氟盐冷却球床堆球栅元少群截面计算

Generation of Few-group Cross Sections for Pebble-bed Fluoride-salt-cooled High-temperature Reactors

氟盐冷却球床堆经10余年的发展,已逐步由预概念设计走向试验堆基准设计。本文采用确定论软件中的碰撞概率法模块对氟盐冷却球床堆球栅元建模,计算了其无穷增殖因数,少群均匀化总截面、俘获截面和裂变截面,并使用连续能量蒙特卡罗软件验证与分析。其中使用基于碰撞概率法的共振处理程序直接求解共振能区超精细群慢化方程,很好地处理了氟盐冷却球床堆的球型燃料元件所构成的双重非均匀系统。结果表明:确定论软件中碰撞概率法模块的计算结果与蒙特卡罗软件结果吻合,适用于对氟盐冷却球床堆进行少群截面加工。

Pebble-bed fluoride-salt-cooled high-temperature reactors （PB-FHR） have made progress to the stage of baseline designing of test reactor after more than ten-year pre-conceptual designing. Collision probability method was applied to solve the neutronic system of one pebble of PB-FHR, and attained its infinite multiplication factor and cell-homogenized few-group cross sections including total, capture and fission cross sections. The evaluation of accuracy of the output was based on comparison to a continuous-energy, doubly heterogeneous Monte Carlo reference model. Resonance calculation routine solved slowing-down equations on the ultra-fine lethargy mesh by collision probability method, through which the doubly heterogeneous system could be treated accurately. Results show that outputs from collision probability method are consistent with that of Monte Carlo reference model, and collision probability lattice code with ultra-fine resonance calculation is capable of generating few-group cross sections for PB-FHR.