Angular flux discontinuity factors for reactor core transport calculation - 311

Assembly homogenization is needed to reduce computation time in neutron transport calculation of reactor core, specially, when strong neutron absorbers exist in the reactor core. This paper studies the homogenization of control assemblies with heterogeneously distributed absorbers in a research reactor core. We upgrade the two dimensional Sn code so as to have the function of calculating the angular discontinuity factors which can be used in other Sn code. This paper studies the Japanese Research Reactor, JRR3M, using the super cell model to calculate the angular discontinuity factors of the control rod assemblies (iterative method), and then calculates the core parameters with them. The study shows that the Keff of the homogenized transport calculation of reactor core with angular discontinuity factors is approximately the same as that of the heterogeneous Sn calculation. This paper indicates the necessity of using the angular discontinuity factors in the transport calculation. (authors)