Groundwater

The Connecticut Yankee Atomic Power Company (CY) completed radiological groundwater monitoring in June 2007 to fulfill the requirements of the License Termination Plan, as required by the Nuclear Regulatory Commission (NRC). With this sampling program completed, CY was granted License Termination from the NRC on November 26, 2007.

To continue on the path to site closure, CY also closed its Resource Conservation and Recovery Act (RCRA) permit under the Environmental Protection Agency (EPA), moving closer to site closure. Now that all remediation, or clean up work, is completed, CY is working under a stewardship permit issued by the Connecticut Department of Environmental Protection (CTDEP). The stewardship permit was issued after all required corrective action measures,, or cleanups, were completed and all sampling procedures were implemented to monitor groundwater quality to ensure that the cleanup actions were effective.

CY continues to complete quarterly sampling to demonstrate compliance with the CTDEP Remediation Standard Regulations (RSRs). The sampling program includes 60 monitoring wells, 34 will be monitored for chemical constituents and 38 for radiological constituents.

The CTDEP groundwater monitoring program began following final site grading in June 2007, and will likely continue quarterly and/or semi-annually for the next four to five years. CY continues to work closely with the CTDEP to evaluate the data and to ensure that the remediation and demolition of CY was successful. The results from the first three quarterly rounds of sampling show non-detectable concentrations of sampled parameters, or levels below regulatory criteria, with the exception of 17 wells that have extractable total petroleum hydrocarbons (ETPH) concentration above RSRs, two of which also contained polynuclear aromatic hydrocarbons (PAHs) above the cleanup criteria. Samples from two additional wells also contain strontium-90 at detections slightly above Maximum contaminant levels (MCL).

The impacted wells are within the former industrial area of the site, downgradient of areas remediated for petroleum hydrocarbons and radionuclides. We expect the concentrations to decrease with time and at this point, do not anticipate any more soil excavation. CY will continue to work with CTDEP, and will continue to monitor groundwater until sample results are below the RSR criteria.

In addition to sampling wells at the CY site, groundwater samples that have been collected from the Haddam Meadows State Park, across the Connecticut River, do not contain plant related constituents. Additionally, at the end of demolition and remediation, the CTDEP sampled 126 private or residential wells near and around the plant; no CY related radioactivity was detected at any location.