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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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.
Masayuki Nakagawa, Hideaki Inoue
Nuclear Science and Engineering | Volume 83 | Number 2 | February 1983 | Pages 214-228
Technical Paper | doi.org/10.13182/NSE83-A18215
Articles are hosted by Taylor and Francis Online.
The double heterogeneity effect due to the fuel pin and the subassembly is estimated for neutronics parameters of a prototype fast power reactor. Both of the heterogeneity effects caused by the flux fine structure and the resonance shielding are taken into account. The model of the hexagonal unit subassembly consists of the smeared fuel, the wrapper tube, and the outer sodium regions, where the average cross sections of the smeared fuel region are obtained by a unit pin cell calculation in cylindrical geometry. It is shown that the equivalent smeared model agrees well with the refined cluster model. A formula to define the background cross section of the fuel isotopes is derived based on the rational approximation, and its accuracy is examined. This formula can take into account the contribution from the wrapper tube to the background cross sections of each ring of fuel pin array. The heterogeneity effect of the whole reactor model is calculated based on two-dimensional diffusion theory and perturbation theory. The double heterogeneity effect is found to be 0.5%Δk for keff, the positive sodium-void worth is reduced by 26%, and the negative Doppler reactivity increases by 7% for a prototype fast breeder reactor. These results are considerably larger than the estimates made by earlier workers. These effects are significant from the viewpoint of target accuracy goals in fast power reactor design.
