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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.
P. Reuss
Nuclear Science and Engineering | Volume 92 | Number 2 | February 1986 | Pages 261-266
Technical Paper | doi.org/10.13182/NSE86-A18174
Articles are hosted by Taylor and Francis Online.
Because of the large number of heavy nuclide resonances, a detailed neutron flux calculation in the epithermal range cannot be made by standard nuclear reactor codes: It would need several tens of thousands of energy points. However, by using precalculated effective reaction rates, only a few tens of groups are sufficient for accurate spectrum and reaction rate calculations, if a consistent formalism is used. Such a formalism was elaborated in the 1970s by M. Livolant, F. Jeanpierre for the “one resonant nuclide-one resonant zone” problem, and was implemented in the APOLLO code. In practical cases there are several resonant nuclides and often resonant zones of different characteristics, e.g., a lattice constituted with different kinds of pins, a lattice with irregular “water holes,” a fuel element with temperature (therefore Doppler effect) gradients, and so on. Since these problems cannot be correctly treated by APOLLO, a generalization of the formalism was derived. The basic principles were retained, and an algorithm was constructed that would not require too expensive calculations. The Livolant-Jeanpierre theory is briefly summarized, equations for the most general case are presented, some approximations for practical calculations are proposed, and numerical tests on significant examples are discussed.