Text

Environmental Report, Enclosure 2, Book 8 of 11
	ML12110A229
Person / Time
Site:	Limerick
Issue date:	02/28/2012
From:	; Exelon Nuclear
To:	; Office of Nuclear Reactor Regulation
References
	Download: ML12110A229 (272)
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Limerick Generating Station Units 1 & 2 License Renewal Project Environmental Report Response to Request for Additional Information (RAI) for the Review of LGS LRA ER, Dated February 28, 2012 Enclosure 2 Book 8 of 11

E2-22: Enclosure 2: Hydrology, item C Provide a summary of the results of groundwater monitoring performed for tritium, strontium-90, and gamma-emitting radionuclides since 2006 (i.e., groundwater protection program reports).

Exelon Response Copies of the Annual Radiological Groundwater Protection Program Reports for 2006 through 2010 are being provided.

1. Exelon Nuclear. 2007. Limerick Generating Station Units 1 and 2 Annual Radiological GroundwaterProtection ProgramReport, 1 JanuaryThrough 31 December2006. Prepared by Teledyne Brown Engineering Environmental Services. April.

2. Exelon Nuclear. 2008. Limerick GeneratingStation Units 1 and 2 Annual Radiological GroundwaterProtection ProgramReport, 1 January Through 31 December2007. Prepared by Teledyne Brown Engineering Environmental Services. April.

3. Exelon Nuclear. 2009. Limerick GeneratingStation Units 1and 2 Annual Radiological GroundwaterProtectionProgram Report, 1 January Through 31 December2008. Prepared by Teledyne Brown Engineering Environmental Services. April.

4. Exelon Nuclear. 2010. Limerick GeneratingStation Units 1and 2 Annual Radiological GroundwaterProtectionProgram Report, 1 January Through 31 December 2009. Prepared by Teledyne Brown Engineering Environmental Services. April.

5. Exelon Nuclear. 2011. Limerick GeneratingStation Units 1and 2 Annual Radiological GroundwaterProtection ProgramReport, 1 Januaiy Through 31 December 2010. Prepared by Teledyne Brown Engineering Environmental Services. April.

Docket No: 50-352 50-353 LIMERICK GENERATING STATION UNITS 1 and 2 Annual Radiological Groundwater Protection Program Report 1 January Through 31 December 2006 Prepared By Teledyne Brown Engineering Environmental Services Exelepn..

Nuclear Limerick Generating Station Sanatoga, PA 19464 April 2007

APPENDIX F ANNUAL RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM REPORT (ARGPPR)

Table Of Contents I. Sum mary and Conclusions ........................................................................................ 1 II. Introduction ..................................................................................................................... 3 A. Objectives of the RG PP ................................................................................. 3 B. Implementation of the Objectives .................................................................. 3 C. Program Description ...................................................................................... 4 D. Characteristics of Tritium (H-3) ...................................................................... 5 I1l. Program Description ................................................................................................ 5 A. Sam ple Analysis .................................................................................. I............... 6 B. Data Interpretation ......................................................................................... 6 C. Background Analysis ...................................................................................... 7

1. Background Concentrations of Tritium ..................................................... 8 IV. Results and Discussion ............................................................................................ 10 A. Groundwater Results .................................................................................... 10 B. Surface Water Results .................................. 11 C. Drinking W ater W ell Survey .......................................................................... 11 D. Summary of Results - Inter-laboratory Comparison Program ..................... 12 E. Leaks, Spills, and Releases .......................................................................... 12 F. Trends ........................................................................................................... 12 G. Investigations .............................................................................................. 12 H. Actions Taken .............................................................................................. 13 V. References .................................................................................................................. 13

Appendices Appendix A Location Designation TablAs-Table A-i Radiological Groundwater Protection Program - Sampling Locations, Distance and Direction, Limerick Generating Station, 2006 Figure 1 Phase 2 Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2006 Appendix B Data Tables Iablpas Table B-1.1 Concentrations of Tritium and Stronium-90 in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2006.

Table B-1.2 Concentrations of Gamma Emitters in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2006.

Table B-11.1 Concentrations of Tritium and Stronium-90 in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2006.

Table B-11.2 Concentrations of Gamma Emitters in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2006.

ii

I. Summary and Conclusions This report on the Radiological Groundwater Protection Program (RGPP) conducted for the Limerick Generating Station (LGS) by Exelon Nuclear covers the period 01 January 2006 through 31 December 2006.

In 2006, Exelon instituted a comprehensive program to evaluate the impact of station operations on groundwater and surface water in the vicinity of Limerick Generating Station. This evaluation involved numerous station personnel and contractor support personnel.

This is the first in a series of annual reports on the status of the RGPP conducted at LGS. This report covers groundwater and surface water samples, collected from the environment, both on and off station property in 2006. During that time period, 179 analyses were performed on 64 samples from 29 locations.

The monitoring was conducted in two phases. Phase 1 of the monitoring was part of a comprehensive study initiated by Exelon to determine whether groundwater or surface water at and in the vicinity of Limerick Generating Station had been adversely impacted by any releases of radionuclides.

Phase 1 was conducted by Conestoga Rovers and Associates (CRA) and the conclusions were made available to state and federal regulators as well as the public on an Exelon web site www.exeloncorp.com/ourcompanies/powergen/nucl;ar/Tritium.htm Phase 2 of the RGPP was conducted by Exelon corporate and station personnel to initiate follow up of Phase 1 and to begin long-term monitoring at groundwater and surface water locations selected during Phase 1. All analytical results from both the Phase 1 and Phase 2 monitoring are reported herein.

In assessing all the data gathered for this report, it was concluded that the operation of Limerick Generating Station had no adverse radiological impact on the environment offsite of LGS. There are no know active releases into the groundwater at Limerick Generating Station.

Gamma-emitting radionuclides associated with licensed plant operations were not detected at concentrations greater than their respective Lower Limits of Detection (LLDs) as specified in the Offsite Dose Calculation Manual (ODCM) in any of the groundwater or surface water samples. In the case of tritium, Exelon specified that it's laboratories achieve a lower limit of detection 10 times lower than that required by federal regulation.

Strontium-90 was not detected at a concentration greater than the LLD of 2.0 picoCuries per liter (pCi/L) in any of the groundwater or surface water samples tested.

Tritium was not detected in any of the groundwater or surface water samples at concentrations greater than the United States Environmental Protection Agency (USEPA) drinking water standard (and the Nuclear Regulatory Commission Reporting Limit) of 20,000 pCi/L. Low levels of tritium were detected at concentrations greater than the LLD of 200 pCi/L in 10 of 29 groundwater monitoring locations. The tritium concentrations ranged from 158 +/- 103 pCi/L to 4,360 +/- 494 pCi/L. Most of the tritium that was detected in groundwater at the Station is on the west side of the Turbine building. It is likely that the tritium has migrated from the Unit 1 Condensate Storage Tank and or the auxiliary heating steam pipe leak to the monitoring well. The dose via the drinking water pathway was calculated at 0.451 mrem to a child (total body), which was 7.52% of the 10 CFR 50, Appendix I dose limit. All results for Sr-90 and gamma emitting nuclides were less than MDC.

II. Introduction The Limerick Generating Station (LGS), consisting of two 3458 MWt boiling water reactors owned and operated by Exelon Corporation, is located adjacent to the Schuylkill River in Montgomery County, Pennsylvania. Unit No. 1 went critical on 22 December 1984. Unit No. 2 went critical on 11 August 1989. The site is located in Piedmont countryside, transversed by numerous valleys containing small tributaries that feed into the Schuylkill River. On the eastern river bank elevation rises from approximately 110 to 300 feet mean sea level (MSL). On the western river bank elevation rises to approximately 50 feet MSL to the western site boundary.

This report covers those analyses performed by Teledyne Brown Engineering (TBE) on samples collected in 2006.

A. Objective of the RGPP The long-term objectives of the RGPP are as follows:

1. Identify suitable locations to monitor and evaluate potential impacts from station operations before significant radiological impact to the environment and potential drinking water sources.

2. Understand the local hydrogeologic regime in the vicinity of the station and maintain up-to-date knowledge of flow patterns on the surface and shallow subsurface.

3. Perform routine water sampling and radiological analysis of water from selected locations.

4. Report new leaks, spills, or other detections with potential radiological significance to stakeholders in a timely manner.

5. Regularly assess analytical results to identify adverse trends.

6. Take necessary corrective actions to protect groundwater resources.

B. Implementation of the Objectives The objectives identified have been implemented at Limerick Generating Station as discussed below:

1. Exelon and its consultant identified locations as described in the Phase 1 study. Phase 1 studies were conducted by Connestoga Rovers and Associates (CRA) and the results and conclusions were made available to state and federal regulators as well as the public on an Exelon web site in station specific reports.

www-exeloncorp-com/ouroom pniesfpowearen/nucle r/Tritiu htm

2. The Limerick Generating Station reports describe the local hydrogeologic regime. Periodically, the flow patterns on the surface and shallow subsurface are updated based on ongoing measurements.

