压水堆核电厂一回路冷却剂系统中锕系核素质量评估方法研究

Research on Evaluation Method of Actinide Nuclide Activities in Primary Coolant System of Pressurized Water Reactor Nuclear Power Plant

为评估压水堆核电厂燃料包壳破损时的工作人员辐射风险和燃料包壳破损程度,基于特征物理量建立一回路冷却剂系统中锕系核素质量评估方法。本文基于锕系核素的生成和迁移机理,建立了一回路冷却剂系统中锕系核素的平衡方程组,并选取3种易监测的特征物理量用以评估锕系核素向一回路冷却剂系统的释放量及其分布,并建立了一回路冷却剂系统中锕系核素质量的评估方法。然后分别采用国内在役压水堆核电厂无燃料包壳破损和有燃料包壳破损的实测数据对建立的评估方法进行了验证,验证结果表明:建立的评估方法可在无燃料包壳破损和有燃料包壳破损的情况下对一回路冷却剂系统中锕系核素质量进行评估,评估结果和预期符合。本文研究成果可为压水堆核电厂运行期间一回路冷却剂系统中锕系核素质量及其分布评估提供指导,从而优化后端的工作人员防护措施,降低辐射风险。

In order to evaluate the radiation risk of workers and the damage degree of fuel cladding in PWR nuclear power plant,it is necessary to improve the evaluation approach of actinide nuclide activities in the primary coolant systems based on characteristic physical quantities.Based on the generation and migration mechanism of actinide nuclides,the balance equations of actinide nuclides in primary coolant system are established,and three easy-to-monitor characteristic physical quantities are selected to evaluate the release and distribution of actinide nuclides to the primary coolant system.Hence,the evaluation approach of actinide nuclide activities in primary coolant systems is established.The evaluation approach is validated by the measurement data without and with fuel cladding damage from in-service nuclear power plant in China,respectively.The validation results show that the established approach is applicable for the evaluation of actinide nuclide activities in the primary coolant system without and with fuel cladding damage,and the evaluation results are in line with expectations.The results of this paper can provide guidance for the assessment of actinide nuclides and their distribution in the primary coolant system during the operation of PWR nuclear power plants,so as to optimize the back-end staff protection measures and reduce the radiation risk.