This study presents the first thermal conductivity measurements performed on neutron irradiated U₃Si₂ dispersion fuel cladded in an aluminum matrix (in a plate geometry). These were performed via a novel set-up which consists of a thermo-reflectance apparatus, known as the thermal conductivity microscope (TCM), deployed in a shielded glovebox. Thermal conductivity was measured across different fuel particles at various positions along the plate length and correlated to the local burnup. Back scattered electron images were collected at each position and analyzed to obtain estimates of the local porosity. It was shown that the thermal conductivity of the irradiated fuel particles is approximately 25% to 35% lower compared to the unirradiated material. A solid-state physics model was used to interpret the measured data. According to the model the degradation in thermal conductivity is consistent with the presence of insulating, fission gas filled pores or bubbles as well as loss of long-range order due to irradiation induced amorphization.

本研究首次对中子辐照的 U ₃ Si ₂进行热导率测量包裹在铝基体中的分散燃料（板状几何形状）。这些是通过一种新颖的装置进行的，该装置由一个热反射装置组成，称为热导显微镜 (TCM)，部署在一个屏蔽手套箱中。在沿板长度的不同位置测量不同燃料颗粒的热导率，并与局部燃耗相关。在每个位置收集背散射电子图像并进行分析以获得局部孔隙率的估计值。结果表明，与未经辐照的材料相比，经辐照的燃料颗粒的热导率低约 25% 至 35%。固态物理模型用于解释测量数据。根据模型，热导率的降低与绝缘的存在一致，