基于改进Gauss-Hermite方法的在线多普勒展宽方法研究

Research on On-the-fly Doppler Broadening Based on Modified Gauss-Hermite Method

温度对核截面的效应对反应堆中子学计算有重要影响,同时也是热工反馈的基础。准确、高效且内存占用较少的蒙特卡罗截面在线温度处理方法是其中的关键。基于多普勒展宽理论及Gauss-Hermite求积组,可使用基准温度下的截面对任意温度进行展宽计算,实现蒙特卡罗粒子输运过程中的在线多普勒展宽。本文针对传统Gauss-Hermite方法存在的问题,对该方法进行了改进,并利用典型压水堆算例进行了验证分析。结果证明,改进算法显著地提高了效率,为在线多普勒展宽方法在多物理耦合中的应用提供了基础。

Effects of the temperature on the nuclear cross sections are significant in reactor neutronics calculations,and serve the foundation to thermal-hydraulics feedback.The accurate,high-efficient and memory-saving on-the-fly cross section treatment is the key factor.Based on the Doppler broadening theory and Gauss-Hermite quadrature,the cross sections at arbitrary temperature can be Doppler broadened using the cross sections at basic temperature,so as to achieve the on-the-fly Doppler broadening during the Monte Carlo particle transport simulations.The traditional Gauss-Hermite method by solving its problems was modified in this paper,and the proposed method was tested and analyzed using the typical pressurized water reactor cases.The results show that the proposed method can improve the efficiency effectively,which provides the foundation to the application of on-the-fly Doppler broadening in multi-physics coupling.