Text

Annual Radiological Operating Report
	ML21113A017
Person / Time
Site:	Limerick
Issue date:	04/30/2021
From:	; Teledyne Brown Engineering Environmental Services
To:	; Office of Nuclear Reactor Regulation
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ML21113A015	List: LG-20-045, Annual Radiological Operating Report; LG-21-038, 2020 Annual Radiological Environmental Operating Report;
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	LG-20-045
	Download: ML21113A017 (126)
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Docket No: 50-352 50-353 LIMERICK GENERATING STATION UNITS 1 AND 2 Annual Radiological Environmental Operating Report 1 January through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services Limerick Power Station Pottstown, PA 19464 April 2021

Intentionally left blank Table of Contents I. Preface ............................................................................................................................ 1 II. Summary and Conclusions ............................................................................................. 8 III. Introduction................................................................................................................... 10 A. Objective of the REMP ...................................................................................... 10 B. Implementation of the Objectives ...................................................................... 10 IV. Program Description .................................................................................................... 11 A. Sample Collection .............................................................................................. 11 B. Sample Analysis ................................................................................................ 13 C. Data Interpretation ............................................................................................. 13 D. Program Exceptions .......................................................................................... 14 E. Program Changes ............................................................................................. 15 F. Compliance to 40 CFR 190 Limits ..................................................................... 15 V. Results and Discussion ................................................................................................ 17 A. Aquatic Environment ......................................................................................... 17

1. Surface Water ......................................................................................... 17

2. Drinking Water ........................................................................................ 17

3. Fish ......................................................................................................... 18

4. Sediment ................................................................................................. 18 B. Atmospheric Environment ................................................................................. 18

1. Airborne .................................................................................................. 18

a. Air Particulates ............................................................................. 18

b. Airborne Iodine............................................................................. 19

2. Terrestrial ................................................................................................ 19

a. Milk............................................................................................... 19

b. Broad Leaf Vegetation ................................................................. 20 C. Ambient Gamma Radiation ............................................................................... 20 D. 10 CFR 20.2002 Permit Storage Area .............................................................. 21 E. Independent Spent Fuel Storage Area .............................................................. 21 F. Land Use Survey ............................................................................................... 21 G. Summary of Results - Inter-Laboratory Comparison Program ......................... 22

1. TBE Laboratory Results .......................................................................... 23

2. EIS Laboratory Results ........................................................................... 24

3. GEL Laboratory Results.......................................................................... 25 VI. References .................................................................................................................. 26

Appendices Appendix A Radiological Environmental Monitoring Report Summary Tables Table A-1 Radiological Environmental Monitoring Program Annual Summary for the Limerick Generating Station, 2020 Appendix B Location Designation, Distance & Direction, and Sample Collection &

Analytical Methods Tables Table B-1 Location Designation and Identification System for the Limerick Generating Station Table B-2 Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Limerick Generating Station, 2020 Table B-3 Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Limerick Generating Station, 2020 Figures Figure B-1 Environmental Sampling Locations Within 5,280 Feet of the Limerick Generating Station, 2020 Figure B-2 Environmental Sampling Locations Between 5,280 and 26,400 Feet from the Limerick Generating Station, 2020 Figure B-3 Environmental Sampling Locations Greater Than 26,400 Feet from the Limerick Generating Station, 2020 Appendix C Data Tables and Figures - Primary Laboratory Tables Table C-I.1 Concentrations of Tritium in Surface Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-I.2 Concentrations of I-131 in Surface Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-I.3 Concentrations of Gamma Emitters in Surface Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-II.1 Concentrations of Gross Beta in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-II.2 Concentrations of Tritium in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-II.3 Concentrations of I-131 in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-II.4 Concentrations of Gamma Emitters in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020

Table C-III.1 Concentrations of Gamma Emitters in Predator and Bottom Feeder (Fish) Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-IV.1 Concentrations of Gamma Emitters in Sediment Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-V.1 Concentrations of Gross Beta in Air Particulate Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-V.2 Monthly and Yearly Mean Values of Gross Beta Concentrations in Air Particulate Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-V.3 Concentrations of Gamma Emitters in Air Particulate Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-VI.1 Concentrations of I-131 in Air Iodine Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-VII.1 Concentrations of I-131 in Milk Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-VII.2 Concentrations of Gamma Emitters in Milk Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-VIII.1 Concentrations of Gamma Emitters in Broad Leafy Vegetation Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table C-IX.1 Quarterly DLR Results for Limerick Generating Station, 2020 Figures Figure C-1 Mean Monthly Total Gross Beta Concentrations in Drinking Water Samples Collected in the Vicinity of LGS, 1982 - 2020 Figure C-2 Mean Monthly Gross Beta Concentrations in Air Particulate Samples Collected in the Vicinity of LGS, 1982 - 2020 Figure C-3 Mean Weekly Gross Beta Concentrations in Air Particulate Samples Collected in the Vicinity of LGS, 2020 Appendix D Data Tables and Figures - Comparison Laboratory Tables Table D-I.1 Concentrations of Total Gross Beta in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table D-I.2 Concentrations of I-131 in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table D-I.3 Concentrations of Tritium in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table D-I.4 Concentrations of Gamma Emitters in Drinking Water Samples Collected in the Vicinity of Limerick Generating Station, 2020

Table D-II.1 Concentrations of Gross Beta in Air Particulate and I-131 in Air Iodine Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table D-II.2 Concentrations of Gamma Emitters in Air Particulate Samples Collected in the Vicinity of Limerick Generating Station, 2020 Table D-III.1 Concentrations of I-131 by Chemical Separation and Gamma Emitters in Milk Samples Collected in the Vicinity of Limerick Generating Station, 2020 Figures Figure D-1 Comparison of Monthly Total Gross Beta Concentrations in Drinking Water Samples Split Between EIS and TBE, 2020 Figure D-2 Comparison of Weekly Gross Beta Concentrations in Air Particulate Samples Collected from LGS Collocated Locations 11S1 and 11S2, 2020 Appendix E Inter-Laboratory Comparison Program Tables Table E-1 Analytics Environmental Radioactivity Cross Check Program Teledyne Brown Engineering, 2020 Table E-2 DOEs Mixed Analyte Performance Evaluation Program (MAPEP)

Teledyne Brown Engineering, 2020 Table E-3 ERA Environmental Radioactivity Cross Check Program Teledyne Brown Engineering, 2020 Table E-4 Analytics Environmental Radioactivity Cross Check Program Exelon Industrial Services, 2020 Table E-5 ERA Environmental Radioactivity Cross Check Program Exelon Industrial Services, 2020 Table E-6 DOEs Mixed Analyte Performance Evaluation Program (MAPEP)

GEL Laboratories, 2020 Table E-7 ERA Environmental Radioactivity Cross Check Program GEL Laboratories, 2020 Table E-8 Analytics Environmental Radioactivity Cross Check Program GEL Laboratories, 2020 Appendix F Errata Data Appendix G Annual Radiological Groundwater Protection Program Report (ARGPPR)

I. Preface The following sections of the preface are meant to help define key concepts, provide clarity, and give context to the readers of this report.

Annual Reports The Nuclear Regulatory Commission (NRC) is the federal agency who has the role to protect public health and safety related to nuclear energy. Nuclear Power Plants have made many commitments to the NRC to ensure the safety of the public. As part of these commitments, they provide two reports annually to specifically address how the stations operation impacts the environment of the local communities. The NRC then reviews these reports and makes them available to the public. The names of the reports are the Annual Radioactive Effluent Release Report (ARERR) and the Annual Radiological Environmental Operating Report (AREOR).

The ARERR reports the results of the analyses of samples taken from the effluent release paths at the station. An effluent is a liquid or gaseous waste, containing plant-related radioactive material emitted at the boundary of the facility.

The AREOR reports the results of the analyses of samples obtained in the environment surrounding the station. Environmental samples include air, water, vegetation, and other sample types that are identified as potential pathways radioactivity can reach humans.

Graphic 1. Examples of Gaseous and Liquid Effluent Pathways Graphic 1 demonstrates some potential exposure pathways from Limerick Generating Station. The ARERR and AREOR together ensure Nuclear Power Plants are operating in a manner that is within established regulatory commitments meant to adequately protect the public.

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Understanding Radiation Generally radiation is defined as emitted energy in the form of waves or particles. If radiation has enough energy to displace electrons from an atom it is termed ionizing, otherwise it is non-ionizing. Non-Ionizing radiation includes light, heat given off from a stove, radiowaves and microwaves. Ionizing radiation occurs in atoms, particles too small for the eye to see. So, what are atoms and how does radiation come from them?

Graphic 2. Types of Radiation, from NASA Hubblesite An atom is the smallest part of an element that maintains the characteristics of that element. Atoms are made up of three parts: protons, neutrons, and electrons.

Graphic 3. Structure of an Atom The number of protons in an atom determines the element. For example, a hydrogen atom will always have one proton while an oxygen atom will always have eight protons. The protons are clustered with the neutrons forming the nucleus at the center of the atom. Orbiting around the nucleus are the relatively small electrons.

Isotopes are atoms that have the same number of protons but different numbers of neutrons. Different isotopes of an element will all have the same chemical properties and many isotopes are radioactive while other isotopes are not radioactive. A radioactive isotope can emit radiation because it contains excess energy in its nucleus. Radioactive atoms and isotopes are also referred to as 2

radionuclides and radioisotopes.

There are two basic ways that radionuclides are produced at a nuclear power plant.

The first is fission, which creates radionucides that are called fission products.

Fission occurs when a very large atom, such as uranium-235 (U-235) or plutonium-239 (Pu-239), absorbs a neutron into its nucleus making the atom unstable. The unstable atom can then split into smaller atoms. When fission occurs there is a large amount of energy released in the form of heat. A nuclear power plant uses the heat generated to boil water that spins turbines to produce electricity.

The second way a radionuclide is produced at a nuclear power plant is through a process called activation and the radionuclides produced in this method are termed activation products. Pure water that passes over the fissioning atoms is used to cool the reactor and also produce steam to turn the turbines. Although this water is considered to be very pure, there are always some contaminants within the water from material used in the plants construction and operation. These contaminants are exposed to the fission process and may become activation products. The atoms in the water itself can also become activated and create radionuclides.

Over time, radioactive atoms will reach a stable state and no longer be radioactive.

To do this they must release their excess energy. This release of excess energy is called radioactive decay. The time it takes for a radionuclide to become stable is measured in units called half-lives. A half-life is the amount of time it takes for half of the original radioactivity to decay. Each radionuclide has a specific half-life.

Some half-lives can be very long and measured in years while others may be very short and measured in seconds.

Graphic 4. Radioactive Decay Half-Life In the annual reports you will see both man made and naturally ocurring radionuclides listed, for example potassium-40 (K-40, natural) and cobalt-60 (Co-60, man-made). We are mostly concerned about man-made radionuclides because they can be produced as by-products when generating electricity at a nuclear power plant. It is important to note that there are also other ways man-made radionuclides are produced, such as detonating nuclear weapons. Weapons 3

testing has deposited some of the same man-made radionuclides into the environment as those generated by nuclear power, and some are still present today because of long half-lives.

Measuring Radiation There are four different but interrelated units for measuring radioactivity, exposure, absorbed dose, and dose equivalent. Together, they are used to scientifically report the amount of radiation and its effects on humans.

x Radioactivity refers to the amount of ionizing radiation released by a material.

The units of measure for radioactivity used within the AREOR and ARERR are the Curie (Ci). Small fractions of the Ci often have a prefix, such as the PLFUR&XULH &L ZKLFKPHDQVRID&XULH

x Exposure describes the amount of radiation traveling through the air. The units of measure for exposure used within the AREOR and ARERR are the Roentgen (R). Traditionally direct radiation monitors placed around the site are measured milliRoentgen (mR), RIRQH5

x Absorbed dose describes the amount of radiation absorbed by an object or person. The units of measure for absorbed dose used within the AREOR and ARERR are the rad. Noble gas air doses are reported by the site are measured in millirad PUDG RIRQHUDG

x Dose equivalent (or effective dose) combines the amount of radiation absorbed and the health effects of that type of radiation. The units used within the AREOR and ARERR are the Roentgen equivalent man (rem).

Regulations require doses to the whole body, specific organ, and direct UDGLDWLRQWREHUHSRUWHGLQPLOOLUHP PUHP RIRQHUHP

4

Sources of Radiation People are exposed to radiation every day of their lives and have been since the dawn of mankind. Some of this radiation is naturally occurring while some is man-made. There are many factors that will determine the amount of radiation individuals will be exposed to such as where they live, medical treatments, etc. The average person in the United States is exposed to approximately 620 mrem each year. 310 mrem comes from natural sources and 310 from man-made sources. The Graphic 5 shows what the typical sources of radiation are for an individual over a calendar year:

Graphic 5. Sources of Radiation Exposure in the U.S., from NCRP Report No. 160 The radiation from a nuclear power plant is included in the chart as part of the Industrial and Occupational fraction, <0.1%. The largest natural source of radiation is from radon, because radon gas travels in the air we breathe. Perhaps you know someone who had a CT scan at a hospital to check his or her bones, brain, or heart.

CT scans are included in the chart as Medical Procedures, which make up the next largest fraction. Graphic 6 on the following page shows some of the common doses humans receive from radiation every year.

5

Graphic 6 .Relative Doses from Radiation Sources, from EPA Radiation Doses and Sources 6

Radiation Risk Current science suggests there is some risk from any exposure to radiation.

However, it is very hard to tell whether cancers or deaths can be attributed to very low doses of radiation or by something else. U.S. radiation protection standards are based on the premise that any radiation exposure carries some risk.

The following graph is an example of one study that tries to relate risk from many different factors. This graph represents risk as Days of Lost Life Expectancy. All the categories are averaged over the entire population except Male Smokers, Female Smokers, and individuals that are overweight. Those risks are only for people that fall into those categories. The category for Nuclear Power is a government estimate based on all radioactivity releases from nuclear power, including accidents and wastes.

Graphic 7. Days of Lost Life Expectancy, Adapted from the Journal of American Physicians and Surgeons Volume 8 Number 2 Summer 2003 7

II. Summary and Conclusions In 2020, the Limerick Generating Station released to the environment through the radioactive effluent liquid and gaseous pathways approximately 96 curies of noble gas, fission and activation products and approximately 36 curies of tritium. The dose from both liquid and gaseous effluents was conservatively calculated for the Maximum Exposed Member of the Public. The results of those calculations and their comparison to the allowable limits were as follows:

Gaseous and Liquid Radiation Doses to Members of the Public at the Highest Dose Receptor

% of Estimated Age Maximum Individual Noble Gas Applicable Dose Applicable Limit Unit Dose Group Limit Nearest Residence Gamma Air Dose 2.66E-03 All 1.33E-02 20 mRad Nearest Residence Beta Air Dose 2.13E-03 All 5.33E-03 40 mRad Nearest Residence Total Body 2.52E-03 All 2.52E-02 10 mrem Nearest Residence Skin 4.39E-03 All 1.46E-02 30 mrem Iodine, Particulate, C-14 & Tritium Vegetation Pathway Bone 1.33E+00 Child 4.42E+00 30 mrem Liquid LGS Outfall Total Body 2.83E-04 Adult 4.71E-03 6 mrem LGS Outfall Liver 2.34E-03 Teen 1.17E-02 20 mrem The calculated doses, from the radiological effluents released from Limerick, were a very small percentage of the allowable limits.

This report on the Radiological Environmental Monitoring Program conducted for the Limerick Generating Station (LGS) by Exelon covers the period 1 January 2020 through 31 December 2020. During that time period, 1,488 analyses were performed on 1,244 samples.

Surface and drinking water samples were analyzed for concentrations of tritium (H-3), low level iodine-131 (I-131) and gamma-emitting nuclides. Drinking water samples were also analyzed for concentrations of total gross beta. Total gross beta activities detected were consistent with those detected in previous years. No other fission or activation products were detected.

Fish (predator and bottom feeder) samples were analyzed for concentrations of gamma-emitting nuclides. Concentrations of naturally-occurring potassium-40 (K-40) were consistent with those detected in previous years. No fission or activation products were detected in fish.

Sediment samples were analyzed for concentrations of gamma-emitting nuclides.

No station-produced fission or activation products were found in sediment. For results, discussion, and dose to member of the public calculation see Section IV.F.1.

Air particulate samples were analyzed for concentrations of gross beta and gamma-emitting nuclides. Gross beta and cosmogenic, naturally-occurring beryllium-7 (Be-7) were detected at levels consistent with those detected in previous years. No fission or activation products were detected.

8

High-sensitivity I-131 analyses were performed on weekly air samples. All results were less than the minimum detectable concentration.

The air monitoring systems employed in the nuclear industry have proven to be capable of detecting very low levels of activity in the atmosphere, as activity from both the Chernobyl and Fukushima events was detected at many of the worlds nuclear power plants, including Limerick Generating Station.

Cow milk samples were analyzed for concentrations of I-131 and gamma-emitting nuclides. Concentrations of naturally-occurring K-40 were consistent with those detected in previous years. No fission or activation products were found.

Broadleaf vegetation samples were analyzed for gamma-emitting nuclides. Only naturally-occurring activity was detected. K-40 was detected in all samples. Be-7 was found in 16 of 32 samples. Radium-226 (Ra-226) was found in 2 of 32 samples.

Thorium-228 (Th-228) was found in 18 of 32 samples. No activity due to plant operations were detected.

Review of the gamma spectroscopy results from the surface water samples located at the Limerick intake (24S1) and downstream of the 10 CFR 20.2002 permitted storage area showed no evidence of offsite radionuclide transport from the 2002 permitted storage area.

Environmental ambient gamma radiation measurements were performed quarterly using Dosimeters of Legal Record (DLR). Levels detected were consistent with those observed in previous years and no facility-related dose was detected. A review of the dosimetry data for the nearest residence to the Independent Spent Fuel Storage Installation (ISFSI) indicates no direct dose was received.

A Radiological Groundwater Protection Program (RGPP) was established in 2006 as part of an Exelon Nuclear fleetwide assessment of potential groundwater intrusion from the operation of the Station. Results and Discussion of groundwater samples are covered in Appendix G.

In assessing the data gathered for this report and comparing these results with preoperational data, it was concluded that the operation of LGS had no adverse radiological impact on the environment.

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III. Introduction The Limerick Generating Station (LGS), consisting of two 3,515 MW 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 riverbank, elevation rises from approximately 110 to 300 feet mean sea level (MSL). On the western riverbank elevation rises to approximately 50 feet MSL to the western site boundary.

A Radiological Environmental Monitoring Program (REMP) for LGS was initiated in 1971. Review of the 1971 through 1977 REMP data resulted in the modification of the program to comply with changes in the Environmental Report Operating License Stage (EROL) and the Branch Technical Position Paper (Rev. 1, 1979). The preoperational period for most media covers the periods 1 January 1982 through 21 December 1984 and was summarized in a separate report. This report covers those analyses performed by Teledyne Brown Engineering (TBE), Mirion Technologies, DQG([HORQ,QGXVWULDO6HUYLFHV (,6 *(//DERUDWRULHV *(/ RQVDPSOHVFROOHcted during the period 1 January 2020 through 31 December 2020.

On 6 July 1996, a 10 CFR 20.2002 permit was issued to Limerick for storage of slightly contaminated soils, sediments and sludges obtained from the holding pond, cooling tower and spray pond systems. These materials will decay to background while in storage. Final disposition will be determined at Station decommissioning.

On 21 July 2008, an ISFSI pad was put into service. The ISFSI is dry cask storage, where spent nuclear fuel is stored.

A. Objective of the REMP The objectives of the REMP are to:

1. Provide data on measurable levels of radiation and radioactive materials in the site environs;

2. Validate the radioactive effluent control program by evaluating the relationship between quantities of radioactive material released from the plant and resultant radiation doses to individuals from principal pathways of exposure.

B. Implementation of the Objectives The implementation of the objectives is accomplished by:

1. Identifying significant exposure pathways

2. Establishing baseline radiological data of media within those pathways

3. Continuously monitoring those media before and during station operation to assess station radiological effects (if any) on man and the environment 10

IV. Program Description A. Sample Collection Samples for the LGS REMP were collected for Exelon Nuclear by Exelon Industrial Services (EIS) and Normandeau Associates, Inc. (NAI). This section describes the general collection methods used to obtain environmental samples for the LGS REMP in 2020. Sample locations and descriptions can be found in Tables B-1 and B-2, and Figures B-1 through B-3, Appendix B. The collection procedures used by EIS are listed in Table B-3. Control locations are sample locations that are not expected to be impacted by plant operations and are used to determine a baseline in the environment for each type of sample.

Aquatic Environment The aquatic environment was evaluated by performing radiological analyses on samples of surface water, drinking water, fish, and sediment. Two-gallon water samples were collected monthly from composite samplers located at two surface water locations (13B1 and 24S1) and four drinking water locations (15F4, 15F7, 16C2, and 28F3). Control locations were 24S1, and 28F3. All samples were collected in new unused plastic bottles, which were rinsed at least twice with source water prior to collection. Fish samples comprising of the flesh of two groups, bottom feeder &DUS1RUWKHUQ

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UHHQ6XQILVK6PDOOPRXWK%DVV<HOORZ3HUFK), were collected semiannually at two locations, 16C5 and 29C1 (control). Sediment samples composed of recently deposited substrate were collected at three locations semiannually, 16B2, 16C4, and 33A2 (control).

Atmospheric Environment The atmospheric environment was evaluated by performing radiological analyses on samples of air particulate, airborne iodine, and milk. Airborne iodine and particulate samples were collected and analyzed weekly at seven locations (6C1, 10S3, 11S1, 13S4, 14S1, 15D1, and 22G1). The control location was 22G1. Airborne iodine and particulate samples were obtained at each location, using a vacuum pump with charcoal and glass fiber filters attached. The pumps were run continuously and sampled air at the rate of approximately one cubic foot per minute. The filters were replaced weekly and sent to the laboratory for analysis.

