Laser Doppler Anemometer Measurements of Local Fluid Recirculation in Model Rod Bundle Assemblies

摘要

Experimental studies have been performed at Pacific Northwest Laboratories to investigate the thermal-hydraulic characteristics of model rod-bundle assemblies subjected to conditions representative of certain postulated accident or emergency shutdown scenarios. Studies related to both light water and liquid metal cooled nuclear reactors have been conducted. The bulk of the experimental data gathered during these studies has been laser Doppler anemometer (LDA) measurements of fluid velocity distributions within rod bundle assemblies. The objectives of the various tests were to extend the useful data base for evaluating thermal-hydraulic computer codes used for safety related reactor analysis. Of particular interest has been the ability of the LDA to detect and quantify areas of local fluid recirculation, such as have been found immediately downstream of simulated fuel ballooning blockages and in zones of large differential buoyancy forces for heated rod bundles operated with severe radial power skews. The non-intrusive nature of the LDA technique is considered important for such measurements of induced countercurrent flow. (ERA citation 07:050461)