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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.
S. Ganesan
Nuclear Science and Engineering | Volume 74 | Number 1 | April 1980 | Pages 49-51
Technical Note | doi.org/10.13182/NSE80-A18946
Articles are hosted by Taylor and Francis Online.
It is well known that in the unresolved resonance region, cross sections are treated by a statistical formulation and that the nonuniqueness of the mean resonance data set used to represent the cross sections for various fertile and fissile nuclides has an impact on the calculations of the Doppler coefficient and the fission and capture rate distributions of the heavy elements in a fast power reactor. In this Note, the corresponding uncertainty associated with the calculation of the central Doppler worth in the critical assemblies is indicated. Through the choice of the mean resonance data sets, it is possible to vary the self-shielded cross sections to some extent and to vary the temperature derivatives of the self-shielded cross sections by a significant amount so as to improve the agreement between experiments and calculations for central Doppler worths. This adjustment can be performed without significantly altering the infinite dilution cross sections that are recommended in the unresolved resonance region. This approach is illustrated with sample calculations performed for the central 235U Doppler worth in the ZPR-6-7 assembly.
