Infrastructure at the Seabrook Nuclear Power Plant is compromised due to an insidious form of concrete degradation known as the Alkali-Silica Reaction (ASR). Cracks have been found in all major structures at the plant, and they continue to expand today.
Concrete degradation is an extremely serious safety issue. Addressing this kind of damage and determining how to repair foundations at a live nuclear reactor site has never been attempted at a nuclear power plant before. Because of this issue, the NRC has suspended Seabrook’s relicensing process until further research has been carried out.
WHY IS CONCRETE DEGRADATION A PROBLEM?
Concrete is the primary material protecting us from the radiation of nuclear power plants. The containment dome, shielding walls, storage facilities, spent fuel pools, dry cask storage, foundations, floors, and other structures are all made primarily of concrete.
WHAT CAUSES ASR?
ASR happens when water is absorbed by concrete. The silicon in concrete becomes reactive in the presence of enough water, and a gel forms which then takes up even more water, expanding and exerting pressure within the concrete, weakening, and eventually resulting in failure of the concrete. ASR leads to critical structural problems and can even force the demolition of an affected structure.
Several factors exacerbate concrete degradation and ASR, including contact with saltwater, changes in temperature, high temperatures, and radioactivity. Every one of these factors is present at Seabrook.
THE HIDDEN PROBLEM OF ASR
ASR happens at the molecular level, so it’s often at an advanced stage by the time cracks become visible. Because of this, visual inspections are inadequate for determining the extent of damage and weakness within concrete structures. Core sampling, lab analysis, and ultrasound are needed in order to determine the full extent of degradation below the surface. Seabrook has yet to carry out these types of analyses.