TMI-21-019, Submittal of 2020 Annual Radiological Environmental Operating Report

Submittal of 2020 Annual Radiological Environmental Operating Report

ML21120A011
Person / Time
Site:	Three Mile Island
Issue date:	04/27/2021
From:	Orth T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TMI-21-019
Download: ML21120A011 (161)

Text

Three Mile Island Nuclear Station, Unit 1 Exelon Generation 441 S. P.O. Box 480 Middletown, PA 17057 TMI-21-019 April 27, 2021 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Renewed Facility License No. DPR-50 NRC Docket Nos. 50-289 Three Mile Island Nuclear Station, Unit 2 Possession Only License No. DPR-73 NRC Docket No. 50-320

Subject:

2020 Annual Radiological Environmental Operating Report In accordance with TMI-1 Technical Specification 6.9.2.1 and TMI-2 Technical Specification 6.8.1.1, enclosed is the Annual Radiological Environmental Operating Report covering the time period for January 1 through December 31, 2019, for the Three Mile Island Nuclear Station.

There are no commitments in this letter.

Should you have any questions concerning this letter, please contact Mr. Daniel Jordan, Chemistry/Environmental Specialist, at (717) 948-8470.

Respectfully, Trevor L. Orth Site Decommissioning Director Three Mile Island Nuclear Station, Unit 1

Attachment:

Three Mile Island 2020 Annual Radiological Environmental Operating Report cc: w/ Attachment Regional Administrator - NRC Region I NRC Project Manager, NMSS - Three Mile Island, Unit 1 and Unit 2 W. DeHaas - Commonwealth of Pennsylvania - Bureau of Radiation Protection G. Van Noordennen - TMI-2 Solutions, LLC

Docket No: 50-289 50-320 THREE MILE ISLAND NUCLEAR STATION UNITS 1 AND 2 Annual Radiological Environmental Operating Report 1 January through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services Exelon Generation Three Mile Island Nuclear Station Middletown, PA 17057 April 2021

Intentionally left blank Table Of Contents I. Summary and Conclusions .............................................................................................. 1 II. Introduction ..................................................................................................................... 3 A. Objectives of the REMP ...................................................................................... 3 B. Implementation of the Objectives ........................................................................ 3 III. Program Description ...................................................................................................... 4 A. Sample Collection................................................................................................ 4 B. Sample Analysis .................................................................................................. 6 C. Data Interpretation............................................................................................... 6 D. Program Exceptions ............................................................................................ 7 E. Program Changes ............................................................................................... 8 IV. Results and Discussion ................................................................................................. 9 A. Aquatic Environment ........................................................................................... 9

1. Surface Water ........................................................................................... 9

2. Drinking Water .......................................................................................... 9

3. Effluent Water ......................................................................................... 10

4. Storm Water............................................................................................ 11

5. Ground Water ......................................................................................... 11

6. Fish ......................................................................................................... 11

7. Sediment................................................................................................. 12 B. Atmospheric Environment ................................................................................. 12

1. Airborne Particulates .............................................................................. 12

a. Air Particulates............................................................................. 12

b. Airborne Iodine ............................................................................ 13

2. Terrestrial ................................................................................................ 13

a. Milk .............................................................................................. 13

b. Food Products ............................................................................. 13 C. Ambient Gamma Radiation ............................................................................... 14 D. Land Use Survey............................................................................................... 14 E. Radiological Impact of TMINS Operations ........................................................ 15 F. Errata Data ........................................................................................................ 21 G. Summary of Results - Inter-laboratory Comparison Program .......................... 21 V. References ................................................................................................................... 25 i

Appendices Appendix A Radiological Environmental Monitoring Report Summary Tables Table A-1 Radiological Environmental Monitoring Program Annual Summary for the Three Mile Island Nuclear Station, 2020 Appendix B Location Designation, Distance & Direction And Sample Collection &

Analytical Methods Tables Table B-1 Location Designation and Identification System for the Three Mile Island Nuclear Station Table B-2 Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Three Mile Island Nuclear Station, 2020 Table B-3 Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Three Mile Island Nuclear Station, 2020 Figures Figure B-1 Environmental Sampling Locations Within One Mile of the Three Mile Island Nuclear Station, 2020 Figure B-2 Environmental Sampling Locations Between One and Five Miles from the Three Mile Island Nuclear Station, 2020 Figure B-3 Environmental Sampling Locations Greater Than Five Miles from the Three Mile Island Nuclear 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 Three Mile Island Nuclear Station, 2020 Table C-I.2 Concentrations of I-131 in Surface Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-I.3 Concentrations of Gamma-Emitters in Surface Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 ii

