EXPERIMENTAL ANALYSIS OF THE VELOCITY FIELD IN AN ANNULAR CHANNEL WITH HELICOIDAL WIRE.

Abstract

In general, nuclear reactor fuel elements are rod bundles with coolant flowing axially among them. LMFBR's (Liquid Metal Fast Breeder Reactor) have wire wrapped fuel rods, with the wire working as spacer and mixer. The present work consists in the experimental analysis of the velocity field created by a typical LMFBR fuel rod placed in a cylinder, yielding an annular channel with helicoidal wire. Using hot-wire anemometry, the main and secondary velocity fields were measured. The range for Re was from 2. 2 multiplied by 10**4 to 6. 1 multiplied by 10**4, for air. The aspect ratio, P/D, and the lead-to-diameter ratio, l/D, were 1. 2 and 15, respectively. For further experimental work it is suggested that the measurement of the full field in a bundle and comparisons with vector composition be mentioned. The results can lead to improvements in LMFBR fuel assemblies design.