Correlation of the analytical solution with experimental data on the electrolysis potential probe

In response to a loss of coolant (LOCA) in a water cooled nuclear reactor, the reactor vessel is reflooded with water from standby storage tanks to carry off heat that would otherwise damage fuel rods, vessel and other structures. During the latter phases of the reflooding, a mixture of steam and water flows between the structures and a flowing film of water adheres to the surfaces. To gain some knowledge about the behavior of these films and to aid heat transfer calculations in designing reactors, instruments have been developed for the measurement of film thickness, flow velocities, and mass flow rate in reactors and their simulators. The Electrolysis Potential (EP) Probe is one such instrument and is designed to measure average liquid velocity inside the films. It was discovered that if the EP Probe was excited with a constant voltage of sufficient magnitude to produce electrolysis, the current through the sensor decreased in a repeatable manner with increasing average film velocity.