压水堆核电站一回路^(16)N源项计算模型的优化

Optimized Calculation Model of ^(16)N Radiation Sources in Primary Coolant of PWR

^(16)N是压水堆一回路冷却剂中的主要活化产物,也是一回路中的主要辐射源。本文在传统^(16)N源项计算模型的基础上,根据堆芯内冷却剂的流向,考虑堆芯区域以及下降段区域的中子通量差异,将堆芯划分为活化区域以及反射区域,并建立了相应的计算模型,以典型三代压水堆核电站为例进行了计算与验证,计算结果与技术文件吻合良好,偏差在10%以内,验证了模型的正确性。最后分析了一回路典型部位的^(16)N平衡放射性活度浓度,发现在反应堆堆芯出口处最高,随着冷却剂流向逐步减少。研究结果表明,优化的计算模型可更准确计算压水堆核电站冷却剂的^(16)N源项,为分析反应堆一回路的辐射源项提供参考依据。

As the coolant is the main activated product passing through each activation region in the reactor vessel, the neutron in the region will activate the oxygen in water into activated product, such as16 N. 16N is the main product, and it is the most important radiation sources in the primary side. A 16N radiation sources model is established based on conventional method and primary coolant flow direction, dividing the core area into activation regions and reflection regions. To prove the validity of the calculation model, the integrative calculation of 16N radiation sources in the primary coolant was completed. The coolant typical ~6N model equilibrium radiation sources were analyzed. It finds out that the radiation sources are maximum at the core outlet, and are reduced along with the coolant. The study result shows that the optimized calculation model gives more accurate calculation for the 16 N sources.