Previously, the neutronics design of a small and compact linear breed-and-burn fast reactor (B&BR) was completed. The reactor produces 400 MWth power, and it can operate with excess reactivity of less than 1$ for more than 50 years without refuelling. As the blanket fuel, the spent nuclear fuel (SNF) from existing light water reactors (LWRs) is used to reduce the burden from the problematic long-lived isotopes in SNF. However, by loading massive nuclides at the initial core, the impact of nuclear data uncertainty on the reactivity calculation results of SNF-fuelled B&BR at the beginning of life (BOL) is expected to be significant because these nuclides have different credentials in evaluated nuclear data libraries. In this study, the impact of nuclear library uncertainty from ENDF/B-VII.0 and ENDF/B-VII.1 on reactivity calculation of B&BR is evaluated using the continuous-energy TSUNAMI-3D module in the SCALE6.2 code package. The uncertainty of reactivity calculation results of B&BR caused by the inaccuracy of two libraries is significant (more than 2000 pcm), mainly from the uncertainty of ^235,238U and ⁵⁶Fe cross section. The energy-dependent sensitivity profiles show that they are significant at the fast energy range. The uncertainty of coolant void reactivity (CVR) is about 18%, and that of fuel temperature coefficient (FTC) is about 15% of the reactivity effect. The top five contributions for CVR accounted for elastic scattering of ²³⁸U, capture of ^235,238U, and elastic scattering of ²³Na and ⁵⁶Fe. Meanwhile, the top contributors for FTC were accounted for elastic scattering of ²³⁸U and ⁵⁶Fe, capture of ²³⁵U, and elastic scattering of ⁹⁴Zr and ⁵⁷Fe. It is highly recommended to improve the accuracy of those isotopes’ cross sections at the high energy range to provide a more reliable reactivity calculation for the fast system.

中文翻译：

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用SCALE6.2代码研究钠冷线性增殖燃烧快堆核数据的敏感性和不确定性

此前，完成了小型紧凑型线性增殖燃烧快堆（B&BR）的中子学设计。该反应堆可产生 400 MWth 的电力，并且可以在不加燃料的情况下以低于 1 美元的过剩反应性运行 50 多年。作为覆盖层燃料，来自现有轻水反应堆 (LWR) 的乏核燃料 (SNF) 用于减轻 SNF 中存在问题的长寿命同位素的负担。然而，通过在初始堆芯加载大量核素，预计核数据不确定性对 SNF 燃料 B&BR 在生命初期 (BOL) 反应性计算结果的影响是显着的，因为这些核素在评估的核数据中具有不同的凭据图书馆。在本研究中，来自 ENDF/B-VII.0 和 ENDF/B-VII.1 的核库不确定性对 B& 反应性计算的影响 BR 使用 SCALE6.2 代码包中的连续能量 TSUNAMI-3D 模块进行评估。B&BR反应性计算结果因两个库不准确造成的不确定性很大（超过2000pcm），主要来自于^235,238 U 和⁵⁶ Fe 横截面。与能量相关的灵敏度曲线表明它们在快速能量范围内很重要。冷却剂无效反应性（CVR）的不确定性约为18%，燃料温度系数（FTC）的不确定性约为反应性效应的15%。CVR 的前五名贡献占²³⁸ U 的弹性散射、^235,238 U 的捕获以及²³ Na 和⁵⁶ Fe 的弹性散射。同时，FTC 的主要贡献者是²³⁸ U 和⁵⁶ Fe 的弹性散射、²³⁵ U 的捕获以及⁹⁴ Zr 和⁵⁷铁。强烈建议提高这些同位素在高能量范围内的横截面的准确性，以便为快速系统提供更可靠的反应性计算。