They can determine the point at which highly efficient boiling heat transfer begins to deteriorate. When the onset of transition boiling is detected by one of the thermocouples, the data acquisition system is activated. For plant owners, this can be translated into precise operating limits for the purpose of maximizing fuel cycle efficiency and operating flexibility. Based on temperature measurements of electrically heated, simulated fuel, GE has qualified computer codes to predict fuel temperatures during a hypothetical LOCA event. The facility permits the study of vessel blowdown, fluid flow and ECCS heat transfer interaction.
Loss of coolant is initiated by actuating a quick-opening valve.
During the blowdown, power to the bundle is decayed to simulate a plant scram. Measurements of the resulting system response include rod surface temperatures, system pressure and temperatures and system flow rates. Results Measurements of system response and bundle heat-up response under a simulated BWR design basis accident are compared with NRC licensing code predictions. Comparisons of predicted versus measured results indicate substantial margin in the prediction of BWR post-LOCA peak cladding temperatures. The effects of a pressurized steam environment on spray distribution from a single core spray nozzle are measured in this facility.