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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.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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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Latest News
ARG-US Remote Monitoring Systems: Use Cases and Applications in Nuclear Facilities and During Transportation
As highlighted in the Spring 2024 issue of Radwaste Solutions, researchers at the Department of Energy’s Argonne National Laboratory are developing and deploying ARG-US—meaning “Watchful Guardian”—remote monitoring systems technologies to enhance the safety, security, and safeguards (3S) of packages of nuclear and other radioactive material during storage, transportation, and disposal.
M. M. R. Williams
Nuclear Science and Engineering | Volume 197 | Number 1 | January 2023 | Pages 104-131
Technical Paper | doi.org/10.1080/00295639.2022.2103336
Articles are hosted by Taylor and Francis Online.
We describe the manner and rate at which water infiltrates and/or transpires into a drum of dry uranium dioxide powder. The powder is 5% enriched and so the possibility of a critical state is possible. In view of the porous nature of the powder, it will exhibit all the characteristics of soil and hence the motion of the water will be described by the use of the methods developed over many years in the field of soil science. The basic phenomena of flow in porous media are described by Richards’ equation, which leads to the moisture concentration from which we may obtain the local density of water. This, together with the fissile cross section of the powder, will enable us to calculate the multiplication rate of the neutron population. The neutron source term arises naturally from spontaneous fission and various reactions. Several scenarios are described, but the two most important cases are (1) when water enters the drum from the top and infiltrates downward, and (2) when water leaks in from the base and capillary forces draw the water upward. Both situations can occur simultaneously depending on the damage sustained by the drum. By damage we do not necessarily mean mechanical due to impact, but also by corrosion if the drum is left unattended in a damp environment. With the space and time dependence of the water concentration available, we can solve the corresponding transport or diffusion equations for the neutron flux and hence calculate the energy produced. In this introductory paper, we do not include feedback, and so in principle, when the water reaches the boiling point our calculations must cease. However, the crucial point is whether criticality will occur, and this can be decided by the value of the multiplication factor . We use the Broadbridge and White model for the porous medium and consider the influence of the porous structure on the value of . A range of examples is considered both with infiltration and transpiration, and it is shown that the likelihood of criticality is high although less likely for transpiration.
