SEABROOK — NextEra Energy Seabrook nuclear power plant officials say they feel they are making progress on implementing the program that oversees the plant’s alkali-silica reaction concrete degradation program, including plans to hire more staff in its policy of keeping safety its top priority.
In its 2015 performance review assessment letter to Seabrook Station owners, the Nuclear Regulatory Commission wrote that, while the plant operates safely overall, more is needed in its monitoring program that oversees the ASR issue present in many of the concrete walls throughout the nuclear power plant complex.
Specifically, the NRC wrote that, based on its findings from its mid-year inspections, the plant’s “corrective actions to implement multiple training, program, and oversight changes to correct the organizational mindset issues and strengthen individual responsibilities and accountability for implementation of the Seabrook Structures Monitoring Program have either not been implemented, or are not yet effective, and thus require additional management attention near term.”
The primary concern regarding “the organizational mindset” is the NRC inspectors’ belief that the company needs to kick up the “level of intensity and urgency” it brings to monitoring ASA-involved structures, according to NRC Region 1 spokesman Neil Sheehan, so corrective action can be taken immediately upon the identification of changes. This could include differential movement and deformation at ASA sites.
Asked to comment on the NRC’s finding, NextEra Energy Seabrook spokesman Alan Griffith responded that safety will always be Seabrook Station’s highest priority. The plant’s “plan to monitor and manage ASR for the long term is effective and comprehensive,” according to Griffith, developed by credentialed and qualified structural engineering experts.
“We have made significant progress and continue to take specific actions to implement our Structures Monitoring Program that include hiring additional staff and increasing our engineering resources,” Griffith said.
“In addition, we have established a leadership position directly responsible and accountable for providing management focus on ASR and who reports directly to our site vice president. We will continue our efforts to ensure that the actions we are taking to implement our Structures Monitoring are appropriate and timely.”
While NRC inspectors have seen improvement since they originally highlighted the problem in their Aug. 5 inspection report, the agency added the need for more diligence to its end of year 2015 assessment letter for Seabrook Station, Sheehan said. As a result, the agency will continue its close monitoring of NextEra on ASR issues.
A slow chemical reaction between the alkaline cement and reactive silica found in some concrete aggregates when moisture is present, ASR forms a gel that expands, causing micro-cracks that affect concrete properties. Commonly found in dams and bridges, ASR usually takes years — even decades — to make itself known. Over the long term, micro-cracks can stabilize or progress, which is the reason to monitor aggressively the areas of involvement.
Discovered in the concrete walls at Seabrook Station in May 2010 by the plant’s staff, the problem was reported to the NRC. The finding came just as NextEra was filing an application with the NRC to extend its operating license from 2030 to 2050.
Heightening plant inspections, the NRC assured the public that ASR has not affected the safety of Seabrook Station and the walls are structurally sound. The walls at the complex are two feet thick, and still meet federal standards for load-bearing capacity due to the lattice of steel rebar reinforcement within them, according to the regulatory agency.
Since ASR was discovered at Seabrook Station, the NRC said it will not approve Seabrook Station’s license extension request until it is convinced the power plant’s owner can satisfactorily demonstrate it has developed a long-term plan to address ASR at the plant as the plant ages.