CY-05-047, CY-HP-0193, Rev 0, Connecticut Yankee Decommissioning Health Physics Department Technical Support Document, Assessment of Existing Groundwater Dose for Phase II Release Areas of the Final Status Survey

CY-HP-0193, Rev 0, Connecticut Yankee Decommissioning Health Physics Department Technical Support Document, Assessment of Existing Groundwater Dose for Phase II Release Areas of the Final Status Survey

ML051660540
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	02/22/2005
From:	Mcgrath R, Mill C Connecticut Yankee Atomic Power Co
To:	Document Control Desk, NRC/FSME
References
CY-05-0470 CY-HP-0193, Rev 0
Download: ML051660540 (105)

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{{#Wiki_filter:CY-HP-0193 CY HEALTH PHYSICS TECHNICAL SUPPORT DOCUMENT Connecticut Yankee Decommissioning Health Physics Department Technical Support Document HIP Number: CY-HIP-0193 Revision #: 0

Subject:

Assessment of Existing Groundwater Dose for Phase H Release Areas of the Final Status Survey Report Date: 2/15/05 Performed By: Richard N. McGrath Date: 2/15/05 Reviewed By: (Lk)- .J /h;, Date: Z2 jb 's4 Approved By: , _ A7& Lh* Date: 2. 1 2 Z-' eas-; Page 1 of 10

CY-BP-0193 Assessment of Existing GroundwvaterDosefor the PhaseII Release Areas of the Fimnal Status Survey Report 1.0 PURPOSE The Haddam Neck Plant (HNP), License Termination Plan (hereafter called LTP) requires that the potential dose to a hypothetical future resident of the Haddam Neck Plant (HNP) site be determined for each survey area at the time that the request is made to the Nuclear Regulatory Comnmission (NRC) to remove the survey unit from the HNP license. This document provides the determination of existing groundwater dose for the survey areas/units within the Final Status Survey (FSS) Phase II Release Area. The FSS Phase 11 Release Area includes Survey Areas 9523, 9524, 9525, 9526, 9528 (Units 0000, 0003, 0004), 9535, 9536, 9537, 9538, and 9806 (See Table 1 for a complete list of survey areas and units). It should be noted that this assessment considers only radiological contamination. Groundwater sample results for other contaminants are addressed in other documents.

2.0 BACKGROUND

2.1 Groundwater Monitoring Program The Groundwater Monitoring Program is described in Reference 5-1, "Groundwater Monitoring Program". The program is intended to integrate all aspects of groundwater characterization, monitoring and remediation required to support HNP closure decisions. The program scope includes groundwater related requirements defined by multiple regulatory standards and includes specification, maintenance, and operation of specific infrastructure and monitoring systems. The program is responsible for the construction, maintenance, operation and ultimate decommissioning of the facilities and instrumentation that comprise the physical systems required to support groundwater monitoring data collection and decision management. The program is controlled through Reference 5-2, the "Groundwater Monitoring Program Quality Assurance Plan" (GWMP QAP) and applicable implementing procedures. Reporting results of a groundwater monitoring sampling event procedurally includes:

• Data Quality Assessments (DQAs) of field parameters Off-site laboratory quality assurance results
• Data reduction
• Assessment of conclusions and recommendations
• Internal HNP review prior to publication for distribution.

Page 2 of 10

CY-HP-0193 The installation of new groundwater wells procedurally requires identification of specific Data Quality Objectives (DQOs) to optimize the location, configuration, and intended use of the well(s). 3.0 Discussion and Dose Calculation 3.1 Discussion and Evaluations Certain survey units in the Haddarn Neck site need to be evaluated for potential dose to a hypothetical future resident of the site due to existing groundwater. Table 1 below shows the survey units included in the FSS Phase II release area for the HNP site that have been identified for an existing groundwater assessment (See Attaclument 1). Table I FSS Phase II Release Area - Survey Units with Potential for Existing Groundwater Impact Survey Survey Class General Description of the General Site Potentially Area Unit Survey Unit (Per LTP) Location Affected by Groundwater 9523 0000 3 Southeast Wetland Area Lower Discharge No Canal 9524 0000 3 South Site Grounds Southeast Landfill No 9525 0000 3 Southeast Site Road Southeast Mountain No l_ Side 9526 0000 3 NortheastMountain Side Northeast Mountain No Side 9526 00D1 2 NortheastMountain Side Northeast Mountain No __ _ .Side 9526 0002 2 NortheastMolountain Side Northeast Mountain No Side - 9528 0000 3 Southeast Mountain Side Middle Discharge Yes Canal 9528 0003 2 Southeast Mountain Side Middle Discharge Yes Canal 9528 0004 2 Southeast Mountain Side Southeast No Mountain Side 9535 0001 1 SoutheastLandfillAt-ea Southeast Landfill No 9535 0002 2 Southeast Landf1llArea Southeast Landfill No 9536 0000 2 ConstructionPiles Near Southeast Landfill No Rifle Range 9537 0000 2 PermittedLandfillArea Southeast Landfill No 9538 0000 2 MaterialStorage Area Southeast Landfill No 9806 0000 A Southeast Landfill Southeast Landfill No Page 3 of 10

CY-BP-0193 It can be seen from Table 1 that there are two site survey units which are part of the FSS Phase II release area that require an evaluation of existing groundwater dose. These will be discussed in the following, along with a discussion of groundwater monitoring results in the area of the Southeast Landfill. 3.1.1 Middle Discharge Canal Area provides an evaluation of the information collected to date on the nature and extent of possible groundwater contamination on the peninsula area of the site. The conclusion of Attachment 3 is that the source of the low level detections on the lower peninsula (Middle Discharge Canal Area is a part of the lower peninsula) is known, and based on this information, the concentrations in groundwater monitoring wells are not expected to be higher than already measured in these wells. Based on this conclusion, the groundwater monitoring data collected to date for the Middle Discharge Canal Area can be used to perform a final "existing" groundwater dose calculation for the affected survey units. It can be seen from Figure 1 of Attachment 1, survey units in the vicinity of the middle discharge canal are within the capture zone of groundwater monitoring wells exhibiting detectable levels of radioactivity. "Detected Groundwater Contamination" is defined in the CY LTP Section 5.4.7.1 as the presence of:

• Plant-related radionuclides, which are also present in background, at a concentration greater than two standard deviations over background, or
• Plant-related radionuclides, not present in background, at a concentration greater than the Minimum Detectable Concentration (MDC) and greater than two times the standard deviation in the net concentration.

The use of the MDC as the criteria for "Detectable Groundwater Contamination" is acceptable due to the very low level sensitivity that the analytical laboratory is required to achieve. While other measures, suchi as the two sigma error of the analysis or the 95% critical level are often used as a metric of detection (i.e., is the sample different from background?), these are often subject to higher than expected false positive error rates. The MDC states the actual measurement capabilities, which can be measured reliably, given the actual sample counting conditions. Stated another way, the MDC is the radionuclide concentration level required to give a specified high probability that the sample level is greater than the two sigma error or critical level. Table 2 lists the contractually Required MDCs that the off-site laboratory is required to achieve for CY groundwater samples. As can be seen in Table 2, the required MDC for each radionuclide is set at a value that is less than five percent (5%O/) of the corresponding 25 inrern/yr Groundwater DCGL. It can be seen that in most cases the required MDC is significantly lower. Page 4 of 10

CY-HP-0193 A review of analytical results indicates reveals laboratories consistently achieve analytical MDCs that are fifty percent (50%) or less of the required MDC. The conclusion is when a sample result is less than the analytical MDC it can be confidently stated that the potential groundwater dose for that radionuclide is less than fifty percent (5%) of the 25 mrem/yr groundwater DCGLs, and is not required to be included with the dose assessment consistent with LTP section 5.4.7.2, Gross Activity DCGL. Table 2 Groundwater Monitoring Well Sample Analysis Sensitivities Required Analysis Required Analysis 25 mrem/yr Minimum MDC as a Radionuclide Groundwater Detectable Percentage of the DCGL (pCiIL) Concentration 25 mrem/yr (MDC) (pCifL) DCGL (%/O) H-3 652,000 400 0.06 C-14 9,010 200 2.2 Mn-54 24,200 50 0.21 Fe-55 65,400 25 0.04 Co-60 1,140 25 2.2 Ag-108m 4,240 50 1.2 Ni-63 31,500 15 0.05 Sr-90 251 2 0.80 Nb-94 6,750 50 0.74 Tc-99 26,400 15 0.06 Cs-134 342 14 4.1 Cs-137 431 15 3.5 Eu-152 7,330 50 0.68 Eu-154 5,050 50 0.99 Eu-155 32,500 50 0.15 Pu-238 15.1 0.5 3.3 Pu-239 13.6 0.5 3.7 Pu-241 460 15 3.3 Am-241 13.2 0.5 3.8 Cm-243 19.4 0.5 2.6 Of the FSS Phase II survey areas adjacent to the middle portion of the Discharge Canal, only Survey Units 9528-0000 and 9528-0003 are within the capture zone of a monitoring well exhibiting detectable groundwater contamination. As seen in , Survey Unit 9528-0002 is within the 100 meter capture zone of the Upper Peninsula area where limited decommissioning activities are ongoing (9520-0003 is the nearest survey unit). Therefore, potential groundwater impacts to of Survey Unit 9528-0002 will be reevaluated in the future. Page 5 of 10

CY-HP-01 93 As shown in Attachment 1, groundwater monitoring wells within the capture zone radius of Survey Unit 9528-0003 that have shown detectable plant related contamination are MW-2 and Supply Well B. Additional, Attachment I shows the only groundwater monitoring well within the capture zone distance of 100 meters of Survey Unit 9528-0000 that has shown detectable plant related contamination is MW-2. Sampling results for MW-2 and Supply Well B were reviewed for potential existing groundwater dose impact. Results of that review are shown in the following. Table 3 Middle Discharge Canal Area Groundwater Sample Results Monitoring Number of Most Recent Detected Comments Well Number Sample Rounds Sample Round Groundwater Contamination MW-2 5 Dec 04 Dec 02: Pu-241 Pu-241 Sept 04: H-3 Detection is a False Positive l_ (See Table 4) Supply Well 2 Dec 04 Jan 02: Sr-90 None B _ _ _ __I_ _ I _ _ _ I__ _ _ _ _ I__ _ _ _ I__ As~indicated in Table 3, few sample results qualify as detectable contamination per the LTP. Table 4 provides additional details on the sample results that qualified as detectable contamination. Table 4 Detailed Sample Results & False Positive Determination Middle Discharge Canal Monitoring Wells MW Sample Radio- Sample 2 Sigma Minimum Positive Limiting Bias Well Date nuclide Result Uncer- Detectable Results of Mean Adjusted (pCiUL) tainty Concentra Total for the MDC (pCi/L) -tion Results for Sample (pCi/L) (pCi/L) the Sample Round I Round (pCi/L) MW-2 Dec02 Pu-241 11.2 3.62 6.34 21 of 21 10.45 16.79 MW-2 Sept 04 H-3 439 193 300 N/A N/A N/A SW-B Feb 02 Sr-90 1.02 0.35 0.45 N/A N/A N/A The Tritium (H-3) sample result is slightly above the MDC, meets the LTP criteria for detectable groundwater contamination and will be included in the dose assessment. Page 6 of 10

CY-HP-0193 When all the Pu-241 sample results for the December 2002 sampling round are considered together (as is done in Table 4), there is a significant positive bias in the laboratory analysis for this sampling round. A positive bias is indicated when the results for a sampling round show some or all of the following trends:

• For a radionuclide not expected to be present, a high percentage of the results are positive (i.e. greater than zero). If no analytical bias is present, and a normal distribution is assumed, it is expected there will be a relatively even split of negative (i.e. results less than zero) and positive results for a given radionuclide. In the case of Pu-241 (Table 4), all 21 sample results for the December 2002 sampling round are positive.
• For a radionuclide expected to be present in some of the samples for a sampling round (i.e. Sr-90), a parametric statistical evaluation of the sample results can be determine the magnitude of the bias. The parametric statistical test determines the underlying background distribution or limiting mean for a certain radionuclide for a sample round. The limiting means have been determined for much of the groundwater characterization data and have been reported in the periodic CY Groundwater Monitoring Reports.
• For a radionuclide not expected to be present, the average concentration of all groundwater samples for that radionuclide in a sample round is positive and a significant percentage of the analytical MDC. A limiting mean can also be determined for these data sets using parametric statistics.

With two of the above three trends shown (the only two that are applicable), a positive bias is indicated for December 2002 Pu-241 sample result. In cases such as this, the analysis MDC must be adjusted to include the analytical bias and the results re-evaluated against the detection criteria. This adjustment has been done in Table 4 by adding the Pu-241 limiting mean for the December 2002 sample round to the analysis MDC. It was also checked that the Bias Adjusted MDC was less than 5% of the DCGL for Pu-241. Based on this reevaluation, the December 2002, Pu-241 result is determined to be a false positive. The Sr-90 result for February of 2002 (Supply Well B) was not taken as part of a sampling round and therefore there are not a sufficient number of samples taken at the same time to evaluate analytical bias. The Sr-90 result will therefore be presented as detectable groundwater contamination even though a follow-up sample collected in December of 2004 did not show "detectable groundwater contaminatioon". For Survey Unit 9528-0003, the highest existing groundwater dose, within the zone of influence of these survey units, is associated with the January 2002 Sr-90 sample result for Supply Well B (1.02 pCiIL). H-3 was not detected in that sample of Supply Well B and therefore no H-3 dose need be included. Using the CY Page 7 of 10

CY-HP-0193 LTP 25 mrem/yr Groundwater Derived Concentration Guideline Level (DCGL) for Sr-90 of 251 pCi/L for Sr-90, the calculated dose would be 0.102 mrem/yr. As this is approximately 0.4 percent of the 25 mrem DCGL, consistent with the CY LTP, this dose is not required to be included in showing compliance with site unrestricted release criteria. For Survey Unit 9528-0000, the only sample result qualifying as detectable groundwater contamination is the September 2004 H-3 result for MW-2(439 pCiAL). Using the CY LTP 25 mrem/yr Groundwater Derived Concentration Guideline Level (DCGL) for H-3 of 652,000 pCi/L, the calculated dose would be 6.73 E4 mrem/yr. As this is approximately 0.003 percent of the 25 mrcm DCGL, consistent with the CY LTP, this dose is not required to be included in showing compliance with site unrestricted release criteria. In conclusion, the dose from existing groundwater contamination present in the monitoring wells within the capture zone of Survey Units 9528-0000 and 9528-0003 is insignificant and need not be included in showing compliance with site unrestricted release criteria per the protocol defined in the CY LTP Section 5.4.7.2, Gross Activity DCGLs. 3.1.2 Southeast Landfill Area There are a number of monitoring wells located near the Southeast Landfill Area Table 7 below summarizes the groundwater monitoring results for these wells. Table 5 Southeast Landfill Area Groundwater Sample Results Monitoring Number of Most Recent Detectable Comments Well Number Sample Sample Groundwater Rounds Round Contamination MW-200 5 Dec 04 No None MW-201 4 Jun 02 No WaterLevel too Low to Sample After Jun 02 MW-202 6 Dec 04 No None MW-203 8 Dec 04 Dec 01: Ni-63, False Positives (See Mar 02: Tc-99 Table 6) MW-204 6 Dec 04 No None MW-205 7 Dec 04 No None MW-206 6 Dec 04 No None MW-207 8 Dec 04 Dec 01 : Pu-238, False Positives (See I Sept 03 : Sr-90 Table 6) MW-208 4 Dec 04 Dec 03 : Sr-90 False Positives (See I Filter/Unfiltered Table 6) Page 8 of 10

CY-HP-0 193 As indicated in Table 5, there are a few samples qualify as detectable contamination per the LTP. Table 6 provides more details on the sample results that qualified as detectable groundwater contamination. Table 6 Detailed Sample Results & False Positive Determination Landfill Monitoring Wells MW Sample Radio- Sample 2 Sigma Minimum Positive Limiting Bias Well Date nuclide Result Uncer- Detectable Results of Mean Adjusted It(pCi/L) tainty Concentra Total for the MDC (pCiTL) -tion Results for Sample (pCiIL) (pCi/L) the Sample Round Round (PCi/L) _ 203 Dec 01 Ni-63 7.43 3.8 6.1 14 of 14 4.31 10.41 203 Dec 01 Pu-238 0.136 0.1 0.11 24 of 26 0.284 0.394 203 Dec 01 Am-241 0.199 0.15 0.18 12 of 14 0.102 0.282 203 Mar02 Tc-99 13.9 8.07 11.3 23 of 23 5.78 17.1 207 Dec 01 Pu-238 0.379 0.19 0.071 24 of 26 0.284 0.355 207 Dec 01 Pu-238 0.16 (< 0.14 0.22 24 oE26 0.284 0.504 Recount MDC)____Q__ 207 SeptO3 Sr-90 0.437 0.239 0.415 34 of 34 0.30 0.715 208 Dec 03 Sr-90 0.891 0.32 0.478 66 of 67 0.45 0.928 (Un-filtered) 208 Dec 03 Sr-90 0.52 0.266 0.448 66 of 67 0.45 0.898 _(filtered) When all the sample results for a particular radionuclide during the corresponding sampling round are considered together (See Table 6), it can be seen that there is a significant positive bias in the laboratory analysis for all of the radionuclides that exhibited detectable groundwater contamination. Using the same evaluation techniques as discussed in Section 3.1.1 for Pu-241, the following was determined:

• In all the cases in Table 6, even though none of the radionuclides were expected to be present, essentially all of the results are positive.
• Although detection of Sr-90 is expected in some monitoring wells on the CY site, as can be seen in Table 6, the limiting mean of the Sr-90 data for the applicable sample rounds is positive and nearly the same magnitude as the analysis MDC.
• For all radionuclides that exhibited detectable groundwater contamination in the landfill area monitoring wells that were not expected to be present, the average concentration of all groundwater samples for the radionuclide Page 9 of 10

CY-HP-01 93 for a sample round was positive and a significant percentage of the analysis MDC. A limiting mean was also determined for these data sets. For all of the sample results listed in Table 6, two of the above three trends are shown (all that are appropriate for the radionuclide being reviewed), therefore, a positive bias is indicated. In cases such as this, the analytical MDC can be adjusted for the positive bias and the results re-evaluated against the detection criteria. This adjustment has been done in Table 6 by adding the limiting mean for the appropriate sample rounds to the analysis MDC. A review of the last column of Table 6 (Bias Adjusted MDC) shows that none of the sample results are considered detectable groundwater contamination per the definition in the CY LTP. For the December 2001 sample round the initial result for Pu-238 was slightly above the adjusted MDC. A sample recount yielded a value well below both the unadjusted and adjusted MDC. Therefore, there was no detectable groundwater contamination in that sample. In summary, there is no existing groundwater contamination in the monitoring wells within the capture zone of Southeast Landfill Area survey units; i.e., no wells need be included in showing compliance with site unrestricted release criteria per the protocol defined in the CY LTP section 5.4.7.2, Gross Activity DCGLs. 4.0, Conclusions The preceding analyses show that for all the survey units in the FSS Phase II release area of the Haddam Neck Plant site, there is no "existing groundwater contamination" dose that needs to be included in showing compliance with site unrestricted release criteria per the protocol defined in the CY LTP. 5.0 References; 5.1 Ground Water Monitoring Program; RPM 5.3-0 Rev. CY-00 I Major 5.2 Groundwater Monitoring Program Quality Assurance Plan, GWMP QAP, current revision 5.3 Connecticut Yankee Haddam Neck Plant License Termination Plan, Rev. 2 Page 10 of 10

CY-BP-0193 Attachment 1 Haddam Neck Plant License Termination Plan Supplemental Information - Survey Areas Potentially Affected by Groundwater Contamination and Capture Zone Analysis

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

• EAST HAMPTON, CT 06424-3099 January 31, 2005 Docket No. 50-213 CY-05-022 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Haddam Neck Plant License Termination Plan Supplemental Information - Survey Areas Potentially Affected by Groundwater Contamination and Capture Zone Analysis The Haddam Neck Plant (HNP) License Termination Plan (LTP) Section 5.4.7 requires a notification to the NRC for any changes to the survey areas to which the "existing groundwater' dose term of the compliance equation (Equation 5-1 of the LTP) is to be applied. The HNP LTP also requires preparing and making available for NRC inspection, a capture zone analysis. As a result of additional groundwater characterization activities and the completion of the capture zone analysis, changes have resulted in the list of survey areas to which the uexisting groundwater" term needs to be considered. The purpose of this letter is to submit these changes.

Connecticut Yankee Atomic Power Company (CYAPCO) hereby provides the attached report (Attachment 1) which presents the results of the capture zone analysis for the Haddam Neck Plant site. Using the largest capture zone determined by the analysis, the zone of Influence was confirmed to be no more than the 100 meters currently used in the HNP LTP. A difference was determined concerning the directions in which the capture zone is to be applied from a groundwater monitoring well. The attached report calls for the capture zone to be conservatively applied in all directions from the monitoring well and not just on the flanks of the plume as currently specified in the HNP LTP. The effect of this change is discussed below. Additional groundwater characterization has been conducted since the determination of which survey areas needed to consider the "existing

US NRC - Document Control Desk CY-05-022, Page 2 groundwater" dose term included in the HNP LTP. Sample results have shown some low levels of detectable ground water contamination, as defined in the HNP LTP Section 5.4.7.1 (Hereafter called detections), in additional wells along the flanks of the industrial area plume and in certain wells on the peninsula between the discharge canal and the Connecticut River. Although the calculated dose to a hypothetical future resident due to these additional detections is very low (i.e.,

< 0.6 mremlyr), the affected survey areas will be included in Table 5-3 of the HNP LTP to ensure that the potential for dose is considered.

Discussion The groundwater monitoring characterization results have shown low level (in some cases intermittent) detections of radiological contaminants in the following additional wells compared to those currently described in the HNP LTP: Monitorinq Well Location MW-1 Central Peninsula MW-2 Central Peninsula MW-104S Northern Industrial Area MW-108S. Southern Industrial Area MW- 13S Upper Peninsula MW-117S Central Peninsula MW-122S (Installed after LTP Rev 1) Southern Industrial Area MW-123 (Installed after LTP Rev 1) Northern Industrial Area MW-124 (Installed after LTP Rev 1) Northern Industrial Area Supply Well B Central Peninsula The attached Figure 5-3 illustrates the capture zones for those monitoring wells listed above located in the industrial area and vicinity along with other monitoring wells in the eastern industrial area that have shown detections of radiological contamination (MW-1 01 S/D, MW- 03S/D and MW- 02S/D). Although there are other monitoring wells more toward the center of the plume in this area that have shown detections, the monitoring wells illustrated in Figure 5-3 define the perimeter of the zone of influence for the industrial area and the upper peninsula. By reviewing these capture zones, the affected survey areas were determined for this portion of the site and are shown in Table I of this submittal. The attached Figure 5-3.1 illustrates the capture zones for the monitoring wells listed above that are located in the central peninsula area. As with Figure 5-3, these zones have been used to determine the survey areas for which groundwater dose impact needs to be considered. These survey areas are also listed in Table 1 of this submittal.

US NRC - Document Control Desk CY-05-022, Page 3 For the remaining monitoring wells outside the industrial area capture zone perimeter or not listed for the peninsula area, there have been no validated detections. Additional detail on groundwater monitoring results has been, and will continue to be, provided in the semi-annual groundwater monitoring reports submitted to the State of Connecticut DEP in support of the Phase 2 Hydrogeologic Work Plan. Copies of these reports will be provided to the NRC and EPA. As described in the HNP LTP, when CYAPCO requests release of a survey area from the NRC license, an evaluation will be included as to whether there is any groundwater dose impact. CYAPCO will continue to review the list of affected survey areas listed in Table 1 and provide updates to the NRC based on new groundwater characterization information as they occur. It should be noted that the following survey areas are currently listed In HNP LTP Table 5-3 as being affected by groundwater contamination but are not included in Table 1: 9104, 9108, 9110, 9112, 9114, 9116, 9118, 9120, 9126, 9128, and 9307. These survey areas were deleted during the recent update of the HNP LTP (August 2004 Update of the HNP LTP) but were left inadvertently in Table 5-

3. The HNP LTP has been revised to reflect the above described changes and the revised pages of the HNP LTP will be distributed to the controlled copy holders of the HNP LTP in the nearfuture.

Ifyou should have any questions regarding this information, please contact Mr. G. P. van Noordennen at (860) 267-3938. Sincerely, Signed by G. Bouchard 1/31105 G. H. Bouchard Date Director Nuclear Safety/Regulatory Affairs : Estimated Zone of Influence/Capture Zone for Hypothetical Water Supply Well in Post-Closure Dose Modeling cc: S. J. Collins, NRC Region 1 Administrator T. B. Smith, NRC Project Manager, Haddam Neck Plant R. R. Bellamy, Chief, Decommissioning and Laboratory Branch, NRC Regionl

US NRC - Document Control Desk CY-05-022, Page 4 E. L.Wilds, Jr., Director, CT DEP Monitoring and Radiation Division P. Hill, CT DEP M. Rosenstein, US EPA, Region 1

US NRC - Document Control Desk CY-05-022, Page 5 Table 1 Survey Areas Affected by Groundwater Contamination (All Survey Units Unless Otherwise Noted) Survev Area 1000 9306 9522 2000 9308 9527 3000 9310 9528(Units 0,2 &3) 4000 9312 9530 (Units 1,2,3 & 5000 9313 4) 6000 9502 9801 9102 9512 9802 9106 9514 9803 9226 9518 9804 9302 9520 9805 9304 9521

0 - Wdlmdon Notes GRAPHIC SCALE M I I I Ago-, Connecticut Yankee Atomic Power Company CaptureZone PerimeterforAffected Monitoring Wells

 . CY in the IndustialArea and UpperPeninsula,,

?8_0000 octerradius Not-AM. 11 7S a-000 GRAPMC SCALE DFnr?) Connecticut Captum in the CentralPeninsuk Zone PerlincterforAPi!ctodMOnitOriDg'Wefls Yankee A tonuc PowerCompany Wev

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Docket No. 50-213 CY-05-022 Attachment 1 Haddam Neck Plant Ucense Termination Plan Supplemental Information - Survey Areas Potentially Affected by Groundwater Contamination and Capture Zone Analysis Estimated Zone of Influence/Capture Zone for Hypothetical Water SupplV Wells in Post-Closure Dose modeling January 2005

TECHNICAL MEMORANDUM Estimated Zone of Influence/Captuxe Zone for Hypothetical Water Supply Wells in Post-Closure Dose Modeling PREPARE FOR: Mr. Terry Peacock, Connecticut Yankee Atomic Power Company PREAO BY: Chuck Miller, CH2M HILL (> i - COPES: Mr. Rich McGrath, CYAPCO CH2M HMLL Project File DATE: January, 11, 2005 Introduction This technical memorandum describes the analysis of site groundwater characteristics at ConnecticutYankee Atomic Power Company's (CYAPCQ) Haddam Neck Plant (HNP) nuclear power station to develop estimated zones of influence, or capture zones, for hypothetical water supply wells at the plant The hypothetical water supply wells are part of the post-closure dose estimate modelingfor the resident fanner scenario performed to determine compliance with Nuclear Regulatory Commission (NRC) license termination criteria. The capture zone assessment was performed after obtaining results from on-site hydrogeologic testing and studies. These studies include stratigraplic analyses based on geologic logs generated during soil borings for foundation studies and during water supply well and groundwater monitoring well drling atthe facility. Hydrogeologic testing at the site includes long-term water level monitoring in 29 wells on-site and the Connecticut River; performing a pumping test in the unconfined aquifer; and performing packer test pumping in discrete intervals and open-borehole pumpingin deep bedrock boreholes. Groundwater at the HNP is found in both a shallow unconfined and possible send-confined aquifer within the unconsolidated alluvium and in confined and semi-confined aquifer units within the underlying fractured crystalline bedrock The unconfined aquifer is expected to exhubit a generally-isotropic capture zone, except where affected by boundary effects, with a radius that is directly proportional to the pumping rate applied to a water supply well. The aquifer pumping test results indicate a capture zone radius for the unconfined aquifer rangingfrom less than 30 feet at a pumping rate of 0.5 gallons per minute, to approximately 200 feet at a pumping rate of 29 gallons per minute. The fractured bedrock aquifer exhibits highly variable and directional (ie., anisotropic) capture zone effects that are dependent on both pumping rates and interception of

ESTIMATED ZONE OF INFLUEENCEICAPTURE ZONE FOR HYPOTHETICAL WATER SUPPLY WELLS INPOST-CLOSURE DOSE MOGEING transmissive fractures by the borehole. Open borehole pumping tests at HNP revealed hydaulic connectivity ranging from 185 to 462 feet in transndssive near-horizontal fracture sets at open-borehole pumping rates of 1.9 and 6.7 gallons per minute, respectively. Hydrogeologic Measurements The capture zone analysis is supported by two sets of hydrologic measurements collected as part of hydrogeologic characterization of theHNP site. These measurement sets are pumping operations supporting bedrock characterization activities and a shallow unconfined aquifer pumping test. Results of these tests are discussed in the following subsections. Bedrock Pumping Activities Characterization of the fractured bedrock aquifer was performed through packer testing in one open bedrock borehole (borehole BH-121A) and HydrophysicalTm logging performed in four open bedrock boreholes (boreholes BH-118A, BH-119, BH-120, and B H-121A). Groundwater elevation hydrographs for 29 monitoring wells were evaluated during the bedrock pumping activities to identify pressure transients related to pumping events. Results of the open borehole pumping are used in this capture zone analysis because open borehle construction is considered to be representative of the hypothetical water supply well Details of the bedrock pumping activities are described in the Connecticut Yankee Atomic Power CogManv HaddainNeck Plant Task 2 Supplemental CharacterizationReport (CH2M HELL, 2004a). These tests include both discrete-interval pumping using an instrumented straddle packer assembly and open-borehole pumping performed as part of HydrophysicalTm logging of four boreholes. Locations of the bedrockboreholes and the surrounding transducer/data logger-equipped monitoring wells are shown in Figure 1. The anisotropic nature of distant hydraulic responses in the fractured bedrock system is illustrated in Figure 2 (observed responses to open-borehole pumping). The magnitudes of the distant responses to the bedrock pumping events are shown in Table 1. The bedrock pumping activities were short duration activities (e g., generally more than 8 hours, but less than 12 hours duration) and the hydrographs for distant well responses indicated non-equilibrium conditions (ie., drawdown curves were not asymptotic). Unconfined Aquifer Pumping Tests Characterization of the shallow unconfined aquifer was performed through a variable-rate step-drawdown test followed by a seventy-two hour constant-rate pumping test performed in a test well (well AT-1) located in the northwestern portion of the HNP industrial area. The test well was screened across the saturated thickness of the unconfined aquifer in the test study area and completely within the unconsolidated materials. Groundwater elevation hydrographs for surrounding wells were evaluated for test-related pressure responses.

