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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.
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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.
S. N. Purohit
Nuclear Science and Engineering | Volume 9 | Number 3 | March 1961 | Pages 305-313
Technical Paper | doi.org/10.13182/NSE61-A25881
Articles are hosted by Taylor and Francis Online.
The time-dependent energy spectra, for times greater than the slowing-down time, were generated in a monatomic heavy gas with the help of a multigroup formalism. These spectra were obtained for the infinite as well as finite media of beryllium and graphite. The behavior of asymptotic energy spectra during the last stage of neutron thermalization and diffusion periods was studied. The thermalization time constant for the establishment of the final Maxwellian velocity distribution of neutrons, in a monatomic heavy gas, was estimated to be equal to (1.176ξΣs0υ0)−1. Total thermalization times for neutrons in beryllium and graphite were found to be equal to 114 and 238 µsec, respectively. Using the energy-dependent transport mean free path, the diffusion cooling coefficient for beryllium was calculated to be equal to 0.890 cm2 For graphite, under the constant diffusion coefficient assumption, the diffusion cooling coefficient was determined to be equal to 1.922 cm2.