ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
Standards Program
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!
Latest Magazine Issues
Sep 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
Fusion Science and Technology
October 2025
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.
Sriram Chandrasekaran, Srinivas Garimella
Nuclear Technology | Volume 206 | Number 11 | November 2020 | Pages 1698-1720
Technical Paper | doi.org/10.1080/00295450.2020.1750274
Articles are hosted by Taylor and Francis Online.
A whole-core, steady-state, thermal-hydraulic model for the cylindrical pin-type fluoride-salt-cooled small modular advanced high-temperature reactor (SmAHTR) is developed. In this preconceptual reactor design initially proposed by Oak Ridge National Laboratory, each fuel assembly in the graphite-moderated core has the FLiBe coolant flowing parallel to a hexagonal array of fuel and moderator pins. The present study considers a slightly modified fuel assembly design with a hexagonal inner housing compared to the original cylindrical housing. Burnable poison pins and control rods are also included in the fuel assembly considered here. The thermal-hydraulic model employs finite volumes to solve three-dimensional conduction in the pins and the hexagonal graphite reflector regions in the core. Heat transfer between the fuel assemblies is also addressed. The finite volumes in the fluid region are modeled using a subchannel approach in which the fluid is discretized into edge, corner, and interior subchannels and the resulting mass, momentum, and energy equations are systematically solved. The subchannel model also includes the transport between adjacent subchannels both due to radial pressure gradient–driven cross flow and turbulent mixing. Appropriate closure models from the literature are used to quantify axial and lateral flow resistances, heat transfer from solid to fluid, and turbulent mixing. The resulting thermal-hydraulic model provides detailed temperature and flow information for the entire core at a modest computational cost. Preliminary verification studies are also performed and reported.
Whole-core, steady-state results are presented for this SmAHTR core configuration for different power profiles. The effect of grid refinement and total mass flow rate into the core on the peak fuel temperature is also investigated. Fuel temperatures from a preliminary analysis with pin power distributions from a neutronic model are also included. The peak fuel temperature of ~1229°C in this illustrative case is below the steady-state operation limit for the SmAHTR.
