07.11.16

PLYMOUTH -- Pilgrim Nuclear Power Station is still struggling with the problem of not properly prioritizing or adequately following through with needed repairs on rundown parts.

On Wednesday, the Nuclear Regulatory Commission issued its report regarding a two-week inspection conducted at Pilgrim in mid-May.

Inspectors found corroded supports for piping that distributes cooling water to the reactor and other plant systems after it is pumped in from Cape Cod Bay.

Federal regulators classified the failure to replace the corroded supports as a "green" violation, which is considered of "very low safety significance," according to NRC spokesman
Neil Sheehan.

Yet the report went on to say the finding is considered "more than minor" because it is associated with equipment performance standards, and it adversely affects "the objective of ensuring the reliability, availability and capability of systems that respond to initiating events to prevent undesirable consequences (i.e. core damage)."

"We'll be following up on this," Sheehan said, who stressed the piping system was functional. "Even if they lost that system, they have other ways of cooling the plant. Nevertheless, the system does have importance."

The finding also relates to problem identification and resolution at the plant because Entergy did not take effective corrective actions to address the situation in a timely manner, "commensurate with their safety significance." Federal inspectors have leveled similar criticism regarding Pilgrim's performance in the past.

In this case, the report said, the corrosion issue in the piping system supports had been identified in October 2015.

Sheehan said Pilgrim had replaced or repaired a couple of the supports for the system, "but failed to identify some other supports in the overhead of the same system also showing signs of corrosion."

There are eight supports in the area for each of the two loops of water discharge piping, Sheehan said.

"In some ways, the degraded supports are typical problems being found at other aging nuclear power plants," said
David Lochbaum, director of the Nuclear Safety Project for the Union of Concerned Scientists in an email. "Workers tend to focus on moving parts (pumps, motors, dampers, valves) because they wear out faster. Workers tend to monitor passive parts (walls, piping supports, etc.) less aggressively because they tend to degrade more slowly."

In a report from the Nuclear Regulatory Commission last week, the agency noted that federal inspectors had found electrical relays at Pilgrim had long exceeded their shelf life. The relays are relied on to shut safety valves in the reactor building if an accident occurs.

The role of the valves is to prevent a radioactive release into the environment. The relays were 22 years old. The product vendor had recommended the relays be switched out every 10 years. Entergy declared the relays inoperable after the inspection, and the valves have been closed until the relays are replaced.

"Good management can effectively manage the opposing trends of increasing wear-out/replacements and the need to reduce operating costs," Lochbaum said. "When decisions about what to replace, when, and with what, are wrong, safety goes down and costs go up."

Pilgrim, which is 44 years old, is set to permanently shut down in mid-2019.

-- Follow
Christine Legere on Twitter: @chrislegereCCT.

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(c)2016 Cape Cod Times, Hyannis, Mass.