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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Hash Hashemian: Visionary leadership
As Dr. Hashem M. “Hash” Hashemian prepares to step into his term as President of the American Nuclear Society, he is clear that he wants to make the most of this unique moment.
A groundswell in public approval of nuclear is finding a home in growing governmental support that is backed by a tailwind of technological innovation. “Now is a good time to be in nuclear,” Hashemian said, as he explained the criticality of this moment and what he hoped to accomplish as president.
Earl J. Schulz, John C. Lee
Nuclear Science and Engineering | Volume 73 | Number 2 | February 1980 | Pages 140-152
Technical Paper | doi.org/10.13182/NSE80-A18694
Articles are hosted by Taylor and Francis Online.
Time-optimal control of axial xenon oscillations in pressurized water reactors is investigated in the present study, properly accounting for operating constraints on the allowable axial offset (AO) band. The system equation describing the spatial xenon oscillations has been reformulated using a lambda mode expansion in a form that readily allows a physical interpretation of the state vector and the system equation. In particular, AO measurements can be used to define the entire system parameters completely. Previous optimal control studies have been limited to the case of controls to the origin in the xenon-iodine phase plane. Our present investigation indicates that time-optimal controls should, in general, involve bang-bang controls to a line segment in this phase plane, subject to a band constraint on allowable AO or available control strength. A suboptimal control strategy, which can be applied directly in actual operating conditions without the aid of on-line computers, is also proposed. Verification of the proposed time-optimal control strategies is performed through computer simulations of xenon-induced transients.