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 8–12, 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
Oct 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
December 2025
Nuclear Technology
November 2025
Fusion Science and Technology
Latest News
DNFSB’s Summers ends board tenure, extending agency’s loss of quorum
Lee
Summers
The Defense Nuclear Facilities Safety Board, the independent agency responsible for ensuring that Department of Energy facilities are protective of public health and safety, announced that the board’s acting chairman, Thomas Summers, has concluded his service with the agency, having completed his second term as a board member on October 18.
Summers’ departure leaves Patricia Lee, who joined the DNFSB after being confirmed by the Senate in July 2024, as the board’s only remaining member and acting chair. Lee’s DNFSB board term ends in October 2027.
Elia Merzari, Haomin Yuan, Misun Min, Dillon Shaver, Ronald Rahaman, Patrick Shriwise, Paul Romano, Alberto Talamo, Yu-Hsiang Lan, Derek Gaston, Richard Martineau, Paul Fischer, Yassin Hassan
Nuclear Technology | Volume 207 | Number 7 | July 2021 | Pages 1118-1141
Technical Paper | doi.org/10.1080/00295450.2020.1824471
Articles are hosted by Taylor and Francis Online.
This paper demonstrates a multiphysics solver for pebble-bed reactors, in particular, for Berkeley’s pebble-bed -fluoride-salt-cooled high-temperature reactor (PB-FHR) (Mark I design). The FHR is a class of advanced nuclear reactors that combines the robust coated particle fuel form from high-temperature gas-cooled reactors, the direct reactor auxiliary cooling system passive decay removal of liquid-metal fast reactors, and the transparent, high-volumetric heat capacitance liquid-fluoride salt working fluids (e.g., FLiBe) from molten salt reactors. This fuel and coolant combination enables FHRs to operate in a high-temperature, low-pressure design space that has beneficial safety and economic implications. The PB-FHR relies on a pebble-bed approach, and pebble-bed reactors are, in a sense, the poster child for multiscale analysis.
Relying heavily on the MultiApp capability of the Multiphysics Object-Oriented Simulation Environment (MOOSE), we have developed Cardinal, a new platform for lower-length-scale simulation of pebble-bed cores. The lower-length-scale simulator comprises three physics: neutronics (OpenMC), thermal fluids (Nek5000/NekRS), and fuel performance (BISON). Cardinal tightly couples all three physics and leverages advances in MOOSE, such as the MultiApp system and the concept of MOOSE-wrapped applications. Moreover, Cardinal can utilize graphics processing units for accelerating solutions. In this paper, we discuss the development of Cardinal and the verification and validation and demonstration simulations.