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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
J.M. Miller, R.A. Verrall, D.S. MacDonald, S.R. Bokwa
Fusion Science and Technology | Volume 14 | Number 2 | September 1988 | Pages 649-656
Tritium Properties and Interactions with Material | Proceedings of the Third Topical Meeting on Tritium Technology in Fission, Fusion and Isotopic Applications (Toronto, Ontario, Canada, May 1-6, 1988) | doi.org/10.13182/FST88-A25208
Articles are hosted by Taylor and Francis Online.
Results from the CRITIC-I, vented capsule irradiation of Li2O are presented. A total lithium burnup of 0.74% has been achieved and 1500 curiesb of tritium have been collected over the first 15 months of irradiation. The temperature has been varied between 400 and 850°C, and the sweep gas composition changed progressively from pure He to He-1% H2. The amount of tritium recovered in the reduced form (HT) has increased from an initial value of approximately 50% with pure He sweep gas to a current value of 99% with He-1% H2. The increasing H2 concentration in the sweep gas has also reduced the time constants for tritium release (tritium residence time in the Li2O). Although the results indicate tritium release is controlled by surface desorption, simple first-order desorption theories do not explain all the observations. Most noticeably, for temperature increase tests, tritium release peak maxima can be delayed as long as 6 h and inventory changes depend not only on the initial temperature but also on the time at the initial temperature. An explanation is given based on the buildup of free oxygen in the ceramic from lithium burnup which leads to tritium trapping, perhaps as LiOH(T). Dissociation of LiOH(T) then occurs following an increase in the ceramic temperature, in addition to the simple first-order desorption process of isotopic exchange with H2 in the sweep gas.
