先进非能动压水堆核电站燃料组件轴向燃耗分布研究

Study of the axial burnup profiles for passive advanced PWR

燃料组件的轴向燃耗分布以及末端效应是燃耗信任制技术应用中的难点。基于先进非能动压水堆核电站的运行模式及组件设计特点,结合可能的燃料管理策略,统计轴向两端使用低富集度抑制区的乏燃料组件,生成轴向燃耗包络线。以AP1000堆型的乏燃料贮存单元为例,通过分析统计,证明生成的轴向燃耗包络线用于临界安全分析是保守的。在此基础上,详细研究燃料组件顶部的低富集度抑制区对末端效应的贡献,并对燃料组件进行设计改进,减小至消除末端效应,为简化乏燃料组件相关的临界安全分析提供了一个方法。相关研究工作及成果,是先进非能动压水堆核电站乏燃料组件相关的设施设备的临界安全设计的基础,可为其他堆型的相应研究提供参考和借鉴。

The axial burnup profiles of the fuel assemblies and the associated end effect play an important role in burnup credit （BUC）.Based on the operational strategy and the fuel assemblies’characteristics of the passive advanced PWR,as well as the possible fuel management schemes, the burnup information of the spent fuel assemblies including low enrichment axial blankets is summarized,and the bounding axial burnup profile is generated.The spent fuel storage cell model of AP1000 is used to statistically evaluate the adequacy of the bounding profile,and the results demonstrate that the bounding axial burnup profile is conservative for criticality analyses.And the impact of the axial blankets on the end effect is studied in detail.Based on the results,fuel assemblies are improved to mitigate and eliminate the end effect,which provides a method to simplify the criticality analyses.The results can be used for the criticality＆amp;nbsp;analyses related to the spent fuel assemblies of the passive advanced PWR,and the study can be referenced by other PWRs.