ESTIMATED ZMNE OF INFLUENCEICAPTURE ZONE FOR HYPOTHETICAL WATER SUPPLY WLLS INPOST-OSURE COSE VOCEUNG Details of the unconfined aqufier pumping tests are described in the Connecticut Ynnkee Atomic PotoerComnany Haddacn Neck Plant Task 2 Supplemenfal Characderization Report (CH2M HJLL, 2004a) and Technical Memorandum- Results of the Uncontfined Aquifer Pumping Test Conductedin the IndustrialArea of the Haddam Neck Plant,East Hampton. Conncticut (CH2M ILL, 2004b). The test, or production, well and surrounding observation wells that indicated hydraulic responses are shown in Figure 3. Drawdown responses observed in monitoring wells during the step-drawdown test and the constant-rate pumping test are shown in Figures 4 and 5, respectively. The magnitudes of distance drawdown responses to the unconfined aquifer pumping are shown in Table 2. Extrapolation of Test Measurements and Observations to the HNP Site The pumping test measurements from the unconfined, confined and semi-confined units are considered sufficiently-representative of hydrogeologic conditions to allow their application for a broader assessment of the apparent capture zones. Pumping test activities have included distance-drawdown responses to groundwater pumping at nearly the rate used for post-closure dose modeling (Le., 0.45 gallons per minute). Measurement results expanded to areas beyond those actually tested, however, requires defining assumptions and identifying the apparent range of uncertainty applicable to the extrapolation. Thefollowing discussion sunmarizes the HNPhydrogeologic conceptual site model, describes dividing the HNP site into areas of similar hydrogeologic properties, and explains the applicability of the capture zones to those areas. HNP Hydrogeologic Conceptual Site Model The groundwater aquifer system at HNP includes the following features:

• A shallow unconfined aquifer system found in generally-sandy unconsolidated alluvial deposits of varying thickness and engineered fill surrounding plant structures. The shallow unconfined aquifer maybe hydraulically connected t othe shallow bedrock in '

some areas.

• Confined and semi-confined (i e., 'leaky") aquifer systems in fractured bedrock underlying the unconsolidated deposits. The fracturedbedrock is encountered at varying depths below ground surface and the bedrock aquifer exuhbits varying degrees of confinement. Bedrock aquifer tranunissivity is largely controlled by fracture sets oriented in a generally north-south direction.
• The Connecticut River is adjacent to the site and serves as a groundwater discharge boundary for the aquifer system (confined, semi-confined and unconfined aquifers).
• Groundwater beneath HNP is recharged by local infiltration of precipitation and surface water percolation and by infiltration of precipitation in the upland areas to the north of the power station area, inland of the river.

ESTIMATED ZONE OF INFLUENCEJCAPTURE ZONE FOR WPOTHETICAL WATER SUPPLY WELLS INFOSTCLOSURE DOSE MODELNG Additional discussion of the HNP hydrogeologic conceptual site model is found in the ConnecticutYankee Atomic Power CoMpan p Haddyn Neck PlantPhase2 Hvdrogeologic CharacterizationWork Plant Task I Summnun Report (CH2M HIL, 2004c). HNP Capture Zone Functional Areas The HNP site was divided into three similar functional areas for the capture zone assessment, as shown in Figure 6. The following areas of the HNP site have been identified as comparable to the hydrogeologic test areas based on structural similarity and hydrostratigraphic features:

• The BNP central industrial area. This area includes all of the primary power station structures (e.g., reactor containment, primary auxiliary building, fuel building, service and control buildings, and turbine building) and hydrogeologically consists of a relatively thin layer of alluvial deposits and construction fill overlying a thick fractured crystalline bedrock formation that is encountered relatively shallow below ground surface. Groundwater in this area exhibits varying degrees of plant-related contamination. This area is part of the river terrace of the HNP adjacent to the Connecticut River. The unconsolidated formation generally lies in direct contact with the bedrock in this area and appears to be in communication with semi-confined bedrock sytems. Based on observations during dewatering activities to support structure demolition, it is likely that the unconfined aquifer overlying the bedrock in the central portion of this area will not sustain long-term pumping and may become dewatered. Seasonal variations in local recharge will result in variable amounts of available groundwater in this area.
• The HNP parking lot and peninsula area. This area includes the administrationbuildng, parking lot, warehouse areas and the EOF on the northern portion (relative to plant north) of the river terrace area. It also includes the discharge canal peninsula to the south of the industrial area, the discharge canal itself, and the river terrace inland of the discharge canal extending to the southern property boundary near the Salmon River.

This area consists of a relatively thicklayer of unconsolidated alluvial and overbank deposits overlying crystalline bedrock. The unconsolidated formation is separated from the bedrock by a dense layer of sand, silt, and gravel that is interpreted as glacial till and exhibits low transmisivity. Although the shalow unconsolidated aquifer in these areas is in communication with the aquifer underlying the industrial area, the predominant groundwater flow (i e., northeast to southwest) tends to minimize the distribution of contaminants from the industrial arealaterally into these areas. Theupperpensinsula (i.e., the area immediately adjacent to the industrial area) exhibits some groundwater contamination that appears continuous with that underlying the industrial area The lower peninsula (ie., the southern portion of the peninsula extending from the current waste storage area to the southern terminus of the peninsula at the mouth of the discharge canal) is in hydraulic communication with both the discharge canal and the Connecticut River. There are no defineable contaminant plumes present in the lower peninsula and observed contaminant concentrations do not exceed closure criteria.

• The HNP upland area. This is the largest part of the HNP and consists of steeply-slopingupland area to the east (relative to plant north) of the river terrace. It includes the Independent Spent Fuel Storage Installation (ISFSI) and the former HNP landfill

ESTIMATEDZONE OF INFLUENCEICAPTUREZONE FOR HYPOTHEJICALWATER SUPPLY WaL NPOST-CLOSURE DOSE MODEUNG area. The upland area consists primarily of discontinuous veneers of soil overlying crystalline bedrock The landfill area near the southern end of the upland area exhibits a relatively thick sandy surface deposit No groundwater contamination is found in this area. The groundwater in the upland area is in hydraulic communication with the industrial area and the parking lot area via local recharge into the unconsolidated aquifer and through flow of groundwater within the underlying fractured bedrock.

• The capture zone dimensions applicable to these functional areas are shown in Table 3. The estimated water supply well capture zones for these areas depend on the following site-specific conditions:
• The aquifer being pumped (ie., shallow unconfined or bedrock);
• The pumping rate applied to the well;
• The total depth of the well; and
• Interception of specific transmissive fracture sets in the bedrock aquifer.
• Degree of communication between semi-confined units and overlying unconfined units.

Variability of site-specific conditions within each functional area leads to uncertainty in the exact radius of well capture zones. The assumptions used to identify the capture zone radii and apparent uncertainties are also described in Table 3. Application of Capture Zone Assessment to HNP Post-Closure Dose Modeling for the Resident Farmer Scenario The HNP license termination plan (LTP) establishes a plume influence boundary at a distance of one-hundred meters from the groundwater contamination plume within the industrial area The contamination plume is defined as the 1,000 pCi/L plume contour of tritium in groundwater. Post-closure dose estimate modeling assumes the hypothetical water supply well would not capture site-related groundwater contaminants if installed alongthatboundary. The LTP states thatif the capture zone is determined to be greater than one hundred meters, then NRC will be notified. The empirical test measurements used to support determination of the well capture zone are described below. Unconfined Aquifer Pumping Test Results For wells completed in the shallow unconfined aquifer, the capture zone of a well pumped at 0.5 gpm was less than 30 feet (<10 meters). This determination is based on the 0.5 gpm portion of the step-drawdown test performed prior to the constant-rate aquifer pumping test conducted in the unconfined aquifer. The test was conducted in a five-inch diameter well that was screened over the entire thickness of the unconfnined aquifer. A near-field monitoring well located 29 feet from the pumping well was equipped with a data-logging pressure transducer to record near-field effects. No response was observed in the near-field monitoring well during the 0.5 gpm pumping activity.

ESTIMED ZONE OF INFLUENCE APTUREZONEFORHYPOTHETICALWATER SUPLY WELLS INPOST-OSURE DOSE MODEUNG The results of the seventy-two hour constant rate pumping test provide a good upper-level bounding estimate of capture zone in the unconsolidated formation. The test well was pumped at 29 gpm, and at the end of the test period a drawdown response was observed in the near-field monitoring well at 29 feet (8.6 m) from the pumping well and in the next nearest monitoring well at a distance of 100 feet (30 m). A possible hydraulic response (ie., a dbwnward inflection in the distant well hydrographs late in the pumping test period) attributable to the pumping test was observed in two wells 190 feet (58 m) from the pumping well, delineating a probable maximum capture zone of approximately 200 feet (61 meters) at a pumping rate of 29 gallons per minute in the unconsolidated materials of the shallow unconfined aquifer. Based on these observations, the capture zone of a hypothetical water supply well completed in the unconfined aquifer is less than the 100 meters stipulated in the post-closure dose model. Based on the similarity of the unconsolidated materials across the site, the capture zone for a hypothetical water supply well under the modeled conditions (ie., 0.46 gpm) canbe assumed tobeless thantenmeters. Thecapturezone shouldbe assumedto extend unifomldy in all directions around the hypothetical water supply well. Confined AquiferlFractured Bedrock Pumping Test Results For wells completed in bedrock boreholes that intersect transmissive fractures, pumping from an openborehole is identified as the most representative test measurement for this assessient.- Open borehole pumping was conducted during characterization of bedrock hydraulic properties at the site during 2004. Pumping was conducted at various rates in four boreholes. Hydraulic responses were observed in distant wells equipped with data-logging pressure transducers and were evaluated to confirm that the responses were related to the pumping activities. The open borehole capture zone was observed to range from 185 feet (56 meters) at a pumping rate of 1.9 gpm to 462 feet (141 meters) at a pumping rate of 6.7 gpm. Based on these observations, the capture zone for a hypothetical water supply well completedin fractured bedrock and pumped at the modeled conditions (ie., 0.46 gpm) is less than the 100 meters evaluated in the post-closure dose model. This estimate is based on the observation that pumping an open bedrock borehole at a rate approximatelyfour times the modeled rate (e.g., 1.9 gpm vs. OA6 gpm) produced an observed maximum capture zone of only 56 meters. The open boreholes used for the borehole pumping tests were cased from the ground surface to the top of bedrock and are consistent with the expected design of a bedrock water supply well as typically constructed near the site. The containment foundation mat sump and other dewatering activities were active during the bedrock pumping. Although this distant extractionmayhave reduced the observedmagnitude of distant drawdown responses, it is not expected to have substantially reduced the observed radius of influence.

nu loo Can t= Esmp+ Locaton of Bomhole Notes: (1)Transducer locations are approximate locations FIGURE 1 (2) Base map obtained from Malcolm Plmle, April 2002 LOCATION OF WATEr-R LEVEL TRANSDUCERS AND BOREHOLES CH2EVIHILL HADDAM NECK PLANT (HNP)

4% ROA. & PARM.O ... J SURFfle!

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MOTORMG I5 WRING 1OVM¶NGRESPONSE 7OUING IN WRMcK BORBMOEM 121

Table 1. Location and Magnitude of Responses to Bedrock Pumping Events in Open Boreholes. Drawdown in Well Distance from Location rumping Rate Pumping Exhibiting Pumping Observed 1cat10ft Well Response Wef BH-TI8A 5 gpm. 4.8 ft MW-106D 185 ft 0.45 UH-118A 31 gpm 78 ft MW-106D 185 ft 1.10 ft BH-119 1.4 gpxn 21 ft MW-109D 185 ft 0.1 ft BH-120 1.9 gpm 16 ft MW-109D 28 ft 1.4 ft MW-11OD 74ft 1.1 ft BH-121A 6.7 gpm 37 ft MW-107D 333 ft 0.1 ft MW-2D 462 ft 0.6 ft

14 G>r

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Figure 4 Step Drawdown Test Response in AT-I and OB-25 September 2004 OB.25 Drawdown (ft) AT-1 Di 1.3 1 AT-1 l- -- - -- OB-2E Time

Figure 5. Drawdown Responses During Constant Rate Pumping Test. AT-1 Pumping Test: AT-I Results Corrected Drawdown versus Elapsed Time (BE.- 11.7%) Mapod rnti t 1D 100 low gIss - _ _ _- I ' II!I I !111 E 'I _ ___P I_ I 02.00 - _ ~~

                 =^wIII-> X I1~                          11!r 1            !t1'x1___1 AT-1 Pumping Test. OB-25 Results Corrected Drawdown versus Elapsed Time (Be 11J7%1)

Elnpwd Tnm(iwaaj I 10 100 1000

          -.           r'             1I'hlUi 4               I Ij II                IIIlli I
          - Ii-igz                 H           HL I O                               L Ii  I I Iii

ESTIMATED ZONE OF INFWENCEICAPTURE ZONE FOR HYPOTHETICAL WATER SUPPLY WELLS INPOST-CLOSURE DOSE MODEUNG AT-1 Pumping TesL MWI 24S Results Corrected Drawdown versus Elapsed Time apsE11.7%e) El1 Th" UNZe I eIIIx' ITll to i! 1ce 1I 1 1 11!1 Ii DD . -- --- ' Ili I_1l I I !111! £ 0.*1 IM11! 13 , !11  !!11!  ! !1

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Table 2. Location and Magnitude of Responses to Unconfined Aquifer Ptmuping Events. Pmig Drawdowan.i Well Exhdibiting Distance from Drawdown Observed Punnpinglocation lRtie(gpr)l Pumpl g Well Response (PfpingWell (feet) Rae(p)(feet) (fpgell) AT-I (Step-drawdown 0.5 0.05 OB-25 29 0 test observations at the end of each 1-hour 10 0.5 OB-25 29 0.1 duration step) 15 0.85 0-25 29 0.18 29 1.5 OB-25 29 0.32 AT-1 (Final drawdown _01-25 29 1.95 at end of 72-hour constantrate pumping 29 325 100 1.5 test) MW-109D 190 Inflection response only* MW-508D 190 Inflection response only*

• Note: No measureable drawdown response was observed in hydrographs for these two wells, however, a downward inflection the hydrograph of each wells was observed late In the constant rate pumping testperiod.

WJG - -.- PO_._ Ws E N FIGURE 6 XL soWA HNP CAPTURE ZONE FUNCTIONAL AREAS CH2MHILL 27feO4.CY SheA Maoof HNP

                      '      A-               '                     HADDAM NECK, CT

ESTMTED ZONE OF LUEN CAPil7M ZONE FOR HYPOTHElICAL WATER SMPPLY WElLS INPOST-CLOSURE DOSE MODELING Table 3. Capture Zone Dimensions Applied to Functional Areas. Unconsolidated Bedrock Functional Formation Pumping Formation Pumping Uncertainties and Area Capture Zone Rate Capture Zone Rate Applicable Assumptions Radius (gpm) Radius (gpm) Commens (feeVmeters) (fee/meters) HNP lndustrial c30ft/c10Om 0.5 c 200 ft/< 62m 0.5 a. Unconflnedaqulferwell(s) are completed a. Theunconfinedlaquiferln Area above the bedrockinterface, the central portion of this area may not sustain this pumping

b. BedrockCwells are cased from surface to rate over time and may bedrock and open hole below. become dewatered.

c. The pumping rate i applied on a continuous b. Ihe magniltude of observed basds. hydraulic responses in distant bedrock wells may be affected by operation of the containment mat sump.

RiverTerace 'c30ft/< OM Oc200ft/c62m 0.5 0.5 a. Unconfined aquifer well(s) are completed (Parkinglot and above the bedrock Interfce. Peninsula)

b. Bedrock wells are cased from surface to bedrock and open hole below.

c. The pumping rate i5 applied ona continuous basis.

UplandArea <30ft/c10 m 0.5 <200ft/c62m 0.5 a. Unconfined aquliferwell(s) arecompleted a. Wlth the exception of the (Including ISPSI above the bedrock interface. landfil' vlcinltyS,most of the and landfill) upland area exhibits only a

b. Bedrock wells are cased from surfice to very thin veneer of bedrock and open hole below. uncnsolidatedaterial over

c. The pumping rate Is applied on a continuous bedroek thus precluding basis. In the unconfined aquifer.

Notes: '< - ess Than gpm gallons per minute

CY-HP-0193 Attachment 2 Haddam Neck Plant Survey Units in the Capture Zone Radius of Survey Area 9520-003

Connecticut Yankee Atomic PowerCompany Survey Unitsin the CaptureZone Radius ofSurvey Area 9520-0003

CY-HP-0193 Attachment 3 Haddam Neck Plant Connecticut Yankee Haddam Neck Plant Peninsula Groundwater Assessment

TECHNICAL MEMORANDUM GH2MHILL Connecticut Yankee Haddam Neck Plant Peninsula Groundwater Assessment PREPARED FOR: Mr. Terry Peacock, Connecticut Yankee Atomic Power Company PREPARED BY: Chuck Miller, CH2M HILL COPIES: Mr. Rich McGrath, CYAPCO CHI-2M HILL Project File DATE: February 8, 2005 I Introduction Tlhs document is a compilation and interpretation of the information collected to date on the nature and extent of radiological groundwater contamination on the discharge canal peninsula at the Connecticut Yankee Atomic Power Company (CYAPCO) Haddam Neck Plant (HNP) and potential sources for that contamination. Strontium 90 (Sr-90) has been detected at low concentrations in monitoring well MW-117 during three of the last nine sampling rounds. No specific source of the observed Sr-90 has previously been identified and the detections in MW-117 do not appear to be part of a larger contaminant plume. The purpose of this study is to evaluate the nature and extent of groundwater contamination on the peninsula, including the Sr-90 detected in MW-117, and determine if there is an apparent source. There have been periodic detections of other radionuclides in groundwater samples collected from monitoring wells on the peninsula. With a few exceptions (as discussed in the following sections of this report) historic concentrations of radionuclides detected in groundwater in the peninsula area are very low. The locations of detection of radionuclides are, for the most part, isolated spatially and temporally. This document summarizes the available groundwater and soil data, and evaluates apparent sources of the radionuclides observed in groundwater. The following conclusions are based on the assessment described in this document:

• The activity concentrations of radionuclides and radioactive indicators (e.g., gross alpha and gross beta activity) detected in groundwater on the upper and lower peninsula do not exceed the most stringent water quality standards selected for assessment of plant closure (ie., Maximum Contaminant Levels established as drinking water standards).
• Radionuclides detected in groundwater in the upper peninsula (i.e., the "boneyard" area) appear to be related to downgradientmigration of plant-related contaminants from historical activities in the central industrial area (ie., nuclides detected in MW-11OS and MW-11OD) and local activities in the boneyard (i.e., waste water discharges to the PAGE 1OF21

plant sanitary septic system) that may have historically affected wells MW-lllS, hmW-112S, and MW-113S.

• Concentrations of plant-related contaminants in groundwater in the upper peninsula wells, particularly in the area of wells MW-1105, MW-1OD, and the new bedrock well MW-121A are expected to vary in the near future as the plume of contaminants originating in the central industrial area continues to migrate toward this area.
• Radionuclides detected in groundwater in the lower peninsula area are present at low concentrations and do not appear to represent a "plume" of contamination related to a single source. The most likely sources of the observed radionuclides in groundwater in the lower peninsula are 1) episodic migration of low activity concentration process water historically discharged to the canal and drawn into the peninsula formation by either hydraulic head difference between the canal and the Connecticut River or the hydraulic capture of water by operation of the plant sanitary water supply wells; and 2) leaching of nuclides from low-activity concentration dredge spoils that were historically removed from the discharge canal and placed on the lower peninsula.
• Contaminant concentrations are expected to continue to diminish in the lower peninsula area and detections to become less frequent. No mechanisms have been identified that would cause the concentration of plant-related contaminants in groundwater to increase beyond their presentlevels in the lower peninsula. The sanitary water supply wells will be removed from service within the next 24 months and all plant-related water discharges to the canal will also be discontinued in the same time frame. The residual radioisotopes present in soil on the lower peninsula are not expected to contribute to either an increase in groundwater concentrations or increased frequency of detection of radionuclides. No additional characterization of groundwater or potential sources in the lower peninsula is indicated based on the results of this assessment.

2 Background The area that now forms the peninsula was part of the property developed for use as a private airport in the 1940s. The runway ran approximately parallel to the current orientation of the peninsula, extending from the current location of the industrial area to near the position of the dredge spoil coffer-dam area on the peninsula (Figure 1). The CYAPCO nuclear power station was constructed, and the cooling water discharge canal was excavated between 1964 and 1967, separating the peninsula from the mainland. The canal is approximately 5,550 feet long. The elevation of the bottom of the canal is approximately minus six feet mean sea level (msl) (Mactec, June 2004). The peninsula ground level elevation varies from 8 tolWfeet msl, with higher elevations near the tip where material appears to have been piled, along the edge adjacent to the canal, at water supply wells TPW-1 and TPW-2, and around the dredge spoil coffer-dam area (Figure 1). 2.1 Peninsula Wells Numerous groundwater wells are located on the peninsula. These include the following types of wells: supply wells providing sanitary and process water to HNP; PAGE 2 OF 21 8FEBO5.YENINSULA GY EVALUATION-CWM

• testwells installed as part of a previous water supply exploration; and
• groundwater monitoring wells that are part of the groundwater monitoring system.

The wells on the peninsula are discussed below. Water Supply Wells Water supply wells A and B were installed on the peninsula in 1963 (Figure 1) to supply sanitary water and process water for HNP. By 1984, the water supply wells were exhibiting elevated temperature, which dramatically reduced the utility of the water for process cooling functions. The elevated temperature was caused by capture of the heated water from the discharge canal due to the close proximity of the water supply wells to the canal and the high hydraulic conductivity of the aquifer. An investigation was undertaken to identify alternative water supply well locations (Leggette, Brashears & Graham, Inc., 1985). During the second half of 1984 and early 1985, 15 monitoring wells were installed on the peninsula in a water supply investigation. Following the exploration stage, two additional observation wells and two water supply wells (Wells C and D) were installed on the side of the peninsula nearest the Connecticut River. The replacement wells, however, exhibited elevated total dissolved solids and other water quality issues. The new water supply wells were removed from service and supply wells A and B were returned to service. The discharge canal water pulled into the peninsula by the operation of wells A and B is a potential source of groundwater contamination. Test Wells The wells identified as test wells are all located in the lower peninsula area and were installed as part of historical water supply investigations. Some were constructed at the time of initial plant construction, and others were constructed during the 1985 water supply exploration. Production wells A and B and a test well identified as Well 10-2 were part of the initial sanitary supply investigation. Monitoring wells MW-1 through MW-18, along with production wells TPW-1 and TPW-2 and Test Wells TW-1 through TW-4 were constructed during the 1985 water supply investigation. The "test wells" and monitoring wells MW-1 through MW-18 were inspected and found to be substandard and unacceptable for inclusion in the HNP groundwater monitoring system, although they apparently met the needs of the water supply investigations. Monitoring wells MW-5, -6, -7, -9, -10, -11, -12, -14, -15, -16, -17, and -18 were located on the most distal end of the peninsula and were abandoned in 2004. The remaining test wells and historical monitoring wells are also not acceptable for use in groundwater quality monitoring and will be abandoned. The four production wells will remain until the end of plant decommissioning. Groundwater Monitoring Wells Seven wells on the peninsula are part of the current HNP groundwater quality monitoring system. Monitoring wells MW-11OS and -11OD, MW-IllS, MW-112S, and MW-113S are all located in the upper peninsula area. Well MW-lllS was located in the midst of the four PAGE 3 OF21 EFEBC5.PENSULLA GW EVALUATaON-M

sanitary sand filter structures and was abandoned in 2004 prior to demolition of the filter structures. Wells MW-1125 and -113S are located adjacent to the sanitary leaching field. Wells MW-110S, and -11OD are part of the industrial area monitoring system. Shallow bedrock monitoring well MW-11OD has historically exhibited plant-related contamination that is attributed to downgradient migration of contaminants from the central HNP industrial area. MW-11OD is not included in this assessment. Two deep bedrock boreholes (BH-121 and BH-121A) are also located on the upper peninsula. Borehole 121A has been configured with a multi-level sampling device, however, the system is not yet in service and no historical monitoring data are available. Borehole 121 is not part of the monitoring system. The bedrock boreholes are not included in this assessment One well, MW-117, is located in the lower peninsula area, approximately midway along the length of the peninsula and approximately midway across the width. 2.2 Historic Land Use Activities The peninsula area of HNP is divided into the following two general areas of historical activities:

• The upper peninsula which extends approximately 1,300 feet from the industrial area south gate (relative to plant north). This area was used as a lay-down area for various materials during and after plant construction. The upper peninsula is also the site of the plant sewerage disposal facility, which includes septic tanks and lift stations, a series of four sand filters, and a septic leaching field. This area is commonly referred to as the "bone yard" and is currently used for staging of empty and filled waste containers. The following final status survey units comprise the upper peninsula: 9518-00, 9520-01, 9520-02, and 9520-03.
• The lowver peninsula incorporates the remainder of the peninsula and includes the location of the four sanitary water production wells, the numerous test wells associated with historical water supply explorations, and dredge spoil deposit areas. Construction debris of uncertain origin has also been deposited on the ground surface in some areas of the lower peninsula. Soil and sediment excavated during original construction of the BNP discharge canal were placed on the peninsula. In 1979,1500 cubic yards (yd3 ) of spoil was dredged from the discharge canal and 29,000 yd 3 of dredge material was removed from in front of the intake structure. Both spoils were allowed to settle out in the coffer-dam area on the peninsula (Figure 1). In 1984, the area on the river side of the intake structure was again dredged, and the material placed on the peninsula near the meteorological station. In 1987, additional sandy material was dredged from the canal and placed in the coffer-dam structure. At about the same time, some of the dredge material was removed from inside the coffer-dam settling area and placed on the outside edge of the structure widening the eastern coffer-dam of the settling basin (FSS, historical records). These dredged materials appear to extend across the location of monitoring well MW-117S. The dredged materials on the peninsula are potential sources for groundwater contamination. Over the operating life of the plant, additional construction debris was placed at various locations on the peninsula. On the north side of the peninsula, and adjacent to the canal, is a large wetland area that has been flooded PAGE 4 OF 21 BFEDC5-PENINSUIA GW EVALUATIMOtCWL

by the canal during some high tides while the plant was still operating. Characterization of this wetland is discussed in Section 5. Sediment from the discharge canal washed into this wetland area, and the soils underneath are potential sources of groundwater contamination. The following final status survey units comprise the lower peninsula area: 9530-01, 9530-02, 9530-03, 9530-04,9530-05, and 9531-00. 3 Geology and Hydrogeology of the Peninsula A hydrogeologic cross-section constructed across the lower peninsula area shows a heterogeneous sequence of clastic materials (fine-grained sand, silt, and clay) that do not correlate with the fluvial and glacial deposits defined in the industrial area (Figures 2 and 3). These materials are present near the confluence of the Salmon River and the Connecticut River and thicken away from the site. The unconsolidated deposits likely represent deltaic deposits associated with the Salmon River. Previously constructed cross-sections through the peninsula identify similar deposits (CH2M HELL, April 2004). Peninsula monitoring wells are constructed in the unconsolidated deposits overlying bedrock. The bedrock surface of the peninsula generally dips to the southeast. Pre-construction borings in the vicinity of MW4 encountered bedrock at 68 feet below mean sea level (bmsl). Closer to the river, at TW-2, bedrock was encountered at 96 feet bms], but was not encountered in TW-1 as deep as 124 feet bmsl. Groundwater elevations in the shallow unconsolidated deposits on the peninsula are tidally influenced, generally a few feet above mean sea level (insl) at high tide, and less than 1 foot msl at low tide. Transinissivities in formations in which TPW-1 and TPW-2 are screened have been measured at 25,000 to 57,000 gallons per day per foot (Leggette, Brashears & Graham, 1985). Water supply wells A and B are screened in sand and gravel deposits which are highly transnissive and hydraulically connected to the discharge canal. As a result, during plant operations, both of these water supply wells exhibited elevated temperature due to thermal contamination from capture of plant discharge water in the canal. This suggests that discharge water from the canal was moving into the aquifer formation of the peninsula, and with sufficient head differences in the canal and groundwater in the peninsula, may have been migrating through the peninsula in other locations as well. 4 Groundwater Analytical Data The results of groundwater sampling and analysis have been generated and documented under the HNP groundwater monitoring program. Historical published quarterly groundwater monitoring results at HNP from 1992 through 2004 were evaluated to determine the current conditions in both areas of the peninsula (i.e., upper and lower peninsula). Most reported detections of radionuclides in groundwater in peninsula area wells are very low, only slightly exceeding the reported minimum detectable concentrations (MDC). The methodology for evaluating the groundwater analytical data is described below. PAGE 5OF 21 8FEB 05.PENINSULA GW EVALUATION_-MA

