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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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A new ANSI/ANS standard for liquid metal fire protection published
ANSI/ANS-54.8-2025, Liquid Metal Fire Protection in LMR Plants, received approval from the American National Standards Institute on September 2 and is now available for purchase.
The 2025 edition is a reinvigoration of the withdrawn ANS-54.8-1988 of the same title. The Advanced Reactor Codes and Standards Collaborative (ARCSC) identified the need for a current version of the standard via an industry survey.
Typical liquid metal reactor designs use liquid sodium as the coolant for both the primary and intermediate heat-transport systems. In addition, liquid sodium and NaK (a mixture of sodium and potassium that is liquid at room temperature) are often used in auxiliary heat-removal systems. Since these liquid metals can react readily with oxygen, water, and other compounds, special precautions must be taken in the design, construction, testing, and maintenance of the sodium/NaK systems to ensure that the potential for leakage is very small.
G. P. Calame, F. D. Federighi, P. A. Ombrellaro
Nuclear Science and Engineering | Volume 10 | Number 1 | May 1961 | Pages 31-39
Technical Paper | doi.org/10.13182/NSE61-A25926
Articles are hosted by Taylor and Francis Online.
A variational procedure for calculating thermal cross sections and diffusion theory parameters is described. The method permits the calculation of an approximate lethargy-dependent Wigner Wilkins flux spectrum for a region as a linear combination of two lethargy- and temperature-dependent base spectra. The coefficients for linearly combining the base spectra are provided by the theory and once the coefficients are calculated the flux is determined. The average microscopic cross sections and diffusion theory parameters for the region are calculated from a flux weighted average of lethargy-dependent microscopic cross sections and diffusion constants. Cross sections and diffusion theory parameters calculated in this manner agree well with those obtained from the SOFOCATE code.
