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
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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.
W. Rothenstein, J. Helholtz
Nuclear Science and Engineering | Volume 24 | Number 4 | April 1966 | Pages 362-374
Technical Paper | doi.org/10.13182/NSE66-A16406
Articles are hosted by Taylor and Francis Online.
It is shown that the most suitable boundary conditions connecting the moments of the angular flux at the two faces of an annular void surrounding the fuel in a reactor lattice cell are obtained from the consistent use of the transport-theory PN approximation in the void as well as in the other media, when N is not restricted to very low values. A different procedure, which is particularly appropriate in diffusion theory, had been used previously by Newmarch and extended to N = 3 and N = 5 by Tait and Clendenin. However, the algebraic difficulties are considerable, and, although their method is preferable to the systematic use of the PN approxi- mation in all media for the lowest values of N, it is not capable of generalization to higher N. Comparisons of the different approaches are given for the lowest-order approximations; the method based on applying the PN approximation to all regions is given in a form suitable for any odd value of N, and numerical results are presented up to N = 11 to show that it converges rapidly.