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
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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!
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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.
Tomas Lefvert
Nuclear Science and Engineering | Volume 54 | Number 4 | August 1974 | Pages 369-375
Technical Paper | doi.org/10.13182/NSE74-A23431
Articles are hosted by Taylor and Francis Online.
The eigenvalue problem of the integral neutron transport equation is studied using generalized first-flight collision probabilities. An exact transformation law for these collision probabilities describes how they change when the total cross section of the medium varies. Applying this transformation law on eigenvalue problems of the integral transport equation leads to several useful results. Thus, an explicit eigenvalue equation for the decay constant is derived, and transformed eigenvalue problems for both the multiplication factor, k, and the decay constant, α, are given in terms of the transport properties of a reference configuration, and of scaling parameters for uniform size and/or density changes. Exact scaling laws for k and α at constant mean-free-path transformations result as a special case. Finally, a general, higher order, nonlinear perturbation theory is given for both the multiplication factor and decay constant eigenvalue problems.