Development of a One-Dimensional Thermal-Hydraulics Model Intended for Studying Stability of a Reactor with a Supercritical Steam Coolant

Abstract

This article presents the results of the development of one-dimensional thermal-hydraulics model of the reactor core with a supercritical steam coolant (SCPS-600 type), intended for the analysis of thermal-hydraulic stability. To create it, an approach was chosen that involves the use of a modified semi-implicit algorithm based on SIMPLE. The algorithm was implemented using C ++ software. The object of the study was a single channel with a circular cross-section with the fuel assemblies of a hexagonal shape in it. A calculation was carried out that simulates the process of starting the reactor and its reaching the steady state mode. The calculation was carried out in two stages: at the first stage, the ascending flow was established in the unheated channel; at the moment of time 0.2 s, the heating of the system began, which led to a rearrangement of the velocity, pressure and temperature fields. The model included the conservation of momentum, and the energy of the coolant in the core, presented as finite differences. All the properties of the supercritical steam coolant required for the calculation were obtained using the IAPWS-IF97 library. The algorithm assumes solution of the basic equations of thermal-hydraulics with continuity check twice at one time step. Based on the results of the calculation, a picture of the fields of velocity, pressure and temperature was obtained. With the help of the heat balance, a conclusion was made about the correct operation of the model and the possibility of its application for the analysis of the stability of a reactor with a supercritical steam coolant.