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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.
Anil Kumar
Nuclear Science and Engineering | Volume 81 | Number 1 | May 1982 | Pages 66-74
Technical Paper | doi.org/10.13182/NSE82-A19595
Articles are hosted by Taylor and Francis Online.
The neutron collision escape probability from a medium depends on the shape of spatial distribution of the source. The case of a uniform or flat source distribution has been investigated extensively from time to time. In the present work, the case of bare homogeneous reactor assemblies having a centrally peaked neutron source distribution has been analyzed for predicting collision escape probability as a function of assembly size measured in terms of the optical mean chord length . An approximation, known as the modified Wigner rational approximation, is derived and is given by where pE(W) stands for the collision escape probability from a bare homogeneous reactor assembly; ϵ1 and ϵ2 are geometry-dependent parameters. These parameters have been determined for infinite slab, infinite cylinder, sphere, cube, and finite cylinders of height-to-diameter ratio varying from 0.1 to 20. It is shown that it is possible to predict the collision escape probability within approximately ±2% of the exact value for , ranging from 0 to 20 mean-free-paths (mfp). Generally, for a given the collision escape probability value for the centrally peaked source is lower than that for the uniform source. But it is found that for very thin infinite slab assemblies of optical mean chord length 1.5 mfp, the collision escape probability for centrally peaked source distribution is higher than that for uniform source distribution. The reason for this anomaly is discussed.