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.
Edwin M. Pennington
Nuclear Science and Engineering | Volume 19 | Number 2 | June 1964 | Pages 215-220
Technical Paper | doi.org/10.13182/NSE19-02-215
Articles are hosted by Taylor and Francis Online.
First-collision probabilities for a regular lattice of cylindrical fuel rods and moderator are calculated using the assumption that neutrons reaching the outer boundary of the unit cell are returned isotropically. Comparisons are made with results using Fukai's exact method and other approximate methods. The collision probabilities are used in calculating thermal-disadvantage factors which are compared with those from discrete-ordinate calculations using various boundary conditions. The treatment is extended to lattices with cladding on the fuel, and average thermal fluxes are compared with those computed by the THERMOS code. Collision probabilities calculated by the method presented here are in rather good agreement with exact values.