Deploying high thermal conductive materials as additives to UO₂ has been highlighted due to their enhanced thermal performance as a potential candidate of Accident-Tolerant Fuels (ATFs). Herein, we investigate thermomechanical behaviors of UO₂ – 5 vol% Mo fuel pellets with a sandwiched configuration where Mo layers are positioned on the top and bottom of a UO₂ part. The successfully fabricated sandwich-type UO₂ fuel pellets with an inclusion of 5 vol% Mo by using a conventional sintering method exhibit up to 3.0 and 2.5 times higher effective thermal conductivities at 800 °C than standard UO₂ and dispersion-type UO₂ – 5 vol% Mo fuel pellets, due to the effective heat transfer characteristics in the Light Water Reactor (LWR) fuel. Accordingly, the sandwich-type fuel pellets not only effectively reduce the thermal stress gradients across the pellets, but also significantly decrease the maximum tensile hoop stresses of fuel pellets. Finally, the radial deformation behaviors of the sandwich-type fuel pellets are also investigated under a simulated irradiation condition, showing that an hourglass-shaped deformation of UO₂ pellets are considerably mitigated.

由于增强的热性能使其成为耐事故燃料（ATF）的潜在候选者，已经突出了将高导热材料用作UO _2的添加剂。在此，我们调查UO的热机械行为₂ -一个夹构型，其中的Mo层被定位在UO的顶部和底部的5体积％的Mo燃料芯块₂的一部分。通过使用常规烧结方法成功制备的夹杂型UO ₂燃料芯块，其中Mo的含量为5 vol％，在800°C时的有效热导率是标准UO ₂和分散型UO _2的3.0到2.5倍–由于轻水反应堆（LWR）燃料具有有效的传热特性，因此Mo燃料颗粒的体积分数为5％。因此，夹心型燃料芯块不仅有效地减小了整个芯块的热应力梯度，而且还显着降低了燃料芯块的最大拉伸环向应力。最后，还在模拟辐照条件下研究了夹心型燃料芯块的径向变形行为，表明UO ₂芯块的沙漏形变形被大大减轻。