基于不连续因子的沸水堆芯三维瞬态数值模拟

基于不连续因子校正的粗网格有限差分法是实现堆芯瞬态三维数值模拟的高效方法之一, 粗网节块的界面不连续因子与边界反照率的计算方法决定了实时数值模拟过程中的精度。在计算不连续因子的过程中, 省去了细网节块计算与粗网均匀化过程, 直接在粗网格划分情况下, 基于节块展开法和非线性迭代策略, 推导了粗网格界面不连续因子比率与边界反照率的计算公式, 并编制了相应的计算程序。沸水堆典型算例的三维瞬态模拟证实该方法可在空间域和时间域两方面, 使静态、瞬态精度均达到与先进节块法相等同的程度, 并且计算效率优于先进节块法, 为核电站全范围模拟机三维堆芯的实时仿真模型开发提供了一种切实可行的选择。

Three-dimensional boiling water reactor core transient simulation based on discontinuity factor

The coarse mesh finite difference method with discontinuity factor correction is one of the effective methods to realize the core transient three-dimensional numerical simulation.The calculation method of coarse mesh interface discontinuity factor and the boundary albedo determines the precision in the process of real-time simulation.In the process of calculation of discontinuity factor and boundary albedo, the fine cell calculation and coarse mesh homogenization process is eliminated.Directly under the condition of the coarse cell, based on the nodal expansion method and nonlinear iterative strategy, coarse cell interface discontinuity factor ratio and boundary albedo are deduced.The corresponding calculation programs are developed.From a typical boiling water reactor 3Dtransient simulation benchmark, the method is proven to be available.The static and transient precisions both in space domain and time domain, are equivalent with that of the advanced nodal method, and the computational efficiency is superior to that of the advanced nodal method.This method provides a feasible choice for the development of full scope simulator of transient calculation of three-dimensional core model.