Session: 04-12: SMRs, Advanced Reactors and Fusion

Paper Number: 135182

135182 - V&v of Accident Behaviors in Silicon Carbide Fuel Matrices for High-Temperature Gas-Cooled Reactors 

Abstract: 

A novel approach to addressing challenges in high-temperature gas-cooled reactors (HTGRs) involves implementing a direct cooling method between a sleeveless fuel compact and the helium coolant within the core. A critical concern arises during Depressurized-Loss-Of-Forced-Coolant (DLOFC) accidents, wherein the potential for severe fuel oxidation at elevated temperatures poses a significant threat. The key to mitigating unacceptable fuel degradation and reducing the risk of radioactive releases lies in enhancing the fuel matrix's resistance to oxidation. While assessing reactor safety, it is imperative to conduct a Verification and Validation (V&V) study on fuel oxidation behavior. Unfortunately, both experiments and modeling in this regard are not fully developed, leading to a limited understanding of fuel oxidation during postulated accidental scenarios. This study addresses this knowledge gap by specifically investigating the oxidation behavior of silicon carbide, a promising candidate for the fuel matrix, in air up to 1400 ℃. Preliminary experiments informed the development of an empirical model for SiC oxidation kinetics. To further validate fuel safety assessment during HTGR accidents, comprehensive tests were conducted using the real-sized High Temperature Test Facility (HTTF) at The University of Tokyo. The upcoming conference will feature a presentation on the detailed experimental results, the proposed model, and a discussion on Verification and Validation. A novel approach to addressing challenges in high-temperature gas-cooled reactors (HTGRs) involves implementing a direct cooling method between a sleeveless fuel compact and the helium coolant within the core. A critical concern arises during Depressurized-Loss-Of-Forced-Coolant (DLOFC) accidents, wherein the potential for severe fuel oxidation at elevated temperatures poses a significant threat. The key to mitigating unacceptable fuel degradation and reducing the risk of radioactive releases lies in enhancing the fuel matrix's resistance to oxidation. While assessing reactor safety, it is imperative to conduct a Verification and Validation (V&V) study on fuel oxidation behavior. Unfortunately, both experiments and modeling in this regard are not fully developed, leading to a limited understanding of fuel oxidation during postulated accidental scenarios. This study addresses this knowledge gap by specifically investigating the oxidation behavior of silicon carbide, a promising candidate for the fuel matrix, in air up to 1400 ℃. Preliminary experiments informed the development of an empirical model for SiC oxidation kinetics. To further validate fuel safety assessment during HTGR accidents, comprehensive tests were conducted using the real-sized High Temperature Test Facility (HTTF) at The University of Tokyo. The upcoming conference will feature a presentation on the detailed experimental results, the proposed model, and a discussion on Verification and Validation.

Presenting Author: Yosuke Nishimura The University of Tokyo

Presenting Author Biography: Currently, Y. Nishimura is a PhD candidate at The University of Tokyo. He is major in nuclear materials and science. He has been working on a project to enhance thermal efficiency and safety for innovative design of high-temperature gas-cooled reactors (HTGRs).

Authors:

Yosuke Nishimura The University of Tokyo
Avadhesh Sharma The University of Tokyo
Anna Gubarevich Tokyo Institute of Technology
Katsumi Yoshida Tokyo Institute of Technology
Koji Okamoto The University of Tokyo