ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
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!
Latest Magazine Issues
Sep 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
Fusion Science and Technology
August 2025
Latest News
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The 2025 edition is a reinvigoration of the withdrawn ANS-54.8-1988 of the same title.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.
T. O. Passell, R. L. Heath
Nuclear Science and Engineering | Volume 10 | Number 4 | August 1961 | Pages 308-315
doi.org/10.13182/NSE61-A15372
Articles are hosted by Taylor and Francis Online.
Measured values of effective cross sections for fission neutrons obtained for n,p reactions on Ni58, Fe54, Zn64, Mg24, Fe56, Zn67, and Cu65 are 92, 54, 28, 1.2, 0.82, 0.57, and 0.36 mb, respectively. All cross sections are based upon the value 0.60 mb for the n,α reaction on Al27. Measurements were made at the exact center of the EBR-I core. This position has been shown by other investigators to have a neutron energy spectrum similar to that of virgin fission neutrons in the region above 2 Mev. The n,p reaction on Ni58 is shown to have unusual practical advantages as a fast flux monitor. The chemical and physical stability of nickel metal in most reactor coolants, the absence of radioactivities obscuring the Co58, the long half-life of Co58 (72 days), and the ease with which its 0.800 Mev gamma can be measured, are some of these advantages. A major but avoidable drawback is the 1650 barn thermal neutron capture cross section of Co58. A comparison of nickel and sulfur in measuring the fast neutron flux spectrum in beam hole HB-3 of the MTR is included. Evidence is presented which indicates that the correct value for the fission neutron cross section of S32 is 65 mb.