PPL Susquehanna decided to shut down the generating unit for inspection based on data from the extensive vibration monitoring equipment installed on the turbine, which indicated that a few blades had potentially developed small cracks.
With the unit shut down, workers performed an inspection and replaced one row of blades, although only a small number were found to have indications of cracking. Workers also performed additional maintenance activities that can be done only when the unit is not operating.
PPL Susquehanna installed newly designed blades on the Unit 1 turbine earlier this year that have significantly reduced blade vibration, which is believed to be a primary contributor to cracking. Based on Unit 1 blade performance, PPL Susquehanna is preparing to install similar blades during the next scheduled Unit 2 refueling and maintenance outage in the spring of 2015.
The Susquehanna plant, located in Luzerne County about seven miles north of Berwick, is owned jointly by PPL Susquehanna LLC and Allegheny Electric Cooperative Inc. and is operated by PPL Susquehanna.