4.1 Groundwater Assessment Methodology For the purposes of this assessment, a detectable concentration of a constituent of interest in groundwater is defined as a measured concentration exceeding the MDC for the analyte in the individual sample. This definition of detected constituents is consistent with the HNP License Termination Plan and is appropriate due to the MDlCs being established at a relatively small fraction of the applicable MCL or MCL equivalent concentrations for constituents of interest. The average of the actual laboratory-reported vIVDCs for individual beta- and photon-emnitting radionuclides are compared to the nuclide MCL equivalent concentrations in Table 4-1. The average MDCs for selected non-specific radioactivity measurements (i.e., gross alpha and gross beta) and mass-based total uranium measurements are compared to the applicable MCLs in Table 4-2. Table 4-1. Comparison of Required MDCs to MCL Equivalent Concentrations for HNP Beta- and Photon-Emitting Radionulicdes of Interest Subject to Dose-Based MCL. hlCL Equivalent Average Actual Average Actual MaC as a Radionulfcde Concentration Analyitcal MDCI Fraction of the MCL (pCi/L) (pCi/L) Equivalent Concentration Tritium 20,000 275 0.01 Carbon-14 2,0O 7.8 0.004 Manganese-54 300 4.1 0.001 Iron-55 2,000 83 0.004 Cobalt-60 100 3.8 0.04 Nickel-63 50 3.5 0.07 Strontium-90 8 0.87 0.11 Technetium-99 900 113 O.01 Cesium-134 80 3.7 0.05 Cesium-137 200 2.5 0.01 Europium-152 200 9.8 0.05 Europlum-154 60 12 0.2 Europium-15S 600 10.6 0.02 Plutonium-241 300 7.0 0.02 1- Average of the actual MDCs for samples In the peninsla groundwater analysis data seL As shown in Table 4-1, the average analytical MDCs for the beta- and photon-emitting nuclides in the peninsula groundwater data set are generally less than 5 percent of the MCL equivalent concentration, with the exception of Nickel-63 (7%), Strontium-90 (11%) and Europium-155 (20%). This indicates that excluding nuclide concentrations that do not exceed the MCL does not substantially affect the cumulative MCL estimate for these PAGE 6 OF 21 8 FEB5-PENINSUSA GI EVALUATIONWM

nuclides. The one exception is Europium-154, for which the MDC is a larger fraction of the MCL equivalent concentration (ie., 20 percent). This nuclide, however, is infrequently detected atHNP and has never been detected in groundwater samples collected from the peninsula area. Table 4-2. Comparison of Average MDCs to MCL Concentrations for Selected Non-Dose Based and Mass-Based MCLs. Average Actual Average Actual TVIDC as a Measurement MCI. Concentration Analytical ?vDCI FrctoncentraetMon Concentration Gross Alpha 15 pCi/L 1.3 pCi/L 0.09 Gross Beta 50 pCi/L 2.6 pCi/L 0.05 Total Uranium 30 ug/L 0.01 ug/L 0.0003 l-. Average of the actual MlDCs for samples in the peninsula groundwater analysis data set. The historical data set used in this analysis is presented in Appendix A. The observed concentrations of the detected radionuclides were compared to the maximum contaminant level (MCL) promulgated under the Federal Safe Drinldng Water Act and subsequently implemented by the State of Connecticut as the state's drinking water standards. Two types of MCLs are applicable to the radioactive constituents detected in HNP groundwater, a dose-based MCL applies to beta- and photon-emitting radionuclides and individual numerical limits apply to gross alpha and gross beta measurements as well as total uranium. The comparison to the dose-based MCLs for the individual beta- and photon-emitting nuclides was performed by dividing the observed concentration of regulated nuclides in each groundwater sample by the equivalent concentration for each nuclide (ie., the nuclide activity concentration that would result in exceeding the MCL if only that nuclide were present) and summing the individual fractions for each nuclide present in a sample. This "sum of fractions" was compared to a limit of 1.0, or unity, to determine whether or not the MCL was exceeded For the gross alpha and gross beta measurements, the measured concentrations were divided by the MCLs of 15 pCi/L and 50 pCi/L, respectively. The observed total uranium concentrations were divided by the total uranium MCL of 30 ug/L. In all three cases, the results were reported as a fraction of the MCL. 4.2 Groundwater Assessment Results The historical record of groundwater monitoring on the peninsula for 2003 through June 2004 contains a total of 78 detections of specific radionuclides and/or non-specific measurements (i.e., gross beta and gross alpha) in groundwater samples from the upper and lower peninsula areas. No radionuclide concentrations on the peninsula exceed MCLs. The data set used for the assessment presented in the technical memorandum has not been evaluated for the presence of positive bias in the laboratory analysis. As a result, some of the detections discussed herein may be identified as "false positives". Analysis of beta-PAGE 7OF 21 EFEB 05-PENINSULA GNEVALUATIONCM

emitting radionuclides (e.g., strontium-90, plutonium-241) by liquid scintillation counting is particularly sensitive to positive bias. Upper Peninsula (uboneyard") Assessment Sampling and analysis data were assessed for the following monitoring wells located in the upper peninsula or uboneyard" area:

• MW-IIOS
• MW-111 (well abandoned in 2004)
• MW-112
• MW-113 The radioactive constituents detected in groundwater samples from the upper peninsula wells are summarized and compared to MCLs in Tables 4-3 and 4-3 for beta/photon emitters and for other regulated radioactive constituents, respectively. The assessment indicates that radioactive constituents, including constituents attributed to plant-related sources have been detected in groundwater in the upper peninsula area. Previous assessment of groundwater in the upper peninsula indicates that contaminants observed in wells MW-1lOS and MW-111 are most likely part of a groundwater contaminant plume extending from the HNP central industrial area downgradient toward the Connecticut River. Historical operation of the sanitary septic system and septic sand filters in the upper peninsula may have also contributed to conditions observed in MIW-111. Wells MW-112 and MW-113 are likely impacted by historical waste water discharges to the existing sanitary waste leach field adjacent to the wells.

Table 4-3. Summary of Regulated Beta- and Photon-Emitting Radionuclides Detected in Upper Peninsula Monitoring Wells. Betafhoton- Activity Concentration Range Maximum MCL Sum-of-Well EmittingNudlides Fractions for Observed Detected (I'{p/L) Detections" hlW-110S Tritium 1,010 to 3,270 pCi/L (twelve detections) 0.17 Plutonium-241 6.9 to 132pCi/L (two detections) MW-111 Nickel 63 4.14 pCi/L (single detection) 0.08 MW-112 Strontium-90 5.49 pCi/L 0.69 (single detection) NW-113 Strontium-90 0.58 to 0.84 pCi/L aao I I (two detections) 0.10

-If the sum-of-fractions is equal to, or greater than, 1.0, then the MCL Is exceeded.

PAGE BOF 21 BFES 05FENINSUILA GW EVALUATIONCWM

Table 4-4. Summary of Other Regulated Radioactive Constituents Detected in Upper Peninsula Monitoring Wells. Radioactive Activity Concentration MCL Fraction at Maximum Well Constituents Range Detected (pCVL) Concentration' MW-IIOS Gross Alpha Not Detected NoDetected Gross Beta 1.88 to 7.47 pCi/L 0.15 (twelve detections) Total Uranium 0.01 ug/L Less than 0.01 (one detection) MW-111S Gross Alpha 0.68 to 1.0 pCi/L 0.07 (three detections) Gross Beta 3.24 to 7.39 pCi/L 0.15 (nine detections) Total Uranium 0.04 ug/L Less than 0.01 (one detection) MW-112S Gross Alpha Not Detected Not Detected Gross Beta 2.62 to 3.61 pCI/L 0.07 (two detections) Total Uranium 0.016 ug/L Less than 0.01 (single detection) MW-113S Gross Alpha 1.82 to 2.95 pCI/L 0.20 (two detections) Gross Beta 8.3 to 31A pCi/L 0.63 (nine detections) Total Uranium 0.072ug/L Less than 0.01 (one detection) I-If MCL fraction is equal to, or greater than, 1.0, then the MCL is exceeded. Lower Peninsula Area Assessment Historical groundwater sampling and analysis has been conducted for the following wells in the lower peninsula area:

• MW-1
• MW-2
• MW-3
• MW-13
• Supply Well B
• TW-1
• MW-117S PAGE 9OF 21 LFEB05-PEMNSULA GMEVALUATIONCVMA

The radioactive constituents detected in groundwater samples for the lower peninsula wells are summarized and compared to MICLs in Tables 4-5 and 4-6 for beta/photon emitters and for other regulated radioactive constituents, respectively. The assessment indicates that radioactive constituents, including constituents attributed to plant-related sources have been detected in groundwater in the lower peninsula area, but the observed concentrations do not appear to represent an organized contaminant plume and do not exceed drinking water standards. The observed groundwater gradient and flow direction in the vicinity of the HNP central industrial area does not support migration of groundwater from the industrial area to the lower peninsula. The operational history of the lower peninsula presents some possible sources for the groundwater contamination observed. These potential sources are:

• Episodic migration of low activity-concentration process water historically discharged to the canal and drawn into the peninsula formation by either hydraulic head difference between the canal and the Connecticut River or the hydraulic capture of water by operation of the plant sanitary water supply wells
• Leaching of nuclides from low-activity concentration dredge spoils that were historically removed from the discharge canal and placed on the lower peninsula.

Migration of water from the discharge canal and capture of water by the water supply wells appears to be the most likely source of groundwater contamination observed in the lower peninsula. Historic discharges contained variable concentrations of radioactive constituents and discharge water would be expected to readily migrate into the peninsula. The sanitary water supply wells were completed in a coarse, gravelly, formation in hydraulic connection with the canal and operated at substantial pumping rates. Direct capture of canal water was previously documented by the development of a thermal plume that reduced the utility of the supply wells for supplementary cooling water. The potential for contaminants leaching from dredge spoils to impact groundwater in the lower peninsula is discussed in Section 5 of this document. PAGE 10OF 21 0 FEB C5-PENINSULA GW EVALUATIOfJ.CWM

Table 4-5. Summary of Regulated Beta- and Photon-Emitting Radionuclides Detected in Lower Peninsula Monitoring Wells. Bets/Photon- Activity Concentration Range Maximum MCL Sum-of-Well Emitting Nudides Fractions for Observed Detected (PCVL) Detections" MW-1 None Detected None Detected None Detected MWI-2 Tritium 439 pCI/L (single detection) O04 Plutonium-241 112 pCi/L (single detection) MW-3 None Detected None Detected None Detected hIW-13 None Detected None Detected None Detected Supply Well B Strontium-90 1.02 pCI/L 0.13 (single detection) TW-1 None Detected None Detected None Detected MW-117S Strontium-90 0.76 to 1.42 pCi/L 0.18 (three detections) I - If the sum-of-fractions is equal to, or greater than, 1.0, then the MCL is exceeded. PAGE 11OF21 8FEB 05-PENINSULA GW EVALUATIONCWM

Table 4-6. Sumunary of Other Regulated Radioactive Constituents Detected in Lower Peninsula Monitoring Wells. Radioactive Activity Concentration Well Constiuents Range MCL Fraction at Maximum Detected (CL)Concentration MIW-IGross Alpha Not Detected Not Detected Gross Beta Not Detected Not Detected Total Uranium Not Analyzed Not Analyzed MW-2 Gross Alpha Not Detected Not Detected Gross Beta 2.75 to 4.43 pCi/L 0.09 (three detections) Total Uranium Not Analyzed Not Analyzed MW-3 Gross Alpha Not Detected Not Applicable Gross Beta Not Detected Not Detected Total Uranium NotAnalyzed Not Analyzed Mw-13 None Detected None Detected None Detected Supply Well B None Detected None Detected None Detected TW-1 None Detected None Detected None Detected MW-117S Gross Alpha 1.59 to 3.8 pCi/L 0.25 (two detections) Gross Beta 5.41 to 11.66 pCi/L 023 (nine detections) Total Uranium Not Detected Not Detected _- If MCL fraction Is equal to, or greater than, 1.0, then the MCL is exceeded. PAGE 12OF 21 8FEB 05-PENINSULA GN EVALIUATIONM

5 Soil and Sediment Analytical Data Soil and sediment analytical data generated during characterization of the lower peninsula were evaluated to assess the potential for soil and historically-deposited dredge spoils to act as sources of groundwater contamination. The methodology applied in the assessment and the results are presented in the following subsections. 5.1 Soil Assessment Methodology As part of site characterization and final status survey activities, soil samples have been collected at a number of locations on the peninsula, and sediment samples in the discharge canal. Sediment samples were collected at 77 locations in the discharge canal and analyzed for Sr-90 (a beta emitter), and gamma spectroscopy. Soil sampling locations on the peninsula are segregated into 5 final status survey units (Figure 4). FSS unit 9530-01 is a roughly triangular-shaped area bounded by roads in the western portion of the peninsula. FSS unit 9530-02 is the western half of the dredge spoil coffer dam area. FSS unit 9530-03 is the eastern half of the dredge spoil coffer dam area. FSS unit 9530-04 is the remainder of the middle portion of the peninsula with the exception of units 01, 02, 03, and 05. Area 5 is a 600 foot diameter partial circle on the canal edge of the large wetlands area in the northern central area of the peninsula. The southernmost portion of the lower peninsula is included in FSS unit 9531-00. To evaluate residual soil and dredge spoils on the peninsula as potential sources of groundwater contamination, it is necessary to quantify the potential for leaching of contaminants from the contaminated soil. For this assessment, an approach was developed that uses distribution coefficients (KdS) generated by Brookhaven National Laboratory (BNL) to support design of backfill material for HNP closure activities. Specimens of local fill soil were collected from a commercial'sand pit near the HNP and sent to BNL for determination of the Kds for selected nuclides. This material consists of locally-mined, well-graded, alluvial sand, also known as "bank run" sand. The material was tested to determine its capacity to sorb four nudlides of interest at HNP:

• Cobalt-60;
• Cesium-137;
• Strontium-90; and
• Iron-55.

The data generated from the backfill study was selected for use in this assessment because it was based on testing of soil from a similar depositional environment to that of the peninsula. The soil samples collected for the BNL Kd study are assumed to be sufficiently representative of the soil in the peninsula to allow approximation of the Kds of the peninsula soil. The distribution coefficients observed for the test soil (Brookhaven National Laboratory, 2004).were then applied to the soil samples collected from the HNP peninsula area to estimate the potential equilibrium water concentration resulting from contact of water with the soil. PAGE 13OF 21 8 FEB05.PEIINSULA GWELUATION-CWM

Distribution coefficients were determined for two soils (one slightly more coarse than the other) and for a mixture of the two soil types. This resulted in a high, low, and medium Kd for the selected nuclides. The distribution coefficient of a constituent of interest is defined as the concentration of the constituent sorbed onto the soil matrix divided by the concentration of the constituent remaining in solution at equilibrium conditions as described in the following equation: Csau Kd '- Csoln Where: Kd = the distribution coefficient C = the equilibrium concentration of the constituent of interest on soil C =olnthe equilibrium concentration of the constituent of interest in solution. For this assessment, an arbitrary soil screening concentration was developed using the Kd s for selected nuclides generated by the BNL study and using the MCL equivalent concentration for the selected nuclides as the equilibrium solution concentration and solving the distribution coefficient equation for the equilibrium soil concentration. The equilibrium soil concentration was then used as a screening concentration to determine if the observed soil concentrations could result in equilibrium groundwater concentration that would meet the MCL. The soil screening concentration was determined as follows: C5samC = Kd X CMCL X 0.001 Where: Kd = the distribution coefficient in units of mL/g Coon,= the soil screening concentration of the nuclide of interest in soil in units of pCi/g CMa = the MCL equivalent concentration of the nuclide of interest in water in units of pCi/L The analytical results for soil samples collected from the peninsula were then compared to the soil screening concentrations to evaluate the potential for the existing soil to cause exceedence of the MCL in groundwater. The following simplifying assumptions are applied to the analysis:

• The distribution coefficients developed for the backfill material are representative of the soil in the peninsula.
• The contaminated soil would actually reach an equilibrium condition with water in a saturated state.

The soil screening concentrations derived from this exercise are shown in Table 5-1. The measured radionuclide concentrations in soil samples from the peninsula were subsequently compared to the soil screening concentrations to estimate whether or not the observed soil could be expected to cause exceedence of the MCL As previously described PAGE 14 OF21 BFES S-PENMNSULAGW EVALLIATIMONCWM

for the groundwater analytical results, soil analyses were assumed to be detections if the reported result exceeds the reported laboratory MDC for the sample. Table 5-1. Soil Screening Concentrations for Peninsula Groundwater Assessment. Radionuclide Estimated Estimated Kd Value' Kd Values Kd Value' MCL Soil Screening Soil Screening Radionuclide Soil A Soil B Mixed Soil Equivalent Concentration Concentration (mL/g) (mL/g) (mL/g) ConcentrationI -igh -Low I_(pCi/L) (pCi/g) (pC1/g) Cobalt-60 2 220 22 100 22 0.2 Cesium-137 23 149 45 200 29.8 4.6 Strontium-90 i5 10 44 8 035 0.08 Iron-55 160 1200 1200 2000 2400 320 l - Ki Values determined experimentally by Brookhaven National Laboratory on local vendor bank-run sand. 2- MCL Equivalent Concentration is the concentration of a single nuclide which, if present in water, would meet the MCL. The comparison of observed soil concentrations to the calculated soil screening concentrations provides a basis for evaluating the potential for residual soil to cause groundwater to exceed the MCL. A second calculation was also performed to estimate the equilibrium groundwater concentration using the measured soil nuclide concentrations and the distribution coefficients established in the BNL backfill study using the following equation: CSou CCW - X 1000 Kd Where: Kd = the distribution coefficient of the nudlide of interest in units of mL/g Cu = the measured concentration of the nuclide of interest in soil in units of pCi/g Crw = the estimated equilibrium concentration of the nuclide of interest in water in units of pCi/L The results of the estimated groundwater concentration calculation were then compared to the actual measured groundwater concentrations. 5.2 Soil Assessment Results Soil analytical results for the four nuclides for which I&s were established (i.e., Co-60, Cs-137, Sr-90, and Fe-55) were evaluated and compared to the soil screening concentrations. The soil analytical data used in this assessment are presented in Appendix A of this PAGE15OF21 8 FES 05J'ENINSULA GWEVALUATION-CWM

technical memorandunL Tlhe results of the assessment of soil concentrations in the individual FSS units of the peninsula, as well as discharge canal sediments, are discussed below and are summarized in Table 5-2. Table 5-2. Comparison of Summary Peninsula Final Status Survey Unit Soil Concentrations to Calculated Soil Screening Concentrations. Unit 9530-1 Unit 9530-02 Unit 9530-03 Unit 9530-04 Unit 9530-05 Unit 9610 Maximum Maximum Maxnmum Mlaxijmum imum Maximum Detected Soil Detected Soil Detected Soil DetectedSoil Dctected Soil Detected rodlonucilde Concentration Concentration Concentration Concentration Concentration Concent Exceeds Soil Exceeds Soil Exceeds Soil Exceeds Soil Exceeds Soil E needt on Screening Screening Screening Screening Screening Eceedin Concentration? Concentration? Concentration? Concentration? Concentration? Scening Cobalt.60 Low - No Low - No Low - No Low - No Low3 - Yes Low2 - Yes High - No High - No High - No Hgh - No High - No High - No Strontium-90 Low - No Low - No Low - No Low - No Low - Yes Low' - Yes High-No High - No High-No High - No High - No High - No Iron-55 Low - No Low - No Low - No Low - No Low' - No Low' - No High-No High - No High-No High - No High - No High-No Cesiurn-137 Low - No Low - No Low - No Low - No Low: - No Low' - Yes High - No High - No High - No High - No High - No High - No

'"HighKW and 'Low K.? soil screening concentrations for these four nuclides are defined In Table 5-1.

1 The "Low &V soil screening concentration Is not expected to be representative of the fine-textured canal sediments or organic welland soDs. PAGE 16 OF 21 8FEB 05-PENINSUILA GWEVALtIATION-CW1A

In summary, the observed soil and sediment concentrations of nuclides detected in soil samples collected from the lower peninsula could account for the low concentrations of strontium-90 historically detected in wells on the peninsula. The soil and sediment concentrations, in-turn, are relatively low and would not be expected to cause groundwater concentrations to exceed the MCLs for the nuclides evaluated. The distribution coefficients derived for fill soil at HNP appear to be reasonably representative of most of the soil material on the peninsula. The following exceptions were identified for application of the distribution coefficients:

• The fine-textured bottom sediments of the discharge canal, which are expected to exhibit substantially higher distribution coefficient than the sandy fill material; and
• The finer-textured and higher organic-content wetland soil in Unit 9530-05, also expected to exhibit substantially higher distribution coefficient that the sandy fill material tested.

In both cases where the distribution coefficients may not be fully representative of the samples evaluated, use of the distribution coefficients established for this assessment is conservative and in no instance was the high Kd soil screening concentration exceeded Survey Unit 9106 - Discharge Canal Sediment Assessment Ten radionuclides were detected in sediment samples from the canal. The nudlides detected are described in detail in Appendix A, Table A-3 and A-4. Cobalt-60, cesium-137, and stontium-90 are widely distributed in the canal bottom. Cobalt-60 was detected in 71 samples, cesium-137 was detected in 64 samples and strontium-90 was detected in 43 samples. The soil screening concentrations derived from the distribution coefficient study were conservatively applied to the canal sediments. The maximum observed concentrations of cobalt-60, strontium-90, and cesium-137 exceeded the low Yd screening concentration, but not the high-Kd screening concentration. The Kds for nuclides of interest in the fine-grained canal bottom sediments are expected to be substantially higher than those of the sandy backfill soil samples. With the higher Kds associated with fine grained sediments, the in-situ canal sediments are not believed to be a current source of groundwater contamination to the peninsula. Historically-dredged discharge canal sediments mixed with sand could be a possible source for Sr-90 detections in groundwater samples on the peninsula, depending on the concentration and Kd of the final mixture. Survey Unit 9530-01 Soil Assessment Radionuclides detected in soil samples collected in Survey Unit 9330-01 are detailed in Appendix A, Table A-5. Four nuclides were detected in samples collected from Unit 9530-01; cesium-137 was detected in 26 samples, cesium-134 in 1 sample, carbon-14 in 1 sample and technetium-99 in one sample. The observed soil nuclide concentrations in this unit do not exceed the soil screening concentrations based on the lowest Kds of the nudlides for which the screening concentrations were established (i.e., Cs-137 and Cs-134 - assumed to behave like Cs-137). Estimated equilibrium groundwater concentrations of those nudlides calculated using the backfil Kd and Unit 1 soil samples are consistent with nuclide PAGE 17 OF 21 8 FEB 05-PESUA GN EVALUAT1ON-CWM

detections in groundwater. Soil in Unit 9530-01 is not expected to contribute to future elevation of radionuclide concentrations in groundwater. Survey Unit 9530-02 Soil Assessment Radionuclides detected in soil samples collected in Survey Unit 9530-02 are detailed in Appendix A, Table A-6. Only two'nuclides were detected in samples from this unit; cesium-137 in 16 samples and carbon-14 in one sample. The observed soil nuclide concentrations in this unit do not exceed the soil screening concentrations based on the lowest Kds of the nuclide for which the screening concentrations were established (ie., Cs-137). Estimated equilibrium groundwater concentrations of those nudlides calculated using the backfill Kd and Unit 2 soil samples are consistent with nuclide detections in groundwater. Soil in Unit 9530-02 is not expected to contribute to future elevation of radionuclide concentrations in groundwater. Survey Unit 9530-03 Soil Assessment Radionuclides detected in soil samples collected in Survey Unit 9530-03 are detailed in Appendix A, Table A-7. Five nuclides were detected in soil samples from this unit; cesium-137 in 16 samples, strontium-90 in 1 sample, manganese-54 in 1 sample, carbon-14 in 1 sample, and iron-55 in two samples. The observed soil nuclide concentrations in this unit do not exceed the soil screening concentrations based on the lowest Kds of the nuclides for which the screening concentrations were established (i.e., Cs-137, Sr-90, and Fe-55). Estimated equilibrium groundwater concentrations of those nuclides calculated using the backfill Kd and Unit 3 soil samples are consistent with nuclide detections in groundwater. Soil in Unit 9530-03 is not expected to contribute to future elevation of radionuclide concentrations in groundwater. Survey Unit 9530-04 Soil Assessment Radionuclides detected in soil samples collected in Survey Unit 9530-04 are detailed in Appendix A, Table A-8. Four nuclides were detected in soil samples from this unit; cesium-137 in 23 samples, plutonium-239 in 1 sample, strontium-90 in 1 sample, and carbon-14 in 1 sample. The observed soil nuclide concentrations in this unit do not exceed the soil screening concentrations based on the lowest Kds of the nuclides for which the screening concentrations were established (i.e., Cs-137 and Sr-90). Estimated equilibrium groundwater concentrations of those nuclides calculated using the backfill Kd and Unit 4 soil samples are consistent with nuclide detections in groundwater. Soil in Unit 9530-04 is not expected to contribute to future elevation of radionuclide concentrations in groundwater. Survey Unit 9530.05 Soil Assessment Radionuclides detected in soil samples collected in Survey Unit 9530-05 are detailed in Appendix A, Table A-9. Five nuclides were detected in soil samples from this unit; cesium-137 in 14 samples, cobalt-60 in 11 samples, strontium-90 in 3 samples, tedmetium-99 in 1 sample, and carbon-14 in I sample. The observed soil cobalt-60 concentrations in 7 samples from this unit exceed the soil screening concentration based on the lowest Kd of the nuclide, although the actual magnitude of exceedence is small. The observed soil strontium-90 concentration in 1 sample equaled, but did not exceed the soil screening concentration based on the lowest Kd of the nuclide. None of the observed soil nuclide concentrations in this unit exceed the soil screening concentration based on the highest Kds of nuclides for which the screening concentrations were established (Le., Cs-137, Sr-90, and Co-60). Unit 5 PAGE 18OF 21 8 FEB OCPENNSULA GN EVALUAT1ON-CWM

includes a relatively large area of wetland that exhibits substantial plant growth. This area is subject to inundation by water from the discharge canal during high tide. The soil in this unit is expected to contain a larger content of natural organic matter than the neighboring areas of the peninsula and may, therefore, be expected to exhibit substantially-higher distribution coefficients for nudlides of interest than the sandy fill soil used to develop the Kds. Estimated equilibrium groundwater concentrations of those nuclides calculated using the backfill K1 and Unit 5 soil samples are consistent with nuclide detections in groundwater. Soil in Unit 9530-05 is not expected to contribute to future elevation of radionuclide concentrations in groundwater. Survey Unit 9531-00 Soil Assessment Survey Unit 9531-00, which encompasses the southern-most portion of the lower peninsula was evaluated during final status survey and determined to be un-impacted by plant operations. No additional characterization (e.g., soil sampling and analysis) has been performed in this survey unit and no contamination sources have been identified. No potential contribution to observed groundwater contamination in the lower peninsula is attributed to Survey Unit 9531-00. 6 Conclusions and Recommendations The intermittent historical detection of Sr-90 in groundwater from well MW-117S and other locations in the lower peninsula area of HNP is consistent with low-level contamination resulting from either historical migration of water from the discharge canal into the aquifer underlying the peninsula, or leaching of very low levels of radionuclides from dredge spoils historically placed on the peninsula surface. Well MW-117S should be kept as part of the HNP groundwater monitoring system and sampled during regularly-scheduled sampling events. Groundwater contaminant concentrations in the lower peninsula are expected to decrease and detection of radionuclides in groundwater to become less frequent. Radionuclides detected in wells located in the upper peninsula (i.e., the "boneyard") area are consistent with identified sources in the boneyard (i.e., the sanitary sewage system/leach field) and with migration of contaminants from the central industrial area of the plant. Groundwater contaminant concentrations in the upper peninsula wells are expected to continue to vary as plant decommissioning activities continue in that area and as identified plant-related contaminant plumes continue to migrate in the direction of the upper peninsula. The upper peninsula groundwater should be addressed in concert with the remainder of the industrial area. PAGE 19 OF21 8FEBCIP-EiNSULA G EVALUATIONLCM

7 References Brookhaven National Laboratory, November 2004. Kd Values of Backfill Matenialfor Connecticut Yankee, Final Report CH2hl HILL, Inc., April 2004. Plhase 2 Hydrogeologic ClharacterizationWork Plan Task 1 Sumnnianj Report. Connecticut Yankee Atomic Power Company, Haddam Neck PIant. CYAPCO, October 2004. Seii-Aunial GroundwaterMIonitoring Report Mardc and June 2004 Quarterly Samnpling Events. Connecticut Yankee Atomic Power Company, Haddam Neck Plant. CYAPCO, 2005. Final Status Survey Historical Records Database, dredge spoil records. Leggette, Brashears & Graham, Inc., 1985, Conmpletion reportforthe htydrogeologicshudy of tie watersupply potential at the ConnecticutYankee Atonic PowerPlant,Haddani, Connecticut, Leggette, Brashears, and Graham, Inc., Consulting Ground-Water Geologists, Wilton, Connecticut. MAC-EC, June 2004. MAC-EC canal field investigation. United States Environmental Protection Agency, Office of Ground Water and Drinking Water (4606M), March 2002. IniplenientationGiddanceforRadionzuclides, EPA 816-F-00-002. www.epa.gov/safewater PAGE 20 CF 21 EVAATION.CWM BFED05-PENINSUA GW

