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
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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!
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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
Thomas M. Sutton
Nuclear Science and Engineering | Volume 197 | Number 2 | February 2023 | Pages 164-175
Technical Paper | doi.org/10.1080/00295639.2022.2065872
Articles are hosted by Taylor and Francis Online.
The results of neutron Monte Carlo (MC) transport calculations are subject to random fluctuations about their expected values. The term “neutron clustering” refers to situations in which these fluctuations exhibit particularly strong spatial correlations in iterated-fission-source calculations. Various idealized models of the MC process have been developed to study this phenomenon. Over time, these models have evolved to more realistically reflect the algorithms used in MC codes. This paper continues along this path by including the possibility that some neutrons will not terminate in an event that can potentially produce new neutrons and by considering an algorithm without replacement (WOR) for selecting the neutron source sites. It is shown that sampling source sites WOR versus with replacement can greatly reduce the degree of clustering.