Table C-II.1 Concentrations of Gross Beta in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-II.2 Concentrations of I-131 in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-II.3 Concentrations of Tritium in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-II.4 Concentrations of Gamma-Emitters in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-III.1 Concentrations of Gross Beta, I-131, Tritium, and Strontium in Effluent Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-III.2 Concentrations of Gamma-Emitters in Effluent Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-IV.1 Concentrations of Strontium in Predator and Bottom Feeder (Fish)

Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-IV.2 Concentrations of Gamma-Emitters in Predator and Bottom Feeder (Fish) Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-V.1 Concentrations of Gamma-Emitters in Sediment Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VI.1 Concentrations of Gross Beta in Air Particulate Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VI.2 Monthly and Yearly Mean Values of Gross Beta Concentrations (E-3 pCi/cu meter) in Air Particulate Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VI.3 Concentrations of Gamma-Emitters in Air Particulate Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VII.1 Concentrations of I-131 in Air Iodine Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VIII.1 Concentrations of I-131 in Milk Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VIII.2 Concentrations of Strontium in Milk Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-VIII.3 Concentrations of Gamma-Emitters in Milk Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table C-IX.1 Concentrations of Strontium and Gamma-Emitters in Food Product Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 iii

Table C-X.1 Quarterly OSLD Results for Three Mile Island Nuclear Station, 2020 Table C-X.2 Mean Quarterly OSLD Results for the Site Boundary, Indicator and Control Locations for Three Mile Island Nuclear Station, 2020 Table C-X.3 Summary of the Ambient Dosimetry Program for Three Mile Island Nuclear Station, 2020 Figures Figure C-1 Monthly Tritium Concentrations in Surface Water and Effluent Water Three Mile Island Nuclear Station, 2020 Figure C-2 Mean Quarterly Tritium Concentrations in Surface Water Three Mile Island Nuclear Station, 1974 - 2020 Figure C-3 Mean Monthly Gross Beta Concentrations in Drinking Water Three Mile Island Nuclear Station, 2020 Figure C-4 Mean Monthly Tritium Concentrations in Drinking Water and Effluent Water Three Mile Island Nuclear Station, 2020 Figure C-5 Mean Cesium-137 Concentrations in Aquatic Sediments Three Mile Island Nuclear Station, 1984 - 2020 Figure C-6 Mean Quarterly Gross Beta Concentrations in Air Particulates Three Mile Island Nuclear Station, 1972 - 2020 Figure C-7 Mean Weekly Gross Beta Concentrations in Air Particulates Three Mile Island Nuclear Station, 2007 - 2020 Figure C-8 Mean Quarterly Strontium-90 Concentrations in Cow Milk Three Mile Island Nuclear Station, 1979 - 2020 Appendix D Data Tables and Figures - Comparison Laboratory Tables Table D-I.1 Concentrations of Gross Beta in Drinking Water Samples Collected in the Vicinity Of Three Mile Island Nuclear Station, 2020 Table D-I.2 Concentration of Tritium in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-I.3 Concentrations of Iodine-131 in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-I.4 Concentrations of Gamma-Emitters in Drinking Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-II.1 Concentrations of Strontium and Gamma-Emitters in Fish Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-III.1 Concentrations of Gamma-Emitters in Sediment Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 iv

Table D-IV.1 Concentrations of Gamma-Emitters and Strontium in Food Product Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-V.1 Concentrations of Gross Beta in Air Particulate and I-131 in Air Iodine Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-V.2 Concentrations of Gamma-Emitters in Air Particulate Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table D-VI.1 Concentrations of I-131 by Chemical Separation, Gamma-Emitters, and Strontium in Milk Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Figures Figure D-1 Monthly Gross Beta Concentrations in Drinking Water Samples Collected From TMINS Location Q9-1Q, 2020 Figure D-2 Weekly Gross Beta Concentrations in Air Particulate Samples Collected from TMINS Location E1-2Q, 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, Inc., 2020 Table E-7 ERA Environmental Radioactivity Cross Check Program GEL Laboratories, Inc., 2020 Table E-8 Analytics Environmental Radioactivity Cross Check Program GEL Laboratories, Inc., 2020 Appendix F Annual Radiological Groundwater Protection Program Report (ARGPPR) v

Intentionally Left Blank I. Summary and Conclusions This report on the Radiological Environmental Monitoring Program conducted for the Three Mile Island Nuclear Station (TMINS) by Exelon covers the period 1 January 2020 through 31 December 2020. During that time period, 1,650 analyses were performed on 1,304 samples. In assessing all the data gathered for this report and comparing these results with preoperational data and operational REMP data, it was concluded that the operation of TMINS had no adverse radiological impact on the environment.

