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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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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The 2025 edition is a reinvigoration of the withdrawn ANS-54.8-1988 of the same title.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.
L. J. Esch
Nuclear Science and Engineering | Volume 16 | Number 2 | June 1963 | Pages 196-201
Technical Paper | doi.org/10.13182/NSE63-A26499
Articles are hosted by Taylor and Francis Online.
The neutron diffusion length in paraffin has been measured by a static technique in the temperature range from 60°C to 130°C. The neutron transport cross section was abstracted from the measured diffusion length. A semiempirical prescription describing the temperature dependence of the neutron transport cross section in paraffin and polyethylene has been derived. The derivation is based on that of the Radkowsky prescription for water. A calculation of the transport cross section in paraffin and polyethylene has been carried out in the temperature range from 20°C to 125°C. The measured transport cross section in paraffin has been compared with that predicted by the prescription. The values agree within 3%. A 14% difference between the values for paraffin and those for water gives credence to the assumption that calculations of the characteristics of plastic moderated critical assemblies can be improved by the use of the proper prescription.
