PPL Corp. reduced power at both units at the 2,450-megawatt (MW) Susquehanna nuclear plant in Pennsylvania and was preparing to shut Unit 1 later this month for additional turbine inspections.
The reason the company is doing this is to confirm data provided by new technology that could lead to the finalization of a plan to resolve the issue of turbine blade cracking first identified in 2011.
Pending the outcome of the 1,260-MW Unit 1 inspections, PPL said it will decide whether to do a similar inspection of the 1,190-MW Unit 2 turbine.
In 2011, PPL shut Unit 1 from March 31-June 7 for planned refueling and to replace some damaged turbine blades. The company also shut Unit 2 from May 30-June 15, but found no turbine blade cracks.
During the upcoming Unit 1 outage, PPL said workers will inspect turbine blades for any indications of cracking similar to what they previously found.
“Maintaining our margins of safety is the top priority,” said Timothy Rausch, PPL Susquehanna senior vice president and chief nuclear officer.
“As a result of these efforts and our ongoing, detailed engineering analysis, we are in the final stages of verifying the causes of the cracking and implementing both short-term and long-term measures to resolve the cracking issues,” Rausch said.
PPL said it reduced the power level of both units and would keep them reduced at least until the inspection of the Unit 1 turbine is complete to reduce the potential for cracking to occur or worsen and maintain operating safety margin.
PPL reduced the power output of both units from full power to 85 percent by Oct. 3.
The company said it would implement turbine modifications designed to resolve the turbine blade cracking issue during future scheduled refueling and maintenance outages starting in the spring of 2013.