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
2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
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
May 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
July 2025
Nuclear Technology
June 2025
Fusion Science and Technology
Latest News
High-temperature plumbing and advanced reactors
The use of nuclear fission power and its role in impacting climate change is hotly debated. Fission advocates argue that short-term solutions would involve the rapid deployment of Gen III+ nuclear reactors, like Vogtle-3 and -4, while long-term climate change impact would rely on the creation and implementation of Gen IV reactors, “inherently safe” reactors that use passive laws of physics and chemistry rather than active controls such as valves and pumps to operate safely. While Gen IV reactors vary in many ways, one thing unites nearly all of them: the use of exotic, high-temperature coolants. These fluids, like molten salts and liquid metals, can enable reactor engineers to design much safer nuclear reactors—ultimately because the boiling point of each fluid is extremely high. Fluids that remain liquid over large temperature ranges can provide good heat transfer through many demanding conditions, all with minimal pressurization. Although the most apparent use for these fluids is advanced fission power, they have the potential to be applied to other power generation sources such as fusion, thermal storage, solar, or high-temperature process heat.1–3
Atsuhiko Terada, Ryuji Nagaishi
Nuclear Science and Engineering | Volume 197 | Number 4 | April 2023 | Pages 647-659
Technical Paper | doi.org/10.1080/00295639.2022.2126689
Articles are hosted by Taylor and Francis Online.
To understand the dispersion of hydrogen (H2) leaked in a partially open space practically, which can be considered as a basic model for all processes of transfer, treatment, storage, and disposal of radioactive materials containing fuel debris in the decommissioning of nuclear facilities after a severe accident, this paper uses a computational fluid dynamics code to study analytically the effects of vent size and outer wind on H2 dispersion. The paper adopts the experimental Hallway model, which has a H2 release hole on the ceiling, one vent on the roof (Roof vent), and one vent on the side (Door vent). Air flows in the model (room) from the Door vent while H2 is discharged outside from the Roof vent. The discharged (outflow) amount of H2 increases in conjunction with the air inflow when the size of the Roof and/or Door vents is increased, and then vice versa. The effect of wind depends on the direction to the Door vent: Wind from the same direction as the Door vent promotes H2 discharge while wind from the opposite direction suppresses it. The dispersion behavior characteristics of indoor leaked H2 are clarified for comparing model tests with the same Froude number and different scales. It is found from the analysis results of comparing model tests with the same Froude number and different scales that when H2 leaks into the room and diffuses to the air, the flow generated by the buoyancy of mixed gas creates the stack effect, which causes natural ventilation by drawing in air from the outside through the vent. In addition, it is speculated that the H2 concentration decreases after its leak by quickly mixing with air that flows in from the vents and reaches the floor due to the Coanda effect, which is the effect of the free jet being drawn to a nearby wall.