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Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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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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.
R. N. Hill, K. O. Ott, J. D. Rhodes
Nuclear Science and Engineering | Volume 103 | Number 1 | September 1989 | Pages 25-36
Technical Paper | doi.org/10.13182/NSE89-A23657
Articles are hosted by Taylor and Francis Online.
Analytical exploratory investigations indicate that transition effects such as streaming cause a considerable spatial variation in the neutron spectra across resonances; streaming leads to opposite effects in the forward and backward directions. The neglect of this coupled spatial/angular variation of the transitory resonance spectra is an approximation that is common to all current group constant generation methodologies. This paper aims at an accurate description of the spatial/angular coupling of the neutron flux across isolated resonances. It appears to be necessary to differentiate between forward- and backward-directed neutron flux components or even to consider components in narrower angular cones. The effects are illustrated for an isolated actinide resonance in a simplified fast reactor blanket problem. The resonance spectra of the directional flux components φ+ and φ‾, and even more so the 90-deg cone components, are shown to deviate significantly from the infinite medium approximation, and the differences increase with penetration. The changes in φ+ lead to a decreasing scattering group constant that enhances neutron transmission; the changes in φ‾ lead to an increasing group constant inhibiting backward scattering. Therefore, the changes in the forward- and backward-directed spectra both lead to increased neutron transmission. Conversely, the flux (φ = φ + + φ‾) is shown to agree closely with the infinite medium approximation both in the analytical formulas and in the numerical solution. The directional effects cancel in the summation. Therefore, flux-weighted (“diffusion theory”) group constants cannot accurately describe the transmission problem, even using transport theory, as the use of flux weighting eliminates the significant directional effects. The forward- and backward-directed flux components are used as weighting spectra to illustrate the group constant changes for a single resonance. Results indicate that these changes have a magnitude that can likely account for calculational underpredictions observed in fast reactor blanket regions.