3. Limerick Generating Station will continue to perform routine sampling and radiological analysis of water from selected locations.

4. Limerick Generating Station has implemented new procedures to identify and report new leaks, spills, or other detections with potential radiological significance in a timely manner.

5. Limerick Generating Station staff and consulting hydrogeologist assess analytical results on an ongoing basis to identify adverse trends.

C. Program Description Samples for the LGS RGPP Phase 1 were collected for Exelon Nuclear by Conestoga Rovers and Associates (CRA) and samples for Phase 2 were collected by on-site personnel and Normandeau Associates, RMC Environmental Services Division (RMC). This section describes the general collection methods used to obtain environmental samples for the LGS RGPP in 2006. Sample locations can be found in Table A-i, Appendix A.

1. Sample Collection Groundwater and Surface Water Samples of water were collected,. managed, transported and analyzed in accordance with approved procedures following EPA methods. Both groundwater and surface water were collected.

Sample locations, sample collection frequencies and analytical frequencies were controlled in accordance with approved station procedures. Contractor and/or station personnel were trained in the collection, preservation management, and shipment of samples, as well as in documentation of sampling events.

Analytical laboratories were subject to internal quality assurance programs, industry cross-check programs, as well as nuclear industry audits. Station personnel reviewed and evaluated all analytical data deliverables as data were received.

Analytical data results were reviewed by both station personnel and an independent hydrogeologist for adverse trends or changes to hydrogeologic conditions.

D. Characteristics of Tritium (H-3)

Tritium (chemical symbol H-3) is a radioactive isotope of hydrogen. The most common form of tritium is tritium oxide, which is also called "tritiated water." The chemical properties of tritium are essentially those of ordinary hydrogen.

Tritiated water behaves the same as ordinary water in both the environment and the body. Tritium can be taken into the body by drinking water, breathing air, eating food, or absorption through skin. Once tritium enters the body, it disperses quickly and is uniformly distributed throughout the body. Tritium is excreted primarily through urine with a clearance rate characterized by an effective biological half-life of about 14 days. Within one month or so after ingestion, essentially all tritium is cleared. Organically bound tritium (tritium that is incorporated in organic compounds) can remain in the body for a longer period.

Tritium is produced naturally in the upper atmosphere when cosmic rays strike air molecules. Tritium is also produced during nuclear weapons explosions, as a by-product in reactors producing electricity, and in special production reactors, where the isotopes lithium-7 and/or boron-1 0 are activated to produce tritium. Like normal water, tritiated water is colorless and odorless. Tritiated water behaves chemically and physically like non-tritiated water in the subsurface, and therefore tritiated water will travel at the same velocity as the average groundwater velocity.

Tritium has a half-life of approximately 12.3 years. It decays spontaneously to helium-3 (3He). This radioactive decay releases a beta particle (low-energy electron). The radioactive decay of tritium is the source of the health risk from exposure to tritium. Tritium is one of the least dangerous radionuclides because it emits very weak radiation and leaves the body relatively quickly. Since tritium is almost always found as water, it goes directly into soft tissues and organs. The associated dose to these tissues is generally uniform and is dependent on the water content of the specific tissue.

Ill. Program Description A. Sample Analysis This section describes the general analytical methodologies used by TBE to analyze the environmental samples for radioactivity for the Limerick Generating Station RGPP in 2006.

In order to achieve the stated objectives, the current program includes the following analyses:

1. Concentrations of gamma emitters in groundwater and surface water.

2. Concentrations of strontium in groundwater and surface water.

3. Concentrations of tritium in groundwater and surface water.

B. Data Interpretation The radiological data collected prior to Limerick Generating Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, Limerick Generating Station was considered operational at initial criticality. Several factors were important in the interpretation of the data:

1. Lower Limit of Detection And Minimum Dntetabhle Concentration The lower limit of detection (LLD) is defined as the smallest concentration of radioactive material in a sample that would yield a net count (above background) that would be detected with only a 5% probability of falsely concluding that a blank observation represents a "real" signal. The LLD is intended as a before the fact estimate of a system (including instrumentation, procedure and sample type) and not as an after the fact criterion for the presence of activity. All analyses were designed to achieve the required LGS detection capabilities for environmental sample analysis.

The minimum detectable concentration (MDC) is defined above with the exception that the measurement is an after the fact estimate of the presence of activity.

2. Laboratorv Measurements Uncertainty The estimated uncertainty in measurement of tritium in environmental samples is frequently on the order of 50% of the measurement value.

Statistically, the exact value of a measurement is expressed as a range with a stated level of confidence. The convention is to report results with a 95% level of confidence. The uncertainty comes from calibration standards, sample volume or weight measurements, sampling uncertainty and other factors. Exelon reports the uncertainty of a measurement created by statistical process (counting error) as well as all sources of error (Total Propagated Uncertainty or TPU). Each result has two values calculated. Exelon reports the TPU by following the result with plus or minus +/- the estimated sample standard deviation, as TPU, that is obtained by propagating all sources of analytical uncertainty in measurements.

Analytical uncertainties are reported at the 95% confidence level in this report for reporting consistency with the AREOR.

C. Background Analysis A pre-operational radiological environmental monitoring program (pre-operational REMP) was conducted to establish background radioactivity levels prior to operation of the Station. The environmental media sampled and analyzed during the pre-operational REMP were atmospheric radiation, fall-out, domestic water, surface water, aquatic life, and foodstuffs. The results of the monitoring were detailed in the report entitled, Pre-operational Radiological Environmental Monitoring Program Report, Limerick Generating Station Units 1 and 2, 1 January 1982 through 21 December 1984, Teledyne Isotopes and Radiation Management Corporation.

The pre-operational REMP contained analytical results from samples collected from both surface water and groundwater.

Monthly surface water sampling began in 1982, and the samples were analyzed for tritium as well as other radioactive analytes. During the preoperational program tritium was detected at a maximum concentration of 420 pCi/L, indicating that these preoperational results were from nuclear weapons testing and are radioactively decaying as predicted.

Gamma isotopic results from the preoperational program were all less than or at the minimum detectable concentration (MDC) level.

1. Background Concentrations of Tritium The purpose of the following discussion is to summarize background measurements of tritium in various media performed by others. Additional detail may be found by consulting references.

a. Tritium Production Tritium is created in the environment from naturally occurring processes both cosmic and subterranean, as well as from anthropogenic (i.e., man-made) sources. In the upper atmosphere, "Cosmogenic" tritium is produced from the bombardment of stable nuclides and combines with oxygen to form tritiated water, which will then enter the hydrologic cycle. Below ground, "lithogenic" tritium is produced by the bombardment of natural lithium present in crystalline rocks by neutrons produced by the radioactive decay of naturally abundant uranium and thorium. Lithogenic production of tritium is usually negligible compared to other sources due to the limited abundance of lithium in rock. The lithogenic tritium is introduced directly to groundwater.

A major anthropogenic source of tritium and strontium-90 comes from the former atmospheric testing of thermonuclear weapons. Levels of tritium in precipitation increased significantly during the 1950s and early 1960s, and later with additional testing, resulting in the release of significant amounts of tritium to the atmosphere. The Canadian heavy water nuclear power reactors, other commercial power reactors, nuclear research and weapons production continue to influence tritium concentrations in the environment.

b. Precipitation Data Precipitation samples are routinely collected at stations around the world for the analysis of tritium and other radionuclides. Two publicly available databases that provide tritium concentrations in precipitation are Global Network of Isotopes in Precipitation (GNIP) and USEPA's RadNet database. GNIP provides tritium precipitation concentration data for samples collected world wide from 1960 to 2006.

RadNet provides tritium precipitation concentration data for samples collected at stations through out the. U.S. from 1960 up to and including 2006. Based on GNIP data for sample stations located in the U.S. Midwest, tritium concentrations peaked around 1963. This peak, which approached 10,000 pCi/L for some stations, coincided with the atmospheric testing of thermonuclear weapons. Tritium concentrations in surface water showed a sharp decline up until 1975 followed by a gradual decline since that time. Tritium concentrations in have typically been below 100 pCi/L since around 1980.

Tritium concentrations in wells may still be above the 200 pCi/L detection limit from the external causes described above. Water from previous years was naturally captured in groundwater. As a result, some well water sources today are affected by the surface water from the 1960s that contained elevated tritium activity.

c. Surface Water Data Tritium concentrations are routinely measured in the Schuylkill and Delaware Rivers. Pennsylvania surface water data are typically less than 100 pCi/L.

The USEPA RadNet surface water data typically has a reported 'Combined Standard Uncertainty' of 35 to 50 pCi/L.

According to USEPA, this corresponds to a +/-70 to 100 pCi/L 95% confidence bound on each given measurement.

Therefore, the typical background data provided may be subject to measurement uncertainty of approximately +/-70 to 100 pCi/L.

