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2025 ANS Annual Conference
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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
Pan Wu, David Novog
Nuclear Technology | Volume 205 | Number 1 | January-February 2019 | Pages 364-376
Technical Paper | doi.org/10.1080/00295450.2018.1495000
Articles are hosted by Taylor and Francis Online.
The CTF code is a subchannel thermal-hydraulic code developed based on the COBRA-TF code. In this work, the CTF code is used to predict the single- and two-phase heat transfer, pressure drop, onset of nucleate boiling, and dryout heat flux in water at several temperatures and pressures under steady-state and transient conditions. The conditions cover a range of pressures from 2 to 6 MPa, flows from 1000 to 2500 kg/(m2∙s), and inlet subcooling from 40°C to 70°C. Experimental heat balance tests show agreement between coolant enthalpy change and the electrical power with a difference of no more than 1.0%. Steady-state experiments were performed at constant inlet conditions in a cylindrical directly heated Inconel test section where the wall temperatures were measured at each power level. For each steady-state test, the experimental boiling curve is compared to CTF predictions. Transient experiments were performed by initiating a blowdown from the test section outlet plenum using a fast-acting valve with an open time of less than 100 ms. The time of dryout in these transient experiments is compared with the CTF results to clarify the pressure transient effect on the dryout prediction.