Heterogeneous reactor core transport technique using response matrix and collision probability methods

Highlights: • A computer program HERPAT, Heterogeneous Reactor Particle Transport, is developed. • DP₂ Legendre polynomial is used to approximate the surface angular flux. • The integrals are evaluated using macro-band and Carlvik’s method. • The proposed method has a desired performance and guarantees acceptable results. • Efficiency measures the ability to minimize computer execution time and storage requirements. - Abstract: In this paper a whole-core transport technique using response matrix and collision probability (CP) methods is presented for large-scale, highly-heterogeneous reactors. Integral transport method has been used to provide sufficient accuracy for response matrix formation of pin cell sized node with considerably less computational expense. Ray tracing is efficiently applied using macro-bands. For practical application, double P₂ (DP₂) Legendre polynomial expansion is applied to approximate interface angular flux that is used to couple nodes. The proposed method is based on a sound mathematical foundation and leads to dramatically reduced memory requirements in contrast to the conventional transport method. This method is also applied to several problems such as C5G7, containing mixed oxide (MOX) and UO₂ fuel assemblies, to show the effectiveness of the proposed method. The results clearly indicate that the method is quite promising and acceptable