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
IAEA report confirms safety of discharged Fukushima water
An International Atomic Energy Agency task force has confirmed that the discharge of treated water from Japan’s Fukushima Daiichi nuclear power plant is proceeding in line with international safety standards. The task force’s findings were published in the agency’s fourth report since Tokyo Electric Power Company began discharging Fukushima’s treated and diluted water in August 2023.
More information can be found on the IAEA’s Fukushima Daiichi ALPS Treated Water Discharge web page.
Jarod Wilson, Sara Hauptman, Akshay Dave, Kaichao Sun, Lin-wen Hu (MIT), Ruimin Ji, Yang Zou (CAS)
Proceedings | 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) | Charlotte, NC, April 8-11, 2018 | Pages 76-83
The growing global demand for emission-free energy is creating a market for advanced Generation-IV NPP, and the Fluoride salt-cooled High-temperature Reactor design with a pebble-type fuel is a promising candidate. However, this design also brings unique challenges, namely evaluating the effects of the fuel’s distribution and dynamic movement. Generating explicitly described fuel pebble loading patterns is non-trivial. This study serves two main purposes: 1) to investigate the neutronic performance of pebble type fuel within the TMSR-SF1, and 2) to conduct a preliminary comparison between pebble coordinate generation methods. The first method of coordinate generation, the Discrete Element Method (DEM), is a particle-tracking model which accounts for inter-particle forces. While this method generates packing distributions closer to real-world scenarios, it is computationally intense. The alternative method analyzed is a mathematical model (MM), which fills arbitrary domains through simple geometric rules on the addition of particles. This method, while less realistic, generates coordinates significantly faster. Afterwards, fuel pebble coordinates from both methods are utilized to generate inputs for high-fidelity neutronics modelling. The results of these simulations, with the aid of various tools within Python, allowed for the neutronic analysis of the core, specifically when considering the eigenvalues of each coordinate set, and the fission power distribution within the fuel pebbles. It was found that the packing fraction in the axial direction to be consistent within the MM coordinate generation method, and the general trends similar between it and DEM-generated coordinates. Additionally, the eigenvalues of the simulated core were found to be proportional to the number of pebbles within the core. Finally, the fission power distribution of the cores was found to be qualitatively consistent both within many sets of MM-generated coordinates, and in comparisons of the two coordinate generation methods.