[2E14-18] High-temperature Gas-cooled Reactor, Fundamental Property

[2E14] Multiphysics Behavior in HTGRs with High Power Density

(1)Accident Behaviors of Fuel Matrices

*Yosuke Nishimura¹, Anna Gubarevich², Katsumi Yoshida², Kuniyoshi Takamatsu³, Koji Okamoto¹ (1. The University of Tokyo, 2. Tokyo Institute of Technology , 3. Japan Atomic Energy Agency)

Keywords:Fuel safety, High-temperature gas-cooled reactors, Silicon carbide, Reaction sintering, Air ingress accident

In the development of innovative fuel for high-temperature gas reactors positioned as next-generation reactors, using SiC matrix aims to increase the core output density and enhance safety during accidents. This study measured the thermal and chemical properties of high-density SiC matrix fabricated preliminarily using a reaction sintering method. The crucial property of thermal conductivity, significant for reactor materials, demonstrated values ensuring that the fuel's maximum temperature remains below the allowable limit during normal operation of the high-temperature gas reactor. Additionally, SEM and XRD analyses confirmed the presence of residual unreacted C and Si in the SiC matrix. The impact of approximately 10 wt.% residual Si on the high-temperature oxidation behavior of fuel during air ingress accidents, a representative accident scenario, was experimentally investigated.