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

NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

Office of Public Affairs, Region I 

2100 Renaissance Blvd., King of Prussia, Pa. 19406

E-mail: opa1@nrc.gov 

Site: www.nrc.gov

Blog: http://public-blog.nrc-gateway.gov

No. I-12-025

Contact: Diane Screnci, (610) 337-5330

 Neil Sheehan, (610) 337-5331

May 17, 2012

Email: opa1.resource@nrc.gov
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.

A copy of the CAL will be available in the NRC’s electronic documents system at: 

http://adams.nrc.gov/wba.

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