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The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
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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
Tao Liu, Yuan Zhou, Mingjun Zhong, Houjun Gong
Nuclear Science and Engineering | Volume 197 | Number 3 | March 2023 | Pages 398-412
Technical Paper | doi.org/10.1080/00295639.2022.2116379
Articles are hosted by Taylor and Francis Online.
In a reactor severe accident, molten jet breakup and solidification are important behaviors after large pours of molten material fall into the coolant in-vessel or ex-vessel. However, heat and mass transfer processes inside melt during jet breakup have not been studied sufficiently. Existing research on jet fragmentation is relatively macroscopic, and the micro interface condensation details are not well studied. In this paper, a two-dimensional multiphase computational fluid dynamics (CFD) code with the Volume of Fluid (VOF) method and solidification model is applied to simulate molten jet breakup with surface solidification. The VOF model is used to capture the interface, study the details, and add the influence of solidification. Solidification and instability can be seen at the interface. In order to simulate melt solidification, an energy equation is modeled using an enthalpy-based formulation, and viscosity variation during phase change is taken into account. The comparative results between the CFD code and jet breakup experiments show that melt jet front position histories, breakup length, and breakup time are in good agreement with the experiments. The simulation results show that crust formation of the jet surface suppresses surface instability and jet breakup behavior. As the interfacial temperature decreases, the droplet cumulative mass fraction decreases, and the solidified metal proportion increases. The simulation results by the CFD code with the solidification model are valuable and important for understanding the molten jet breakup mechanism.