A quarterly performance report for the beleaguered Pilgrim Nuclear Power Station in Plymouth, MA, lists seven violations found by inspectors, related to procedural shortcomings and poor equipment maintenance.
The Nuclear Regulatory Commission (NRC) classified all findings as “more than minor” because of their potential to compromise essential safety systems in a radiological emergency, yet of “very low safety significance” because the shortcomings did not lead to an actual emergency at the plant.
One of the seven deficiencies involved written procedures that main control room operators follow when the air conditioning goes out, since temperatures above 120 degrees could cause the malfunction or failure of essential systems.
In mid-2016, inspectors noticed Pilgrim’s procedures were outdated, failing to factor in several changes in equipment through the years.
Entergy Corp., Pilgrim’s owner and operator, updated the procedures and resubmitted them in February.
Although the new procedures contained a long list of systems that could be shut off to address high temperatures in the control room, “No priority was made between shedding equipment that provided functions important to safety (radiation monitors, nuclear instruments, jet pump instrumentation) and control room lighting,” notes the third-quarter report.
As with several of the shortcomings in the report, federal regulators stated this was connected to poor human performance. Entergy fixed the procedures in late April.
In another violation, Entergy failed to replace a part in a safety relief valve for 24 years — since 1993 — that exceeded required replacement frequency. The safety relief valve failed when tested in late April. Entergy has since replaced the part in all four safety relief valves.
Improper maintenance has been an ongoing problem at Pilgrim.
The plant faced citations in this latest report for not appropriately establishing maintenance procedures for the high-pressure coolant injection turbine exhaust valves, which were not disassembled and maintained within the required 10-year time frame. As a result, the valves failed during testing. Entergy has since addressed the problem.
Another maintenance-related violation included failure to carry out a vendor-recommended modification to address damage to the main steam isolation valve system caused by an unstable main regulator. As a result, two valves were damaged. The company has since overhauled all eight of the isolation valves.
Entergy was also cited for failure to establish appropriate procedures for filling and venting a safety system used to inject coolant into the reactor during an emergency shutdown. As a result, the system was returned to service May 21 with a 2-inch gap that rendered it inoperable. It was not successfully returned to service until June 7, which exceeded the allowable outage time.
Despite the list of infractions, “the overall inspection record continues to indicate that Entergy is making slow progress in improving performance at Pilgrim,” said NRC spokesman Neil Sheehan.
Sheehan pointed out during refueling outages, such as the one Pilgrim underwent last spring, “it is not atypical for there to be an increased number of issues identified.”
Pilgrim’s status was downgraded by federal regulators in September 2015 to Column 4, which is one step above the mandatory shutdown of Column 5. Because of its ranking as one of the three worst performers in the country, Pilgrim was required to undergo 12,000 hours of federal inspection last year.
“The NRC’s third-quarter inspection report represents a continuing strong focus on finding and resolving issues at Pilgrim established both by the regulator and our dedicated staff,” said Entergy spokesman Patrick O’Brien. “The NRC categorized the seven findings in the report as very low safety significance, and Pilgrim’s staff is reviewing the report’s observations, with a goal of preventing recurrence. We remain focused on safe and reliable operations and are committed to meeting our regulatory requirements through the plant’s shutdown, planned no later than June 1, 2019.”