Pressure suppression pool investigations. Report No. 1

Abstract

Investigations were made of suppression pool effectiveness and of pressure fluctuations and vibrations during steam blowdowns from a 10 ft./sup 3/ vessel into a 4-foot diameter water pool. Tests conducted under a variety of conditions indicated complete pool mixing. The only cases of imcomplete mixing were associated with low mass velocities and large distances from the vent exit to the nearest pool boundary. Downcomer submergence and initial pool temperature were shown to have very little effect on pool mixing. Air added to the steam flow had varying effects depending on the relative flow rates; under no conditions was air injection found to decrease pool mixing. An initial shock which can cause the suppression tank to jump is apparently due to the dynamic effects of the initial airsteam mixture. Vibration effects and pressure fluctuations were noted which are apparently related to a transition between sonic and subsonic flow at the downcomer exit. At low mass velocities, chugging at the downcomer exit. At low mass velocities, chugging at the downcomer exit occurs and results in level and pressure fluctuations within the vent.