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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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.
Cliff B. Davis
Nuclear Technology | Volume 90 | Number 3 | June 1990 | Pages 286-293
Technical Paper | RELAP/MOD2 / Nuclear Safety | doi.org/10.13182/NT90-A34394
Articles are hosted by Taylor and Francis Online.
The possibility of a flow instability in a fuel assembly during a hypothetical loss-of-coolant accident (LOCA) in the production reactors at the Savannah River Site (SRS) is currently the subject of many analyses. The Bingham pumps, which circulate flow through the Savannah River reactors, may be susceptible to cavitation because of the decrease in pressure that accompanies a LOCA. Cavitation in the Bingham pumps during a LOCA could reduce the forced flow through the assemblies and thus could promote flow instability. An analysis was performed at the Idaho National Engineering Laboratory to aid in the evaluation of the potential significance of cavitation on flow instability. The RELAP5 computer code and a model of the L-Reactor at the SRS were the primary analysis tools. A cavitation model was developed using correlations generated at Savannah River and the RELAP5 control system. Benchmark comparisons were performed between the RELAP5 cavitation model and cavitation tests performed in L-Reactor. Best-estimate calculations of a LOCA initiated by a double-ended guillotine break in the inlet piping to the reactor were then performed for a range of core powers. The LOCA calculations were used to determine the initial core power leading to the onset of cavitation and the effects of cavitation on system response. Cavitation was calculated to occur in the broken loop when the initial core power was >1400 MW. Cavitation did not cause a catastrophic reduction in core flow. The effects of cavitation were self-limiting because of feedback among the pump head, loop flow, and the available and required net positive suction head.