PPL said early June 25 that plant operators have again take Susquehanna Unit 2 offline to inspect its turbine blades.
Current plans call for PPL to install newly-designed blades, similar to ones installed at Susquehanna Unit 1 during a recent refueling outage, in the spring of 2015 during Susquehanna 2’s next planned refueling, according to GenerationHub.
Data from the extensive vibration monitoring equipment installed on the turbine indicates that a few turbine blades may have developed small cracks, PPL said in a news release.
"We have been monitoring turbine performance closely for the last several years, and continue to work with the manufacturer to address conditions that are associated with cracks developing," said Timothy Rausch, senior vice president and Chief Nuclear Officer. "We continue to take appropriate actions based on the monitoring data we are collecting to ensure long-term safety and reliability. That's why we decided to shut down Unit 2 now to inspect blades and replace any that are found to have developed cracks."
Turbine issues have continued to be a lingering concern for the Susquehanna units. Unit 2 was shut down March 1 for a planned inspection of the turbine blades. The inspection outage lasted until March 17 after workers replaced several dozen blades, although no cracked blades were found during the March review.
Susquehanna 2 was also offline briefly in March to repair a valve on a non-safety-related water supply pump.
In February of this year, PPL said it was working with Siemens resolve lingering issues connected with turbine blade cracking problems at Susquehanna 1 and 2. The company had taken the units out of service for a while in 2013 to address turbine blade problems.
PPL officials said turbine blade-related issues probably cost the company roughly $30m after tax in 2013.
In July of last year, operators reconnected Susquehanna Unit 1 to the grid after repairing one of four valves that control the amount of steam going into the turbine.
The two Susquehanna units are boiling water reactors (BWRs) that were commissioned in the 1980s. Together the Susquehanna nuclear units have more than 2,400 MW of generating capacity.