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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.
G. C. Baldwin
Nuclear Science and Engineering | Volume 6 | Number 4 | October 1959 | Pages 320-327
Technical Paper | doi.org/10.13182/NSE59-A28851
Articles are hosted by Taylor and Francis Online.
The kinetics of the two-core configuration of the Argonaut reactor is examined. In this reactor two slightly subcritical slabs two feet apart are immersed in a large graphite reflector. The system achieves criticality by the small interaction due to exchange of thermal neutrons between the cores. The kinetic equations are derived by including an interaction term with the source terms of the thermal neutron diffusion equation, and writing a separate diffusion equation for each slab. This analysis accounts for observations that the ratio of flux levels in the two cores may depart considerably from unity although the reactor shows a single stable period. It is shown that the reactivity change which a rod in one core must introduce to restore criticality after a change is made in the other core is generally not equal in magnitude to that of the change which it compensates. Flux ratio as well as period must be known to determine the excess reactivities; conventional rod calibration data must be corrected for a progressive shift in flux ratio as reactivity is traded between rods. The rod drop method is discussed with two examples; a single relation does not suffice to describe the rod drop procedure. The single transfer function of a simple reactor system is replaced by a set of six transfer functions for the two-core system, two of which are derived for illustration. Even though an oscillator may be located midway between them, the amplitudes and phases of flux in the two cores will not agree except in the special situation of identical cores and equal flux levels. This complicates the problem of regulation.
