Mixed uranium plutonium oxides (MOx) are currently used as nuclear fuel in thermal fission reactors and are the leading candidate for use in solid fuelled fast reactors given a wealth of irradiation data from research and prototype systems. Spark plasma sintering (SPS) has been shown to reduce the sintering temperature and time required to manufacture UO₂ fuel pellets and may benefit MOx production through the more efficient retention of volatile minor actinides (MAs) such as AmO₂ in the manufacture of these fuels. In this study we have examined SPS as an alternative field assisted sintering route to UO₂ and MOx fuel manufacture on surrogate (U_0.93,Ce_0.07)O₂ prepared by a micronized master blend (MIMAS) type process. SPS has been shown to produce pellets of high density, > 95% TD at sintering temperatures of 1573 K and hold time of 5 min, comparable to equivalent pellets produced through conventional sintering at 1973 K for 5 h. The formation of Ce-rich regions has been measured showing the size distribution of Ce-rich particles in SPS Ce-MOx is similar to conventionally sintered Ce-MOx and are appropriate for MOx fuel specifications. However, a significant difference is observed in the Ce content of the Ce-rich particles which remain close to their primary blend composition, as well as having a high degree of heterogeneity within the Ce-rich regions. The effect of the shortened sintering temperatures and times on other microstructural properties are also revealed.

混合铀钚氧化物 (MOx) 目前在热裂变反应堆中用作核燃料，鉴于来自研究和原型系统的大量辐照数据，混合铀钚氧化物 (MOx) 是用于固体燃料快堆的主要候选材料。火花等离子体烧结 (SPS) 已被证明可以降低制造 UO ₂燃料芯块所需的烧结温度和时间，并且可以通过在这些燃料的制造过程中更有效地保留挥发性微量锕系元素 (MA)，例如 AmO ₂来促进MOx 的生产. 在本研究中，我们研究了 SPS 作为替代场辅助烧结途径，以替代 (U _0.93 ,Ce _0.07 )O ₂制造UO ₂和 MOx 燃料通过微粉化母混料 (MIMAS) 型工艺制备。SPS 已被证明可以在 1573 K 的烧结温度和 5 分钟的保持时间下生产高密度、> 95% TD 的球团，与通过在 1973 K 下传统烧结 5 小时生产的等效球团相媲美。已测量出富 Ce 区域的形成，表明 SPS Ce-MOx 中富 Ce 颗粒的尺寸分布类似于传统烧结的 Ce-MOx，并且适用于 MOx 燃料规格。然而，在富 Ce 颗粒的 Ce 含量上观察到显着差异，这些颗粒保持接近其主要混合成分，并且在富 Ce 区域内具有高度的不均匀性。还揭示了缩短的烧结温度和时间对其他微观结构特性的影响。