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Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From tiNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT I 2-Sigma Actual Analysis Well ID NuclidelAnalyte (unit) l Net Concentration TPU MDC Date MW-1 Ag-1 08m(pCVL) 0.784 j 1.2 2.15 t 19-Jul-04 MW-1 Ag-108m(pCVL)_ -0.826 [ 2.72 4.51 18-Oct-04 MW-1 Am-241(pCUL) -1.81 2.35 4 19-Jul-04 MW-1 Am-241-gamma(pCi/L) -22.2 18.1 27.6 I 18-Oct-04 MW-1 Borcn(ug/L) 5.08 - 0.54 26-Jul-04 MW-1 Boron(ugIL) 5.2 0.54 22-Oct-04 MW-1 Co-60(pCVL) J 0.75 1.58 I 2.95 19-Jul-04 MW-1 Co-60(pCVL) . 0.174 2.9 5.58 18-Oct-04 MW-1 Cs-134(pCi/L) 1.02 1.47 2.73 19-Jul-04 MW-1 Cs-134(pCUL) -2.38 2.83 4.55 18-Oct-04 MW-1 Cs-137(pCVL) -0.248 1.38 2.41 19-Jul-04 MW-1 Cs-137(pCi/L) 1.01 2.7 5.15 18-Oct-04 MW-1 Eu-I 52(pCIIL) 1.5 3.57 6.33 19-Jul-04 MW-1 Eu-152(pCI/L) 3.48 8.39 15 18-Oct-04 MW-1 Eu-154(pCi/L) -1.42 4.1 7.13 19-Jul-04 MW-1 Eu-154(pCIIL) J -0.992 6.34 12.2 18-Oct-04 MW-1 Eu-155(pCl/L) 1,'Ttr, 94-' .; 3.94 6.94 19-Jul-04 MW-1 Eu-155(pCi/L) -4.5 9.71 17 18-Oct-04 MW-1 Gross Alpha(pCllL) 0.302 0.939 2 26-Jul-04 MW-1 Gross Alpha(pCYL) -0.254 0.552 1.35 16-Oct-04 MW-1 Gross Beta(pCIIL) 0.234 0.875 1.84 26-Jul-04 MW-1 Gross Beta(pCUL)  :,.r.VR1.33...';WY 1.16 2.24 16-Oct-04 MW-1 H-3(pCVL) ' 223\3/4 - 172 274 20-Jul-04 MW-1 H-3(pCUL) 51.9 183 305 7-Oct-04 MW-1 Mn-54(pCUL) 1.41 1.43 2.69 19-Jul-04 MW-1 Mn-54(pCI/L) -1.74 2.46 4.04 18-Oct-04 MW-1 Nb-94(pCVL) -0.174 1.29 2.26 19-Jul-04 MW-1 Nb-94(pCUL) -1.52 2.19 3.66 18-Oct-04 MW-1 Sr-90(pCVL) _.;:#-0.944e.-' 0.726 1 1.47 15-Jul-04 MW-110S AcTh-228(pCV/L) -7.9 9.4 21 25-Jun-03 MW-110S Ag-108m(pCi/L) 0.243 1.22 2.23 21 -Nov-02 MW-110S Ag-108m(pCI/L) -0.445 1.12 1.9 22-Jan-03 MW-110S Ag-108m(pCUL) 1.13 2.26 1 4.22 30-Apr-03 MW-110S Ag-1 08m(pCIIL) 1.1 2.4 4.3 25-Jun-03 MW-1IOS Ag-108m(pCUL) 0.646 1.47 2.85 22-Nov-03 MW-110S Ag-108m(pCUL) -0.689 2.56 4.55 21-Jan-04 MW-110S Ag-108m(pCI/L) 0.273 1.69 3.12 1-Apr-04 MW-110S Ag-108m(pCUL) -1.55 1.4 2.2 19i-u-04 MW-110S Ag-l1 Om(pCVL) 0 3.4 6.5 25-Jun-03 MW-110S Am-241 (gamma)(pCi/L 4.09 26 47 1-Feb-02 MW-11S Am-241 (gamma)(pCUL) -2.9 5.22 8.57 31-Jul-02 MW-110S Am-241 (gamma)(pCVL) -0.499 1.76 2.54 28-Aug-02 MW-110S Am-241 (gamma)(pCI/L) -2.99 3.81 6.32 21 -Nov-02 MW-110S Am-241 (gamma)(pCVL) -1.83 1.57 2.45 22-Jan-03 MW-110S Am-241 (gamma)(pCIL) -16 22.7 36.9 30-Apr-03 MW-1I1S Am-241 (gamma)(pCLL) 1.71 1 2.38 4.41 22-Nov-03 MW-110S Am-241 (gamma)(pCVL) 4.88 1 10.1 17.3 1-Apr-04 MW-110S Am-241 (gamma)(pCUL) 0.753 2.45 4.22 19-Jul-04 MW-110S Am-241(pCUL) 0.0 0673 0.169 31-Jul-02 I of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 12-Sigma I Actual I Analysis Well ID Nuclide/Analyte (unit) l Net Concentration j TPU MDC Date MW-110S Am-241(pCVL) I 0.0451 1 0.0906 0.122 25-Aug-02 MW-110S Am-241(pCVL) l 0.0481 1 0.0966 0.13 18-Dec-02 MW-110S Am-241(pCVL) 0.0768 0.109 0.104 30-Jan-03 MW-110S Am-241 (pCVL) 0 0.105 0.116 7-May-03 MW-110S Am-241 (pCUL) -0.0429 0.104 0.354 5-Apr-04 MW-110S Ba-140(pCiIL) -7 15.6 35 25-Jun-03 MW-110S Be-7(pCVL) 3 34 64 25-Jun-03 MW-110S Boron(ugIL) 238 - 0.54 15-Apr-04 MW-110S Boron(ug/L) 191 - 4.88 15-Apr-04 MW-110S Boron(ug/L) 291 l 0.54 26-Jul-04 MW-110S C-14(pCUL) 1.46 5.06 11 5-Aug-02 MW-110S C-14(pCUL) $.4.19 i ;:- 3.72 7.85 10-Aug-02 MW-110S C-14(pCVL) -3.5 3.8 8.57 8-Nov-02 MW-110S C-14(pCUL) 0.923 3.61 7.88 15-Jan-03 MW-110S Ce-141(pCVL) 3 9.4 16 25-Jun-03 MW-110S Ce-144(pCilL) 3.6 18.4 32 25-Jun-03 MW-110S Cm-242(pCl/L) 0 0.18 0.199 31-Jul-02 MW-110S Cm-242(pCIlL) -0.0116 0.0233 0.278 25-Aug-02 MW-110S Cm-242(pCi/L) -0.0139 0.0279 0.332 18-Dec-02 MW-110S Cm-242(pCVL) 0 0.114 0.126 30-Jan-03 MW-110S Cm-242(pCUL) 0 0.123 0.136 7-May-03 MW-110S Cm-243,244(pCUL) -0.0034 0.00682 0.171 31-Jul-02 MW-110S Cm-243,244(pCVL) 0 1 0.111 0.123 25-Aug-02 MW-110S Cm-243,244(pCUL) 0 0.119 0.131 18-Dec-02 MW-110S Cm-243,244(pCVL) 0 0.0945 0.105 30-Jan-03 MW-110S Cm-243,244(pCllL) 0.0431 0.0866 0.117 7-May-03 MW-110S Co-57(pCUL) -10 24 42 25-Jun-03 MW-110S Co-58(pCUL) 1.7 3 5.2 25-Jun-03 MW-110S Co-60(pCUL) -4.87 5.5 11 1-Feb-02 MW-110S Co-60(pCUL) 2.13 2.2 4.37 31-Jul-02 MW-110S Co-60(pCI/L) 0.398 1.43 2.83 28-Aug-02 MW-110S Co-60(pCitL) 1.09 2.05 3.98 21-Nov-02 MW-110S Co-60(pCIVL) -0.367 1.3 2.34 22-Jan-03 MW-110S Co-60(pCiUL) 0.565 2.49 5.07 30-Apr-03 MW-110S Co-60(pCIL) 0.8 2.2 3.9 25-Jun-03 MW-110S Co-60(pCUL) -0.958 1.87 3.25 22-Nov-03 MW-110S Co-60(pCUL) -1.52 3.51 6.43 21-Jan-04 MW-110S Co-60(pCUL) 0.291 2.02 3.86 1-Apr-04 MW-110S Co-60(pCUL) 0.194 1.86 3.42 19-Jul-04 MW-110S Cr-51 (pCUL) -13 50 93 25-Jun-03 MW-110S Cs-134(pCUL) -3.33 4.9 8 1-Feb-02 MW-l0S Cs-134(pCUL) -0.97 1.95 3.33 31-Jul-02 MW-110S Cs-134(pCiUL) 0.432 1.35 2.61 28-Aug-02 MW-110S Cs-134(pCVL) -0.929 1.86 3.14 21-Nov-02 MW-110S Cs-134(pCVL) 0.0694 1.44 2.64 22-Jan-03 MW-110S Cs-134(pCUL) -0.498 2.76 5.01 30-Apr-03 MW-110S Cs-134(pCUL) -1.7 3 6.2 25-Jun-03 MW-110S Cs-134(pCllL) I 1.1 2.16 4.44 22-Nov-03 MW-110S Cs-134(pCi/L) -0.477 4.22 7.79 21-Jan-04 2 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l 2-Sigma Actual I Analysis Well ID Nucllde/Analyte (unit) Net Concentration l TPU MDC l Date MW-110S Cs-134(pCIlL) 0.739 2.01 3.75 1 1-Apr-04 MW-110S Cs-134(pCIIL) -0.753 1.87 3.21 1 19-Jul-04 MW-110S Cs-137(pCilL) 0.738 5 9 1 1-Feb-02 MW-110S Cs-137(pCIIL) -0.325 1.75 3.05 31-Jul-02 MW-110S Cs-137(pCilL) 0.629 1.34 2.57 28-Aug-02 MW-110S Cs-137(pCUL) 0.353 1.45 2.72 21-Nov-02 MW-110S Cs-137(pCUL) -0.0573 1.27 2.31 22-Jan-03 MW-110S Cs-137(pCUL) 0.844 2.65 4.97 30-Apr-03 MW- 10S Cs-1 37(pCtlL) 1.2 2.6 4.6 25-Jun-03 MW-110S Cs-137(pCi/L) -0.31 1.87 3.45 22-Nov-03 MW-110S Cs-137(pCUL) -0.185 3.24 6.15 21-Jan-04 MW-110S Cs-137(pCUL) 0.128 1.88 3A1 1-Apr-04 MW-110S Cs-1 37(pCUL) 1.45 1.86 3.05 19-Jul-04 MW-110S Eu-152(pCUL) 1.73 12 22 1-Feb-02 MW-110S Eu-152(pCUL) -2.91 4.06 6.74 31-Jul-02 MW-110S Eu-152(pCUL) 2.46 3.05 5.83 28-Aug2 MW-110S Eu-152(pCUL) -1.14 3.65 6.24 21 -Nov-02 MW-110S Eu-152(pCVL) -0.969 3.26 5.64 22-Jan-03 MW-110S Eu-152(pCUL) 2.12 6.68 12.2 30-Apr-03 MW-110S Eu-1 52(pCVL) -2.8 6.6 12 25-Jun-03 MW-1i S Eu-152(pCUL) 1.59 5.07 9.46 22-Nov-03 MW-1ltS Eu-152(pCUL) 3.18 l 8.76 16.7 21-Jan-04 MW-D10S Eu-1 52(pCIIL) 4.28 I 5.5 9.96 1-Apr-04 MW-110S Eu-152(pCIlL) 0.288 3.89 6.77 19-Jul-04 MW-110S Eu-1 54(pCi/L) -3.29 17 30 1-Feb-02 MW-110S Eu-154(pCllL) -3.62 5.18 8.56 31-Jul-02 MW-110S Eu-154(pCI/L) -0.685 3.61 6.7 28-Aug-02 MW-110S Eu-154(pCIUL) -3.53 l 4.41 7.14 21-Nov-02 MW-110S Eu-154(pCUL) 1.6 1 3.83 7.73 22-Jan-03 MW-110S Eu-154(pCVL) 6.82 7.24 16.1 30-Apr-03 MW-110S Eu-154(pCVL) 5.9 8.6 14 25-Jun-03 MW-110S Eu-154(pCUL) *S;  ; - .. 4.61 12 22-Nov-03 MW-110S Eu-154(pCVL) 4.95 10.4 23.2 21-Jan-04 MW-110S Eu-1 54(pCUL) 0.463 4.23 8.39 1-Apr-04 MW-110S Eu-154(pCUL) 2.66 4.74 9.18 19-Jul-04 MW-110S Eu-155(pCilLj -11.4 16 26 1-Feb-02 MW-110S Eu-155(pCt/L) 0.537 3.74 6.49 31-Jul-02 MW-110S Eu-155(pCUL) -1.89 2.4 3.84 28-Aug-02 MW-110S Eu-155(pCIUL) l 0.519 3.16 5.48 21-Nov-02 MW-110S Eu-155(pCIlL) I 1.04 2.32 4.22 22-Jan-03 MW-110S Eu-155(pCIlL) 0.77 7.61 13.5 30-Apr-03 MW-110S Eu-155(pCIIL) 4.1 10.8 18 25-Jun-03 MW-110S Eu-155(pCUL) 2.61 I 3.16 6.17 22-Nov-03 MW-110S Eu-155(pCUL) -4.82 l 6.68 11.2 21-Jan-04 MW-110S Eu-155(pCVL) 5.24 6.81 12.5 1-Apr-04 MW-110S Eu-1 55(pCVL) -1.15 4.2 6.86 19-Jul-04 MW-110S Fe-55(pCVL) .; .05 ':f 2.44 6.32 25-Jul-02 MW-110S Fe-55(pCllL)  :..-:;10.6:-;;'.i. 3.58 11.7 30-Aug-02 MW-110S Fe-55(pCilL) -5.54 5.19 10.6 8-Dec-02 3 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l2-Slgmal Actual lAnalysis Well ID NuctidelAnalyte (unit) Net Concentration -gTPU AMDC Date MW-110S Fe-55(pCiL) -8.85 l 3.83 6.23 1-Feb-03 MW-110S Fe-59(pCVL) -6.1 9 19 25-Jun-03 MW-110S Gross Alpha(pCUL) 0.379 1.2 0.94 13-Feb-02 MW-110S Gross Alpha(pCVL) 0.402 0.51 0.965 16-Jul-02 MW-110S Gross Alpha(pCVL) 0.0576 0.359 0.952 21-Aug-02 MW-110S Gross Alpha(pC-UL) -0.0147 0.281 0.813 5-Dec-02 MW-110S Gross Alpha(pCUL) -0.0348 0.274 0.863 21-Jan-03 MW-110S Gross Alpha(pCi/L) 0.138 0.368 0.858 7-May-03 MW-110S Gross Alpha(pCUL) 0.91 1.56 l 2.7 25-Jun-03 MW-110S Gross Alpha(pCVL) -0.022 0.764 1.93 22-Nov-03 MW-110S Gross Apha(pCiVL) 0.0386 0.469 1.22 22-Jan-04 MW-110S Gross Alpha(pCVL) -0.164 0.562 1.33 13-Apr-04 MW-110S Gross Alpha(pCUL) -0.0535 0.988 2.44 22-Jul-04 MW-110S Gross Beta(pCI/L) 2.79 1.4 0.88 13-Feb-02 MW-110S Gross Beta(pCI/L) 4.07 1.66 2.81 16-Jul-02 MW-110S Gross Beta(pCl/L) 6.51 1.89 2.66 21-Aug-02 MW-110S Gross Beta(pCUL) 4.39 1.63 2.62 5-Dec-02 MW-110S Gross Beta(pCI/L) 4.28 1.61 2.59 20-Jan-03 MW-110S Gross Beta(pCI/L) 7.47 2.03 2.74 7-May-03 MW-110S Gross Beta(pCUL) 7.3 2.4 2.7 25-Jun-03 MW-110S Gross Beta(pCUL) l 3.99 1.61 2.73 22-Nov-03 MW-110S Gross Beta(pCUL) 4.7 1.63 2.58 20-Jan-04 MW-110S Gross Beta(pCUL)I 1.88 0.765 1.27 13-Apr-04 MW-1iOS Gross Beta(pCYL) l 4.35 i 1.33 2.05 22-Jul-04 MW-110S H-3(pCIIL) 3270 440 240 11-Feb-02 MW-110S H-3(pCI/L) 2980 366 268 27-Jul-02 MW-110S H-3(pCIIL) 1470 268 259 18-Aug-02 MW-110S H-3(pCVL) 2390 242 278 14-Nov-02 MW-110S H-3(pCUL) 2050 221 289 25-Jan-03 MW-110S H-3(pCUL) 1430 183 256 8-May-03 MW-110S H-3(pCVL) 1370 240 330 25-Jun-03 MW-110S H-3(pCUL) 1420 203 297 9-Nov-03 MW-110S l H-3(pCi/L) 1290 178 255 14-Jan-04 MW-110S H-3(pCUL) 2050 287 282 3-Apr-04 MW-110S H-3(pCVL) 1010 220 310 19-iul-04 MW- 10S 1-131 (pCIIL) -25 52 99 25-Jun-03 MW-110S K-40(pCl/L) 10 32 58 25-Jun-03 MW-110S La-140(pCVL) -8.1 17.8 41 25-Jun-03 MW-110S Mn-54(pCllL) 0.0197 4.7 8.6 1-Feb-02 MW-110S Mn-54(pCI/L) -2.52 2.36 3.73 31-Jul-02 MW-I i OS Mn-54(pCIIL) 0.0538 1.33 2.46 28-Aug-02 MW-110S Mn-54(pCIIL) -0.595 1.61 2.76 21-Nov-02 MW-110S Mn-54(pCUL) 0.0934 1.24 2.3 22-Jan-03 MW-11OS Mn-54(pCUL) -2.24 2.99 4.92 30-Apr-03 MW-110S Mn-54(pCI/L) 0.8 I 2.8 5.1 25-Jun-03 MW-1 lOS Mn-54(pCVL) 0.65 2.16 4.26 22-Nov-03 MW-1IDS Mn-54(pCVL) -2.59 3.05 4.91 21 -Jan-04 MW-110S Mn-54(pCVL) 0.726 2.11 3.87 1-Apr-04 MW-110S Mn-54(pCUL) 0.368 1.7 1 3.06 19-Jul-04 4 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT I 2-Sigma Actual Analysis Well ID Nuclide/Analyte (unit) l Net Concentration TPU MDC Date MW-110S Nb-94(pCIUL) 3.08 I 4.1 8.4 1-Feb-02 MW-10S Nb-94(pCVL) -0.739 1.81 3.08 I 31-Jul-02 MW-I 10S Nb-94(pCI/L) 0.169 1.23 2.31 28-Aug-02 MW-110S Nb-94(pCUL) 0.76 1.35 2.6B 21-Nov-02 MW-110S Nb-94(pCUL) -0.0717 1.13 2.08 22-Jan-03 MW-110S Nb-94(pCUL) -1.46 2.47 4.19 30-Apr-03 MW-110S Nb-94(pCUL) -2.4 2.4 5.3 25-Jun-03 MW-110S Nb-94(pCi/L) -1.28 1.72 2.76 22-Nov-03 MW-110S Nb-94(pCI/L) -1.54 3.58 6.39 21-Jan-04 MW-t10S Nb-94(pCIIL) 0.432 1.64 3.04 1 -Apr-04 MW-110S Nb-94(pCllL) 0.0195 1.7 2.68 19-Jul-04 MW-110S Nb-95(pCI/L) I 2.3 4.2 7.4 25-Jun-03 MW-110S Ni-63(pCiIL) L , .. . 2.75 3.96 25-Jul-02 MW-1I OS Ni-63(pCi/L) 0.0155 1.9 3.07 l 30-Aug-02 MW-110S NI-63(pCVL) 3.12 4.12 5.32 8-Dec-02 MW-110S NI-63(pCUL) 1.16 2.71 3.79 31-Jan-03 MW-11 0S Pu-238(pCIlL) 0 0.108 0.12 8-Aug-02 MW-110S Pu-238(pCllL) 0.0328 0.0837 0.196 23-Aug-02 MW-11 Os Pu-238(pCUL) 0 0.121 0.134 4-Dec-02 MW-i 10S Pu-238(pCUL) 0 0.117 0.129 23-Jan-03 MW- 10S Pu-238(pCVL) 0 0.218 0.242 1-May-03 MW-11OS Pu-239,240(pCL) 0.044 0.0883 0.119 8-Aug-02 MW-110S Pu-239,240(pCVL) 0.0654 0.118 0.231 23-Aug-02 MW-110S Pu-239,240(pCilL) -0.00989 0.0198 0.237 4-Dec-02 MW-110S Pu-239,240(pCUL) -0.00954 0.0192 0.228 23-Jan-03 MW- 10S Pu-239,240(pCUL) 0 0.218 0.241 1-May-03 MW-110S Pu-241 (pCl/L) 6.91 3.46 6.84 14-Aug-02 MW-llS Pu-241 (pCi/L) -10.3 3.23 7.57 1-Sep-02 MW-110S Pu-241 (pCUL) -4.I 2: 3.94 8.04 27-Dec-02 MW-110S Pu-241(pCUL) 13.2 4.58 8.16 31-Jan-03 MW-110S Pu-241 (pCVL) 2.63 8.3 15.1 12-May-03 MW-110S Ru-103(pCUL) -0.1 5.2 9.4 25-Jun-03 MW-110S Ru-106(pCVlL) -4 24 46 25-Jun-03 MW-110S Sb-124(pCUL) -1.2 9.6 20 25-Jun-03 MW-110S Sb-125(pCVL) 1.39 12 23 1-Feb-02 MW-1IOS Sb-125(pCUL) -1.1 6.4 12 25-Jun-03 MW-110S Se-75(pCUL) 2.4 3.4 5.6 25-Jun-03 MW-110S Sr-89(pCIL) -0.235 0.34 0.6 18-Feb-02 MW-110S Sr-89(pCIIL) -2 17.2 39 25-Jun-03 MW-110S Sr-90(pCIVL) 0.0494 0.23 0.39 18-Feb-02 MW-110S Sr-90(pCI/L) . L,

                                          ^,0.339j,     :;';     0.333    0.603    4-Aug-02 MW-110S             Sr-90(pCI1L)      1         0.169              0.266   0.545 25-Aug-02 MW-llOS             Sr-90(pCUL)       1 -0.0227                   0.295    0.683 ! 8-Dec-02 MW-110S             Sr-90(pCVL)       I         0.238             0.273    0.528   24-Jan-03 MW-11S              Sr-90(pCUL)         - .e 0:322                 0.319   0.597 j 7-May-03 MW-110S             Sr-90(pCIIL)      J           0.1              0.96      1.6   25-Jun-03 MW-110S             Sr-90(pCIIL)      I          0.16              0.204 1 0.423 23-Nov-03 MW-110S             Sr-90(pCIUL)      j       p0.439.       .'     0.36 j 0.687    18-Jan-04 MW-110S             Sr-90(pCIUL)      1        -0.753             0.648     1.7     6-Apr-04 5 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l 2-Sigma I Actual I Analysis Well ID Nuclide/Analyte (unit) Net Concentration TPU MDC I Date MW-110S Sr-90(pCUL) ';-O.689  ;' 0.637 1 j 13-Jul-04 MW-110S Tc-99(pCVL) t-'--6.1'8.44 -;- 7.78 I 11.3 l 10-Aug-02 MW-110S Tc-99(pCUL)  ; ..7.58 '. -; 7.53 11.2 24-Aug-02 MW-110S Tc-99(pCUL) 2.61 7.11 10.8 19-Nov-02 MW-110S Tc-99(pCUL) 6.4 8.31 11.5 24-Jan-03 MW-110S Total U(pCI/L) 0.0122 0.00135 0.00978 30-Jan-04 MW-110S Zn-65(pCVL) -1.1 7.2 14 25-Jun-03 MW-110S Zr-95(pCVL) -2.5 5.8 12 25-Jun-03 MW-1IOS Ag-108m(pCVL) 3.33 3.71 5.29 20 0ct-04 MW-1l0S Am-241-gamma(pCVL) -3.88 16.6 28.8 20-Oct-04 MW-110S Blcarb. Alkalinity(ug/L) 16.2 - 1.45 13-Oct-04 MW-110S Boron(ugIL) 284 - 0.54 29-Oct-04 MW-110S Ca cation(ugIL) 34300 - 5.54 29-Oct-04 MW-110S Carb. Alkallnity(ugIL) 2 - 1.45 13-Oct-04 MW-110S Cl lon(uglL) 63.8 - 0.322 25-Oct-04 MW-110S Co-60(pCUL) -3.47 3.02 1 4.5 20-Oct-04 MW-110S Cs-134(pCI/L) 0.351 3.42 5.67 20-Oct-04 MW-110S Cs-137(pCUL) -0.901 2.77 4.98 20-Oct-04 MW-110S Eu-1 52(pCIIL) -0.0135 7.57 13.6 20-Oct-04 MW-1 10S Eu-154(pCVL) -4.01 9.26 13.7 l 20-Oct-04 MW-110S Eu-1 55(pCUL) -3.75 11.5 19.4 20-Oct-04 MW-110S Gross Alpha(pCIlL) -0.716 1 0.632 1.78 19-Oct-04 MW-110S Gross Beta(pCUL) 4.46 1.54 2.75 19-Oct-04 MW-I 10S H-3(pCVL) 1670 198 254 8-Oct-04 MW-110S K catlon(uglL) 4980 - 16.5 29-Oct-04 MW-110S Mg cation (ugIL) 5130 - 5.18 29-Oct-04 MW-110S Mn-54(pCVL) -1.79 2.96 4.99 20-Oct-04 MW-110S Na cation(ug/L) 19400 ] 14.4 29-Oct-04 MW-110S Nb-94(pCUL) 1.55 2.29 4.67 20-Oct-04 MW-110S Sr-90(pCIIL) 0.358 0.434 0.937 18-Oct-04 MW-110S Sulfate anlon(uglL) 23.8 - 0.193 1 22-Oct-04 MW-110S Total U(pCi/L) 00 i 0.2 i 13-Oct-04 MW-111S AcTh-22_(pCVL) 0 13.6 27 23-Jun-0 MW-111S Ag-108m(pCIIL) 0.00724 1.56 2.69 7-Nov-02 MW-111S Ag-108m(pCVL) -0.146 1.1 1.96 23-Jan-03 MW-111S Ag-108m(pCUL) 0.653 1.36 2.69 2-May-03 MW-111S Ag-108m(pCIVL) -0.3 i 2.6 5.3 23-Jun-03 MW-111S Ag-108m(pCiIL) -0.994 2.08 3.53 24-Nov-03 MW-illS Ag-108m(pCIIL) -3.31 I 3.86 6.23 28-Jan-04 MW-111S Ag-1 08m(pCiL) l ' 84:.':,: l 1.67 j 3.3 1-Apr-04 MW-111S Ap-108m(pCVL) 0.104 1.3 l 2.3 19-Jul-04 MW-1IlS Ag-1IOm(pCVL) j -0.5 5.6 1 1 23-Jun-03 MW-111S Am-241 (gamma)(pCUL)l 6.85 12 23 30-Jan-02 MW-111S Am-241 (gamma)(pCUL) -4.53 3.51 5.55 31-Jul-02 MW-i11S Am-241 (gamma)(pClIL) 1.57 1 3.71 6.63 29-Aug-02 MW-1IlS Am-241 (gamma)(pCUL) -9.59 l 15.7 26.2 7-Nov-02 MW-111S Am-241 (gamma)(pCUL) -1.03 3.42 5.89 23-Jan-03 MW-1IlS Am-241 (gamma)(pCIIL) .:.-b:2.92k'.:;:* 2.41 423 2-May-03 MW-111S Am-241 (gamma)(pCIL)- -0.306 j 10.3 18.1 24-Nov-03 6 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 12-Sigma Actual 1 Analysis Well ID Nuclide/Analyte (unit) Net Concentration TPU l MDC l Date MW-111S Am-241 (gamma)(pCIIL)I 2.12 11.4 19 i 1-Apr-04 MW-111S Am-241 (gamma)(pCU/L) -5.14 9.11 13.1 19-Jul-04 MW-I1S Am-241(pCVL) 0 0.153 0.169 31-Jul-02 MW-1IlS Am-241(pCUL) -0.00353 0.00709 0.178 26-Aug-02 MW-11l1 S Am-241 (pCUL) 0.0784 l 0.125 0.209 30-Jan-03 MW-11l1 S Am-241 (pCUL) I -0.014 0.0724 0.264 5-Apr-04 MW-1l1 S Ba-140(pCilL) 10 l 32 61 _ 23-Jun-03 MW-1l1 S Be-7(pCI/L) l 39 50 83 23-Jun-03 MW-illS Boron(ugIL) 55.5 - 1 0.54 j 26-Jul-04 MW-111S C-14(pCVL) 0.369 3.77 l 8.24 5-Aug-02 MW-I1S C-14(pCUIL) 2.75 3.67 7.85 I 10-Aug-02 MW-111S C-14(pCUL) 2.59 3.67 7.88 16-Jan-03 MW-111S Ce-141(pCUL) 0.3 11.2 20 23-Jun-03 MW-111S Ce-144(pCVL) -8 22 40 23-Jun-03 MW-1ilS Cm-242(pCVL) -0.0216 0.0433 0.517 31-Jul-02 MW-111S Cm-242(pCUL) -0.00916 0.0131 0.262 26-Aug-02 MW-ills Cm-242(pCUL) -0.0106 0.0212 0.253 30-Jan-03 MW-IllS Cm-243,244(pCi/L) -0.0127 0.0254 0.303 31 -Jul-02 MW-111S Cm-243,244(pCilL) -0.00355 0.00714 0.179 26-Aug-02 MW-111S Cm-243,244(pCUL) -0.0175 0.0249 0.247 30-Jan-03 MW-ills Co-57(pCU/L) -5 24 43 23-Jun-03 MW-1IlS Co-58(pCUL) 1.3 5.2 9.8 23-Jun-03 MW-1IlS Co-60(pCUL) 3.78 9.1 20 30-Jan-02 MW-111S Co-60(pCVL)  :- 3 1.5 3.36 31-Jul-02 MW-Ills Co-60(pCUL) -0.44 1.69 3.03 29-Aug-02 MW-111S Co-60(pCUL) 0.0892 1.82 l 3.37 7-Nov-02 MW-Ills Co-60(pCUL) -0.956 1.8 3.04 23-Jan-03 MW-111S Co-60(pCUL) -1.2 1.96 3.29 2-May-03 MW-1IlS Co-60(pCi/L) 0.3 4.2 1 8.5 23-Jun-03 MW-111S Co-60(pCI/L) -0.211 2.88 5.51 24-Nov-03 MW-11 S Co-60(pCi/L) 2.1 4.71 9.83 28-Jan-04 MW-111S Co-60(pCI/L) 0.367 2.24 3.78 1-Apr-04 MW-1IlS Co-60(pCi/L) 0.0721 1.44 2.6 19-Jul-04 MW-111S MW-111S MW-111S Cr-51 (pCilL) Cs-134(pCUL) Cs-134(pCilL) 17 1.68

