Quake rattles anti-nuclear activists in N.H.

Government officials said an earthquake centered less than 10 miles from Seabrook Station Nuclear Power Plant didn’t seem to have caused any damage yesterday, but anti-nuclear activists are worried the tremors could have increased instability in alreadycracking containment walls.

The 9:28 a.m. quake, which shook the ground in northern Massachusetts and southern New Hampshire but only hit 2.7 on the Richter scale, didn’t trigger any emergency procedures at Seabrook Station, Nuclear Regulatory Commission spokesman Neil Sheehan said. The station is just down the road from the earthquake’s epicenter in East Kingston.

Sheehan said workers walked through the plant yesterday in search of any signs of damage, but stressed Seabrook Station is built to withstand much stronger earthquakes.

But activists said many of the plant’s walls — including in the spent fuel pool and the reactor dome — are already weakened. And though they’re several feet thick, they’ve been damaged by water mixing with compounds in the walls’ concrete and cement, creating a gel that expands and cracks the walls.

Paul Gunter, a director at activist group Beyond Nuclear and a former member of the Clamshell Alliance that led large protests against Seabrook coming online in the 1970s, said activists have long been concerned by the power plant’s proximity to an earthquake zone. He said yesterday’s tremor was a “wake-up call.”

“Even these small earthquakes are a wake-up call to look at the broader issues of vulnerability at the plant and the inherent danger of the operation,” Gunter said. “These are legitimate reasons to question the continued operation of Seabrook Station.”

Natalie Hildt Treat, executive director of C -10, a Newbury port based group that monitors emissions at the plant, agreed.

“You would think a measurable earthquake would put further stress on that,” she said. “Little cracks can lead to bigger cracks ... it’s definitely a safety concern.”

But Seabrook Town Manager William M. Manzi III said he wasn’t concerned that the quake caused any structural damage, saying, “We’re confident that the plant will be able to withstand any seismic event.”

Plant owner NextEra Energy didn’t respond to multiple requests for comment. The company is seeking to extend its license to operate from 2030 to 2050, and Sheehan said the NRC is currently reviewing NextEra’s plans to address deterioration before it considers an extension.

“The real issue here is longerterm,” Sheehan said. “In terms of the earthquake today, we don’t believe it poses a safety issue.”