CHF correlation development using local liquid velocity under ERVC conditions

Abstract

In-vessel retention (IVR) through external reactor vessel cooling (ERVC) is a severe accident mitigation strategy that is applied in many light water reactors (LWR). Critical heat flux (CHF) is a key parameter which indicates the success of the IVR strategy. Previous research have limitations that the CHF models were developed in terms of averaged factors such as mass flux. In this thesis, laser induced fluorescence (LIF) and particle image velocimetry (PIV) technique was coupled to measure the velocity field of the fluid in a test section. The test section simulated the gap between the reactor vessel outer wall and the insulation. Air injection was used to simulate CHF conditions in the forced circulation water loop. Curved rectangular channel with 50 cm radius was devised to simulate flow path of the reactor vessel external wall. The channel was made of transparent acrylic. CHF prediction correlation was developed based on the velocity field data acquired from the experiment.