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
2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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
Aug 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
October 2024
Nuclear Technology
Fusion Science and Technology
August 2024
Latest News
New laws offer nuclear industry incentives for existing power plant uprates
This year, the U.S. nuclear industry received a much-needed economic boost that could help preserve operating nuclear power plants and incentivize upgrades that extend their lifespan and power output.
Signed into law in 2022, the Inflation Reduction Act offers production tax credits (PTCs) for existing nuclear power plants and either PTCs or investment tax credits (ITCs) for new carbon-free generation. These credits could make power uprates—increasing the maximum power level at which a commercial plant may operate—a much more appealing option for utilities.
K. L. Thomsen
Nuclear Science and Engineering | Volume 119 | Number 3 | March 1995 | Pages 153-166
Technical Paper | doi.org/10.13182/NSE95-A24081
Articles are hosted by Taylor and Francis Online.
Efficient methods for the evaluation of collision, escape, and transmission probabilities in the flat-flux, isotropic approximation have been developed for various heterogeneous pin cells. The cells may be either cylindricalized or square with the moderator treated as either a single region or subdivided into the four segments between the diagonals. The conventional “Flurig” scheme by Carlvik is applied to the circular regions and to the four partial surfaces in the cylindricalized cases. For the noncircular regions and surfaces of the square-cell types, the numerical integration in both the radial and the angular direction is based on Gaussian quadrature. The mesh layout is designed with due regard to the directions to corners and vertices to avoid overlap between neighboring regions or surfaces. For rays outside the circular regions, the integration in the radial direction is performed analytically. Furthermore, the symmetry properties as well as the reciprocity and conservation relations are utilized to the maximum possible extent. Thus, high efficiency is achieved, requiring only a few mesh points in both directions as demonstrated by application to various test cases from the literature.