ABSTRACT

The applicability of Monte–Carlo calculations is examined for the analyses of light-water-moderated and light-water-reflected cores at the Kyoto University Critical Assembly with the use of the experimental data of criticality, reactivity, and reaction rates. For the well-thermalized cores, criticality demonstrates the dependence of eigenvalue bias on the neutron spectrum at a critical state, using MCNP6.2 with ENDF/B-VII.1 and JENDL-4.0. Also, reactivity and reaction rate analyses provide reasonable results within acceptable allowance of uncertainty between experiments and calculations. Furthermore, no significant difference is evident between two major nuclear data libraries. From the results, issues of overestimating criticality need to be highlighted in the well-thermalized cores composed of the HEU fuel and the light-water moderator.

摘要

在京都大学临界大会上，利用临界、反应性和反应速率的实验数据，检验了蒙特卡罗计算对轻水慢化和轻水反射岩心的分析的适用性。对于热化良好的核心，临界性表明特征值偏差在临界状态下对中子谱的依赖性，使用 MCNP6.2 与 ENDF/B-VII.1 和 JENDL-4.0。此外，反应性和反应速率分析在实验和计算之间可接受的不确定性允许范围内提供合理的结果。此外，两个主要核数据库之间没有明显差异。从结果来看，在由 HEU 燃料和轻水慢化剂组成的良好热化堆芯中，需要强调高估临界的问题。