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
Aerospace Nuclear Science & Technology
Organized to promote the advancement of knowledge in the use of nuclear science and technologies in the aerospace application. Specialized nuclear-based technologies and applications are needed to advance the state-of-the-art in aerospace design, engineering and operations to explore planetary bodies in our solar system and beyond, plus enhance the safety of air travel, especially high speed air travel. Areas of interest will include but are not limited to the creation of nuclear-based power and propulsion systems, multifunctional materials to protect humans and electronic components from atmospheric, space, and nuclear power system radiation, human factor strategies for the safety and reliable operation of nuclear power and propulsion plants by non-specialized personnel and more.
Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
Jun 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
July 2025
Fusion Science and Technology
Latest News
NRC cuts fees by 50 percent for advanced reactor applicants
The Nuclear Regulatory Commission has announced it has amended regulations for the licensing, inspection, special projects, and annual fees it will charge applicants and licensees for fiscal year 2025.
Rahman S. Almusafir, Ahmed A. Jasim, Muthanna H. Al-Dahhan
Nuclear Science and Engineering | Volume 197 | Number 6 | June 2023 | Pages 1001-1037
Critical Review | doi.org/10.1080/00295639.2022.2146993
Articles are hosted by Taylor and Francis Online.
Knowledge and proper safety analyses of the gas coolant and heat transport mechanism in the dynamic core of packed pebble bed nuclear reactors pose challenges to the reliable design and efficient operation of these reactors. Therefore, this paper carefully reviews most of the gas coolant mixing and heat transport studies performed for the fluid flow and heat transfer processes in packed pebble bed reactors (PBRs). It begins with a brief introduction and description of nuclear PBRs. The second section summarizes the physical characteristics of packed bed reactors in terms of the bed structure (porosity) and its radial and axial distributions. The next section examines in detail the characteristics of fluid flow in terms of flow regime identification and pressure drop measurements and correlations. The fourth section considers the investigations and quantifications of the gas dispersion and mixing phenomena of packed bed reactors. The next section deals with the current state of the heat transfer characteristics, measurements, and predictions including both empirical correlations and semiempirical model-based studies. Tables summarize the reported experimental studies along with their operating condition ranges. Comprehensive comparisons with the empirical correlations and available models are presented with significant findings. The content and findings of the present work could provide a thorough understanding and useful information and advance knowledge of the pressure drop, gas coolant mixing, and convective heat transport phenomena in packed pebble bed nuclear reactors.