Abstract:

In view of the vacuum drop occurred during the operation of unit No.4 in a power plant, the vacuum system was checked for leaks within a helium mass spectrometer. Through leak detection, adjustment and analysis of the suspected areas, it is found that the breakage of the shaft seal pipe of the B steam feed pump turbine is the cause of the vacuum drop. After replacing the shaft seal pipe, the problem of vacuum reduction of the No.4 was effectively solved.The condenser vacuum returned to normal, and the vacuum tightness test passed.

Key words:

ultrasupercritical, vacuum drop, shaft seal, helium mass spectrometer, leak detection, vacuum tightness test