Dr. David L. Luxat
Manager
Severe Accident Modeling & Analysis
Sandia National Laboratories

Abstract

MELCOR is an integrated severe accident code used for source term analysis that has been developed at Sandia National Laboratories (SNL) for the United States Nuclear Regulatory Commission (USNRC) since the early 1980s. MELCOR originated to characterize plant behavior under accident conditions for Light Water Reactors (LWRs). Continuous development has advanced its application to non-LWR concepts. Modeling for thermal hydraulics, neutronic response, core heat-up, core degradation, radionuclide release and transport, and ex-vessel/containment phenomena (molten core-concrete interactions, melt spreading, sodium fires, etc.) have been developed for application to LWRs, Spent Fuel Pools (SFPs), High-Temperature Gas-cooled Reactors (HTGRs), Heat Pipe Reactors (HPRs), Sodium-cooled Fast Reactors (SFRs), Fluoride salt-cooled High-temperature Reactors (FHRs) and liquid-fueled Molten Salt Reactors (MSRs). Recent model advancements for non-LWR applications have generalized the treatment of the Equation of State (EOS) for non-LWR coolants, enabled treatment of fission product diffusion and release in TRISO particles, fission product release for metallic fuels, fission product retention in molten salt and sodium coolants, sodium fire models, heat pipe models, and neutronic response of solid- and liquid-fueled systems. These new non-LWR models have been successfully exercised in demonstration calculations for the United States NRC. This talk discusses the objectives of MELCOR code modelling enhancements across reactor technologies, recently added physics and chemistry modelling capabilities targeted to advanced nuclear energy technologies and presents examples of preliminary demonstration non-LWR analyses.

Biography

David L. Luxat received his Ph.D. In theoretical condensed matter physics from the University of Toronto prior to entering the nuclear industry. He has led a range of initiatives in both the U.S. and Canadian nuclear industries to enhance, through modeling and simulation, the characterization of both safety margin and risk for a range of nuclear energy technologies. Prior to joining Sandia National Laboratories in 2019, David and his team at Jensen Hughes (formerly ERIN Engineering) led a number of initiatives in the United States nuclear industry following the core melt events at Fukushima Daiichi. These included the EPRI forensic evaluation of the Fukushima Daiichi events, enhancement of EPRI’s severe accident management guidance technical basis, the industry methodology to resolve issues under the NRC Containment Protection and Release Reduction (CPRR) rulemaking, evaluation of safety benefits arising from Accident Tolerant Fuel (ATF), and enhancement of EPRI’s Modular Accident Analysis Program (MAAP) to account for thermal stratification and core degradation insights from Fukushima Daiichi. David currently leads nuclear energy safety studies at Sandia National Laboratories as the manager of the Severe Accident Modeling/Analysis department, which is responsible for development of the MELCOR computer code for the NRC.

Thursday, November 2. 2023
4:00 pm seminar

zoom link upon request

BU 1202