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
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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.
Ely M. Gelbard
Nuclear Science and Engineering | Volume 54 | Number 3 | July 1974 | Pages 327-340
Technical Paper | doi.org/10.13182/NSE74-A23423
Articles are hosted by Taylor and Francis Online.
Diffusion coefficients are computed for a typical lattice cell of the zero-power plutonium reactor experiments using the methods of Benoist and Bonalumi. It is noted that the diffusion coefficients, Dx, for leakage normal to the plates, as defined by Benoist and by Bonalumi, are both double valued. The spread between Benoist’s x-diffusion coefficient is, in the lattice cell, over half as large as the difference between Dx and Dy. Bonalumi’s x-diffusion coefficients are much farther apart, the interval between them being considerably larger than the difference between Dx and Dy. Neither the Benoist nor the Bonalumi method yields homogenized diffusion coefficients that preserve fluxes, reaction rates, or eigenvalues. Using an approach similar to that of Deniz, the diffusion coefficient is redefined and constructed in such a way as to guarantee that eigenvalues will be preserved in the homogenization process. The relation between the new diffusion coefficients and the Benoist coefficients is discussed.