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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
Marie-Charlotte Gauffre, Sofiane Benhamadouche, Pierre-Bernard Badel
Nuclear Technology | Volume 206 | Number 2 | February 2020 | Pages 255-265
Technical Paper | doi.org/10.1080/00295450.2019.1642684
Articles are hosted by Taylor and Francis Online.
The EDF aims to identify what causes fuel assembly vibrations in pressurized water reactors. The present work focuses on the validation of pressure fluctuations along the central rod of a 5 × 5 configuration for wall-modeled large eddy simulations. New experiments, called CALIFS, have been carried out by the Atomic Energy Commission (CEA) on a 5 × 5 mixing vane grid (MVG) in the framework of the Fuel Assembly EDF/CEA/FRAMATOME tripartite project. In addition to pressure drop and velocity measurements using particle image velocimetry, pressure measurements have been performed along the central rod. The computational domain is representative of a span of the experimental mock-up composed of a 5 × 5 rod bundle equipped with a split-type MVG. The hydraulic Reynolds number is equal to 66 000 and periodic boundary conditions are imposed in the streamwise direction. The mesh is fully hexahedral and conformal. Computations give very satisfactory results for the pressure drop, the mean velocity, and the Reynolds stresses at different locations. The root-mean-square of the pressure along the central rod is also compared to experimental data at different heights. The behavior is in very good agreement up to five hydraulic diameters downstream of the MVG.