Jet-plume condensation of steam-air mixtures in subcooled water, Part 1: Experiments

A scaled-down, reduced pressure suppression pool was designed to study condensation and mixing phenomena for a LOCA (loss of coolant accident) event in a SBWR (simplified boiling water reactor) design. The scaled-down test facility represented an idealized trapezoidal cross-section, 1/10 sector of the SP (suppression pool) with scaled height ratio of 1/4.5 and volume ratio of 1/400. The facility was instrumented with thermocouples for pool temperature measurements and a high-speed camera for flow visualization. Thermal stratification data were obtained for different pool initial subcooling and steam-air mixture flow rates. A dimensionless boundary map was derived from several experimental runs of pure steam injection to determine conditions when the pool transitions from being a homogeneously mixed volume to being a thermally stratified one. Steam air mixture injection cases for single horizontal venting indicated that above a pool temperature of 40 deg. C with air mass fraction below 0.5% the pool can attain thermal stratification.