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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.
Li Mao, J. P. Both, J. C. Nimal
Nuclear Science and Engineering | Volume 130 | Number 2 | October 1998 | Pages 226-238
Technical Paper | doi.org/10.13182/NSE98-A2002
Articles are hosted by Taylor and Francis Online.
The coefficients of a truncated Legendre series are usually used in multigroup cross-section sets to treat the angular distribution for a group-to-group scattering event. Fine energy meshes and low-order Legendre expansions result in negative values in the corresponding multigroup Legendre expansions; therefore, special transfer matrix treatments for multigroup cross sections are needed.The difficulties of the truncated Legendre series representation in treating multigroup transfer are explained. In TRIMARAN-II, two existing standard methods, the equally probable step function (EPSF) representation and the discrete angle representation, which are based on preservation (at least approximately) of the first moments, are studied. The discrete angle representation has the advantage of accurately preserving the moments, but it may cause ray effects; the EPSF representation can eliminate ray effects, but it is not suitable for the treatment of the transfer matrix for material mixtures, because both forward- and backward-peaked scattering are present in this kind of cross section. A new method, the nonequally probable step function (NEPSF) representation, which combines the advantages of both the discrete angle and EPSF representations, is introduced. It can eliminate ray effects and accurately preserve the moments. The conjugate gradient method, powerful for solving multidimensional minimization problems, is used to obtain both the EPSF and NEPSF representations. A problem of neutron transmission in a hydrogenous material is used to compare the three representations. Comparisons of the TRIMARAN-II results with the three representations to those of the TRIPOLI-4 pointwise cross-section Monte Carlo code are given.
