核设施退役过程中的辐射场重构与拆除路径优化

摘要

辐射场分布和路径选择是核设施退役过程中影响工作人员吸收剂量的主要因素.针对核设施退役过程中多源项的三维辐射场,采用点核积分的方法进行重构,重构结果与蒙特卡罗程序计算结果吻合很好,验证了点核积分法的可行性.将核退役拆除路径问题抽象为一种类旅行商问题数学模型,构造不同拆除路径下所受外照射剂量对应的剂量矩阵,根据辐射防护ALARA(As Low As Reasonably Achievable)原则,利用遗传算法进行寻优.对于多源项退役拆除实例,计算给出了最优化拆除路径和三维可视化显示,并对优化效果进行了讨论.设计开发了面向核设施退役过程的辐射场重构与拆除路径优化功能软件.%Background:Decommissioning nuclear facilities with less cost is a key part of nuclear reactor development, which mainly depends on the dismantling route based on the distribution of radiation field.Purpose:This study attempts to reconstruct the radiation field of decommissioning nuclear facilities and find out the optimal dismantling route.Methods:The method of point-kernel integration is adopted to reconstruct the three-dimensional radiation field of multi-source terms during the decommissioning of nuclear facilities and the results are compared with the Monte Carlo program. A functional software is designed and developed with functions of radiation field reconstruction and removal route optimization during the nuclear facility decommissioning process. The problem of optimizing dismantling route is abstracted to a mathematical model of the Traveling Salesman Problem (TSP), and the Dose Matrix under different routes are constructed. According to ALARA (As Low As Reasonably Achievable) principle of the radiation protection, the methodology is optimized by genetic algorithm.Results:The reconstructed radiation field is in good agreement with the result calculated by the Monte Carlo program. Upon the instance of decommissioning multi-source terms' removal, the optimal route and three-dimensional visualization are calculated and obtained, and the optimal results are discussed.Conclusion:The method of point-kernel integration and the TSP mathematical model can be used during nuclear decommissioning.