Date of Award
Master of Science
Stephanie TerMaath PhD
Reza Abedi PhD, Tyler Gerczak PhD
The Advanced Gas Reactor Fuel Development and Qualification program is an ongoing effort to build a database on coated particle fuel for the future licensing and qualification of tristructural-isotropic (TRISO) coated particle fuel production in the United States. Several irradiation experiments have been produced throughout the program, were subjected to irradiation testing, and are currently in the process of post-irradiation examination (PIE). During this examination process it has been found that the first two irradiation experiments displayed varying fracture characteristics of primarily the buffer layer that would affect a particle’s ability to retain fission products. This disparity in fracture characteristics is believed to originate from a variation in properties in the particle coatings between the two irradiation experiments. A host of methods for characterizing the primary coating of concern, the buffer, are investigated and ultimately three methods were chosen for testing. Nanoindentation, micro-cantilever testing, and image analysis methods were utilized on particles from both irradiation experiments to identify any variations that may exist between them. Based on the data from nanoindentation and image analysis, differences in both hardness and porosity exist between both irradiation experiments and logically align with why one group of fuel performed differently than the other. The work involving micro-cantilever testing also showed a variation in properties between irradiation experiments that are consistent with why IPyC fractures were more prevalent in AGR-1 but requires more thought in refining the process for more consistent results. The end goal for this work would be to implement a quality control check for testing particle buffer coatings using the methods chosen, but more refining of the methods and testing will be required.
Schumacher, Austin, "Characterizing and Comparing Tristructural-Isotropic Buffer Properties from AGR-1 and AGR-2 Irradiation Experiments. " Master's Thesis, University of Tennessee, 2019.