Numerical approach for estimating the conditions for natural circulation in a simple nuclear passive system

Abstract

The design and deployment of integrated modular water reactors (IMRs) and evolutionary reactors whose operations are based on passive systems are on the rise. The natural circulation (NC) based passive systems being adopted rely on natural convection, buoyancy driven-flow and vapour condensation. In this work, a numerical approach that can determine the required conditions for establishing this widely applied thermal hydraulic phenomenon in simple turbulent two phase nuclear passive system is presented. Through the method, other relevant thermal-hydraulic parameters which are of interest in safety and reliability analyses of such NC-based systems can also be obtained. The case of the System-integrated Modular Advanced ReacTor (SMART) based on the method was demonstrated. Furthermore, the validity of the approach was proven using the test data and simulation results of a NC-based experimental facility. The method is simple and easy to apply to NC-based systems of similar configurations. (C) 2020 Elsevier Ltd. All rights reserved.