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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.
Jorma Karppinen, Rob M. Versluis, Bjørn Blomsnes
Nuclear Science and Engineering | Volume 71 | Number 1 | July 1979 | Pages 1-17
Technical Paper | doi.org/10.13182/NSE79-A20325
Articles are hosted by Taylor and Francis Online.
The problem of controlling the total power and power distribution in a large pressurized water reactor (PWR) core to follow a known time-varying load schedule has been formulated as a multistage optimization problem. The control problem is solved subject to hard constraints, which can be applied on total power, control variables and their rate of change, local power densities and their rate of change, and on more global power distribution measures such as axial and quadrant offsets. Based on a three-dimensional linearized nodal core model with some slightly nonlinear features, the optimal control problem is solved by quadratic programming. The method, called multistage mathematical programming, has been studied in simulations. A large PWR core, which was unstable with respect to both axial and azimuthal xenon oscillations, was represented by a simplified three-dimensional nonlinear nodal core simulator model. The three-dimensional oscillations were successfully damped at constant load, and an efficient anticipatory control was obtained for load cycling operation.
