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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.
Abhishek Saxena, Jan Eiholzer, Harshank Agarwal, Horst-Michael Prasser
Nuclear Technology | Volume 196 | Number 3 | December 2016 | Pages 568-587
Technical Paper | doi.org/10.13182/NT16-20
Articles are hosted by Taylor and Francis Online.
The thermal-hydraulic design characteristics of a boiling water reactor are strongly dependent on the physics of heat-removing mechanisms from nuclear rods. Performance is often limited by a lack of understanding of the heat and momentum transfer in thin liquid films close to dryout. This is particularly important with regard to power uprates of reactors. Flow control by functional spacers equipped with vanes adds complexity to the flow behavior. Instead of improving the heat removal, they can cause a local reduction of the film thickness under unfavorable conditions. This work presents a novel experimental technique to measure the velocity of the liquid phase and to study the turbulent mixing of a passive scalar in the film. The studies were performed in vertical annular flow in a double-subchannel geometry. The liquid film was labeled by either continuous or pulsed tracer injection. An electrically conductive tracer (salt solution) is injected into the film consisting of deionized water. The salt is traced using a liquid film sensor, a high-frequency nonintrusive conductivity-based technique. The experiments are conducted with and without a swirl-type spacer to quantify the effect of the spacers on the film flow for different gas and liquid flow rates. An ensemble averaging of the data obtained from individual injection pulses provides time-averaged liquid velocities in the film. The turbulent dispersion was characterized by analyzing the spread of the tracer in axial and lateral directions. Spacer vanes are found to induce a characteristic transverse movement of the liquid in the film. The effect of waves on mixing is analyzed and is found to enhance it.