ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
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Division Spotlight
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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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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.
Luis de Sobrino, Melville Clark, Jr.
Nuclear Science and Engineering | Volume 10 | Number 4 | August 1961 | Pages 384-387
doi.org/10.13182/NSE61-A15383
Articles are hosted by Taylor and Francis Online.
Approximations to the Boltzmann equation including the first two terms in the inverse mass expansion are developed for anisotropic moderators. An asymptotic solution is obtained. The results for beryllium and graphite are compared with the results of the Wilkins approximation. It is seen that this approximation constitutes an improvement over the Wigner and Wilkins gaseous model because the error produced by neglecting higher orders in the inverse mass expansion is in the right direction to account for crystalline binding.
