Model Studies of Interloop Coolant Mixing in VVER-1000 in-Reactor Pressure Channel

Experimental studies of the mixing of loop flows of coolant in an in-reactor pressure channel of the VVER-1000 model reactor are presented. The water temperature was measured after the bottom of the model shaft upon feeding into one of the loops a flow heated by 70–80°C compared with the entry temperatures of other loops. The studies were performed with different flow rates in the loops. The design particulars of a VVER-1000 pressure channel model and the method of measuring the temperature in the flow after the shaft bottom are described. The temperature distribution after the bottom of the model shaft is represented in the form of isotherms. It is shown that their position relative to the connection pieces as well as the boundaries of the mixing region of the flows depends on the flow through the loops.