Surface, drinking and effluent water samples were analyzed for concentrations of tritium and gamma-emitting nuclides. Surface, drinking and effluent water samples were also analyzed for concentrations of iodine-131 (I-131). Drinking and effluent water samples were also analyzed for concentrations of gross beta.

Effluent water samples were analyzed for concentrations of strontium-89 (Sr-89) and strontium-90 (Sr-90). All groundwater, precipitation water, and stormwater results are reported in the ARGPPR, Appendix F. No I-131, Sr-89 or Sr-90 activities were detected. Gross beta concentrations detected were consistent with those detected in previous years. Tritium activity in 5 surface water samples and 8 monthly effluent water samples was due to TMINS activities or releases.

No other fission or activation products potentially attributed to TMI liquid releases were detected.

Fish (predator and bottom feeder) and sediment samples were analyzed for concentrations of gamma-emitting nuclides. Fish samples were also analyzed for concentrations of Sr-90. No Sr-90 activity was detected. No fission or activation products were detected in fish or in sediment samples.

Air particulate samples were analyzed for concentrations of gross beta and gamma-emitting nuclides. Gross beta activity is consistent with data from previous years. Cosmogenic beryllium-7 (Be-7) was detected at levels consistent with those detected in previous years. No other activation products were detected.

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

Cow milk samples were analyzed for concentrations of I-131, gamma-emitting nuclides, Sr-89, and Sr-90. Concentrations of naturally-occurring potassium-40 (K-40) were consistent with those detected in previous years. No I-131, Sr-89 or Sr-90 activities were detected. Occasionally Sr-90 activity may be detected.

These results have been is consistent with results in previous years and were attributed to fallout from nuclear weapons testing. No other fission or activation products were found.

Food Product samples were analyzed for concentrations of gamma-emitting nuclides including I-131 and Sr-90. Concentrations of naturally-occurring Be-7 and K-40 were consistent with those detected in previous years. No other fission or activation products were detected.

Beginning in 2012, Exelon changed the type of dosimetry used for the Radiological Environmental Monitoring Program (REMP). Optically Stimulated Luminescent Dosimetry (OSLD) were deployed and Thermo-luminescent Dosimetry (TLD) were discontinued. This change resulted in a slight change in process and reporting of quarterly results. The relative comparison to control locations remains valid. OSLD technology is different than that used in a TLD but has the same purpose (to measure direct radiation).

In conclusion, radioactive materials related to TMINS operations were detected in environmental samples, but the measured concentrations were low and consistent with measured effluents. The environmental sample results verified that the doses received by the public from TMINS effluents in 2020 were well below applicable dose limits and only a small fraction of the doses received from natural background radiation. Additionally, the results indicated that there was no permanent buildup of radioactive materials in the environment and no increase in background radiation levels.

Therefore, based on the results of the radiological environmental monitoring program (REMP) and the doses calculated from measured effluents, TMINS operations in 2020 did not have any adverse effects on the health of the public or on the environment.

II. Introduction The Three Mile Island Nuclear Station (TMINS), consisting of two pressurized water reactors (PWR), is located on the northern end of Three Mile Island in the Susquehanna River approximately 2.5 miles south of Middletown in Londonderry Township, Dauphin County, Pennsylvania. TMI-1 is owned and operated by Exelon and became operational in 1974. TMI-2 is operated by GPU Nuclear, Inc.

and owned by Metropolitan Edison (50%), Pennsylvania Electric (25%) and Jersey Central Power & Light (25%). TMI-2 became operational in 1978 and was shut down following the 1979 accident. At the end of 1993 TMI-2 was placed in a condition called Post-Defueling Monitored Storage. TMI-2 is maintained by Exelon under contract with GPU Nuclear.