The radio-analytical laboratory is counting tritium results to an Exelon specified LLD of 200 pCi/L. Typically, the lowest positive measurement will be reported within a range of 40 -

240 pCi/L or 140 +/- 100 pCi/L. Clearly, these sample results cannot be distinguished as different from background at this concentration.

IV. Results and Discussion Gamma spectroscopy results for groundwater and surface water sample were reported for twelve nuclides (Mn-54, Co-58, Fe-59, Co-60, Zn-65, Nb-95, Zr-95, 1-131, Cs-134, Cs-137, Ba-140 and La-140).

A. Groundwater Results Samples were collected from onsite wells throughout the year in accordance with the station radiological groundwater protection program.

Analytical results and anomalies are discussed below.

Samples from 16 locations were analyzed for tritium activity (Table B-l.1, Appendix B). Tritium values ranged from <165 to 4,360 pCi/L. Well P-12 had the highest value of 4,360 pCi/L. After the results from well P-12 were confirmed well MW-LR-9 was dug directly over P-12 to the aquifer depth. Results from well MW-LR-9 ranged from <171 to 1,500 pCi/L. It was likely that tritium had migrated from the Unit 1 Condensate Storage Tank and or the auxiliary heating steam pipe leak to monitoring wells P-12 and MW-LR-9. The tritium migration pathway could be directly from the Unit 1 Condensate Storage Tank dike through bedrock fractures to P-12 and MW-LR-9. However, a more likely pathway is from the Unit 1 Condensate Storage Tank dike and or the auxiliary heating steam pipe leak through bedrock fractures to the drain system around the power block and into the Power Block Foundation Sump. From the drain system, the tritiated water could then migrate through bedrock fractures to P-12 and MW-LR-9. No other wells showed any elevated tritium results indicated that this contamination was localized to wells P-12 and MW-LR-

9. The dose via the drinking water pathway was calculated at 0.451 mrem to a child (total body), which was 7.52% of the 10 CFR 50, Appendix I dose limit.

Straontum No Sr-90 activity was detected in any of the ground water samples analyzed (Table B-1.1, Appendix B).

Gamma Emitters Potassium-40 was detected in four of 38 samples. The concentrations ranged from 58 pCi/Liter to 119 pCi/Liter. No other gamma emitting nuclides were detected (Table B-1.2, Appendix B).

B. Surface Water Results In accordance with the Station's radiological groundwater protection program surface water samples were collected from streams that transverses the site, as well as, from other water bodies that could influence the tritium concentration at Limerick. Analytical results and anomalies are discussed below.

Samples from 13 locations were analyzed for tritium activity (Table B-1.3, Appendix B). Tritium values ranged from <141 to 2,020 pCi/L The Foundation Power Block Sump (FPBS) had the highest value of 2,020 pCiIL. The FPBS is located in the general area of wells P-12 and MW-LR-9.

Stro2ntiuma No Sr-90 activity was detected in any of surface water samples analyzed (Table B-1.3, Appendix B).

Gamma EImitters No gamma emitting nuclides were detected in any of the surface water samples analyzed (Table B-1.4, Appendix B).

C. Drinking Water Well Survey A drinking water well survey was conducted during the summer 2006 by CRA (CRA 2006) around the Limerick Generating Station. CRA reviewed the Pennsylvania Groundwater Information System database to identify wells within a 1-mile radius from the center of the Station. Forty-six domestic withdrawal wells, two industrial wells, two commercial wells, and one institutional well were identified within the specified radius. The well depths range from 78 to 345 feet bgs, and they yield between 8 and 100 gallons per minute (gpm). All wells are completed in the Brunswick Formation.

The Station has one potable supply well and one fire water well. The potable supply well is constructed as an open-rock borehole. Groundwater was measured at a depth 102 feet bgs during a well pump replacement in 2004 (personal communication with Station, 2006). The pump was placed at a depth of approximately 294 feet bgs. The total well depth and the depth of the steel casing are unknown. The well is located approximately 175 feet east of the Reactor Building. The Station estimates that the well is pumped at approximately 2 gpm. The fire water well is constructed as an open-rock borehole. Groundwater was encountered at 121 feet bgs during a well pump replacement in 2004. The well pump was placed at a depth of approximately 399 feet bgs. The total well depth and the depth of the steel casing are unknown. The well is located approximately 500 feet east of the cooling towers. The well is used only in an emergency fire situation; therefore, water use is estimated to be zero.

D. Summary of Results - Inter-Laboratory Comparison Program Inter-Laboratory Comparison Program results for TBE are presented in the Annual Radiological Environmental Operating Report.

E. Leaks, Spills, and Releases The Station records inadvertent release of radioactive liquids in accordance with 10 CFR 50.75)g). As part of the fleet wide assessment, a third party environmental engineering firm was contracted to evaluate historic releases, and determine ifa potential pathway to the environment existed. Those releases that were determined to have potentially impacted groundwater were subsequently investigated as part of the fleet wide assessment. The hydrogeologic investigation determined that there is currently one radiological impacts to groundwater that is limited to the LGS site protected area boundary.

F. Trends No trends have been identified.

G. Investigations Conclusions from the Phase 1 report have been made available to state and federal regulators and to the public. Currently no investigations are on going.

H. Actions Taken

1. Compensatory Actions There have been no station events requiring compensatory actions at the Limerick Generating Station.

2. Installation of Monitoring Wells After phase 1 was completed two additional wells were added to the program. Wells MW-LR-8 and MW-LR-9 were drilled near the Unit 1 condensate storage tank dike to monitor groundwater tritium levels in that area. No new wells were required to be installed as a result of the phase 2 study.

3. Actions to Recover/Reverse Plumes No actions were required to recover or reverse groundwater plumes.

V. References

1. Conestoga Rovers and Associates, Fleetwide Assessment, Limerick Generating

Station, Sanatoga, Pennsylvania, Ref. No. 045136(17), September 2006

2. Pre-operational Radiological Environmental Monitoring Program Report, Limerick Generating Station Units 1 and 2, 1 January 1982 through 21 December 1984, Teledyne Isotopes and Radiation Management Corporation.

Intentionally Left Blank APPENDIX A LOCATION DESIGNATION

TABLE A-1: Radiological Groundwater Protection Program - Sampling locations for the Limerick Generating Station, 2006 I ,,L*% tfi Tuuia niafanfýg% Qf"Fl Phnom

%# g of - X MW-LR-1 Monitoring Well Onsite 1,2 MW-LR-2 Monitoring Well Onsite 1,2 MW-LR-3 Monitoring Well Onsite 1,2 MW-LR-4 Monitoring Well Onsite 1,2 MW-LR-5 Monitoring Well Onsite 1,2 MW-LR-6 Monitoring Well Onsite 1,2 MW-LR-7 Monitoring Well Onsite 1,2 MW-LR-8 Monitoring Well Onsite 1,2 MW-LR-9 Monitoring Well Onsite 2 Pll Monitoring Well Onsite 2 P12 Monitoring Well Onsite 1 P14 Monitoring Well Onsite 1,2 P16 Monitoring Well Onsite 1,2 P17 Monitoring Well Onsite 1,2 P3 Monitoring Well Onsite 1,2 SP22 Monitoring Well Onsite 1,2 SW-LR-1 Surface Water Of fsite 1,2 SW-LR-2 Surface Water Offsite 1 SW-LR-3 Surface Water Offsite 1 SW-LR-4 Surface Water Offsite 1 SW-LR-5 Surface Water Offsite 1 SW-LR-6 Surface Water Offsite 1 SW-LR-7 Surface Water Onsite 1 SW-LR-8 Surface Water Onsite 1,2 SW-LR-9 Surface Water Onsite 1,2 POWER BLOCK SUMP Surface Water Onsite 1 STILL CREEK Surface Water Offsite 1 BRADSHAW RESERVE Surface Water Offsite 1 WADESVILLE MINE Surface Water Offsite 1 A-1

Figure 1 Phase 2 Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2006 A-2

APPENDIX B DATA TABLES

TABLE B-4.1 CONCENTRATIONS OF TRITIUM AND STRONIUM-90 IN WELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION 2006 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION H-3 SR-90 STC DATE MW-LR-1 05/17/06 183 < 0.72 MW-LR-1 10/17/06 181 < 0.91 MW-LR-2 05/18/06 184 < 0.9 MW-LR-2 DUP 05/18/06 169 < 1.41 MW-LR-2 10/16/06 181 *

< 1.35 MW-LR-2 10/17/06 185 < 0.92 MW-LR-3 .05/18/06 170 < 1.18 MW-LR-3 10/18/06 180 t

< 1.33 MW-LR-4 05/19/06 222 +/- 118 < 0.8 MW-LR-4 10/17/06 < 185 * < 1.4 MW-LR-5 05/19/06 305 +/- 121 < 0.79 MW-LR-5 10/18/06 < 183 < 1.11 MW-LR-5 10/18/06 236 +/- 118* < 1.49 MW-LR-5 10/18/06 275 +/- 137* < 1.42 MW-LR-5 10/18/06 247 +/- 118*

