水冷聚变堆主回路活化产物源项计算分析

Calculation and analysis of activation products source term in water-cooled fusion reactor primary circuit

水冷聚变堆中结构材料活化腐蚀产物和冷却剂活化产物是正常运行工况下的最主要放射性来源,也是反应堆运行及维护过程中工作人员辐照剂量的直接来源。本文使用CATE V2.1程序对国际热核聚变实验堆(International Thermonuclear Experimental Reactor,ITER)LIM-OBB(Limiter-Out-Board Baffle)冷却回路的活化腐蚀产物和水活化产物进行模拟计算,并根据CATE模拟得到的放射性活度通过点核积分程序分别计算正常运行1.2 a及停堆15 d的剂量率。计算结果表明,反应堆运行期间冷却剂活化产物比活度和剂量率远大于结构材料活化腐蚀产物,而停堆后冷却剂活化产物迅速衰变完,结构材料的活化腐蚀产物成为比活度和剂量率的主要来源。

Background： Activated corrosion products （ACPs） from structure materials and coolant activation products are the dominant radiation hazard in water-cooled fusion reactor under normal operation conditions, and directly determine the occupational radiation exposure （ORE） during operation and maintenance. Purpose： The aim is to quantitatively analysis source term of activation products in International Thermonuclear Experimental Reactor （ITER）. Methods： CATE V2.1 is used to simulate the ACPs from structure materials and coolant activation products in the ITER blanket circuit, and then the dose rate of the LIM-OBB （Limiter-Out-Bboard Baffle） cooling loop operating for 1.2 a, and 15 d after shutdown is calculated by point kernel code ARShield. Results ＆ Conclusion： Under operation conditions, the specific activity and dose rate of the coolant activation products are much higher than those of ACPs from structure material, while after shutdown, the coolant activation products decay out rapidly, and the ACPs from structure material become the main contributor to specific activity and dose rate.