According to NRC senior on-site inspector Paul Cataldo, based on 6,700 hours of inspections and related activities, the NRC determined Seabrook Station operated safely in 2016, “in a manner that preserved the public health and safety and protected the environment.”

Any negative findings and performance indicators related to the plant’s operation were of “very low significance,” Cataldo said. NextEra was cited for one more serious violation related to a 2015 security incident.

After the safety evaluation report, Jimi Yerokun, deputy director of the NRC’s Division of Reactor Safety, moved the discussion to the alkali-silica reaction (ASR) concrete degradation that has plagued Seabrook Station since discovery of ASR there in 2009.

ASR is a slow chemical reaction which can occur over time between cement and reactive silica present in some aggregates. The reaction forms a gel that expands and can cause micro-cracks that affect cement’s properties.

ASR is commonly found in highways, bridges and dams, but Seabrook Station is the only nuclear power plant in the United States reporting the problem, although it has been found in plants elsewhere in the world.

Since discovery at Seabrook Station, and after thousands of annual hours of inspection, NRC specialists determined the plant remains safe because the wall structure still meets federal standards for load bearing, according to Mel Gray, chief of the engineering branch for reactor safety. Walls at the power plant were built with “substantial margin,” Gray said, that includes a lattice of steel rebar reinforcing 2-foot thick walls.

Because of the presence of ASR, NextEra Energy Seabrook conducted a multi-year study of the problem at the Ferguson Structural Engineering Laboratory at the University of Texas. NextEra Energy also conduced tests on the concrete within the Seabrook plant, Gray said, drilling and pulling out core borings of ASR-affected cement from walls, and testing it. Gray said he was present when the testing took place.

Another topic discussed at the meeting by Seabrook watchdog group, C-10, is the relationship between NextEra’s recent submission of a request to amend its operating license to accommodate ASR, and the company’s 2010 application to extend its operating license 20 years, from 2030 to 2050.

C-10’s Diane Teed sought assurance from the NRC that the possible acceptance of NextEra’s license amendment request would not be used as a reason to approve the license extension application.

Yerokun told her that the two issues are handled independent of each other, although they are linked because both involve the ASR issue. He said if the NRC does accept the license amendment request it is not “automatic” that the license extension will be granted.

In a Tuesday interview with The Daily News, Yerokun said NextEra filed an amendment to its operating license because the presence of ASR in the plant’s concrete altered “the basis” of the plant’s original operating license.

In mid-June 2015, he said, NextEra presented its plan for revising its original licensing basis for its concrete structures affected by ASR, using, in part, the results of the University of Texas study. NextEra followed up on Aug. 1, 2016, by filing its official license amendment request. The NRC accepted the amendment in Oct. 2015, with the staff expecting to complete review of the lengthy and complex document by August 2018, if all goes as scheduled, Yerokun said.

As for the license extension application, the NRC’s environmental review required in the process was completed in 2015. The second portion of a license extension, the safety review, is on hold indefinitely because of the unresolved ASR issue, said Brian Wittick, branch chief of the Office of Nuclear Reactor Regulations for the NRC.

The safety evaluation for the license extension includes an in-depth review of NextEra’s aging management plans for all Seabrook Station’s systems and structures, including those affected by ASR. The outstanding issue is NextEra’s ability to prove to the NRC that its plan to manage ASR-affected concrete as the plant ages through the decades is sufficient to guarantee it will continue to run “in a manner that preserved the public health and safety…”

Angeljean Chiaramida can be reached at 978-961-3147, at, or follow her on Twitter @achiaramida1.