Vasiliev Alexander, Herrero Jose, Pecchia Marco, Rochman Dimitri, Ferroukhi Hakim, Caruso Stefano
Paul Scherrer Institute (PSI), 5232 Villigen PSI, Switzerland.
National Cooperative for the Disposal of Radioactive Waste (NAGRA), 5430 Wettingen, Switzerland.
Materials (Basel). 2019 Feb 5;12(3):494. doi: 10.3390/ma12030494.
This paper presents preliminary criticality safety assessments performed by the Paul Scherrer Institute (PSI) in cooperation with the Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra) for spent nuclear fuel disposal canisters loaded with Swiss Pressurized Water Reactor (PWR) UO₂ spent fuel assemblies. The burnup credit application is examined with respect to both existing concepts: taking into account actinides only and taking into account actinides plus fission products. The criticality safety calculations are integrated with uncertainty quantifications that are as detailed as possible, accounting for the uncertainties in the nuclear data used, fuel assembly and disposal canister design parameters and operating conditions, as well as the radiation-induced changes in the fuel assembly geometry. Furthermore, the most penalising axial and radial burnup profiles and the most reactive fuel loading configuration for the canisters were taken into account accordingly. The results of the study are presented with the help of loading curves showing what minimum average fuel assembly burnup is required for the given initial fuel enrichment of fresh fuel assemblies to ensure that the effective neutron multiplication factor, k e f f , of the canister would comply with the imposed criticality safety criterion.
本文介绍了保罗·谢尔研究所（PSI）与瑞士放射性废物处置国家合作社（Nagra）合作，对装载瑞士压水堆（PWR）UO₂乏燃料组件的乏核燃料处置罐进行的初步临界安全评估。针对现有两种概念对燃耗信用申请进行了审查：仅考虑锕系元素以及考虑锕系元素加裂变产物。临界安全计算与尽可能详细的不确定性量化相结合，考虑了所用核数据、燃料组件和处置罐设计参数及运行条件的不确定性，以及燃料组件几何形状的辐射诱导变化。此外，相应地考虑了对处置罐最不利的轴向和径向燃耗分布以及最易反应的燃料装载配置。研究结果借助装载曲线呈现，这些曲线表明对于给定初始燃料富集度的新鲜燃料组件，需要达到何种最低平均燃料组件燃耗，以确保处置罐的有效中子增殖系数k eff符合规定的临界安全准则。
