ML052060357

Transmittal of Haddam Neck Plant, Third and Fourth Quarter 2004, Sampling Events Semi-Annual Groundwater Monitoring Report

ML052060357
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	04/07/2005
From:	Gerard van Noordennen Connecticut Yankee Atomic Power Co
To:	Hill P NRC/FSME, State of CT, Dept of Environmental Protection
References
CY-05 -110
Download: ML052060357 (3)

Text

CONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT 362 INJUN HOLLOW ROAD

• EAST HAMPTON, CT 06424-3099 April 7, 2005 CY-05 -110 Mr. Peter Hill, LEP Bureau of Waste Management Connecticut Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 Haddam Neck Plant Third and Fourth Quarter 2004. Sampling Events Semi-Annual Groundwater Monitoring Report

Dear Mr. Hill:

Connecticut Yankee Atomic Power Company (CYAPCO) hereby submits for your review the Semi-Annual Groundwater Report for quarterly groundwater sampling results from the Third and Fourth Quarter 2004 sampling events.

A key programmatic observation is that groundwater was observed discharging from the exposed bedrock surface as excavation of contaminated soil progressed in the service alley and PAB area. In November 2004, the HNP staff collected samples of the groundwater being expressed at visible bedrock seeps in the excavation area. The samples were submitted for on-site and off-site analysis, which resulted in detection of tritium, boron, and Sr-90.

Summary of Groundwater Sampling Results Sampling was conducted in September and December 2004. Ingeneral, observed concentrations of Sr-90, Boron and Co-60 increased during this period while tritium and Cs-1 37 levels decreased across the site. The observed increases in concentration occurred in wells located very near to areas of major demolition and soil removal where temporary mobilization of site contaminants due to demolition disturbance could be expected. The level of Sr-90 detected in the exposed bedrock seeps should be considered in the context of the decrease in Sr-90 concentration noted in monitoring wells.

g' sS5

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Mr. Peter Hill CY 110 Page 2 of 3 The maximum observed concentrations of selected SOCs and some general site trends based on the recent maximum concentrations are shown in the following table:

Maximum Observed Concentrations of Selected Substances of Concern for September and December 2004 Sampling Events Sept 2004 Location of Dec 2004 Location of General Substance Maximum Sept Maximum Dec Gend (pCi/L) Maximum (pCi/L) Maximum Trend Tritium 31,000 MW-103D 10,800 MW-103D Decrease Sr-90 7.3 MW-106S 8.6 MW-106S Increase Boron 581 MW-106S 802 MW-106S Increase Cs-1 37 2.3 MW-102S <MDC Decrease Co-60 < MDC 10.2 MW-1 03D Increase Maximum Observed Concentrations of Selected Substances of Concern for Seep Sampling Events Substance Maximum Location of (pCi/L) Maximum Tritium 3250 Seep #1 Sr-90 28.6 Seep #2 Boron 567 Seep #2 Cs-1 37 < 6.9 _

Co-60 <MDC I_____

Seep #2 is near the former location of monitoring well MW- 05S.

Recommendations Based on the review of the results of the third and fourth quarter 2004 quarterly sampling and observed long-term trends in some wells, several recommendations concerning subsequent groundwater monitoring sampling events are suggested in this section. The recommended analytical suite for the upcoming first quarter 2005 Groundwater Monitoring Program quarterly sampling event should be the same as the one implemented for the third quarter 2004.

Specific recommendations are as follows:

Collecting paired filtered and unfiltered samples is not necessary based on the data reduction effort and evaluation of analytical results performed in previous reports. Unfiltered groundwater samples should be collected from

Mr. Peter Hill CY 110 Page 3 of 3 all of the wells in the industrial area and analyzed for all constituents during the first quarter 2005 quarterly sampling event.

• The '500" series wells located in the parking lot should be sampled and analyzed for the full suite of radionuclides on one occasion to confirm that they are not impacted by plant-related radionuclides.

• Basic geochemistry analysis should be performed on the "500" series wells in the parking lot. This will require collection of field-filtered sample aliquots for analysis of cations and anions.

• Monitoring of the groundwater seeps in the excavation area should be continued.

• Sampling of the landfill wells should be suspended pending completion of soil remediation activities.

Otherwise, the wells sampled should remain the same as previous sampling rounds.

If you have any questions regarding this report, please call Chuck Miller at (860) 267-3977.

Sincerely, 694m/ WVl Gerard P. van Noordennen Date i ?0of Regulatory Affairs Manager

Attachment:

Semi-Annual Groundwater Monitoring Report CC: Mr. Michael Firsick, CTDEP, Bureau of Radiation Protection Mr. Gary Ginsberg, CTDPH Mr. Ron Bellamy, USNRC Region I Mr. Jon Pekenpaugh, USNRC Region 1 Ms. Marie Miller, USNRC Region 1 Mr. Ted Smith, USNRC Headquarters Mr. Juan Perez, USEPA Region 1 Mr. Marvin Rosenstein, USEPA Region 1 NRC Document Control Desk