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Aerospace Nuclear Science & Technology
Organized to promote the advancement of knowledge in the use of nuclear science and technologies in the aerospace application. Specialized nuclear-based technologies and applications are needed to advance the state-of-the-art in aerospace design, engineering and operations to explore planetary bodies in our solar system and beyond, plus enhance the safety of air travel, especially high speed air travel. Areas of interest will include but are not limited to the creation of nuclear-based power and propulsion systems, multifunctional materials to protect humans and electronic components from atmospheric, space, and nuclear power system radiation, human factor strategies for the safety and reliable operation of nuclear power and propulsion plants by non-specialized personnel and more.
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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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Latest News
DOE extends Centrus’s HALEU production contract by one year
Centrus Energy has announced that it has secured a contract extension from the Department of Energy to continue—for one year—its ongoing high-assay low-enriched uranium (HALEU) production at the American Centrifuge Plant in Piketon, Ohio, at an annual rate of 900 kilograms of HALEU UF6. According to Centrus, the extension is valued at about $110 million through June 30, 2026.
J. Ligou
Nuclear Science and Engineering | Volume 50 | Number 2 | February 1973 | Pages 135-146
Technical Paper | doi.org/10.13182/NSE73-A23237
Articles are hosted by Taylor and Francis Online.
Polynomial approximations in space are used for solving the integral transport equations for multilayers systems, in one dimensional spherical or cylindrical geometry with scattering anisotropy. These polynomial approximations are applied to the neutron sources (collided neutrons) in each layer, in such a way that the mean quadratic error is a minimum. The form of this approximation allows a less complicated treatment of the anisotropic components of the collided neutron sources than the usual approach (collision probabilities for uniform sources). In order to reduce the number of necessary integral equations when the scattering anisotropy is present, some differential equations relating the spherical harmonics components of the angular flux are used. This is very useful from a numerical point of view, especially when polynomial approximations in space are introduced. A very important link between the scattering anisotropy and the degree of polynomial approximations is also derived. Based on this method the SHADOK code was written. Several numerical examples dealing with multigroup calculations of fast critical assemblies for spherical geometry (FRO-GODIVA-TOPSY-ZPR.43/8) are given. The results show that (a) the large optical dimensions are not a problem for this improved integral method, (b) the scattering.anisotropy (at least PI) does not increase the time of computation, and (c) the heterogeneous systems (reflected cores) can be calculated easily. The calculations with the proposed method are considerably faster than those of the SN method.