                                             -0.00376 j

1 68 6.7 1.45 120 13 2.72 23-Jun-03 30-Jan-02 31-Jul-02 MW-1IlS Cs-1 34(pCi/L) -0.385 1.67 2.94 29-Aug-02 MW-111S Cs-134(pCl/L) 0.793 1 2.07 3.81 7-Nov-02 MW-illS Cs-1 34(pCi/L) 0.285 1.42 2.74 23-Jan-03 MW-111S Cs-134(pCI/L) -0.283 2.11 3.91 2-May-03 MW-ills Cs-134(pCUL) 0.6 3.8 7.5 23-Jun-03 MW-Ills Cs-134(pCVL) 1.98 2.46 5.23 24-Nov-03 MW-111S Cs-134(pCllL) -1.37 5.14 9.11 28-Jan-04 MW-111S Cs-1 34(pCUL) 1 t.3.33 2.4 4 1-Apr-04 MW-111S Cs-134(pCilL) 0.418 1.47 2.6 19-Jul-04 MW-111S Cs-137(pCUL) -5.09 7.6 13 30-Jan-02 MW-1ilS Cs-I 37(pCiL) -0.566 1.41 2.42 31-Jul-02 MW-111S Cs-1 37(pCilL) -0.0175 1.55 2.8 29-Aug-02 MW-111S Cs-i 37(pCllL) 1.24 I 2 3.69 7-Nov-02 7 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT I l2-Sigmal Actual j Analysis Well ID Nuclide/Analyte (unit) Net Concentration J TPU MDC Date MW-111S Cs-1 37(pCUL) -0.893 1 1.59 2.69 23-Jan-03 MW-IllS Cs-1 37(pCVL) -0,00904 l 2.04 3.82 2-May-03 MW-11lS Cs-137(pCI/L) -3.5 3.6 8.5 23-Jun-03 MW-11 S Cs-1 37(pCVL) -0.852 2.58 4.5 24-Nov-03 MW-111S Cs-I 37(pCVL) -4 I 4.39 7.09 I 28-Jan-04 MW-1IlS Cs-137(pCI/L) ' -2.13 2.27 3.06 1-Apr-04 MW-111S Cs-1 37(pCUL) 0.663 j1.33 2.4 19-Jul-04 MW-111S Eu-152(pCVL) -7.1 20 35 30-Jan-02 MW-illS Eu-152(pCUL) 0.284 j 3.49 6.16 31-Jul-02 MW-111S Eu-152(pCIlL) 1.12 3.99 7.1 29-Aug-02 MW-illS Eu-152(pCl)L) -0.578 4.91 8.41 7-Nov-02 MW-il 1S Eu-1 52(pCUL) 0.356 3.67 6.47 23-Jan-03 MW-111S Eu-I52(pCUL) 1.36 4.51 8.53 2-May-03 MW- 11 S Eu-152(pCIIL) -0.7 8 14 23-Jun-03 MW-111 S Eu-1 52(pCI/L) -5.39 5.79 9.4 24-Nov-03 MW-111 S Eu-152(pCI/L) -2.78 11.8 20.2 28-Jan-04 MW-IlS Eu-152(pCVL) -0.273 5.42 9.21 1-Apr-04 MW-111 S Eu-152(pCUL) -1.01 14.03 6.58 19-Jul-04 MW-111S Eu-154(pCUL) -22.6 24 37 30-Jan-02 MW-111S Eu-1 54(pCL) -0.871 4.57 8.26 31 -Jul-02 MW-111S Eu-154(pCUL) 2.02 3.85 l 8.05 29-Aug-02 MW-1S Eu-154(pCVL) 0.167 5.1 1 9.41 7-Nov-02 MW-111S Eu-154(pCVL) -2.77 4.48 r 7.48 23-Jan-03 MW-111S Eu-1 54(pCl/L) 2.11 4.97 J 11.1 2-May-03 MW-Il1S Eu-1 54(pCIlL) 0.9 11.4 23 23-Jun-03 MW-111S Eu-154(pCVL) 2.83 8.04 16.4 24-Nov-03 MW-111S Eu-154(pCVL) 4.94 14.6 29 28-Jan-04 MW-IllS Eu-154(pCVL) 3.44 5.58 11.3 1-Apr-04 MW-111S Eu-154(pCUL) -1.74 4.11 6.99 19-Jul-04 MW-111S Eu-155(pCIIL) 15.3 1 19 35 30-Jan-02 MW-1IlS Eu-I 55(pCUL) 0.422 l 2.76 4.83 31-Jul-02 MW-111S Eu-1 55(pCVL) . >4 2.84 5.32 29-Aug-02 MW-111S Eu-155(pCi/L) -1.35 5.27 8.9 7-Nov-02 MW-111S Eu-155(pCi/L) -1.38 3.11 5.13 23-Jan-03 MW-ills Eu-155(pCiIL) -2.12 3.56 6.06 2-May-03 MW-illS Eu-I 55(pCVL) 1.8 11.6 20 l 23-Jun-03 MW-111S Eu-155(pCVL) 2.65 5.33 10 24-Nov-03 MW-111S Eu-I 55(pCI/L) -0.372 10.2 17.9 1 28-Jan-04 MW-illS Eu-155(pCIIL) 4.25 7.07 12.8 l 1-Apr-04 MW-111 S Eu-1 55(pCVL) -0.2 4.6 8.03 l 19-Jul-04 MW-1ilS Fe-55(pCUL) 1 5.6I  : 2.6 6.49 25-Jul-02 MW-111S Fe-55(pC/L) ' 4:48 2.44 8.73 30-Aug-02 MW-111S Fe-55(pCI/L) -11.5 3.44 5.4 1-Feb-03 MW-111S Fe-59(pCVL) -7 13.2 29 23-Jun-03 MW-111S Gross Alpha(pCUL) 0.68 0.85 0.56 13-Feb-02 MW-111S Gross Alpha(pCUL) 1 0.592 0.673 1 16-Jul-02 MW-111S Gross Alpha(pCI/L) 0.345 0.391 0.696 21-Aug-02 MW-111S Gross Alpha(pCI/L) >' r  :' ; :-05410.521 0.892 6-Nov-02 MW-111S Gross Alpha(pCiUL) 0.355 l 0.391 0.671 l 21-Jan-03 8 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 2-Sigma Actual l Analysis Well ID Nuclide/Analyte (unit) Net Concentration TPU MDC l Date MW-111S Gross Alpha(pCI/L)  :.-0.548 0.469 0.701 i 2-May-03 MW-1IlS Gross Alpha(pC/L) 1.03 1.38 I 2.2 23-Jun-03 MW-1lS Gross Alpha(pCUL) 0.30B 0.396 l 0.714 23-Nov-03l MW-111S Gross Alpha(pCVL) 0.382 1 0.408 I 0.657 29-Jan-04 MW-111S Gross Alpha(pCIIL) 0.731 I 0.509 0.678 22-Apr-04 MW-111S Gross Alpha(pCIIL) -0.239 1.03 2.49 22-Jul-04 MW-111S Gross Beta(pCI/L) 4.23 1.6 0.98 13-Feb-02 MW-111S Gross Beta(pCUL) 5.31 1.66 2.42 16-Jul-02 MW-111S Gross Beta(pCIVL) 2.76 1.53 2.86 21-Aug-02 MW-111S Gross Beta(pCUL) 7.39 1.96 2.56 6-Nov-02 MW-111S Gross Beta(pCVL) 5.01 1.65 2.49 20-Jan-03 MW-111S Gross Beta(pCUL) 3.24 1.51 2.66 2-May-03 MW-1IlS Gross Beta(pCUL) 5.1 2.2 2.8 J 23-Jun-03 MW-111S Gross Beta(pCVL) 4.12 1.58 2.62 22-Nov-03 MW-111S Gross Beta(pCUL) 5.52 1.84 2.62 27-Jan-04 MW-1IlS Gross Beta(pCl/L) 4.95 l 1.41 2.37 22-Apr-04 MW-111S Gross Beta(pCIIL) s . 1.18 2.2 22-ul-04 MW-111S H-3(pCUL) -46.6 l 120 210 7-Feb-02 MW-IlS H-3(pCUL) 129 174 273 27-Jul-02 MW-111S H-3(pCUL) 165 169 259 18-Aug-02 MW-111S H-3(pCUL) l' 'r-; :222 129 274 21-Nov-02 MW-II1S H-3(pCUL) 120 128 292 25-Jan-03 MW-IIS H-3(pCUL) -0.903 107 253 2-May-03 MW- 11S H-3(pCVL) -100 240 350 23-Jun-03 MW-IIIS H-3(pCl/L) 2 299, ,W-: 147 306 9-Nov-03 MW-111S H-3(pCVL) -3.37 119 278 22-Jan-04 MW-111S H-3(pCIIL) 63.2 165 269 5-Apr-04 MW-1 1 S H-3(pCi/L) 233 'z 2 180 288 20-Jul-04 MW-1I1S 1-131(pCUL) 8 84 160 23-Jun-03 MW-1IlS K-40(pCVL) 7 54 100 23-Jun-03 MW-111S La-140(pCUL) 12 38 70 23-Jun-03 MW-111S Mn-54(pCUL) -3.24 8.7 156 30-Jan-02 MW-IIS Mn-54(pCUL) 1.64 1.84 3.71 31-Jul-02 MW-1IlS Mn-54(pCUL) -1.41 1.66 2.72 29-Aug-02 MW-IIS Mn-54(pCUL) 0.245 1.86 3.35 7-Nov-02 MW-1IlS Mn-54(pCUL) 0.547 1.59 3.02 23-Jan-03 MW-1ilS Mn-54(pCUL) 0.202 2.28 4.3 2-May-03 MW-111S Mn-54(pCUL) l 0.6 3.6 7 23-Jun-03 MW-111S Mn-54(pCUL) -1.31 2.61 4.5 24-Nov-03 MW-111S Mn-54(pCUL) -3.6 5.02 8.12 28-Jan-04 MW-111S Mn-54(pCUL) 0.442 1.82 3.35 1-Apr-04 MW-1i S Mn-54(pCVL) 0 1.85 2.29 19-Jul-04 MW-111S Nb-94(pCill) 3.08 18 35 30-Jan-02 MW-111S Nb-94(pCUL) 0.0993 1.39 2.57 31-Jul-02 MW-111S Nb-94(pClIL) -1.21 1.28 2.05 29-Aug-02 MW-111S Nb-94(pCUL) -0.812 1 1.56 2.67 7-Nov-02 MW-111S Nb-94(pCUL) -0.612 l 1.34 2.33 23-Jan-03 MW-111S Nb-94(pCVIL) -0.0828 l 1.62 3.11 2-May-03 MW-111 S Nb-94(pCUL) 0 l 4.2 8.1 23-Jun-03 9 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l2-Sigma lActual lAnalysis Well ID Nuclide/Analyte (unit) Net Concentration TPU MDC Date MW-111S Nb-94(pCV/L) -0.638 2.24 4.03 1 24-Nov-03 MW-1IlS Nb-94(pCUL) -0.151 4.84 8.92 28-Jan-04 MW-111S Nb-94(pCVL) 1.2 1.57 3.25 1-Apr-04 MW-111S Nb-94(pCUL) -0.669 1.33 2.2 l 19-Jul-04 MW-111S Nb-95(pCUL) -3.6 9.2 19 I 23-Jun-03 MW-I11S NI-63(pCIIL) 1.21 2.75 4.15 l 25-Jul-02 MW-111S Ni-63(pCi/L) 4.14 1 2.06 2.95. 30-Aug-02 MW-111S Ni-63(pCIIL) 0.917 l 2.61 3.68 J 1-Feb-03 MW-111S Pu-238(pCUL) -0.00828 l 0.0166 0.198 l 8-Aug-02 MW-I1S Pu-238(pClVL) 0 1 0.08 0.0885 26-Aug-02 MW-11 S Pu-238(pCUL) 0 l 0.0897 0.0992 24-Jan-03 MW-11 S Pu-239,240(pCVL) 0.0412 0.0827 0.112 8-Aug-02 MW-111S Pu-239,240(pCVL) 0 0.0799 0.0884 26-Aug-02 MW-11lS Pu-239,240(pCi/L) 0.00732 0.0147 0.175 24-Jan-03 MW-111S Pu-241 (pCilL) - 3.21 6.41 16-Aug-02 MW-11 S Pu-241 (pCI/L) -11.8 3.58 i 8.24 1-Sep-02 MW-111S Pu-24l (pCVL) 6.12 l 3.53 6.47 31-Jan-03 MW-111S Ru-103(pCUL) 3.2 7.2 13 23-Jun-03 MW-111S Ru-106(pCi/L) 15 28 50 23-Jun-03 MW-11lS Sb-124(pCUL) -14.9 17.2 41 23-Jun-03 MW-111S Sb-125(pCUL) 20.3 .. . . 19 40 30-Jan-02 MW-11S Sb-125(pCUL) 7.3 9.6 16 23-Jun-03 MW-111S Se-75(pCI/L) 3 5.8 10 23-Jun-03 MW-111S Sr-89(pCUL) -0.467 0.54 0.91 13-Mar-02 MW-1ilS Sr-90(pCUL) 0.209 0.29 0.37 13-Mar-02 MW-111S Sr-90(pCi/L) 0.321 0.336 0.629 4-Aug-02 MW-111S Sr-90(pCUL) 0.258 0.362 0.722 25-Aug-02 MW-11lS Sr-90(pCllL) 0.0B39 0.245 0.527 24-Jan-03 MW-111S Sr-90(pCUL)  ; 0:346 74-i 0.212 0.388 31-Jan-04 MW-111S Sr-90(pCUL) 0.0142 0.307 0.788 6-Apr-04 MW-111S Sr-90(pCVL) -0.0552 0.485 1.11 13-Jul-04 MW-111S Tc-99(pCl/L) . -". 0.1 11.3 10-Aug-02 MW-111S Tc-99(pCi/L) 4.54 7.5 11.3 10-Aua-02 MW-111S Tc-99(pCVL) 5.85 7.48 11.3 24-Aug-02 MW-1IlS Tc-99(pCUL) 2.93 8.14 11.6 24-Jan-03 MW-111S Total U(pCVL) 0.0397 0.00408 0.00978 2-Feb-04 MW-111S Zn-65(pCVL) -7.4 11 24 1 23-Jun-03 MW-111S Zr-95(pCI/L) -3 10.6 21 l 23-Jun-03 MW-112S AcTh-228(pCIUL) -5.7 13.4 29 23-Jun-03 MW-112S Ag-108m(pCVL) 0.739 1 1.35 2.48 7-Nov-02 MW-112S Ay-108m(pCVL) -0.0695 l 1.05 1.85 23-Jan-03 MW-112S Ag-108m(pCV/L) 0.0986 l 2.23 3.99 8-May-03 MW-112S Ag- 08m(pCVL) I -0.9 1 3.4 6.5 23-Jun-03 MW-112S Ag-108m(pCUL) T 0.212 1.7 l 3.1 24-Nov-03 MW-112S Ag-108m(pCUL) 1 0.678 1 3.85 7.09 21-Jan-04 MW-112S Ag-108m(pCl/L) 0.403 l 1.67 3.08 1-Apr-04 MW-112S Ag-108m(pCl/L) J 0.723 1 1.7 3.19 20-Jul-04 MW-112S Ag-108m(pCUL) l -0.747 l 1.8 3.03 19-Oct-04 MW-112S Ag-110m(pCUL) -2.8 5.6 12 23-Jun-03 10 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l2-Sigmal Actual lAnalysis Well ID Nuclide/Analyte (unit) I Net Concentration TPU MDC Date MW-112S Am-241 (gamma)(pCilL) 24.5 1 26 50 1-Feb-02 MW-112S Am-241 (gamma)(pCVlL) -1.25 2.61 3.64 29-Jul-02 MW-112S Am-241 (gamma)(pCUL) -0.117 1.59 2.52 29-Aug-02 MW-112S Am-241 (gamma)(pCilL)j 1.01 7.26 12.6 7-Nov-02 MW-112S Am-241 (gamma)(pCi/L) i -0.722 1.82 2.69 23-Jan-03 MW-112S Am-241 (gamma)(pCI/L)l -1.56 I 2.99 4.55 8-May-03 MW-112S Am-241 (gamma)(pCUL) 3.97 1 4.52 8.65 24-Nov-03 MW-112S Am-241 (gamma)(pCllL) 0.342 l 11.1 _ 19.7 j 1-Apr-04 MW-112S Am-241 (gamma)(pCUL) -18.8 l 18.2 27.3 20-Jul-04 MW-112S Am-241(pClL) 0 l 0.0677 0.0936 5-Apr-04 MW-112S Arn-241-garmma(pCiIL) -6.04 15.7 J 18.6 19-Oct-04 MW-112S Ba-140(pCUL) 0 32 1 66 23-Jun-03 MW-112S Be-7(pCUL) 30 46 79 j 23-Jun-03 MW-1i2S Boron(uglL) 47.8 - 0.54 26-Jul-04 MW-112S Boron(ug/L) 77.1 - 0.54 l 29-Oct-04 MW-112S Ce-141(pCIIL) 3.5 12 21 l 23-Jun-03 MW-112S Ce-144(pCIIL) I 26 47 23-Jun-03 MW-112S Co-57(pCIIL) -14 28 53 l 23-Jun-03 MW-112S Co-58(pCIlL) 1.2 4.8 9.1 23-Jun-03 MW-112S Co-60 (pCl/L) 0.929 2.21 4.29 19-Oct-04 MW-112S Co-60(pCIlL) -4.83 7.9 13 1-Feb-02 MW-112S Co-60(pCi/L) 1.06 1.6 3.93 129-Jul-02 MW-112S Co-60(pCilL) 0.672 1.48 2.99 29-Aug-02 MW-112S Co-60(pCilL) 0.668 1.82 3.59 7-Nov-02 MW-112S Co-60(pCilL) 0.43 1.1 2.32 23-Jan-03 MW-112S Co-60(pCVL) 0.283 2.67 5.27 B-May-03 MW-1 12S Co-60(pCiVL) 1 4.4 8.4 23-Jun-03 MW-112S Co-60(pCVL) 0.855 2.41 5.03 24-Nov-03 MW-112S Co-60(pCUL) 1.56 5.29 10.9 21 -Jan-04 MW-112S Co-60(pCiIL) -0.535 2.36 4.17 1-Apr-04 MW-112S Co-60(pCIL) -0.456 1.87 3.39 20-Jul-04 MW-112S Cr-51 (pCi/L) -26 74 140 23-Jun-03 MW-112S Cs-134(pCi/L) -6.18 8.8 12 1-Feb-02 MW-112S Cs-134(pCI/L) -0.135 1.45 2.64 29-Aug-02 MW-112S Cs-134(pCi/L) 0.0704 1.77 3.24 7-Nov-02 MW-112S Cs-1 34(pCI/L) 0.43 1.41 2.69 23-Jan-03 MW-112S Cs-134(pCIIL) 0.539 2.7 5.12 8-May-03 MW-112S Cs-134(pCiUL) -1.2 4.4 9.2 23-Jun-03 MW-112S Cs-1 34(pCVL) 0.29 2.61 4.98 24-Nov-03 MW-112S Cs-134(pCiJL) 1.79 5.49 10.6 21-Jan-04 MW-112S Cs-134(pCIIL) 1.51 1.88 3.7 1-Apr-04 MW-112S Cs-1 34(pCUL) 1.16 2.38 3.26 20-Jul-04 MW-112S Cs-134(pCilL) -2.29 2.11 3.33 19-Oct-04 MW-112S Cs-137(pCIIL) -6.84 8 13 1-Feb-02 MW-112S Cs-137(pCtIL) -1.3 1.99 3.35 29-Jul-02 MW-112S Cs-137(pCUL) -1.08 1.21 1.96 29-Aug-02 MW-112S Cs-137(pCt/L) 0.501 1.64 3.01 7-Nov-02 MW-112S Cs-137(pCllL) -0.289 1.18 2.11 23-Jan-03 MW-112S Cs-137(pCilL) 0.423 2.64 4.92 8-May-03 II of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l 2-Sigma Actual l Analysis Well ID Nuclide/Analyte (unit) l Net Concentration J TPU MDC Date MW-112S Cs-137(pCVL) -0.1 3.8 [ 7.5 23-Jun-03 MW-112S Cs-137(pCUL) 1.04 2.54 4.87 24-Nov-03 MW-112S Cs-137(pCVL) -2.77 4.8 8.17 21-Jan-04 MW-112S Cs-137(pCUL) -0.335 1.98 3.44 1-Apr-04 MW-112S Cs-137(pCi/L) 0 2.15 4.43 20-Jul-04 MW- 12S Cs-1 37(pCi/L) 0.452 1.73 3.26 19-Oct-04 MW-112S Eu-1 52(pCUL) -2.57 19 34 1-Feb-02 MW-112S Eu-152(pCUL) -1.19 4.7 8.33 29-Jul-02 MW-112S Eu-I 52(pCVL) -2.18 3.16 5.29 29-Aug-02 MW-1 12S Eu-1 52(pCUL) 0.354 4.17 7.44 7-Nov-02 MW-112S Eu-I 52(pCUL) -2.03 l 3.48 5.84 23-Jan-03 MW-112S Eu-152(pCUL) -0.342 6.56 11.7 8-May-03 MW-112S Eu-152(pCVL) -3.1 8.6 16 23-Jun-03 MW-112S Eu-1 52(pCUL) 0.205 5.29 9.62 24-Nov-03 MW-112S Eu-t 52(pCVL) -11.6 11.8 19.1 21-Jan-04 MW-112S MW-112S MW-112S Eu-t 52(pCI/L) Eu-152(pCUL) Eu-152(pCIIL) 3.51 0.143 6.1 J 5.91 5.48 11.4 11 9.35 9.94 1-Apr-04 20-Jul-04 19-Oct-04 MW-112S Eu-154(pCVL) -3.38 20 39 1-Feb-02 MW-112S Eu-154(pCVL) -0.846 1 4.05 8.07 29-Jul-02 MW-112S Eu-1 54(pCi/L) -1.81 j 3.82 6.67 I 29-Aug-02 MW-112S Eu-154(pCI/L) -3.51 5.5 9.32 7-Nov-02 MW-112S Eu-154(pCi/L) 0.945 3.89 7.63 23-Jan-03 MW-112S Eu-154(pCi/L) -1.5 5.83 11 8-May-03 MW-112S Eu-154(pCUL) 9.9 12.6 20 23-Jun-03 MW- 12S Eu-1 54(pCUL) 2.75 l 8.26 16.5 24-Nov-03 MW-112S Eu-154(pClVL) -2.56 l 15.9 29.8 21-Jan-04 MW-112S Eu-154(pCllL) -2.12 J 5.74 10 1-Apr-04 MW-112S Eu-154(pCI/L) 0.712 I 4.67 9.11 20-Jul-04 MW-112S Eu-154(pCIIL) -1.33 l 5.6 10.1 19-Oct-04 MW-112S Eu-155(pCVL) 17.1 j 27 49 1-Feb-02 MW-112S Eu-155(pCi/L) -3.59 j 3.37 5.4 29-Jul-02 MW-112S Eu-155(pCi/L) -0.0644 1 2.56 4.51 1 29-Aug-02 MW-112S Eu-I 55(pCl/L) -1.28  ! 3.77 6.48 l 7-Nov-02 MW-112S Eu-1 55(pCIlL) 0.36 I 2.31 4.13 I 23-Jan-03 MW-112S Eu-155(pCI/L) -2.11 1 4.81 1 8.11 I 8-May-03 MW-112S Eu-155(pCI/L) -11.7 j 13.6 26 l 23-Jun-03 MW-112S Eu-155(pCUL) -4.52 4.57 7.1 I 24-Nov-03 MW-112S Eu-155(pCUL) 4.67 l 9.4 17 21-Jan-04 MW-112S Eu-155(pCUL) -1.82 I 7.35 12.6 I 1-Apr-04 MW-112S Eu-155(pCi/L) -5.38 l 6.64 11.2 20-Jul-04 MW-112S Eu-155(pCIL.) 5.55 7.65 13.4 l 19-Oct-04 MW-112S Fe-59(pCVL) -6.9 1 13.8 30 23-Jun-03 MW-112S Gross Alpha(pCVL) 0.0668 1 0.318 0.788 l 6-Nov-02 MW-112S Gross Alpha(pCI/L) 0.382 j 0.403 0.685 j 21-Jan-03 MW-112S Gross Alpha(pCIIL) 0.356 0.403 l 0.717 1 8-May-03 MW- 12S Gross Alpha(pCUL) 1 0.28 1 1.06 2.1 1 23-Jun-03 MW-I 12S Gross Alpha(pCU/L) 0.213 j 0.43 0.931 23-Nov-03 MW-112S Gross Alpha(pCI/L) j 0.166 1 0.29 0.595 22-Jan-04 12 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT I 2-Sigma lActual Analysis Well ID NuclidelAnalyte (unit) Net Concentration TPU MDC Date MW-112S Gross Alpha(pCVL) 0.259 0.466 0.96 22-Apr-04 MW-112S Gross Alpha(pCVL) l '- '56-::: K '.. 1.1 l 1.77 22Jul-04 MW-112S Gross Alpha(pCVL) 0.0914 0.564 l 1.24 19-Oct-04 MW-112S Gross Beta(pCUL) l 3.61 1.49 2.51 6-Nov-02 MW-112S Gross Beta(pCUL) :1. .. .: 1.36 2.62 I 20-Jan-03 MW-112S Gross Beta(pCIIL) 1.21 1.26 2.58 7-May-03 MW-112S Gross Beta(pCI/L)  ; ,: 174 1,./2.02K. 2.7 23-Jun-03 MW-112S Gross Beta(pCVL) 2.62 1.39 2.55 22-Nov-03 MW-112S Gross Beta(pCVL) 0.914 1.2 2.5 20-Jan-04 MW-112S Gross Beta(pCUL) 0.778 1.17 2.38 22-Apr-04 MW-112S Gross Beta(pCUL) 0.641 0.944 J 1.97 22-Jul-04 MW-112S Gross Beta(pCUL) :t'.si.:.1:63 '.-;;". 1.18 I 2.29 19-Oct-04 MW-112S H-3 (pCVL) 144 175 1 286 [8-Oct-04 MW-112S H-3(pCilL) -173 130 240 11-Feb-02 MW-112S H-3(pCIIL) 50.6 170 277 27-Jul-02 MW-112S H-3(pCI/L) 59.2 160 259 18-Aug-02 MW-112S H-3(pCVL) 25.2 1 117 277 21-Nov-02 MW-112S H-3(pCUL) -89.8 j 115 293 25-Jan-03 MW-112S H-3(pCI/L) 28.5 107 249 1-May-03 MW-112S H-3(pClL) -100 220 340 23-Jun-03 MW-112S H-3(pCUL) -57.5 125 306 9-Nov-03 MW-112S H-3(pCUL) 159 119 253 14-Jan-04 MW-112S H-3(pCUL) 32 165 272 4-Apr-04 MW-112S H-3(pCUL) 102 169 277 19-Jul-04 MW-112S 1-131 (pCVL) -20 58 170 23-Jun-03 MW-112S K-40(pCUL) 21 54 _ 96 23-Jun-03 MW-112S La-140(pCI/L) 0 36 76 23-Jun-03 MW-112S Mn-54(pCUL) -3.08 7.9 14 1-Feb-02 MW-112S Mn-54(pCVL) 1.82 2.13 4.72 29-Jul-02 MW-112S Mn-54(pCUL) -1.01 1.27 2.06 29-Aug-02 MW-112S Mn-54(pCifL) -0.528 1.86 3.24 1 7-Nov-02 MW-112S Mn-54(pCUL) -0.791 1.43 2.39 23-Jan-03 MW-112S Mn-54(pCIUL) 0.301 2.59 4.94 8-May-03 MW-1 12S Mn-54(pCIUL) 1 3.8 7 23-Jun-03 MW-112S Mn-54(pCIUL) .- .,.36'.7?" s 2.47 5.36 24-Nov-03 MW-112S Mn-54(pCUL) 1 0.294 5.28 1 9.81 21-Jan-04 MW-112S Mn-54(pCVL) l 0 0 3.64 1-Apr-04 MW-112S Mn-54(pCVL) 1.69 1.82 J 3.57 20-Jul-04 MW-112S Mn-54(pCVL) J -0.0897 2.06 3.67 19-Oct-04 MW-112S Nb-94(pCi[L) l 5.63 7.6 16 1-Feb-02 MW-112S Nb-94(pCI/L) l -0.865 l 1.87 l 3.22 1 29-Jul-02 MW-112S Nb-94(pCUL) j -0.0692 1.2 2.19 29-Aug-02 MW-112S Nb-94(pCUL) -0.566 J 1.66 2.88 7-Nov-02 MW-1 12S Nb-94(pCI/L) -0.941  ! 1.17 1.87 23-Jan-03 MW-112S Nb-94(pCUL) I 1.9 2.4 4.98 8-May-03 MW-112S Nb-94(pCUL) ( -1.8 1 4.6 9 23-Jun-03 MW-112S Nb-94(pCifL) j 0.202 l 2.38l 4.47 24-Nov-03 MW-112S Nb-94(pCUL) 1.1 I 4.42 8.75 21-Jan-04 MW-112S Nb-94(pCl/L) 1.63 J 1.66 3.26 1-Apr-04 13 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 2-Sigma Actual Analysis Well ID NuclidelAnalyte (unit) Net Concentration TPU MDC Date MW-112S Nb-94(pCI/L) 0.816 1.73 3.22 20-Jul-04 MW-112S Nb-94(pCi/L) l 1.1 I 1.7 1 3.26 19-Oct-04 MW-112S Nb-95(pCUL) -2.7 10 l 20 23-Jun-03 MW-112S Ru-103(pCUL) -8.7 6 14 23-Jun-03 MW-112S Ru-106(pCUL) 1 38 73 23-Jun-03 MW-112S Sb-124(pCIIL) -7.4 16.2 37 23-Jun-03 MW-112S Sb-125(pCVL) 9.21 20 38 1-Feb-02 MW-112S Sb-125(pCUL) -4.5 10.6 21 23-Jun-03 MW-112S Se-75(pCUL) 0.9 5.2 9.5 23-Jun-03 MW-112S Sr-90(pCIUL) 5.49 1.28 0.634 18-Jan-04 MW-112S Sr-90(pCiIL) -0.0217 0.291 0.765 6-Apr-04 MW-112S Sr-90(pCIIL) . 