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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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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.
V. Jagannathan, R. P. Jain, Vinod Kumar, H. C. Gupta, P. D. Krishnani
Nuclear Science and Engineering | Volume 104 | Number 3 | March 1990 | Pages 222-238
Technical Paper | doi.org/10.13182/NSE90-A23722
Articles are hosted by Taylor and Francis Online.
A diffusion iterative scheme has been developed to analyze the basic three-dimensional supercell problem encountered in pressurized heavy water reactors (PHWRs). Multigroup transport calculations are performed essentially in one dimension for the fuel cluster cell and the reactivity device (RD) supercell problems. Iterative diffusion calculations are done in one and two dimensions such that the net transport leakages into the fuel cluster or RD are reproduced. The few-group parameters of the fuel cluster or the boundary conditions on the RD surface are modified for this purpose. With these modifications, the three-dimensional supercell problem is treated by diffusion theory. The accuracy of the new scheme is demonstrated against the corresponding transport solutions in both one and three dimensions. A half-bundle-sized constant mesh is proposed for core diffusion analyses. Since the RDs in a PHWR are rather arbitrarily located, it is difficult to perturb the lattice parameters of controlled meshes properly when a constant mesh size is employed. A flux-related weighting scheme is devised to distribute the δ∑’s in meshes falling within the zone of influence of an RD. This core model is compared with a direct method where the supercell concept is avoided and RDs are simulated by internal boundary conditions directly in the core diffusion simulation. Analysis of certain low-power criticals provides the experimental validation of the calculational schemes.