A Radiological Environmental Monitoring Program (REMP) for TMINS was initiated in 1974. This report covers those analyses performed by Teledyne Brown Engineering (TBE), Landauer and Exelon Industrial Services (EIS)/GEL Laboratories on samples collected during the period 1 January 2020 through 31 December 2020.

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

1. Evaluate the relationship between quantities of radioactive material released from the plant and resultant radiation doses to individuals from principal pathways of exposure.

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

3. To verify in-plant controls for the containment of radioactive materials.

4. To determine buildup of long-lived radionuclides in the environment and changes in background radiation levels.

5. To provide reassurance to the public that the program is capable of adequately assessing impacts and identifying noteworthy changes in the radiological status of the environment.

6. To fulfill the requirements of the TMI-1 and TMI-2 Technical Specifications.

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.

Intentionally left blank III. Program Description A. Sample Collection Samples for the TMINS REMP were collected for Exelon by Exelon Industrial Services, LLC (EIS) and Normandeau Associates, Inc. (NAI).

This section describes the general collection methods used by EIS & NAI to obtain environmental samples for the TMINS 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 & NAI are listed in Table B-3.

Aquatic Environment The aquatic environment was evaluated by performing radiological analyses on samples of surface water, drinking water, effluent water, fish and sediment. Two gallon water samples were collected monthly from continuous samplers located at two surface water locations (J1-2 and Q9-1), three drinking water locations (G15-2, G15-3 and Q9-1), and one effluent water location (K1-1). A composite of weekly grab samples at one surface water location (A3-2) were collected. The control locations were A3-2 and Q9-1. All groundwater and storm water results are reported in the ARGPPR, Appendix F.

All water samples were collected in unused plastic bottles, which were rinsed at least twice with source water prior to collection. Fish samples comprising the flesh of two groups, bottom feeders and predators, were collected semiannually at an upstream control (BKG) and a downstream indicator (IND) location. Location IND could be affected by TMINS effluent releases. Sediment samples composed of recently deposited substrate were collected semiannually at three locations (A1-3, J2-1 and K1-3).

Location A1-3 was the control.

Atmospheric Environment The atmospheric environment was evaluated by performing radiological analyses on samples of air particulates and airborne iodine. Airborne iodine and particulate samples were collected and analyzed weekly at seven locations (A3-1, E1-2, F1-3, G2-1, H3-1, M2-1 and Q15-1). The control location was Q15-1. 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 The terrestrial environment was evaluated by performing radiological analyses on samples of milk and food product. Milk samples were collected biweekly at four locations (F4-1, G2-1, K15-3 and P4-1) from March through November, and monthly from December through February.

The control location was K15-3. 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.

Food products were collected from June through September at three locations (B10-2, E1-2 and H1-2), in lieu of milk sampling and annually from the four food product groups at two locations (B10-2 and H1-2). B10-2 was the control location for both annual and monthly sampling. Three different kinds of vegetation samples and twelve different kinds of vegetation leaves were collected, placed in new unused plastic bags, and sent to the laboratory for analysis.

Ambient Gamma Radiation Beginning in 2012, Exelon changed the type of dosimetry used for the Radiological Environmental Monitoring Program (REMP). Optically Stimulated Luminescent Dosimetry (OSLD) were deployed and Thermo-luminescent Dosimetry (TLD) were discontinued. This change may result in a step change in readings, up or down, depending on site characteristics.

The relative comparison to control locations remains valid. OSLD technology is different than that used in a TLD but has the same purpose (to measure direct radiation). The OSLDs were placed at locations on and around the TMINS site as follows:

A site boundary ring consisting of 19 locations (A1-4, B1-2, C1-2, D1-1, E1-4, F1-2, F1-4, G1-3, G1-5, G1-6, H1-1, J1-3, K1-4, L1-1, M1-1, N1-3, P1-2, Q1-2 and R1-1) 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 TMINS release.

