclides transferred to animal and plant products and drinking water through multiple pathways was 87%,the probability of long-lived radioactive nuclides deposition in part of the area was 89%,and the probability of the event calming down and dying out was 72%.The probability of the accident contaminating the air,soil,and river was 89%,85%,and 81%,respectively.The probability of affecting public health and safety was 86%.The scenario evolution process is consistent with the emergency response development of the reprocessing storage tank explosion accident and its impact on the public and the environment,validating the model performance.