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Conference Spotlight
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.
Charles W. Bagnal, Jr., Gerard P. Cavanaugh, Robert P. Harris, Regis A. Matzie, Laszlo B. Tarko
Nuclear Technology | Volume 68 | Number 1 | January 1985 | Pages 7-17
Technical Paper | Fission Reactor | doi.org/10.13182/NT85-A33562
Articles are hosted by Taylor and Francis Online.
Fuel management and core periphery modifications are examined for slowing pressurized water reactor (PWR) pressure vessel embrittlement by reducing the incident fast flux to the vessel Such strategies can help to mitigate the consequences of pressurized thermal shock, a current licensing concern. For most operating PWRs, a factor of 2 reduction in fast flux to the reactor vessel critical welds can be achieved with little or no penalty in power peaking (3% or less), which implies only a small degradation in thermal margin. This can be accomplished with low leakage fuel management, which places twice-burned fuel near these welds. To achieve higher reduction factors, materials with good fast neutron attenuation properties must be used in conjunction with low leakage fuel management. For example, a reduction factor of 3 implies a limited use of dummy stainless steel assemblies (with an associated increase in power peaking of at least 8%) or the use of stainless steel patches between the core and the vessel In general, a factor of 3 reduction in fast flux is a practical upper limit to what can be reasonably achieved without significant degradation of thermal margin. A factor of 5 reduction may be possible in some cases, but would require the liberal use of dummy assemblies and/or stainless steel patches; a fast flux reduction by a factor of >5 would most likely require power derating.