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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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Latest News
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.
Young Min Kim, Moon Sung Cho
Nuclear Technology | Volume 170 | Number 1 | April 2010 | Pages 231-243
Technical Paper | Special Issue on the 2008 International Congress on Advances in Nuclear Power Plants / Fuel Cycle and Management | doi.org/10.13182/NT10-A9461
Articles are hosted by Taylor and Francis Online.
The COPA-FPREL computer code has been developed to estimate the releases of gaseous and metallic fission products (FPs) from high-temperature gas-cooled reactor (HTGR) fuel into coolant. The COPA-FPREL code treats FP release from a coated fuel particle (CFP), diffusion in a fuel element, and leakage into the coolant considering the temperature distribution within a CFP and a fuel element. The code uses a finite difference method to calculate FP migration and heat transfer. In the finite difference method, the kernel, buffer, and coating layers of a CFP and the fuel element are divided into small finite difference intervals. A steady-state heat transfer equation and the Fickian diffusion equation are applied to these intervals. A relatively high diffusion coefficient is assigned to the buffer and the broken coating layers to describe fast diffusion in those regions. Sorption equilibrium is set up between the concentration at the fuel element surface facing the coolant and the vapor pressure at the graphite side of the boundary layer that forms on the fuel element surface. Mass transfer occurs through the boundary layer into the bulk coolant. In a prismatic HTGR, sorption equilibrium is assumed to form between the concentrations at the compact and structural graphite surfaces and the vapor pressure in the gap between the compact and the structural graphite. For 137Cs, 90Sr, 110mAg, and 85Kr isotopes, the fractional releases from a CFP, a pebble, and a fuel block during simulated heating processes and reactor operations were calculated using COPA-FPREL.
