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
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
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.
Hiroshi Takahashi
Nuclear Science and Engineering | Volume 5 | Number 5 | May 1959 | Pages 338-346
Technical Paper | doi.org/10.13182/NSE59-A25607
Articles are hosted by Taylor and Francis Online.
The thermal neutron energy spectrum in a homogeneous medium has been studied by many authors. In case of heterogeneous reactors, the absorption in fuels is so strong that the thermal neutron energy spectrum in the fuel will have a higher energy than in the moderator. The different temperatures of these media will also cause a difference of spectra. The thermal neutron energy spectra of each medium in a heterogeneous reactor are studied in this paper. The thermal neutron energy spectrum and the neutron temperature in light-water moderated and UO2 fueled reactors were calculated by a numerical method and the approximate Wigner-Wilkins method.
