The current research summarizes recent developments performed within the PSI BEPU methodology and the corresponding results on the SPERT-III RIA experiments. In this regard, three main studies have been carried out. First, an uncertainty breakdown study has been performed in order to identify the dominant nuclear data and to quantify their respective contributions to the overall uncertainties of the parameters of interest. On the other hand, the second study was devoted to assess the impact of considering the effect of cross section perturbation (limited for the time being to U-238 capture) in the resonance self-shielding calculation, known as the implicit effect, on different parameters’ uncertainties in SPERT-III RIA transient. Finally, the third study was conducted with the main goal to assess the impact of kinetic parameter uncertainties, such as delayed neutron yields and associated decay constants, on the overall uncertainties.

The uncertainty quantification results of the first study, based on the ENDF/B-VII.1 library, showed that, for steady-state, the first dominant contributor to the overall uncertainties of the static reactivity worth and k-eff is U-235 nubar, followed by U-238 then U-235 capture cross sections. However, for the transient, the first dominant contributor to the overall uncertainties, in e.g. total power and reactivity, is the U-238 inelastic scattering. More interestingly, it was found that, the second dominant contribution to the overall power uncertainty, during the initial excursion phase, is due to the U-235 nubar, while during the power reversal phase, the U-238 capture becomes the second dominant contribution, and even the first one by the end of the transient. Moreover, results of the second study demonstrated a clear systematic decrease of the uncertainty of all parameters due to the inclusion of the implicit effect. In steady state, due to the impact of the implicit effect, the Doppler coefficient relative uncertainty could be reduced up to 30%, which is reflected in the transient, especially in the reversal phase of the power excursion where Doppler effect plays a key role, by a systematic decrease of the relative uncertainty of total power and other parameters. Finally, in the third study, the estimated uncertainties, regarding both steady-state and transient parameters, have shown systematic larger values due to kinetic parameter uncertainties compared to those due to the other nuclear data.

当前的研究总结了 PSI BEPU 方法中的最新发展以及 SPERT-III RIA 实验的相应结果。在这方面，已经进行了三项主要研究。首先，进行了不确定性分解研究，以确定主要核数据并量化它们各自对感兴趣参数的整体不确定性的贡献。另一方面，第二项研究致力于评估在共振自屏蔽计算中考虑横截面扰动（暂时仅限于 U-238 捕获）的影响，称为隐式效应，对不同的SPERT-III RIA 瞬态参数的不确定性。最后，进行了第三项研究，主要目标是评估动力学参数不确定性的影响，

基于 ENDF/B-VII.1 库的第一项研究的不确定性量化结果表明，对于稳态，静态反应性值和 k-eff 的整体不确定性的第一个主要影响因素是 U-235 nubar，然后是 U-238，然后是 U-235 捕获横截面。然而，对于瞬态，总体不确定性的第一个主要贡献者，例如总功率和反应性，是 U-238 非弹性散射。更有趣的是，发现在初始偏移阶段对整体功率不确定性的第二个主要贡献是由于 U-235 nubar，而在功率反转阶段，U-238 捕获成为第二个主要贡献，甚至第一个在瞬态结束时。而且，第二项研究的结果表明，由于包含了隐性效应，所有参数的不确定性明显系统地降低。在稳态下，由于隐性效应的影响，多普勒系数的相对不确定性可以降低高达30%，这体现在瞬态上，特别是在多普勒效应起关键作用的功率偏移的反转阶段，通过系统降低总功率和其他参数的相对不确定性。最后，在第三项研究中，与其他核数据相比，由于动力学参数的不确定性，关于稳态和瞬态参数的估计不确定性显示出系统性更大的值。由于隐性效应的影响，多普勒系数的相对不确定性可以降低高达30%，这体现在瞬态上，特别是在多普勒效应起关键作用的功率偏移的反转阶段，通过系统性降低总功率和其他参数的相对不确定性。最后，在第三项研究中，与其他核数据相比，由于动力学参数的不确定性，关于稳态和瞬态参数的估计不确定性显示出系统性更大的值。由于隐性效应的影响，多普勒系数的相对不确定性可以降低高达30%，这体现在瞬态上，特别是在多普勒效应起关键作用的功率偏移的反转阶段，通过系统性降低总功率和其他参数的相对不确定性。最后，在第三项研究中，与其他核数据相比，由于动力学参数的不确定性，关于稳态和瞬态参数的估计不确定性显示出系统性更大的值。通过系统降低总功率和其他参数的相对不确定性。最后，在第三项研究中，与其他核数据相比，由于动力学参数的不确定性，关于稳态和瞬态参数的估计不确定性显示出系统性更大的值。通过系统降低总功率和其他参数的相对不确定性。最后，在第三项研究中，与其他核数据相比，由于动力学参数的不确定性，关于稳态和瞬态参数的估计不确定性显示出系统性更大的值。