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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.
Pramila Mohan, Rajesh Mohan, Feroz Ahmed, L. S. Kothari, Hiroyuki Kadotani
Nuclear Science and Engineering | Volume 94 | Number 1 | September 1986 | Pages 87-93
Technical Note | doi.org/10.13182/NSE86-A17121
Articles are hosted by Taylor and Francis Online.
The multigroup space eigenvalues and eigenfunctions of a one-dimensional steady-state diffusion theory operator have been used to study the spatial behavior of a fast neutron field in certain thorium systems. The nuclear data used are from the 26-group ABBN data set. It has been shown that for a fast thorium system, unlike a fast uranium system, all the space eigenvalues lie in the continuum and no discrete space eigenvalue exists. A fast thorium system behaves more like a fast nonmultiplying system. The spectra shifts continuously to lower energies as one moves away from the source; however, pseudoasymptotic conditions are established in certain distance ranges. In order to test the validity of the diffusion theory and eigenfunction expansion method, results have also been obtained using transport theory. In all cases the two sets of results are in reasonably good agreement. To see the effect of geometry, the spectra at certain distances inside a 1-m-thick thorium slab are compared with the corresponding spectra inside a thorium sphere of 1-m radius. At all distances the normalized slab and sphere spectra are nearly the same.