Flow near end plates in CANDU-type 19 rod fuel bundle

Two methods have been employed to investigate the flow near a set of end plates in CANDU-type 19 rod fuel bundle: 1. velocity distributions of peripheral subchannels at five levels are measured by Laser Doppler Anemometry; the five levels include three levels before and two levels behind the end plates; 2. flow patterns of dye in peripheral subchannels are photographed at 1/1000 s shutter speed, while the dye is injected into an interior subchannel and spreads to adjacent subchannels. Results indicate that end plates do disturb the flow - they promote strong mixing and redistribute subchannel flow before and behind the end plates. Conventional subchannel analysis will provide subchannel flow rate within 20% error, and the photos show little chance of reaching the fully developed state for subchannel flow. © 1982.