Critical flow of saturated and subcooled water at high pressure. [PWR; BWR]

Abstract

Critical flow rate measurements have been made with saturated and subcooled water to determine the effect of fluid enthalpy, flow geometry and size, and flow length. These tests were conducted by blowing down vessels from an initial fluid pressure of 1000 psia (6895 kN/m/sup 2/) with the discharging fluid temperature between 450 and 550 F (232 and 288 C). The results clearly demonstrate the influence of metastable and/or nonequilibrium, thermodynamic states for flow lengths less than about 5 in. (127 mm). Data for different diameter nozzles, from 0.5 to 3.0-in. (12.7 to 76.2 mm), are presented which suggest that the critical mass flux decreases with increasing diameter.