Terrestrial Environment Milk samples were collected biweekly at four locations (18E1, 19B1, 23F1, and 25C1) from April through November, and monthly from December through March. Location 23F1 was the control. All samples were collected in new unused two gallon plastic bottles from the bulk tank at each location, preserved with sodium bisulfite, and shipped promptly to the laboratory.

11

Broadleaf vegetation was collected monthly, during the growing season, at three locations (11S3, 13S3, and 31G1). The control location was 31G1.

Twelve different kinds of vegetation samples were collected and placed in new unused plastic bags and sent to the laboratory for analysis.

Ambient Gamma Radiation Direct Radiation measurements were made using thermoluminescent dosimeters. The DLR locations were placed on and around the LGS site as follows:

A site boundary ring consisting of 16 locations (36S2, 3S1, 5S1, 7S1, 10S3, 11S1, 13S2, 14S1, 18S2, 21S2, 23S2, 25S2, 26S3, 29S1, 31S1, and 34S2) near and within the site perimeter representing fence post doses (i.e., at locations where the doses will be potentially greater than maximum annual off-site doses) from LGS releases.

An intermediate distance ring consisting of 16 locations (36D1, 2E1, 4E1, 7E1, 10E1, 10F3, 13E1, 16F1, 19D1, 20F1, 24D1, 25D1, 28D2, 29E1, 31D2, and 34E1) extending to approximately 5 miles from the site designed to measure possible exposures to close-in population.

The balance of eight locations (5H1, 6C1, 9C1, 13C1, 15D1, 17B1, 20D1, and 31D1) representing control and special interest areas such as population centers, schools, etc.

The specific dosimetry locations were determined by the following criteria:

1. The presence of relatively dense population;

2. Site meteorological data taking into account distance and elevation for each of the sixteen-GHJUHHVHFWRUVDURXQGWKHVLWHZKHUH

estimated annual dose from LGS, if any, would be most significant;

3. On hills free from local obstructions and within sight of the vents (where practical);

4. And near the closest dwelling to the vents in the prevailing downwind direction.

Two dosimeters were placed at each location in a mesh basket tube located approximately three feet above ground level. The dosimeters were exchanged quarterly and sent to Mirion Technologies for analysis.

10 CFR 20.2002 Permit Storage Area In 1996, the Limerick Generating Station received NRC approval to store slightly contaminated soils, sludges, and sediments on site per the requirements of 10 CFR 20.2002. These materials will be stored until end of the site's renewed operating license. At that time the material will be evaluated along with the site for decommissioning. The area is approximately 1.5 acres in size and was evaluated to hold a maximum of 1.12E+06 cubic 12

feet with no more than 7E+04 cubic feet added to the area in any single year.

After each material placement on the storage area, the area is graded and seeded to prevent erosion. Since all groundwater movement is to the river, the use of the REMP surface water sampling program is used as a check on potential groundwater movement from the pad. In 2020, 0 cubic feet of cooling water sludge was placed on the permitted storage area.

Independent Spent Fuel Storage Installation (ISFSI)

The results from the dosimeter locations 36S2 and 3S1 were used to determine the direct radiation exposure to the nearest residence from the ISFSI pad.

B. Sample Analysis This section lists the analyses performed by the primary laboratory, Teledyne Brown Engineering (TBE), the secondary laboratories, Exelon Industrial Services, LLC (EIS) and GEL Laboratories, LLC (GEL) and also Mirion Technologies on environmental samples for the LGS REMP in 2020. The analytical procedures used by the laboratories are listed in Appendix B Table B-3. Analysis results from TBE are provided in Appendix C. Analysis results from EIS and GEL Laboratories are provided in Appendix D of this report.

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

1. Concentrations of beta emitters in drinking water and air particulates

2. Concentrations of gamma emitters in surface and drinking water, air particulates, milk, fish, broad leaf vegetation, and sediment

3. Concentrations of tritium in surface and drinking water

4. Concentrations of I-131 in air, milk, and drinking water

5. Ambient gamma radiation levels at various site environs C. Data Interpretation The radiological and direct radiation data collected prior to LGS becoming operational was used as a baseline with which these operational data were compared. For the purpose of this report, LGS was considered operational at initial criticality. In addition, data were compared to previous years' operational data for consistency and trending. 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 13

is intended as a before the fact estimate of a system (including instrumentation, procedure and sample type) and not as an after the fact criteria for the presence of activity. All analyses are designed to achieve the required LGS detection limits for environmental sample analysis.

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

2. Net Activity Calculation and Reporting of Results Net activity for a sample was calculated by subtracting background activity from the sample activity. Since the REMP measures extremely small changes in radioactivity in the environment, background variations may result in sample activity being lower than the background activity affecting a negative number. An MDC was reported in all cases where positive activity was not detected.

Gamma spectroscopy analyzes samples for the full range of nuclides. All nuclides that identified positive results are reported. Each type of sample also looks for specific nuclides and the results for each type of sample were reported as follows:

For surface and drinking water, 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 were reported For broadleaf vegetation, eleven nuclides, Be-7, K-40, Mn-54, Co-58, Co-60, I-131, Cs-134, Cs-137, Ra-226, Th-228, and Th-232 were reported For fish, nine nuclides, K-40, Mn-54, Co-58, Fe-59, Co-60, Zn-65, I-131, Cs-134, and Cs-137 were reported For sediment, eight nuclides, Be-7, K-40, Mn-54, Co-58, Co-60, I-131, Cs-134, and Cs-137 were reported For air particulates, six nuclides, Be-7, Mn-54, Co-58, Co-60, Cs-134, and Cs-137 were reported For milk, five nuclides, K-40, Cs-134, Cs-137, Ba-140, and La-140 were reported Means and standard deviations of positive results were calculated. The standard deviations represent the variability of measured results for different samples rather than single analysis uncertainty.

D. Program Exceptions For 2020 the LGS REMP had a sample recovery rate of greater than 99%.

Exceptions are listed below:

14

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sample station. It was determined that the breaker on the pole supplying power to the sample station had tripped during a severe storm.

(IR 4360178)

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ZHUHQRWDYDLODEOHGXHWRZRUNEHLQJSHUIRUPHGE\3(&2

Once it was discovered that PECO was performing work that removed the power from the station location, PECO was contacted, and power was restored. (IR 4386138)

3. When the air particulate sample from location 11S1 was pulled on

LWZDVQRWLFHGE\WKH([HORQ,QGXVWULDO6HUYLFHV (,6

technician that the filter loading appeared to be light in comparison to previous samples and in comparison with the particulate sample from 11S2 which is co-located with 11S1. The EIS technician verified the flow roto-meter was reading within the expected range. When the particulate filter for 11S1 was pulled the following week, it again appeared to have light loading. The EIS technician examined the sample pump and determined the muffler was loose on the sample pump. The following week, the loading appeared to return to normal. Though the sample pump vendor states that a loose muffler will not impact filter loading, a corrective action to inspect all sample pump mufflers weekly was implemented.

(IR 4370772)

Each program exception was reviewed to understand the causes of the program exception. Occasional equipment breakdowns were unavoidable.

The overall sample recovery rate indicates that the appropriate procedures and equipment are in place to assure reliable program implementation.

E. Program Changes There were no program changes to the ODCM in 2020.

F. Compliance to 40 CFR 190 Limits

1. Dose to Members of the Public at or Beyond Site Boundary Per the ODCM Control 6.2, the Annual Radioactive Effluent Release Report shall include an assessment of the radiation doses to the hypothetically highest exposed MEMBER OF THE PUBLIC from reactor releases and other nearby uranium fuel cycle sources. The ODCM does not require population doses to be calculated. For purposes of this calculation the following assumptions were made:

x Long term annual DYHUDJHPHWHRURORJ\;4DQG'4DQG actual gaseous effluent releases were used.

15

x Gamma air dose, Beta air dose, Total Body and Skin doses were attributed to noble gas releases.

x Critical organ and age group dose attributed to iodine, particulate, Carbon-14 and tritium releases.

x 100 percent occupancy factor was assumed.

x Dosimetry measurements obtained from the REMP for the nearest residence to the Independent Spent Fuel Storage Installation (ISFSI) was used to determine direct radiation exposure.

x The highest doses from the critical organ and critical age group for each release pathway was summed and added to the net dosimetry measurement from nearest residence to the ISFSI for 40 CFR 190 compliance.

40 CFR 190 Compliance:

The maximum calculated dose to a real individual would not exceed 0.27 mRem (total body), 1.33 mRem (organ), or 0.2 mRem (thyroid).

All doses calculated were below all ODCM and 40 CFR Part 190 limits to a real individual.

Table 1: 40 CFR 190 Compliance Gaseous Effluents

% of Particulate, Liquid Net Direct Noble Total Applicable Limit Unit Iodine, C-14 Effluents Radiation Limit Gas

& Tritium Total Body Dose 2.52E-03 2.66E-01 2.83E-04 0.00E+00 2.69E-01 1.08E+00 25 mRem Organ Dose 4.39E-03 1.33E+00 2.34E-03 0.00E+00 1.33E+00 5.33E+00 25 mRem Thyroid Dose 2.13E-03 2.76E-01 2.28E-04 0.00E+00 2.78E-01 3.71E-01 75 mRem 16

V. Results and Discussion A. Aquatic Environment

1. Surface Water Samples were taken from a continuous sampler at two locations (13B1 and 24S1) on a monthly schedule. Of these locations only 13B1 located downstream, could be affected by Limericks effluent releases. The following analyses were performed:

Tritium Monthly samples from all locations were composited quarterly and analyzed for tritium activity (Appendix C, Table C-I.1). All results were below the required LLD.

Iodine-131 Monthly samples were taken from location 24S1 and analyzed for low-level I-131 activity (Appendix C, Table C-I.2). All results were below the required LLD.

Gamma Spectrometry Samples from all locations were analyzed for gamma-emitting nuclides (Appendix C, Table C-I.3). All nuclides were below the required LLDs.

2. Drinking Water Monthly samples were collected from continuous water samplers at four locations (15F4, 15F7, 16C2, and 28F3). Three locations (15F4, 15F7, and 16C2) could be affected by Limericks effluent releases. The following analyses were performed:

Gross Beta Samples from all locations were analyzed for concentrations of total gross beta (Appendix C, Tables C-II.1). The values ranged from 2.2 to

S&L/DQGWRWDOJURVVEHWDZDVGHWHFWHGDWDOOVDPSOHORFDWLRQV

Concentrations detected were consistent with those detected in previous years (Appendix C, Figure C-1).

Tritium Monthly samples from all locations were composited quarterly and analyzed for tritium activity. All results were below required LLD (Appendix C, Table C-II.2).

17

Iodine-131 Monthly samples were taken from all locations and analyzed for I-131 activity (Appendix C, Table C-II.3). All results were below the required LLD.

Gamma Spectrometry Samples from all locations were analyzed for gamma-emitting nuclides (Appendix C, Table C-II.4). All results were below the required LLDs.

3. Fish Fish samples comprised of bottom feeder &DUS1RUWKHUQ+RJVXFNHU

1RUWKHU6XFNHU:KLWH6XFNHU) and SUHGDWRU $PHULFDQ(HO%ODFN

&UDSSLH%OXHJLOO%URZQ7URXW&KDQQHO&DWILVK)ODWKHDG&DWILVK

UHHQ6XQILVK6PDOOPRXWK%DVV<HOORZ3HUFK were collected at two locations (16C5 and 29C1) in the spring and fall season. Location 16C5 could be affected by Limericks effluent releases. The following analysis was performed:

Gamma Spectrometry The edible portion of fish samples from both locations was analyzed for gamma-emitting nuclides (Appendix C, Table C-III.1). Naturally-occurring K-40 was fouQGDWDOOVWDWLRQVDQGUDQJHGIURPWRS&LNJZHW

and was consistent with levels detected in previous years. No other activity was detected and the required LLD was met.

4. Sediment Aquatic sediment samples were collected at three locations (16B2, 16C4 and 33A2) semiannually. Two of these locations (16B2 and 16C4) could be affected by Limericks effluent releases. The following analysis was performed:

Gamma Spectrometry Sediment samples from all three locations were analyzed for gamma-emitting nuclides (Appendix C, Table C-IV.1). Nuclides detected were naturally-occurring Be-7 and K-40.

Be-ZDVIRXQGDWRQHORFDWLRQDWDFRQFHQWUDWLRQRIS&LNJGU\

K-40 was found at all locations and ranged from 10,650 to 14,520 S&LNJ

dry. No other activity was detected and the require LLD was met.

B. Atmospheric Environment

1. Airborne

a. Air Particulates Continuous air particulate samples were collected from seven 18

locations on a weekly basis. The seven locations were separated into three groups: Group I represents locations within the LGS site boundary (10S3, 11S1, 13S4, and 14S1), Group II represents the locations at an intermediate distance from the LGS site (6C1 and 15D1), and Group III represents the control location at a remote distance from LGS (22G1). The following analyses were performed:

Gross Beta Weekly samples were analyzed for concentrations of beta emitters (Appendix C, Table C-V.1 and C-V.2). Detectable gross beta activity was observed at all locations as expected. The results from the on-site locations (Group I) ranged from 4E-03 to 29E-S&LP3 with a mean of 13E-S&LP3. The results from the intermediate distance location (Group II) ranged from 5E-03 to 30E-S&LP3 with a mean of 13E-S&LP3. The results from the remote distance locations (Group III) ranged from 6E-03 to 29E-S&LP3 with a mean of 13E-S&LP3. Comparison of the 2020 air particulate data with previous years data indicates no effects from the operation of LGS (Appendix C, Figure C-2). In addition, a comparison of the weekly mean values for 2020 indicates no notable differences among the three groups. (Appendix C, Figure C-3).

Gamma Spectrometry Weekly samples were composited quarterly and analyzed for gamma-emitting nuclides. Naturally-occurring Be-7 was detected in all 28 samples and is attributed to cosmic ray activity (cosmogenic).

These values ranged from 48E-03 to 93E-S&LP3. All other nuclides were below the required LLDs. (Appendix C, Table C-V.3)

b. Airborne Iodine Continuous air samples were collected from seven locations (6C1, 10S3, 11S1, 13S4, 14S1, 15D1, and 22G1) and analyzed weekly for I-131. All results were below the required LLD.

(Appendix C, Table C-VI.1)

2. Terrestrial

a. Milk Samples were collected from four locations (18E1, 19B1, 23F1, and 25C1) biweekly April through November and monthly December through March. The following analyses were performed:

19

Iodine-131 Milk samples from all locations were analyzed for concentrations of I-131. All results were below the required LLD.

(Appendix C, Table C-VII.1)

Gamma Spectrometry Each milk sample was analyzed for concentrations of gamma-emitting nuclides (Appendix C, Table C-VII.2).

Naturally-occurring K-40 activity was found in all samples and ranged IURPWRS&L/$OORWKHUQXFOLGHVZHUHEHORZWKHUHTXLUHG

LLDs.

b. Broadleaf Vegetation Eleven types of broadleaf vegetation samples were collected from three locations (11S3, 13S3, and 31G1) monthly from June through September. The following analysis was performed:

Gamma Spectrometry Each broadleaf vegetation sample was analyzed for concentrations of gamma-emitting nuclides (Appendix C, Table C-VIII.1). Cosmogenic, naturally-occurring Be-7 was found in 16 of 32 samples and ranged IURPWRS&LNJZHW1DWXUDOO\-occurring K-40 was found in all VDPSOHVDQGUDQJHGIURPWRS&LNJZHW1DWXUDOO\-

occurring Ra-226 was found in 2 of 32 samples and ranged from 1,084 WRS&LNJZHW1DWXUDOO\-occurring Th-228 was found in 18 of 32 VDPSOHVDQGUDQJHGIURPWRS&LNJwet. All other nuclides were below the required LLDs.

C. Ambient Gamma Radiation Ambient gamma radiation levels were measured utilizing Panasonic 814 (CaSO4) thermoluminescent dosimeters. Forty dosimeter locations were established around the site. Results of dosimeter measurements are listed in Appendix C, Table C-IX.1. Dosimeter measurements were reported in P5VWDQGDUGPRQWK$OOGRVLPHWHUPHDVXUHPHQWVZHUHEHORZ

P5VWDQGDUGPRQWKZLWKDUDQJHRIWR P5VWDQGDUGPRQWK$

comparison of the Site Boundary and Intermediate Distance data to the Control Location (5H1) data indicate that the ambient gamma radiation levels from the Control Location were consistently higher than all other locations, except 13S2. Location 13S2 historically shows higher ambient gamma radiation, which is due to the rock substrate. The area that this dosimeter is located in has been determined to emanate radon prodigy. NRC Regulatory Guide 4.13, Revision 2 was released in 2019 and provided a new methodology for determining facility-related dose. Exelon procedures were revised to adopt the new methodology and results will be reported per this 20

revision.

D. 10 CFR 20.2002 Permit Storage Area The results of the surface water aquatic monitoring program from Location 24S1 were used to determine if radioactivity from the permit storage area had made it to the Schuylkill River. The data obtained from the gamma analysis program did not detect any migration of radioactivity from the permit storage area.

E. Independent Spent Fuel Storage Installation The results of the ambient gamma radiation level at dosimeter locations 36S2 and 3S1 were used to determine the direct radiation exposure to the nearest residence from the ISFSI pad. The data did not identify any facility-related dose as a result of operation of the ISFSI pad.

F. Land Use Survey A Land Use Survey conducted in the fall of 2020 around Limerick Generating Station (LGS) was performed by Exelon Industrial Services to comply with Bases 3.3.2 of the Limericks Offsite Dose Calculation Manual. The purpose of the land use survey is to look for all potential pathways of radiation to a person. This is accomplished by documenting the nearest resident, milk-producing animal and garden of greater than 500 ft2 in each of the sixteen 22 1/2 degree sectors out to five miles around the site. The distance and direction of all locations from the LGS reactor buildings were positioned using Global Positioning System (GPS) technology.

The 2020 Land Use Survey identified differences in locations for gardens and meat animals between 2019 and 2020. Sixteen (16) new gardens were located this year in sectors NE, E, ESE, SE, S, SSW, SW, WSW, W, and NNW meteorological sectors. Gardens planted in sectors ESE and SE that are maintained for the REMP program were not included in the survey because of location on LGS property. These REMP program gardens are used as the sample locations for the REMP program. There were eight (8) new meat sites identified this year in N, NNW, ESE, SSW, WSW and W sectors. All other locations were the same as in the 2019 report. There were no changes required to the LGS REMP as a result of this survey. There was no observed water usage for agricultural irrigation of root vegetables drawn directly from the Schuylkill River downriver from Limerick Generation Station.

The results of this survey are summarized below:

21

Distance in feet from the LGS Reactor Buildings (Out to 26,400 feet)

Residence Garden Milk Farm Meat Animal Sector Feet Feet Feet Feet 1 N 3,109 3,333 24,775 10,077 2 NNE 2,706 12,399 - 13,418 3 NE 3,469 13,452 - 16,044 4 ENE 3,231 8,241 - 7,451 5 E 2,864 4,117 - -

6 ESE 3,434 3,434 - 12,264 7 SE 3,928 6,376 - 10,903 8 SSE 5,403 6,912 - 8,177 9 S 4,347 6,103 22,114 12,210 10 SSW 5,063 5,732 10,390 10,390 11 SW 3,251 6,319 - 23,145 12 WSW 3,799 4,507 14,177 4,084 13 W 3,627 8,886 - 14,123 14 WNW 3,685 12.022 - -

15 NW 3,619 8,200 - -

16 NNW 5,050 6,473 - 12,065 G. Summary of Results - Inter-laboratory Comparison Program The primary and secondary laboratories analyzed Performance Evaluation (PE) samples of air particulate, air iodine, milk, soil, vegetation, and water matrices for various analytes (Appendix E). The PE samples, supplied by Analytics Inc., Environmental Resource Associates (ERA) and Department of Energy (DOE) Mixed Analyte Performance Evaluation Program (MAPEP),

were evaluated against the following pre-set acceptance criteria:

Analytics Evaluation Criteria Analytics evaluation report provides a ratio of TBEs result and Analytics known value. Since flag values are not assigned by Analytics, TBE evaluates the reported ratios based on internal QC requirements based on the DOE MAPEP criteria.

ERA Evaluation Criteria ERAs evaluation report provides an acceptance range for control and warning limits with associated flag values. ERAs acceptance limits are established per the USEPA, National Environmental Laboratory Accreditation Conference (NELAC), state-specific Performance Testing (PT) program requirements or ERAs SOP for the Generation of Performance Acceptance Limits, as applicable. The acceptance limits are either determined by a regression equation specific to each analyte or a fixed percentage limit promulgated under the appropriate regulatory document.

22

DOE Evaluation Criteria MAPEPs evaluation report provides an acceptance range with associated flag values. MAPEP defines three levels of performance:

x Acceptable (flag = A) - result within +/- 20% of the reference value x Acceptable with Warning (flag = W) - result falls in the +/- 20% to +/-

30% of the reference value x Not Acceptable (flag = N) - bias is greater than 30% of the reference value Note: The Department of Energy (DOE) Mixed Analyte Performance Evaluation Program (MAPEP) samples are created to mimic conditions found at DOE sites which do not resemble typical environmental samples obtained at commercial nuclear power facilities.

