Helium cooled solid breeder blanket as an important blanket candidate of the Tokamak fusion reactor uses ceramic pebble bed for tritium breeding. Considering the poor effective thermal conductivity of the ceramic breeder pebble bed, thin structure of tritium breeder pebble bed is usually adopted in the blanket design. The container wall has a great influence on the thin pebble bed packing structure, especially for the assembly of mono-sized particles, and thin pebble bed will appear anisotropic effective thermal conductivity phenomenon. In this paper, thin ceramic pebble beds composed of 1 mm diameter $L{i}_{4}Si{O}_4$ particles are generated by the EDEM 2.7. The effective thermal conductivity of different thickness pebble beds in the three-dimensional directions are analyzed by three-dimensional thermal network method. It is observed that thin $L{i}_{4}Si{O}_4$ pebble bed showing anisotropic effective thermal conductivity under the practical design size. Normally, the effective thermal conductivity along the bed vertical direction is higher than the horizontal direction due to the gravity effect. As the thickness increases from 10 mm to 40 mm, the effective thermal conductivity of the pebble bed gradually increases.

氦冷固体增殖毯作为托卡马克聚变反应堆的重要候选毯使用陶瓷球床进行氚增殖。考虑到陶瓷增殖球床的有效导热性较差，毯子设计中通常采用薄型氚增殖球床结构。容器壁对薄球床填料结构有很大影响，特别是对于单尺寸颗粒的组装，薄球床会出现各向异性有效导热现象。在本文中，由直径为 1 mm 的薄陶瓷卵石床组成$升{\mathrm{一世}}_4秒\mathrm{一世}{哦}_4$粒子由 EDEM 2.7 生成。采用三维热网络法分析了不同厚度球床在三维方向上的有效导热系数。据观察，薄$升{\mathrm{一世}}_4秒\mathrm{一世}{哦}_4$球床在实际设计尺寸下显示各向异性有效热导率。通常，由于重力作用，沿床层垂直方向的有效热导率高于水平方向。随着厚度从 10 mm 增加到 40 mm，球床的有效导热系数逐渐增加。