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 Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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.
Mark L. Williams, Harish Manohara
Nuclear Science and Engineering | Volume 111 | Number 4 | August 1992 | Pages 345-367
Technical Paper | doi.org/10.13182/NSE92-A15483
Articles are hosted by Taylor and Francis Online.
Contributons are the special particles distributed among a general population that generate the response observed on a specified detector. Contributon slowing-down theory describes the transfer of the response through space and energy as it is carried by contributons from the source to the detector. The response flow through space-energy and space-lethargy obeys the contributon slowing-down equation, which expresses conservation of contributons. A four-dimensional vector field is introduced to identify space and energy channels followed by the contributons, and is used to define response flow lines through space-lethargy. Numerical expressions are presented to compute the response current and slowing-down density that define the components of the response flow field. It is shown how these variables can be used to perform energy channel theory analysis of a particle transport problem. The method is applied to two realistic problems. The first determines contributon transport channels followed through space-energy by fission neutrons produced in a pressurized water reactor as they travel from the core to the reactor cavity region, where they activate surveillance dosimeters. The second examines the response transfer from a nuclear weapon burst as it is carried by contributons through space-lethargy channels in air to detectors located at some distance from ground-zero.