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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.
D. C. Hunt, C. L. Schuske
Nuclear Technology | Volume 22 | Number 2 | May 1974 | Pages 263-274
Reactor | doi.org/10.13182/NT74-A31408
Articles are hosted by Taylor and Francis Online.
Minimum critical masses are calculated for arrays of fissile metal and oxide rods or metal plates spaced in water. The composition of the fissile materials investigated were 96% 239Pu and 4% 240Pu or 93.4% 235U and 6.6% 238U. In addition, minimum critical masses were computed for arrays of plutonium and uranium metal cubes spaced in water. These studies were made to aid the criticality engineer in evaluating fabrication and storage problems involving the handling of various fissile shapes in hydrogenous media. Results were calculated in terms of array minimum critical masses as a function of the volume-to-surface ratio (V/S) of an array element. The minimum critical mass for cube arrays was found to remain constant over a wide range of V/S values, while the minimum critical mass of plate arrays always decreased with decreasing V/S rod arrays exhibited an intermediate behavior. Oxide arrays generally had smaller critical masses than corresponding metal arrays because of their smaller self-shielding factors.