1. TBE Laboratory Results For the TBE laboratory, 126 out of 133 analyses performed met the specified acceptance criteria. Seven analyses did not meet the specified acceptance criteria for the following reasons and were addressed through the TBE Corrective Action Program. A summary is found below:

a) The MAPEP February 2020 AP U-DQG8-238 results were evaluated as Not Acceptable. The reported value for U-ZDV

%TVDPSOHDQGWKHNQRZQUHVXOWZDV

%TVDPSOH DFFHSWDQFHUDQJH- 0.098). The reported value for U-ZDV%TVDPSOHDQGWKHNQRZQUHVXOWZDV

%TVDPSOH DFFHSWDQFHUDQJH- 0.101). This sample was run as the workgroup duplicate and had RPDs of 10.4% (U-234) and 11.7% (U-238). After the known results were obtained, the sample was relogged. The filter was completely digested with tracer added originally; the R1 results were almost identical. It was concluded that the recorded tracer amount was actually double, causing the results to be skewed. Lab worksheets have been modified to verify actual tracer amount vs. LIMS data. TBE changed vendors for this cross-check to ERA MRAD during the 2nd half of 2020. Results were acceptable at 97.8% for U-234 and 106% for U-238. (NCR 20-13) b) The ERA Analytics September 2020 milk Sr-89 result was evaluated as Not Acceptable7KHUHSRUWHGYDOXHZDVS&L/DQGWKH

known result was 95.4 (66%). All QC data was reviewed and there were no anomalies. This was the first failure for milk Sr-89 since

DQGWKHUHKDYHRQO\EHHQXSSHUORZHUERXQGDU\ZDUQLQJV

since that time. It is believed that there may have been some Sr-89 loss during sample prep. The December 2020 result was at 92% of 23

the known. (NCR 20-19) c) The ERA October 2020 water I-131 result was evaluated as Not Acceptable7KHUHSRUWHGYDOXHZDVS&L/DQGWKHNQRZQUHVXOW

was 28.2 (acceptance range 23.5 - 33.1). The reported result was 81% of the known, which passes TBE QC criteria. This was the first failure for water I-131. (NCR 20-17) d) The ERA October 2020 water Gross Alpha and Gross Beta results were evaluated as Not Acceptable7KHUHSRUWHGDFFHSWDEOHYDOXHV

and ranges are as follows:

Reported Known Range Gross Alpha 40.0 26.2 13.3 - 34.7 Gross Beta 47.5 69.1 48.0 - 76.0 All QC data was reviewed with no anomalies and a cause for failure could not be determined. This was the first failure for water Gross Beta. A Quick Response follow-up cross-check was analyzed as soon as possible with acceptable results at 96.8% for Gross Alpha and 102% for Gross Beta. (NCR 20-1-13) e) The MAPEP August 2020 soil Ni-63 result was evaluated as Not Acceptable7KHUHSRUWHGYDOXHZDV%TNJDQGWKH

NQRZQUHVXOWZDV%TNJ(acceptance range 686 - 1274). It is believed that some Ni-63 loss occurred during the sample prep step.

(NCR 20-20)

2. EIS Laboratory Results For secondary QC samples, EIS laboratory analyzed gross beta, gamma and low-level I-131. For the EIS Laboratory, 158 out of 162 analyses performed met the specified NRC Resolution Test Criteria (NRC Inspection Manual, Inspection Procedure 84750, March 15, 1994). The EIS Laboratorys results are reported with 2-sigma uncertainty. When evaluating with the NRC Resolution Test, a 1-sigma uncertainty is used to determine Pass or Fail. Failures have been entered into the Corrective Action Program for tracking and to prevent future occurrence. Failures are summarized below:

a. The ERA April 2020 reported Gross Beta UHVXOWZDVS&L/DQGWKH

NQRZQZDVS&L/ DFFHSWDQFHUDQJHZDV- S&L/

Although the reported result passed the low end of the vendor acceptance criteria, but failed NRC Resolution Test Criteria. It was determined that glassware used in preparation is cleaned with nitric acid except for the volumetric pipets, which are rinsed with DI water only. The glass is potentially not as clean and could retain microdroplets of activity on the glass. Going forward, volumetric pipets are rinsed with nitric acid to remove mineral deposit and activity that might be retained on the glass during use and preventing a clean 24

delivery of the sample.

b. The Analytics (EZA) December 2020 result for AP filter and milk Zn-65 were evaluated as failing. The reported result and known are :

Reported Known AP (Detector 2) 105 pCi 149 pCi AP (Detector 5) 111 pCi 149 pCi Milk S&L/ S&L/

The failure was due to an error in mapping the raw data cell to the calculated data cell in the evaluation spreadsheet. The spreadsheet was peer-reviewed and verified. The cell was mapped to the Co-60 raw data instead of the Zn-65 raw data. Had the cell been mapped correctly, the result and uncertainty would have passed NRC acceptance criteria with less than 10% difference from the True value.

3. GEL Laboratory Results For the secondary QC samples, GEL laboratory analyzed only H-3 (water)

IRU/*65(03DQGIRUWKH5*33JDPPDJURVVDOSKDEHWD+-3, and Sr- ZDWHUIRUHDFK )RUWKHVHDnalyses, 94 of 101 cross-check samples met the specified acceptance criteria. Failures were addressed through GELs Corrective Action Program and the pertinent failures are described below:

a) CARR 190225-1192 - ERA 1st quarter 2020 (RAD-120) water:

i. The H-UHSRUWHGYDOXHRIS&L/ZHUHHYDOXDWHGDVNot Acceptable7KHNQRZQUHVXOWZDVS&L/ZLWKDQ acceptance range of 15,600 - S&L/$OOGDWDDQGODE processes were evaluated and no errors were found. It was concluded that the low bias was an isolated occurrence and that the overall process is within control.

ii. Two Sr-89 results were evaluated as Not Acceptable. The UHSRUWHGYDOXHVZHUHS&L/DQGS&L/7KHNQRZQ UHVXOWZDVS&L/ZLWKDQDFFHSWDQFHUange of 47.6 - 67.1 S&L/$UHYLHZRIWKHGDWDDVZHOODVRIWKHSUHSDUDWLRQ processes did not reveal any errors or possible contributors to the high bias. In addition, the reported values are 117% and 114% of the reference value, which is within the labs standard acceptance FULWHULDRI- 25% for Laboratory Control Samples.

iii. The I-UHSRUWHGYDOXHRIS&L/ZDVHYDOXDWHGDV Not Acceptable7KHNQRZQUHVXOWZDVS&L/ZLWKDQDFFHSWDQFH range of 24.9 - S&L/7KHODERUDWory reviewed the data and found no errors. All batch QA samples including a duplicate, met acceptability criteria. The lab will continue to investigate all steps of the analytical process.

25

No permanent corrective DFWLRQVSUHYHQWDWLYHDFWLRQVRU

improvements were needed at this time. The lab must assume unidentified random errors caused the biases because all quality control criteria were met in the batch. Subsequent analyses of these isotopes for drinking water were acceptable in other PT samples during the year.

b) Two ERA 2nd quarter 2020 water Sr-89 results were evaluated as Not Acceptable7KHUHSRUWHGYDOXHVZHUHDQGS&L/DQGWKH

NQRZQUHVXOWZDVS&L/ DFFHSWDQFHUDQJHRI- S&L/

No Corrective Action information was included in the 2020 QA Report.

c) CARR 200902-1287 - The ERA 3rd quarter 2020 water Co-60 result was evaluated as Not Acceptable7KHUHSRUWHGYDOXHZDVS&L/

DQGWKHNQRZQUHVXOWZDVS&L/ DFFHSWDQFHUDQJHRI 77.5 - 97.0 S&L/ 7KHGDWDZDVUHYLHZHGDQGQRDQRPDOLHVZHUHQRWHG7KH

batch duplicate result from the original analysis met the acceptance criteria of the study and replication criteria of the lab with RPDs of

<10%. Laboratory processes were evaluated and no gross errors were found. The other reported analytes for this method were within the limits of the study (except for Ba-133). A definitive contributor to the slightly high bias could not be identified, concluding that this was an isolated occurrence.

1RSHUPDQHQWFRUUHFWLYHDFWLRQVSUHYHQWDWLYHDFWLRQVRU

improvements were needed at this time. The lab will continue to monitor the recoveries to ensure that there are no continued process issues.

The Inter-Laboratory Comparison Program provides evidence of in control counting systems and methods, and that the laboratories are producing accurate and reliable data. Interlaboratory Comparison results may be found in Appendix E.

VI. References A. Environmental Report Operating License Stage, Limerick Generating Station, Units 1 and 2, Volumes 1-5 Philadelphia Electric Company B. NUREG-1302 Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Boiling Water Reactors C. Branch Technical Position Paper, Regulatory Guide 4.8, Revision 1, November 1979 D. 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 26

APPENDIX A RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT

SUMMARY

Intentionally left blank TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LIMERICK GENERATING STATION, 2020 NAME OF FACILITY: LIMERICK GENERATING STATION DOCKET NUMBER: 50-352 & 50-353 LOCATION OF FACILITY: MONTGOMERY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

LOCATIONS LOCATION MEDIUM OR REQUIRED NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSIS ANALYSIS OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS SURFACE WATER H-3 8 200 <LLD <LLD - 0 (PCI/LITER)

GAMMA 24 MN-54 15 <LLD <LLD - 0 CO-58 15 <LLD <LLD - 0 FE-59 30 <LLD <LLD - 0 CO-60 15 <LLD <LLD - 0 ZN-65 30 <LLD <LLD - 0 NB-95 15 <LLD <LLD - 0 A-1 ZR-95 30 <LLD <LLD - 0 I-131 15 <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 I-131 (LOW LVL) 12 1 <LLD <LLD 0 DRINKING WATER GR-B 48 4 3.6 3.9 3.9 15F4 INDICATOR 0 (PCI/LITER) (27/36) (11/12) (9/12) AQUA AMERICA 2.3 - 5.3 2.2 - 7.2 2.3 - 5.3 H-3 16 200 <LLD <LLD - 0 I-131 (LOW LVL) 48 1 <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values. (F) Fraction of dectectable measurements at specified locations are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LIMERICK GENERATING STATION, 2020 NAME OF FACILITY: LIMERICK GENERATING STATION DOCKET NUMBER: 50-352 & 50-353 LOCATION OF FACILITY: MONTGOMERY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

LOCATIONS LOCATION MEDIUM OR REQUIRED NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSIS ANALYSIS OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS DRINKING WATER GAMMA 48 (PCI/LITER) MN-54 15 <LLD <LLD - 0 CO-58 15 <LLD <LLD - 0 FE-59 30 <LLD <LLD - 0 CO-60 15 <LLD <LLD - 0 ZN-65 30 <LLD <LLD - 0 NB-95 15 <LLD <LLD - 0 ZR-95 30 <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 A-2 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 FISH - BOTTOM FEEDER GAMMA 4 (PCI/KG WET) K-40 NA 3438 3362.5 3438 16C5 INDICATOR 0 (2/2) (2/2) (2/2) VINCENT POOL 3389 - 3487 2746 - 3979 3389 - 3487 DOWNSTREAM OF DISCHARGE MN-54 130 <LLD <LLD - 0 CO-58 130 <LLD <LLD - 0 FE-59 260 <LLD <LLD - 0 CO-60 130 <LLD <LLD - 0 ZN-65 260 <LLD <LLD - 0 I-131 NA <LLD <LLD - 0 CS-134 130 <LLD <LLD - 0 CS-137 150 <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values. (F) Fraction of dectectable measurements at specified locations are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LIMERICK GENERATING STATION, 2020 NAME OF FACILITY: LIMERICK GENERATING STATION DOCKET NUMBER: 50-352 & 50-353 LOCATION OF FACILITY: MONTGOMERY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

LOCATIONS LOCATION MEDIUM OR REQUIRED NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSIS ANALYSIS OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS FISH - PREDATOR GAMMA 4 (PCI/KG WET) K-40 NA 2160 2550 2550 29C1 CONTROL 0 (2/2) (2/2) (2/2) POTTSTOWN VICINITY 1938 - 2382 2235 - 2865 2235 - 2865 UPSTREAM OF INTAKE MN-54 130 <LLD <LLD - 0 CO-58 130 <LLD <LLD - 0 FE-59 260 <LLD <LLD - 0 CO-60 130 <LLD <LLD - 0 ZN-65 260 <LLD <LLD - 0 A-3 I-131 NA <LLD <LLD - 0 CS-134 130 <LLD <LLD - 0 CS-137 150 <LLD <LLD - 0 SEDIMENT GAMMA 6 (PCI/KG DRY) BE-7 NA 1082 <LLD 1082 16B2 INDICATOR 0 (1/4) (1/4) LINFIELD BRIDGE 1.35 MILES SSE OF SITE K-40 NA 12188 13140 13140 33A2 CONTROL 0 (4/4) (2/2) (2/2) UPSTREAM OF INTAKE 10650 - 12920 11760 - 14520 11760 - 14520 2.18 MILES SSE OF SITE MN-54 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 I-131 NA <LLD <LLD - 0 CS-134 150 <LLD <LLD - 0 CS-137 180 <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values. (F) Fraction of dectectable measurements at specified locations are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LIMERICK GENERATING STATION, 2020 NAME OF FACILITY: LIMERICK GENERATING STATION DOCKET NUMBER: 50-352 & 50-353 LOCATION OF FACILITY: MONTGOMERY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

LOCATIONS LOCATION MEDIUM OR REQUIRED NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSIS ANALYSIS OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS AIR PARTICULATE GR-B 361 10 13 13 14 13S4 INDICATOR 0 (E-03 PCI/CU.METER) (305/309) (51/52) (49/50) LONGVIEW ROAD 4 - 30 6 - 29 5 - 29 1186 FEET SE OF SITE GAMMA 28 BE-7 NA 68.1 64.3 74.5 13S4 INDICATOR 0 (24/24) (4/4) (4/4) LONGVIEW ROAD 48 - 93 58 - 70 53 - 92 1186 FEET SE OF SITE MN-54 NA <LLD <LLD - 0 A-4 CO-58 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 CS-134 50 <LLD <LLD - 0 CS-137 60 <LLD <LLD - 0 AIR IODINE GAMMA 361 (E-03 PCI/CU.METER) I-131 (GELI) 70 <LLD <LLD - 0 MILK I-131 (LOW LVL) 84 1 <LLD <LLD - 0 (PCI/LITER)

GAMMA 84 K-40 NA 1223 1261 1275 25C1 INDICATOR 0 (63/63) (21/21) (21/21) 890 - 1664 919 - 1463 890 - 1664 2.69 MILES WSW OF SITE CS-134 15 <LLD <LLD - 0 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values. (F) Fraction of dectectable measurements at specified locations are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LIMERICK GENERATING STATION, 2020 NAME OF FACILITY: LIMERICK GENERATING STATION DOCKET NUMBER: 50-352 & 50-353 LOCATION OF FACILITY: MONTGOMERY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

LOCATIONS LOCATION MEDIUM OR REQUIRED NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSIS ANALYSIS OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS VEGETATION GAMMA 32 (PCI/KG WET) BE-7 NA 626.8 1416.2 1416.2 31G1 CONTROL 0 (9/21) (7/11) (7/11) PROUTS'S JOLLYVIEW FARM (CONTROL) 339 - 908 614 - 2570 614 - 2570 71,808 FEET NW K-40 NA 4938 4444.7 5089.5 11S3 INDICATOR 0 (21/21) (11/11) (11/11) LGS INFORMATION CENTER 2722 - 8133 2681 - 6358 3197 - 8133 0.35 MILES ESE OF SITE MN-54 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 A-5 CO-60 NA <LLD <LLD - 0 I-131 60 <LLD <LLD - 0 CS-134 60 <LLD <LLD - 0 CS-137 80 <LLD <LLD - 0 RA-226 NA 1178.5 <LLD 1178.5 13S3 INDICATOR 0 (2/21) (2/10) VINCENT DAM 1084 - 1273 1084 - 1273 0.24 MILES SE OF SITE TH-228 NA 82.3 290.8 290.8 31G1 CONTROL 0 (11/21) (7/11) (7/11) PROUTS'S JOLLYVIEW FARM (CONTROL) 37 - 122 103 - 626 103 - 626 71,808 FEET NW TH-232 NA <LLD <LLD - 0 0

DIRECT RADIATION OSLD-QUARTERLY 320 NA 17.7 22.2 24.6 13S2 INDICATOR 0 (MILLI-ROENTGEN/STD.MO.) (312/312) (8/8) (8/8) 500 KV SUBSTATION 12.5 - 27.4 21.5 - 23.3 23.4 - 25.4 0.41 MILES SE (M) The Mean Values are calculated using the positive values. (F) Fraction of dectectable measurements at specified locations are indicated in parentheses.

Intentionally left blank APPENDIX B LOCATION DESIGNATION, DISTANCE &

DIRECTION, AND SAMPLE COLLECTION &

ANALYTICAL METHODS

Intentionally left blank TABLE B-1: Location Designation and Identification System for the Limerick Generating Station XXYZ - General code for identification of locations, where:

XX - Angular Sector of Sampling Location. The compass is divided into 36 sectors of 10 degrees each with center at Limerick's Units 1 and 2 off-gas vents. Sector 36 is centered due North, and others are numbered in a clockwise direction.

Y - Radial Zone of Sampling Location (in this report, the radial distance from the Limerick vent for all regional stations).

S : on-site location E : 21,120-26,400 feet off-site A : 0-5,280 feet off-site F : 26,400-52,800 feet off-site B : 5,280-10,560 feet off-site G : 52,800-105,600 feet off-site C : 10,560-15,840 feet off-site H : 105,600-528,000 feet off-site D : 15,840-21,120 feet off-site Z - Station's Numerical Designation within sector and zone, using 1, 2, 3... in each sector and zone.

B-1

TABLE B-2: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction Limerick Generating Station, 2020 Location Location Description Distance & Direction From Site A. Surface Water 13B1 Vincent Dam 9,225 feet SE 24S1 Limerick Intake (control) 1,058 feet SW B. Drinking (Potable) Water 15F4 AQUA Water Company 45,514 feet SE 15F7 Phoenixville Water Works 33,400 feet SSE 16C2 PA American 14,034 feet SSE 28F3 Pottstown Borough Authority, Water Distribution Division (control) 30,811 feet WNW C. Milk - bi-weekly / monthly 18E1 22,229 feet S 19B1 10,317 feet SSW 23F1 Control 26,505 feet SW 25C1 14,224 feet WSW D. Air Particulates / Air Iodine 10S3 Keen Road 2,648 feet E 11S1 LGS Information Center 2,017 feet ESE 11S2 LGS Information Center (quality control) 2,017 feet ESE 13S4 Longview Road, near 500 KV Yard 1,186 feet SE 14S1 Longview Road 3,319 feet SSE 15D1 Spring City Substation 16,877 feet SE 22G1 Manor Substation (control) 93,619 feet SW 6C1 Limerick Airport 11,305 feet NE E. Fish 16C5 Vincent Pool Downstream of Discharge 29C1 Pottstown Vicinity (control) Upstream of Intake F. Sediment 16B2 Linfield Bridge 7,128 feet SSE 16C4 Vincent Dam 11,510 feet SSE 33A2 Upstream of Intake (control) 4,435 feet NNW G. Broad Leaf Vegetation 11S3 LGS Information Center 1,848 feet ESE 13S3 LGS 500 KV Yard 1,267 feet SE 31G1 Prout's Jollyview Farm (control) 71,808 feet NW B-2

TABLE B-2: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction Limerick Generating Station, 2020 Location Location Description Distance & Direction From Site I. Environmental Dosimetry - DLR Site Boundary 36S2 Evergreen & Sanatoga Road 183 feet N 3S1 Sanatoga Road 301 feet NNE 5S1 Possum Hollow Road 350 feet NE 7S1 LGS Training Center 099 feet ENE 10S3 Keen Road 648 feet E 11S1 LGS Information Center 017 feet ESE 13S2 500 KV Substation 149 feet SE 14S1 Longview Road 319 feet SSE 18S2 Rail Line along Longview Road 390 feet S 21S2 Near Intake Building 7 feet SSW 23S2 Transmission Tower 793 feet SW 25S2 Sector Site Boundary 445 feet WSW 26S3 Met. Tower #2 088 feet W 29S1 Sector Site Boundary 886 feet WNW 31S1 Sector Site Boundary 395 feet NW 34S2 Met. Tower #1 071 feet NNW Intermediate Distance 36D1 Siren Tower No. 147 18,527 feet N 2E1 Laughing Waters GSC 25,112 feet NNE 4E1 Neiffer Road 25,221 feet NE 7E1 Pheasant Road 22,489 feet ENE 10E1 Royersford Road 20,826 feet E 10F3 Trappe Substation 29,442 feet ESE 13E1 Vaughn Substation 22,772 feet SE 16F1 Pikeland Substation 26,608 feet SSE 19D1 Snowden Substation 18,439 feet S 20F1 Sheeder Substation 27,648 feet SSW 24D1 Porters Mill Substation 20,972 feet SW 25D1 Hoffecker & Keim Streets 21,044 feet WSW 28D2 W. Cedarville Road 20,231 feet W 29E1 Prince Street 26,110 feet WNW 31D2 Poplar Substation 20,446 feet NW 34E1 Varnell Road 24,243 feet NNW Control and Special Interest 5H1 Birch Substation (control) 130,742 feet NE 6C1 Limerick Airport 11,305 feet NE 9C1 Reed Road 11,377 feet E 13C1 King Road 14,980 feet SE 15D1 Spring City Substation 16,877 feet SE 17B1 Linfield Substation 8,462 feet S 20D1 Ellis Woods Road 16,157 feet SSW 31D1 Lincoln Substation 15,853 feet WNW B-3

TABLE B-3: Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Limerick Generating Station, 2020 Sample Analysis Sampling Method Collection Procedure Number Sample Size Analytical Procedure Number Medium TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Monthly composite from CY-ES-240 EIS Collection of water Various Matrices Drinking Gross Beta a continuous water samples for Radiological Analysis 2 gallon Water EIS, CY-ES-206, Operation of the Tennelec S5E Proportional compositor (Limerick Generating Station)

Counter Monthly composite from CY-ES-240 EIS Collection of water TBE, TBE-2012 Radioiodine in Various Matrices Drinking I-131 a continuous water samples for Radiological Analysis 2 gallon EIS, CY-ES-205 Gamma Counting Using the HPGe Detector Water compositor (Limerick Generating Station) with the Genie PC Counting System Monthly composite from CY-ES-240 EIS Collection of water TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Drinking Gamma a continuous water samples for Radiological Analysis 2 gallon EIS, CY-ES-205 Gamma Counting Using the HPGe Detector Water Spectroscopy compositor (Limerick Generating Station) with the Genie PC Counting System Quarterly composite from CY-ES-240 EIS Collection of water TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Drinking Scintillation Tritium a continuous water samples for Radiological Analysis 500 ml Water compositor (Limerick Generating Station) GEL, EPA906.0 Mod for Tritium analysis by Liquid Scintillation Semi-annual samples RMC-ER6 Collection of fish samples for Gamma collected via 1000 grams Fish radiological analysis TBE-2007 Gamma-Emitting Radioisotope Analysis Spectroscopy electroshocking or (wet)

