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

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.