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Division Spotlight
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.
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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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. J. Raffety, J. T. Mihalczo
Nuclear Science and Engineering | Volume 48 | Number 4 | August 1972 | Pages 433-443
Technical Paper | doi.org/10.13182/NSE72-A22511
Articles are hosted by Taylor and Francis Online.
A series of clean critical experiments has been performed with homogeneous mixtures of finely divided U(2)F4 or U(3)F4 dispersed in dispersed in paraffin with H/235U atomic ratios varying from 133 to 972. The assemblies were constructed in rectangular geometry, and minimum critical masses and volumes in cylindrical and spherical geometries were obtained from buckling conversions. The minimum critical spherical volumes of a U(2)F4-paraffin mixture when unreflected and when reflected with an effectively infinite solid hydrogenous material are 199 and 138 liters, respectively, and the minimum critical 235U masses are 7.5 and 5.4 kg, respectively. The experiments with the U(3)F4-paraffin mixtures were not extensive enough to determine experimentally the values at optimum moderation but transport theory calculations indicate that the unreflected and reflected minimum critical volumes are about 93 and 57 liters, respectively, and that the minimum critical masses are about 4.1 and 2.7 kg of 235U, respectively. Measurements of the 238U-to-235U fission ratio indicated that in some assemblies as much as 6.5% of the fissions occurred in 238U. Prompt-neutron decay constants, α = βeff/1 were measured in reflected and unreflected delayed-critical assemblies of several fuel mixtures by the pulsed-neutron technique; the infinite-medium neutron multiplication factor, k∞, for the various fuel mixtures was inferred from height perturbation measurements.Transport theory calculations of k∞ and feff have been made using various cross-section sets.