The Nuclear Regulatory Commission has established a page on the agency’s website to consolidate information on concrete degradation at the Seabrook nuclear power plant. Seabrook is a single pressurized-water reactor located in Seabrook, N.H., and operated by NextEra Energy Seabrook, LLC.
Among the items on the web page are correspondence to and from the NRC regarding the issue, slides from a 2012 public meeting on the topic and graphics illustrating the condition. Information on the issue will be added to the page as it becomes available. The page’s address is: http://www.nrc.gov/info-finder/reactor/seabrook/concrete-degradation.html.
The concrete degradation at Seabrook is caused by alkali silica reaction. This is a chemical combining of reactive silica from the concrete aggregate with the alkali from the cement paste in the presence of moisture. (Aggregates are inert granular materials, such as sand, gravel or crushed stone that, along with water and cement paste, are an essential ingredient in concrete.) The result of the reaction is a gel, which can expand and may cause micro-cracks in the concrete.