The safety performance rating for one reactor at PPL’s nuclear power plant near Berwick, PA, dropped a notch, federal regulators said.
As a result of its quarterly review of plant performance, the Nuclear Regulatory Commission (NRC) updated its assessment of Susquehanna Steam Electric Station’s Unit 2 reactor, the NRC said in a Nov. 5 letter to Timothy S. Rausch, PPL’s senior vice president and chief nuclear officer.
The NRC has a five-tier rating system for the 103 nuclear reactors in the United States. Reactor Unit 2 at PPL’s plant fell into the “Degraded Cornerstone Column,” which is the third tier of the “Action Matrix” the NRC uses in its Reactor Oversight Process.
The process uses seven “cornerstones” to describe the essential features of reactor safety, radiation protection and security. Performance in these cornerstones comes from assessments by the reactor owners and findings during NRC inspections.
As of Oct. 28, 93 of the nation’s nuclear reactors, including PPL Susquehanna’s Unit 1 Reactor, ranked in the first column of the Action Matrix, which is the “Licensee Response Column.” Reactors in this column had no significant problems and require no NRC action other than regular inspections.
Fourteen ranked in the second column — the “Regulatory Response Column” which required some additional scrutiny and inspections; six, including Susquehanna Unit 2, were in the degraded cornerstone column; one was in the “Multiple/Repetitive Degraded Cornerstone” column; and none was in the “Unacceptable Performance” column.
One reactor, which is not in any column, remains shut down because of significant performance and/or operational concerns.
Two years ago, PPL’s Reactor Unit 1 was in this same “degraded cornerstone” category because of an excessive number of unplanned shutdowns in a 7,000-hour operating period, but has since upgraded. Unit 2 downgraded to the third tier listing for the same reason.