Key Nuclear Data Impacting Reactivity in Advanced Reactors
Key Nuclear Data Impacting Reactivity in Advanced Reactors
复制标题
影响先进反应堆反应性的关键核数据
DOI：
10.2172/1639325
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
W. Wieselquist
中科院分区：
文献类型：
--
作者：
F. Bostelmann;G. Ilas;W. Wieselquist
目前在整个工业中正在开发的先进反应堆概念在几何形状、材料和操作条件方面，以及因此在反应堆物理行为方面，与轻水反应堆（LWR）设计显著不同。鉴于非轻水堆的运行经验有限，反应堆物理的准确模拟和相关不确定性的量化对于确保先进反应堆概念在适当的安全裕度内运行至关重要。核数据是反应堆物理分析中输入不确定性的主要来源。作为橡树岭国家实验室（ORNL）正在进行的一个项目的一部分，正在评估核数据不确定性对与先进反应堆安全相关的关键优值的影响。确定了与每种选定的先进反应堆技术的反应堆安全分析有关的关键核数据，并评估了它们对重要关键优值的影响。审查了现有的先进反应堆规范，查阅了ORNL和其他研究机构的研究结果，并分析了现有的评估核数据库。本报告总结了燃料中核素的关键核数据，以及其他重要数据，包括慢化剂，冷却剂和所考虑的先进反应堆结构的各种材料中的散射和中子捕获。对于所考虑的使用低浓缩铀燃料的先进反应堆，由于缺乏专门针对这些新系统的现有研究，轻水堆研究的结果提供了有关核数据的见解。确定的主要标称缺失数据包括用于熔盐反应堆（MSR）分析的热散射数据和135 m厚的横截面数据。核数据不确定性方面的主要差距是高温气冷堆和慢化MSR系统的热散射数据的不确定性缺失，以及角分布的不完全不确定性，特别是对于快谱系统，如钠冷快堆，快熔盐反应堆和热管反应堆。此外，还发现，应特别注意不同的评估核数据库发布之间的横截面和不确定性差异，因为核数据的显着差异可能导致反应性计算的重大差异，即使是众所周知的核素。
Advanced reactor concepts currently being developed throughout the industry are significantly different from light water reactor (LWR) designs with respect to geometry, materials, and operating conditions, and consequently, with respect to their reactor physics behavior. Given the limited operating experience with non-LWRs, the accurate simulation of reactor physics and the quantification of associated uncertainties are critical for ensuring that advanced reactor concepts operate within the appropriate safety margins. Nuclear data are a major source of input uncertainties in reactor physics analysis. As part of an ongoing project at Oak Ridge National Laboratory (ORNL), the effects of nuclear data uncertainties on key figures of merit associated with advanced reactor safety are being assessed for selected advanced reactor technologies. Key nuclear data relevant for reactor safety analysis for each selected advanced reactor technology were identified, and their impact on important key figures of merit was assessed. Available advanced reactor specifications were reviewed, results from studies performed at ORNL and other research institutions were consulted, and available evaluated nuclear data libraries were analyzed. This report summarizes the key nuclear data for nuclides in the fuel, as well as other significant data, including scattering and neutron capture in various materials for the moderator, coolant, and structure of the considered advanced reactors. For the considered advanced reactors that use low-enriched uranium (LEU) fuel, results from LWR studies provided insight into relevant nuclear data given the lack of available studies specifically addressing these new systems. The major nominal missing data that were identified consist of thermal scattering data and 135m Xe cross section data for molten salt reactor (MSR) analysis. The identified major gaps with respect to nuclear data uncertainties are missing uncertainties of thermal scattering data for high temperature gas-cooled reactors and moderated MSR systems, and incomplete uncertainties on angular distributions in particular for fast spectrum systems, such as sodium-cooled fast reactors, fast molten salt reactors, and heat pipe reactors. Furthermore, it was found that special attention should be paid to cross section and uncertainty differences between different evaluated nuclear data library releases, because significant differences in nuclear data that can lead to major differences in reactivity calculations were found, even for well-known nuclides.