Experimental study on the inertia characteristics of EM pump supplied by a flywheel

In order to confirm the concept that the inertia of EM pump is supplied by flywheel at loss of electric power in a liquid metal reactor, a small motor-generator which operates as a motor in the normal operation but as a generator at the emergency condition is designed and is applied to the EM pump installed in the sodium loop. The electric and fluidic characteristics after loss of external electric power are investigated. The decay rate of those characteristics is proportional to the initial electric current of EM pump and is inversely proportional to the inertial force of flywheel. Those characteristics nondimensionized by their initial values have shown the same tendency following the frequency of flywheel. In the present study the dimensionless time which can explain the decay rate of those characteristics is proposed based on the measured experimental data. It is shown that the decay rate of electric and fluidic characteristics can be described by this dimensionless time within ±10% error. The most important thing is shown to predict the frequency of flywheel by the dimensionless time and it is expected that the decay rate of other parameters can be predicted by the dimensionless time or frequency of flywheel