MW-LR-5 10/18/06 209 +/- 129*

MW-LR-6 05/17/06 182 1.35 MW-LR-6 10/16/06 180 1.35 MW-LR-6 10/17/06 175 1.34 MW-LR-7 05/18/06 166 1.16 MW-LR-7 10/16/06 181 1.49 MW-LR-7 10/18/06 167 1.47 MW-LR-8 06/28/06 184 +/- 116 MW-LR-8 07/07/06 244 + 116*

MW-LR-8 08/16/06 246 +/- 124* < 1.56 MW-LR-8 10/18/06 < 180 < 1.37

INDICATES DISTILLED ANALYSIS B-i

TABLE B-1.1 CONCENTRATIONS OF TRITIUM AND STRONIUM-90 IN WELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION 2006 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LOCATION DATE H-3 SR-90 MW-LR-9 08/16/06 1500 +/- 210* 1.24 MW-LR-9 10/19/06 < 171

1.33 MW-LR-9 10/19/06 238 +/- 120" 1.36 MW-LR-9 10/19/06 172 MW-LR-9 10/19/06 180 Pll 05/18/06 < 184 < 1.35 P1l 10/17/06 204 +/- 118* < 1.48 P1l 10/17/06 < 187 * < 0.81 P11 DUP 05/18/06 < 185 P12 05/18/06 4360 +/- 494 < 1.3 P12 05/18/06 4350 +/- 199 P14 05/18/06 185 0.89 P14 10/17/06 180 t 1.36 P16 05/18/06 < 182 < 0.94 P17 05/17/06 183 1.37 P17 10/18/06 174 1.48 P3 05/18/06 170 1.12 P3 10/19/06 178 1.46 SP22 05/19/06 165 0.55 SP22 10/17/06 185 1.4

INDICATES DISTILLED ANALYSIS B-2

TABLE B-1.2 CONCENTRATIONS OF GAMMA EMITTERS INWELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, MMERICK GENERATING STATION 2006 RESULTS IN UNITS OF PCI/UTER +/- 2 SIGMA COLLECTION STC DATE BE-7 K-40 MN-54 CO-58 FE-59 CO-60 ZN-65 NB-95 ZR-95 1-131 CS-134 CS-137 BA-140 LA-140 ZN-65 NS-95 ZR-95 MW-LR-1 05/17/06 < 25 < 29K-40 <3 <3 <6 CO-60

<3 < 10 <4 <5 <4 <6 < 3 < 12 <4 MW-LR-1 10/17/06 < 37 <33 <4 <5 <9 <6 < 10 <5 <9 <12 <4 <4 < 26 <7 MW-LR-2 05/18/06 41 < 43 <5 5 <9 5 16 6 9 8 <8 5 22 7 MW-LR-2 10/16/06 43 58 +/-46 <5 5 < 10 6 9 6 9 14 <4 5 30 12 MW-LR-2 10/17/06 33 < 61 <3 3 <7 3 6 4 6 9 <3 4 23 8 MW-LR-2 DUP 05/18/06 29 < 31 <3 3 <6 3 12 4 6 5 <7 4 14 5 MW-LR-3 05/18/06 < 45 < 56 <5 <6 <11 <6. <16 <6 <9 <8 <8 <6 <22 <<8 MW-LR-3 10/18/06 < 51 < 52 <5 <5 <11 <4 <11 <6 <9 <14 <4 <5 <36 <11 MW-LR-4 05/19/06 < 45 < 56 <6 <5 <12 <5 <14 <6 <9 <8 <6 <5 <24 < 9 MW-LR-4 10/17/06 < 39 < 85 <4 <4 <8 <4 <8 <4 <7 <12 <4 <4 < 28 < 11 MW-LR-5 05/19/06 50 < 72 <6 < 6 < 11 6 22 7 9 9 < 10 <6 24 8 MW-LR-5 10/18/06 48 < 74 <4 < 4 <8 5 10 5 8 14 <4 <5 30 12 MW-LR-5 10/18/06 40 < 99 < 4 < 4 <7 4 8 5 8 15 <4 <4 33 10 MW-LR-5 10/18/06 38 < 42 < 5 < 5 < 11 7 8 5 9 15 <4 <4 32 11 MW-LR-6 05/17/06 27 < 50 < 3 < 3 <6 4 9 4 6 4 <5 <4 13 5 MW-LR-6 10/16/06 49 < 50 < 4 < 5 < 14 5 11 6 9 16 <4 <5 35 9 MW-LR-6 10/17/06 43 119 +/- 61 < 5 < 6 < 11 7 10 5 10 16 <6 <6 35 12 MW-LR-7 05/18/06 < 29 < 49 <3 <3 <7 <3 <12 <4 <6 <5 <6 <4 <15 <5 MW-LR-7 10/16/06 < 20 < 18 <2 <2 <5 <3 <4 <2 <4 <7 <2 <2 <15 <5 MW-LR-7 10/18/06 < 45 < 93 <5 <5 <12 <7 <10 <6. <9 <14 <5 <6 <31 <8 B-3

TABLE B-I.2 CONCENTRATIONS OF GAMMA EMrITERS IN WELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, UMERICK GENERATING STATION 2006 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA STc DATE BE-7 K-40 MN-54 CO-58 FE-59 CO-60 ZN-65 NB-95 ZR-95 1-131 CS-134 CS-137 BA-140 LA,140 MVW-LR-8 08/16/06 < 45 < 62 <6 <6 <13 <7 <10 <7 <10 <7 <5 <6 <25 <7 MW-LR-8 10/18/06 < 32 < 29 <3 <3 <8 <3 <6 <4 <6 <12 <3 <3 <26 <6 MW-LR-9 08/16/06 < 39 61 +/- 55 <5 <5 <10 <4 <8 <6 <7 <5 <4 <5 <17 <6 MW-LR-9 10/19/06 < 38 < 87 <4 <4 <12 <5 <7 <5 <9 <14 <4 <5 <31 <9 MW-LR-9 10/19/06 < 35 < 79 <3 <4 <9 <4 <5 <4 <7 <12 <4 <4 <27 <7 Pl1 05/18/06 < 48 < 48 <5 <5 <11 <6 <15 <7 <9 <8 <7 <6 <23 <7 P1l 10/17/06 < 43 79 +/- 49 <5 <4 <11 <4 <10 <5 <8 <16 <4 <4 < 29 < 14 P11 DUP 05/18/06 < 43 < 52 <5 <5 <10 <5 <16 <5 <9 <8 <8 <6 <22 <8 P12 05/18/06 < 39 < 76 <5 <5 <8 <4 <14 <5 <8 <7 <7 <5 <21 <6 P14 05/18/06 < 46 < 56 < 5 <5 <10 <6 <13 <6 <9 <8 <6 <6 <25 <8 P14 10/17/06 < 43 < 116 <4 <5 <10 <3 < 10 <5 < 10 < 16 <4 <5 <33 <12 P16 05/18(06 < 47 < 50 < 5 <6 < 13 <6 <16 <6 <9 <9 <7 <6 <22 <9 P17 05/17/06 < 33 < 62 <4 <4 <8 <4 <9 <4 <7 <5 <5 <4 <16 <5 P17 10/18/06 < 52 < 97 <5 <5 <10 <5 <8 <6 < 10 < 13 <5 <5 <34 <12 P3 05/18/06 < 38 < 46 <5 <5 <9 <4 <13 <5 <8 <6 <6 <5 <20 <7 P3 10/19/06 < 42 < 40 <4 <5 <10 <5 <10 <5 <7 <12 <4 <4 <29 <10 SP22 05/19/06 < 53 < 52 <5 <6 <12 <6 < 14 <6 < 10 <9 <7 <6 <27 <9 SP22 10/17/06 < 42 < 74 <4 <5 <11 <5 <9 <6 <8 <16 <4 <4 <34 <13 B-4

TABLE B-11.1 CONCENTRATIONS OF TRITIUM AND STRONIUM-90 IN SURFACE WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION 2006 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LOCATION DATE H-3 SR-90 SW-LR-1 05/22/06 < 150 < 1.5 SW-LR-1 10/16/06 < 187 * < 1.59 SW-LR-2 05/22/06 < 152 < 1.46 SW-LR-3 05/22/06 < 154 < 1.59 SW-LR-4 05/22/06 158 +/- 103 < 1.49 SW-LR-5 05/22/06 < 141 < 1.23 SW-LR-5 DUP 05/22/06 < 152 < 1.89 SW-LR-6 05/22/06 184 +/- 108 < 1.35 SW-LR-7 05/22/06 < 150 < 1.84 SW-LR-8 05/19/06 523 +/- 137 < 0.7 SW-LR-8 10/16/06 < 176 < 1.26 SW-LR-9 05/19/06 < 166 < 1.15 SW-LR-9 10/16/06 < 183 * < 1.5 SW-LR-9 DUP 05/19/06 < 172 < 0.89 BRADSHAW RESERVOIR 05/31/06 < 166 < 1.73 POWER BLOCK SUMP 05/31/06 2020 + 154 < 1.83 STILL CREEK 05/31/06 < 165 < 1.63 WADESVILLE MINE 05/31/06 < 165 < 1.28

