Stress Profile in Coating Layers of TRISO Fuel Particles in Contact with One Another

Abstract

This work presents a discussion on a series of finite element analyses that assess stress evolution in the coating layers of tristructural isotropic (TRISO) particles in contact with each other while embedded in a matrix. The initial simulations were of applied uniaxial pressure versus matrix elastic modulus. These simulations predicted increasing stress in the silicon carbide coating layers of the TRISO particles with decreasing matrix elastic modulus. The second set of simulations focused on the effects of heating and cooling and the associated dimensional change on the state of stress in the coating layers. The general finding was that there was no significant difference below the coating layer’s deposition temperature. However, above the deposition temperature, the contacting particles had higher stress compared with those that were separated. The third set of simulations focused on the effects of irradiation, specifically, creep, dimensional change, and swelling. An interface debonding model was introduced since these potential effects have a significant bearing on predicted stresses.

Keywords:

• TRISO
• debonding
• contact
• BISON
• fracture

Acknowledgments

Tyler Gerczak, Nathan Capps, and Andrew Nelson provided valuable comments on the paper. The authors acknowledge the high-performance computing resources made available for this work at Idaho National Laboratory. This research was supported by the Transformational Challenge Reactor program, U.S. Department of Energy (DOE), Office of Nuclear Energy.

This manuscript has been authored by UT-Battelle, LLC under contract no. DE-AC05-00OR22725 with the DOE. The U.S. government retains and the publisher, by accepting the paper for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).

Disclosure Statement

No potential conflict of interest was reported by the authors.