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.
Division Spotlight
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
May 2025
Latest News
DTE Energy studying uprate at Fermi-2, considers Fermi-3’s prospects
DTE Energy, the owner of Fermi nuclear power plant in Michigan, is considering an extended uprate for Unit 2 that would increase its 1,100-MW generation capacity by 150 MW.
S. T. Perkins
Nuclear Science and Engineering | Volume 24 | Number 3 | March 1966 | Pages 284-290
Technical Paper | doi.org/10.13182/NSE66-A17640
Articles are hosted by Taylor and Francis Online.
The neutron spectrum equations are investigated for regions in which the neutron source includes both volume and surface components. The results are thereby applicable to reflected cores and reflector regions. The spectrum is analyzed in the volume-integrated P1 approximation. The difference from the corresponding bare-core relations is an additional source, plus the redefinition of the leakage parameter. It is shown, with the approximation of diffusion theory, that the leakage parameter is always nonpositive. Several simplified forms are also developed for this term. A numerical calculation is presented to show the details of the procedure, and the results are compared to a multiregion analysis.
