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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
Fusion Science and Technology
July 2025
Latest News
Spent fuel transfer project completed at INL
Work crews at Idaho National Laboratory have transferred 40 spent nuclear fuel canisters into long-term storage vaults, the Department of Energy’s Office of Environmental Management has reported.
Hiroshi Takahashi
Nuclear Science and Engineering | Volume 26 | Number 2 | October 1966 | Pages 254-261
Technical Paper | doi.org/10.13182/NSE66-A28167
Articles are hosted by Taylor and Francis Online.
The method for calculating the generalized first-flight collision probability in a lattice system with a certain total cross section by the exact generalized first-flight collision probability in a system of the same geometry, having a different standard total cross section, is presented. The time required to calculate the multigroup integral transport problem, can be reduced greatly using this approximation; a large part of the time is consumed by the numerical integral calculation of the collision probabilities in all the energy groups. It is proved that the approximate collision probabilities obtained satisfy the conditions, i.e., the neutron conservation and the reciprocity relation. It is also shown by numerical calculation that the zero'th approximation using the first-flight collision probability gives very good values in the isolated or latticed systems.