Test results of jet discharge from a 4 inch pipe under BWR LOCA conditions

Abstract

This report describes the result of tests on jet discharge of saturated water through a 4 inch discharge pipe from a pressure vessel having 4 m 3 of inner volume, where the initial pressure was 69 kg/cm 2 g and the temperature was 283°C. Behind the exit, a 10 ton load cell was installed to measure thrust force due to sudden jet discharge. In front of the pipe exit a 1000 mm diameter target disk was installed. The distance from the pipe exit to the target was 500 mm. Thirteen pressure transducers and 13 thermocouples were mounted on the target disk to measure the pressure and temperature increase due to jet impingement on the target. The following conclusions were reached. 1. (1) Pipe reaction thrust is calculated using a homogeneous flow model at the early stage of blowdown where stagnation quality is low. It agrees closely with the experimental data. 2. (2) Maximum pressure on the target due to jet impingement is 1 kg/cm 2 g when the distance from pipe exit to target is 500 mm. 3. (3) Mass flow rate was calculated by RELAP4/MOD5. Agreement between computed and experimental results was reached based on the assumption that C D = 0.63 for a 4 inch discharge pipe.