Dr. Jim E. Morel
Department of Nuclear Engineering
Texas A&M University

Abstract

Computing Sn solutions for a distributed isotropic point source is extremely difficult due to ray effects.  Most Sn codes decompose the solution into an uncollided component and a collided component with the uncollided component done with ray-tracing of some sort and the collided component done with Sn.  Ray tracing has inherent difficulties. For instance, with a uniform set of rays, the distance between rays increases with distance from the source requiring some sort of angular refinement to pass rays through each spatial cell; and local conservation is difficult to achieved.  We have derived an advection-removal equation for the scalar flux from a point source that can be discretized and solved using Sn methods.  A single “sweep’’ through the mesh for a single scalar flux unknown per group yields the complete solution including any anisotropic moments for the first-scattered distributed source.  We derive this equation and present computational results in both a simplified 2-D flatland context as well as 3-D calculations with an unstructured mesh.

Biography

Professor Jim E. Morel received a B.S. in mathematics from Louisiana State University in 1972, an M.S. in nuclear engineering from Louisiana State University in 1974, and a Ph.D. in nuclear engineering from the University of New Mexico in 1979. He began his career in 1974 as a nuclear research officer at the Air Force Weapons Laboratory. In 1976 he became a staff scientist at Sandia National Laboratories. In 1984 he became a staff member at Los Alamos National Laboratory, eventually serving as a group leader and scientific advisor. In 2005 he accepted a professorship in the Department of Nuclear Engineering at Texas A&M University (https://engineering.tamu.edu/nuclear/). In 2007 he became Director of the Center for Large Scale Scientific Simulations at TAMU (https://class.tamu.edu). In 2020 he became the Co-Director of the Joint Center for Resilient National Security, a joint center of Los Alamos National Laboratory and the Texas A&M System (https://nationallabsoffice.tamus.edu/jcrns/ ). He has published 128 journal articles, 90 refereed full conference papers, and 27 refereed conference summaries relating to numerical methods for neutral particle transport, charged-particle transport, thermal radiation transport, and radiation-hydrodynamics.

Thursday, April 17. 2025
4:10 pm seminar

zoom link upon request