Abstract
The majority of this paper investigates thermal-hydraulic characteristics in a high-temperature gas-cooled reactor (HTGR) core under steady-state and accident conditions through a transient three-dimensional compressible CFD model. With the pebble-bed geometry, the HTR-10 core is selected for the present simulations. A loss-of-coolant accident (LOCA) with double-ended rupture of a gas duct tube is assumed and the core power would decay following this accident. In this LOCA, air in the steam generator cavity would enter the core via diffusion and natural convection mechanisms. Following air ingress into the core, O 2 would react with graphite on pebble surface, causing the generation of CO 2 and CO. The main thermal-hydraulic characteristics during this air ingress accident include O 2 ingress into the core, CO 2 and CO production histories, He concentration variations, and coolant temperature transient behavior, etc. Based on the present simulation results, the peak coolant temperature during the air ingress accident is slightly higher than that under the steady-state condition, revealing the safety of HTR-10 core in this postulated accident from the thermal point of view. In addition, corrosion phenomena related to the fuel pebbles are discussed and presented in the next paper. © 2011 Elsevier B.V. All rights reserved.