Abstract The reactivity of a fuel assembly including burnable absorbers can become the largest at low fuel burnup, so the accuracy of reactivity calculations for such systems is important. To investigate this issue, the impact of gadolinium isotopes’ nuclear data on neutron multiplication factor k is quantified. Sensitivities of k to nuclear data are calculated from 0 to 20 GWD/t for a BWR 3 × 3 multicell model. Sensitivity to gadolinium-157 (n, γ ) cross section becomes the largest at the zero burnup. Sensitivity to gadolinium-155 (n, γ ) cross sections takes the two largest values and the second one is observed around fuel burnup where the reactivity reaches its peak. Sensitivities are also calculated for BWR and PWR assemblies, and similar trends are observed. Finally, nuclear data-induced uncertainties of k are quantified. Gadolinium-157 contribution is the largest at zero burnup, and gadolinium-155 contribution is relatively important around fuel burnup corresponding to the reactivity peak.

中文翻译：

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中子倍增因子对反应燃耗峰值范围内轻水反应堆燃料组件钆同位素核数据的敏感性

摘要 包含可燃吸收器的燃料组件的反应性在低燃料燃耗时会变得最大，因此此类系统反应性计算的准确性很重要。为了研究这个问题，钆同位素的核数据对中子倍增因子 k 的影响进行了量化。对于 BWR 3 × 3 多池模型，k 对核数据的敏感性计算为 0 到 20 GWD/t。对钆 157 (n, γ ) 截面的敏感性在零燃耗处变得最大。对钆 155 (n, γ ) 截面的敏感性取两个最大值，第二个值在燃料燃烧附近观察到，此时反应性达到峰值。还计算了 BWR 和 PWR 组件的灵敏度，并观察到类似的趋势。最后，量化了由核数据引起的 k 的不确定性。