Single Phase Pressure-Drop Tests in 7-Element Bundles With Different Endplug Shapes

Pressure-drop characteristics in CANDU^® fuel bundles are of importance for critical power analysis and safety trip analysis for the reactor core. Different kinds of endplug shapes are being used in different fuel designs. The difference in endplug shape may result in slightly different hydraulic characteristics of the fuel bundles. Single-phase pressure-drop tests were performed in aligned and misaligned (15° and 30°) 7-element bundle strings with three different endplug shapes (Type 1, 2 and 3): Type 1 and 3 with round surface, and Type 2 with flat surface. The test results showed that the bundle-loss coefficients of the misaligned bundle with Type 2 having flat surface presented the highest value among the three-endplug types: 8.6% higher on average, compared to those of the misaligned bundle with Type 1 endplugs (Type 1 as a reference).