ORNL PWR Blowdown Heat Transfer Program

The PWR-Blowdown Heat Transfer Program is an experimental, separate effects, study of the relations among the principal variables that can alter the rate of blowdown, the presence of flow reversal and re-reversal, and time delay to critical heat flux, the rate at which dryout progresses, and similar time- related functions that are important to LOCA analysis. Primary test results will be obtained from the Thermal Hydraulic Test Facility (THTF), a large, non-nuclear pressurized-water loop which incorporates a 49-pin electrically heated bundle. Ancillary experiments are carried out in two additional test loops--the Forced Convection Test Facility (FCTF), a small, high-pressure facility in which single heater pins can be tested in annular geometry, and an air-water loop which is used to evaluate two-phase flow-measuring instrumentation. (auth