Seabrook Station Nuclear Power Plant
The discovery of alkali-silica reaction (ASR) in concrete structures at the Seabrook Station Nuclear Power Plant (Seabrook) was the first documented case of ASR at any U.S. nuclear facility. The Nuclear Regulatory Commission (NRC) required Seabrook to investigate the implications of this finding and Seabrook subsequently retained SGH to assess the existing, safety-critical structures for the presence of ASR and the evaluate the effects of distress on the structural performance.
SGH conducted field and laboratory investigations, including the following:
- Qualifying staff for unescorted access privileges to Seabrook
- Performing visual and digital imaging in constrained areas
- Crack mapping and measuring for cracking index calculations
- Collecting expansion measurements for long-term monitoring
- Completing petrographic examinations and Damage Rating Index Tests
- Testing for concrete modulus of elasticity and compression strength
- Conducting mortar bar expansion testing to evaluate future potential for continuing ASR of in situ concrete aggregate
For our evaluation, we analyzed the static and seismic performance of the structures with ASR-affected concrete. Our evaluation included the following:
- Creating a visual rating system correlated to tested properties
- Performing two-dimensional, dynamic analyses with design and distressed properties and three-dimensional analyses to redistribute internal forces
- Determining the affects of ASR on the concrete design properties
SGH used site data to analyze the structural performance with ASR-affected concrete. We then assisted the utility in developing and implementing a procedure for long-term monitoring. SGH conducts regular inspections to monitor the concrete structures. Our overall assessment system approach minimized destructive testing of safety-critical structures.
This project was completed in collaboration with NextEra Energy Resources, LLC. (owner).