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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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Ho Nieh nominated to the NRC
Nieh
President Trump recently nominated Ho Nieh for the role of commissioner in the Nuclear Regulatory Commission through the remainder of a term that will expire June 30, 2029.
Nieh has been the vice president of regulatory affairs at Southern Nuclear since 2021, though he is currently working as a loaned executive at the Institute of Nuclear Power Operations, where he has been for more than a year.
Nieh’s experience: Nieh started his career at the Knolls Atomic Power Laboratory, where he worked primarily as a nuclear plant engineer and contributed as a civilian instructor in the U.S. Navy’s Nuclear Power Program.
From there, he joined the NRC in 1997 as a project engineer. In more than 19 years of service at the organization, he served in a variety of key leadership roles, including division director of Reactor Projects, division director of Inspection and Regional Support, and director of the Office of Nuclear Reactor Regulation.
Changho Lee, Hansol Park, Yeon Sang Jung, Cooper Trucks
Nuclear Science and Engineering | Volume 199 | Number 1 | April 2025 | Pages S42-S55
Review Article | doi.org/10.1080/00295639.2024.2348855
Articles are hosted by Taylor and Francis Online.
High-fidelity deterministic steady-state simulations of the Empire microreactor problem were conducted using the discontinuous finite element method–based discrete ordinate solver in Griffin, accompanied by the online cross-section self-shielding application programming interface (SSAPI). The 68-group cross-section libraries for SSAPI were generated through a series of Python scripts and using a combination of Serpent2, NJOY, and MC2-3 with ENDF/B-VII.0, VII.1, and VIII.0 data. Additionally, the 27-group libraries were generated as well to improve computational performance while maintaining the solution accuracy. The capabilities of Griffin with these three ENDF/B cross-section libraries were rigorously tested across various Empire microreactor benchmark problems, including fuel assembly and two- and three-dimensional cores with control drums rotated in or out. The calculation results convincingly demonstrated that Griffin with the cross-section libraries and SSAPI achieves accurate simulations of the Empire microreactor cores, exhibiting accuracy in terms of eigenvalue, control drum reactivity worth, and pin power distribution when compared to corresponding Serpent2 solutions.
