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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Powering the future: How the DOE is fueling nuclear fuel cycle research and development
As global interest in nuclear energy surges, the United States must remain at the forefront of research and development to ensure national energy security, advance nuclear technologies, and promote international cooperation on safety and nonproliferation. A crucial step in achieving this is analyzing how funding and resources are allocated to better understand how to direct future research and development. The Department of Energy has spearheaded this effort by funding hundreds of research projects across the country through the Nuclear Energy University Program (NEUP). This initiative has empowered dozens of universities to collaborate toward a nuclear-friendly future.
G. C. Pomraning, Robert Rulko, Bingjing Su
Nuclear Science and Engineering | Volume 118 | Number 1 | September 1994 | Pages 1-23
Technical Paper | doi.org/10.13182/NSE94-A19018
Articles are hosted by Taylor and Francis Online.
It has recently been argued that in planar geometry, P2 theory is more accurate (but no more complex) than P1 (diffusion) theory as an approximation to transport theory. This argument was based upon analytic comparisons as well as results from numerical test problems. On the analytic side, the P2 fundamental decay length is more accurate than the corresponding P1 decay length. One of the purposes of this paper is to show that the P2 expansion is, in fact, the optimal choice taken from a large family of expansions in predicting this decay length. Further, P2 theory exhibits scalar flux discontinuities at material interfaces, which can be considered as accounting for internal transport boundary layers. By contrast, the P1 scalar flux is everywhere continuous. The main purpose of this paper is to present an entire family of diffusion equations that contain flux discontinuities at material interfaces All members of this family predict the exact transport fundamental decay length (the discrete Case eigenvalue). One preferred member of this family is shown to be exceedingly accurate in predicting various transport theory behavior for homogeneous source-free problems. The formalism used to derive these diffusion theories is the variational calculus, including boundary considerations that lead to the diffusive boundary conditions.