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
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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
Oct 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
November 2025
Nuclear Technology
Fusion Science and Technology
Latest News
TVA nominees promise to support advanced reactor development
Four nominees to serve on the Tennessee Valley Authority Board of Directors told the Senate Environment and Public Works Committee that they support the build-out of new advanced nuclear reactors to meet the increased energy demand being shouldered by the country’s largest public utility.
Morton R. Fleishman, Harry Soodak
Nuclear Science and Engineering | Volume 7 | Number 3 | March 1960 | Pages 217-227
Technical Paper | doi.org/10.13182/NSE60-A25705
Articles are hosted by Taylor and Francis Online.
The Spinrad three-group theory of the fast effect is formulated. Recipes are presented for determining the necessary cross sections directly from fundamental data and three-group cross sections for various materials are tabulated. A comparison is made between the three-group theory and one-group theory with respect to the calculation of R, the ratio of fast-to-thermal fissions, and it is found that the three-group theory appears to give better agreement with experiments. The three-group values of Є — 1 are about 20% higher than those calculated from the one-group formula.