INDICATES DISTILLED ANALYSIS B-5

TABLE B-II.2 CONCENTRATIONS OF GAMMA EMITTERS INSURFACE WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, UMERICK GENERATING STATION 2006 RESULTS INUNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LOCATION DATE BE-7 K-40 MN-54 CO-58 FE-59 CO-60 ZN-65 NB-95 ZR-95 1-131 CS-134 CS-137 BA-140 LA-140 SW-LR-1 05/2206 < 16 < 19 <2 <2 <4 <2 <5 <2 <3 <3 <2 <2 <9 <3 SW-LR-1 10/16'06 < 37 < 76 <4 <4 <8 <4 <8 <4 <7 <12 <4 <4 <27 <6 SW-LR-2 05/22/06 < 48 < 47 <5 <5 <9 <5 <11 <5 <10 <9 <6 <5 <23 <8 SW-LR-3 05/22/06 < 30 < 33 <3 <3 <7 <4 <7 <3 <6 <6 -<4 <3 < 17 <5 SW-LR-4 05/22/06 < 30 < 33 <3 <4 <7 <3 <8 <4 <6 <6 <4 <4 < 16 <5 SW-LR-5 05/22/06 < 43 < 46 <5 <5 <9 <5 <10 <5 <9 <9 <5 <5 <23 <8 SW-LR-5 DUP 05/22/06 < 34 < 65 <4 <4 <8 <4 <9 <4 <7 <7 <5 <4 <:20 <6 SW-LR-6 05/22/06 < 43 < 45 <6 <5 <11 <5 <14 <6 <9 <10 <6 <5 <26 <8 SW-LR-7 05/22/06 < 48 < 87 < 5 <5 <10 <5 <12 <5 <9 <10 <5 <5 <25 <9 SW-LR-8 05/19/06 < 45 < 49 <4 <5 <9 <5 <11 <5 <8 <8 <5 <5 <22 <7 SW-LR-8 10/16/06 < 40 < 117 <4 <4 <9 <3 <8 <4 <10 <16 <4 <4 <35 <11 SW-LR-9 05/19/06 < 51 .< 50 <6 <6 <13 <6 <12 <6 <10 <9 <5 <7 < 27 <8 SW-LR-9 10/16(06 < 61 < 57 <6 <7 <15 <6 <14 <7 <8 <22 <6 <7 <53 <11 SW-LR-9 DUP 05/19/06 < 39 < 42 <5 <5 <10 <5 <10 <5 <8 <7 <5 <5 < 21 <7 BRADSHAW 05(31/06 < 56 < 53 <5 <6 <12 <5 <11 <6 <10 <20 <6 <6 <40 < 12 RESERVOIR POWER BLOCK 05/31/06 < 49 < 47 <5 <5 <12 <5 <12 <5 <10 <16 <6 <5 <37 < 12 SUMP STILL CREEK 05/31/06 < 49 < 46 <5 <5 <12 <5 <11 <6 <9 <17 <6 <5 <38 <12 WADESVI LLE MINE 05/31/06 < 47 < 40 <5 <5 <11 <4 <10 <5 <9 <16 <5 <5 <35 <11 B-6

Docket No: 50-352 50-353 LIMERICK GENERATING STATION UNITS I and 2 Annual Radiological Groundwater Protection Program Report 1 January Through 31 December 2007 Prepared By Teledyne Brown Engineering Environmental Services Exeltn Nuclear Limerick Generating Station Sanatoga, PA 19464 April 2008

Table Of Contents I. Sum m ary and Conclusions ................................................................................................ 1 II. Introduction ........................................................................................................................ 2 A. Objectives of the RGPP ................................... 2 B. Implem entation of the O bjectives .......................................................................... 2 C. Program Description ................................................. ..................................... 3 D. Characteristics of Tritium (H-3) ......................................................................... 4 Ill. Program Description ................................................................................................. 4 A. Sam ple Analysis ................................................................................................ 4 B. Data Interpretation ................................................................................................. 5 C. Background Analysis ........................................................................................ 6

1. Background Concentrations of Tritium .................................................. 6 IV. Results and Discussion .................................................... ....................................... 8 A. G roundwater Results ........................................................................................ 8 B. Surface Water Results ...................................................................................... 9 C. Drinking W ater Well Survey ............................................................................. 9 D. Summary of Results - Inter-laboratory Comparison Program ....................... 10 E. Leaks, Spills, and Releases ........................................................................... 10 F. Trends .............................. * .......... .................... ............................................. 11 G . Investigations ........................................................................... 11 H. Actions Taken ............................................................ .................................. 11 V. References ...................................................................................................................... 11 i

Appendices Appendix A Location Designation TableA Table A-I Radiological Groundwater Protection Program - Sampling Locations for the Limerick Generating Station, 2007 Figure 1 Figure 1 Routine Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2007 Appendix B Data Tables Table B-1.1 Concentrations of Tritium and Stronium-90 in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2007.

Table B-1.2 Concentrations of Gamma Emitters in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2007.

Table B-11.1 Concentrations of Tritium and Stronium-90 in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2007.

Table B-11.2 Concentrations of Gamma Emitters in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2007.

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I. Summary and Conclusions This report on the Radiological Groundwater Protection Program (RGPP) conducted for the Limerick Generating Station (LGS) by Exelon Nuclear covers the period 01 January 2007 through 31 December 2007.

In 2006, Exelon instituted a comprehensive program to evaluate the impact of station operations on groundwater and surface water in the vicinity of Limerick Generating Station. This evaluation involved numerous station personnel and contractor support personnel.

This report covers groundwater and surface water samples, collected from the environment, both on and off station property in 2007. During that time period, 90 analyses were performed on 36 samples from 21 locations.

In assessing all the data gathered for this report, it was concluded that the operation of Limerick Generating Station had no adverse radiological impact on the environment offsite of LGS. There are no know active releases into the groundwater at Limerick Generating Station.

Gamma-emitting radionuclides associated with licensed plant operations were not detected at concentrations greater than their respective Lower Limits of Detection (LLDs) as specified in the Offsite Dose Calculation Manual (ODCM) in any of the groundwater or surface water samples. In the case of tritium, Exelon specified that it's laboratories achieve a lower limit of detection 10 times lower than that required by federal regulation.

Strontium-90 was not detected at a concentration greater than the LLD of 2.0 picoCuries per liter (pCi/L) in any of the groundwater or surface water samples tested.

Tritium was not detected in any of the groundwater or surface water samples at concentrations greater than the United States Environmental Protection Agency (USEPA) drinking water standard (and the Nuclear Regulatory Commission Reporting Limit) of 20,000 pCi/L. Low levels of tritium were detected at concentrations greater than the LLD of 200 pCi/L in 4 of 15 groundwater monitoring locations. The tritium concentrations ranged from 201 to 309 pCi/L.

Although no drinking water pathway is available from groundwater, the dose via the drinking water pathway was calculated at 0.032 mrem to a child (total body),

which was 0.553% of the 10 CFR 50, Appendix I dose limit. All results for Sr-90 and gamma emitting nuclides were less than MDC.

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II. Introduction The Limerick Generating Station (LGS), consisting of two 3458 MWt boiling water reactors owned and operated by Exelon Corporation, is located adjacent to the Schuylkill River in Montgomery County, Pennsylvania. Unit No. 1 went critical on 22 December 1984. Unit No. 2 went critical on 11 August 1989. The site is located in Piedmont countryside, transversed by numerous valleys containing small tributaries that feed into the Schuylkill River. On the eastern river bank elevation rises from approximately 110 to 300 feet mean sea level (MSL). On the western river bank elevation rises to approximately 50 feet MSL to the western site boundary.

This report covers those analyses performed by Teledyne Brown Engineering (TBE) on samples collected in 2007.

A. Objective of the RGPP The long-term objectives of the RGPP are as follows:r

1. Identify suitable locations to monitor and evaluate potential impacts from station operations before significant radiological impact to the environment and potential drinking water sources.

2. Understand the local hydrogeologic regime in the vicinity of the station and maintain up-to-date knowledge of flow patterns on the surface and shallow subsurface.

3. Perform routine water sampling and radiological analysis of water from selected locations.

4. Report new leaks, spills, or other detections with potential radiological significance to stakeholders in a timely manner.

5. Regularly assess analytical results to identify adverse trends.

6. Take necessary corrective actions to protect groundwater resources.

B. Implementation of the Objectives The objectives identified have been implemented at Limerick Generating Station as discussed below:

1. Exelon and its consultant identified locations as described in the 2006 Phase 1 study. The Phase 1 study results and conclusions were made available to state and federal regulators as well as the public on an Exelon web site in station specific reports.

www.exeloncorgo.com/ourcompanie*.powerfen/nucrlear/Tritium-htm 2

2. The Limerick Generating Station reports describe the local hydrogeologic regime. Periodically, the flow patterns on the surface and shallow subsurface are updated based on ongoing measurements.

