ABSTRACT The new critical assembly STACY will be able to contribute to the validation of criticality calculations related to the fuel debris. The experimental core designs are in progress in the frame of JAEA/IRSN collaboration. This paper presents the method applied to optimize the design of the new STACY core to measure the criticality characteristics of pseudo fuel debris that simulated Molten Core Concrete Interaction (MCCI) of the fuel debris. To ensure that a core configuration is relevant for code validation, it is important to evaluate the reactivity worth of the main isotopes of interest and their keff sensitivity to their cross sections. In the case of the fuel debris described in this study, especially for the concrete composition, silicon is the nucleus with the highest keff sensitivity to the cross section. For this purpose, some parameters of the core configuration, were adjusted using optimization algorithm to find efficiently the optimal core configurations to obtain high sensitivity of silicon capture cross section. Based on these results, realistic series of experiments for fuel debris in the new STACY could be defined to obtain an interesting feedback for the MCCI. This methodology is useful to design other experimental conditions of the new STACY.

中文翻译：

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临界配置设计方法应用于新型STACY燃料碎片实验设计

摘要 新的关键组件 STACY 将有助于验证与燃料碎片相关的临界计算。实验核心设计正在 JAEA/IRSN 合作框架内进行。本文介绍了用于优化新 STACY 堆芯设计的方法，以测量模拟燃料碎片的熔核混凝土相互作用 (MCCI) 的伪燃料碎片的临界特性。为确保核心配置与代码验证相关，重要的是评估感兴趣的主要同位素的反应性价值及其对其横截面的 keff 敏感性。在本研究中描述的燃料碎片的情况下，特别是对于混凝土成分，硅是对横截面具有最高 keff 敏感性的核。以此目的，核心配置的一些参数，使用优化算法进行调整，以有效地找到最佳核心配置，以获得硅捕获截面的高灵敏度。基于这些结果，可以定义新 STACY 中燃料碎片的一系列现实实验，以获得对 MCCI 的有趣反馈。这种方法对于设计新 STACY 的其他实验条件很有用。