Experimental study of heat transfer coefficients in ITER vacuum vessel cooling channels

The paper describes the results of thermal–hydraulic tests with single rectangular vacuum vessel (VV) channel models performed to measure heat transfer coefficients under typical VV fluid conditions. The experiments have been carried out on the thermal–hydraulic facility developed at the Central Boiler and Turbine Institute (CBTI) for wide-range tests of power plant equipments. This facility comprises a water loop 30 m in height designed for the full-scale study of nuclear reactor passive cooling. The VV test element is a rectangular channel 0.2 m in width, 3 m in total length, 2.48 m in heated length. The channel height (δch) is variable, i.e. δch=12.5, 25 or 50 mm. The heat transfer coefficients have been obtained as a function of flow rate, channel height, model inclination and heating power.