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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. A. Bennett
Nuclear Science and Engineering | Volume 17 | Number 1 | September 1963 | Pages 131-143
Technical Paper | doi.org/10.13182/NSE63-A17218
Articles are hosted by Taylor and Francis Online.
Integral experiments have been conducted to study rethermalization in moderating media having temperature discontinuities. Neutron absorption rates of Cu63, Au197, and Lu176 have been observed near these discontinuities in the temperatures of concentric annuli of graphite and of water and graphite systems. For this report the data have been analyzed with a two-thermal-group diffusion model of the space and energy distribution of the thermal neutrons. Cross sections and relaxation distances for neutron rethermalization in water and graphite have been inferred from the analyses. These rethermalization cross sections are integral representations of the scattering kernel. The relaxation distances were found to be shorter for the rethermalization of cold neutrons in warm graphite than for the rethermalization of warm neutrons in cold graphite. The cross section of hot graphite for rethermalization of 300°K neutrons increases monotonically to near the free gas value, 0.0614 cm−1, as the graphite temperature increases to 850°K. The cross section of 300°K graphite for rethermalization of 850°K neutrons is well below the free gas value, in agreement with theoretical calculations. Within the limits of the heavy gas model one can define an effective mass in terms of the rethermalization cross section. Effective masses of graphite reported here are comparable with those inferred by others from lattice-spectrum measurements. The rethermalization cross sections of 300°K water presented here yield effective masses of the water molecule that lie in the range of 4.1 to 7.2 amu for 410 to 720°K neutrons, respectively.