0.697 x4 0.59 1.19 13-Jul-04 MW-112S Sr-90(pCI/L) 0.173 0.359 0.823 14-Oct-04 MW-112S Total U (pCitL) 0.01 55 0.00163 0.00978 30-Jan-04 MW-112S Zn-65(pCUL) -18.3 11.2 27 l 23-Jun-03 MW-112S Zr-95(pCUL) -2.9 10.4 1 21 1 23-Jun-03 MW-113S AcTh-228(pCi/L) l 2.5 14 1 27 j 23-Jun-03 MW-113S Ag-108m(pCI/L) -0.34 1.16 l 1.98 7-Nov-02 MW-113S Ag-108m(pCIIL) -0.855 1.33 2.19 23-Jan-03 MW-113S Ag-108m(pCiL) 0.79 1.75 3.4 8-May-03 MW-113S Ag-108m(pCU/L) -0.9 4.2 8 23-Jun-03 MW-113S Ag-108m(pCVL) 0.205 2.02 3.65 22-Nov-03 MW-113S Ag-108m(pCVL) 0.432 3.55 6.51 19-Jan-04 MW-113S Ag-108m(pCUL) -0.727 1.87 3.23 1-Apr-04 MW-113S Ag-1 08m(pCUL) -;~2. *i57  :,' 1.42 2.1 19-Jul-04 MW-113S Ag-108m(pCUL) 0.542 1.6 3.05 19-Oct-04 MW-113S Ag-110m(pCIIL) 2.6 5.6 I 10 23-Jun-03 MW-113S Am-241 (gamma)(pCUL) -12.4 22 [ 38 1-Feb-02 MW-113S Am-241 (gamma)(pCUL) 0.965 4.69 1 8.51 1 29-Jul-02 MW-113S Am-241 (gamma)(pCUL) -0.27 5.35 j 9.25 29-Aug-02 MW-113S Am-241 (gamma)(pCUL) -3.41 3.27 4.91 7-Nov-02 MW-113S Am-241 (gamma)(pCIIL) -1.4 6.68 11.5 23-Jan-03 MW-113S Am-241 (gamma)(pCI/L) 0.245 5.12 9.05 8-May-03 MW-113S Am-241 (gamma)(pCI/L) 3.5 10.9 19.4 22-Nov-03 MW-113S Am-241 (gamma)(pCUL) -1.41 14 24.2 19-Jan-04 MW-113S Am-241 (gamma)(pCIL) 0.435 15.2 26.7 1-Apr-04 MW-113S Am-241 (gamma)(pCVL) -0.0669 7.55 12.2 19-Jul-04 MW-113S Am-241(pCUL) -0.0131 0.0679 0.248 5-Apr-04 MW-113S Am-241-gamma(pCIIL 1.9 I 15.6 24.2 19-Oct-04 MW-113S Ba-140(pCUL) -35 26 79 23-Jun-03 MW-113S Be-7(pCVL) 43 44 67 j 23-Jun-03 MW-113S Boron(ug/L) 110 - 0.54 26-Jul-04 MW-113S Boron(ug/L) 130 - 0.54 r 29-Oct-04 MW-113S Ce-141(pCUL) 2.2 12 21 23-Jun-03 MW-113S Ce-144(pCUL) -9 26 47 l 23-Jun-03 MW-113S Co-57(pCUL) 8 28 48 23-Jun-03 MW-113S Co-58(pCUL) -4 6.4 14 23-Jun-03 MW-113S Co-60(pCUL) -0.398 6.6 13 1-Feb-02 MW-113S Co-60(pCIIL) 2.09 2.21 5.27 29-Jul-02 14 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT Well ID NuclidelAnalyte (unit) I I Net Concentration I 2-Sigma l Actual l Analysis TPU MDC Date MW-l1 3S Co-60(pCVL) 0.935 j 1.94 3.74 29-Aug-02 MW-113S Co-60(pCI/L) -0.055 1.59 1 2.96 7-Nov-02 MW-1 13S Co-60(pCi/L) 0.957 2.01 3.93 23-Jan-03 MW-1 13S Co-60(pCi/L) 2.09 2.29 5.31 8-May-3 l MW-113S Co-60(pCVL) 2.7 4.2 7.2 23-Jun-03 MW- 13S Co-60(pCVL) 0.587 2.42 5.05 22-Nov-03 MW-113S Co-60(pCUL) -1.92 5.18 9.29 .19-Jan-04 MW-113S Co-60(pCU/L) -0.406 2.22 3.99 l 1-Apr-04 MW-113S Co-60(pCI/L) 2.58 2.8 4.55 19-Jul-04 MW-113S Co-60(pCUL) 0.923 1.73 3.62 19-Oct-04 MW-113S Cr-51(pCVL) -22 I 74 140 23-Jun-03 MW-113S Cs-134(pCiUL) 3.25 6.4 13 1-Feb-02 MW-113S Cs-134(pCVL) 0.0822 1.89 3.41 l 29-Aug-02 MW-113S Cs-134(pCUL) . .7. 9. 1.75 3.47 7-Nov-02 MW-113S Cs-134(pCIIL) 0.135 1.87 3.41 23-Jan-03 MW-113S Cs-1 34(pCUL) 1.58 2.48 5.1 8-May-03 MW-113S Cs-134(pCVL) 2.3 4.6 8.1 23-Jun-03 MW-113S Cs-134(pCUL) 0.0732 3.62 6.59 22-Nov-03 MW-113S Cs-134(pCUL) -4.62 5.59 9.01 19-Jan-04 MW-113S Cs-134(pCU'L) -0.614 1.95 3.33 I-Apr-04 MW-113S Cs-134(pCVL) j 0.548 1.36 2.52 19-Jul-04 MW-113S Cs-1 34(pCVL) 0.324 2.02 3.73 19-Oct-04 MW- 13S Cs-137(pCI/L) 2.9 6.9 14 1-Feb-02 MW-113S Cs-1 37(pCi/L) 0.672 2.12 4.17 29-Jul-02 MW-113S Cs-I 37(pCIL) -0.559 1.77 3.04 29-Aug-02 MW-113S Cs-1 37(pCVL) -0.633 1.69 2.94 7-Nov-02 MW-113S Cs-1 37(pCVL) 1.06 1.9 3.51 23-Jan-03 MW-113S Cs-137(pCVL) -1.76 1.59 2.32 8-May-03 MW-113S Cs-137(pCIIL) -3.3 4.6 9.7 23-Jun-03 MW-I 3S Cs-137(pCIlL) -1.01 2.26 4 22-Nov-03 MW-113S Cs-137(pCI/L) 3.38 4.53 9.04 19-Jan-04 MW-113S Cs-137(pCi/L) -0.281 1.8 3.16 1-Apr44 MW-113S Cs-137(pCI/L) 1 -0.106 1.27 2.26 19-Jul-04 MW-113S Cs-1 37(pCI/L) 1 -0.496 1.86 3.28 19-Oct-04 MW-113S Eu-I 52(pCVL) 8.76 1B 35 1-Feb-02 MW-113S Eu-152(pCUL) i -1.9 6.01 1 10.5 29-Jul-02 MW-113S Eu-152(pCI/L) l 1.53 4.34 7.73 29-Aug-02 MW-113S Eu-152(pCUL) j 1.5 3.42 6.28 7-Nov-02 MW-113S Eu-152(pCUL) 3.08 4.32 8.01 23-Jan-03 MW-113S Eu-I 52(pCUjL) -1.01 5.69 9.94 8-May-03 MW-113S Eu-152(pCUQL) -1.1 9.4 17 23-Jun-03 MW-113S Eu-152(pCi/L) -1.99 6.74 11.7 22-Nov-03 MW-113S Eu-152(pCU/Lj -5.47 12.5 21 l 19-Jan-04 MW-113S Eu-152(pCI/L) l 5.03 9.81 1-Apr-04 MW-i13S Eu-1 52(pCIIL) 3.33 3.7 6.6 19-JuI-04 MW-113S Eu-152(pCVL) -0.713 5.87 9.94 19-Oct-04 MW-113S Eu-154(pClIL) 4.4 16 34 1-Feb-02 MW-113S Eu-154(pCI/L) 8.12 8.28 18.1 1 29-Jul-02 MW-113S Eu-154(pCI/L) -1.07 55.59 9.92 29-Aug-02 15 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddarm Neck, CT I2-Slgma Actual Analysis Well ID Nuclide/Analyte (unit) Net Concentration TPU MDC Date MW-113S Eu-154(pCI/L) 1.15 4.58 8.83 7-Nov-02 MW-113S Eu-154(pCI/L) 2.41 5.32 10.5 23-Jan-03 MW-113S Eu-154(pCUL) 0.461 6.31 12.7 8-May-03 MW-113S Eu-154(pCVL) -7.8 12A 29 23-Jun-03 MW-113S Eu-154(pCVL) -2.28 6.68 12.3 22-Nov-03 MW-113S Eu-154(pCiIL) -10.2 11 16.6 19-Jan-04 MW-113S Eu-154(pCllL) 0.512 4.77 9.21 1-Apr-04 MW-113S Eu-154(pCVL) -1.33 3.85 6.49 19-Jul-04 MW-113S Eu-154(pCVL) 1.12 5.24 10.3 19-Oct-04 MW-113S Eu-i 55(pCVL) + -10.3 25 I 42 1-Feb-02 MW-113S Eu-155(pCUL) .;.  :.75 .. . 4.32 1 8.5 29Jul-02 MW-1 13S Eu-1 55(pCUL) 1.83 3.92 6.85 29-Aug-02 MW-113S Eu-I 55(pClIL) -0.47 2.59 4.57 7-Nov-02 MW- 13S Eu-1 55(pCVL) 0.629 3.48 8.3 23-Jan-03 MW-113S Eu-I 55(pCUL) -5.38 3.89 5.83 8-May-03 MW-113S Eu-1 55(pCUL) 4.9 l 12.2 21 23-Jun-03 MW- 13S Eu-155(pCUL) 3.54 5.83 10.9 22-Nov-03 MW-I 13S Eu-I 55(pCVL) 1.68 10.5 18.8 19-Jan-04 MW-1 13S Eu-1 55(pCUL) -1.5 6.98 11.9 1-Apr-04 MW-113S Eu-155(pCVL) -0.381 ( 4.84 8.41 I 19-Jul-04 MW-113S Eu-155(pCUL) 5.65 7.51 13.9 19-Oct-04 MW-113S Fe-59(PCI/L) 3.8 12.2 23 23-Jun-03 MW-113S Gross Alpha(pCVL) 2.95 1.76 1.87 6-Nov-02 MW-113S Gross Alpha(pCIIL) 1.82 0.936 1.02 21-Jan-03 MW-113S Gross Alpha(pCUL) .ti0;892, ' 0.82 1.34 8-May-03 MW-113S Gross Alpha(pCVL) 0.3 1.68 l 3.2 23-Jun-03 MW-113S Gross Alpha(pCUL) 1.38 1.62 l3.12 22-Nov-03 MW-I 13S Gross Alpha(pCUL) 0.668 0.833 1.53 14-Jan-04 MW-113S Gross Alpha(pCUIL) 0.542 0.963 1.93 22-Apr-04 MW-113S Gross Alpha(pCVL) 00.989 1.26 2.38 22-Jul-04 MW-113S Gross Alpha(pCVL) 0.347 1.36 2.88 19-Oct-04 MW-113S Gross Beta(pCIL) 31.4 5.59 3.63 6-Nov-02 MW-113S Gross Beta(pCUL) 30.3 5.26 3.4 20-Jan-03 MW-113S Gross Beta(pCUL) 23.4 4.12 2.81 7-May-03 MW- 13S Gross Beta(pCUL) 16.8 3.2 2.9 23-Jun-03 MW-113S Gross Beta(pCIlL) 23.4 4.08 3.12 22-Nov-03 MW-113S Gross Beta(pCUL) 22.7 3.98 2.94 12-an-04 MW- 13S Gross Beta(pCIIL) 16.3 2.07 2.73 22-Apr-04 MW-113S Gross Beta(pCVL) 8.3 1.79 2.54 22-Jul-04 MW-113S Gross Beta(pCVL) 17.5 1.97 2.3 19-Oct-04 MW-113S H-3(pCVL) -111 130 240 11-Feb-02 MW-113S H-3(pCUL) 166 179 272 l 28-Jul-02 MW-113S H-3(pCUL) 159 170 263 18-Aug-02 MW-113S H-3(pCilL) .::L-160.-. 126 278 21-Nov-02 MW-113S H-3(pCI/L) 83.2 126 290 25-Jan-03 MW-113S H-3(pCUL) -,tz--49,:.. 114 248 1-May-03 f MW-113S H-3(pCUL) -150 220 340 23-Jun-03 MW-113S H-3(pCUL) 1 118 113 252 19-Nov-03 MW-113S H-3(pCIjL) 123 246 9-Jan-04 16 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 2-Sigma Actual Analysis Well ID Nuclide/Analyte (unit) Net Concentration TPU MDC Date MW-1 13S H-3(pCVL) 30.6  ; 157 260 5-Apr-04 MW-113S H-3(PCL) I .'..m18D . 163 263 19-Jul-04 MW-1 13S H-3(pCUL) 141 167 272 8-Oct-04 MW-113S I-131(pCUL) -56 82 1 170 23-Jun-03 MW-1I13S K-40(pCI/L) -5 48 100 23-Jun-03 MW-113S La-140(pCVL) -41 l 30 l 91 23-Jun-03 MW-113S Mn-54(pCIIL) 1.61 5.3 1 11 f 1-Feb-02 MW-1i13S Mn-54(pCUL) 1.22 2.98 5.85 29-Jul-02 MW-113S Mn-54(pCVL) l 0.172 - 1.89 3.41 29-Aug-02 MW-113S Mn-54(pCI/L) I 0.0113 I 1.75 3.13 7-Nov-02 MW-113S Mn-54(pCUL) 0.5 I 1.97 3.6 23-Jan-03 MW-113S Mn-54(pCVL) 0.976 1.87 3.95 8-May-03 MW-1I13S Mn-54(pCi/L) 1.1 4.4 8.2 1 23-Jun-03 MW-113S Mn-54(pCV/L) 1.79 2.53 5.2 22-Nov-03 MW-113S Mn-54(pCiL) 2.53 5.04 9.84 19-Jan-04 MW-113S Mn-54(pCU/L)  : 2 2.83 1-Apr-04 MW-113S Mn-54(pCUL) -0.167 1.33 2.32 19-Jul-04 MW-113S Mn-54(pCilL) 0.458 2.01 3.68 19-Oct-04 MW-113S Nb-94(pCUL) 3.14 6 12 1-Feb-02 MW-113S Nb-94(pCI/L) -0.0919 2.19 4.14 29-Jul-02 MW- 13S Nb-94(pCI/L) .; -. .91. 1.65 3.24 29-Aug-02 MW-113S Nb-94(pCV/L) -0.153 1.4 2.55 7-Nov-02 MW-113S Nb-94(pCU/L) -0.036 1.59 j 2.86 23-Jan-03 MW-113S Nb-94(pCi1L) -0.583 2.02 3.7 8-May-03 MW-1i13S Nb-94(pCUL) -0.8 3.6 7.3 23-Jun-03 MW-113S Nb-94(pCVL) 0.892 2.17 4.36 22-Nov-03 MW-113S Nb-94(pCUL) 2.14 4.75 9.32 19-Jan-04 MW-113S Nb-94(pCUL)  ; ?i' ',2.78 2.4 3.39 1-Apr-04 MW-1 13S Nb-94(pCI/L) 0.713 1.24 2.28 19-Jul-04 MW-1135 Nb-94(pCI/L) 0.312 1.79 3.27 19-Oct-04 MW-113S Nb-95(pCIIL) -6.4 8.6 19 23-Jun-03 MW-113S Ru-103(pCVlL) -1.4 7.4 14 23-Jun-03 MW-113S Ru-106(pCIlLj 11 36 67 23-Jun-03 MW-113S Sb-124(pCUL) 13.6 16.4 25 23-Jun-03 MW- 13S Sb-125(pCVIL) 2.54 18 33 1-Feb-02 MW-113S Sb-125(pCUL) -2.9 11.8 23 23-Jun-03 MW-1 13S Se-75(pCUL) 1.6 5.6 9.8 23-Jun-03 MW-113S Sr-89(pCI/L) -9.7 18.4 44 23-Jun-03 MW-I 13S Sr-90(pCU/L) 0.66 1.04 1.7 23-Jun-03 MW-113S Sr-90(pCi/L) 0.579 0.308 0.562 23-Nov-03 MW-113S Sr-90(pCIIL) 0.838 0.418 0.719 16-Jan-04 MW-113S Sr-90(pCVL)  :. 0.373 - 0.354 0.739 6-Apr-04 MW-113S Sr-90(pCVL) l '0.665. .-. l 0.602 1.23 13-Jul-04 MW-113S Sr-90(pCUL) 0.217 0.359 l 0.802 14-Oct-04 MW-113S Total U(pCilL) l 0.0716 0.0108 l 0.00978 19-Jan-04 MW-113S Zn-65(pCVL) 1.3 11.2 21 23-Jun-03 MW-113S Zr-95(pCUL) 0.2 1 8.6 I 17 23-Jun-03 MW-117S AcTh-228(pCUL) 1 -5.7 1 18 1 36 23-Jun-03 MW-117S Ag-108m(pCUL) I:2.-.-l.63 -:-l 1.39 2.62 l 7-Nov-02 17 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 2-Sigma Actual Analysis Well ID NuclidelAnalyte (unit) Net Concentration TPU MDC Date MW-117S Ag-108m(pCUL) -0.699 11.391 2.31 1 23-Jan-03 MW-117S Ag-108m(pCUL) -0.295 I 1.87 3.33 8-May-03 MW-117S Ag-108m(pCUL) -0.6 3 6 23-Jun-03 MW-117S Ag-108m(pCUL) 0.698 1.69 l 3.29 22-Nov-03 MW-117S Ag-1_08m(pCUL) 0.475 2.95 5.5 21-Jan-04 MW-117S Ag-108m(pCUL) 0.603 2.27 1 3.92 1-Apr-04 MW-117S Ag-108m pCUL) -0.686 2.03 3.04 4-Aug-04 MW-117S Ag-108m(pCIIL) -0.51 1.24 2.13 17-Oct-04 MW-1 17S Ag-110m(pCi/L) -5 7.4 15 23-Jun-03 MW-117S Am-241 .(gamma)(pCUL) -9.08 28 49 I1-Feb-02 MW-117S Am-241 (gamma)(pCUL) -0.842 6.3 11.2 29-Jul-02 MW-117S Am-241 (gamma)(pCIIL) 2.18 2.98 5.5 29-Aug-02 MW-117S Am-241 (gamma)(pCUL) 0.435 5.57 9.42 7-Nov-02 MW-117S Am-241 (gamma)(pCUL) 0.61 j 5.36 9.23 23-Jan-03 MW-117S Am-241 (gamma)(pCUL) -5.34 I 8.03 13.2 8-May-03 MW-117S Am-241 (gamma)(pCUL) -5.22 5.44 8.66 22-Nov-03 MW-117S Am-241 (gamma)(pCUL)I -17.9 16.5 22.8 1-Apr-04 MW-117S Am-241 (gamma)(pCUL) -2.76 18.3 27.5 4-Aug-04 MW-117S Am-241(pCUL) -0.0415 0.0364 0.27 5-Apr-04 MW-117S Am-241-gamma(pCVL) 0.857 9.09 13.5 17-Oct-04 MW-117S Ba-140(pCUL) 10 24 47 23-Jun-03 MW-117S Be-7(pCUL) -13 46 J 90 23-Jun-03 MW-117S Boron(ugIL) 68.5 - 0.54 22-Jul-04 MW-117S Boron(ug/L) 71.8 - 0.54 22-Oct-04 MW-117S Ce-141(pCUL) -10.1 12.6 24 23-Jun-03 MW-117S Ce-144(pCUL) -19 28 52 23-Jun-03 MW-117S Co-57(pCUL) 14 28 47 23-Jun-03 MW-117S Co-58(pCVL) -2 I 6.6 12 I 23-Jun-03 MW-117S Co-60(pCUL) -5.13 6 11 1-Feb-02 MW-117S Co-60(pCIIL) -2.33 3.42 5.61 29-Jul-02 MW-117S Co-60(pCIIL) -0.454 1.97 3.51 29-Aug-02 MW-I 17S Co-60(pCI/L)  ::276 1 1.86 3.94 7-Nov-02 MW-117S Co-60(pCI/L) .i2.44:' i- - 2.01 4.11 23-Jan-03 MW-117S Co-60(pCIIL) 0.508 2.65 5.23 8-May-03 MW-117S Co-60(pCIIL) -3.3 l 5 11 23-Jun-03 MW-117S Co-60(pCUiL) -0.0708 1.99 4.04 22-Nov-03 MW-117S Co-60(pCUL) -2.08 4.05 7.18 21-Jan-04 MW-117S Co-60(pCUL) -1.42 2.34 4.01 1-Apr-04 MW-117S Co-60(pCUL) I 2.12 2.22 4.71 4-Aug-04 MW- 17S Co-60(pCVL) -0.647 1.42 2.39 17-Oct-04 MW-117S Cr-51(pCUL) -26 90 l 170 23-Jun-03 MW-117S Cs-134(pCVL) -3.71 5.2 8.6 1-Feb-02 MW-117S Cs-134(pCUL) -0.357 1.93 3.39 29-Aug-02 MW-117S Cs-134(pCIL) -1.5 1.99 3.25 7-Nov-02 MW-117S Cs-134(pCi/L) 1.22 1.92 1 3.61 23-Jan-03 MW-117S Cs-134(pCUIL) -1.71 2.98 55.07 8-May-03 MW-117S Cs-134(pCUlL) 0.6 4.2 l 7.9 23-Jun-03 MW- 17S Cs- 34(pCUL) 1.36 2.36 4.87 22-Nov-03 MW-117S Cs-134(pCUL) -2.14 3.81 l 6.44 21-Jan-04 18 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l 2-Sigma l Actual Analysis Well ID Nuclide/Analyte (unit) l Net Concentration J TPU MDC Date MW-117S Cs-134(pCVL) 1 1.65  ; 2.3 J 4.45 1-Apr-04 MW-117S Cs-134(pCUL) 0.0363 l 1.96 j 3.54 4-Aug-04 MW-117S Cs-134(pCV/L) 0.316 l 1.45 I 2.54 17-Oct-04 MW-117S Cs-137(pCiVL) -4.64 5.8 9.3 1-Feb-02 MW-117S Cs-1 37(pCVL) 0.727 2.42 4.84 29-Jul-02 MW-117S Cs-137(pCVL) -0.799 1.48 2.47 29-Aug-02 MW-117S Cs-137(pCUL) -0.998 2.01 3.43 7-Nov-02 MW-117S Cs-1 37(pCUL) -0.58 1.56 l 3.21 23-Jan-03 MW-117S Cs-1 37(pCUL) -0.898 2.51 4.38 8-May-03 MW-117S Cs-1 37(pCi/L) -3.5 4.2 9.3 23-Jun-03 MW-117S Cs-137(pCUL) 0.645 2.13 4.21 22-Nov-03 MW-117S Cs-137(pCUL) -1.5 3.85 6.78 21-Jan-04 MW-117S Cs-137(pCIIL) -2.67 2.36 3.76 1-Apr-04 MW-117S Cs-137(pCIIL) -0.372 2.37 4.08 4-Aug-04 MW-117S Cs-137(pCI/L) 1.2 1.22 2.3 17-Oct-04 MW-117S Eu-152(pCUL) -2.4 14 24 1-Feb-02 MW-117S Eu-152(pCI/L) 5.49 7.27 14 29-Jul-02 MW-117S Eu-152(pCi/L) 2.51 I 3.66 6.85 29-Aug-02 MW-117S Eu-152(pCI/L) -0.179 4.15 7.13 7-Nov-02 MW-117S Eu-I 52(pCUL) -1.78 4.32 7.31 23-Jan-03 MW-117S Eu-I 52(pCVL) -1.8 6.32 10.9 8-May-03 MW-117S Eu-152(pCUL) 5.7 9.5 17 23-Jun-03 MW-117S Eu-152(pCUL) 0.0293 5.85 10.4 22-Nov-03 MW-117S Eu-152(pCUL) 7.67 9.71 19 21-Jan-04 MW-I 17S Eu-1 52(pCUL) 3.21 1 7.2 12.6 1-Apr-04 MW-117S Eu-152(pCUL) -0.0575 6.31 11.2 4-Aug-04 MW-117S Eu-152(pCi/L) 1.42 3.98 I 6.72 17-Oct-04 MW-117S Eu-154(pCilL) 3.04 13 25 1-Feb-02 MW-117S Eu-154(pCUL) -5.44 10 17.1 29-Jul-02 MW-117S Eu-154(pCi/L) 0.194 4.56 8.59 29-Aug-02 MW-117S Eu-154(pCI/L) 1.04 4.71 8.91 7-Nov-02 MW-117S Eu-154(pCllL) -1.06 5.56 9.79 23-Jan-03 MW-117S Eu-154(pCU/L) -1.44 7.07 13.1 5-May-03 MW-117S Eu-154(pCUL) 2.7 11.8 23 23-Jun-03 MW-117S Eu-154(pCUL) 0.685 5.56 11.6 22-Nov-03 MW-117S Eu-154(pCI/L) 4.68 10.5 23.4 I 21-Jan-04 MW-117S Eu-154(pCI/L) 0.292 4.71 9.27 1-Apr-04 MW-1 17S Eu-154(pCI/L) 2.22 5.7 11.4 4-Aug-04 MW-117S Eu-154(pCI/L) 3.79 3.98 6.23 17-Oct-04 MW-117S Eu-155(pCtL) 5.89 16 29 1-Feb-02 MW-117S Eu-155(pCUL) 1.31 4.79 8.79 29-Jul-02 MW-117S Eu-i 55(pCUL) 0.278 2.77 4.8 29-Aug-02 MW-117S Eu-1 55(pCUL)  : ... 3.97 7.15 7-Nov-02 MW-117S Eu-1 55(pCUL) -2.26 3.8 6.38 1 23-Jan-03 MW-117S Eu-155(pCIIL) 5.06 5.6 10.4 j 8-May-03 MW-117S Eu-I 55(pCJIL) -3.2 13.2 24 I 23-Jun-03 MW-1t7S Eu-155(pCVIL) 0.321 4.03 7.39 22-Nov-03 MW-1t7S Eu-1 55(pCUL) . -2.4 l T 6.45 11.3 21-Jan-04 MW-117S Eu-155(pCIL) -4.09 1 8.64 15 1-Apr-04 19 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT 2-Sigrnal Actual lAnalysis Well ID NuclidelAnalyte (unit) Net Concentraton TPU MDC_ Date MW-117S Eu-155(pCI/L) -2.22 9.14 15.1 1 4-Aug-04 MW-117S Eu-1 55(pCUL) -0.664 4.56 7.92 17-Oct-04 MW-117S Fe-59(pCI/L) -5.2 11.6 26 23-Jun-03 MW-117S Gross Alpha(pCI/L) 1.59 1.07 T 1.26 6-Nov-02 MW-117S Gross Alpha(pCUL) 0.715 0.759 1 1.27 21-Jan-03 MW-117S Gross Alpha(pCVL)  ; -. 0.902 0.833 j 1.34 7-May-03 MW-117S Gross Alpha(pCUL) 3.8 2.2 2.9 23-Jun-03 MW-117S Gross Alpha(pCUL) 0.467 1.02 2.25 22-Nov-03 MW-117S Gross Alpha(pCU) . '.:!.31;:1.31 2.24 22-Jan-04 MW-117S Gross Alpha(pCUL) 1.21 1.49 2.97 22-Apr-04 MW-117S Gross Alpha(pCVL) 0.41 0.837 1.44 29-Jul-04 MW-117S Gross Alpha(pCVL) 0.425 0.678 1.33 14-Oct-04 MW-117S Gross Beta(pCiIL) 8.36 2.28 3.05 6-Nov-02 MW-117S Gross Beta(pCIUL) 7.66 2.11 2.86 20-Jan-03 MW-117S Gross Beta(pCUL) 8.13 2.24 3.05 7-May-03 MW-117S Gross Beta(pCUL) 11.66 1.94 2.1 23-Jun-03 MW-117S Gross Beta(pCIIL) 9.49 2.77 3.97 22-Nov-03 MW-117S Gross Beta(pCI/L) 9.65 2.78 3.96 20-Jan-04 MW-117S Gross Beta(pCiUL) 5.41 1.8 3.23 22-Apr-04 MW-117S Gross Beta(pCiVL) 7.28 1.55 2.3 29-Jul-04 MW-117S Gross Beta(pCUL) 6.91 1.42 2.17 14-Oct-04 MW-117S H-3(pCUL) -234 120 240 11 -Feb-02 MW-117S H-3(pCVL) -74.6 156 272 7 28-Jul-02 MW-117S H-3(pCUL) 107 165 261 18-Aug-02 MW-I17S H-3(pCUL) 99.1 122 279 21-Nov-02 MW-117S H-3(pCVL) 34 123 294 25-Jan-03 MW-117S H-3(pCVL) 61.5 109 249 1-May-03 MW-117S H-3(pCI/L) -80 220 340 23-Jun-03 MW-117S H-3(pCi/L) 55.3 110 253 9-Nov-03 MW-117S H-3(pCVL) 31.1 112 255 14-Jan-04 MW-117S H-3(pCIL) 33.3 171 283 4-Apr-04 MW-117S H-3(pCUL) 25.1 194 9 324 30-Jul-04 MW-117S H-3(pCUL) 140 215 l 352 i 7-Oct-04 MW-117S 1-131(pCVL) -20 108 200 l 23-Jun-03 MW-117S K-40(pCUL) -37 40 100 l 23-Jun-03 MW-117S La-140(pCVL) 12 28 54 l 23-Jun-03 MW-117S Mn-54(pCUL) -0.196 4.6 l 8.5  ! 1-Feb-02 MW-117S Mn-54(pCI/L) 0.635 3.55 j 6.93 29-Jul-02 MW-117S Mn-54(pCIIL) -0.735 1.92 1 3.27 29-Aug-02 MW-117S Mn-54(pCUL) 0.0975 2.01 l 3.56 7-Nov-02 MW-117S Mn-54(pCiIL) -0.499 I 1.8 I 3.16 23-Jan-03 MW-117S Mn-54(pCVL) 1.6 2.98 1 5.74 8-May-03 MW-117S Mn-54(pCVL) -0.4 3.8 7.7 23-Jun-03 MW-117S Mn-54(pCi/L) -1.04 2.24 3.85 22-Nov-03 MW-117S Mn-54(pCi/L) 2.62 3.35 l 7.51 l 21-Jan-04 MW-117S Mn-54(pCiL) -0.03 2.5 1 3.89 l 1-Apr-04 MW-117S Mn-54(pCiUL) -1.04 2.18 1 3.83 1 4-Aug-04 MW-117S Mn-54(pCl/L) -0.0955 1.6 1 2.36 1 17-Oct-04 MW-11lS Nb-94(pCI/L) -4.63 4.6 l 7.5 1-Feb-02 20 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT Il 2-Sigma Actual Analysis Well ID NucildelAnalyte (unit) l Net Concentratilonl TPU lMDC l Date MW-117S Nb-94(pCVL) 0.368 2.31 I 4.63 29-Jul-02 MW-117S Nb-94(pCVL) -0.0923 1.44 2.58 29-Aug-02 MW-117S Nb-94(pCVL) 0.2 1.61 2.95 7-Nov-02 MW-117S Nb-94(pCVL) 0.00816 1.67 2. 37-an-03 MW-117S Nb-94(pCVLj 0.72 2.6 4.93 8-May-03 MW-117S Nb-94(pC/L) 2.4 l 3.4 5.5 23-Jun-03 MW-17S Nb-94(pCVL) -1.41 I 2.07 3.5 22-Nov-03 MW-117S Nb-94(pCVL) 1.23 3.36 7 21-Jan-04 MW-117S Nb-94(pCUL) 0.259 1.91 3.48 1-Apr-04 MW-117S Nb-94(pCUL) 1.22 1.93 3.64 4-Aug-04 MW-117S Nb-94(pCi/L) -0.0533 1.2 2.07 17-Oct-04 MW-117S Nb-95(pCUL) 0.3 7.4 1 14 23-Jun-03 MW-117S Ru-103(pCIIL) 2.5 5.6 9.9 23-Jun-03 MW-117S Ru-106(pCIIL) 1 38 1 73 23-Jun-03 MW-I17S Sb-124(pCilL) -7.4 1 14.8 35 23-Jun-03 MW-117S Sb-125(pCi/L) 3.66 l 13 1 23 1-Feb-02 MW-117S Sb-125(pCi/L) 3.6 11.6 21 23-Jun-03 MW-117S Se-75(pCi/L) -3.2 5.6 11 23-Jun-03 MW-117S Sr-89(pClVL) -1 20 45 23-Jun-03 MW-117S Sr-90(pCllL) 1.28 0.602 0.812 24-Jan.03 MW-117S Sr-90(pCVL) >1.41 i - 0.882 1.53 7-May-03 MW-Il7S Sr-90(pCIVL) . 1.08 1.7 23-Jun-03 MW-117S Sr-90(pCIlL) 1.42 0.443 0.57 I 23-Nov-03 MW-117S Sr-90(pCUL) 0.765 0.331 0.512 18-Jan-04 MW-117S Sr-90(pCUL) 9.°.196 ' - 0.457 1.09 6-Apr-04 MW-117S Sr-90(pCVL) ' .X <.'.0791

