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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.
Robert E. Spears, Efe G. Kurt, Justin L. Coleman
Nuclear Technology | Volume 205 | Number 4 | April 2019 | Pages 624-636
Technical Note | doi.org/10.1080/00295450.2018.1507393
Articles are hosted by Taylor and Francis Online.
Seismic soil-structure interaction (SSI) analysis of nuclear facilities is an important consideration during design and retrofit. SSI tools used in the nuclear industry are currently based on an equivalent linear (EL) approach. Procedures for developing input ground motion for EL approaches are well established. However, the procedures for establishing input ground motion for nonlinear soil-structure interaction (NLSSI) analysis of nuclear facilities are not well established. A collaborative research group at Idaho National Laboratory has recently developed analytical methods and numerical tools for using NLSSI analysis for nuclear facility seismic calculations. NLSSI analysis for a nuclear facility allows for calculation of seismic wave motion through a near-field soil domain using either (a) vertically propagating shear and compressive waves, which is the current industry practice, or (b) a three-dimensional nonvertical wave field. This technical note presents an iterative procedure for establishing outcrop motion at a depth in the soil column for NLSSI analysis that uses vertically propagating shear waves.
The approach presented in this technical note starts with a known ground motion at the surface that is deconvolved to a depth, and then the obtained motion is convolved up to a different desired location of input for the NLSSI model. To demonstrate the validity of the approach, a finite element soil column that is representative of a nuclear facility site in the United States is used to produce compatible outcrop seismic time series for reduced nonlinear soil mesh depths. The developed approach for reducing the nonlinear soil column model depth is a two-step iterative method. The first step is establishing an outcrop time series at the lowest depth considered that produces the top-of-soil response spectrum of an actual recorded ground motion. The second step is providing compatible outcrop time series at a shallower depth based on the information from the first step.
A comparison of the 5% damped response spectrum from the resulting acceleration time series based on the iterated outcrop motions and the original acceleration time series is conducted. The study shows that the proposed iterative approach produced comparable results within 1% range of the original recorded time series results when sufficient iterations were performed.