3. Limerick Generating Station will continue to perform routine sampling and radiological analysis of water from selected locations.

4. Limerick Generating Station has implemented new procedures to identify and report new leaks, spills, or other detections with potential radiological significance in a timely manner.

5. Limerick Generating Station staff and consulting hydrogeologist assess analytical results on an ongoing basis to identify adverse trends.

C. Program Description Samples for the ongoing ground water monitoring program were collected for Exelon Nuclear by Normandeau Associates, lnc.(NAI). This section describes the general collection methods used to obtain environmental samples for the LGS RGPP in 2007. Sample locations can be found in Table A-i, Appendix A.

1. Sample Collection Grnundwater and Surfare Water Samples of water were collected, managed, transported and analyzed in accordance with approved procedures following EPA methods. Both groundwater and surface water were collected.

Sample locations, sample collection frequencies and analytical frequencies were controlled in accordance with approved station procedures. Contractor and/or station personnel were trained in the collection, preservation management, and shipment of samples, as well as in documentation of sampling events. Analytical laboratories were subject to internal quality assurance programs, industry cross-check programs, as well as nuclear industry audits.

Station personnel reviewed and evaluated all analytical data deliverables as data were received.

Analytical data results were reviewed by both station personnel and an independent hydrogeologist for adverse trends or changes to hydrogeologic conditions.

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D. Characteristics of Tritium (H-3)

Tritium (chemical symbol H-3) is a radioactive isotope of hydrogen. The most common form of tritium is tritium oxide, which is also called "tritiated water." The chemical properties of tritium are essentially those of ordinary hydrogen.

Tritiated water behaves the same as ordinary water in both the environment and the body. Tritium can be taken into the body by drinking water, breathing air, eating food, or absorption through skin. Once tritium enters the body, it disperses quickly and is uniformly distributed throughout the body. Tritium is excreted primarily through urine with a clearance rate characterized by an effective biological half-life of about 14 days. Within one month or so after ingestion, essentially all tritium is cleared. Organically bound tritium (tritium that is incorporated in organic compounds) can remain in the body for a longer period.

Tritium is produced naturally in the upper atmosphere when cosmic rays strike air molecules. Tritium is also produced during nuclear weapons explosions, as a by-product in reactors producing electricity, and in special production reactors, where the isotopes lithium-7 and/or boron-10 are activated to produce tritium. Like normal water, tritiated water is colorless and odorless. Tritiated water behaves chemically and physically like non-tritiated water in the subsurface, and therefore tritiated water will travel at the same velocity as the average groundwater velocity.

Tritium has a half-life of approximately 12.3 years. It decays spontaneously to helium-3 (3He). This radioactive decay releases a beta particle (low-energy electron). The radioactive decay of tritium is the source of the health risk from exposure to tritium. Tritium is one of the least dangerous radionuclides because it emits very weak radiation and leaves the body relatively quickly. Since tritium is almost always found as water, it goes directly into soft tissues and organs. The associated dose to these tissues is generally uniform and is dependent on the water content of the specific tissue.

Ill. Program Description A. Sample Analysis This section describes the general analytical methodologies used by TBE to analyze the environmental samples for radioactivity for the Limerick Generating Station RGPP in 2007.

In order to achieve the stated objectives, the current program includes the following analyses:

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1. Concentrations of gamma emitters in groundwater and surface water.

2. Concentrations of strontium in groundwater and surface water.

3. Concentrations of tritium in groundwater and surface water.

B. Data Interpretation The radiological data collected prior to Limerick Generating Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, Limerick Generating Station was considered operational at initial criticality. Several factors were important in the interpretation of the data:

1. Lower Limit of Detection and Minimum Detectable Concentration The lower limit of detection (LLD) is defined as the smallest concentration of radioactive material in a sample that would yield a net count (above background) that would be detected with only a 5% probability of falsely concluding that a blank observation represents a "real" signal. The LLD is intended as a before the fact estimate of a system (including instrumentation, procedure and sample type) and not as an after the fact criterion for the presence of activity. All analyses were designed to achieve the required LGS detection capabilities for environmental sample analysis.

The minimum detectable concentration (MDC) is defined above with the exception that the measurement is an after the fact estimate of the presence of activity.

2. Laboratory Measurements Uncertainty The estimated uncertainty in measurement of tritium in environmental samples is frequently on the order of 50% of the measurement value.

Statistically, the exact value of a measurement is expressed as a range with a stated level of confidence. The convention is to report results with a 95% level of confidence. The uncertainty comes from calibration standards, sample volume or weight measurements, sampling uncertainty and other factors. Exelon reports the uncertainty of a measurement created by statistical process (counting error) as well as all sources of error (Total Propagated Uncertainty or TPU). Each result has two values calculated.

Exelon reports the TPU by following the result with plus or minus +/-

5

the estimated sample standard deviation, as TPU, that is obtained by propagating all sources of analytical uncertainty in measurements.

Analytical uncertainties are reported at the 95% confidence level in this report for reporting consistency with the AREOR.

C. Background Analysis A pre-operational radiological environmental monitoring program (pre-operational REMP) was conducted to establish background radioactivity levels prior to operation of the Station. The environmental media sampled and analyzed during the pre-operational REMP were atmospheric radiation, fall-out, domestic water, surface water, aquatic life, and foodstuffs. The results of the monitoring were detailed in the report entitled, Pre-operational Radiological Environmental Monitoring Program Report, Limerick Generating Station Units 1 and 2, 1 January 1982 through 21 December 1984, Teledyne Isotopes and Radiation Management Corporation.

The pre-operational REMP contained analytical results from samples collected from both surface water and groundwater.

Monthly surface water sampling began in 1982, and the samples were analyzed for tritium as well as other radioactive analytes. During the preoperational program tritium was detected at a maximum concentration of 420 pCi/L, indicating that these preoperational results were from nuclear weapons testing and are radioactively decaying as predicted.

Gamma isotopic results from the preoperational program were all less than or at the minimum detectable concentration (MDC) level.

1. Background Concentrations of Tritium The purpose of the following discussion is to summarize background measurements of tritium in various media performed by others. Additional detail may be found by consulting references.

a. Tritium Production Tritium is created in the environment from naturally occurring processes both cosmic and subterranean, as well as from anthropogenic (i.e., man-made) sources. In the upper atmosphere, "Cosmogenic" tritium is produced from the bombardment of stable nuclides and combines with oxygen to form tritiated water, which will then enter the hydrologic cycle. Belowground,%"lithogenic" tritium is produced by the 6

bombardment of natural lithium present in crystalline rocks by neutrons produced by the radioactive decay of naturally abundant uranium and thorium. Lithogenic production of tritium is usually negligible compared to other sources due to the limited abundance of lithium in rock. The lithogenic tritium is introduced directly to groundwater.

A major anthropogenic source of tritium and strontium-90 comes from the former atmospheric testing of thermonuclear weapons. Levels of tritium in precipitation increased significantly during the 1950s and early 1960s, and later with additional testing, resulting in the release of significant amounts of tritium to the atmosphere. The Canadian heavy water nuclear power reactors, other commercial power reactors, nuclear research and weapons production continue to influence tritium concentrations in the environment.

b. Precipitation Data Precipitation samples are routinely collected at stations around the world for the analysis of tritium and other radionuclides. Two publicly available databases that provide tritium concentrations in precipitation are Global Network of Isotopes in Precipitation (GNIP) and USEPA's RadNet database. GNIP provides tritium precipitation concentration data for samples collected world wide since 1960. RadNet provides tritium precipitation concentration data for samples collected at stations through out the U.S. Based on GNIP data for sample stations located in the U.S. Midwest, tritium concentrations peaked around 1963. This peak, which approached 10,000 pCi/L for some stations, coincided with the atmospheric testing of thermonuclear weapons. Tritium concentrations in surface water showed a sharp decline up until 1975 followed by a gradual decline since that time.

Tritium concentrations in have typically been below 100 pCi/L since around 1980. Tritium concentrations in wells may still be above the 200 pCi/L detection limit from the external causes described above. Water from previous years was naturally captured in groundwater. As a result, some well water sources today are affected by the surface water from the 1960s that contained elevated tritium activity.

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c. Surface Water Data Tritium concentrations are routinely measured in the Schuylkill and Delaware Rivers. Pennsylvania surface water data are typically less than 100 pCi/L.

The USEPA RadNet surface water data typically has a reported 'Combined Standard Uncertainty' of 35 to 50 pCi/L.

According to USEPA, this corresponds to a +/-70 to 100 pCi/L 95% confidence bound on each given measurement.

Therefore, the typical background data provided may be subject to measurement uncertainty of approximately +/- 70 to 100 pCi/L.