                                                        . 0.516           0.952    17-Jul-04 MW-117S             Sr-90(pCVL)            P0.813' '. -.' 0.617             1.18    14-Oct-04 MW-117S            Total U(pCUL)       "Q.'; ,0                 0.00113   0.00978 30-Jan-04 MW-i17S            Zn-65(pCVL)                    17               20        34     23-Jun-03 MW-117S             Zr-95(pCUL)                 -3.7                9        19     23-Jun-03 MW-13       Am-241 (gamma)(pCl/L)             1.51           1 24           42      1-Feb-02 MW-13       Am-241 (gamma)(pCUL)             0.573               2.89      5.17    29-Jul-02 MW-13             Co-60(pCUL)                   1.4               5.9       13      1-Feb-02 MW-13             Co-60(pCUL)                 1.01               2.24      5.16    29-Jul-02 MW-13             Cs-134(pCIL)               -2.37                5.8       10      1-Feb-02 MW-13             Cs-137(pCiIL)             -0.0769               6.8       13      1-Feb-02 MW-13             Cs-I 37(pCUL)               1.09               2.51      5.02 129-Jul-02 MW-13             Eu-152(pCiL)                3.03                20        38      1-Feb-02 MW-13             Eu-152(pCI/L)               1.73                5.7      10.9    29-Jul-02 MW-13             Eu-I 54(pCi/L)              4.97                18        38      1-Feb-02 MW-13             Eu-154(pCt/L)               5.32               8.39      18.3    29-Jul-02 MW-13             Eu-155(pCUL)                8.87                24        43     1-Feb-02 MW-13             Eu-155(pCUL)                1.54           j 4.53        8.06    29-Jul-02 MW-13               H-3(pCI/L)                -189           1 130         240     11-Feb-02 MW-13               H-3(pCIIL)               -57.7               157       267     28-Jul-02 MW-13             Mn-54(pCUL)                -1.84           1 6.3          12      1-Feb-02 MW-13             Mn-54(pCUL)                0.517               2.81      5.59    29-Ju-02 MW-13             Nb-94(pCIL)                0.         1 5.59                     2-Jul-02 MW-13             Nb-94(pCIUL)                1.62               2.39      5.05    29-Jul-02 21 of 24

Table A-i Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT I 2-Sigma Actual Analysis Well ID Nucilde/Analyte (unit) Net Concentration I TPU MDC Date MW-13 Sb-125(pCVL) I -0.343 1 19 1 34 I 1-Feb-02 MW-2 Ag-108m(pCUL) 0.0793 J 1.33 j 2.35 j 23-Jan-03 MW-2 Ag-108m(pCVL) 0.666 1.61 2.93 j 4-Aug-04 MW-2 Ag-108m(pCUL) -0.0755 L 1.26 2.13 17-Oct-04 MW-2 Am-241 (gamma)(pCIIL) 0.308 j 2.11 3.21 23-Jan-03 MW-2 Am-241 (gamma)(pCUL) -2.02 9.69 17.3 4-Aug-04 MW-2 Am-241(pCUL) -0.00733 0.0147 0.175 30-Jan-03 MW-2 Am-241-gamma(pC L) 0.474 7.73 13.3 17-Oct-04 MW-2 Boron(uglL) 15.5 - 0.54 22-Jul-04 MW-2 Boron(ug/L) j 18 - 0.54 22-Oct-04 MW-2 C-14(pCVL) j -0.481 3.55 7.89 15-Jan-03 MW-2 Cm-242(pCi/L) 0 0.108 0.12 30-Jan-03 MW-2 Cm-243,244(pCUIL) 0 0.0901 0.0997 30-Jan-03 MW-2 Co-60(pCVL) -0.0304 1.74 3.26 23-Jan-03 MW-2 Co-60(pCVL) j 1.08

                                             -0.168 3.74 1 3.73 1.48 4-Aug-04 2.62 l 17-Oct-04 MW-2             Co-60(pCi/L)

MW-2 Cs-1 34(pCi/L) -0.938 I 2.02 3.42 23-Jan-03 MW-2 Cs-1 34(pCUL) j 0.129 l 1.89 3.52 4-Aug-04 MW-2 Cs-134(pCUL) 0.507 1.44 2.59 17-Oct-04 MW-2 Cs-1 37(pCIIL) 0.797 1.64 3.09 23-Jan-03 MW-2 Cs-1 37(pCIIL) 0.322 1.88 3.51 4-Aug-04 MW-2 Cs-137(pCU/L) j £. 1.73' 1.3 2.49 17-Oct-04 MW-2 Eu-1 52(pCIIL) J -0.631 4.22 7.36 23-Jan-03 MW-2 Eu-1 52(pCiIL) 3.88 j 5.35 9.78 4-Aug-04 MW-2 Eu-152(pCIIL) 1.72 3.62 6.39 17-Oct-04 MW-2 Eu-154(pCIlL) 3.31 5.19 10.4 23-Jan-03 MW-2 Eu-154(pCUL) 1.6 4.82 9.56 4-Aug-04 MW-2 Eu-154(pCUL) -0.447 3.89 6.94 17-Oct-04 MW-2 Eu-155(pCVL) 25 -, 3.26"-. 3.09 5.57 23-Jan-03 MW-2 Eu-1 55(pCUL) -1.68 6.8 11.9 4-Aug-04 MW-2 Eu-155(pCUL) 1.89 1 5.17 8.78 17-Oct-04 MW-2 Fe-55(pCUL) -8.15 3.68 5.72 1-Feb-03 MW-2 Gross Alpha(pCiIL) -0.06 j 0.334 0.967 21-Jan-03 MW-2 Gross Alpha(pCUL) 0.416 T 0.66 1.29 1.39 28-Jul-04 14-Oct-04 MW-2 Gross Alpha(pCUL) J 1049.8X04i. 0.797 MW-2 Gross Beta(pCUL) 2.75 1.48 2.7 20-Jan-03 MW-2 Gross Beta(pCi/L) 1 4.43 l 1.43 2.46 28-Jul-04 MW-2 Gross Beta(pCUL) 3.47 l 1.29 2.27 14-Oct-04 MW-2 H-3(pCI/L) I -229 134 291 25-Jan-03 MW-2 H-3(pCI/L) -251 229 397 2-Aug-04 MW-2 H-3(pCi/L) - 439 193 300 7-Oct-04 MW-2 Mn-54(pCtlL) 7 0.453 1.91 3.47 23-Jan-03 MW-2 Mn-54(pCU/L) - -0.154 1.92 1 3.47 4-Aug-04 MW-2 Mn-54(pCVL) j 0.0633 1.25 2.2 17-Oct-04 MW-2 Nb-94(pCUL) -0.987 1.66 2.74 234-an-03 MW-2 Nb-94(pCUL) 1 1.3398 1.66 I 3.28 34-Aug-04 MW-2 Nb-94(pCVL) -0.922 l 1.14 1.89 I 17-Oct-04 MW-2 NI-63(pCVL) 1.51 l 2.75 3.83 [ 1-Feb-03 MW-2 Pu-238(pCitL) 0.0295 l 0.0753 0.176 23-Jan-03 22 of 24

Table A-1 Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l2-Slgmna lActual lAnalysis Well ID NuclidelAnalyte (unit) Net Concentration TPU MDC Date MW-2 Pu-239,240(pCU/L) 0 0.0902 0.0998 23-Jan-03 2 MW-2 Pu-241(pCUL) 11.2 3.62 6.34 31-Jan-03 MW-2 Sr-90(pCVL) .,'0.413 -{ 0.315 0.539 24-Jan-03 MW-2 Sr-90(pCUL) -0.131 I 0.374 1.02 17-Jul-04 MW-2 Tc-99(pCUIL) 2.65 l 8.06 11.4 I 24-an-03 MW-3 Ag-iO8m(pCi/L) 0.574 I 1.45 2.58 19-Jul-04 MW-3 Ag-1 08m(pCl/L) 0.548 1.59 2.68 I 17-Oct-04 MW-3 Am-241 (gamma)(pCVL)I -12.4 17.4 19.3 1 19-Jul-04 MW-3 Am-241-gamma(pCUIL) 3.79 9.42 15.6 J17-Oct-04 MW-3 Boron(ugIL) 5.67 - 0.54 26-Jul-04 MW-3 Boron(ugIL) 7.95 - 0.54 22-Oct-04 MW-3 Co-60(pCVL) 0.383 1.49 2.78 19-Jul-04 MW-3 Co-60(pCVL) 1.11 l 1.51 2.69 17-Oct-04 MW-3 Cs-134(pCi/L) 0.0365 [1.69 2.9 19-Jul-04 MW-3 Cs-134(pCilL) -0.1 1.65 2.86 17-Oct-04 MW-3 Cs-I 37(pCI/L) -0.627 l 1.48 l 2.47 19-Jul-04 MW-3 Cs-137(pCiUL) 1.14 1.5 2.76 17-Oct-04 MW-3 Eu-152(pCl/L) -0.884 4.31 7.42 19-Jul-04 MW-3 Eu-1 52(pCilL) -2.57 4.64 7.54 17-Oct-04 MW-3 Eu-154(pCi/L) -2.25 4.05 6.85 19-Jul-04 MW-3 Eu-154(pCiIL) -0.879 3.67 6.56 17-Oct-04 MW-3 Eu-155(pCUL) -1.4 6.34 10.4 19-ul-04 MW-3 Eu-155(pCVL) 2.81 5.86 10.4 J17-Oct-04 MW-3 Gross Alpha(pCUL) -0.168 0.763 1.81 J 26-Jul-04 MW-3 Gross Alpha(pCUL) 0.483 0.954 1.93 J14-Oct-04 MW-3 Gross Beta(pCVL) .:,.788 . 0.765 1.49 26-Jul-04 MW-3 Gross Beta(pCUL) '1:53 .", 1.33 2.58 14-Oct-04 MW-3 H-3(pCIIL) 15.6 147 245 20-Jul-04 MW-3 H-3(pCUL) 100 167 274 7-Oct-04 MW-3 Mn-54(pCUL) 0.202 1.39 2.55 19-Jul-04 MW-3 Mn-54(pCUL) -1.81 1.42 2.2 17-Oct-04 MW-3 Nb-94(pCllL) -0.436 1.4 2.34 19-Jul-04 MW-3 Nb-94(pCVL) 0.611 1.32 1 2.38 17-Oct-04 MW-3 Sr-90(pCUL) 0.582 0.599 I 1.24 13-Jul-04 Supply Well B Sr-90(pCUL) 1.02 1 0.35 0.45 j 30-Jan-02 Supply Well B Sr-90(pCUL) I 0.199 1 0.289 I 0.579 24-Jan-03 Supply Well E Sr-90(pCUL) I .Vr$0.366 ; I 0.34 1 0.56 1 30-Jan-02 TW-1 Am-241 (gamma)(pCUL) 5.25 1 14 26 1-Feb-02 TW-1 Am-241 (gamma)(pCUL) -0.569 9.48 16.5 29-Jul-02 TW-1 Co-60(pCVL) -4.58 9.4 17 1-Feb-02 TW-1 Co-60(pCVL) 1.05 4.01 7.84 29-Jul-02 TW-1 Cs-134(pCVL) -3.77 J 8.3 15 1-Feb-02 TW-1 Cs-137(pCUL) -12.2 9.3 13 1-Feb-02 TW-1 Cs-137(pCVL) 2.25 3.16 6.19 29-Jul-02 TW-1 Eu-1 52(pCVL) -2.26 1 23 42 l 1-Feb-02 TW-1 Eu-152(pCIIL) 1.77 l 7.1 13.1 l 29-Jul-02 TW-1 Eu-154(pCUL) -2.26 l 26 53 l 1-Feb-02 TW-1 Eu-154(pCUIl) 3.94 7 9.84 19.7 l 29-Jul-02 _WA-I Eu-1 55(pCUIL) 5.35 J 18 33 1-Feb-02 23 of 24

Table A-I Peninsula Evaluation Laboratory Analytical Data Reported for Groundwater From HNP Peninsula Wells Connecticut Yankee Haddam Neck Plant Haddam Neck, CT l 2-Sigma Actual. Analysis Well ID NuclidelAnalyte (unit) Net Concentration TPU MDC Date TW-1 Eu-1 55(pCi/L) -0.954 6.82 122 29-Jul-02 TW-1 H-3(pCi/L) -342 120 250 11 -Feb-02 TW-1 H-3(pCI/L) -13.3 161 267 28-Jul-02 TW-1 Mn-54(pCiVL) 5.97 [9.9 21 1-Feb-02 T1W-1 Mn-54(pCVL) -4.21 3.84 5.98 29-Jul-02 TW-I Nb-94(pCVL) 0.713 8.3 I 17 1-Feb-02 TW-1 Nb-94(pCVL) 1.21 3.03  ! 5.87 29-Jul-02 TW-I Sb-125(pCI/L) 21.5 23 48 1 -Feb-02 TW-1 Rep. Eu-155(pCi/L) -'22.8 15 30 I1-May-02 Notes: Results In BOLD print exceed the sample MDC Shaded results exceed the 2-sigma total propagated uncertainty for the analysis 24 of 24

Table A-2 Peninsula Evaluation Summary of Historical Groundwater Detections Compared to MCLs Connecticut Yankee Haddam Nock Plant Haddam Neck, CT Fraction Isotope Equivalent of Non. Equivalent Fraction of Concentration Net Analyvls Non-Dose Doss Concantrationil Equivalent Sum-of-Wel ID Nudlde/Analyte (unUit Concwntration Actual MDC -Date MCL MCL (pCUlL) Concentration Fractions MW -1105 Gross Beta(pCULI Z 79 0.88 'T13Fe-02 0 .CWs GrossBetatpCUL) 4.07 2.81 16uP02 50 O.C8 /L_ H43(pCtl) 2980 288 274ut-02 i2000 G 0.15 Pu-241(pCUL) G .91 6.84 14Aug-02 3D0 0.02 H4"pCUL) 1470 259 18-Aug-02 2000 OO 0.07 0.17 Grass Beta(pCULI 8.51 2.68 21-A 2 50 0.13 4Wr -17, 1-3(pCUL) 2390 278 14-Nov-02  ; 20000 0.12 0.12 Gross Beta(pCUL) 4.39 2.62 5-Dec.02 50 0.09

• Gross Beta(pCVL) 4.28 2.59 20-Jan403 50 0.09 R e&'j H-3(pCtL) 2050 289 25-Jan-03 E 20000 0.1,.

Pu-241(pCUL& 13.2 8.16 31-Jan-03  ; 300 0.04 - 0.15 Gross Bota(pClL) 7.47 2.74 74May-03 50 0.155 H-3(pCtL) 1430 258 8-ay-03 t-M_ F7=c9r- MA 20000 0.07 04J7 H-3(pCUL) 1370 330 25-Jun-03 t 20000 0.07 0.07 Gross Balot(pC'L) 7.3 2.7 254un-03 50 0.15 . 2. -. H-3(pCUL) 1420 297 -NOV-03 ~ 1jj __'] 20000 0.07 0.07 Gross fBaapCVLI 3.99 2.73 22-NOv-03 50 00.0 T7 75i H-3(pCVL) 1290 255 14-Jan-04 klPys-f 1 20000 O.0G 0.08 Gross Bala(pCIL) 4.7 2.58 20-Jan-04 0 0.09 - Total U og/LI 0.0122 0.00978 30.Jan404 30 0°00 Pr ' H-3pClL) 2050 262 3-Apr-04 E_______- J 20000 0.10 0.10 Grass BelalPCltI 1.88 1.27 13-Apr.04 50 0.04  : H-3pCUL) 1010 310 194u-14 ts ^-trar V 20000 035 0.05 Grass Beta(pCUL) 435 2.05 22-4i04 50 0.09 r -- TVT =.5 _.3 H-3{pCVL) 1670 254 8-Oc-04 i 20000 0.08 0.08 Gross Bela(pCUL. 4.48 2.75 19-c4-04 50 009 1-$ i MW-1I1S Gross BsMa(pCVL) 4.23 0428 13-Feb-02 50 0.08 Gross Alpha(pCUL 0.88 056 13-Feb-02 15 005 M- Y . Gross BatafpCUL) 5.31 2A2 16-AJ2 50 0.11 tB.-z '--?u==- GrossAlpha(pCUL) 1 0.673 16-4102 15 0.07 V___ ___- .. NI-83(Cilt) 4.14 2.95 30-Aug-02 r.T. i -1 50 0.08 0.08 Gross BtalpCUL) 7.39 2.56 8-Nov-02 50 0185 Gross betalpCiL) 5.01 2A9 204an-03 50 010 Gross BelalpCUL) 3.24 2.66 2-Mayi03 50 0.06 6 .'4t1; W  ; Gross BetalpCUL) 5.1 Z2 23-Jun.03 50 0.10 PX .- 'r w 4 4. j. t . Groass BetalpCL) 4.12 2.62 22-NOV-03 50 0.08 _ Groass BetepCVL) 5.52 2.62 27-Jan-04 50 0.11 Total U JIL 0.037 0.00978 2-Feb-04 30 0°00 ___M Gross Beda(pCIL) 4.95 2.37 22-Apr-4 50 0.10 S! _ GrossAlphaPCL) 0.731 0.678 22 -04 1S 0.05 -- 51MO MW-112S Gross e2a(pC'JL) a1 .51 6-Nov-02 50 0.07 Gross Ba( pCVLI 2.62 2.5 22-Nov-03 50 0.05 Sr-0(pCi/L) 5.49 0.634 18an-04 tY 8 09 0.69 Total U ug) 0.0155 0.0078 30-an04 30 0.00 n MYY113s Gross Beta(pC1L) 31.4 3.63 6-Nov-2 50 0.63-Gross AlphDCIL) 295 1.87 6-Nov-02 15 0.20 Pi' t N nEW Gross BataepClIL) 30.3 3.4 20-Jan-03 50 0.61 r5___ t  ! if GrossAlohafpCL) 1.82 1.02 21Jan-3 15 012 'r Gross Beta~pCUL) 23.4 2.81 7-May03 50 0.47 , , b Gross BetalpCULI 16.8 2.9 234un-3 50 0.34 Ii ._Ng-V4 i2 _t is 6, f1's Gross Beta(pCUL) 23.4 3.12 22-Nov-03 50 0.47, Sr-900(CUL) 0.579 0.582 23-Nov-03 8B; 0.07 0.07 GrossBota(pCUL) 22.7 2.94 12-Jan-04 50 0.45 Sr-900pCUL) 0.838 0.719 1648an.04 &  ; -- A 0.19 0.10 Total UlugL) 0.0716 0.00978 19-Jan-04 30 0.00 n1 - i- -i i -2x Gross BapCUL) 18.3 2.73 22pr.04 50 0.33 C Gross Bdsa(pCUL) 8.3 2.54 22-Ju04 50 0.17 M:* 4t __ __ Gross Bata(PCUL) 17.5 2.3 19-OctD-04 50 035 F.. - MW-1173 (irss tetalpCUL) 8.36 3.00 15-Nov- 50 Gros A1phalOCL) IAP 1"26 Nov-02 IS Grass BataipCUL) 7.66 2.86 20DJan-03 50 Sr-90(PCyU 128 0.812 24-Jan-03 E.2 0.156 Gross 8etalpC/L) 8.13 3.05 7-May-03 0.16 1,:.MIEU . i-$Wr- .; ' r. & Gross BalispCVL) 11.66 2.1 23-Jun-03 50 0.23 GrossAlotoa(pCUI.) 3.8 Z9 23-Jn-03 15 0.25 - Grass BetalpC/L) . 9.49 3.97 22-Nov-03 50 0.19 r;. Sr-9OlpCl/LI 1A2 0.57 23-o03 8a 0.18 018 Sr-9OlpCVL) 0.765 0.512 18an-04 a8 0.10 0.10 Gross BetaC pClL 9.85 3.98 20Jan-04 50 0.19 E1.'; Gross Ueta(pCULI 5.41 3.23 22A404 50 0.11 _ Gross Betal(pCUL 7.28 2.3 29-Jul-04 60 0.15 'I )-Pt:!- Gross Bela(pCUL) 6.91 2.17 14-Oct-04 50 0.14 ,4p I of2

Table A-2 Peninsula Evaluation Summary of Historical Groundwater Detections Comparod to MCLs Connecttcut Yankee Haddam Neck Plant Haddam Neck. CT Fraction Isotope Equivalent f Non. Equivalent Fraction of Concentnraton 1t Net Analysts Non-Dose Dose Concentntlon' Equlvalent Sum-of-Well ID NuclIde)Anidyte (unlt) ConcentrstIon Actual MDC Date MCL MCL (pCIJL) Concentration Fractions MW.2 Gross Beta(pCUL) 2.75 2.7 20-Jan-03 50 0GB J-Pu-241(PCL) 11.2 6.34 31-Jen.03 ^i-4 300 0.04 0.04 Gross BetalpctL) 4.43 2.46 2-4uP04 50 0.09 N H-3(pCVL) 439 300 7-Oet-04 20000 0.02 0.02 Gross Beat(pCfl. 3.47 2.27 14-Od-04 S0 0.07 rE- k SupptyWell Sr-90(pCULL) 1.02 0.45 30-Jan-02 k: 4- Nj E 0.13 0.13 Notes:

1) Isotope EqutvalentConcentration

• concentraUon ofan Indlsidual tsotope. whichwould rmsuInan MCLexeredance 201t2

PC Wc. k. A.UMc-A.~

             ~ ~~ ~ ~~~~~~~~IG I"AI MDC C- I     Dt.TM4AMS 1 045~114xhTC~~c~DTA~,

I

                                                         ~4.JMJ ~A ~PM
  ~H2MHILL

Table A-3 Radlonuclides Detected In Discharge Canal Sediment Samples FSS Survey Unit 9106 Sediment Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Location ID 9106-0011-1618D-01 Radionuclide' Result 2-SIgma TPU Ain-241 (PCilg) 0.0692 (PCi/g) 0.0784 J(pCI/g) MDC 10.0626 Date 5/5/2004 9106-SD-1621-C-00 C-14 0.23 0.0928 7 0.149 7/21/2004 9106-SD-1619-C-00 C-14 0.232 0.0959 j 0.154 7121/2004 9106-0002-1609C-01 C-14 0.242 0.11 l 0.178 6/30/2004 9106-SD-1621-C-01 C-14 0.253 0.103 l 0.165 7/21/2004 9106-0001-1604C-01 C-14 0.266 0.108 0.172 613012004 9106-0004-1605D-01 C-14. 0.272 0.0963 0.156 5/512004 9106-0011-16180-01 Co-60 0.0471 0.026 0.0193 5/5/2004 9106-0002-161OC-05 Co-60 0.0581 0.0372 0.0367 6/29/2004 9106-0002-1608C-01 Co-60 0.0625 0.0312 0.0323 6/30/2004 9106-0003-1611C-01 Co-60 0.0741 0.0429 0.0423 6/29/2004 9106-0006-16090-02 Co-60 0.0914 0.0476 0.0396 5/512004 9106-0001 -1602C-09 Co-60 0.092 0.0355 0.0341 6130/2004 9106-0007-16120-01 Co-60 0.102 0.0522 0.0399 5/6/2004 9106-0003-1612C-01 Co-60 0.129 0.0392 0.0371 l 6/29/2004 9106-0001-1604C-01 Co-60 0.151 0.0323 0.0273 l 6/30/2004 9106-0007-1611D-02 Co-60 0.155 0.0635 0.064 l 516/2004 9106-SD-1620-C-01 Co-60 0.204 0.0536 0.0344 j 7/21/2004 9106-0009-1615D-01 Co-60 0.224 0.0554 0.0369 j 5/5/2004 9106-0011-1617D-02 l Co-60 0.247 0.0359 0.0251 5/512004 9106-0003-16020-02 Co-60 0.286 0.0549 0.0441 5/5/2004 9106-0011-16170-01 l Co-60 0.345 j 0.0814 0.0656 5/5/2004 9106-SD-1620-C-00 l Co-60 0.35 0.0425 0.0254 7121t2004 9106-0003-1613C-01 Co-60 0.365 0.0622 0.0423 6129/2004 9106-SD-1619-C-01 Co-60 0.433 0.0676 0.0324 7121/2004 9106-0007-1611D-01 Co-60 0.446 0.084 0.0559 516/2004 9106-0006-1609D-01 Co-60 0.455 0.0846 0.0452 5/5/2004 9106-0006-1608D-01 Co-60 0.468 0.0604 0.0324 5/5/2004 9106-0009-16140-01 Co-60 0.567 0.0852 0.0458 5/6/2004 9106-0006-1608D-02 CO-60 0.614 0.0753 0.0416 51512004 9106-SD-1618-C-00 Co-60 0.723 0.0796 0.035 7/21/2004 9106-SD-1619-C-00 Co-60 0.902 0.107 0.0365 7/21/2004 9106-0001-1605C-01 Co-SO 1 0.0718 0.0329 7/112004 9106-0001-1602C-01 Co-60 1.02 0.0969 0.0322 6130/2004 9106-0001-1606C-01 CO-60 1.04 0.0963 0.0355 7/1/2004 9106-0011-1616D-02 Co-60 1.05 0.102 0.0375 515/2004 9106-0002-161OC-01 Co-60 1.2 0.0946 0.0416 6/29/2004 9106-0002-1609C-01 Co-60 1.38 0.127 0.0449 6/30/2004 9106-0003-1613C-04 Co-60 1.49 0.136 0.0396 6/29/2004 9106-0004-1605D-02 Co-60 1.85 l 0.14 0.0361 5/5/2004 9106-SD-1621-C-00 Co-60 2.04 0:158 0.0341 7/21/2004 9106-SD-1621-C-01 Co-60 2.35 0.196 0.0427 7/21/2004 9106-0004-16050-01 Co-60 3.04 0.251 0.0689 5/5/2004 9106-0003-1611C-05 Cs-137 0.0197 0.0144 0.0155 6/29/2004 9106-0003-1602D-01 Cs137 0.033 0.0147 10.0216 5/512004 9106-0003-16030-01 Cs-137 0.0346 0.0192 l0.0222 5/4/2004 9106-0003-1612C-04 Cs-137 0.0379 0.018 l 0.0201 6129/2004 9106-0009-1614D-02 Cs-137 0.0561 0.0293 0.0322 5/6/2004 I of 3

