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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.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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Oklo to collaborate with Atomic Alchemy on isotope production
Fast reactor developer Oklo, which recently went public on the New York Stock Exchange, announced on May 13 that it has signed a memorandum of understanding with Atomic Alchemy to cooperate on the production of radioisotopes for medical, energy, industry, and science applications.
Paul Hurley, Connor Pigg, Yang Liu, Tomasz Kozlowski, Juliana Pacheco Duarte
Nuclear Technology | Volume 210 | Number 6 | June 2024 | Pages 1083-1096
Note | doi.org/10.1080/00295450.2023.2277005
Articles are hosted by Taylor and Francis Online.
Density wave oscillation (DWO) is one of the most extensively studied dynamic two-phase flow instabilities. The accurate prediction of these phenomena is important to ensuring safety in two-phase flow systems, such as boiling water reactors (BWRs). Recent reactor power uprates have led to the need for more accurate simulations at the system scale. For reactor licensing, the thermal-hydraulic computational code TRACE, developed by the U.S. Nuclear Regulatory Commission, is used for best-estimate predictions of light water reactors. One BWR power uprate condition of recent interest is the Maximum Extended Load Line Limit Analysis Plus, or MELLLA+, which allows BWRs to operate at lower core flow rates while maintaining the same power levels. Experiments performed at the Karlstein thermal-hydraulic test facility (KATHY) have shown that an anticipated transient without scram while operating under these conditions can lead to the development of DWOs.
This technical note assesses the capability of TRACE V5P7 to simulate DWO onset and development by comparison to the KATHY experimental data under natural circulation, focusing only on the thermal-hydraulic mechanisms. This study shows the analysis of DWO development from this data set, which utilized electrically heated fuel rods with a nonuniform axial power profile in a full-scale BWR rod bundle. The developed TRACE model is shown to be capable of producing DWO-type instability under the experimental conditions, while also allowing for an expanded parametric study on factors impacting stability.