核反应堆RPV扩展区域注量率计算关键影响因素分析
Analysis of Key Factors Influencing Flux Calculation for RPV Extended Beltline Region
摘要: 核反应堆压力容器(RPV)快中子注量率是评估压力容器结构完整性的关键参数，反应堆运行时间延长和功率提升可能导致RPV扩展区域注量水平超过设计限值，离散纵标法(SN方法)是目前用于计算RPV快中子注量率的主要方法之一。建立压水堆扩展区域屏蔽计算模型，基于ARES离散纵标屏蔽计算程序，从数值计算方法和物理模型参数两方面开展RPV扩展区域注量率计算关键参数影响分析。研究结果表明，在RPV传统区域计算结果稳定的前提下，扩展区域轴向高度644.53 cm处，1.2 cm × 1.2 cm与1.0 cm × 1.0 cm两种径向网格尺寸的快中子注量率计算结果最大偏差可达40.41%；相较于求积组阶数为S16的计算结果，求积组阶数为S8的最大偏差达42.32%；功率分布计算结果显示，RPV扩展区域快中子注量率计算需采用堆芯外围组件的Pin-by-Pin的功率分布方式。输入参数计算分析结果表明，相比于RPV传统区域，燃耗深度、堆芯板成分、空腔宽度以及混凝土成分的变化对RPV扩展区域快中子注量率计算结果的影响更加显著。参数敏感性分析确定了RPV扩展区域注量率计算关键影响因素，对RPV结构完整性评估具有重要意义。
Abstract: Fast neutron flux in the Reactor Pressure Vessel (RPV) is a critical parameter for assessing the structural integrity. With reactor operating life extension and power uprates, the neutron fluence level in the RPV extended beltline region may exceed the design limit. The discrete ordinates method (the SN method) is currently one of the principal methods used to calculate the fast neutron flux in the RPV. An shielding calculation model for the RPV extended beltline region of a pressurized water reactor is established, and based on the ARES discrete ordinates shielding code, the effects of key parameters on neutron fluence calculations in the RPV extended beltline region are analyzed from both the perspectives of numerical methods and physical model parameters. The results indicate that, on the premise of stable calculation results in the RPV traditional beltline region, the maximum deviation between 1.2 cm × 1.2 cm and 1.0 cm × 1.0 cm radial mesh sizes in the extended beltline region attain 40.41% at an axial height of 644.53 cm. Compared with the calculation results of S16, the maximum deviation of S8 reaches 42.32%. Power distribution calculation results show that flux calculations require the Pin-by-Pin power distribution of peripheral assemblies. The analysis of input parameters shows that, compared with the traditional RPV beltline region, changes in burnup depth, core barrel composition, cavity width, and concrete composition have a more pronounced impact on the calculation results of fast neutron fluence in the RPV extended beltline region. The parameter sensitivity analysis identifies the key factors affecting neutron fluence calculations in the RPV extended beltline region, which is of great significance for evaluating the structural integrity of the RPV.
文章引用：冯子明, 张斌. 核反应堆RPV扩展区域注量率计算关键影响因素分析[J]. 核科学与技术, 2026, 14(2): 50-66. https://doi.org/10.12677/nst.2026.142005

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