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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.
Tsuyoshi Misawa, Seiji Shiroya, Keiji Kanda
Nuclear Technology | Volume 83 | Number 2 | November 1988 | Pages 162-170
Technical Paper | Fission Reactor | doi.org/10.13182/NT88-A34157
Articles are hosted by Taylor and Francis Online.
A criticality safety study on a light water moderated and reflected coupled core loaded with highly enriched uranium fuel was performed in the Kyoto University Critical Assembly. The critical mass and neutron flux distribution were measured systematically as a function of the separation distance between the two cores, varying the H/235U atomic ratio (i.e., the moderator-to-fuel volume ratio). These data were analyzed with the SRAC code system to assess the capability of diffusion theory to analyze the coupled-core system. It was found that the critical mass of the coupled core showed the minimum when the two cores were separated by a certain distance depending on the neutron spectrum in the core region. The neutron flux peak value at the water gap region reached the maximum when the separation distance was 5 to 6 cm. The results calculated with the diffusion code installed in the SRAC system agreed well with the experimental data.
