As for the unit 7, we have been conducting internal inspections of
the low-pressure turbine (B) since Dec. 1st by opening its cover.
As a result of the inspection, we found wears (maximum about 2mm) at
the edges of the rotor blades (shrouds of the 10th and 12th stage),
at around 2:05pm on Dec.4th. We suppose that they were caused by
contact of the rotor blades and the stator blades. We also found a
wear (maximum about 1mm), which was also supposed to be made by
contact, at the base of the stator blade.
We will consider repairing the contact points of the rotor blades and
stator blades. In addition, we will also inspect rotor blades and
stator blades of the low-pressure turbine (C).
The contact points were found at the same points of the low-pressure
turbine (A), which we have already inspected. The size and depth of
wear is quite similar to each other.
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