一回路腐蚀产物在灵活性燃料管理模式下的沉积行为及源项水平分析

Analysis of the Primary Corrosion Product Deposition Behavior and Radioactivity Level under Flexible Fuel Management Strategies

压水堆一回路腐蚀产物的沉积和迁移,不仅会降低燃料包壳传热效率,增加源项水平,还可能导致轴向功率异常偏移等现象,影响反应堆安全稳定运行。为适应电网需求变化和提高经济性,越来越多的反应堆采用更加先进且灵活的燃料管理策略。为研究不同换料策略下一回路腐蚀产物的沉积行为及源项水平,本文针对某百万千瓦级压水堆分别采用18个月换料、16/20个月交替换料和24个月换料模式开展了分析,并从控制一回路腐蚀产物沉积和放射性的角度给出了最优的燃料管理策略。研究结果表明,24个月换料模式的堆芯污垢(Chalk Rivers Unidentified Deposit,CRUD)总量最少、冷却剂源项水平最低,16/20个月交替换料模式的CRUD总量最多、冷却剂源项水平最高。综合考虑腐蚀控制和辐射防护,24个月换料模式具有一定的优越性。

The deposition of corrosion products in the PWR primary circuit will not only reduce the heat transfer efficiency and increase the radioactivity level, but also lead to abnormal axial power deviation of core, which will seriously affect the safety of nuclear reactors. For better adapting to the change of power grid demand and improving economy,more and more reactors adopt more advanced and flexible fuel management strategies. In order to study the deposition behavior and radioactivity level of corrosion products in the primary circuit under different refueling strategies, this paper analyzes the 18-month refueling mode, 16/20-month alternate refueling mode and 24-month refueling mode respectively for a 1000 MWe PWR, and gives the optimal flexible fuel management strategy from the perspective of controlling deposition and radioactivity. The results show that the total CRUD amount and coolant radioactivity level are the least in 24-month refueling mode, compared to the highest in 16/20-month refueling mode. Considering corrosion controlling and radiation protection, the 24-month refueling mode has advantages.