David Sulfredge is a Distinguished R&D staff member and group leader for the Multiphysics Modeling and Flows Group at ORNL, where he works on facility vulnerability and various types of thermo-fluid modeling. He has developed numerous nuclear facility models together with event/fault tree algorithms for estimating downtime and calculating the probability of facility kill or radiological releases. Many of these models have been incorporated into the Visual Interactive Site Analysis Code (VISAC) for assessment of nuclear facility vulnerability. His work also has included the design of scaled experiments to measure the blast fragility of nuclear power plant equipment and calculations with weapons effects codes. In addition to his explosives-related research, he has worked on thermal hydraulic design for the Advanced Neutron Source Reactor and Spallation Neutron Source projects, performed safety analysis for the High Flux Isotope Reactor at ORNL, and assisted in decommissioning of the Molten Salt Reactor Experiment. In recent years, he has performed extensive fluid flow analysis of the hydraulic behavior and separative performance in gas centrifuges, as well as heat transfer calculations to determine the temperature profile inside an operating centrifuge. David Sulfredge has written or contributed to over 75 published papers, research reports, conference proceedings and book chapters. He received his B.S., M.S., and Ph.D. degrees in mechanical engineering from the University of Kentucky.