NRC issues confirmatory action letter on commitments to address Seabrook Nuclear plant concrete degradation

The Nuclear Regulatory Commission staff has issued a Confirmatory Action Letter (CAL) to NextEra Energy Seabrook LLC, confirming regulatory commitments made by the company to address concrete degradation at the Seabrook nuclear power plant. NextEra owns the plant, which is located in Seabrook, N.H.

In the license renewal application for the Seabrook plant, NextEra identified concrete degradation at the facility in the form of alkali silica reaction, or ASR. A gel resulting from ASR can expand and cause micro-cracks in the concrete. At Seabrook, certain below-grade concrete structures have experienced groundwater infiltration, which in turn has induced ASR.

Based on its review to date, the NRC has determined the affected structures remain capable of performing their safety-related functions. However, in a letter sent to the company, the agency states that the information is needed to enable the NRC staff to ensure that adequate corrective actions are being taken to address the condition. The company is required to provide the NRC with a written response if it does not think it will be able to fulfill the regulatory commitments by the dates specified, and if the company proposes to change any of the commitments.

The NRC staff held a public meeting with Seabrook plant management on April 23rd to discuss the company’s actions to date on the issue. NextEra committed to provide additional information to the NRC regarding its upcoming testing, evaluations and other activities in response to the concrete degradation. May 3rd and 10th letters from NextEra to the NRC listed regulatory commitments to be completed and the dates for those activities. They include:

– Submitting a root cause assessment and an evaluation of the impact of ASR at Seabrook by May 25, 2012

– Revising the prompt operability determination for the “B” electrical tunnel exterior wall by May 25, 2012

– Submitting the corrective action plan for continued assessment of ASR in concrete structures at Seabrook, including the development of remedial actions to mitigate ASR effects, where warranted, by June 8, 2012

– Revising the prompt operability determination for several other ASR-affected structures by June 30, 2012

– Completing short- and long-term concrete aggregate expansion testing by June 30, 2012, and June 30, 2013, respectively, with results available to the NRC approximately 30 days after completion

– Submitting the technical details of the testing planned at the company’s contracted research and development facility, the University of Texas, by June 30, 2012

– Updating the plan for the monitoring of structures for ASR by July 15, 2012

– Performing initial six-month crack measurements and indexing at 20 locations in areas exhibiting the highest crack indices by July 15, 2012

– Completing an anchor test program by Dec. 31, 2012

Issuance of the CAL does not preclude the NRC from taking additional steps, including enforcement actions, for any violations of agency requirements that are identified.