(Limerick Generating Station) other techniques RMC-ER7 Collection of sediment Gamma Sediment Semi-annual grab samples samples for radiological analysis 500 grams (dry) TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis B-4 Spectroscopy (Limerick Generating Station)

One-week composite of 1 filter TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in CY-ES-237 Sample Collection of Air Iodine Various Matrices Air continuous air sampling (approximately Gross Beta and Air Particulate for Radiological Analysis Particulates through glass fiber filter 280 cubic EIS, CY-ES-206 Operation of the Tennelec S5E Proportional (Limerick Generating Station) paper meters weekly) Counter TBE, TBE-2023 Compositing of Samples 13 filters TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Air Gamma Quarterly composite (approximately Particulates Spectroscopy of each station CY-ES-204 Sample Preparation for Gamma 3600 cubic EIS, CY-ES-205 Gamma Counting Using the HPGe Detector and Beta Counting meters) with the Genie PC Counting System 1 filter TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis One-week composite of CY-ES-237 Sample Collection of Air Iodine Gamma (approximately Air Iodine continuous air sampling and Air Particulate for Radiological Analysis EIS, CY-ES-205 Gamma Counting Using the HPGe Detector Spectroscopy 280 cubic through charcoal filter (Limerick Generating Station) with the Genie PC Counting System meters weekly)

Bi-weekly grab sample CY-ES-238 EIS Sample Collection for TBE, TBE-2012 Radioiodine in Various Matrices Milk I-131 when cows are on pasture; Gamma Counting - Milk 2 gallon EIS, CY-ES-205 Gamma Counting Using the HPGe Detector Monthly all other times (Limerick Generating Station) with the Genie PC Counting System Bi-weekly grab sample CY-ES-238 EIS Sample Collection for TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Gamma Milk when cows are on pasture; Gamma Counting - Milk 2 gallon EIS, CY-ES-205 Gamma Counting Using the HPGe Detector Spectroscopy Monthly all other times (Limerick Generating Station) with the Genie PC Counting System CY-ES-239 EIS Sample Collection for Thermoluminescent Quarterly DLRs comprised DLR OSLD for Radiological Analysis 2 dosimeters Mirion Technologies Dosimetry of two dosimeter elements (Limerick Generating Station)

Figure B-1 Environmental Sampling Locations Within 5,280 Feet of the Limerick Generating Station, 2020 B-5

Figure B-2 Environmental Sampling Locations Between 5,280 and 26,400 Feet from the Limerick Generating Station, 2020 B-6

Figure B-3 Environmental Sampling Locations Greater than 26,400 Feet from the Limerick Generating Station, 2020 B-7

Intentionally left blank APPENDIX C DATA TABLES AND FIGURES PRIMARY LABORATORY

Intentionally left blank Table C-I.1 CONCENTRATIONS OF TRITIUM IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 13B1 24S1 12/30/19 - 03/30/20 < 193 < 195 03/30/20 - 06/29/20 < 184 < 184 06/29/20 - 09/29/20 < 172 < 165 09/29/20 - 12/28/20 < 179 < 184 MEAN - -

Table C-I.2 CONCENTRATIONS OF I-131 IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 24S1 12/30/19 - 02/03/20 < 0.7 02/03/20 - 03/02/20 < 0.5 03/02/20 - 03/30/20 < 0.7 03/30/20 - 04/27/20 < 0.7 04/27/20 - 06/02/20 < 0.8 06/02/20 - 06/29/20 < 0.8 06/29/20 - 07/28/20 < 0.8 07/28/20 - 08/31/20 < 0.8 08/31/20 - 09/29/20 < 0.8 09/29/20 - 11/03/20 < 0.9 11/03/20 - 12/01/20 < 0.7 12/01/20 - 12/28/20 < 0.9 MEAN -

C-1

Table C-I.3 CONCENTRATIONS OF GAMMA EMITTERS IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 13B1 12/30/19 - 02/03/20 < 5 < 6 < 10 < 6 < 12 < 7 < 11 < 11 < 6 < 5 < 27 < 9 02/03/20 - 03/02/20 < 5 < 5 < 13 < 5 < 12 < 6 < 11 < 9 < 7 < 6 < 21 < 5 03/02/20 - 03/30/20 < 7 < 5 < 12 < 6 < 11 < 8 < 13 < 11 < 7 < 7 < 35 < 11 03/30/20 - 04/27/20 < 6 < 7 < 10 < 8 < 13 < 6 < 11 < 11 < 9 < 7 < 31 < 12 04/27/20 - 06/02/20 < 7 < 6 < 11 < 10 < 11 < 6 < 10 < 9 < 7 < 7 < 32 < 6 06/02/20 - 06/29/20 < 5 < 5 < 10 < 6 < 9 < 5 < 7 < 10 < 6 < 5 < 29 < 10 06/29/20 - 07/28/20 < 7 < 6 < 12 < 8 < 12 < 5 < 11 < 12 < 9 < 7 < 29 < 8 07/28/20 - 08/31/20 < 7 < 7 < 15 < 7 < 14 < 7 < 12 < 11 < 8 < 6 < 31 < 8 08/31/20 - 09/29/20 < 6 < 5 < 12 < 7 < 12 < 5 < 12 < 11 < 4 < 6 < 24 < 9 09/29/20 - 11/03/20 < 8 < 7 < 15 < 8 < 11 < 6 < 14 < 14 < 8 < 8 < 36 < 11 11/03/20 - 12/01/20 < 9 < 7 < 18 < 9 < 19 < 7 < 14 < 13 < 8 < 10 < 38 < 8 12/01/20 - 12/28/20 < 5 < 5 < 14 < 7 < 14 < 8 < 10 < 11 < 7 < 7 < 30 < 7 C-2 MEAN - - - - - - - - - - - -

24S1 12/30/19 - 02/03/20 < 7 < 8 < 9 < 7 < 15 < 7 < 14 < 10 < 8 < 6 < 35 < 10 02/03/20 - 03/02/20 < 5 < 6 < 9 < 7 < 12 < 8 < 11 < 9 < 6 < 6 < 25 < 12 03/02/20 - 03/30/20 < 7 < 7 < 13 < 8 < 13 < 7 < 12 < 13 < 7 < 6 < 36 < 10 03/30/20 - 04/27/20 < 6 < 6 < 12 < 7 < 13 < 5 < 11 < 11 < 8 < 5 < 25 < 10 04/27/20 - 06/02/20 < 6 < 6 < 12 < 9 < 15 < 8 < 8 < 11 < 7 < 8 < 29 < 13 06/02/20 - 06/29/20 < 5 < 6 < 10 < 7 < 10 < 5 < 9 < 10 < 5 < 6 < 30 < 10 06/29/20 - 07/28/20 < 6 < 7 < 12 < 7 < 13 < 7 < 12 < 9 < 7 < 6 < 32 < 9 07/28/20 - 08/31/20 < 4 < 5 < 10 < 5 < 12 < 6 < 9 < 10 < 6 < 6 < 30 < 8 08/31/20 - 09/29/20 < 5 < 7 < 11 < 7 < 13 < 6 < 12 < 12 < 6 < 5 < 31 < 10 09/29/20 - 11/03/20 < 5 < 7 < 14 < 5 < 15 < 5 < 18 < 12 < 8 < 8 < 30 < 9 11/03/20 - 12/01/20 < 6 < 6 < 13 < 9 < 16 < 4 < 11 < 10 < 7 < 6 < 23 < 9 12/01/20 - 12/28/20 < 6 < 7 < 16 < 8 < 16 < 8 < 12 < 11 < 7 < 7 < 30 < 9 MEAN - - - - - - - - - - - -

Table C-II.1 CONCENTRATIONS OF GROSS BETA IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 15F4 15F7 16C2 28F3 12/30/19 - 02/03/20 2.3 +/- 1.4 4.2 +/- 1.5 4.3 +/- 1.5 3.3 +/- 1.4 02/03/20 - 03/02/20 2.8 +/- 1.2 2.8 +/- 1.5 2.9 +/- 1.6 3.4 +/- 1.6 03/02/20 - 03/30/20 < 2.0 2.7 +/- 1.5 < 2.1 2.2 +/- 1.5 03/30/20 - 04/27/20 < 2.1 < 2.1 < 2.3 2.6 +/- 1.5 04/27/20 - 06/02/20 3.6 +/- 1.5 3.5 +/- 1.5 2.3 +/- 1.5 2.9 +/- 1.5 06/02/20 - 06/29/20 4.6 +/- 1.8 < 2.3 < 2.5 < 2.4 06/29/20 - 07/28/20 4.6 +/- 1.6 4.7 +/- 1.6 2.8 +/- 1.5 4.4 +/- 1.5 07/28/20 - 08/31/20 < 2.1 2.5 +/- 1.5 < 2.3 2.7 +/- 1.6 08/31/20 - 09/29/20 3.4 +/- 1.6 3.9 +/- 1.6 3.7 +/- 1.7 5.3 +/- 1.8 09/29/20 - 11/03/20 5.3 +/- 1.9 3.9 +/- 1.8 4.8 +/- 2.0 4.4 +/- 1.9 11/03/20 - 12/01/20 3.5 +/- 1.5 2.9 +/- 1.5 2.4 +/- 1.5 7.2 +/- 1.8 12/01/20 - 12/28/20 5.3 +/- 1.5 4.2 +/- 1.5 3.7 +/- 1.5 4.8 +/- 1.5 MEAN +/- 2 STD DEV 3.9 +/- 2.1 3.5 +/- 1.5 3.3 +/- 1.8 3.9 +/- 2.9 Table C-II.2 CONCENTRATIONS OF TRITIUM IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 15F4 15F7 16C2 28F3 12/30/19 - 03/30/20 < 191 < 189 < 191 < 190 03/30/20 - 06/29/20 < 186 < 181 < 185 < 183 06/29/20 - 09/29/20 < 172 < 174 < 173 < 176 09/29/20 - 12/28/20 < 189 < 183 < 184 < 180 MEAN - - - -

Table C-II.3 CONCENTRATIONS OF I-131 IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 15F4 15F7 16C2 28F3 12/30/19 - 02/03/20 < 0.9 < 0.9 < 0.9 < 0.9 02/03/20 - 03/02/20 < 0.5 < 0.6 < 0.7 < 0.6 03/02/20 - 03/30/20 < 0.7 < 0.8 < 0.6 < 0.6 03/30/20 - 04/27/20 < 0.6 < 0.6 < 0.6 < 0.9 04/27/20 - 06/02/20 < 0.8 < 0.7 < 0.8 < 0.8 06/02/20 - 06/29/20 < 0.8 < 0.9 < 0.7 < 0.8 06/29/20 - 07/28/20 < 1.0 < 0.8 < 0.9 < 0.9 07/28/20 - 08/31/20 < 1.0 < 0.9 < 0.7 < 0.8 08/31/20 - 09/29/20 < 0.9 < 0.8 < 0.9 < 0.8 09/29/20 - 11/03/20 < 0.9 < 0.9 < 0.9 < 0.8 11/03/20 - 12/01/20 < 0.6 < 0.8 < 0.8 < 0.8 12/01/20 - 12/28/20 < 0.8 < 0.9 < 0.8 < 0.8 MEAN - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-3

Table C-II.4 CONCENTRATIONS OF GAMMA EMITTERS IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 15F4 12/30/19 - 02/03/20 < 7 < 8 < 13 < 6 < 16 < 6 < 13 < 7 < 8 < 32 < 12 02/03/20 - 03/02/20 < 7 < 5 < 15 < 7 < 13 < 7 < 10 < 7 < 6 < 26 < 10 03/02/20 - 03/30/20 < 6 < 7 < 13 < 6 < 11 < 6 < 11 < 6 < 6 < 40 < 12 03/30/20 - 04/27/20 < 6 < 7 < 13 < 8 < 14 < 7 < 12 < 8 < 6 < 38 < 5 04/27/20 - 06/02/20 < 6 < 6 < 11 < 5 < 13 < 6 < 12 < 8 < 7 < 31 < 12 06/02/20 - 06/29/20 < 5 < 6 < 13 < 5 < 13 < 5 < 12 < 5 < 6 < 30 < 9 06/29/20 - 07/28/20 < 7 < 7 < 15 < 9 < 14 < 7 < 9 < 8 < 7 < 36 < 10 07/28/20 - 08/31/20 < 7 < 7 < 15 < 9 < 16 < 6 < 11 < 9 < 6 < 32 < 10 08/31/20 - 09/29/20 < 9 < 8 < 17 < 9 < 16 < 7 < 8 < 5 < 8 < 36 < 12 09/29/20 - 11/03/20 < 7 < 7 < 13 < 6 < 14 < 6 < 12 < 8 < 6 < 36 < 13 11/03/20 - 12/01/20 < 7 < 6 < 14 < 7 < 14 < 7 < 11 < 7 < 7 < 35 < 15 12/01/20 - 12/28/20 < 7 < 7 < 15 < 8 < 14 < 8 < 12 < 10 < 8 < 33 < 8 C-4 MEAN - - - - - - - - - - -

15F7 12/30/19 - 02/03/20 < 6 < 8 < 13 < 6 < 14 < 9 < 12 < 8 < 7 < 34 < 8 02/03/20 - 03/02/20 < 7 < 6 < 15 < 6 < 13 < 9 < 13 < 7 < 6 < 34 < 11 03/02/20 - 03/30/20 < 6 < 7 < 15 < 8 < 14 < 7 < 11 < 7 < 6 < 30 < 12 03/30/20 - 04/27/20 < 6 < 9 < 18 < 7 < 15 < 7 < 12 < 7 < 10 < 36 < 14 04/27/20 - 06/02/20 < 6 < 5 < 13 < 7 < 12 < 7 < 12 < 6 < 7 < 25 < 10 06/02/20 - 06/29/20 < 5 < 4 < 10 < 4 < 9 < 4 < 9 < 4 < 4 < 25 < 7 06/29/20 - 07/28/20 < 6 < 6 < 14 < 10 < 11 < 7 < 13 < 8 < 8 < 33 < 9 07/28/20 - 08/31/20 < 5 < 6 < 12 < 5 < 12 < 5 < 11 < 6 < 5 < 30 < 12 08/31/20 - 09/29/20 < 5 < 6 < 9 < 6 < 14 < 5 < 10 < 7 < 6 < 26 < 7 09/29/20 - 11/03/20 < 6 < 6 < 13 < 8 < 14 < 7 < 10 < 6 < 8 < 39 < 12 11/03/20 - 12/01/20 < 6 < 7 < 13 < 7 < 14 < 6 < 15 < 7 < 7 < 29 < 13 12/01/20 - 12/28/20 < 4 < 7 < 17 < 8 < 16 < 8 < 16 < 8 < 8 < 32 < 13 MEAN - - - - - - - - - - -

Table C-II.4 CONCENTRATIONS OF GAMMA EMITTERS IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 16C2 12/30/19 - 02/03/20 < 5 < 6 < 11 < 6 < 9 < 8 < 14 < 7 < 5 < 30 < 11 02/03/20 - 03/02/20 < 8 < 7 < 12 < 8 < 13 < 9 < 14 < 10 < 7 < 40 < 9 03/02/20 - 03/30/20 < 6 < 6 < 11 < 6 < 10 < 6 < 11 < 5 < 6 < 30 < 12 03/30/20 - 04/27/20 < 8 < 5 < 13 < 8 < 13 < 5 < 10 < 7 < 7 < 26 < 11 04/27/20 - 06/02/20 < 6 < 7 < 14 < 8 < 14 < 8 < 12 < 8 < 7 < 26 < 8 06/02/20 - 06/29/20 < 5 < 5 < 10 < 5 < 11 < 5 < 10 < 5 < 5 < 24 < 8 06/29/20 - 07/28/20 < 7 < 5 < 13 < 7 < 12 < 6 < 10 < 8 < 7 < 31 < 8 07/28/20 - 08/31/20 < 7 < 8 < 11 < 4 < 19 < 6 < 14 < 7 < 8 < 37 < 11 08/31/20 - 09/29/20 < 6 < 6 < 14 < 6 < 15 < 7 < 13 < 8 < 6 < 32 < 8 09/29/20 - 11/03/20 < 7 < 7 < 15 < 7 < 16 < 7 < 10 < 6 < 7 < 37 < 13 11/03/20 - 12/01/20 < 7 < 7 < 15 < 7 < 17 < 8 < 13 < 7 < 6 < 40 < 11 12/01/20 - 12/28/20 < 5 < 5 < 18 < 8 < 13 < 7 < 12 < 8 < 7 < 36 < 10 C-5 MEAN - - - - - - - - - - -

28F3 12/30/19 - 02/03/20 < 6 < 5 < 13 < 5 < 12 < 7 < 13 < 7 < 5 < 29 < 8 02/03/20 - 03/02/20 < 8 < 7 < 14 < 8 < 14 < 7 < 13 < 9 < 7 < 28 < 12 03/02/20 - 03/30/20 < 5 < 5 < 12 < 5 < 12 < 7 < 9 < 6 < 6 < 27 < 9 03/30/20 - 04/27/20 < 7 < 7 < 12 < 6 < 13 < 7 < 11 < 7 < 7 < 30 < 10 04/27/20 - 06/02/20 < 6 < 5 < 13 < 8 < 14 < 7 < 13 < 7 < 6 < 30 < 11 06/02/20 - 06/29/20 < 4 < 4 < 12 < 5 < 10 < 6 < 9 < 5 < 5 < 26 < 7 06/29/20 - 07/28/20 < 5 < 8 < 18 < 6 < 13 < 7 < 12 < 6 < 8 < 18 < 14 07/28/20 - 08/31/20 < 7 < 6 < 16 < 8 < 12 < 8 < 8 < 10 < 7 < 34 < 10 08/31/20 - 09/29/20 < 7 < 8 < 14 < 7 < 13 < 8 < 12 < 7 < 7 < 31 < 10 09/29/20 - 11/03/20 < 8 < 7 < 15 < 8 < 15 < 8 < 13 < 7 < 7 < 39 < 13 11/03/20 - 12/01/20 < 8 < 9 < 15 < 9 < 15 < 6 < 12 < 9 < 8 < 37 < 7 12/01/20 - 12/28/20 < 6 < 7 < 13 < 5 < 15 < 6 < 10 < 8 < 6 < 28 < 8 MEAN - - - - - - - - - - -

Table C-III.1 CONCENTRATIONS OF GAMMA EMITTERS IN PREDATOR AND BOTTOM FEEDER (FISH)

SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION SITE PERIOD K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 I-131 Cs-134 Cs-137 16C5 PREDATOR 05/27/20 1938 +/- 963 < 60 < 45 < 92 < 59 < 124 < 75 < 46 < 65 11/19/20 2382 +/- 877 < 73 < 39 < 76 < 37 < 118 < 69 < 56 < 60 MEAN +/- 2 STD DEV 2160 +/- 628 - - - - - - - -

16C5 BOTTOM FEEDER 05/27/20 3487 +/- 939 < 75 < 62 < 132 < 49 < 161 < 104 < 86 < 67 11/19/20 3389 +/- 682 < 33 < 37 < 77 < 37 < 79 < 46 < 37 < 36 MEAN +/- 2 STD DEV 3438 +/- 139 - - - - - - - -

C-6 29C1 PREDATOR 05/28/20 2865 +/- 828 < 47 < 39 < 90 < 55 < 89 < 63 < 56 < 53 11/18/20 2235 +/- 721 < 40 < 38 < 51 < 29 < 92 < 51 < 44 < 43 MEAN +/- 2 STD DEV 2550 +/- 891 - - - - - - - -

29C1 BOTTOM FEEDER 05/28/20 3979 +/- 1287 < 87 < 98 < 196 < 112 < 149 < 118 < 85 < 92 10/23/20 2746 +/- 898 < 55 < 41 < 100 < 46 < 102 < 67 < 56 < 49 MEAN +/- 2 STD DEV 3363 +/- 1744 - - - - - - - -

THE MEAN AND 2-STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES

Table C-IV.1 CONCENTRATIONS OF GAMMA EMITTERS IN SEDIMENT SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/KG DRY +/- 2 SIGMA COLLECTION SITE PERIOD Be-7 K-40 Mn-54 Co-58 Co-60 I-131 Cs-134 Cs-137 16B2 06/10/20 1082 +/- 679 12920 +/- 1878 < 105 < 71 < 78 < 168 < 104 < 112 11/20/20 < 1047 12650 +/- 1919 < 95 < 107 < 98 < 203 < 130 < 115 MEAN +/- 2 STD DEV 1082 +/- 0 12785 +/- 382 - - - - - -

16C4 06/10/20 < 1127 10650 +/- 1592 < 103 < 99 < 100 < 184 < 138 < 118 11/20/20 < 902 12530 +/- 1849 < 92 < 89 < 87 < 193 < 112 < 89 MEAN +/- 2 STD DEV - 11590 +/- 2659 - - - - - -

33A2 06/10/20 < 848 11760 +/- 1885 < 71 < 79 < 100 < 134 < 128 < 96 C-7 11/20/20 < 972 14520 +/- 2004 < 82 < 88 < 103 < 190 < 116 < 114 MEAN +/- 2 STD DEV - 13140 +/- 3903 - - - - - -

