Measurement of wet steam mass flow through damper

The carrier of thermal energy in the secondary circuits of PWR nuclear power plants is wet steam whose mass flow it is necessary to measure directly for various reasons. The possibilities are therefore being studied of using damping elements applied so far in measuring single-phase flow, for wet steam metering. A relation is derived for the total mass flow of wet steam through sharp-edge dampers with off-take in corners. A preliminary assessment is given of the accuracy of such measurement. The accuracy seems to be equal to that in single-phase flow measurement, i.e., about 2%. It is recommended that for further development, the measurement of steam wetness should be more accurate and the possibility should be studied of replacing the damper with a measuring nozzle. (Z.M.). 3 figs., 12 refs