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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.
Yassin A. Hassan, Hagop R. Barsamian
Nuclear Technology | Volume 128 | Number 1 | October 1999 | Pages 58-74
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT99-A3014
Articles are hosted by Taylor and Francis Online.
The dynamic subgrid-scale (DSGS) closure model is used in a large eddy simulation computer program for incompressible isothermal flows. One of the advantages of the DSGS model is the exclusion of a model coefficient. This model coefficient is evaluated dynamically at each nodal location for a given time step by filtering operations on the grid level and a test filter level. A nonstaggered array tube bundle geometry arrangement is considered in doubly periodic boundary conditions for two-dimensional simulations at high Reynolds number. Results of the DSGS simulation are obtained in the form of power spectral densities and visualization of flow characteristics. The DSGS model simulation results are compared to the Smagorinsky eddy viscosity model simulation and available experimental data. The DSGS model simulation is found to be in good agreement with spectral data available from experiments in similar bundle arrangements. Coherent eddy structures were observed. Body forces acting on the tubes showed satisfactory characteristics. Integral length and timescales are evaluated using correlation functions that describe the turbulence structure. The applicability of large eddy simulation to complex engineering flow situations has been shown using the DSGS model with applications to steam generator bundles for understanding of flow-induced vibration problems revealing the physical phenomena of the flow.
