Transient coupling analysis of loss-of-coolant accidents in HTR-PM based on CFD approaches

Abstract

Pressurized loss of forced cooling (PLOFC) and depressurized loss of forced cooling (DLOFC) are two important accidents in high temperature gas-cooled reactors. In the present study, it is intended to investigate thermal–hydraulic behaviors of the reactor core under these two accidents using the CFD approach. To this end, a coupling solver is developed based on the OpenFOAM platform. The computational domain is a 12° wedge-shaped three-dimensional region for the core of HTR-PM. The performed analyses demonstrate that the maximum relative error is less than 3.9%, indicating the accuracy and reliability of the established model. Moreover, it is found that there exists a short period when the heat is transferred from the coolant helium to the pebble-bed during the initial stage of PLOFC case. The maximal fuel temperature of 1195 ℃ occurs at t = 15.3 h for PLOFC, and the maximal fuel temperature of DLOFC is 1449 ℃ at t = 26 h. The obtained results reveal that sufficient safety margin is ensured under the PLOFC and DLOFC accident scenario.