THE MEAN AND 2-STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES

Table C-V.1 CONCENTRATIONS OF GROSS BETA IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF E-03 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III PERIOD 10S3 11S1 13S4 14S1 6C1 15D1 22G1 12/30/19 - 01/06/20 9 +/- 3 11 +/- 4 6 +/- 3 10 +/- 4 11 +/- 4 10 +/- 4 10 +/- 4 01/06/20 - 01/13/20 12 +/- 3 14 +/- 3 11 +/- 3 11 +/- 3 10 +/- 3 13 +/- 3 14 +/- 3 01/13/20 - 01/21/20 13 +/- 3 16 +/- 4 13 +/- 3 16 +/- 3 15 +/- 3 14 +/- 3 18 +/- 4 01/21/20 - 01/27/20 < 6 6 +/- 4 < 6 11 +/- 4 8 +/- 4 9 +/- 4 8 +/- 4 01/27/20 - 02/03/20 8 +/- 3 9 +/- 3 8 +/- 3 6 +/- 3 11 +/- 3 9 +/- 3 6 +/- 3 02/03/20 - 02/10/20 7 +/- 3 9 +/- 3 8 +/- 3 9 +/- 3 11 +/- 3 7 +/- 3 10 +/- 3 02/10/20 - 02/17/20 9 +/- 4 8 +/- 3 9 +/- 4 8 +/- 3 13 +/- 4 8 +/- 3 10 +/- 4 02/17/20 - 02/24/20 21 +/- 4 18 +/- 4 20 +/- 4 19 +/- 4 20 +/- 4 15 +/- 4 17 +/- 4 02/24/20 - 03/02/20 11 +/- 4 12 +/- 4 10 +/- 4 11 +/- 4 12 +/- 4 13 +/- 4 10 +/- 4 03/02/20 - 03/09/20 12 +/- 4 9 +/- 3 10 +/- 4 12 +/- 4 9 +/- 3 13 +/- 4 11 +/- 3 03/09/20 - 03/16/20 12 +/- 4 12 +/- 4 13 +/- 4 14 +/- 4 11 +/- 4 14 +/- 4 13 +/- 4 03/16/20 - 03/23/20 16 +/- 4 10 +/- 4 15 +/- 4 13 +/- 4 17 +/- 4 15 +/- 4 9 +/- 4 03/23/20 - 03/30/20 6 +/- 3 4 +/- 3 5 +/- 3 6 +/- 3 6 +/- 3 7 +/- 3 < 4 03/30/20 - 04/06/20 9 +/- 3 8 +/- 3 9 +/- 3 9 +/- 3 5 +/- 3 9 +/- 3 8 +/- 3 04/06/20 - 04/13/20 13 +/- 4 14 +/- 4 18 +/- 4 14 +/- 4 12 +/- 4 14 +/- 4 15 +/- 4 04/13/20 - 04/20/20 15 +/- 4 10 +/- 4 12 +/- 4 14 +/- 4 11 +/- 4 12 +/- 4 11 +/- 4 04/20/20 - 04/27/20 11 +/- 4 7 +/- 3 8 +/- 3 8 +/- 4 11 +/- 4 14 +/- 4 10 +/- 4 04/27/20 - 05/04/20 13 +/- 4 11 +/- 3 12 +/- 4 11 +/- 4 12 +/- 4 13 +/- 4 12 +/- 4 05/04/20 - 05/11/20 7 +/- 3 7 +/- 3 9 +/- 4 12 +/- 4 11 +/- 4 5 +/- 3 10 +/- 3 05/11/20 - 05/18/20 14 +/- 4 13 +/- 4 15 +/- 4 17 +/- 4 15 +/- 4 16 +/- 4 16 +/- 4 05/18/20 - 05/26/20 10 +/- 3 7 +/- 3 10 +/- 3 8 +/- 3 12 +/- 3 8 +/- 3 8 +/- 3 05/26/20 - 06/02/20 10 +/- 3 7 +/- 3 12 +/- 4 8 +/- 3 10 +/- 4 8 +/- 3 8 +/- 3 06/02/20 - 06/08/20 13 +/- 4 11 +/- 4 17 +/- 5 17 +/- 5 14 +/- 5 16 +/- 8 14 +/- 4 06/08/20 - 06/15/20 10 +/- 4 7 +/- 3 12 +/- 4 12 +/- 4 11 +/- 4 13 +/- 4 11 +/- 4 06/15/20 - 06/22/20 9 +/- 3 7 +/- 3 9 +/- 4 7 +/- 3 5 +/- 3 9 +/- 4 7 +/- 3 06/22/20 - 06/29/20 13 +/- 4 12 +/- 4 16 +/- 4 15 +/- 4 15 +/- 4 15 +/- 4 13 +/- 4 06/29/20 - 07/06/20 16 +/- 4 15 +/- 4 19 +/- 4 17 +/- 4 16 +/- 4 18 +/- 4 16 +/- 4 07/06/20 - 07/13/20 9 +/- 4 8 +/- 4 12 +/- 4 11 +/- 4 11 +/- 4 10 +/- 4 10 +/- 3 07/13/20 - 07/20/20 14 +/- 4 12 +/- 3 15 +/- 4 14 +/- 4 14 +/- 4 14 +/- 4 13 +/- 3 07/20/20 - 07/28/20 13 +/- 3 15 +/- 4 19 +/- 10 23 +/- 4 13 +/- 4 14 +/- 4 16 +/- 4 07/28/20 - 08/04/20 15 +/- 4 13 +/- 4 (1) 17 +/- 4 16 +/- 4 15 +/- 4 14 +/- 4 08/04/20 - 08/10/20 15 +/- 4 14 +/- 4 (1) 14 +/- 4 17 +/- 4 14 +/- 4 18 +/- 5 08/10/20 - 08/17/20 21 +/- 4 5 +/- 3 18 +/- 5 27 +/- 5 19 +/- 4 17 +/- 4 23 +/- 5 08/17/20 - 08/24/20 13 +/- 4 < 4 13 +/- 4 12 +/- 4 14 +/- 4 13 +/- 4 13 +/- 4 08/24/20 - 08/31/20 13 +/- 4 < 5 18 +/- 4 18 +/- 4 17 +/- 4 14 +/- 4 12 +/- 4 08/31/20 - 09/08/20 13 +/- 3 14 +/- 3 15 +/- 3 14 +/- 3 20 +/- 4 12 +/- 3 11 +/- 3 09/08/20 - 09/14/20 11 +/- 4 12 +/- 4 10 +/- 4 13 +/- 4 15 +/- 4 12 +/- 4 12 +/- 4 09/14/20 - 09/21/20 15 +/- 4 11 +/- 4 18 +/- 4 16 +/- 4 13 +/- 4 13 +/- 4 10 +/- 4 09/21/20 - 09/29/20 22 +/- 4 18 +/- 4 29 +/- 4 23 +/- 4 25 +/- 4 24 +/- 4 21 +/- 4 09/29/20 - 10/05/20 10 +/- 4 12 +/- 4 14 +/- 4 11 +/- 4 10 +/- 4 10 +/- 4 8 +/- 4 10/05/20 - 10/12/20 23 +/- 4 16 +/- 4 25 +/- 4 18 +/- 4 21 +/- 4 21 +/- 4 14 +/- 4 10/12/20 - 10/19/20 10 +/- 3 8 +/- 3 15 +/- 4 10 +/- 3 10 +/- 3 9 +/- 3 10 +/- 3 10/19/20 - 10/26/20 10 +/- 4 8 +/- 3 11 +/- 4 12 +/- 4 12 +/- 4 10 +/- 4 7 +/- 3 10/26/20 - 11/03/20 9 +/- 3 9 +/- 3 10 +/- 3 8 +/- 3 10 +/- 3 10 +/- 3 9 +/- 3 11/03/20 - 11/10/20 22 +/- 4 23 +/- 4 27 +/- 5 29 +/- 5 23 +/- 4 30 +/- 5 29 +/- 5 11/10/20 - 11/16/20 12 +/- 4 11 +/- 4 18 +/- 5 15 +/- 4 16 +/- 5 16 +/- 5 15 +/- 4 11/16/20 - 11/23/20 10 +/- 3 10 +/- 4 13 +/- 4 11 +/- 4 15 +/- 4 13 +/- 4 12 +/- 4 11/23/20 - 12/01/20 17 +/- 4 16 +/- 4 14 +/- 4 15 +/- 4 16 +/- 4 15 +/- 4 17 +/- 4 12/01/20 - 12/07/20 11 +/- 4 7 +/- 4 10 +/- 4 10 +/- 4 10 +/- 4 11 +/- 4 10 +/- 4 12/07/20 - 12/14/20 27 +/- 5 11 +/- 4 23 +/- 4 25 +/- 4 22 +/- 4 23 +/- 4 24 +/- 4 12/14/20 - 12/21/20 15 +/- 3 (1) 14 +/- 3 12 +/- 3 15 +/- 3 13 +/- 3 9 +/- 3 12/21/20 - 12/28/20 14 +/- 4 13 +/- 4 11 +/- 4 13 +/- 4 14 +/- 4 15 +/- 4 12 +/- 4 MEAN +/- 2 STD DEV 13 +/- 9 11 +/- 7 14 +/- 10 14 +/- 10 13 +/- 8 13 +/- 9 13 +/- 9 THE MEAN AND 2-STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES (1) SEE PROGRAM EXCEPTIONS SECTION FOR EXPLANATION C-8

Table C-V.2 MONTHLY AND YEARLY MEAN VALUES OF GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF E-03 PCI/CU METER +/- 2 SIGMA GROUP I - ON-SITE LOCATIONS GROUP II - INTERMEDIATE DISTANCE LOCATIONS GROUP III - CONTROL LOCATIONS COLLECTION MIN MAX MEAN COLLECTION MIN MAX MEAN COLLECTION MIN MAX MEAN PERIOD +/- 2SD PERIOD +/- 2SD PERIOD +/- 2SD 12/30/19 - 02/03/20 6 16 11 +/- 6 12/30/19 - 02/03/20 8 15 11 +/- 5 12/30/19 - 02/03/20 6 18 11 +/- 9 02/03/20 - 03/02/20 7 21 12 +/- 9 02/03/20 - 03/02/20 7 20 12 +/- 8 02/03/20 - 03/02/20 10 17 12 +/- 7 03/02/20 - 03/30/20 4 16 11 +/- 7 03/02/20 - 03/30/20 6 17 12 +/- 8 03/02/20 - 03/23/20 9 13 11 +/- 4 03/30/20 - 05/04/20 7 18 11 +/- 6 03/30/20 - 05/04/20 5 14 11 +/- 5 03/30/20 - 05/04/20 8 15 11 +/- 5 05/04/20 - 06/02/20 7 17 10 +/- 6 05/04/20 - 06/02/20 5 16 11 +/- 7 05/04/20 - 06/02/20 8 16 10 +/- 8 06/02/20 - 06/29/20 7 17 12 +/- 7 06/02/20 - 06/29/20 5 16 12 +/- 8 06/02/20 - 06/29/20 7 14 11 +/- 7 06/29/20 - 08/04/20 8 23 15 +/- 7 06/29/20 - 08/04/20 10 18 14 +/- 5 06/29/20 - 08/04/20 10 16 14 +/- 5 08/04/20 - 08/31/20 5 27 15 +/- 11 08/04/20 - 08/31/20 13 19 16 +/- 5 08/04/20 - 08/31/20 12 23 17 +/- 10 08/31/20 - 09/29/20 10 29 16 +/- 10 08/31/20 - 09/29/20 12 25 17 +/- 11 08/31/20 - 09/29/20 10 21 13 +/- 10 09/29/20 - 11/03/20 8 25 12 +/- 10 09/29/20 - 11/03/20 9 21 12 +/- 9 09/29/20 - 11/03/20 7 14 10 +/- 6 C-9 11/03/20 - 12/01/20 10 29 16 +/- 12 11/03/20 - 12/01/20 13 30 18 +/- 11 11/03/20 - 12/01/20 12 29 18 +/- 14 12/01/20 - 12/28/20 7 27 14 +/- 12 12/01/20 - 12/28/20 10 23 15 +/- 10 12/01/20 - 12/28/20 9 24 14 +/- 14 12/30/19 - 12/28/20 4 29 13 +/- 9 12/30/19 - 12/28/20 5 30 13 +/- 9 12/30/19 - 12/28/20 6 29 13 +/- 9

Table C-V.3 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF E-03 PCI/CU METER +/- 2 SIGMA COLLECTION SITE PERIOD Be-7 Mn-54 Co-58 Co-60 Cs-134 Cs-137 10S3 12/30/19 - 03/30/20 63 +/- 17 < 2 < 2 < 1 < 2 < 2 03/30/20 - 06/29/20 93 +/- 22 < 3 < 2 < 2 < 3 < 2 06/29/20 - 09/29/20 71 +/- 17 < 1 < 2 < 2 < 2 < 2 09/29/20 - 12/28/20 49 +/- 18 < 1 < 2 < 2 < 2 < 2 MEAN +/- 2 STD DEV 69 +/- 37 - - - - -

11S1 12/30/19 - 03/30/20 48 +/- 21 < 3 < 3 < 2 < 2 < 2 03/30/20 - 06/29/20 62 +/- 21 < 2 < 2 < 2 < 2 < 2 06/29/20 - 09/29/20 59 +/- 20 < 2 < 2 < 2 < 3 < 2 09/29/20 - 12/28/20 59 +/- 19 < 2 < 2 < 3 < 2 < 2 MEAN +/- 2 STD DEV 57 +/- 12 - - - - -

13S4 12/30/19 - 03/30/20 67 +/- 18 < 2 < 2 < 3 < 2 < 2 03/30/20 - 06/29/20 86 +/- 21 < 2 < 2 < 3 < 2 < 2 06/29/20 - 09/29/20 92 +/- 23 < 3 < 3 < 2 < 3 < 3 09/29/20 - 12/28/20 53 +/- 18 < 2 < 2 < 2 < 2 < 2 MEAN +/- 2 STD DEV 74 +/- 35 - - - - -

14S1 12/30/19 - 03/30/20 59 +/- 21 < 4 < 3 < 3 < 4 < 3 03/30/20 - 06/29/20 73 +/- 28 < 3 < 3 < 4 < 4 < 3 06/29/20 - 09/29/20 83 +/- 19 < 2 < 2 < 1 < 2 < 2 09/29/20 - 12/28/20 49 +/- 17 < 1 < 2 < 2 < 2 < 2 MEAN +/- 2 STD DEV 66 +/- 30 - - - - -

15D1 12/30/19 - 03/30/20 64 +/- 17 < 2 < 2 < 2 < 2 < 2 03/30/20 - 06/29/20 83 +/- 28 < 3 < 4 < 4 < 4 < 3 06/29/20 - 09/29/20 75 +/- 15 < 3 < 2 < 1 < 2 < 2 09/29/20 - 12/28/20 67 +/- 19 < 3 < 3 < 3 < 2 < 2 MEAN +/- 2 STD DEV 72 +/- 17 - - - - -

22G1 12/30/19 - 03/30/20 59 +/- 15 < 1 < 2 < 2 < 2 < 2 03/30/20 - 06/29/20 70 +/- 18 < 1 < 2 < 1 < 2 < 1 06/29/20 - 09/29/20 70 +/- 21 < 3 < 4 < 4 < 4 < 3 09/29/20 - 12/28/20 57 +/- 15 < 2 < 2 < 2 < 2 < 2 MEAN +/- 2 STD DEV 64 +/- 14 - - - - -

6C1 12/30/19 - 03/30/20 73 +/- 18 < 1 < 1 < 2 < 1 < 2 03/30/20 - 06/29/20 67 +/- 18 < 2 < 2 < 2 < 1 < 1 06/29/20 - 09/29/20 83 +/- 22 < 1 < 2 < 3 < 2 < 2 09/29/20 - 12/28/20 54 +/- 18 < 3 < 2 < 3 < 3 < 2 MEAN +/- 2 STD DEV 70 +/- 24 - - - - -

THE MEAN AND 2-STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-10

Table C-VI.1 CONCENTRATIONS OF I-131 IN AIR IODINE SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF E-03 PCI/CU METER + 2 SIGMA COLLECTION GROUP I GROUP II GROUP III PERIOD 10S3 11S1 13S4 14S1 6C1 15D1 22G1 12/30/19 - 01/06/20 < 19 < 19 < 35 < 19 < 19 < 16 < 34 01/06/20 - 01/13/20 < 35 < 29 < 28 < 29 < 33 < 29 < 12 01/13/20 - 01/21/20 < 18 < 21 < 25 < 20 < 21 < 21 < 24 01/21/20 - 01/27/20 < 42 < 20 < 24 < 22 < 39 < 22 < 22 01/27/20 - 02/03/20 < 12 < 28 < 17 < 28 < 27 < 28 < 17 02/03/20 - 02/10/20 < 28 < 14 < 28 < 27 < 27 < 27 < 28 02/10/20 - 02/17/20 < 35 < 15 < 21 < 35 < 35 < 35 < 28 02/17/20 - 02/24/20 < 25 < 25 < 29 < 25 < 13 < 25 < 28 02/24/20 - 03/02/20 < 28 < 27 < 14 < 18 < 27 < 27 < 29 03/02/20 - 03/09/20 < 16 < 22 < 19 < 22 < 17 < 22 < 21 03/09/20 - 03/16/20 < 22 < 21 < 38 < 21 < 21 < 18 < 36 03/16/20 - 03/23/20 < 25 < 11 < 20 < 22 < 25 < 22 < 22 03/23/20 - 03/30/20 < 16 < 15 < 28 < 28 < 16 < 28 < 28 03/30/20 - 04/06/20 < 24 < 24 < 10 < 24 < 25 < 24 < 25 04/06/20 - 04/13/20 < 22 < 38 < 38 < 16 < 23 < 39 < 36 04/13/20 - 04/20/20 < 27 < 27 < 22 < 26 < 14 < 27 < 16 04/20/20 - 04/27/20 < 19 < 20 < 23 < 16 < 20 < 19 < 23 04/27/20 - 05/04/20 < 24 < 24 < 25 < 25 < 24 < 21 < 25 05/04/20 - 05/11/20 < 35 < 23 < 24 < 24 < 35 < 23 < 13 05/11/20 - 05/18/20 < 30 < 42 < 18 < 42 < 30 < 42 < 42 05/18/20 - 05/26/20 < 19 < 19 < 14 < 19 < 11 < 19 < 36 05/26/20 - 06/02/20 < 17 < 32 < 31 < 14 < 17 < 31 < 32 06/02/20 - 06/08/20 < 28 < 29 < 44 < 35 < 29 < 32 < 39 06/08/20 - 06/15/20 < 30 < 13 < 23 < 30 < 30 < 30 < 23 06/15/20 - 06/22/20 < 25 < 12 < 21 < 22 < 25 < 21 < 20 06/22/20 - 06/29/20 < 28 < 28 < 12 < 30 < 29 < 28 < 27 06/29/20 - 07/06/20 < 17 < 17 < 9 < 10 < 17 < 17 < 13 07/06/20 - 07/13/20 < 17 < 40 < 26 < 37 < 38 < 38 < 24 07/13/20 - 07/20/20 < 18 < 11 < 30 < 18 < 18 < 18 < 30 07/20/20 - 07/28/20 < 28 < 27 < 17 < 12 < 28 < 28 < 13 07/28/20 - 08/04/20 < 32 < 32 (1) < 26 < 14 < 32 < 32 08/04/20 - 08/10/20 < 33 < 13 (1) < 31 < 33 < 32 < 18 08/10/20 - 08/17/20 < 20 < 40 < 24 < 40 < 13 < 40 < 41 08/17/20 - 08/24/20 < 44 < 22 < 23 < 11 < 44 < 22 < 22 08/24/20 - 08/31/20 < 35 < 37 < 27 < 35 < 15 < 36 < 27 08/31/20 - 09/08/20 < 18 < 51 < 51 < 51 < 17 < 51 < 21 09/08/20 - 09/14/20 < 28 < 32 < 14 < 32 < 12 < 32 < 31 09/14/20 - 09/21/20 < 18 < 39 < 17 < 39 < 17 < 39 < 38 09/21/20 - 09/29/20 < 24 < 11 < 10 < 24 < 24 < 24 < 13 09/29/20 - 10/05/20 < 21 < 48 < 22 < 48 < 21 < 50 < 50 10/05/20 - 10/12/20 < 19 < 19 < 18 < 19 < 16 < 19 < 18 10/12/20 - 10/19/20 < 23 < 23 < 26 < 23 < 15 < 24 < 13 10/19/20 - 10/26/20 < 33 < 33 < 12 < 18 < 33 < 33 < 19 10/26/20 - 11/03/20 < 40 < 40 < 26 < 40 < 17 < 40 < 25 11/03/20 - 11/10/20 < 32 < 27 < 27 < 27 < 32 < 23 < 28 11/10/20 - 11/16/20 < 14 < 26 < 26 < 26 < 27 < 27 < 27 11/16/20 - 11/23/20 < 52 < 66 < 50 < 54 < 23 < 53 < 48 11/23/20 - 12/01/20 < 14 < 25 < 24 < 24 < 26 < 24 < 24 12/01/20 - 12/07/20 < 46 < 47 < 20 < 20 < 45 < 45 < 32 12/07/20 - 12/14/20 < 26 < 35 < 17 < 25 < 11 < 26 < 13 12/14/20 - 12/21/20 < 45 (1) < 39 < 45 < 45 < 47 < 25 12/21/20 - 12/28/20 < 23 < 24 < 23 < 23 < 23 < 23 < 11 MEAN - - - - - - -

(1) SEE PROGRAM EXCEPTIONS SECTION FOR EXPLANATION C-11

Table C-VII.1 CONCENTRATIONS OF I-131 IN MILK SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION CONTROL FARM INDICATOR FARMS PERIOD 23F1 18E1 19B1 25C1 01/14/20 < 0.9 < 0.8 < 0.9 < 0.9 02/10/20 < 0.8 < 0.8 < 0.7 < 0.8 03/10/20 < 0.6 < 0.7 < 0.7 < 0.8 04/06/20 < 0.6 < 0.8 < 0.8 < 0.7 04/21/20 < 0.6 < 0.7 < 0.7 < 0.6 05/05/20 < 0.6 < 0.8 < 0.7 < 0.7 05/19/20 < 0.7 < 0.8 < 0.8 < 0.7 06/01/20 < 0.7 < 0.7 < 0.7 < 0.7 06/16/20 < 0.6 < 0.7 < 0.9 < 0.6 06/29/20 < 0.7 < 0.8 < 0.7 < 0.8 07/14/20 < 0.8 < 0.7 < 0.9 < 0.6 07/27/20 < 0.7 < 0.8 < 0.8 < 0.8 08/10/20 < 0.8 < 0.8 < 0.8 < 0.9 08/24/20 < 0.8 < 0.8 < 0.8 < 0.7 09/08/20 < 0.8 < 0.8 < 0.8 < 0.7 09/21/20 < 0.8 < 0.8 < 0.8 < 0.8 10/06/20 < 0.9 < 0.8 < 0.9 < 0.8 10/19/20 < 0.7 < 0.9 < 0.9 < 0.8 11/03/20 < 0.9 < 0.9 < 0.9 < 0.9 11/17/20 < 0.8 < 0.9 < 0.8 < 0.7 12/07/20 < 0.9 12/11/20 < 0.8 < 0.8 < 0.8 MEAN - - - -

