Abstract:

The realization of advanced nuclear reactors requires the qualification of new fuel forms. The DOE Advanced Gas Reactor Fuel Qualification and Development (AGR) Program has undertaken an effort to qualify tristructural-isotropic (TRISO) coated particle fuel for high temperature gas reactors (HTGRs) absent a specific reactor design. The multidecade, applied program has re-established domestic coated particle fuel fabrication expertise and irradiation testing and post irradiation examination (PIE) capabilities. This overall effort has ultimately demonstrated excellent fuel performance, that is, retention of fission products over a broad range of irradiation conditions (temperature, fast fluence, burnup). The implementation of a novel multi-scale PIE approach has provided a mechanistic understanding of TRISO fuel performance to support the rigorous fuel qualification data packages. This mechanistic understanding of fuel performance provides opportunity to evolve the TRISO fuel design to improve performance for HTGRs and beyond. An overview of the TRISO fuel form will be presented along with the specific examples of PIE observations informing fuel performance such as integral SiC layer failure behavior and fission product transport. The research framework established for TRISO fuels has applicability across other fuel forms. Along with the TRISO focus a brief extension towards LWR UO₂ evolution including understand high burnup structure formation will be presented followed by a vision for new research topics and scientific goals using the methods and approaches presented.

Bio:

Dr. Gerczak joined the Nuclear Fuel Materials group at the Oak Ridge National Laboratory (ORNL) in November 2013. Prior to joining ORNL, Dr. Gerczak was a Research Assistant at the University of Wisconsin - Madison, where he earned a Doctorate of Philosophy in Materials Science in 2013. Dr. Gerczak’s primary research interests are focused on understanding nuclear fuel evolution and fission products transport. His work involves both tristructural-isotropic (TRISO) coated particle fuel and light water reactor fuel systems. His research centers on irradiation testing, post-irradiation examination characterization of irradiated fuel, and separate effects testing to isolate fuel performance variables and ultimately support model development and fuel qualification. Dr. Gerczak’s work is heavily focused in support of the Advanced Gas Reactor Fuel Qualification and Development program which aims to demonstrate the capability to produce high quality fuel for advanced reactor concepts. In this effort, an understanding of as-fabricated TRISO fuel and irradiated fuel performance over normal and off-normal conditions is generated.

Dr. Gerczak is active in organizing science outreach. He is the MeV School ORNL Academic Dean and has served as an organizer of the 2016 MeV School offering. He is also serving as the Scientific Program Chair for the biannual Workshop on High Temperature Gas-Cooled Reactor SiC Material Properties.