An indicator ring consisting of 60 locations (A3-1, A5-1, A9-3, B1-1, B2-1, B5-1, B10-1, C1-1, C2-1, C5-1, C8-1, D1-2, D2-2, D6-1, E1-2, E2-3, E5-1, E7-1, F1-1, F2-1, F5-1, F10-1, G1-2, G2-4, G5-1, H3-1, H5-1, H8-1, J1-1, J3-1, J5-1, J7-1 K2-1, K3-1, K5-1, K8-1, L1-2, L2-1, L5-1, L8-1, M1-2, M2-1, M5-1, M9-1, N1-1, N2-1, N5-1, N8-1, P1-1, P2-1, P5-1, P8-1, Q1-1, Q2-1, Q5-1, Q9-1, R1-2, R3-1, R5-1 and R9-1) extending to approximately 10 miles from the site, designed to measure possible exposures to close-in population.

The balance of 11 locations (D15-1, F25-1, G10-1, G15-1, H15-1, J15-1, K15-1, L15-1, N15-2, Q15-1 and R15-1) represent control areas.

The specific dosimeter 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 221/2 degree sectors around the site, where estimated annual dose from TMINS, 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 Each station has two Al2O3:C Optically Stimulated Luminescence Dosimeters enclosed in plastic placed at each location in a frame located approximately 3-6 feet above ground level. Since each OSLD responds to radiation independently, this provides two independent detectors at each station.

B. Sample Analysis This section describes the general analytical methods used by TBE and EIS to analyze the environmental samples for radioactivity for the TMINS REMP in 2020. The analytical procedures used by the laboratories are listed in Table B-3.

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

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

2. Concentrations of gamma-emitters in surface, drinking, and effluent water, air particulates, milk, fish, sediment and food products

3. Concentrations of tritium in surface, drinking and effluent water

4. Concentrations of I-131 in surface, drinking and effluent water, air, milk and food products

5. Concentrations of strontium in effluent water, fish, milk and food products

6. Ambient gamma radiation levels at various site environs C. Data Interpretation Data were compared to previous years' operational data for consistency and trending. In addition, comparison to pre-operational data is sometimes made. For the purpose of this report, TMINS 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) was 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 was 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 were designed to achieve the required TMINS detection capabilities for environmental sample analysis.

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

2. 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 results for each type of sample were grouped as follows:

For surface, drinking, and effluent water 11 nuclides, Mn-54, Co-58, Fe-59, Co-60, Zn-65, Nb-95, Zr-95, Cs-134, Cs-137, Ba-140 and La-140 MDCs were reported.

For fish eight nuclides, K-40, Mn-54, Co-58, Fe-59, Co-60, Zn-65, Cs-134 and Cs-137 MDCs were reported.

For sediment six nuclides, K-40, Mn-54, Co-58, Co-60, Cs-134 and Cs-137 MDCs were reported.

For air particulate eight nuclides, Be-7, Mn-54, Co-58, Co-60, Nb-95, Zn-95, Cs-134 and Cs-137 MDCs were reported.

For milk five nuclides, K-40, Cs-134, Cs-137, Ba-140 and La-140 MDCs were reported.

For food products five nuclides, Be-7, K-40, I-131, Cs-134 and Cs-137 MDCs were reported.

Means and standard deviations of the 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 TMINS REMP had a sample recovery rate of 100%. Issue Reports (IR) were initiated to document significant exceptions and missing samples. All exceptions are listed below:

Water

1. G15-2 (Drinking Water)

For the sampling period 3/21/20 - 3/28/20, no water sample was collected. For the sampling period 03/28/20 - 04/04/20, a grab sample was collected due to no access to set up sampler the prior week.

(IR 04347697)

2. Q9-1 (Surface Water and Drinking Water)

For the sampling period 3/28/20 - 4/4/20, samplers were not set back up for collection due to no access to plant for visitors. No sample obtained. (IR 04347697)

3. Q9-1 (Surface Water and Drinking Water)

For the sampling periods 4/4/20 - 7/4/20, 7/4/20 - 10/3/20 and 10/3/20 - 1/2/21, composite samplers were not set back up for collection due to no access to plant for visitors. Weekly grab samples were collected by a plant worker at both locations and used to make a monthly composite. (IRs 04370872, 04390216 and 04405601)

Dosimetry

1. E1-2 For the sampling period 9/15/20 - 1/5/21, the field tech upon arrival found that the 3rd dosimeter was missing. The two main dosimeters of legal record were still inside the bracket, but the 3rd (QA) dosimeter

(#EX00041993L) was missing. The field tech did a complete sweep of the area, but nothing was found. Reference IR 04394059.

(IR 04405601)

Each program exception was reviewed to understand the causes of the program exception. Sampling and maintenance errors were reviewed with the personnel involved to prevent recurrence. Occasional equipment breakdowns and power outages 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 changes to the program in 2020.

