Effects of Medium Containing Free Gas on Hydraulic Performance of Certain Single Stage Centrifugal Pump in 3^rd Generation Reactor

Pumping medium containing gas has a negative impact on the centrifugal pump on mechanical properties (such as vibration, noise) and hydraulic performance, but also affect the accuracy of hydraulic test. in the GL2008-01 open letter, the United States Nuclear Regulatory (NRC) requires that some safety systems shall take into account the adverse effects of gas and the American Institute for Nuclear Research (NEI) and the Electric Power Research Institute (EPRI) pointed out the American Institute for Nuclear Research (NEI) and the Electric Power Research Institute (EPRI) pointed out that the gas in suction side shall not exceed the limit of 2% (volume ratio). In HPR1000, the 3rd generation reactor, it is the first time proposed that some systems are with long-term gas entrainment condition, and there is up to 3% (volume ratio) free gas in the horizontal centrifugal Spray Pump suction side water. In order to study the 3% gas entrainment condition effects on the hydraulic performance of Spray pump, a way is found to calculate the head drop by some equations and carried out a containing free gas hydraulic test. The results show that under the 3% gas condition, Spray pump head is 0.60% dropped by equation calculation and 0.66% dropped by test, comparing with no gas condition. The 3% gas effects on the Spray pump performance are very small. The reasons is that the structure of the Spray pump is well for vent during operation and the gas is not accumulate in the pump, so the performance of the pump has no effect.