Abstract:
Analyzing and modeling a core with transport high-fidelity pin-by-pin calculation is becoming relevant since it provides insight into reducing the safety conservatism for design basis accidents, increasing the overall economics of the nuclear power plants. Currently, several methodologies provide an excel-lent approximation to the Neutron Transport Equation, each with associated strengths and weakness-es. Of all these, some of the most widely accepted and well-established methodologies are the spher-ical harmonics method (PN), discrete-ordinates method (SN), method of characteristics (MOC), and Monte Carlo (MC). At KIT-INR, there is an effort to develop in-house tools for analyzing Small Modular Reactors (SMRs) pin-by-pin with transport instead of using diffusion or SP3 approximations. Hence the PARAFISH code has been developed.
The PARAFISH code is a deterministic neutron transport solver based on even parity formulation de-veloped by the KIT. The code solves the 2D/3D (cartesian geometry) steady-state neutron transport equation for multiplicative media. Discretization is performed using the multi-group approximation for the energy variable, non-conforming finite elements for the spatial variable, and spherical harmonics expansions (PN method) for the angular variable.
The OECD/NEA C5G7 MOX Benchmark was used to verify and validate the tool since it is one the most widely numerical exercise for neutron transport. Moreover, the benchmark is suitable for testing the ability of modern transport codes to treat LWR cores without spatial homogenization. The results obtained are concordant with the reference showing that increasing the spatial-angular resolution re-sults are in better agreement, but the computational time increases considerably. Finally, these results demonstrate PARAFISH's capability to simulate a core pin-by-pin with acceptable accuracy.