Development of Thermalhydraulic Modelling and Simulation Capabilities in CNL in Support of Advanced Reactors

Abstract

Within Canada, several advanced reactor concepts are undergoing vendor design review or site license application with the Canadian Nuclear Safety Commission (CNSC). Canadian Nuclear Laboratories (CNL) is a major hub of R&D that supports the CNSC, SMR stakeholders, industry, and academia. CNL is developing a unique multiphysics modelling code suite to support lab-scale experimentation and assess reactor safety under normal conditions and during accident transient events. This paper showcases ongoing efforts at CNL towards the development of standalone and coupled thermalhydraulics modelling capabilities to simulate postulated scenarios of relevance to gas-cooled advanced reactors. The main focus of this study is to showcase the participation of CNL in the application of standalone CFD for modelling the mixing in the lower plenum of the Oregon State University High Temperature Test Facility, within the HTGR T/H benchmark organized by OECD/NEA. The CFD results for the lower plenum mixing (problem #1 of the benchmark) using fixed boundary condition (Exercise #1), and the progress made in the coupling of Siemens STAR-CCM+ and the CNL system thermalhydraulics code ARIANT are discussed. Based on the significant progress achieved to date, CNL is well positioned to contribute to the next-phase Exercise #2 within the OECD/NEA HTGR T/H international benchmark on the modelling of lower plenum mixing.