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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Latest News
Senate EPW Committee to hold Nieh nomination hearing
Nieh
The Senate Environment and Public Works Committee will hold a nomination hearing Wednesday for Ho Nieh, President Donald Trump’s nominee to serve as commission at the Nuclear Regulatory Commission.
Trump nominated Nieh on July 30 to serve as NRC commissioner the remainder of a term that will expire June 30, 2029, as Nuclear NewsWire previously reported.
Nieh has been vice president of regulatory affairs at Southern Nuclear since 2021, though since June 2024 he has been at the Institute of Nuclear Power Operations as a loaned executive.
A return to the NRC: If confirmed by the Senate, Nieh would be returning to the NRC after three previous stints totaling nearly 20 years.
Gang Li
Nuclear Science and Engineering | Volume 180 | Number 2 | June 2015 | Pages 154-171
Technical Paper | doi.org/10.13182/NSE13-87
Articles are hosted by Taylor and Francis Online.
This investigation is to design a nonlinear pressurized water reactor (PWR) core load-following control system with self-stability for regulating the core power and axial power difference within a target band. A two-point–based nonlinear PWR core without boron and with a power rod and an axial offset rod is modeled. By proposing the gap metric of the core to qualify the core nonlinearity, the linearized multimodel single-variable core under case 1 (multivariable core under case 2) classified by two movable regions of the power rod is modeled. Linearized models of the core at seven power levels are chosen as local models of the core to substitute the nonlinear core model for each case. Based on H-infinity (H∞) control theories, the linear matrix inequalities method is adopted to design a H∞ output-feedback controller of every local model, which is a local controller of the nonlinear core of each case. In terms of the flexibility idea of control presented, the core load-following control system for each case is established. A theorem is deduced to analyze the global stability of the system of each case. Ultimately, simulation results show that the H∞ multimodel control strategy is effective for the core of each case.