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 licence 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.
NextEra listed its regulatory commitments, along with completion dates in two May letters to the NRC.
- Submitting a root-cause assessment and an evaluation of the impact of ASR at Seabrook by 25 May.
- 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 8 June 2012.
- Revising the prompt operability determination for several other ASR-affected structures by 30 June 2012.
- Completing short- and long-term concrete aggregate expansion testing by 30 June 2012, and 30 June 2013, respectively, with results available to the NRC approximately 30 days after completion.
- Updating the plan for the monitoring of structures for ASR by 15 July 2012.
- Performing initial six-month crack measurements and indexing at 20 locations in areas exhibiting the highest crack indices by 15 July 2012.
- Completing an anchor test programme by 31 December 2012
NextEra 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.
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