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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Fusion Science and Technology
Latest News
A webinar, and a new opportunity to take ANS’s CNP Exam
Applications are now open for the fall 2025 testing period for the American Nuclear Society’s Certified Nuclear Professional (CNP) exam. Applications are being accepted through October 14, and only three testing sessions are offered per year, so it is important to apply soon. The test will be administered from November 12 through December 16. To check eligibility and schedule your exam, click here.
In addition, taking place tomorrow (September 19) from 12:00 noon to 1:00 p.m. (CDT), ANS will host a new webinar, “How to Become a Certified Nuclear Professional.” More information is available below in this article.
Z. J. Bergstrom, M. A. Cusentino, B. D. Wirth
Fusion Science and Technology | Volume 71 | Number 1 | January 2017 | Pages 122-135
Technical Note | doi.org/10.13182/FST16-121
Articles are hosted by Taylor and Francis Online.
Fusion reactor materials experience high ion fluxes and operating temperatures, which will ultimately produce subsurface helium and hydrogen bubbles in the tungsten divertor that can cause surface degradation and impact core plasma performance. Molecular dynamics simulations have been used to evaluate the behavior of hydrogen and helium near a 2-nm bubble or void below a tungsten surface as a function of surface orientation, temperature, gas atom concentration, initial hydrogen distribution, and depth below the surface. A clear tendency for hydrogen to segregate to the bubble-matrix interface is observed in these simulations, regardless of the initial spatial distribution of the hydrogen or simulation parameters. This segregation is due in part to a local minimum in the hydrogen energy at the periphery of the bubble. Further work is required to fully characterize the mechanism of this behavior and to assess the quantities of hydrogen in the bubble and at the bubble periphery.