MODELING OF THERMOHYDRAULIC PROCESES IN ROD TIPE FUEL ASSEMBLIES OF WATER COOLED REACTORS
24th Symposium of AER on VVER Reactor Physics and Reactor Safety (2014, Sochi, Russia)
Nuclear applications of computational fluid dynamics (CFD)
Abstract
MODELING OF THERMOHYDRODYNAMIC PROCESSES IN FUEL ROD ASSEMBLIES OF WATER COOLED REACTORS
Semenovich O.V.
JIPNR‒Sosny of NAS of Belarus, Minsk, Belarus
ABSTRACT
The report discusses the results of computer simulation of thermohydrodynamic processes in the fuel rod assemblies of water cooled reactors.
The coolant in pressurized water reactors during normal modes is a single phase liquid. In emergencies the coolant boils, turning into a vapor-liquid mixture. In the coolant implemented various modes of flow and heat transfer. Correctly describe such processes can only simulating vapor-liquid mixture in the approximation of a separate phase flow.
To perform these investigations used software package that implements the three-fluid three-field subchannel mathematical model. Such a model is suitable for studying the processes of thermohydrodynamic in fuel assemblies in all possible modes of operation. Considered in detail the mathematical model and its discrete analogue. For the numerical implementation used the semi-implicit numerical scheme. All variables that are present in the source terms and the terms describing the interaction at the interfaces and surfaces of solid walls are treated in an implicit interpretation: estimated values inherent in the new (n+1) point in time. Also interpreted the phase velocities included in the convective terms of mass and energy, and pressure. Members of the convective flux of mass, momentum, energy, evaluated at the old (n) time step: explicitly. The “chess” grid is used for discretization in the spatial variable. A model of thermomechanical processes in rod fuel element that used in the subchannel code is considered.
The report analyzes the results of computer simulation