A study of subcooled film-boiling heat transfer under reactivity-initiated accident conditions in light water reactors

The empirical correlations for subcooled film-boiling heat transfer during a reactivity initiated accident in light water reactors are derived from inverse heat conduction calculations using the cladding surface temperatures measured in in-reactor experiments. The experimental data for cold startup conditions (subcoolings of about 10 to 80 K and coolant velocities of about 0 to 2 m/s at atmospheric pressure) and hot standby conditions (subcooling of about 10 to 40 K, system pressures of 7.2 and 16 MPa, and system temperatures of 550 and 580 K) are used for this investigation. The present correlations are compared with existing correlations from ex-reactor experiments. The results of transient fuel behavior calculations with a computer code that included the present correlations are in good agreement with the corresponding measured data from the experiments.