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Remembering ANS member Gil Brown
Brown
The nuclear community is mourning the loss of Gilbert Brown, who passed away on July 11 at the age of 77 following a battle with cancer.
Brown, an American Nuclear Society Fellow and an ANS member for nearly 50 years, joined the faculty at Lowell Technological Institute—now the University of Massachusetts–Lowell—in 1973 and remained there for the rest of his career. He eventually became director of the UMass Lowell nuclear engineering program. After his retirement, he remained an emeritus professor at the university.
Sukesh Aghara, chair of the Nuclear Engineering Department Heads Organization, noted in an email to NEDHO members and others that “Gil was a relentless advocate for nuclear energy and a deeply respected member of our professional community. He was also a kind and generous friend—and one of the reasons I ended up at UMass Lowell. He served the university with great dedication. . . . Within NEDHO, Gil was a steady presence and served for many years as our treasurer. His contributions to nuclear engineering education and to this community will be dearly missed.”
Bingjing Su, G. C. Pomraning
Nuclear Science and Engineering | Volume 124 | Number 2 | October 1996 | Pages 309-319
Technical Paper | doi.org/10.13182/NSE96-A28580
Articles are hosted by Taylor and Francis Online.
Standard PN theory is well developed as an approximation to the neutron transport equation. However, this theory contains no physics in the sense that it simply represents the angular flux as a sum of polynomials in angle. Thus, standard PN theory (with N finite) cannot qualitatively predict correct asymptotic transport behavior except in the limit of pure scattering. In this paper‚ we modify standard PN theory by incorporating certain transport physics, namely, the Case discrete modes, into a modified PN expansion of the angular flux. The theory resulting from using this modified PN-like expansion predicts the exact transport asymptotic growth/decay length, since it contains the discrete Case eigenvalue. Such modified P3-like equations and associated boundary conditions are derived in planar geometry according to a recently introduced variational calculus. Analyses and numerical calculations reveal that this modified P3-like theory possesses the following features: (a) It reduces to standard P3 theory in the limit of pure scattering; (b) it conserves neutrons but exhibits a scalar flux discontinuity at a material interface; (c) it is shown numerically to be exceedingly accurate, much more accurate than standard P3 theory, in predicting various transport theory behavior for homogeneous problems; and (d) for heterogeneous problems, it is necessary that each material region in the system be sufficiently large for this theory to predict better results than standard P3 theory.
