The Bulletin Board

Federal regulators tell Seabrook to improve modeling of concrete degradation

By: - August 23, 2021 2:41 pm
An electricity meter on the side of a house.

The commission ruled the price was too high and would place “an enormous burden on New Hampshire ratepayers.” (Dave Cummings | New Hampshire Bulletin)

The U.S. Nuclear Regulatory Commission told Seabrook Station that the facility needs to do a better job modeling future degradation of concrete to ensure the structure is safe, according to a recent report.

Some structures at the nuclear energy generator, which is owned by NextEra Energy of Juno Beach, Fla., have what’s called alkali-silica reaction, or ASR, which can weaken concrete over time. The condition was first identified in 2009.

The report finds “NextEra staff did not adequately account for the future progression of alkali-silica reaction.” The main problem federal regulators highlighted is that Seabrook wasn’t accounting for the condition to expand in the future. The report also identified seven structures that may need to be modified to meet current safety codes because of structural issues with walls, slabs, or beams.

“The inspectors determined the performance deficiency was more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern,” the report says.

“Specifically, NextEra staff did not trend and project the periodic threshold monitoring data for the affected structural elements to ensure the structures would remain capable of performing their safety functions to the next scheduled inspection,” it continues.

The inspections are routine and completed once per quarter. While monitoring of the cracks was happening every six months, the recent report said it may need to happen as often as once every two to three months.

The federal commission gave out a “non-cited violation” to Seabrook for the deficiencies that they say are of low safety concern.

A nonprofit nuclear safety watchdog, C-10, said the report shows conditions may be worse than what they previously thought, with structures “exceeding structural design basis.” While the issues in the report were coded green, the least serious rating on the NRC’s safety scale, C-10 said the regulators are conservative when it comes to citations. In 2015, for example, the agency handed out only 13 white-ranked citations, one step more serious than green findings, of which there were 428 that year.   

In a written statement, a spokesperson for NextEra Energy said the finding was “of low significance” and that the company will comply with the recommendation in the report.

“Other than this minor finding, which we will improve upon, our program received a clean bill of health,” said Lindsay Robertson of NextEra. “The NRC has confirmed that Seabrook’s plan to monitor and address ASR is effective.”

The watchdog group said the NRC’s ongoing involvement should boost public confidence, “knowing that Seabrook’s ASR problem is getting tough scrutiny by NRC’s inspectors.”

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Amanda Gokee
Amanda Gokee

Amanda Gokee is the New Hampshire Bulletin’s energy and environment reporter. She previously reported on these issues at VTDigger. Amanda grew up in Vermont and is a graduate of Harvard University. She received her master’s degree in liberal studies, with a concentration in creative writing, from Dartmouth College. Her work has also appeared in the LA Review of Books and the Valley News.