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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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2025 ANS Annual Conference
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Chicago, IL|Chicago Marriott Downtown
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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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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
Bradley Heath, Colby Jensen
Nuclear Technology | Volume 206 | Number 9 | September 2020 | Pages 1436-1448
Technical Paper | doi.org/10.1080/00295450.2020.1725370
Articles are hosted by Taylor and Francis Online.
The Transient Reactor Test (TREAT) Facility is a graphite reactor capable of delivering tailored power histories to unique experiment designs. Frequently, these experiments are designed to simulate a specific reactor transient to perform detailed studies of reactor fuel behavior. The reactor core is uniquely designed to allow a limited energy release and resulting peak fuel cladding temperature such that thermal feedback mechanisms shut the reactor power transient down in a passive manner, thus maximizing the lifetime of the reactor fuel cladding. The reactor is air cooled; however, the cooling system does not serve a safety function. The air cooling is typically used for four main functions: (1) accelerate cooling of the reactor core to ambient temperature post transient operations, (2) remove activated gases from the reactor cavity, (3) perform heat balance for power calibration, and (4) maintain criticality on extended steady-state runs or shaped transients. With the restart of the reactor, these systems are now fully operational and have been exercised during the past year for the first time in more than 20 years. This paper summarizes the thermal properties of the core and the thermal-hydraulic design of the TREAT Facility and presents selected results of temperature profiles resulting from operation. Conservatively estimated maximum transient energy and steady-state power is provided.