Dr. Jason M. Harp
Group Leader and Senior Research Staff
Nuclear Fuel Element Performance Group
Nuclear Fuel Development Section
Oak Ridge National Laboratory

Abstract

Several efforts are underway at Oak Ridge National Laboratory to provide experimental results that support the extension of light water reactor fuel burnup beyond the current regulator limit of 62 MEd/kgU.  A pressing issue limiting burnup extension concerns the behavior of fuel during a Loss of Coolant Accident (LOCA). One phenomenon known as High Burnup Fuel Fragmentation (HBFF) and subsequent Fuel Fragmentation Relocation and Dispersal (FFRD) that may occur after fuel rod burst following LOCA are of particular concern for the US Nuclear Regulatory Commission and other worldwide regulators.  These events are investigated at ORNL through the use of a nationally unique experimental apparatus known as the Severe Accident Test Station (SATS) that enables the simulation of a LOCA on segments of irradiated nuclear fuel. Additionally, research into the microstructure of fuel that is susceptible to HBFF and the microstructural features that contribute to pulverization will be presented.  Recent insights from microstructural characterization of irradiated fuel at several different length scales help to reveal the driving mechanisms of HBFF.  New additions to SATS and new experimental devices also permit the investigation of transient Fission Gas Release (tFGR) during LOCA conditions.  Additional fission gas release during a LOCA even may increase the severity of burst behavior by enhancing cladding ballooning prior to burst. The new instrument and recent measurements of tFGR from high burnup light water reactor fuel will be presented.

Biography

Jason M. Harp Ph.D. is a senior staff scientist and group leader at Oak Ridge National Laboratory in the Nuclear Fuel Element Performance Group where he studies irradiation effects on nuclear fuel performance on a variety of different fuel types for different reactors. Specifically, he leads examination on fuel samples from the commercial Accident Tolerant Fuel (ATF) and LWR high burnup fuel and fuel samples from the MiniFuel irradiation vehicle, that allows for rapid screening and evaluation of novel fuel concepts. Previously he was staff at Idaho National Laboratory where he led studies of metallic, oxide and nitride fuel for advanced reactors and lead studies of various different enhanced accident tolerant fuels for LWRs all in the Advanced Fuels Campaign.  The fuel research for fast spectrum reactors focused on high burnup concepts and incorporating minor actinides into fuel.  The ATF irradiations focused on the feasibility of different fuel for deployment in LWRs to improved performance.  He was also involved in the post irradiation examination of the TRISO fuel, specifically working on the distribution of fission products in these experiments.  Additionally, he was involved with the fabrication of uranium silicide fuel at INL for accident tolerant fuel.  He is the author of over 20 first author publications. Dr. Harp holds a Ph.D. in Nuclear Engineering from North Carolina State University (2010), a M.S. in Nuclear Engineering (2008) from North Carolina State University and a B.S. in Nuclear Engineering from Texas A&M University (2005).

Thursday, October 26. 2023
4:00 pm seminar

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