The radio-analytical laboratory is counting tritium results to an Exelon specified LLD of 200 pCi/L. Typically, the lowest positive measurement will be reported within a range of 40 -

240 pCi/L or 140 +/- 100 pCi/L. Clearly, these sample results cannot be distinguished as different from background at this concentration.

IV. Results and Discussion Gamma spectroscopy results for groundwater and surface water sample were reported for twelve nuclides (Mn-54, Co-58, Fe-59, Co-60, Zn-65, Nb-95, Zr-95, I-131, Cs-134, Cs-137, Ba-140 and La-140).

A. Groundwater Results Samples were collected from onsite wells throughout the year in accordance with the station radiological groundwater protection program.

Analytical results and anomalies are discussed below.

Samples from fifteen locations were analyzed for tritium activity (Table B-1.1, Appendix B). Tritium values ranged from non detectable to 309 pCi/L.

Well MW-LR-5 had the highest value of 309 pCi/L. Although no drinking water pathway is available from groundwater, the dose via the drinking water pathway was calculated at 0.032 mrem to a child (total body), which was 0.553% of the 10 CFR 50, Appendix I dose limit.

Strontium No Sr-90 activity was detected in any of the ground water samples analyzed (Table B-4.1, Appendix B).

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Gamma Fmittars Potassium-40 was detected in one of 15 samples at a concentration of 155 pCi/Liter. No other gamma emitting nuclides were detected (Table B-1.2, Appendix B).

B. Surface Water Results In accordance with the Station's radiological groundwater protection program surface water samples were collected from streams that transverses the site, as well as, from other water bodies that could influence the tritium concentration at Limerick. Analytical results and anomalies are discussed below.

Samples from six locations were analyzed for tritium activity No tritium activity was detected in any surface water samples analyzed (Table B-1.3, Appendix B).

No Sr-90 activity was detected in any of surface water samples analyzed (Table B-1.3, Appendix B).

Gamma Imitters No gamma emitting nuclides were detected in any of the surface water samples analyzed (Table B-1.4, Appendix B).

C. Drinking Water Well Survey A drinking water well survey was conducted during the summer 2006 by CRA (CRA 2006) around the Limerick Generating Station. CRA reviewed the Pennsylvania Groundwater Information System database to identify wells within a 1-mile radius from the center of the Station. Forty-six domestic withdrawal wells, two industrial wells, two commercial wells, and one institutional well were identified within the specified radius. The well depths range from 78 to 345 feet bgs, and they yield between 8 and 100 gallons per minute (gpm). All wells are completed in the Brunswick Formation.

The Station has one potable supply well and one fire water well. The potable supply well is constructed as an open-rock borehole. Groundwater was measured at a depth 102 feet bgs during a well pump replacement in 2004 (personal communication with Station, 2006). The pump was placed at a depth of approximately 294 feet bgs. The total well depth and the 9

depth of the steel casing are unknown. The well is located approximately 175 feet east of the Reactor Building. The Station estimates that the well is pumped at approximately 2 gpm. The fire water well is constructed as an open-rock borehole. Groundwater was encountered at 121 feet bgs during a well pump replacement in 2004. The well pump was placed at a depth of approximately 399 feet bgs. The total well depth and the depth of the steel casing are unknown. The well is located approximately 500 feet east of the cooling towers. The well is used only in an emergency fire situation; therefore, water use is estimated to be zero.

D. Summary of Results - Inter-Laboratory Comparison Program Inter-Laboratory. Comparison Program results for TBE are presented -in the Annual Radiological Environmental Operating Report.

E. Leaks, Spills, and Releases Tritium was discovered in the "C" aux boiler on 11/17/2007 (IR 700944)..

Activity found was 4030 pCi/L. Subsequent sampling of the Refuel Water Storage Tank (RWST) and the telltale indicator for the guard pipe from the condensate return line of the steam heat to the circulating water pump house (gooseneck) showed positive tritium, as well. The gooseneck was discharging directly to the ground, which resulted in a notification to the PA DEP per the Exelon radiological groundwater protection program procedure. Total time that tritiated water was being discharged to the ground was three days. On 11/20/2007 the discharge from the gooseneck was redirected to a drain that goes through the oil interceptors, oily waste separators, hold pond and then to radwaste discharge line to outfall 001.

The release rate was determined by operations as 2.9 gallons/minute.

Total volume released to the ground was calculated as 47,423 liters for the three days of discharge. The highest activity observed during that time period was 4850 pCi/L. Based upon this information a total of 2.3E+08 pCi were discharged to the ground. There is no drinking water pathway that could become contaminated from this release. Monitoring well P-1 1 is the closes well to the release. The maximum dose via the drinking water pathway was calculated at 0.502 mrem to a child (total body), which was 8.369% of the 10 CFR 50, Appendix I dose limit.

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F. Trends No trends have been identified.

G. Investigations Conclusions from the Phase I report have been made available to state and federal regulators and to the public. Currently no investigations are on going.

H. Actions Taken

1. Compensatory Actions There have been no station events requiring compensatory actions at the Limerick Generating Station.

2. Installation of Monitoring Wells No new wells have been installed in 2007

3. Actions to Recover/Reverse Plumes No actions were required to recover or reverse groundwater plumes.

V. References

1. Conestoga Rovers and Associates, Fleetwide Assessment, Limerick Generating Station, Sanatoga, Pennsylvania, Ref. No. 045136(17), September 2006

2. Pre-operational Radiological Environmental Monitoring Program Report, Limerick Generating Station Units I and 2, 1 January 1982 through 21 December 1984, Teledyne Isotopes and Radiation Management Corporation.

11

APPENDIX A LOCATION DESIGNATION

TABLE A-1: Radiological Groundwater Protection Program - Sampling Locations for the Limerick Generating Station, 2007 Location Type Distance MW-LR-1 Monitoring Well Onsite MW-LR-2 Monitoring Well Onsite MW-LR-3 Monitoring Well Onsite MW-LR-4 Monitoring Well Onsite MW-LR-5 Monitoring Well Onsite MW-LR-6 Monitoring Well Onsite MW-LR-7 Monitoring Well Onsite MW-LR-8 Monitoring Well Onsite MW-LR-9 Monitoring Well Onsite Pll .Monitoring Well Onsite P14 Monitoring Well Onsite P16 Monitoring Well *Onsite P17 Monitoring Well Onsite P3 Monitoring Well Onsite SP22 Monitoring Well Onsite SW-LR-2 Surface Water Offsite SW-LR-4 Surface Water Offsite SW-LR-6 Surface Water Offsite SW-LR-7 Surface Water Onsite SW-LR-8 Surface Water Onsite SW-LR-9 Surface Water Onsite A-1

Figure I Routine Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2007 A-2

APPENDIX B DATA TABLES

TABLE B-I.1 CONCENTRATIONS OF TRITIUM AND STRONTIUM-90 IN WELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2007 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 SR-90 MW-LR-1 05/02/07 < 162 MW-LR-1 10130/07 'C 178 < 1.8 MW-LR-2 05/01/07 < 164 MW-LR-2 10/31/07 <189

0.8 MW-LR-3 05/02/07

166 MW-LR-3 10/31/07

196 < 1.4 MW-LR-4 05/01/07

163 MW.LR-4 10/30/07 179 < 1.3 MW-LR-5 05102/07 309 +/- 117 MW-LR-5 11/01/07 281 +/- 125 < 0.8 MW-LR-5F 11/01/07 201 + 126 < 0.7 MW-LR-5 SPLIT 11/01/07 222 + 101 < 0.6 MW-LR-6 05/02/07 < 166 MW-LR-6 10/31/07 c 194 < 1.8 MW-L8-7 05/02107 < 163 MW-LR-7 10/30/07 191 < 1.3 MW-LR-8 05/03/07 281 +/- 114 MW-LR-8 10/30/07 < 188 < 1.0 MW-LR-8M 10/30107 215 +/- 128

1.2 MW-LR-8 SPLIT 10/30/07 < 175 < 0.5 MW-LR-9 05/03/07 308 +/- 117 MW-LR-9 DUP 05/03/07 209 : 112 MW-LR-9 10/30/07 269 +/- 131 < 1.3 MW-LR-9M 10/30/07 250 +/- 127 < 1.5 MW-LR-9 SPLIT 10/30/07 < 175 < 0.4 P-1Il 05/01107 < 163 P-1Il 10/30/07 < 194 < 1.6 P-14 05/03/07 < 165 P-14 10/30/07 < 196 < 1.3 P-16 05/03/07 < 167 P-16 DUP 05/03/07

