水冷聚变堆活化腐蚀产物源项分析程序开发

Program Development for Source Term Analysis of Activated Corrosion Product in Water-cooled Fusion Reactor

对于采用水冷方式的聚变堆,主要的放射性源项是水冷回路中的活化腐蚀产物,它会对反应堆的屏蔽设计、人员防护以及事故后果产生重要影响。本文为水冷聚变堆开发活化腐蚀产物源项分析程序CATE,该程序基于两项均匀模型构建浓度平衡方程组,全面考虑了活化腐蚀产物在水冷回路中的主要行为,包括腐蚀、释放、溶解、沉积、活化、衰变、净化等,并采用Runge-Kutta方法对浓度平衡方程组进行数值求解。使用CATE程序对国际热核聚变实验堆(ITER)的偏滤器冷却回路进行建模仿真,计算得到了活化腐蚀产物的成分和放射性活度在冷却剂中和管壁上的分布以及随时间的变化规律。与国际上同类程序PACTITER和TRACT相比,CATE程序的计算结果无论是在数值上还是趋势上都是合理的,可为ITER和CFETR(中国聚变工程实验堆)等的技术评审提供源项数据支持,在增加相应数据库后,还可应用于液态金属冷却反应堆的源项分析。

Activated corrosion products （ACPs） in the cooling loops are the dominant radioactive source in water-cooled fusion reactors, and make a great effect on radiation shielding design, personnel protection, and consequences of nuclear accidents. In this paper, a code named CATE （corrosion, activation and transport evaluation） was developed to simulate the production and transport process of ACPs in water-cooled fusion reactors. Based on a two-phase homogeneous model, the concentration balance equations were built, in which the main behaviors of ACPs in the cooling loop were covered, including corrosion, release, dissolution, deposition, activation, decay and purification. For solving the concentration balance equations numerically, the classical method of Runge-Kutta was adopted. The cooling loop in the divertor of ITER （International Thermonuclear Experimental Reactor） was simulated to test the CATE code, and the composition and radioactivity of ACPs respectively in the coolant and on the pipe wall were calculated. These results were compared with those from other two codes PACTI- TER and TRACT, which presented a consistency in quantity and a reasonable variation tendency over time. Therefore, CATE can be used to calculate the source term of ACPs in ITER and CFETR （China Fusion Engineering Test Reactor）, as well as the liquid metal cooled reactor after adding the corresponding database in the future.