Measurement of the void fraction in a channel simulating the HANARO fuel assembly using neutron radiography

A test section simulating the HANARO fuel channel was constructed and the void fraction was measured by using the high-speed neutron radiography technique. The test was performed at a beam facility of HANARO called Ex-core Neutron-irradiation Facility (ENF). D2O was used as the working liquid and air was used to simulate the void. The measurements were made at various combinations of the liquid flow and gas flow and the result were compared with the predictions of the existing correlations.