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
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
Meeting 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
Jun 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
July 2025
Fusion Science and Technology
Latest News
NRC cuts fees by 50 percent for advanced reactor applicants
The Nuclear Regulatory Commission has announced it has amended regulations for the licensing, inspection, special projects, and annual fees it will charge applicants and licensees for fiscal year 2025.
Floro Miraldi, Melville Clark, Jr.
Nuclear Science and Engineering | Volume 11 | Number 3 | November 1961 | Pages 246-255
Technical Paper | doi.org/10.13182/NSE61-A25999
Articles are hosted by Taylor and Francis Online.
The critical parameters of coupled, fissionable assemblies in close proximity to one another are studied by differential equations for the conservation of neutrons. The coupling between the assemblies is taken into account by the use of approximate boundary conditions derived from expressions for the average neutron flow between the assemblies. Critical equations are found from the one and two group diffusion theories and from the P3 approximation/The results are compared with existing experimental data. The present methods are especially suited to the study of arrays of prisms.
