GE MS6001B, Maintenance Instructions Manual

Page: 274 / 370

Inspection and Maintenance — GEK 107048 Hot Gas Path Inspection — Inspection Procedures
HGP-I-6
Recommendations
1. First stage nozzles should not be removed for repair except at normal hot gas path inspection inter-
vals unless the above guidelines have been exceeded.
2. If the nozzle is removed earlier than hot gas path inspection interval for other reasons, all cracks,
damage, etc., should be carefully mapped using proper non-destructive test procedures and re-
ported to your General Electric Company Field Service Representative. Do not send to repair facil-
ity until mapping has been reviewed and specific Gas Turbine Division recommendations are re-
ceived from your General Electric Company Field Service Representative.
3. At all other times that the nozzle becomes partially or wholly accessible, the nozzle should be in-
spected as completely as possible using appropriate techniques and results reported to your Gener-
al Electric Company Field Service Representative.
4. All inspections should be reported using the PGS/GT-FF Field Inspection forms. It should be noted
that extreme care should be used to insure accuracy. False indications can occur when accessibility
is limited. Such false indications could result in major expense and lost time if not scrutinized and
properly interpreted. Record condition of nozzles on Inspection Forms Forms PGS/GT-FF-6095,
PGS/GT-FF-6096, PGS/GT-FF-6099, PGS/GT-FF-6102, PGS/GT-FF-6111 and PGS/
GT-FF-6112.
Operation 3 — How to Inspect First, Second and Third Stage Turbine Buckets
CAUTION
Each time the upper half turbine casing is removed the tur-
bine buckets should be carefully examined. Such exami-
nation can reduce the risk of major damage from the fail-
ure of a previously damaged bucket. At the same time,
judgment is necessary to avoid replacement of adequate
buckets. The recommendations contained herein are in-
tended to help in making this judgment, and the criteria for
continued service or repair of buckets are furnished as a
service to the customer.
There is a great variance in customer practices relating to
operation and maintenance, with accompanying variation
in influence upon satisfactory operation of gas turbine
components. General Electric Company has little knowl-
edge of or no control over these practices. Accordingly,
the responsibility for decisions as to continued usage or re-
placement of buckets must remain solely with each cus-
tomer.
1. The results of a bucket inspection should be documented along with the relative information on
unit operation and fuels. The inspection reporting forms, should be used to record and communi-
cate to General Electric Company the exact location and type of abnormality observed. These
bucket inspection records will be filed for each particular turbine and used as a basis for present
and future recommendations. Use Inspection Form PGS/GT-FF-6000, 6091, 6092 and 6093.