RESEARCH ON IMPROVEMENT OF HTGR CORE POWER-DENSITY:

(2) ASSESSMENT OF SIC OXIDATION BEHAVIOR UNDER HTGR AIR INGRESS ACCIDENT

Abstract

Recently, we have been proposing a sleeveless SiC matrix fuel compact design to increase the core power density and enhance the safety for High Temperature Gas-cooled Reactor (HTGR). For that application, the oxidation behavior of Reaction-Sintered Silicon Carbide (RS-SiC) under conditions of air ingress accident needs to be investigated. However, few study focused on RS-SiC oxidation, especially under conditions of interest for HTGR. The detailed RS-SiC oxidation kinetics and passive-to-active transition behavior remain unclear. In this work, aiming at feasibility of sleeveless SiC matrix fuel compact for HTGR application, thermogravimetry (TG) measurements were carried out in the conditions of 800 ~ 1400 ℃ and 1 ppm ~ 20 % oxygen concentration under atmospheric pressure, 30 min real-time monitoring. As a result, we have experimentally determined the passive-to-active transition that might be encountered in case of accidents. The present study successfully collected basic data on RS-SiC oxidation, thus, the material feasibility of sleeveless SiC matrix fuel compact for HTGR use was obtained. We partly concluded that the RS-SiC can be applied to HTGR fuel matrix material in the case of air ingress accident.