C-12

Table C-VII.2 CONCENTRATIONS OF GAMMA EMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD K-40 Cs-134 Cs-137 Ba-140 La-140 18E1 01/14/20 1241 +/- 107 < 4 < 4 < 16 < 4 02/10/20 1228 +/- 180 < 9 < 8 < 32 < 9 03/10/20 1297 +/- 167 < 7 < 7 < 29 < 8 04/06/20 1243 +/- 199 < 7 < 8 < 31 < 9 04/21/20 1252 +/- 183 < 8 < 9 < 25 < 6 05/05/20 1155 +/- 166 < 8 < 10 < 34 < 11 05/19/20 1069 +/- 197 < 7 < 8 < 20 < 7 06/01/20 1153 +/- 147 < 7 < 7 < 22 < 8 06/16/20 1137 +/- 162 < 8 < 7 < 27 < 9 06/29/20 1134 +/- 180 < 8 < 8 < 27 < 8 07/14/20 1047 +/- 171 < 11 < 7 < 28 < 9 07/27/20 1028 +/- 179 < 7 < 8 < 29 < 10 08/10/20 1239 +/- 178 < 10 < 8 < 32 < 5 08/24/20 1218 +/- 167 < 7 < 7 < 22 < 7 09/08/20 1249 +/- 176 < 9 < 7 < 24 < 10 09/21/20 1122 +/- 186 < 7 < 8 < 30 < 13 10/06/20 992 +/- 163 < 10 < 9 < 35 < 10 10/19/20 1216 +/- 187 < 8 < 9 < 31 < 8 11/03/20 1224 +/- 165 < 9 < 7 < 22 < 8 11/17/20 1026 +/- 169 < 9 < 8 < 28 < 6 12/11/20 1203 +/- 181 < 11 < 8 < 34 < 9 MEAN +/- 2 STD DEV 1165 +/- 178 - - - -

19B1 01/14/20 1314 +/- 179 < 8 < 6 < 24 < 7 02/10/20 1141 +/- 152 < 7 < 6 < 22 < 5 03/10/20 1103 +/- 153 < 8 < 7 < 23 < 9 04/06/20 1220 +/- 111 < 6 < 5 < 18 < 6 04/21/20 1179 +/- 160 < 7 < 7 < 23 < 8 05/05/20 1144 +/- 160 < 8 < 8 < 29 < 10 05/19/20 1149 +/- 150 < 8 < 7 < 25 < 9 06/01/20 1203 +/- 161 < 10 < 8 < 39 < 10 06/16/20 1056 +/- 166 < 8 < 9 < 29 < 9 06/29/20 1426 +/- 163 < 10 < 7 < 23 < 10 07/14/20 1412 +/- 186 < 9 < 8 < 27 < 6 07/27/20 1254 +/- 175 < 10 < 8 < 24 < 8 08/10/20 1265 +/- 193 < 9 < 10 < 31 < 7 08/24/20 1109 +/- 198 < 10 < 9 < 21 < 12 09/08/20 1337 +/- 155 < 8 < 7 < 31 < 8 09/21/20 1268 +/- 200 < 8 < 6 < 32 < 8 10/06/20 1181 +/- 188 < 8 < 8 < 25 < 10 10/19/20 1378 +/- 216 < 9 < 7 < 28 < 10 11/03/20 1167 +/- 187 < 8 < 7 < 29 < 9 11/17/20 1343 +/- 197 < 9 < 7 < 30 < 10 12/11/20 1176 +/- 167 < 8 < 8 < 38 < 10 MEAN +/- 2 STD DEV 1230 +/- 211 - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-13

Table C-VII.2 CONCENTRATIONS OF GAMMA EMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD K-40 Cs-134 Cs-137 Ba-140 La-140 23F1 01/14/20 1402 +/- 158 < 7 < 7 < 22 < 9 02/10/20 1463 +/- 163 < 6 < 7 < 26 < 9 03/10/20 919 +/- 136 < 7 < 6 < 23 < 7 04/06/20 1318 +/- 132 < 6 < 6 < 20 < 6 04/21/20 1361 +/- 171 < 7 < 7 < 22 < 7 05/05/20 1083 +/- 188 < 8 < 7 < 29 < 9 05/19/20 1242 +/- 166 < 7 < 7 < 27 < 7 06/01/20 1273 +/- 158 < 9 < 9 < 32 < 10 06/16/20 1166 +/- 181 < 7 < 6 < 26 < 9 06/29/20 1321 +/- 157 < 7 < 7 < 27 < 7 07/14/20 1268 +/- 199 < 9 < 9 < 26 < 5 07/27/20 1170 +/- 207 < 8 < 7 < 27 < 9 08/10/20 1244 +/- 192 < 10 < 9 < 29 < 9 08/24/20 1302 +/- 157 < 8 < 8 < 29 < 10 09/08/20 1376 +/- 185 < 10 < 9 < 33 < 3 09/21/20 1030 +/- 188 < 11 < 9 < 36 < 7 10/06/20 1293 +/- 151 < 9 < 8 < 29 < 9 10/19/20 1199 +/- 185 < 8 < 8 < 28 < 11 11/03/20 1344 +/- 174 < 8 < 9 < 29 < 9 11/17/20 1306 +/- 175 < 8 < 7 < 30 < 6 12/11/20 1406 +/- 211 < 7 < 9 < 40 < 8 MEAN +/- 2 STD DEV 1261 +/- 264 - - - -

25C1 01/14/20 1146 +/- 150 < 9 < 6 < 30 < 8 02/10/20 1145 +/- 155 < 8 < 7 < 26 < 8 03/10/20 1325 +/- 146 < 6 < 7 < 22 < 5 04/06/20 1225 +/- 204 < 8 < 8 < 31 < 8 04/21/20 983 +/- 152 < 7 < 7 < 27 < 10 05/05/20 1433 +/- 202 < 10 < 10 < 35 < 11 05/19/20 890 +/- 129 < 6 < 5 < 20 < 6 06/02/20 1330 +/- 195 < 10 < 8 < 29 < 10 06/16/20 1664 +/- 224 < 9 < 8 < 40 < 9 06/29/20 1441 +/- 179 < 7 < 7 < 29 < 7 07/14/20 1223 +/- 169 < 8 < 8 < 26 < 6 07/27/20 1389 +/- 189 < 9 < 8 < 32 < 14 08/10/20 1154 +/- 164 < 9 < 8 < 27 < 10 08/24/20 1183 +/- 181 < 9 < 9 < 28 < 7 09/08/20 1466 +/- 164 < 6 < 7 < 25 < 7 09/21/20 1480 +/- 176 < 10 < 8 < 36 < 8 10/06/20 1310 +/- 178 < 11 < 7 < 29 < 9 10/19/20 1198 +/- 182 < 8 < 8 < 27 < 10 11/03/20 1312 +/- 186 < 10 < 7 < 29 < 12 11/17/20 1188 +/- 206 < 10 < 10 < 37 < 9 12/07/20 1283 +/- 158 < 9 < 9 < 32 < 10 MEAN +/- 2 STD DEV 1275 +/- 350 - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-14

TABLE C-VIII.1 CONCENTRATIONS OF GAMMA EMITTERS IN BROAD LEAFY VEGETATION SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION SITE PERIOD Be-7 K-40 Mn-54 Co-58 Co-60 I-131 Cs-134 Cs-137 Ra-226 Th-228 Th-232 11S3 06/16/20 Kale Leaves < 235 5037 +/- 640 < 28 < 29 < 24 < 28 < 33 < 19 < 603 101 +/- 47 < 115 06/16/20 Cabbage Leaves < 240 4477 +/- 668 < 27 < 31 < 31 < 29 < 23 < 26 < 551 87 +/- 37 < 98 06/16/20 Swiss Chard Leaves < 238 6858 +/- 648 < 28 < 25 < 33 < 27 < 30 < 27 < 511 97 +/- 40 < 120 07/09/20 Kale Leaves < 339 4234 +/- 648 < 33 < 29 < 44 < 38 < 34 < 41 < 689 < 56 < 132 07/09/20 Swiss Chard Leaves 342 +/- 305 8133 +/- 899 < 24 < 27 < 38 < 34 < 26 < 27 < 696 < 52 < 126 07/09/20 Brussels Sprouts Leaves < 307 3682 +/- 641 < 29 < 33 < 38 < 36 < 25 < 22 < 579 < 47 < 109 08/11/20 Cabbage Leaves 531 +/- 233 3197 +/- 553 < 26 < 21 < 21 < 26 < 31 < 30 < 629 < 50 < 117 08/11/20 Collard Leaves 908 +/- 317 3929 +/- 608 < 36 < 26 < 33 < 29 < 29 < 27 < 618 48 +/- 42 < 114 08/11/20 Swiss Chard Leaves 872 +/- 329 7718 +/- 792 < 29 < 35 < 46 < 34 < 31 < 26 < 653 < 46 < 119 09/14/20 Swiss Chard Leaves < 206 4476 +/- 581 < 24 < 27 < 30 < 30 < 34 < 26 < 653 < 52 < 105 09/14/20 Cucumber Leaves < 346 4243 +/- 682 < 31 < 30 < 37 < 35 < 26 < 36 < 691 < 66 < 119 MEAN +/- 2 STD DEV 663 +/- 546 5089 +/- 3371 - - - - - - - 83 +/- 49 -

13S3 06/16/20 Kale Leaves < 329 4199 +/- 799 < 29 < 36 < 28 < 32 < 37 < 45 < 951 111 +/- 53 < 150 06/16/20 Swiss Chard Leaves < 376 7174 +/- 971 < 37 < 41 < 51 < 35 < 48 < 44 < 814 117 +/- 56 < 173 06/16/20 Brussels Sprouts Leaves < 357 3190 +/- 730 < 46 < 42 < 50 < 50 < 55 < 52 < 1286 122 +/- 89 < 216 07/09/20 Kale Leaves 339 +/- 190 3786 +/- 518 < 24 < 22 < 27 < 31 < 27 < 23 1084 +/- 540 < 42 < 90 07/09/20 Swiss Chard Leaves 714 +/- 177 6688 +/- 569 < 19 < 20 < 24 < 18 < 20 < 24 < 433 37 +/- 27 < 90 C-15 07/09/20 Brussels Sprouts Leaves < 216 4112 +/- 425 < 22 < 22 < 24 < 23 < 27 < 23 1273 +/- 562 50 +/- 34 < 95 08/11/20 Kale Leaves 742 +/- 229 2722 +/- 496 < 23 < 22 < 24 < 25 < 25 < 30 < 719 79 +/- 40 < 105 08/11/20 Cabbage Leaves 703 +/- 313 3432 +/- 560 < 32 < 24 < 31 < 32 < 38 < 36 < 846 < 73 < 133 08/11/20 Swiss Chard Leaves 492 +/- 334 6347 +/- 739 < 29 < 29 < 39 < 27 < 30 < 29 < 636 56 +/- 56 < 133 09/14/20 Swiss Chard Leaves < 272 6064 +/- 727 < 30 < 24 < 26 < 33 < 31 < 24 < 699 < 52 < 121 MEAN +/- 2 STD DEV 598 +/- 351 4771 +/- 3254 - - - - - - 1179 +/- 267 82 +/- 70 -

31G1 06/16/20 Cabbage Leaves < 321 5446 +/- 806 < 37 < 39 < 33 < 37 < 41 < 40 < 984 363 +/- 79 < 143 06/16/20 Pepper Leaves < 446 5567 +/- 812 < 33 < 41 < 46 < 39 < 43 < 36 < 981 580 +/- 100 < 160 06/16/20 Corn Leaves < 452 5882 +/- 850 < 44 < 36 < 46 < 41 < 43 < 42 < 908 626 +/- 88 < 138 07/09/20 Zucchini Leaves 904 +/- 170 2817 +/- 477 < 18 < 18 < 19 < 21 < 21 < 21 < 439 123 +/- 27 < 88 07/09/20 Yellow Squash Leaves 1989 +/- 343 6358 +/- 712 < 27 < 21 < 39 < 36 < 35 < 32 < 730 < 62 < 121 07/09/20 Corn Leaves 2570 +/- 401 5062 +/- 704 < 32 < 27 < 29 < 45 < 42 < 29 < 801 < 65.5 < 118 08/11/20 Yellow Squash Leaves 1583 +/- 278 4219 +/- 561 < 26 < 21 < 22 < 26 < 27 < 22 < 661 105 +/- 44 < 125 08/11/20 Cucumber Leaves 947 +/- 237 3530 +/- 612 < 26 < 30 < 36 < 23 < 29 < 26 < 568 136 +/- 56 < 153 08/11/20 Watermelon Leaves 1307 +/- 261 2681 +/- 457 < 25 < 29 < 33 < 24 < 34 < 30 < 615 103 +/- 50 < 103 09/14/20 Yellow Squash Leaves < 330 3715 +/- 580 < 29 < 28 < 23 < 30 < 33 < 31 < 625 < 62 < 128 09/14/20 Cucumber Leaves 614 +/- 209 3615 +/- 546 < 22 < 24 < 32 < 25 < 18 < 29 < 420 < 41 < 99 MEAN +/- 2 STD DEV 1416 +/- 1373 4445 +/- 2549 - - - - - - - 291 +/- 464 -

THE MEAN AND 2-STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES

Table C-IX.1 QUARTERLY DLR RESULTS FOR LIMERICK GENERATING STATION, 2020 Normalized BA + Annual Facility Annual Facility Qtr 1 Qtr 2 Qtr 3 Qtr 4 Location Annual Dose, MA BA(1) Dose, FA Dose, (mrem) (mrem) (mrem) (mrem) MDDA(2)

(mrem/yr) (mrem) F A >10 mrem 10E1 17.7 18.7 19.0 18.4 73.8 71.0 82.7 ND No 10F3 18.6 18.7 17.9 19.0 74.1 69.7 81.4 ND No 10S3 18.3 19.2 18.8 19.3 75.5 70.9 82.6 ND No 11S1 20.6 22.5 21.5 20.9 85.4 83.1 94.8 ND No 13C1 13.1 13.3 13.2 12.5 52.1 49.8 61.5 ND No 130 18.4 18.0 18.7 19.6 74.7 70.1 81.8 ND No 13S2 26.2 25.4 27.4 26.1 105.2 112.1 123.8 ND No 14S1 16.0 17.6 15.9 16.7 66.2 63.2 74.9 ND No 15D1 18.3 20.0 19.1 19.2 76.6 72.5 84.2 ND No 16F1 17.5 17.6 18.7 18.8 72.6 73.4 85.1 ND No 17B1 17.1 17.2 17.2 17.6 69.1 66.8 78.5 ND No 18S2 19.0 19.8 18.9 19.5 77.2 78.4 90.1 ND No 19D1 16.4 17.0 17.0 16.6 67.1 66.3 78.0 ND No 20D1 14.8 15.7 15.5 16.0 62.0 63.0 74.7 ND No 20F1 17.6 17.9 17.5 16.5 69.5 67.5 79.2 ND No 21S2 16.3 16.6 16.6 17.1 66.6 64.1 75.8 ND No 23S2 16.3 16.6 16.8 16.0 65.7 63.9 75.6 ND No 24D1 14.6 15.2 15.1 15.4 60.2 59.7 71.4 ND No 25D1 14.0 15.9 14.4 15.0 59.3 56.5 68.2 ND No 25S2 15.0 15.6 15.9 15.8 62.3 58.1 69.8 ND No 26S3 14.1 16.4 15.7 16.7 62.9 60.4 72.1 ND No 28D2 15.6 16.0 17.0 17.1 65.7 63.5 75.2 ND No 29E1 17.0 16.8 16.5 16.7 67.0 62.3 74.0 ND No 29S1 15.9 15.5 15.5 16.3 63.3 61.4 73.1 ND No 2E1 17.9 19.0 20.2 19.4 76.4 71.9 83.6 ND No 31D1 20.8 21.3 20.5 21.8 84.5 83.0 94.7 ND No 31D2 19.6 19.6 19.1 19.4 77.6 71.2 82.9 ND No 31S1 19.3 18.3 18.8 19.9 76.3 71.6 83.3 ND No 34E1 17.4 17.7 18.0 17.6 70.7 67.0 78.7 ND No 34S2 14.3 15.8 17.4 18.2 65.7 71.6 83.3 ND No 36D1 15.0 14.5 15.7 15.7 60.9 62.1 73.8 ND No 36S2 17.6 18.1 19.4 18.4 73.5 73.4 85.1 ND No 3S1 16.4 18.7 17.9 18.7 71.6 70.1 81.8 ND No 4E1 13.3 14.0 13.5 13.3 54.1 51.4 63.1 ND No 5H1 21.5 22.5 23.3 21.5 88.8 86.3 98.0 ND No 5S1 17.8 20.5 19.8 20.0 78.1 80.0 91.7 ND No 6C1 17.3 17.3 18.7 18.3 71.6 69.5 81.2 ND No 7E1 18.5 20.1 19.5 19.5 77.5 74.6 86.3 ND No 7S1 18.0 17.6 18.7 18.4 72.7 73.1 84.8 ND No 9C1 17.6 19.1 17.3 17.6 71.6 68.1 79.8 ND No (1)

Baseline background dose (BBA): The estimated mean background radiation dose at each field monitoring location annually based on historical measurements, excluding any dose contribution from the monitored facility (2)

Minimum differential dose (MDDA): The smallest amount of facility related dose at each monitored location annually above the baseline background dose that can be reliably detected by an environmental dosimetry system C-16

FIGURE C-1 MEAN MONTHLY TOTAL GROSS BETA CONCENTRATIONS IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LGS, 1982 - 2020 12 10 8

C-17 6 pCi/liter 4

2 CONTROL INDICATOR 0

82 91 01 10 20 YEAR Note: 2005 analysis changed from Insoluble & Soluble to Total Gross Beta LGS CRITICALITY UNIT NO. 1: 12/22/84 LGS CHANGED TO TOTAL GROSS BETA AT THE BEGINNING OF 2005.

UNIT NO. 2: 08/11/89 PREVIOUS DATA INCLUDED SUMMATION OF LESS THAN VALUES.

FIGURE C-2 MEAN MONTHLY GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LGS, 1982 - 2020 150 Group I 135 Group II Chernobyl Group III 120 105 90 C-18 75 LGS CRITICALITY UNIT NO. 1: 12/22/84 60 UNIT NO. 2: 08/11/89 E-03 pCi/cubic meter 45 30 15 0

82 94 07 20 YEAR

FIGURE C-3 MEAN WEEKLY GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LGS, 2020 50 GROUP I GROUP II GROUP III 40 30 C-19 E-03 pCi/cubic meter 20 10 0

4 8 12 16 20 24 28 32 36 40 44 48 52 WEEK NO.

