Complex modeling of VVER-1000 fuel assembly using codes MCU/ATHLET with different hydraulic models

28th Symposium of AER on VVER Reactor Physics and Reactor Safety (2018, Olomouc, Czechia)
[1] Advances in spectral and core calculation methods


V. I. Romanenko, S. P. Nikonov, G. V. Tikhomirov (MEPhI)


Nowadays, due to the growth of computing power and the possibility of parallel computations, there is a tendency to more and more accurate and complete modeling of physical processes. However, many nuclear reactor design calculation programs and models embedded in them do not take into account the exchange between the elementary cells of the reactor. This can greatly affect the results of calculations, especially on the distribution of temperatures and densities of the moderator. In this paper, the results of the coupled thermal-hydraulic and neutron-physical pin-by-pin simulation of the VVER-1000 reactor fuel assembly 1 obtained using the precision neutron-physical code MCU (Monte-Carlo Universal) 2 and best estimate thermal-hydraulic code ATHLET (Analysis of Thermal-hydraulics of Leaks and Transients) 3 with different hydraulic exchange models between elementary cells in this fuel assembly.
This work is a continuation of the previous calculations presented in 4. The aim of this work is to determine the importance of taking into account turbulent and convective exchange between the cells of pins in the fuel assembly. For the calculations, high-precision thermo-hydraulic and neutron-physical codes were used with auxiliary programs written in Python 3 and allowing data transfer between input and output code files without changing the structure of the codes themselves.