164 P-16 10/30/07 213 +/- 122 < 1.7 P-17 05/01/07

164 P-17 10/30/07 < 199 < 1.4 P-3 05/01/07 < 158 P-3 10/31/07

194

1.6 SP-22 05/01/07

159 SP-22 10/30/07 < 194 < 0.8 SAMPLES ARE DISTILLED FOR H-3 ANALYSIS B-1

TABLE B-I.2 CONCENTRATIONS OF GAMMA EMITTERS INWELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2007 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA STC COLLECTION Be-7 K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 1-131 Cs-134 Cs-137 Ba-140 La-140 PERIOD MW-LR-1 10/30/07 < 44 < 92 <4 -c4 <c11 < 4 < 11 < 5 < 9 <c17 <5 < 5 < 35 <10 MW-LR-2 10/31/07 < 44 < 45 <4 <5 <10 <5 <11 <6 <9 <14 <5 <4 <36 '12 MW-LR-3 10/31/07 < 43 < 98 <5 <6 <10 <4 <9 <6 <8 <13 <4 <5 <29 <14 MW-LR-4 10/30/07 < 36 < 78 <4 <4 <8 <4 < 7 <4 <7 <12 <3 <4 <24 < 10 MW-LR-5 11/01/07 < 31 < 73 <3 <3 <8 <3 <7 <3 <7 <9 <3 '4 <24 <8 MW-LR-5F 11/01/07 < 41 < 36 <5 <5 < 11 <5 < 11 <6 < 10 < 14 <5 '5 <30 < 12 MW-LR-5 SPLIT 11/01/07 < 27 < 65 <2 <2 <4 <3 <7 <3 <6 <7 <3 <3 <11 <5 MW-LR-6 10/31/07 < 42 < 101 <5 <6 <12 <5 <11 <5 <10 <13 <5 <5 <35 <13 MW-LR-7 10/30/07 < 44 < 92 <5 <4 <11 <5 <9 <6 <8 <14 <4 <5 <33 <9 MW-LR-8 10/30/07 < 44 < 95 <5 <5 <12 <5 <9 6 <10 <15 <4 <5 <39 <12 MW-LR-8M 10/30/07 < 36 < 78 <4 <4 <9 <4 <7 <4 <7 '12 <3 <4 <29 <8 MW-LR-8 SPLIT 10/30/07 < 28 < 69 <3 <2 <3 <2 <5 <2 '4 <6 '2 <2 <11 '3 MW-LR-9 10/30/07 < 46 < 92 <5 <5 <10 <5 <13 <6 <10 <18 '5 <5 <41 <14 MW-LR-9M 10/30/07 < 31 < 36 <3 <4 <8 <4 <7 <4 <7 <11 <3 <4 <25 <9 MW-LR-9 SPLIT 10/30/07 < 28 < 76 <2 <3 <8. <1 <5 <4 <5 <8 <2 <3 <13 <3 P-11 10130/07 < 51 < 47 <5 <5 <11 <7 <11 <6 <10 <17 <4 <5 <35 <12 P-14 10/30/07 < 37 155 145 <4 < 4 <8 '3 <8 <4 <7 <12 '44 <4 <26 <8 P-16 10/30/07 < 27 < 28 <3 <3 < 7 <3 <7 <3 '6 <11 <3 <3 <24 -<7 P-17 10/30/07 < 30 < 31 <3 <3 <7 <4 <6 '4 <6 <11 <3 <3 <23 <7 P-3 10/31/07 < 35 < 70 <4 <4 < 9 <3 <7 '4 <7 <12 <4 <4 <29 <10 SP-22 10/30/07 < 25 < 53 < 3 < 3 < 6 <2 <5 <3 <5 < 9 <3 <3 <21 <7

TABLE B-1.1 CONCENTRATIONS OF TRITIUM AND STRONIUM-90 IN SURFACE WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION 2007 RESULTS IN UNITS OF PCI/LITER +/-2 SIGMA COLLECTION SITE DATE H-3 SR-90 SW-LR-2 4/30107

164 SW-LR-2 10129/07

197 < 0.7 SW-LR-4 10/29/07

195 SW-LR-6 10/29/07

194 SW-LR-7 4/30/07

166 SW-LR-7 10/30/07 < 181 < 1.5 SW-LR-8 10/31/07 < 192 SW-LR-9 10/31/07 < 191 SAMPLES ARE DISTILLED FOR H-3 ANALYSIS B-3

TABLE B-II.2 CONCENTRATIONS OF GAMMA EMITTERS IN SURFACE WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2007 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA STC COLLECTION Be-7 K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 1-131 Cs-134 Cs-137 Ba-140 La-140 PERIOD SW-LR-2 10/29/07 < 38 < 35 <4 <4 < 9 <4 <7 <5 < 7 < 14 <4 <4 < 31 < 10 SW-LR-7 10/30/07 < 34 < 74 < 4 <4 < 8 <4 <7 <4 <7 < 13 < 3 <4 < 28 <9

Docket No: 50-352 50 - 353 LIMERICK GENERATING STATION UNITS I and 2 Annual Radiological Groundwater Protection Program Report 1 January Through 31 December 2008 Prepared By Teledyne Brown Engineering Environmental Services Exel 6n.

Nuclear Limerick Generating Station Sanatoga, PA 19464 April 2009

Table Of Contents I. Sum mary and Conclusions ........................................................................................... I II. Introduction ........................................................................................................................ 2 A. Objectives of the RGPP ................................................................................... 2 B. Implementation of the Objectives ................................................................... 2 C. Program Description ........................................................................................ 3 D. Characteristics of Tritium (H-3) ......................................................................... 4 I1l. Program Description ................................................................................................... 4 A. Sam ple Analysis ................................................................................................ 4 B. Data Interpretation ........................................................................................... 5 C. Background Analysis ......................................................................................... 6

1. Background Concentrations of Tritium ........................... 6 IV. Results and Discussion ............................................................................................. 8 A. Groundwater Results ....................................................................................... 8 B. Surface Water Results ...................................................................................... 9 C. Drinking Water W ell Survey ............................................................................ 9 D. Summary of Results - Inter-laboratory Comparison Program ....................... 10 E. Leaks, Spills, and Releases ........................................................................... 10 F. Trends ............................................................................................................. 10 G. Investigations ................................................................................................ 10 H. Actions Taken................................................................................................ 10 V. References ...................................................................................................................... 11 i

Appendices Appendix A Location Designation Tables Table A-1 Radiological Groundwater Protection Program - Sampling Locations for the Limerick Generating Station, 2008 Figures Figure 1 Routine Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2008 Appendix B Data Tables Tables Table B-I.1 Concentrations of Tritium and Stronium-90 in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2008.

Table B-1.2 Concentrations of Gamma Emitters in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2008.

Table B-11.1 Concentrations of Tritium and Stronium-90 in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2008.

Table B-11.2 Concentrations of Gamma Emitters in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2008.

ii

I. Summary and Conclusions This report on the Radiological Groundwater Protection Program (RGPP) conducted for the Limerick Generating Station (LGS) by Exelon Nuclear covers the period 01 January 2008 through 31 December 2008. During that time period, 103 analyses were performed on 58 samples from 21 groundwater and surface water locations collected from the environment, both on and off station property in 2008.

There was one known release into the groundwater at Limerick Generating Station that occurred from a cooling tower overflow while a Radwaste discharge was in progress. The discharge was secured and no radioactivity was found in the water sample obtained.

Gamma-emitting radionuclides associated with licensed plant operations were not detected at concentrations greater than their respective Lower Limits of Detection (LLDs) as specified in the Offsite Dose Calculation Manual (ODCM) in any of the groundwater or surface water samples.

Strontium-90 was not detected at a concentration greater than the LLD of 2.0 picoCuries per liter (pCi/L) in any of the groundwater or surface water samples tested.

Tritium was not detected in any of the groundwater or surface water samples at concentrations greater than the United States Environmental Protection Agency (USEPA) drinking water standard (and the Nuclear Regulatory Commission Reporting Limit) of 20,000 pCi/L. Low levels of tritium were detected at concentrations greater than the LLD of 200 pCi/L in 5 of 15 groundwater monitoring locations and 1 of 6 surface water monitoring locations. The tritium concentrations ranged from 208 to 902 pCi/L. Although no drinking water pathway is available from groundwater, the dose via the drinking water pathway was calculated at 0.053 mrem to a child (total body), which was 0.89% of the 10 CFR 50, Appendix I dose limit.

In assessing all the data gathered for this report, it was concluded that the operation of Limerick Generating Station had no adverse radiological impact on the environment offsite of LGS.

1

II. Introduction The Limerick Generating Station (LGS), consisting of two 3458 MWt boiling water reactors owned and operated by Exelon Corporation, is located adjacent to the Schuylkill River in Montgomery County, Pennsylvania. Unit No. 1 went critical on 22 December 1984. Unit No. 2 went critical on 11 August 1989. The site is located in Piedmont countryside, transversed by numerous valleys containing small tributaries that feed into the Schuylkill River. On the eastern river bank elevation rises from approximately 110 to 300 feet mean sea level (MSL). On the western river bank elevation rises to approximately 50 feet MSL.

This report covers those analyses performed by Teledyne Brown Engineering (TBE) on samples collected in 2008.