Intentionally left blank IV. Results and Discussion A. Aquatic Environment

1. Surface Water Samples were taken weekly from a continuous sampler at two locations (J1-2 and Q9-1) and weekly grab samples from one location (A3-2). Weekly samples were composited on a monthly schedule. Of these locations only J1-2 located downstream could be affected by TMINS effluent releases. The following analyses were performed:

Tritium Monthly samples from J1-2 and Q9-1 were analyzed for tritium activity (Table C-I.1, Appendix C). Positive tritium activity was detected in 10 of 12 samples at location J1-2, which is located immediately downstream of the TMINS effluent outfall. The concentrations ranged from 426 to 2,910 pCi/L. The increased tritium concentrations detected were a result of TMINS releasing radwaste treatment system effluent water under permitted discharges in accordance with NRC regulations. The indicator surface water sample is taken just downstream of the liquid discharge outfall where mixing of liquid effluents with the river water is incomplete. More complete mixing is not achieved until liquid effluents pass over the York Haven Dam. This water is normally not consumed by humans. The concentrations detected were well below any regulatory limits.

(Figures C-1 and C-2, Appendix C)

Iodine Monthly samples were taken from location A3-2. This is a control or background station sampled because known medical discharges of radiopharmaceuticals occur into the surface water upstream of TMI from a nearby hospital. Monthly samples were taken from A3-2 and analyzed for I-131. (Table C-I.2, Appendix C). I-131 activity was not detected in any samples.

Gamma Spectrometry Locations J1-2 and Q9-1 were analyzed for gamma-emitting nuclides (Table C-I.3, Appendix C). All nuclides were less than the MDC.

2. Drinking Water Monthly samples were collected from continuous water samplers at three locations (G15-2, G15-3 and Q9-1). Two locations (G15-2 and G15-3) could be affected by TMINS effluent releases. The following analyses were performed:

Gross Beta Monthly samples from all locations were analyzed for concentrations of gross beta (Tables C-II.1, Appendix C). Gross beta activity was detected in 18 of 36 samples. The concentrations ranged from 1.9 to 5.3 pCi/L. Concentrations detected were consistent with those detected in previous years. (Figure C-3, Appendix C)

Iodine Monthly samples from all locations were analyzed for concentrations of I-131. I-131 activity was not detected in any sample.

(Table C-II.2, Appendix C)

Tritium Monthly samples from all locations were analyzed for tritium activity (Table C-II.3, Appendix C). Tritium was not detected in any sample.

(Figures C-4, Appendix C)

Gamma Spectrometry Samples from all locations were analyzed for gamma-emitting nuclides. All nuclides were less than the MDC.

(Table C-II.4, Appendix C)

3. Effluent Water Monthly samples were collected from a continuous water sampler at one location (K1-1). The following analyses were performed:

Gross Beta Monthly samples from location K1-1 were analyzed for concentrations of gross beta. Gross beta was detected in 7 of 12 samples. The concentrations ranged from 2.5 to 3.6 pCi/L. Concentrations detected were consistent with those detected in previous years.

(Tables C-III.1, Appendix C)

Iodine-131 Monthly samples from location K1-1 were analyzed for concentrations of I-131. I-131 was not detected in any of the samples.

(Tables C-III.1, Appendix C)

Tritium Monthly samples from location K1-1 were analyzed for tritium activity.

Tritium activity was detected in 10 of 12 samples. The concentrations ranged from 4,030 to 20,000 pCi/L. (Table C-III.1, Appendix C)

The elevated results were a result of TMI releasing radwaste treatment system effluent water under permitted discharges in accordance with NRC regulations. These results were from the liquid discharge mixing basin. The concentrations detected agree with those obtained from the TMINS Effluent Monitoring Program. (Figure C-4, Appendix C)

Strontium Semiannual composite samples from location K1-1 were analyzed for Sr-89 and Sr-90. No strontium activity was detected. The highest MDC was calculated at <4.7 pCi/L for Sr-89 and at <0.9 pCi/L for Sr-90. (Table C-III.1, Appendix C)

Gamma Spectrometry Samples from location K1-1 were analyzed for gamma-emitting nuclides. All nuclides were less than the MDC.

