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Groundwater extraction completed at Vermont Yankee

first_imgNorthstar Vermont Yankee,On November 18, Entergy Vermont Yankee officials told the Vermont Health Department that the 300,000 gallon objective for groundwater remediation had been met, and groundwater extraction has been terminated. Radioactive tritium had been discovered leaking into the ground at the Vernon plant last January. Approximately 309,000 gallons had been extracted, and about 9,000 gallons were cleaned and returned for re-use at the plant. The remaining extracted groundwater is being trucked to a licensed radioactive waste processing facility in Tennessee. Final truckloads are scheduled for the end of November. A separate water shipping process was completed on November 18. About 140,000 gallons of radioactive water generated during the April and May 2010 refueling outage was shipped to a different waste processing facility in Tennessee. This water (like water in the Condensate Storage Tank and many plant systems, including the reactor coolant system) is contaminated with radionuclides such as cobalt-60 and cesium-137, in addition to tritium.Both volumes of water had been stored in frac tanks on site. These tanks are about the size of the trailer portion of a tractor-trailer. Each holds about 20,000 gallons of water, and after they are decontaminated, these frac tanks will be shipped back to the vendor. Seven frac tanks were used to store condensate water on the west side of the plant within the Protected Area of the plant, which is heavily secured. The tritium frac tanks were outside the Protected Area on the south side, near the cooling towers.New Groundwater Monitoring Wells in Service Groundwater monitoring wells GZ-12D, 22D, 23S, 24S, 25S, 26S and 27S have been completed and were sampled for radioactivity on November 15. The Health Department will receive results of these samples once the results are validated. The Health Department will also get split samples from these wells to verify the analytical results. GZ-22D, where the D designates a deep well that goes to bedrock (about 30 to 70 feet below ground level), is near the Construction Office Building (COB) well. The COB well has not been used as a drinking water well since February 2010. The other new wells run along the length of underground piping from the Advanced Off-Gas Building to the plant stack, and are intended to detect leaks from this piping system into the groundwater. The S designation on most of these wells is because they are shallow wells that do not go all the way to bedrock. They are drilled to depths of 25 to 35 feet.Groundwater Monitoring Well ResultsAs has been the trend over the past few months, tritium concentrations in groundwater near plant structures, systems and components are generally decreasing, while tritium concentrations in the wells near the Connecticut River continue their trend of slowly increasing in concentration. Since early August, the GZ-14 well on the river’s edge is where the highest tritium concentrations have been measured.To date, gamma spectroscopy and special analyses for hard-to-detect radionuclides have not identified any other nuclear power plant-related radioactive materials in groundwater, drinking water or river water. NRC Concludes Groundwater InspectionThe US Nuclear Regulatory Commission (NRC) held an exit meeting at Vermont Yankee on November 18 concerning the results of its groundwater protection program inspection that was initiated August 14. The purpose of the exit meeting was to brief plant staff and conclude the inspection. A written inspection report must be published by the NRC within 30 days of the exit meeting. Until that report is completed, all inspection findings are considered preliminary.This inspection focused on Entergy Vermont Yankee’s efforts to meet the criteria of the Nuclear Energy Institute (NEI) voluntary groundwater protection initiative. A health physicist from the Vermont Department of Health participated in many aspects of the inspection. The NRC investigation covered Vermont Yankee’s:Site Conceptual Model ‘ to depict likely groundwater flows, the interface between the bedrock and the overburden above it, the connection between groundwater in the overburden and drinking water sources in the bedrock below, characteristics of the soils on site, and flow of groundwater to the Connecticut River.Groundwater Monitoring ‘ processesand methods to monitor plant structures, systems and components for leaks of plant materials that could enter the environment.Tritium Investigation ‘ to identify and remediate the source(s) of tritium in the groundwaterand radioactive metals in the soils near the leakage pointson site.Source: Vermont Department of Health. November 23, 2010last_img read more