三维离散纵标中子输运稳态及瞬态动力学计算

基于著名输运程序DOT4．2，开发了三维离散纵标中子输运稳态及瞬态动力学计算程序．对时间变量采用直接的无条件稳定且具有高精度的全隐式向后差分格式进行离散处理，将瞬态输运方程转化为各个离散时间步上的固定源型稳态中子输运方程进行求解．通过对TAKEDA基准题及输运瞬态基准题的校验计算表明：该三维稳态程序能准确地给出有效增殖系数以及各区的区域平均中子通量密度，其相对误差分别小于0．1％和4．0%；对于缓发超临界和瞬发超临界问题，三维瞬态程序的计算结果均与参考值吻合良好．本三维程序可以为复杂反应堆堆芯的临界计算和瞬态动力学特性分析提供一个有效而准确的分析工具和手段．

Discrete Ordinates Solutions of Three-Dimensional Steady and Transient Neutron Transport Equations

Steady and a transient discrete ordinates neutron transport codes for three-dimensional geometry were developed based on the program DOT4. 2. For the implementation of the time-dependence, a direct method, the fully implicit and unconditionally stable time integration scheme, was employed. The transient neutron transport equation was turned into the fixed-source neutron transport problem, and solved by the steady transport code for each time step. The two codes were tested with the TAKEDA benchmark and several transient benchmark problems. The numerical results show that the effective multiplication factors and regionwise neutron fluxes can be predicted accurately by the three-dimensional steady code with errors less than 0.1% and 4.0% respectively, for both delayed and prompt supercritical problems, the obtained results agree very well with the benchmark problem ones.