29th Symposium of AER on VVER Reactor Physics and Reactor Safety (2019, Energoland, Mochovce NPP, Slovakia)
reactor dynamics and safety analysis
V.I. Romanenko, V.G. Zimin, S.P. Nikonov, G.V. Tikhomirov, Y. Perin, R. Henry, K. Velkov
Currently, due to the rapid pace of development of computer technology, the development of a multiphysics approach to modeling physical processes is becoming more widespread. Taking into account several physical phenomena and their influence on each other allows you to get more close to real results. Since feedbacks sometimes have a significant impact on the calculation results, the creation of coupled codes is an important component of the development of an approach to modeling physical processes in both nuclear reactors and other fields. In the field of modeling of the nuclear reactors, the consideration of feedbacks between thermal hydraulics and neutron physics is of the greatest importance. To simulate dynamic processes, as a rule, coupled solutions of fast diffusion neutron-physical codes and thermohydraulic sub-channel or best-estimate codes are used. In this paper, we consider the creation of a coupling scheme of the SKETCH-N nodal neutron-physical code and the best-estimate thermohydraulic code ATHLET. Various possible options for exchanging data between codes are considered, after which it was concluded that it is advisable to exchange data between codes by using computer memory (using the MPI library). Verification and validation were performed using the results of the Kalinin-3 international benchmark test. The calculation results and their comparison with experimental data and calculations using other codes show good convergence. During the creation of the coupling scheme, the creation of a system for processing and visualization of calculated data was also begun. Calculations of the stationary state were carried out using both simple (163 channels) and complex (simulation of the complete primary circuit) thermohydraulic models. The calculations of the dynamic shutdown of the MCP were carried out using a complex thermohydraulic model taking into account mass transfer between the channels.