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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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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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Empowering the next generation: ANS’s newest book focuses on careers in nuclear energy
A new career guide for the nuclear energy industry is now available: The Nuclear Empowered Workforce by Earnestine Johnson. Drawing on more than 30 years of experience across 16 nuclear facilities, Johnson offers a practical, insightful look into some of the many career paths available in commercial nuclear power. To mark the release, Johnson sat down with Nuclear News for a wide-ranging conversation about her career, her motivation for writing the book, and her advice for the next generation of nuclear professionals.
When Johnson began her career at engineering services company Stone & Webster, she entered a field still reeling from the effects of the Three Mile Island incident in 1979, nearly 15 years earlier. Her hiring cohort was the first group of new engineering graduates the company had brought on since TMI, a reflection of the industry-wide pause in nuclear construction. Her first long-term assignment—at the Millstone site in Waterford, Conn., helping resolve design issues stemming from TMI—marked the beginning of a long and varied career that spanned positions across the country.
R. C. Berkan, B. R. Upadhyaya, L. H. Tsoukalas, R. A. Kisner
Nuclear Science and Engineering | Volume 109 | Number 2 | October 1991 | Pages 188-199
Technical Paper | doi.org/10.13182/NSE91-A28517
Articles are hosted by Taylor and Francis Online.
Axial flux shape control in large pressurized water reactors constitutes one of the most challenging control problems in the nuclear field. In commercial plants, the practical solutions are obtained at the expense of departure from the most economical operational conditions, often due to the difficulties in monitoring xenon-induced oscillations and inadequate control actions. The concept of inverse dynamics in control is introduced as an alternative approach for spatial control. The method is tested through computer simulations using a validated nonlinear model that successfully represents the limit-cycle behavior. Compared with the widely used half-cycling strategy or the proposed optimal control methods in the literature, the use of inverse dynamics for partial-length rod control yields desirable stability characteristics. The return to target axial offset exhibits a smooth transition without any residual flux oscillations between the upper and lower halves of the core. The proposed approach consists of a set of nonlinear algebraic equations for control with single-step solutions. Thus, it is easier to implement compared with iterative or integral techniques.