Research on on-the-fly doppler broadening based on modified Gauss-Hermite method

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. (authors)