He jishu (Jul 2023)
Sedimentation movement of particles in liquid lead-bismuth alloy reactor core channel based on grey correlation degree
Abstract
BackgroundIn the international fourth-generation nuclear power system, the lead-bismuth fast reactor is one of the most concerned technologies. However, insoluble particulate matter generated in the flow of liquid lead-bismuth alloys will collect locally in the flow channel and affect the operation of lead-bismuth fast reactors.PurposeThis study aims to find the motion deposition of particulate matter in the flow channel, understand its influence on the safe operation of small lead-bismuth fast reactors, and provide a reference for the safe design of lead-bismuth reactors.MethodsFirstly, based on the design scheme of 100 MWth small natural circulation lead cooled fast reactor SNCLFR-100, the particle deposition in the rod bundle channels that were divided into three types according to the relative position and wall conditions: triangle like channels, pentagon like channels and trapezoid like channels, was numerically simulated using ANSYS software, and the particle deposition movement was obtained. Then, the effects of particle type, particle size and particle velocity on particle deposition were obtained on the basis of grey correlation degree theory. Finally, the correlation degree of various factors affecting particle deposition rate was analyzed.ResultsThe results show that the particle deposition mainly occurs at the inlet stage,the surface of the inlet section is large area adhesion deposition,and the surface of the middle and rear sections is point-like deposition. With the increase of axial distance, the magnitude of turbulent kinetic energy is the main factor affecting the radial distribution of particulate matter. The increase of particle density and particle size will strengthen the deposition of particulate matter. The increase of particle velocity will reduce the particle deposition. The degree of influence on particle deposition is particle size>type> particle velocity.ConclusionsDuring the operation of lead-bismuth fast reactor, attention should be paid to the deposition of particles in the inlet section and to remove the particles with larger particle size.
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