球床型氟盐冷却高温堆的初步中子学分析

为分析球床型氟盐冷却高温堆（PB-FHR）堆芯的关键中子学参数，建立了显式随机模型，基于随机填充方法计算了燃料球石墨基质内所有三层各向同性包覆颗粒（TRISO）颗粒的空间坐标，并采用离散元方法计算出堆芯活性区内全部燃料球的空间坐标。最后采用蒙特卡罗程序开展中子输运计算，分析燃料颗粒随机分布对堆芯中子学参数的影响。研究结果表明，TRISO颗粒的随机分布对栅元增殖系数、栅元群截面、活性区燃料球功率的影响较小，本文研究可为简化PB-FHR设计提供理论依据。 

Preliminary Neutronics Analysis for Fluorine-Salt-Cooled Pebble-Bed Reactor

In order to obtain the key neutronics parameters of the pebble-bed fluoride-salt-cooled high-temperature reactor(PB-FHR), the random packing method is used to obtain the coordinates of the three layers of isotropic coated particles(TRISO) particles, and the discrete element method is adopted to the coordinates of the fuel pebbles within the active core. Then the neutron transport calculated is conducted by the Monte Carlo code to analyze the effects of the fuel random distribution on the core neutronics parameters. The calculation results showed that the effects of the random distribution on the multiplication coefficient, group cross section and active core fuel pebble power can be neglected. Based on the above results, the nuclear design of the pebble-bed fluoride-salt-cooled high-temperature reactor can be simplified.