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Materials Science & Technology
The objectives of MSTD are: promote the advancement of materials science in Nuclear Science Technology; support the multidisciplines which constitute it; encourage research by providing a forum for the presentation, exchange, and documentation of relevant information; promote the interaction and communication among its members; and recognize and reward its members for significant contributions to the field of materials science in nuclear technology.
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2025 ANS Annual Conference
June 15–18, 2025
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
T. Cutler, H. Trellue, M. Blood, T. Grove, E. Luther, N. Thompson, N. Wynne
Nuclear Technology | Volume 209 | Number 1 | January 2023 | Pages S92-S108
Technical Paper | doi.org/10.1080/00295450.2022.2027146
Articles are hosted by Taylor and Francis Online.
The Hypatia measurement campaign with YHx moderators and highly enriched uranium (HEU) was completed in January 2021 at the U.S. Department of Energy’s National Criticality Experiments Research Center at the Nevada National Security Site. This measurement campaign provided unique integral measurements based on two experimental configurations and investigated the temperature effects of yttrium hydride (YHX = 1.8 and 1.9) in a critical reactor system, which is of potential interest for microreactor designs. The Hypatia experiment consisted of a fuel column composed of HEU, 93 wt% 235U discs, encapsulated YHX, aluminum oxide heater plates, and other moderator and reflector materials (beryllium, depleted uranium, and graphite) inserted into a thick beryllium reflector. During the Hypatia experiment, baseline measurements were taken at room temperature. The aluminum oxide heater plates were specially designed and used for this project to increase the central core temperature to a range of temperatures, after which additional reactivity measurements were taken. Thermal and neutronic calculations predicted that YHX is a unique material that can exhibit a positive temperature coefficient of reactivity (i.e., reactivity can increase as the temperature in the YHX increases). Reactors using YHX should account for this unique feature during design, and the results of the Hypatia experiment significantly aid that process. For configuration 1, six different temperature reactivity measurements were taken with four YHX cans in the fuel column. For configuration 2, six different temperature reactivity measurements were taken with two YHX cans in the fuel column. The use of these two configurations provide a comparison of neutronic effects from the YHX cans versus other components. Preliminary conclusions show the positive temperature coefficient is similar but slightly less than predicted by simulations. These two sets of data will be used to separate the reactivity coefficients of the fuel and other materials in the fuel column.
