A summary is described about nuclear power reactors analyses and simulations in the last decades with emphasis in recent developments for full 3D reactor core simulations using highly advanced computing techniques. The development of the computer code AZKIND is presented as a practical exercise. AZKIND is based on multi-group time dependent neutron diffusion theory. A space discretization is applied using the nodal finite element method RTN-0; for time discretization the ?-method is used. A high-performance computing (HPC) methodology was implemented to solve the linear algebraic system. The numerical solution of large matrix-vector systems for full 3D reactor cores is achieved with acceleration tools from the open-source PARALUTION library. This acceleration consists of threading thousands of arithmetic operations into GPUs. The acceleration is demonstrated for different nuclear fuel arrays giving extremely large matrices. To consider the thermal-hydraulic (TH) feedback, several strategies are nowadays implemented and under development. In AZKIND, a simplified coupling between the neutron kinetics (NK) model and TH model is implemented for reactor core simulations, for which the TH variables are used to update nuclear data (cross sections). Test cases have been documented in the literature and demonstrate the HPC capabilities in the field of nuclear reactors analysis.
Part of the book: New Trends in Nuclear Science