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Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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.
Tadashi Yoshida
Nuclear Science and Engineering | Volume 72 | Number 3 | December 1979 | Pages 361-365
Technical Note | doi.org/10.13182/NSE79-A20393
Articles are hosted by Taylor and Francis Online.
A method is presented for determining by numerical integration a diffusion coefficient, Dz, applicable to the axial direction of a control rod follower region in a sodium-cooled fast reactor. By comparing criticality values from transport and diffusion theory for a simplified reactor model, we are able to show that this Dz applies well to the followers from the viewpoint of the calculated criticality factor, keff. By use of the same model, an inter comparison is also made between the present and other definitions of Dz. By using the present Dz, as a conclusion, we show that the currently used D (= 1/3Σ) for control rod followers leads to an underestimation of keff by ∼0.3% for a typical 300-MW(electric) class liquid-metal fast breeder reactor with one-third of the control rods inserted, which may increase to 0.4 to 0.5% for a case where all control rods are withdrawn.