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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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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Nuclear Technology
Fusion Science and Technology
July 2025
Latest News
Hash Hashemian: Visionary leadership
As Dr. Hashem M. “Hash” Hashemian prepares to step into his term as President of the American Nuclear Society, he is clear that he wants to make the most of this unique moment.
A groundswell in public approval of nuclear is finding a home in growing governmental support that is backed by a tailwind of technological innovation. “Now is a good time to be in nuclear,” Hashemian said, as he explained the criticality of this moment and what he hoped to accomplish as president.
B. Zhao, S. A. Musa, S. I. Abdel-Khalik, M. Yoda
Fusion Science and Technology | Volume 72 | Number 3 | October 2017 | Pages 300-305
Technical Paper | doi.org/10.1080/15361055.2017.1333828
Articles are hosted by Taylor and Francis Online.
The leading candidate for the DEMO divertor is the helium-cooled modular divertor with multiple jets (HEMJ) design, which is to date the only design that has been experimentally shown to accommodate incident steady-state heat fluxes greater than 10 MW/m2. In the HEMJ, the divertor target plates are cooled by 25 jets of different diameters that impinge upon a curved tungsten (W)-alloy surface brazed to a hexagonal W tile. Given the difficulties in manufacturing such a complicated geometry in W and W-alloys, numerical simulations were performed to determine if simplified versions of the HEMJ design could provide similar thermal-hydraulic performance. Parametric studies were performed at fully prototypical conditions using one-way coupled thermo-mechanical and fluid dynamics simulations in ANSYS® Workbench® to determine the effect of varying the jet-to-cooled surface distance, the number, diameter, and spacing of the jet holes (the jets were all assumed to have the same diameter), and the curvature of the cooled surface on the thermal-hydraulic performance. The results for the evaluated 75 different jet array configurations suggest that similar and even superior thermal-hydraulic performance can be provided by several designs. These HEMJ variants with fewer jets and larger holes may reduce fabrication costs and improve reliability. For example, the simulations suggest that a configuration involving flat surfaces with six holes surrounding one central hole, all with a diameter of 1.18 mm at a jet-to-cooled surface distance of 1.25 mm provides a 6.6% higher average heat transfer coefficient (HTC) at a 4.8% lower pressure drop when compared with the HEMJ. The maximum temperature of the outer shell and cooled surface stress are also lower for this design. In all cases, the simulations also suggest that the jet-to-cooled surface distance decreases by approximately 0.2 mm when the temperature increases from ambient to prototypical conditions due to differential thermal expansion of the jets cartridge and the W-alloy pressure boundary.
