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.
Division Spotlight
Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
Apoorva Rudra, Masahiro Kawaji (City College of New York), Aleksandr V. Obabko Saumil Patel (ANL)
Proceedings | Advances in Thermal Hydraulics 2018 | Orlando, FL, November 11-15, 2018 | Pages 694-700
Very High Temperature Reactors (VHTRs) have passive safety systems in comparison to the traditional current generation nuclear reactors that have active safety systems. In addition, they have gaseous coolants like helium proposed for them that allow them to operate at a temperature over 1000 oC along with other applications. However, several substantial engineering challenges are expected in VHTRs and can lead to localized hot spots in the reactor core as a result of degraded heat transfer in coolant channels. Our work addresses one such scenario called flow relaminarization. The following work incorporates 3D simulations in a very long pipe wherein turbulence is sustained throughout for the largest aspect ratio (L/D ratio) known in literature (~235). This work is the first step of a two-step process towards the final objective of studying heat driven turbulent gas relaminarization. Simulations are performed using a high order, spectral element and massively parallel CFD code called NEK5000 that combines the geometric flexibility of finite elements with the high accuracy of spectral methods. A replication method along with recycled periodicity is incorporated to successfully sustain turbulence throughout the pipe. The maximum Reynolds number incorporated for these simulations is 5190 which is chosen keeping in mind the flow relaminarization (forced convection) experiments that were performed by the group in the past. A sensitivity study on the polynomial order was performed as well and based on that the polynomial order chosen for the simulations was 6.