Intentionally left blank APPENDIX D DATA TABLES AND FIGURES COMPARISON LABORATORY

Intentionally left blank TABLE D-I.1 CONCENTRATIONS OF TOTAL GROSS BETA IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 16C2 12/30/19 - 02/03/20 2.0 +/- 0.7 02/03/20 - 03/02/20 1.9 +/- 0.7 03/02/20 - 03/30/20 1.4 +/- 0.6 03/30/20 - 04/27/20 2.3 +/- 0.7 04/27/20 - 06/02/20 2.2 +/- 0.7 06/02/20 - 06/29/20 1.7 +/- 0.7 06/29/20 - 07/28/20 4.5 +/- 0.8 07/28/20 - 08/31/20 1.9 +/- 0.6 08/31/20 - 09/29/20 3.8 +/- 0.8 09/29/20 - 11/03/20 2.1 +/- 0.7 11/03/20 - 12/01/20 2.0 +/- 0.7 12/01/20 - 12/28/20 2.6 +/- 0.8 MEAN +/- 2 STD DEV 2.4 +/- 1.8 TABLE D-I.2 CONCENTRATIONS OF I-131 IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 16C2 12/30/19 - 02/03/20 < 1.0 02/03/20 - 03/02/20 < 0.7 03/02/20 - 03/30/20 < 0.6 03/30/20 - 04/27/20 < 0.8 04/27/20 - 06/02/20 < 0.4 06/02/20 - 06/29/20 < 0.8 06/29/20 - 07/28/20 < 0.6 07/28/20 - 08/31/20 < 0.6 08/31/20 - 09/29/20 < 0.6 09/29/20 - 11/03/20 < 1.0 11/03/20 - 12/01/20 < 0.7 12/01/20 - 12/28/20 < 0.8 MEAN -

TABLE D-I.3 CONCENTRATIONS OF TRITIUM IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD 16C2 12/30/19 - 03/30/20 < 146 03/30/20 - 06/29/20 < 139 06/29/20 - 09/29/20 < 172 09/29/20 - 12/28/20 < 121 MEAN -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES D-1

TABLE D-I.4 CONCENTRATIONS OF GAMMA EMITTERS IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 16C2 12/30/19 - 02/03/20 < 4 < 4 < 8 < 4 < 9 < 5 < 7 < 9 < 4 < 4 < 22 < 7 02/03/20 - 03/02/20 < 3 < 3 < 7 < 3 < 6 < 4 < 6 < 6 < 3 < 3 < 17 < 6 03/02/20 - 03/30/20 < 7 < 5 < 12 < 6 < 10 < 6 < 10 < 7 < 6 < 6 < 25 < 9 03/30/20 - 04/27/20 < 4 < 4 < 9 < 4 < 7 < 4 < 7 < 8 < 4 < 4 < 19 < 8 04/27/20 - 06/02/20 < 7 < 6 < 11 < 6 < 10 < 6 < 10 < 7 < 5 < 6 < 24 < 13 06/02/20 - 06/29/20 < 3 < 3 < 7 < 3 < 6 < 4 < 6 < 8 < 3 < 4 < 19 < 6 06/29/20 - 07/28/20 < 4 < 4 < 8 < 4 < 8 < 5 < 7 < 6 < 4 < 4 < 18 < 7 07/28/20 - 08/31/20 < 5 < 4 < 9 < 5 < 12 < 5 < 8 < 6 < 5 < 5 < 19 < 7 08/31/20 - 09/29/20 < 4 < 4 < 8 < 4 < 9 < 5 < 7 < 4 < 4 < 4 < 16 < 7 09/29/20 - 11/03/20 < 5 < 5 < 10 < 5 < 11 < 6 < 9 < 10 < 5 < 6 < 34 < 9 11/03/20 - 12/01/20 < 4 < 3 < 7 < 5 < 9 < 5 < 7 < 8 < 4 < 4 < 17 < 6 12/01/20 - 12/28/20 < 4 < 4 < 8 < 4 < 9 < 4 < 7 8 7 < 4 < 5 < 19 < 7 MEAN - - - - - - - - - - - -

D-2

TABLE D-II.1 CONCENTRATIONS OF GROSS BETA IN AIR PARTICULATE AND I-131 IN AIR IODINE SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF E-03 PCI/CU METER +/- 2 SIGMA COLLECTION 11S2 11S2 PERIOD GROSS BETA I-131 12/30/19 - 01/06/20 16 +/- 2 < 9 01/06/20 - 01/13/20 10 +/- 2 < 11 01/13/20 - 01/21/20 23 +/- 2 < 11 01/21/20 - 01/27/20 16 +/- 2 < 23 01/27/20 - 02/03/20 12 +/- 2 < 11 02/03/20 - 02/10/20 14 +/- 2 < 13 02/10/20 - 02/17/20 19 +/- 2 < 13 02/17/20 - 02/24/20 30 +/- 2 < 12 02/24/20 - 03/02/20 21 +/- 2 < 16 03/02/20 - 03/09/20 17 +/- 2 < 10 03/09/20 - 03/16/20 19 +/- 2 < 11 03/16/20 - 03/23/20 23 +/- 2 < 19 03/23/20 - 03/30/20 11 +/- 2 < 17 03/30/20 - 04/06/20 12 +/- 1 < 20 04/06/20 - 04/13/20 19 +/- 1 < 20 04/13/20 - 04/20/20 24 +/- 1 < 27 04/20/20 - 04/27/20 18 +/- 1 < 14 04/27/20 - 05/04/20 16 +/- 2 < 17 05/04/20 - 05/11/20 15 +/- 2 < 25 05/11/20 - 05/18/20 21 +/- 2 < 19 05/18/20 - 05/26/20 14 +/- 2 < 13 05/26/20 - 06/02/20 15 +/- 2 < 17 06/02/20 - 06/08/20 20 +/- 2 < 30 06/08/20 - 06/15/20 13 +/- 2 < 12 06/15/20 - 06/22/20 12 +/- 2 < 21 06/22/20 - 06/29/20 22 +/- 2 < 17 06/29/20 - 07/06/20 18 +/- 2 < 23 07/06/20 - 07/13/20 19 +/- 2 < 18 07/13/20 - 07/20/20 21 +/- 2 < 11 07/20/20 - 07/28/20 25 +/- 2 < 14 07/28/20 - 08/04/20 28 +/- 2 < 18 08/04/20 - 08/10/20 24 +/- 2 < 23 08/10/20 - 08/17/20 32 +/- 2 < 23 08/17/20 - 08/24/20 25 +/- 2 < 18 08/24/20 - 08/31/20 23 +/- 2 < 22 08/31/20 - 09/08/20 23 +/- 2 < 13 09/08/20 - 09/14/20 17 +/- 2 < 23 09/14/20 - 09/21/20 20 +/- 2 < 16 09/21/20 - 09/29/20 38 +/- 2 < 15 09/29/20 - 10/05/20 18 +/- 2 < 27 10/05/20 - 10/12/20 29 +/- 2 < 23 10/12/20 - 10/19/20 16 +/- 2 < 15 10/19/20 - 10/26/20 14 +/- 2 < 19 10/26/20 - 11/03/20 18 +/- 2 < 15 11/03/20 - 11/10/20 44 +/- 3 < 43 11/10/20 - 11/16/20 21 +/- 2 < 17 11/16/20 - 11/23/20 22 +/- 2 < 24 11/23/20 - 12/01/20 28 +/- 3 < 23 12/01/20 - 12/07/20 18 +/- 2 < 17 12/07/20 - 12/14/20 22 +/- 3 < 49 12/14/20 - 12/21/20 (1) (1) 12/21/20 - 12/28/20 27 +/- 2 < 15 MEAN +/- 2 STD DEV 20 +/- 13 -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUE D-3

TABLE D-II.2 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF E-03 PCI/CU METER +/- 2 SIGMA COLLECTION SITE PERIOD Be-7 Mn-54 Co-58 Co-60 Cs-134 Cs-137 11S2 12/30/19 - 03/30/20 70 +/- 16 < 1.9 < 1.8 < 1.0 < 1.5 < 1.4 03/30/20 - 06/29/20 82 +/- 16 < 1.6 < 1.9 < 1.6 < 1.2 < 1.5 06/29/20 - 09/29/20 76 +/- 16 < 1.8 < 1.6 < 1.5 < 1.2 < 1.4 09/29/20 - 12/28/20 50 +/- 11 < 1.2 < 1.3 < 1.2 < 1.3 < 1.2 MEAN +/- 2 STD DEV 69 +/- 28 - - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES D-4

TABLE D-III.1 CONCENTRATIONS OF I-131 BY CHEMICAL SEPARATION AND GAMMA EMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD I-131 K-40 Cs-134 Cs-137 Ba-140 La-140 19B1 01/14/20 < 0.5 1330 +/- 84 < 3 < 4 < 12 < 4 04/06/20 < 0.8 1110 +/- 95 < 4 < 5 < 21 < 7 07/14/20 < 0.6 1300 +/- 102 < 4 < 5 < 20 < 6 10/06/20 < 0.8 1280 +/- 100 < 4 < 4 < 21 < 6 MEAN +/- 2 STD DEV - 1255 +/- 198 - - - -

25C1 01/14/20 < 0.4 1160 +/- 85 < 4 < 5 < 15 < 5 04/06/20 < 0.6 1270 +/- 101 < 5 < 5 < 21 < 7 07/14/20 < 0.8 1410 +/- 108 < 5 < 6 < 21 < 8 10/06/20 < 0.7 1370 +/- 105 < 4 < 5 < 24 < 7 MEAN +/- 2 STD DEV - 1303 +/- 224 - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES D-5

FIGURE D-1 COMPARISON OF MONTHLY TOTAL GROSS BETA CONCENTRATIONS IN DRINKING WATER SAMPLES SPLIT BETWEEN EIS AND TBE, 2020 10.0 9.0 EIS TBE 8.0 7.0 6.0 D-6 5.0 pCi/liter 4.0 3.0 2.0 1.0 0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec MONTH

FIGURE D-2 COMPARISON OF WEEKLY GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED FROM LGS COLLOCATED LOCATIONS 11S1 AND 11S2, 2020 60 11S2 - EIS 11S1 - TBE 50 40 D-7 30 E-03 pCi/cubic meter 20 10 0

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 WEEK NO.

Intentionally left blank APPENDIX E INTER-LABORATORY COMPARISON PROGRAM

Analytics Environmental Radioactivity Cross Check Program 7DEOH( Teledyne Brown Engineering Environmental Services Identification Known Ratio of TBE to Month/Year Matrix Nuclide Units TBE Value Evaluation (b)

Number Value (a) Known Result September 2020 E13247 Milk Sr-89 pCi/L 62.8 95.4 0.66 N(1)

Sr-90 pCi/L 12.0 12.8 0.94 A E13248 Milk Ce-141 pCi/L 156 150 1.04 A Co-58 pCi/L 172 180 0.96 A Co-60 pCi/L 369 379 0.97 A Cr-51 pCi/L 372 372 1.00 A Cs-134 pCi/L 171 200 0.85 A Cs-137 pCi/L 241 250 0.96 A Fe-59 pCi/L 217 200 1.08 A I-131 pCi/L 84.6 95.0 0.89 A Mn-54 pCi/L 175 180 0.97 A Zn-65 pCi/L 252 270 0.93 A E13249 Charcoal I-131 pCi 70.2 75.8 0.93 A E13250 AP Ce-141 pCi 101 101 1.00 A Co-58 pCi 111 120 0.92 A Co-60 pCi 249 254 0.98 A Cr-51 pCi 287 249 1.15 A Cs-134 pCi 114 134 0.85 A Cs-137 pCi 159 168 0.95 A Fe-59 pCi 127 134 0.95 A Mn-54 pCi 114 121 0.94 A Zn-65 pCi 168 181 0.93 A E13251 Soil Ce-141 pCi/g 0.241 0.191 1.26 W Co-58 pCi/g 0.211 0.228 0.93 A Co-60 pCi/g 0.466 0.481 0.97 A Cr-51 pCi/g 0.450 0.472 0.95 A Cs-134 pCi/g 0.273 0.254 1.07 A Cs-137 pCi/g 0.370 0.390 0.95 A Fe-59 pCi/g 0.233 0.254 0.92 A Mn-54 pCi/g 0.217 0.229 0.95 A Zn-65 pCi/g 0.368 0.343 1.07 A E13252 AP Sr-89 pCi 79.9 100.0 0.80 A Sr-90 pCi 12.1 13.4 0.90 A (a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) Analytics evaluation based on TBE internal QC limits:

A = Acceptable - reported result falls within ratio limits of 0.80-1.20 W = Acceptable with warning - reported result falls within 0.70-0.80 or 1.20-1.30 N = Not Acceptable - reported result falls outside the ratio limits of < 0.70 and > 1.30 (1) See NCR 20-19 (Page 1 of 2)

Analytics Environmental Radioactivity Cross Check Program 7DEOH( Teledyne Brown Engineering Environmental Services Identification Known Ratio of TBE to Month/Year Matrix Nuclide Units TBE Value Evaluation (b)

Number Value (a) Known Result December 2020 E13254 Milk Sr-89 pCi/L 82.2 89.7 0.92 A Sr-90 pCi/L 12.4 13.0 0.96 A E13255 Milk Ce-141 pCi/L 91.1 100 0.91 A Co-58 pCi/L 77.5 84.3 0.92 A Co-60 pCi/L 147 152 0.97 A Cr-51 pCi/L 259 253 1.02 A Cs-134 pCi/L 97.1 108 0.90 A Cs-137 pCi/L 117 127 0.92 A Fe-59 pCi/L 114 112 1.02 A I-131 pCi/L 84.3 91.9 0.92 A Mn-54 pCi/L 137 143 0.96 A Zn-65 pCi/L 175 190 0.92 A E13256 Charcoal I-131 pCi 70.2 78.2 0.90 A E13257A AP Ce-141 pCi 67.4 74.6 0.90 A Co-58 pCi 57.9 62.9 0.92 A Co-60 pCi 108 113 0.95 A Cr-51 pCi 162 189 0.86 A Cs-134 pCi 68.1 80.4 0.85 A Cs-137 pCi 82.4 95.0 0.87 A Fe-59 pCi 80.5 83.7 0.96 A Mn-54 pCi 102 107 0.95 A Zn-65 pCi 115 142 0.81 A E13258 Soil Ce-141 pCi/g 0.167 0.170 0.98 A Co-58 pCi/g 0.125 0.143 0.87 A Co-60 pCi/g 0.245 0.257 0.95 A Cr-51 pCi/g 0.393 0.429 0.92 A Cs-134 pCi/g 0.147 0.183 0.80 A Cs-137 pCi/g 0.260 0.288 0.90 A Fe-59 pCi/g 0.199 0.190 1.05 A Mn-54 pCi/g 0.229 0.243 0.94 A Zn-65 pCi/g 0.320 0.322 0.99 A E13259 AP Sr-89 pCi 85.0 78.6 1.08 A Sr-90 pCi 13.1 11.4 1.15 A (a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) Analytics evaluation based on TBE internal QC limits:

A = Acceptable - reported result falls within ratio limits of 0.80-1.20 W = Acceptable with warning - reported result falls within 0.70-0.80 or 1.20-1.30 N = Not Acceptable - reported result falls outside the ratio limits of < 0.70 and > 1.30 (Page 2 of 2)

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ERA Environmental Radioactivity Cross Check Program 7DEOH( Teledyne Brown Engineering Environmental Services Identification Known Acceptance Month/Year Matrix Nuclide Units TBE Value Evaluation (b)

Number Value (a) Limits March 2020 MRAD-32 Water Am-241 pCi/L 52.5 45.3 31.1 - 57.9 A Fe-55 pCi/L 155 152 89.3 - 221 A Pu-238 pCi/L 34.0 36.4 21.9 - 47.2 A Pu-239 pCi/L 30.9 33.6 20.8 - 41.4 A April 2020 RAD-121 Water Ba-133 pCi/L 41.8 41.8 34.0- 46.7 A Cs-134 pCi/L 42.9 46.3 37.1 - 50.9 A Cs-137 pCi/L 226 234 211 - 259 A Co-60 pCi/L 52.4 50.3 45.3 - 57.9 A Zn-65 pCi/L 83.3 86.8 78.1 - 104 A GR-A pCi/L 20.1 23.6 11.9 - 31.6 A GR-B pCi/L 45.6 60.5 41.7 - 67.2 A U-Nat pCi/L 18.45 18.6 14.9 - 20.9 A H-3 pCi/L 14200 14100 12300 - 15500 A Sr-89 pCi/L 58.0 60.1 48.3 - 67.9 A Sr-90 pCi/L 34.1 44.7 33.0 - 51.2 A I-131 pCi/L 27.4 28.9 24.1 - 33.8 A September 2020 MRAD-33 Soil Sr-90 pCi/Kg 4360 4980 1550 - 7760 A AP Fe-55 pCi/Filter 189 407 149 - 649 A U-234 pCi/Filter 17.9 18.3 13.6 - 21.4 A U-238 pCi/Filter 19.1 18.1 13.7 - 21.6 A Water Am-241 pCi/L 160 176 121 - 225 A Fe-55 pCi/L 299 298 175 - 433 A Pu-238 pCi/L 200 191 115 - 247 A Pu-239 pCi/L 105 100 61.9 - 123 A October 2020 RAD-123 Water Ba-133 pCi/L 37.1 37.0 29.8 - 41.6 A Cs-134 pCi/L 50.6 52.7 42.5 - 58.0 A Cs-137 pCi/L 131 131 118 - 146 A Co-60 pCi/L 62.9 60.5 54.4 - 69.1 A Zn-65 pCi/L 167 162 146 - 191 A GR-A pCi/L 40.0 26.2 13.3 - 34.7 N(1)

GR-B pCi/L 47.5 69.1 48.0 - 76.0 N(1)

U-Nat pCi/L 17.2 20.3 16.3 - 22.7 A H-3 pCi/L 23800 23200 20,300 - 25,500 A Sr-89 pCi/L 41.1 43.3 33.4 - 50.5 A Sr-90 pCi/L 28.5 30.2 22.0 - 35.0 A I-131 pCi/L 22.9 28.2 23.5 - 33.1 N(2)

November 2020 QR111920K Water GR-A pCi/L 50.7 52.4 27.3 - 65.6 A GR-B pCi/L 24.9 24.3 15.0 - 32.3 A (a) The ERA known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation.

(b) ERA evaluation:

A = Acceptable - Reported value falls within the Acceptance Limits N = Not Acceptable - Reported value falls outside of the Acceptance Limits (1) See NCR 20-18 (2) See NCR 20-17 (Page 1 of 1)

TABLE E.4 Analytics Environmental Radioactivity Cross Check Program Exelon Industrial Services (2020)

EIS Identification Known Ratio of Analytics Month/Year Matrix Nuclide Units Reported Evaluation (b)

Number Value (a) to EIS Result Value June 2020 E13065 AP Ce-141 pCi/Filter 71.5 75.5 95 Pass Detector 2 Co-58 pCi/Filter 60.7 65.4 93 Pass Co-60 pCi/Filter 125 127 98 Pass Cr-51 pCi/Filter 115 167 69 Pass Cs-134 pCi/Filter 82.9 95.2 87 Pass Cs-137 pCi/Filter 64.0 67.5 95 Pass Fe-59 pCi/Filter 65.8 65.7 100 Pass Mn-54 pCi/Filter 87.3 87.0 100 Pass Zn-65 pCi/Filter 136 146 93 Pass E13065 AP Ce-141 pCi/Filter 68.0 75.5 90 Pass Detector 3 Co-58 pCi/Filter 67.3 65.4 103 Pass Co-60 pCi/Filter 125 127 99 Pass Cr-51 pCi/Filter 135 167 81 Pass Cs-134 pCi/Filter 83.9 95.2 88 Pass Cs-137 pCi/Filter 70.9 67.5 105 Pass Fe-59 pCi/Filter 72.4 65.7 110 Pass Mn-54 pCi/Filter 91.8 87.0 106 Pass Zn-65 pCi/Filter 154 146 106 Pass E13065 AP Ce-141 pCi/Filter 82.8 75.5 110 Pass Detector 4 Co-58 pCi/Filter 55.0 65.4 84 Pass Co-60 pCi/Filter 124 127 98 Pass Cr-51 pCi/Filter 159 167 95 Pass Cs-134 pCi/Filter 75.8 95.2 80 Pass Cs-137 pCi/Filter 64.2 67.5 95 Pass Fe-59 pCi/Filter 82.9 65.7 126 Pass Mn-54 pCi/Filter 88.3 87.0 102 Pass Zn-65 pCi/Filter 153 146 105 Pass E13065 AP Ce-141 pCi/Filter 79.4 75.5 105 Pass Detector 5 Co-58 pCi/Filter 62.1 65.4 95 Pass Co-60 pCi/Filter 136 127 107 Pass Cr-51 pCi/Filter 179 167 107 Pass Cs-134 pCi/Filter 81.4 95.2 86 Pass Cs-137 pCi/Filter 71.8 67.5 106 Pass Fe-59 pCi/Filter 71.7 65.7 109 Pass Mn-54 pCi/Filter 94.1 87.0 108 Pass Zn-65 pCi/Filter 152 146 104 Pass June 2020 E13062 AP I-131 pCi/Filter 82.5 91.7 90 Pass Detectors I-131 pCi/Filter 87.6 91.7 96 Pass 2,3,4,5 I-131 pCi/Filter 88.1 91.7 96 Pass I-131 pCi/Filter 86.2 91.7 94 Pass E13063 Water Gr-B pCi/L 273 272 100 Pass E13060 Milk I-131 pCi/L 80.8 81.5 99 Pass Detector 2 Ce-141 pCi/L 107 116 92 Pass Co-58 pCi/L 107 100 107 Pass Co-60 pCi/L 200 195 103 Pass Cr-51 pCi/L 223 256 87 Pass Cs-134 pCi/L 142 146 97 Pass Cs-137 pCi/L 97.9 104 94 Pass Fe-59 pCi/L 96.0 101 95 Pass Mn-54 pCi/L 154 134 115 Pass Zn-65 pCi/L 225 225 100 Pass (a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) Analytics evaluation based on EIS internal QC limits in accordance with the NRC Resolution Test criteria (Page 1 of 3)

TABLE E.4 Analytics Environmental Radioactivity Cross Check Program Exelon Industrial Services (2020)

EIS Identification Known Ratio of Analytics Month/Year Matrix Nuclide Units Reported Evaluation (b)

Number Value (a) to EIS Result Value E13060 Milk I-131 pCi/L 81.2 81.5 100 Pass Detector 3 Ce-141 pCi/L 106 116 91 Pass Co-58 pCi/L 101 100 101 Pass Co-60 pCi/L 195 195 100 Pass Cr-51 pCi/L 250 256 98 Pass Cs-134 pCi/L 131 146 90 Pass Cs-137 pCi/L 102 104 98 Pass Fe-59 pCi/L 99.1 101 98 Pass Mn-54 pCi/L 133 134 99 Pass Zn-65 pCi/L 189 225 84 Pass E13060 Milk I-131 pCi/L 71.4 81.5 88 Pass Detector 4 Ce-141 pCi/L 114 116 98 Pass Co-58 pCi/L 99.2 100 99 Pass Co-60 pCi/L 199 195 102 Pass Cr-51 pCi/L 251 256 98 Pass Cs-134 pCi/L 125 146 86 Pass Cs-137 pCi/L 98.9 104 95 Pass Fe-59 pCi/L 104 101 103 Pass Mn-54 pCi/L 124 134 92 Pass Zn-65 pCi/L 211 225 94 Pass E13060 Milk I-131 pCi/L 87.3 81.5 107 Pass Detector 5 Ce-141 pCi/L 118 116 102 Pass Co-58 pCi/L 94.9 100 95 Pass Co-60 pCi/L 181 195 93 Pass Cr-51 pCi/L 231 256 90 Pass Cs-134 pCi/L 128 146 88 Pass Cs-137 pCi/L 101 104 97 Pass Fe-59 pCi/L 106 101 105 Pass Mn-54 pCi/L 130 134 97 Pass Zn-65 pCi/L 200 225 89 Pass E13064 Water I-131 pCi/L 63.9 80.5 79 Pass Detector 2 Ce-141 pCi/L 116 117 99 Pass Co-58 pCi/L 91.4 102 90 Pass Co-60 pCi/L 201 198 101 Pass Cr-51 pCi/L 208 259 80 Pass Cs-134 pCi/L 150 148 101 Pass Cs-137 pCi/L 109 105 104 Pass Fe-59 pCi/L 116 102 114 Pass Mn-54 pCi/L 129 135 95 Pass Zn-65 pCi/L 218 227 96 Pass E13064 Water I-131 pCi/L 67.4 80.5 84 Pass Detector 4 Ce-141 pCi/L 126 117 107 Pass Co-58 pCi/L 100 102 98 Pass Co-60 pCi/L 204 198 103 Pass Cr-51 pCi/L 216 259 83 Pass Cs-134 pCi/L 150 148 102 Pass Cs-137 pCi/L 106 105 101 Pass Fe-59 pCi/L 119 102 116 Pass Mn-54 pCi/L 159 135 117 Pass Zn-65 pCi/L 211 227 93 Pass (a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) Analytics evaluation based on EIS internal QC limits in accordance with the NRC Resolution Test criteria (Page 2 of 3)

