Effect of the operating conditions on the behavior of the flow outgoing the core of a SFR reactor

• Published in: Nuclear engineering and design Vol. 393; p. 111797
• Main Authors: Guenadou, D., Aubert, P., Descamps, J.-P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2022; Elsevier BV
• Subjects: Buoyancy; Experiment; Flow rates; PIV; Reactors; Sodium; Thermal fatigue; Velocity; Sodium; PIV; Experiment; Buoyancy
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2022.111797

•Flow fluctuations lead to thermal fatigue and reactor lifetime decrease.•Oscillations occur when the jet coming from the core rises.•Velocity measurements allow to evaluate the rising conditions.•The use of the Richardson enables to transpose the results to higher scales. Since decades, the CEA is involved in the development of 4th generation reactors cooled by sodium. As experiments with sodium are complex, the tests are mostly led using water as a simulant fluid. The MICAS mock-up, model of the upper plenum, aims at studying the behavior of the jet outgoing from the core. At low operating power, the jet may rise and oscillate, leading to thermal fatigue on the immerged components. Knowing the operating conditions range for which the jet is steady is a key for designing the hot plenum. The jet behavior is investigated at different operating conditions using velocity measurements performed by the Particle Imaging Velocity technique. The jet core is determined by applying a longpass filter based on a ratio of the maximum velocity. The orientation of the jet is analyzed using two methods, one based on the velocity and the other one on the shape of the core jet. They give non-consistent results, the one based on the velocity giving the core flowrate highest value for the onset of the rise of the jet.