Recycling and burning minor actinides (MA, e.g., americium, neptunium) in mixed-oxide (MOX) nuclear fuel is a strategic option for fast reactor concepts of Generation IV, especially considering the current interest in the ultimate radioactive waste management and sustainability improvement by better use of natural resources. Among the fuel properties, thermal conductivity and melting temperature are pivotal since they determine, respectively, the fuel temperature profile and the fundamental safety limit on the margin to fuel melting, hence impacting on the overall fuel performance under irradiation and allowing the safe irradiation of the fuel pin. Nevertheless, the available literature about Am- or Np-containing MOX is currently scarce, both regarding experimental data and models. Moreover, state-of-the-art fuel performance codes (FPCs, e.g., TRANSURANUS) do not account for the effects of minor actinides on MOX fuel properties. This work presents original correlations for thermal conductivity and melting temperature of minor actinide-MOX fuels, i.e., (U, Pu, Am, Np)O_2-x, derived based on the available literature and accessible data, which are herein extensively reviewed. The assessment of the novel correlations is first performed in a statistical way, evaluating the regressor p-values which indicate their significance with respect to the available experimental dataset used for the fitting procedure. Additionally, the novel correlations for MA-MOX are assessed against both measured and calculated data (from Molecular Dynamics simulations), yielding an accuracy in line with the already existing correlations and with the state-of-the-art experimental uncertainties. Finally, the potential integral impact of a homogeneous minor actinide content in the fuel is illustrated on the basis of a fuel pin fast-ramped up to fuel melting during the HEDL P-19 irradiation experiment.

在混合氧化物 (MOX) 核燃料中回收和燃烧微量锕系元素（MA，例如镅、镎）是第四代快堆概念的战略选择，特别是考虑到当前对最终放射性废物管理和可持续性改进的兴趣更好地利用自然资源。在燃料特性中，热导率和熔化温度是关键，因为它们分别决定燃料温度曲线和燃料熔化裕度的基本安全极限，从而影响辐照下的整体燃料性能并允许安全辐照燃料棒。然而，关于含 Am 或 Np 的 MOX 的可用文献目前很少，无论是关于实验数据还是模型。此外，最先进的燃料性能代码（FPC，例如，TRANSURANUS) 没有考虑微量锕系元素对 MOX 燃料特性的影响。这项工作提出了微量锕系元素-MOX 燃料（即（U、Pu、Am、Np）O 的热导率和熔化温度的原始相关性_2-x，基于可用文献和可访问数据得出，在此进行了广泛审查。新相关性的评估首先以统计方式进行，评估回归量 p 值，该值表明它们相对于用于拟合程序的可用实验数据集的重要性。此外，MA-MOX 的新相关性根据测量数据和计算数据（来自分子动力学模拟）进行评估，产生的准确性与现有相关性和最先进的实验不确定性一致。最后，基于在 HEDL P-19 辐照实验期间燃料细棒快速上升至燃料熔化，说明了燃料中均质次锕系元素含量的潜在整体影响。