As for the unit 7, we have been conducting internal inspections of
the low-pressure turbine (A) by opening its cover.
As a result of the inspection, we found wears (maximum about 3mm) at
the edges of the rotor blades (shrouds of the 10th to 12th stage),
at the moisture separator blades (13th stage) and at the base of the
rotor blades (the 10th to 13th stage) at about 1:40pm on Nov.29th.
We suppose that they were caused by contact of the rotor blades and
the stator blades.
We also found a wear (maximum about 4.5mm), 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.
The contact points above of the unit 3 were found at the same points
of the unit 3 and 4, which we have already inspected. The size and
depth of wear is quite similar to each other.
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