TABLE E.4 Analytics Environmental Radioactivity Cross Check Program Exelon Industrial Services (2020)

EIS Identification Known Ratio of Analytics Month/Year Matrix Nuclide Units Reported Evaluation (b)

Number Value (a) to EIS Result Value E13064 Water I-131 pCi/L 90.2 80.5 112 Pass Ce-141 pCi/L 119 117 102 Pass Co-58 pCi/L 110 102 108 Pass Co-60 pCi/L 188 198 95 Pass Cr-51 pCi/L 229 259 89 Pass Cs-134 pCi/L 141 148 95 Pass Cs-137 pCi/L 105 105 100 Pass Fe-59 pCi/L 106 102 104 Pass Mn-54 pCi/L 150 135 111 Pass Zn-65 pCi/L 221 227 97 Pass September 2020 E13066 AP Gr-B pCi 174 162 107 Pass Gr-B pCi 175 162 108 Pass December 2020 E13067 AP Ce-141 pCi/Filter 77.1 78.4 98.3 Pass Detector 2 Co-58 pCi/Filter 64.3 66.1 97.2 Pass Co-60 pCi/Filter 117 119 98.3 Pass Cr-51 pCi/Filter 184 199 92.3 Pass Cs-134 pCi/Filter 79.3 84.5 93.8 Pass Cs-137 pCi/Filter 92.3 99.9 92.4 Pass Fe-59 pCi/Filter 101 87.9 115 Pass Mn-54 pCi/Filter 109 112 97.5 Pass Zn-65 pCi/Filter 105 149 70.6 Fail(1)

December 2020 E13067 AP Ce-141 pCi/Filter 83.9 78.4 107 Pass Detector 5 Co-58 pCi/Filter 63.0 66.1 95.3 Pass Co-60 pCi/Filter 124 119 104 Pass Cr-51 pCi/Filter 197 199 98.9 Pass Cs-134 pCi/Filter 72.2 85 85.5 Pass Cs-137 pCi/Filter 95.0 99.9 95.1 Pass Fe-59 pCi/Filter 111 87.9 126 Pass Mn-54 pCi/Filter 125 112 112 Pass Zn-65 pCi/Filter 111 149 74.7 Fail(1)

December 2020 E13068 Water Gr-B pCi/L 300 277 108 Pass E13070 Cartridge I-131 pCi 73.4 78.3 93.7 Pass Detector 2, 5 pCi 79.4 78.3 101 Pass E13070 Milk I-131 pCi/L 83.3 91.9 90.6 Pass Ce-141 pCi/L 106 100 106 Pass Co-58 pCi/L 72.7 84.3 86.3 Pass Co-60 pCi/L 150 152 98.8 Pass Cr-51 pCi/L 231 253 91.4 Pass Cs-134 pCi/L 89.6 108 83.0 Pass Cs-137 pCi/L 120 127 94.6 Pass Fe-59 pCi/L 116 112 103 Pass Mn-54 pCi/L 146 143 102 Pass Zn-65 pCi/L 135 190 71.2 Fail(1)

(a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) Analytics evaluation based on EIS internal QC limits in accordance with the NRC Resolution Test criteria (1) Failures caused by clerical error in calculation spreadsheet (Page 3 of 3)

TABLE E.5 ERA Environmental Radioactivity Cross Check Program Exelon Industrial Services (2020)

EIS Acceptance Known Month/Year ID Number Matrix Nuclide Units Reported Ratio of ERA Evaluation (b)

Value (a)

Value to EIS Result April 2020 RAD-121 Water Ba-133 pCi/L 40.1 41.8 96 Pass Cs-134 pCi/L 46.5 46.3 100 Pass Cs-137 pCi/L 225 234 96 Pass Co-60 pCi/L 50.7 50.3 101 Pass Zn-65 pCi/L 87.8 86.8 101 Pass I-131 pCi/L 29.7 28.9 103 Pass GR-B pCi/L 43.3 60.5 72 Fail(2)

September 2020 MRAD-33 AP Am-241 pCi/Filter 26.1 22.2 118 Pass Cs-134 pCi/Filter 270 296 91 Pass Cs-137 pCi/Filter 439 413 106 Pass Co-60 pCi/Filter 528 497 106 Pass Zn-65 pCi/Filter 528 500 106 Pass October 2020 RAD-123 Water Ba-133 pCi/L 33.3 37.0 90 Pass Detector 2 Cs-134 pCi/L 53.7 52.7 102 Pass Cs-137 pCi/L 136 131 104 Pass Co-60 pCi/L 68.8 60.6 114 Pass Zn-65 pCi/L 150 162 93 Pass I-131 pCi/L 27.5 28.2 97 Pass (a) The ERA known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation.

(b) ERA evaluation based on EIS internal QC limits in accordance with the NRC Resolution Test criteria (2) Passed vendor acceptance criteria, but failed NRC Resolution Test criteria (Page 1 of 1)

Intentionally left blank APPENDIX E ERRATA DATA

Intentionally left blank There was no errata data for 2020.

E-1

Intentionally left blank APPENDIX G ANNUAL RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM REPORT (ARGPPR)

Intentionally Left Blank Docket No: 50-352 50-353 LIMERICK GENERATING STATION UNITS 1 AND 2 Annual Radiological Groundwater Protection Program Report 1 January through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services Limerick Power Station Pottstown, PA 19464 April 2021

Intentionally Left Blank Table of Contents I. Summary and Conclusions .............................................................................................. 1 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 III. Program Description....................................................................................................... 5 A. Sample Analysis .................................................................................................. 5 B. Data Interpretation ............................................................................................... 5 C. Background Analysis ......................................................................................... 6

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

Appendices Appendix A Location Designation Tables Table A-1 Radiological Groundwater Protection Program - Sampling Locations for the Limerick Generating Station, 2020 Figures Figure 1 Routine Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Figure 2 Routine Precipitation Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Appendix B Data Tables Tables Table B-I.1 Concentrations of Tritium, Strontium, Gross Alpha and Gross Beta in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Table B-I.2 Concentrations of Gamma Emitters in Well Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Table B-I.3 Concentrations of Hard To Detects in Groundwater Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Table B-II.1 Concentrations of Tritium in Precipitation Water Samples Collected as Part of the Radiological Groundwater Protection Program, Limerick Generating Station, 2020

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 2020 through 31 December 2020. During that time period, 117 analyses were performed on 53 samples from 13 groundwater and 12 precipitation water locations collected from the environment, both on and off station property in 2020.

Groundwater samples were analyzed for tritium. Low levels of tritium were detected at 2 of the 13 groundwater monitoring locations. All other results were less than the required Exelon-specified LLD of 200 pCi/L.

Groundwater samples were analyzed for strontium-89 (Sr-89) and strontium-90 (Sr-90). All Sr-89 and Sr-90 results were less than the MDC.

Groundwater was analyzed for gross alpha in dissolved and suspended fractions.

Gross alpha (dissolved) was detected at 3 of the 13 groundwater locations sampled. Gross alpha (suspended) was detected at 2 of the 13 groundwater locations sampled.

Groundwater was analyzed for gamma-emitting radionuclides associated with the renewed licensed plant operation. Naturally-occurring potassium-40 (K-40) was detected in 1 of 13 groundwater locations. All other gamma isotopic results were less than the MDC.

Hard-To-Detect (HTD) analyses are routinely performed on a once per five year frequency for all groundwater monitoring locations. No HTD analyses were performed in 2020.

Precipitation water samples were analyzed for tritium. Tritium was detected at 6 of 12 precipitation locations sampled.

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. Additionally, there does not appear to be an active source of tritium to groundwater at the Station.

1

II. Introduction The Limerick Generating Station (LGS), consisting of two 3515 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 riverbank elevation rises from approximately 110 to 300 feet mean sea level (MSL). On the western riverbank elevation rises to approximately 50 feet MSL.

This report covers those analyses performed by Teledyne Brown Engineering (TBE) on samples collected in 2020.

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.

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 2006 Phase 1 study. The Phase 1 study results and conclusions were made available to state and federal regulators in station specific reports.

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 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 by Exelon Industrial Services (EIS). This section describes the general collection methods used to obtain environmental samples for the LGS RGPP in 2020. Sample locations can be found in Table A-1, Appendix A.

1. Sample Collection Groundwater Samples of groundwater were collected, managed, transported and analyzed in accordance with approved procedures following EPA methods. 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. Both station personnel and an independent hydrogeologist reviewed analytical data results for adverse trends or changes to hydrogeological conditions.

Precipitation A five-gallon precipitation collection bucket fitted with a funnel was installed at four locations around the Limerick Generating Station.

Three collection buckets were located on site in the highest prevalent wind sectors and one located on site in the least prevalent wind sector.

3

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.

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III. Program Description A. Sample Analysis This section lists the analyses performed by TBE and GEL Laboratories, LLC (GEL) on environmental samples for the LGS RGPP in 2020. The analytical procedures used by the laboratories are listed in the AREOR Appendix B Table B-3.

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

1. Concentrations of tritium in groundwater and precipitation water

2. Concentrations of gross alpha (dissolved and suspended) in groundwater

3. Concentrations of gamma-emitters (Be-7, K-40, 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) in groundwater

4. Concentrations of strontium (Sr-89 and Sr-90) in groundwater 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.

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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 (+/-) 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 is 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.

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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 Sr-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 USEPAs RadNet database. GNIP provides tritium precipitation concentration data for samples collected worldwide since 1960. RadNet provides tritium precipitation concentration data for samples collected at stations throughout 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 have typically been below 100 pCi/L since approximately 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 radioanalytical 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.

The surface water data ends in 1999 as the USEPA RadNet surface water program was terminated in March 1999.

The Exelon fleet-wide and Limerick RGPP was modified at the beginning of 2020. Changes to the RGPP included sample locations, frequency and the removal of surface water sampling.

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IV. Results and Discussion 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:

Tritium Samples from 13 locations were analyzed for tritium activity. (Appendix B, Table B-I.1) Tritium values ranged from non-detectable to 743 pCi/L.

Although no drinking water pathway is available from groundwater, the theoretical dose via the drinking water pathway was calculated at 0.044 mrem to a child (total body), which represents 0.73% of the 10 CFR 50, Appendix I dose limit of 6 mrem.

Strontium Samples were analyzed for Sr-89 and Sr-90. All results were below the required LLDs. (Appendix B, Table B-I.1)

Gross Alpha (dissolved and suspended)

All samples were analyzed for gross alpha in the dissolved and suspended fractions once in July 2020. An additional sample was taken in October at one location. Gross alpha (dissolved) was detected in 3 of the 13 groundwater locations. The concentrations ranged from 1.6 to 3.4 pCi/L.

Gross alpha (suspended) was detected in 2 of 13 groundwater locations sampled with concentrations ranging from 2.3 to 11.0 pCi/L.

(Appendix B, Table B-I.1)

Gamma Emitters Samples were analyzed for gamma-emitting nuclides. Naturally-occurring potassium-40 (K-40) was detected in 1 of the 13 locations sampled at a concentration of 40 pCi/L, All other gamma results were below the required LLDs. (Appendix B, Table B-I.2)

Hard-To-Detect No HTD analyses were performed in 2020. (Appendix B, Table B-I.3)

B. Precipitation Sample Results Tritium Tritium activity was detected in 6 of 12 precipitation water locations analyzed. The concentrations ranged from 193 to 464 pCi/L. These 9

concentrations are consistent with historical values observed.

(Appendix B, Table B-II.1)

C. Drinking Water Well Survey In April, 2019, GHD (formerly Conestoga Rover Associates) conducted a comprehensive database search (PaGWIS) for private and public wells within one mile of the Station. The detailed results of the 2019 well search are presented in Appendix C of the 2019 Hydrogeologic Investigation Report for Limerick Generating Station. In general, the well depths range from 45 to 585 feet bgs, and yield between 2 and 65 gpm. All wells are completed in the Brunswick Formation. In the GHD report, Figure 2.3 presents the approximate locations of the water wells that surround the Station.

A review of the PaGWIS database table reveals the following type and associated number of off-Station wells within the on-mile radius of the Station:

x Domestic = 41 wells (68%)

x Industrial = 5 wells (8%)

x Observation = 9 wells (15%)

x Abandoned = 5 wells (8%)

x Total = 60 wells One well was identified at the active quarry, which is approximately 2,000 feet to the northwest of the Station. The PaGWIS database search identifies the quarry well as constructed to a depth of 100 feet bgs, and reportedly yields at least 50,400 gpd (35 gpm). A well inventory included in the Stations USFAR cites the total depth of the quarry supply well as 130 feet bgs, with a yield of 100 gpm, and typical operation of 50 gpm for ten hours a day.

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 2014. The pump was placed at a depth of approximately 294 feet BGS. The total well depth and the depth of the steel casing are approximately 310 feet BGS. The well is located approximately 175 feet east of the Reactor Building. The potable supply well is sampled as part of the RGPP and designated as DW-LR-1. In 2019, DW-LR-1 pumped 6,785,500 gallons.

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 10

in an emergency fire situation and for system testing and flushing. In 2019, 1,709,275 gallons were pumped from the well.

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 There were no spills to ground containing radioactive material in 2020.

F. Trends Low level tritium detections in monitoring well MW-LR-5 are being trended.

G. Investigations Intermittent, low-level tritium detections in monitoring well MW-LR-5 are currently being investigated.

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 monitoring wells.

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

V. References

1. GHD, Inc. Hydrogeologic Investigation Report, Limerick Generating Station, 3146 Sanatoga Road, Pottstown, Pennsylvania, Ref. No. 11189800(1),

December 2019

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 11

Intentionally left blank APPENDIX A LOCATION DESIGNATION

Intentionally left blank TABLE A-1: Radiological Groundwater Protection Program - Sampling Locations for the Limerick Generating Station, 2020 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 MW-LR-10 Monitoring Well Onsite P3 Monitoring Well Onsite P11 Monitoring Well Onsite P14 Monitoring Well Onsite P17 Monitoring Well Onsite DW-LR-1 Monitoring Well Onsite 36S3 Precipitation Water Onsite E-5 Precipitation Water Onsite ESE-6 Precipitation Water Onsite RS-1 Precipitation Water Onsite RS-2 Precipitation Water Onsite RS-3 Precipitation Water Onsite RS-4 Precipitation Water Onsite RS-5 Precipitation Water Onsite RS-6 Precipitation Water Onsite RS-7 Precipitation Water Onsite RS-8 Precipitation Water Onsite SE-7 Precipitation Water Onsite A-1

Figure 1 Routine Well Water and Surface Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Figure 2 Routine Precipitation Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 Figure 1 Routine Well Water Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 A-2

Figure 2 Routine Precipitation Sample Locations for the Radiological Groundwater Protection Program, Limerick Generating Station, 2020 A-3

Intentionally left blank APPENDIX B DATA TABLES

Intentionally left blank TABLE B-I.1 CONCENTRATIONS OF TRITIUM, STRONTIUM, AND GROSS ALPHA IN WELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 Sr-89 Sr-90 Gr-A (Dis) Gr-A (Sus)

DW-LR-1 01/28/20 < 186 DW-LR-1 07/22/20 < 160 < 7.0 < 0.8 1.6 +/- 0.7 < 0.6 DW-LR-1 10/28/20 < 183 MW-LR-1 07/21/20 < 161 MW-LR-2 07/21/20 < 163 MW-LR-3 07/21/20 < 165 MW-LR-4 01/28/20 < 182 MW-LR-4 07/21/20 < 164 < 8.5 < 0.8 < 1.2 < 0.6 MW-LR-4 10/27/20 < 180 MW-LR-5 07/21/20 < 163 MW-LR-7 07/21/20 < 168 MW-LR-8 01/28/20 519 +/- 137 MW-LR-8 07/22/20 417 +/- 118 < 5.8 < 1.0 < 1.1 2.6 +/- 1.1 MW-LR-8 07/22/20 DUP 536 +/- 122 < 7.8 < 0.8 < 1.1 2.3 +/- 1.1 MW-LR-8 07/22/20 GEL 451 +/- 190 < 2.7 < 0.9 (1) 9.7 +/- 2.3 MW-LR-8 10/28/20 518 +/- 135 MW-LR-8 10/28/20 DUP 375 +/- 128 MW-LR-8 10/28/20 GEL 456 +/- 96 MW-LR-9 01/28/20 743 +/- 153 MW-LR-9 01/28/20 DUP 742 +/- 152 MW-LR-9 01/28/20 GEL 835 +/- 162 MW-LR-9 07/22/20 648 +/- 133 < 2.6 < 0.9 < 0.8 7.6 +/- 2.6 MW-LR-9 07/22/20 DUP 672 +/- 135 < 3.5 < 0.8 < 1.0 6.3 +/- 2.7 MW-LR-9 07/22/20 GEL 698 +/- 205 < 8.5 < 0.4 (1) 5.2 +/- 3.3 MW-LR-9 10/28/20 623 +/- 143 2.6 +/- 1.3 11.0 +/- 5.3 MW-LR-9 10/28/20 DUP 674 +/- 142 < 2.0 9.3 +/- 4.4 MW-LR-9 10/28/20 GEL 542 +/- 102 (1) 123 +/- 15.9 MW-LR-10 01/28/20 < 186 MW-LR-10 07/22/20 < 161 < 8.3 < 0.7 3.4 +/- 1.0 < 0.6 MW-LR-10 10/28/20 < 185 P11 01/28/20 < 188 P11 07/22/20 < 160 < 6.4 < 0.7 < 1.1 < 0.6 P11 10/28/20 < 187 P14 01/28/20 < 184 P14 07/22/20 < 162 < 6.3 < 0.9 < 2.3 < 0.9 P14 10/28/20 < 185 P17 07/21/20 < 166 (1) Total gross alpha results reported (not dissolved/suspended)

B-1

TABLE B-I.2 CONCENTRATIONS OF GAMMA EMITTERS IN WELL WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE Be-7 K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 DW-LR-1 07/22/20 < 19 < 32 < 2 < 2 < 5 < 3 < 5 < 3 < 4 < 4 < 2 < 2 < 11 < 4 MW-LR-1 07/21/20 < 17 < 32 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 4 < 2 < 2 < 10 < 3 MW-LR-2 07/21/20 < 16 < 39 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 3 < 2 < 2 < 9 < 3 MW-LR-3 07/21/20 < 18 < 22 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 3 < 2 < 2 < 10 < 4 MW-LR-4 07/21/20 < 17 < 20 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 3 < 2 < 2 < 10 < 3 MW-LR-5 07/21/20 < 19 < 30 < 2 < 2 < 5 < 2 < 5 < 3 < 4 < 4 < 2 < 2 < 11 < 4 MW-LR-7 07/21/20 < 17 < 19 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 4 < 2 < 2 < 10 < 4 MW-LR-8 07/22/20 < 16 < 37 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 3 < 2 < 2 < 10 < 3 MW-LR-8 07/22/20 DUP < 18 < 33 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 4 < 2 < 2 < 11 < 4 MW-LR-8 07/22/20 GEL (1) (1) < 1 < 2 < 4 < 2 < 3 < 2 < 3 < 5 < 2 < 2 < 12 < 4 MW-LR-9 07/22/20 < 15 < 32 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 4 < 2 < 2 < 9 < 3 MW-LR-9 07/22/20 DUP < 19 < 19 < 2 < 2 < 4 < 2 < 5 < 2 < 4 < 4 < 3 < 2 < 11 < 3 MW-LR-9 07/22/20 GEL (1) (1) < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 5 < 2 < 2 < 12 < 4 B-2 MW-LR-10 07/22/20 < 21 < 28 < 2 < 2 < 5 < 2 < 5 < 3 < 4 < 5 < 2 < 2 < 13 < 4 P11 07/22/20 < 21 < 21 < 2 < 2 < 5 < 2 < 4 < 3 < 4 < 4 < 3 < 2 < 12 < 4 P14 07/22/20 < 14 < 28 < 1 < 2 < 3 < 2 < 3 < 2 < 3 < 3 < 2 < 2 < 9 < 3 P17 07/21/20 < 15 40 +/- 25 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 3 < 2 < 2 < 8 < 3 (1) No result reported

TABLE B-I.3 CONCENTRATIONS OF HARD TO DETECTS IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD AM-241 CM-242 CM-243/244 PU-238 PU-239 U-233/234 U-235 U-238 FE-55 NI-63 There were no HTD's Analyzed in 2020 B-3

TABLE B-II.1 CONCENTRATIONS OF TRITIUM IN PRECIPITATION WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, LIMERICK GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 36S3 05/04/20 - 05/19/20 < 173 36S3 10/28/20 - 11/17/20 < 191 E-5 05/04/20 - 05/19/20 < 176 E-5 10/28/20 - 11/17/20 < 188 ESE-6 05/04/20 - 05/19/20 < 178 ESE-6 10/28/20 - 11/17/20 < 192 RS-1 10/28/20 - 11/17/20 210 +/- 127 RS-2 10/28/20 - 11/17/20 < 189 RS-3 10/27/20 - 11/17/20 < 192 RS-4 10/28/20 - 11/17/20 193 +/- 126 RS-5 10/28/20 - 11/17/20 204 +/- 124 RS-6 10/28/20 - 11/17/20 238 +/- 119 RS-7 10/28/20 - 11/17/20 < 187 RS-8 10/28/20 - 11/17/20 464 +/- 137 SE-7 05/04/20 - 05/19/20 218 +/- 115 SE-7 10/28/20 - 11/17/20 < 190 B-4

LG-20-045, Annual Radiological Operating Report

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