Table A-3 Radionuclides Detected In Discharge Canal Sediment Samples FSS Survey Unit 9106 Sediment Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Location ID IRadionuclide Result 2-Sigma TPU MDC ____ ____ ____ __ I.(pC ilg) P ' ) Date 9106-0001-1607C-01 Cs-137 0.0612 0.0368 0.0473 7/112004 9106-0011-1618D-01 Cs-137 0.0647 0.0212 0.0223 515/2004 9106-0004-16040-01 Cs-137 0.0659 0.0413 0.0335 51412004 9106-0011-1616D-01 Cs-137 0.0728 0.0308 0.0286 5/6/2004 9106-0001-1602C-09 Cs-137 0.0783 0.0287 0.0306 6/30/2004 9106-0009-1615D-01 Cs-137 0.0893 0.0399 0.0401 5/5/2004 9106-0007-16120-01 Cs-137 0.104 0.0517 0.0431 516/2004 9106-0001-1604C-01 Cs-137 0.109 0.0269 0.0202 6/30/2004 9106-0006-1609D-02 Cs-137 0.121 0.0426 0.0389 5/5/2004 9106-0011-1617D-02 Cs-137 0.123 0.0315 0.0231 515)2004 9106-0003-1602D-02 Cs-137 0.125 0.0361 0.0406 515/2004 9106SSD-1619-C-01 Cs-137 0.129 0.0464 l0.0349 7/2112004 9106-0007-1611D-02 Cs-137 0.13 0.0698 0.0612 516/2004 9106-SD-1620-C-01 Cs-137 0.172 0.0391 0.0324 7/21/2004 9106-0003-1611C-01 Cs-137 0.203 0.0579 0.043 6/29/2004 9106-0006-1608D-01 Cs-137 0.207 0.0368 0.0289 5/512004 9106-0006-1608D-02 Cs-137 0.212 0.0553 0.0393 5/512004 9106-0002-1610C-05 Cs-137 0.222 0.0565 0.0412 6/29/2004 9106-0006-1609D-01 Cs-137 0.222 0.0497 0.0331 51512004 9106-0007-1612D-02 Cs-137 0.223 0.0402 0.039 5/6/2004 9106-0003-1612C-01 Cs-137 0.229 0.0408 0.03 6/29/2004 9106-0011-1617D-01 Cs-137 0.237 0.0777 0.0618. 5/512004 9106-0003-1613C-01 Cs-137 0.24 0.0519 0.0393 6/29/2004 9106-SD-1619-C-00 Cs-137 0.247 0.0456 0.0358 7121/2004 9106-SD-1618-C-00 Cs-137 0.259 0.048 0.0313 7/21/2004 9106-0007-16110D-01 Cs-137 0.313 0.0733 0.056 5/6/2004 9106-SD-1620-C-00 Cs-137 0.316 0.0381 0.027 7/21/2004 9106-0011-1616D-02 Cs-137 0.361 0.0604 0.0427 5/5/2004 9106-0001-1602C-01 Cs-137 0.367 0.0491 0.0363 6/30/2004 9106-SD-1621-C-OO Cs-137 0.394 0.0603 0.0404 7/21/2004 9106-0001-1605C-01 Cs-137 0.41 0.0458 0.0364 7/1/2004 9106-0003-1613C-04 Cs-137 0.444 0.052 0.0332 6/29/2004 9106-0001-1606C-01 Cs-137 0.464 0.062 0.0366 7/1/2004 9106-0009-1614D-01 Cs-137 0.475 0.0697 0.0442 5/6/2004 9106-0004-1605D-02 Cs-137 0.482 0.0728 0.0407 5/5/2004 9106-SD-1621-C-01 Cs-137 l 0.561 0.0861 0.0475 7/21/2004 9106-0004-16050-01 Cs-1 37 0.592 0.132 0.0731 5/5/2004 9106-0002-1610C-01 Cs-137 1.28 0.0885 0.0467 6/2912004 9106-0002-1609C-01 Cs-137 1.32 0.147 0.0402 6/30/2004 9106-0003-1612C-01 Fe-55 46.9 32.1 31 6/29/2004 9106-0002-1609C-01 Fe-55 49.9 31.3 31.1 613012004 9106-0011-16180-01 NI-63 24.2 11.4 18.4 5/5/2004 9106-011-1618D-02 Ni-63 25.9 15.5 25.4 5/5/2004 9106-0009-1615D-02 Ni-63 34.7 16 25.8 5/6/2004 9106-0003-1612C-01 Pu-239 0.0214 0.021 0.0145 6/29/2004 9106-0004-16050-01 Pu-239 0.593 0.254 0.195 5/5/2004 9106-0006-16070-02 Sr-90 10.0202 0.0102 0.0185 5/5/2004 9106-0009-16130-02 Sr-go 10.0246 0.0108 0.0172 5/5/2004 2 of3

Table A-3 Radionuclides Detected In Discharge Canal Sediment Samples FSS Survey Unit 9106 Sediment Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Location ID Radionuclide Result 2-SIgma TPU MDC Date (pCl~g) (pCI/g) (pCI/g) 9106-SD-1618-C-01 Sr-90 0.025 0.0118 0.0191 7121/2004 9106-0007-1612D-02 Sr-90 0.02591 0.0102 0.0161 516/2004 9106-0009-1613D-01 Sr-90 0.02951 0.01259 0.0199 515/2004 9106-0011-1617D-02 Sr-90 0.03021 0.00995 1 0.0154 15/512004 9106-0007-1611D-01 Sr-90 0.03071 0.0105 10.01631 5/6/2004 9106-0006-1609D-01 Sr-90 0.0308 0.0104 l0.0161 5/5/2004 9106-0009-1614D-02 Sr-90 _0.0311 0.0108 l 0.0169 5/6/2004 9106-0003-1602D-02 Sr-90 0.0315 0.0124 0.0213 5/5/2004 9106-SD-1620-C-00 Sr-90 0.0343 0.0116 0.0165 7/21/2004 9106-0009-1614D-01 Sr-90 0.0346 0.0106 0.0164 5/6/2004 9106-0011-16170-01 Sr-90 0.0358 0.0118 0.0183 5/5/2004 9106-SD-1618-C-00 Sr-90 0.0362 0.00997 0.0121 712112004 9106-0003-1603D-02 Sr-90 0.0377 0.0131 0.0208 5/4/2004 9106-SD-1621-C-00 Sr-90 0.0384 0.0114 0.0151 7/2112004 9106-0007-1611D-02 Sr-90 0.0402 0.0108 0.0164 5/6/2004 9106-0004-1606D-01 Sr-90 0.0403 0.0134 0.0221 5/5/2004 9106-0007-1610D-02 Sr-90 0.0431 0.0107 0.0161 5/6/2004 9106-0006-1608D-02 Sr-90 0.0479 0.012 0.0182 5/5/2004 9106-0007-1612D-01 Sr-90 0.0525 0.0124 0.0184 5/6/2004 9106-SD-1620-C-01 Sr-90 0.0544 0.0122 0.0135 7/21/2004 9106-SD-1619-C-01 Sr-go 0.0635 0.0126 0.00983 7/2112004 9106-0004-1604D-01 Sr-90 0.0652 0.0181 0.0281 5/4/2004 9106-SD-1621-G-01 Sr-go 0.06671 0.0136 0.0148 7/21/2004 9106-0006-1609D-02 Sr-90 0.06811 0.0126 0.0181 5/5/2004 9106-0004-1605D-01 Sr-go 0.0702 0.0192 0.0295 5/5/2004 9106-0006-1608D-01 Sr-90 0.0716 0.0156 0.022 5/5/2004 9106-0004-1604D-02 Sr-90 0.0756 0.0158 0.0203 5/5/2004 9106-0004-1606D-02 Sr-90 0.141 0.0203  ! 0.0198 5/5/2004 9106-0004-1605D-01 Tc-99 0.449 0.221 1 0.359 5/5/2004 Notes: pCilg = picocuries per gram TPU = total propagated uncertainty MDC = minimum detectable concentration 3 of 3

Table A-4 Radlonuclides Detected In Discharge Canal Sediment Samples Compared to Soil Screening Concentrations FSS Survey Unit 9106 Peninsula Evaluation Haddam Neck Plant, Haddam Neck, CT Nm rof Minimum ExcidnSilu Maximum Maximum xces Average Average Radionucide RadinucideNumbr o Cocenratin Detections Conentmtion Ecees screening Sil Cncetraion Concentration Soil Screening Concentration Concentration? (pCilg) Exceeds ScreeningSoil[ (pCUg) Low High (pCitg) Low High l Low High Am-241 1 0.07 -.jNot,Establlshe~d 0.07 . .:,Not Estabilshed;:.. 0.07 :Not Established Co-60 71 0.01 no no 9 yes 0.5 yes I no Pu-241 1 6.60 Ndt Estabilshedd? 6.6  :`-Not Establlshed.; 6.6 *Not!Established Sr-90 43 0.02 no no 0.26 yes no 0.06 no T no Tc-99 1 0.45 $,Not Estabiished 0.45 .,,'Not Establishedt 0.45 .-Not Established C-14 10 0.02 .'NUt Estabiished 0.27 z.Not Estabilshedr'- 0.17 Not Estabiished Pu-239 2 0.02 -.z4Not,EstabIlsI ,d5 0.59 -.;Not Estabblshed,<-. 0.31 INot Established NI-63 3 0.01 ,Not.EstabislhedO 34.7 *..-::NdtEstablishedl.. 16.98 :Not Estabilshed Fe-55 2 0.03 no no 49.9 no no 32.28 no no Cs-137 64 0.01 no no 13.6 yes ( no 0.53 no no I of I

IC.W 1 -N2 A IHS~JAD co~lc1~AD4 *INAMWMT qMICABEC4fRfa 6 H~~cISIA~cE CMALSW4TST~h~IWDawlEQRAI CH2MHI,.

Radionucildes Detected In Soil Samples Compared to Soil Screening Concentrations FSS Survey Unit 9530-01 Soil Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Estimated Soil Estimated Soil Estimated Estimated Result MDC Screening Result exceeds low Screening Result exceeds Equilibrium Equlibrium Locatton iD Radonucide ( ) Date Concentration - soil screening Concentration - high soil screening Groundwater Groundwater (Pctug) (pctlg) LM1) concentration? High (2 concentration? concentration, concentration, (pClg) (pCl/g) Low Kd 3) High Kd (4) (pCIL) (pCIIL) 9530-01-001C Cs-137 0.221 0.0613 8/112004 4.60 No 29.80 No 9.61 1.48 9530-01-002C Cs-137 0.394 0.015 811812004 4.60 No 29.80 No 17.13 2.64 953D-01-003C Cs-137 0.374 0.0484 8/118/2004 4.60 No 29.80 No 16.26 2.51 9530-01-004C Cs-137 0.0739 0.0475 8/1812004 4.60 No 29.80 No 3.21 0.50 9530-01-005C Cs-i 37 0.116 0.044 88112004 4.60 No 29.80 No 5.04 0.78 9530-01-006C Cs-137 0.098 0.0668 8/18/2004 4.60 No 29.80 No 4.26 0.66 9530-01-007C Cs-137 0.167 0.0264 8/182004 4.60 No 29.80 No 7.26 1.12 9530-01-007C Tc-99 0.455 0.327 8/18/2004 Not Determined  :....

                                                                                                *. *-. NotDetermrined        *             -.!'    *      *.. ..

9530-01-008C Cs-137 0.105 0.0382 8/18/2004 4.60 No 29.80 No 4.57 0.70 9530-01-009C Cs-137 0.126 0.048 8/18/2004 4.60 No 29.80 No 5.48 0.85 9530-01-010C Cs-137 OA68 0.056 811812004 4.60 No 29.80 No 20.35 3.14 9530-01-012C Cs-137 0.276 0.0446 8/18/2004 4.60 No 29.80 No 12.00 1.85 9530-01-014C Cs-137 0.183 0.0554 8118/2004 4.60 No 29.80 No 7.96 1.23 9530-01-015C Cs-137 0.166 0.047 8/18/2004 -4.60 No 29.80 No 7.22 1.11 9530-01-016C Cs-137 0.09 0.0469 8119/2004 4.60 No 29.80 No 3.91 0.60 9530-01-017C Cs-137 0.256 0.0454 811912004 4.60 No 29.80 No 11.13 1.72 9530-01-019C Cs-137 0.228 0.0505 8/19/2004 4.60 No 29.80 No 9.91 1.53 9530-01-020C Cs-137 0.2 0.0472 8/1912004 4.60 No 29.80 No 8.70 1.34 9530-01-021C Cs-137 0.228 0.0648 8/1912004 4.60 No 29.80 No 9.91 1.53 9530-01-022C C-14 0.626 0.407 8/19/2004 Not Determined  ; Not Determined * . .. - . 9530-01-022C Cs-i 37 0.0973 0.0572 6/19/2004 4.60 No 29.80 No 4.23 0.65 9530-01-024C Cs-137 0.176 0.0484 8119/2004 4.60 No 29.80 No 7.65 1.18 9530-01-025C Cs-137 0.135 0.0533 8/19/2004 4.60 No 29.80 No 5.87 0.91 9530-01-026C Cs-137 0.124 0.0459 811912004 4.60 No 29.80 No 5.39 0.83 9530-01-027C Cs-i 37 0.0902 0.053 8/1912004 4.60 No 29.80 No 3.92 0.61 9530-01-028C Cs-137 0.125 0.0513 8/19/004 4.60 No 29.80 No 5.43 0.84 9530-01-029C Cs-137 0.191 0.0391 8119/2004 4.60 No 29.80 No 8.30 1.28 9530-01-030C Cs-134 0.0639 0.0618 8/19/2004 4.60 No 29.80 No 2.78 0.43 9530-01-030C Cs-i 37 0.0645 0.0464 8/19/2004 4.60 No 29.80 No 2.60 0.43 IPVULLSI3-f 1pL.ULJI /.Zya ] .f. Avg Cs-i34 pCUL/ 2.78 0.43 Notes: 1)Thls value was calculaled as Kd Vkb nucilde MCL equivalent concentration. The soil type with the lowest Ki value was used In this case. 2)This value was calculated as Kd value

• nucilde MCL equivalent concentration. The soil type with the highest Kd value was used In this case.

3)This value was calculated as measured soil concentration/Kd. The lowest Kd was used. 4)This value was calculated as t pCUL = picocurles per liter pCVg = pirocuries per gram TPU = total propagated uncertainty MDC = minimum delectable concentration 1of I

N PEIXt61A EVALWATION A roCE9RMTIN OFCOIITALI NMhTSOFCONCERNWsOL A. _ PENNStlANAL REY UNIT SlTATUS 9SW,1VADDAM ECKPLW A. C --

Radionuclides Detected In Soil Samples Compared to Soil Screening Concentrations FSS Survey Unit 9530-02 Soil Samples Peninsula Evaluation Haddam Nock Plant, Haddam Neck CT Estimated Sol Estimated Soil Estimated Estimated Result MDC Screening Result exceeds low Screening Result exceeds Equilibrium Equilibrium Locaton ID Radionuclide RDate Concentration - soil screening Concentration- high soil screening Groundwater Groundwater (pCWg) (pCMg) Low t i) concentration? High 12 concentration? concentration, concentration, (pCI/g) (pCI/g) Low Kd (3) High Kdt4 t (pCUL) (pCUL) 9530-02-016C Cs-137 0.303 0.0521 08118/04 4.60 No 29.80 No 13.17 2.03 9530-02-017C Cs-137 0.104 0.0422 08/18/04 4.60 No 29.80 No 4.52 0.70 9530-02-017-COI C-14 0.238 0.171 09121/04 NotDetermined : NotDetermIned . '.,.. *;a4 .';*. : :. . .. f:.. 9530-02-018C Cs-137 0.112 0.0411 08/18104 4.60 No 29.80 No 4.87 0.75 9530-02-019C Cs-137 0.137 0.0529 08118/04 4.60 No 29.80 No 5.96 0.92 9530-02-019-COl Cs-137 0.0902 0.0346 09/21104 4.60 No 29.80 No 3.92 0.61 9530-02-021C Cs-137 0.0694 0.057 08/18104 4.60 No 29.80 No 3.02 0.47 953D-02-023C Cs-137 0.147 0.0498 08118104 4.60 No 29.80 No 6.39 0.99 9530-02-024C Cs-1 37 0.0896 0.0362 08/18104 4.60 No 29.80 No 3.90 0.60 9530.02-024-C0l Cs-137 0.0633 0.0308 09121/04 4.60 No 29.80 No 2.75 0.42 953G.02-025C Cs-137 0.13 0.0367 08/18/04 4.60 No 29.80 No 5.65 0.87 9530-02-026C Cs-137 0.142 0.0403 08/18/04 4.60 No 29.80 No 6.17 0.95 9530,02-026-COI Cs-137 0.0421 0.0384 09120/04 4.60 No 29.80 No 1.83 0.28 9530-02-027C Cs-137 0.0848 0.0356 08/18/04 4.60 No 29.80 No 3.69 0.57 9530-02-028C Cs-137 0.12 0.046 08/18/04 4.60 No 29.80 No 5.22 0.81 9530-02-029-C0l Cs-137 0.0437 0.0252 09120/04 4.60 No 29.80 No 1.90 0.29 9530-02-030C Cs-1 37 0.0963 0.0224 08/18/04 4.60 No 29.80 No 4.19 0.65 lAv9 Cs-137 (pCUL)l 4.99 l 0.65 Notes: 1)This value was calculated as Kdvalue Son Screening Concentration. The soil type with the lowest Kd value was used In this case. 2)This value was calculated as Kd value

• Sol Screening Concentration. The soil type with the highest Kd value was used In this case.

3)This value was calculated as measured soil concentration/Kd. The lowest Kd was used.

4) This value was calculated as measured soil concentratfonrKd. The highest Kd was used.

pCIg = plcocurles per gram pCl/L = picocurles per Ilter TPU =total propagated uncertainty MDC = minimum detectable concentration 1 of 1

FOUREA4 N 'R. AEVAJLUIC A. _ arLtW OFCWTAMNfA~ OFCMCM HSO EXED CCNCc*OfMTD MINMJM tREtCt4SEC04D~tATCNa AWMMNEOt CKT GH2MHILL ' a - lAIC== u mT

Radlonucildes Detected In Soil Samples Compared to Soil Screening Concentrations FSS Survey Unit 9530-03 Soil Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Estimated Soil Estimated Sall isimated Equsilbrium Res CScreentngResult exceeds low Screening Result exceeds Estimated Eroundwater Locatton ID Radionucide (pCI/g) (pCIg) Date Concentration - soil screening Concentration - high soil screening Groundwater concentration. owM concentration? HTgh(2) concentration? concentration, High Kd "' (pCIlg) (pCVg) Low Kd "1(pCiIL) (pCVL) 9530-03-001C Cs-137 027 0.0549 8/18/2004 4.6 No 29.8 No 11.74 1.81 9530-03-002C Cs-137 0.388 0.0416 B/11 2004 4.6 No 29.8 No 16.87 2.60 9530-03403C Cs-137 0.205 0.0443 8/1712004 4.6 No 29.8 No 8.91 1.38 9530-03-004C Cs-137 0.14 0.063 8/1812004 4.6 No 29.8 No 6.09 0.94 9530-03-005C Cs-137 0.126 0.0238 8/18/2004 4.6 No 29.8 No 5.48 O.B5 9530-03-006C Cs-137 0.125 0.0329 8/1712004 4.6 No 29.8 No 5.43 0.84 9530-03-006C Mn-54 0.0365 0.0326 8/1712004 Not Determined  :. Not Determined *.  :  ; -;; - .;  ;. . - 9530-03-006C Sr-90 0.0114 0.0113 8/17/2004 0.08 No 0.352 No 1.14 028 9530-03-007C Cs-137 0.14 0.0401 8/1712004 4.6 No 29.8 No 6.09 0.94 9530-03-OOBC Cs-137 0.125 0.0261 8/17/2004 4.6 No 29.8 No 5.43 0.84 9530-03-008-COI Cs-137 0.133 0.0234 912112004 4.6 No 29.8 No 5.78 0.89 9530-03-009C Cs-137 0.0901 0.0276 8/17/2004 4.6 No 29.8 No 3.92 0.60 9530-03-011OC Cs-137 0.249 0.0425 8/1712W04 4.6 No 29.8 No 10.83 1.67 9530-03-011 C Cs-137 0.191 0.0351 8/17/2004 4.6 No 29.8 No 8.30 1.28 9530-03-011-CO1 C-14 0.223 0.155 9/2112004 Not Determined  ;;: .

                                                                                          *,        Not Determined .           *                      --- .'. -- .-

9530-03-011-COl Fe-55 46.9 31.3 9/2112004 320 No 2400 No 293.13 39.08 9530-03-012C Cs-137 0.169 0.0429 8/1712004 4.6 No 29.8 No 7.35 1.13 953M03-013C Cs-1 37 0.236 0.0433 8/1 B/2004 4.6 No 29.8 No 10.26 1.58 9530-03-014C Cs-137 0.304 0.0395 8/17/2004 4.6 No 29.8 No 13.22 2.04 9530-03-015C Cs-137 0.213 0.0296 8l1712004 4.6 No 29.8 No 9.26 1.43 953-03-01 5C Fe-55 60.7 49.9 8/17/2004 320 No 2400 No 379.38 50.58 1AVU UhS-101fULpUL11 M~UD . I1+ Avg Sr-90 (CI/iL. 1.14 1 0.26 Avg Fe-55 (pCVL) 335.25 44.B3 Notes:

1) This value was calculated as Kd value' MCL Equivalent Concentration. The soil type with the lowest K.d value was used In this case.

2) This value was calculated as Kd value

• MCL Equivalent Concentration. The son type with the highest Kd value was used In this case.

3) This value was calculated as measured soil concentrationfKd. The lowest Kd was used.

4) This value was calculated as i pCiL = picocuries per liter pCig = picocuries per gram TPU = total propagated uncertainty I of 1

PFMSAAEVAMATD A 0 m WIRAEIUN CF WAMNWTS OF CBRN Ed IN PQMWGUA U GI IiOL) FINASTATMWMtYwMTg DEThCT=AEWMCRATO rfl WAwIXKcrJJ4 CH2MHILL

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Radionuclides Detected In Soil Samples Compared to So!l Screening Concentrations FSS Survey Unit 9530-04 Soil Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Result MDC IEstimated Screening Sail Result exceeds Estimated Soil ScreenIng Result exceeds EstimatedEqiiru EsiaeEquilibriumGrudae LocatonlD Nucide l Date Concentration - Low low soil screening Concentration - high soil screening Groundwater concentration (pCl~g) (polvg) (I) concentration? HIgh(2) concentration? ocnrto ihK " I _ __ I__ (pClg) (pClg) 1Low Kd 131(pCl/L) (pCl/L) 9530-04-001C Cs-i 37 0.193 0.0375 8123/2004 4.6 No 29.8 No 8.39 1.30 9530-04-003C Cs- 137 0.123 0.0341 8/23/2004 4.6 No 29.8 No 5.35 0.83 9530-04-004C Cs-137 0.219 0.0481 8/2312004 4.6 No 29.8 No 9.52 1.47 9530-04-005C Cs-1 37 0.0915 0.0385 823/2004 4.6 No 29.8 No 3.98 0.61 9530-04-006C Cs-137 0.172 0.0364 8/2412004 4.6 No 29.8 No 7.48 1.15 9530-04-007C Cs-137 0.188 0.0457 812412004 4.6 No 29.8 No 8.17 1.26 9530-04-009C Cs-137 0.106 0.0312 8/24/2004 4.6 No 29.8 No 4.61 0.71 9530-04-010C Cs-1 37 0.375 0.0365 8124/2004 4.6 No 29.8 No 16.30 2.52 9530-04-O0IC Cs-137 0.136 0.0313 8124/2004 4.6 No 29.8 No 5.91 0.91 9530-04-012C Cs-137 0.0798 0.035 8/24/2004 4.6 No 29.8 No 3.47 0.54 9530-04-012-COI Cs-137 0.0753 0.0294 9/15/2004 4.6 No 29.8 No 3.27 0.51 9530-04-013C Cs-137 0.0891 0.0225 8)424004 4.6 No 29.8 No 3.87 0.60 9530-04-013C PL-239 0.0712 0.0483 8/24/2004 NotDetermined = Lx3., k.- Not Determinmend .;-.. e  ;.;  ! . . -. 9530-04-013-CO0 Cs-137 0.0797 0.0437 911512004 4.6 No 29.8 No 3.47 0.53 9530-04-014C Cs-137 0.0904 0.0545 8/24/2004 4.6 No 29.8 No 3.93 0.61 9530-04-014-Cal Cs-137 0.0564 0.0434 911512004 4.6 No 29.8 No 2.45 0.38 9530-04-015C Cs-137 0.0986 0.0249 8124/2004 4.6 No 29.8 No 4.29 0.66 9530-04-015-C0l Cs-137 0.0734 0.025 9115/2004 4.6 No 29.8 No 3.19 0.49 9530-04-016C Cs-137 0.153 0.0458 8/24/2004 4.6 No 29.8 No 6.65 1.03 9530-04-016-COl Cs-137 0.0752 0.0306 9/15/2004 4.6 No 29.8 No 3.27 0.50 9530-04-017C Cs-137 0.192 0.038 8)24/2004 4.6 No 29.8 No 8.35 1.29 9530-04-018C Cs-137 1.13 0.0443 8)24/2004 4.6 No 29.8 No 49.13 7.58 9530-04-01BC Sr-90 0.0502 0.0209 8/24/2004 0.08 No 0.352 No 5.02 1.14 9530-04-018-C01 C-14 0.255 0.169 9)15/2004 Not Determined - NotDetermined :l . -. .... 95304-019C Cs-137 0.0797 0.0363 8/24/2004 4.6 No 29.8 No 3.47 0.53 9530-04020C Cs-137 0.169 - 0.048 8/24/2004 4.6 No 29.8 No 7.35 1.13 Ava Gs-137 (nCULI 5.14 0.93 Avg Sr-9oI Ci!fil) 502 1 1.14 Notes: 1)This value was calculated as Kdvalue I MCL Equivalent Concentration. The soil type with the lowest Ki value was used In this case. 2)This value was calculated as Kd value I MCL Equivalent Concentration. The soil type with the highest Kd value was used Inthis case. 3)This value was calculated as measured soil concentratlon/d. The lowest Kd was used. 4)This value was calculated; pClIL = picocurles per liter pC~g = picocuries per gram TPU = total propagated uncertainty MDC = minimum delectable concentration 1 of 1

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Radionucilde Detections and Groundwater Protection Soil Screening Criteria Concentrations FSS Survey Unit 9530.05 Soil Samples Peninsula Evaluation Haddam Neck Plant, Haddam Neck CT Estimated Soil Estimated Soil Estimated Equmate Result MDC Screening Result exceeds low ScreenIng Result exceeds Equilibrium Groundwater Location ID Radlonuclide Date Concentration - soil screening Concentration - high soll screening Groundwater concentration, (pCifg) (pC/g) Low~l) concentration? High 2( concentration? concentration, High Kd I4) (pCIlg) (pCl/g) I _I Low Kd PI (pCI/L) (pCi/L) 9530-05-002C Co-60 1.09 0.0537 7120/2004 0.2 Yes 22 No 545.00 4.95 9530-05-002C Cs-137 1.62 0.05565 7/20/2004 4.6 No 29.8 No 70.43 10.87 9530-05-002C Sr-90 0.0445 0.0285 7/2012004 0.08 No 0.352 No 4.45 1.01 9530-05-003C Co-60 1.61 0.0532 7120/2004 0.2 Yes 22 No 805.00 7.32 9530-05-003C Cs-137 1.39 0.0514 7/20/2004 4.6 No 29.8 No 60.43 9.33 953D-05-003C Tc-99 0.518 0.408 7/2012004 NotDetermined Not__________ _Notet 9530-05-004C Co-60 2.3 0.0631 7/20/2004 0.2 Yes 22 No 1150.00 10.45 9530-05-004C Cs-137 1.66 0.0758 7/20/2004 4.6 No 29.8 No 72.17 11.14 9530-05-004C Sr-90 0.0808 0.0303 7/20/2004 0.08 Yes 0.352 No 8.08 1.84 9530-05-005C C-14 0.165 0.165 7/21/2004 Not Determined Z.Q . Not DetermIned  :.......:. . - **. . 9530-05-005C Co-60 0.759 0.0618 7/21/2004 0.2 Yes 22 No 379.50 3.45 9530-05-005C Cs-137 1.36 0.0539 712112004 4.6 No 29.8 No 59.13 9.13 9530-05-005C Sr-90 0.0491 0.029 7/21/2004 0.08 No 0.352 No 4.9 1.1 9530-05-006C Co-60 0.392 0.0463 7121/2004 0.2 Yes 22 No 196.0 1.8 9530-05-008C Cs-137 0.557 0.0419 7/21/2004 4.6 No 29.8 No 24.2 3.7 9530-05-007C Co-60 0.139 0.0386 7/20/2004 0.2 No 22 No 69.5 0.6 9530-05-007C Cs-1 37 0.716 0.0465 7/20/2004 4.6 No 29.8 No 31.1 4.8 9530-05-008C Co-60 0.227 0.049 7/21/2004 0.2 Yes 22 No 113.5 1.0 9530-05-008C Cs-137 0.961 0.0417 7/21/2004 4.6 No 29.8 No 41.8 6.4 9530-05-009C Co-60 0.0955 0.05 7121/2004 0.2 No 22 No 47.8 0.4 9530-05-009C Cs-137 0.875 0.0483 7/21/2004 4.6 No 29.8 No 38.0 5.9 9530-05-010C Co-60 0.111 0.0373 7/20/2004 0.2 No 22 No 55.5 0.5 95300-010 C Cs-1 37 0.557 0.0395 7/20/2004 4.6 No 29.8 No 24.2 3.7 95305-0 1C Co-60 0.243 0.0522 8/17/2004 0.2 Yes 22 No 121.5 1.1 9530-05-011C Cs-1 37 0.597 0.0527 8117/2004 4.6 No 29.8 No 26.0 4.0 9530-05-012C Cs-137 0.575 0.0366 8/17/2004 4.6 No 29.8 No 25.0 3.9 9530-05-013C Cs-137 0.225 0.0306 8/17/2004 4.6 No 29.8 No 9.8 1.5 9530-05-014C Co-60 0.128 0.0474 8/17/2004 . 0.2 No 22 No 64.0 0.6 9530-05-014C Cs-137 0.383 0.0456 8/17/2004 4.6 No 29.8 No 16.7 2.6 9530-05-015C Cs-137 0.423 0.0342 8/17/2004 4.6 No 29.8 No 18.4 2.8 Avg Cs-i137 (QCiIL) I 33.7 5.0 Avg Sr-90 (pCL) 5.8 l 1.3 Avg Co-60 (pCUL)L 322.5 1 2.9 Notes: 1)This value was calculated as Kdvalue* MCL Equivalent Concentration. The soil type wth the lowest Kd value was used Inthis case.

2) This value was calculated as Kd value ' MCL Equivalent Concentration. The soil type with the highest Kd value was used In this case.

3)This value was calculated as ipCUL = picocuries per Hlier 4)This value was calculated as measured soil concentrationlKd. The highest Kd was used. pCIlg = picocurfes per gram TPU = total propagated uncertainty MDC = minimum detectable concentration 1 of 1

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