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Fusion Science and Technology
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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
Donald R. Olander, Grant T. Fukuda, C. F. Baes, Jr.
Fusion Science and Technology | Volume 41 | Number 2 | March 2002 | Pages 141-150
Technical Paper | doi.org/10.13182/FST02-A208
Articles are hosted by Taylor and Francis Online.
The pressures of the vapor species in equilibrium with Flibe at ~600°C are determined from work by Buchler and Stauffer and by Baes and coworkers. The former authors show that the principal vapor species are BeF2(g) and LiBeF3(g). The measurements and the theoretical model of Baes provide accurate values of the activity coefficient of BeF2 in Flibe. When combined with the vapor pressure of pure BeF2, the equilibrium pressure of BeF2 is determined as a function of melt composition and temperature. The activity coefficient of LiF is not measured, but it is obtained by application of the Gibbs-Duhem equation to the measured activity coefficient of BeF2. Thus, the partial pressure of LiF(g) is also known. The pressure of the mixed dimer LiBeF3 is calculated from the gas phase equilibrium for the formation of the dimer from the two monomers, with the equilibrium constant given by Buchler and Stauffer. The vapor pressure at 600°C extrapolated from high-temperature Oak Ridge National Laboratory data is ~60% higher than the predicted values.
