Traditional reactor system analysis tools are confronted with challenging difficulties in model development, low accuracy, and poor convergence. To solve these problems, the automatic differentiation (AD) method that allows the automatic numerical calculation of derivatives of functions was adopted to develop the reactor system code in this paper. For the simulation of single-phase models, the steady and transient responses were presented to investigate the effects of the spatial and temporal discretization schemes on modeling accuracy and efficiency. Meanwhile, the comparison of convergence performance between the automatic differentiation using operator overloading (ADOO) and the traditional hand-coded method was completed. Further, in the case of two-phase flow problems, the high-order discrete schemes were applied in this code. It was demonstrated that the reactor system code with single-phase and five-equation two-phase flow models, which adopted the high-order discretization and the ADOO method, performed very well for one-dimensional flow and heat transfer problems.

传统的反应堆系统分析工具在模型开发，准确性低和收敛性方面面临挑战。为了解决这些问题，本文采用允许函数导数自动数值计算的自动微分（AD）方法来开发反应堆系统代码。对于单相模型的仿真，提出了稳态和瞬态响应，以研究时空离散方案对建模精度和效率的影响。同时，完成了使用算符重载（ADOO）的自动微分与传统的手工编码方法之间的收敛性能的比较。此外，在两相流问题的情况下，在此代码中应用了高阶离散方案。