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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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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.
Anil Kumar
Nuclear Science and Engineering | Volume 82 | Number 3 | December 1982 | Pages 354-358
Technical Note | doi.org/10.13182/NSE82-A19396
Articles are hosted by Taylor and Francis Online.
In the considerations of recriticality of molten fuel assemblies, the presence of bubbles in the fuel plays an important role. In such a situation, there are two opposing contributions to reactivity from (a) the phenomenon of neutron streaming in bubbles (negative contribution) and (b) the phenomenon of changing neutron self-multiplication in the fuel (positive contribution). It is not possible to accurately calculate the individual reactivity contributions of the two phenomena using multidimensional transport theory or Monte Carlo codes. A simple diffusion theory expression given by Nicholson and Goldsmith for estimating reactivity contribution due to neutron streaming alone has been used extensively. As a part of the present contribution, first an attempt has been made to improve the applicability of the Nicholson-Goldsmith work by expressing extrapolation length in terms of the root-mean-square free path in the assembly. It is found that the application of the Trombay criticality formula, particularly its “modified Wigner rational variant,” leads to an expression for bubble reactivity worth, due to neutron streaming alone, that yields the closest agreement with the bubble worth values computed from the two-dimensional transport theory code TWOTRAN and the Monte Carlo code KENO.
