The weld repair or rebuild of rotors represents an established method of returning a rotor to a fully operational condition in a time period much shorter than that normally required for the procurement of a new rotor. Also, the total cost involved will normally be considerably less than required for the purchase of a new rotor. When a situation occurs requiring a decision for the future operation of the unit because of degradation, the major concerns of unit operators are the reliability of these procedures, and the integrity and safety of such a weld repair. At this time, there have been no reports of weld failure in the many hundreds of rotors that have been weld rebuilt and returned to service.

In terms of cost, there are competing considerations. If a rotor is weld repaired, this will remove it from service for a period. Any operator considering weld repair should establish the cycle time associated with this repair, and compare it to the time for the procurement of new rotor. In doing this, it must be recognized that a deteriorated rotor can possibly be returned to service in the damaged condition until a replacement rotor is delivered. However, this option requires the unit be shut down a second time, and the damaged rotor removed for installation of the new. It is also quite possible that in returning the damaged rotor to service, it may be required to operate in a derated condition for a...