Study on Test Scheme for Friction Properties and Service Life of Secondary Seal of Reactor Coolant Pump Hydrodynamic Shaft Seal

The friction properties and service life of the secondary seal are the key factors affecting the service life of the hydrodynamic shaft seal of the reactor coolant pump. In order to study the long-term service life of the secondary seal, a high-frequency reciprocating test device is established to simulate the reciprocating motion of the secondary seal under the high pressure medium condition, and the friction change data of the O-shaped rubber sealing ring and dual metal parts of the secondary seal under three working conditions of increasing frequency, increasing displacement amplitude and increasing medium pressure are obtained. The results show that the secondary seal of hydrodynamic shaft seal of the reactor coolant pump is in a fretting friction state under the normal operating condition frequency of 25 Hz, amplitude of about 30 μm and medium pressure of 5.3 MPa. The friction properties of the secondary seal will remain basically unchanged when the frequency is increased to a level no higher than 300 Hz under the normal operating conditions, but the friction properties will change significantly when the frequency is increased to a level higher than 500 Hz. The friction properties of the secondary seal will remain basically unchanged when the amplitude or the fluid pressure is increased under the normal operating conditions. It can be seen that the effect of increasing the frequency to a level below 300 Hz on the service life of secondary seal can be considered as linear increase, which can effectively reduce the service life verification time.