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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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The 2025 edition is a reinvigoration of the withdrawn ANS-54.8-1988 of the same title.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.
William R. McDonell
Nuclear Science and Engineering | Volume 12 | Number 3 | March 1962 | Pages 325-336
Technical Paper | doi.org/10.13182/NSE62-A28082
Articles are hosted by Taylor and Francis Online.
When uranium with preferred orientation is heat treated at low beta phase temperatures and cooled in air, grain coarsening proceeds at a more rapid rate than the loss of preferred orientation. Quenching into water from the beta temperature increases the rate of loss of preferred orientation and refines the grain size. To account for these effects, it is postulated that the transformation from the highly oriented alpha phase to the beta phase is incomplete in short times at low beta phase temperatures, and that during cooling the residual alpha grains serve as centers for retransformation to an oriented, large-grained alpha phase. Quenching increases nucleation from the beta phase, and results in a structure that is finer grained and more randomly oriented.