Steady and transient solutions of neutronics problems based on finite volume method (FVM) with a CFD code

In recent years, Computational Fluid Dynamics (CFD) methodology has been widely used for solving multi-dimensional thermal-hydraulics problems in nuclear science and engineering. As for the neutronics analysis, it mostly depends on the deterministic or probabilistic method codes which are independent of the thermal-hydraulic ones. Usually an extra interface program needs to be developed for the data exchange between the two kinds of codes in the coupled calculation. In this paper, a Temporal And Spatial Neutronics Analysis Module (TASNAM) in commercial CFD package FLUENT was developed based on the User Defined Function (UDF) and User Define Scalar (UDS) to solve the neutronics problems. Neutron diffusion equations and delayed neutron precursors balance equations are discretized by finite volume method (FVM) and can be solved with CFD conservation equations simultaneously. In order to demonstrate the feasibility and accuracy of TASNAM in FLUENT, three neutronics benchmark problems, the 2D-IAEA, 2D-TWIGL, and 2D-LRA benchmark problem are analyzed. The calculation results in the present paper have a good agreement with the reference values, which demonstrates that the TASNAM in FLUENT can solve neutronics problems accurately.