Pilgrim Nuclear Power Plant has “more work to do,” from the perspective of the Nuclear Regulatory Commission (NRC), after an assessment of the facility after its end-of-cycle performance review.
The review evaluated quarterly performance indicators (PIs) at the plant, along with inspection results and enforcement actions during all of 2014.
Determinations of plant performance end up based on a combination of inspection findings and performance indicators utilized by the NRC’s Reactor Oversight Process.
Those findings and indicators have color classifications ranging from green, for an issue of very low safety or security significance, to white, yellow then red, representing higher safety or security significance.
The plant’s PI for “Unplanned Scrams (shutdowns) with Complications” had moved from the lowest safety significance rating of green to white near the end of 2013.
Another PI for unplanned scrams, this one based on occurrences within 7,000 hours of operation, also changed to white, because of a third shutdown during that period.
Those two indicators pushed Plymouth, MA-based Pilgrim into what the NRC calls the Degraded Cornerstone Column of its action matrix during much of 2014, resulting in increased agency oversight of the plant.
Last fall, a team from the NRC began evaluating whether the issues at Pilgrim that triggered the increased oversight ended up satisfactorily addressed.
If the answer was yes, the NRC could remove the plant from that degraded status and the additional inspections would end, barring any new events.
The inspector’s work completed last month, and the NRC’s answer was to keep inspections ongoing.
While the NRC inspection team determined that, overall, “the company’s problem identification, root cause evaluation and corrective action plans were adequate,” the report also identified deficiencies in the implementation of corrective action plans, as well as in Pilgrim’s understanding of the causes of the issues.
“Our inspectors identified several examples where corrective actions were not completed as intended or were closed prematurely,” NRC Region I Administrator Dan Dorman said in a letter to Pilgrim owner Entergy.
“We expect Entergy to take the steps necessary to put in place corrective actions that will have a lasting impact and reduce the likelihood of unplanned scrams, or shutdowns,” Dorman said.
“Entergy was required to determine whether the scrams were linked by common causes, and what role the safety culture at Pilgrim played in the failures,” the recent assessment report notes. But it failed to assess this adequately, the NRC said.
Pilgrim also failed to implement proper procedures for corrective actions, and the NRC said that was “a significant programmatic deficiency that could lead to worse errors if uncorrected.”
The NRC also said the plant’s procedure for severe weather did not prescribe sufficient actions that would limit the likelihood of ice bridging – a major cause of power outages in the past – or place the plant in position to respond to a loss of offsite power (LOOP) without potentially upsetting plant stability.
The report also said the plant’s failure to conduct insulator testing prevented the station from assessing its insulator replacement strategy.
Overall, Entergy did not take effective corrective actions to address issues in a timely manner, commensurate with their safety significance, according to the report.
As a result, the plant has been issued two new white (low to moderate safety significance) inspection findings.
Those findings replace the two white performance indicators that initially led to the plant receiving additional scrutiny.
“The net effect will be that the plant will continue to receive heightened attention until the NRC can perform a follow-up team inspection and is satisfied the concerns have been resolved,” the NRC said.