UPTF upper plenum injection (UPI) test results and application to PWR

The upper plenum test facility (UPTF) upper plenum injection (UPI) test provides data on upper plenum and loop phenomena related to loss of coolant accident (LOCA) reflood in a UPI plant. The UPTF is about 2.1 times larger than a pressurized water reactor with UPI. Data from Semiscale, Instrument Development Loop (IDL), Dartmouth, Cylindrical Core Test Facility (CCTF), Slab Core Test Facility (SCTF) and UPTF now cover UPI phenomena at a range of scale from 1/600 to 2.1 relative to a UPI plant. The UPTF test included subcooled emergency core coolant (ECC) injection into the upper plenum simultaneously with saturated steam/water flow from a simulated reactor core. There were three test phases, to parametrically study core steam flow and distribution. The UPTF results show major water delivery to the core in a very local region, rapid formation of an upper plenum pool, 100% condensation efficiency with 80% in the upper plenum and 20% in the core, and significant storage of carryover water in the hot legs. These phenomena show distinct trends with scale when compared to the results from scaled tests. Estimated UPI plant LOCA behavior is also determined from these comparisons. The inferred UPI plant behavior indicates that good core cooling is expected in the event of a large break LOCA