(Table C-III.2, Appendix C)

4. Storm Water Storm water results are included in the Annual Radiological Groundwater Protection Program (ARGPPR), Appendix F.

5. Ground Water Groundwater results are included in the Annual Radiological Groundwater Protection Program (ARGPPR), Appendix F.

6. Fish Fish samples comprised of bottom feeders and predators were collected at two locations (IND and BKG) semiannually. Location IND could be affected by TMINS effluent releases. The following analyses were performed:

Strontium The edible portions of fish samples from both locations were analyzed for Sr-90. No strontium activity was detected. The highest MDC was calculated at <4.7 pCi/kg wet for Sr-90. (Table C-IV.1, Appendix C)

Gamma Spectrometry The edible portions of fish samples from both locations were analyzed for gamma-emitting nuclides. Naturally-occurring K-40 was found in all fish samples. Concentrations ranged from 2,538 to 4,277 pCi/kg wet and was consistent with levels detected in previous years. No fission or activation products were detected. (Table C-IV.2, Appendix C)

7. Sediment Aquatic sediment samples were collected at three locations (A1-3, J2-1 and K1-3) semiannually. Of these locations two (J2-1 and K1-3) could be affected by TMINS effluent releases. The following analysis was performed:

Gamma Spectrometry Sediment samples from all locations were analyzed for gamma-emitting nuclides. Potassium-40 was found in all sediment samples and ranged from 6,795 to 12,280 pCi/kg dry. Cs-137 is occasionally found in sediment at very low levels (just above LLD) and is not distinguishable from background levels. (Figure C-5, Appendix C) No other fission or activation products were detected.

(Table C-V.1, Appendix C)

B. Atmospheric Environment

1. Airborne Particulates

a. Air Particulates Continuous air particulate samples were collected from seven locations on a weekly basis. Six locations (A3-1, E1-2, F1-3, G2-1, H3-1 and M2-1) were indicator stations located in the highest D/Q sectors and the nearest communities to TMI. One sample (Q15-1) represents the control location at a remote distance from TMINS. The following analyses were performed:

Gross Beta Weekly samples were analyzed for concentrations of beta emitters. Detectable gross beta activity was observed at all locations. (Table C-VI.1 and C-VI.2, Appendix C)

Comparison of results aid in determining the effects, if any, resulting from the operation of TMINS. The results from the closest to the site boundary locations (Group I) ranged from 6 to 28E-3 pCi/m3 with a mean of 13E-3 pCi/m3. The results from the intermediate offsite locations (Group II) ranged from 5 to 29E-3 pCi/m3 with a mean of 13E-3 pCi/m3. The results from the Control location (Group III) ranged from 6 to 28E-3 pCi/m3 with a mean of 15E-3 pCi/m3. Comparison of the 2020 air particulate data with previous years data indicate no effects from the operation of TMINS (Figure C-6, Appendix C). In addition, a comparison of the weekly mean values for 2020 indicate no notable differences between indicator and control stations. (Figure C-7, Appendix C)

Gamma Spectrometry Weekly samples were composited quarterly and analyzed for gamma-emitting nuclides. Naturally-occurring Be-7 due to cosmic ray activity was detected in all 28 samples. These concentrations ranged from 39 to 88E-3 pCi/m3. All other nuclides were less than MDC. (Table C-VI.3, Appendix C)

b. Airborne Iodine Continuous air samples were collected from seven (A3-1, E1-2, F1-3, G2-1, H3-1, M2-1 and Q15-1) locations and analyzed weekly for I-131. All results were less than the MDC for I-131.

(Table C-VII.1, Appendix C)

2. Terrestrial

a. Milk Samples were collected from four locations (K15-3, F4-1, G2-1 and P4-1) biweekly March through November and monthly December through February. The following analyses were performed:

Iodine-131 Milk samples from all locations were analyzed for concentrations of I-131. All results were less than the MDC.

(Table C-VIII.1, Appendix C)

Strontium Milk samples from all locations were composited quarterly and analyzed for Sr-89 and Sr-90. No Sr-89 or Sr-90 activity was detected. (Table C-VIII.2, Appendix C) The results are consistent with those detected in the pre-operational years.

(Figure C-8, Appendix C)

Gamma Spectrometry Milk samples from all locations were analyzed for concentrations of gamma-emitting nuclides. Naturally-occurring K-40 activity was found in all samples. The concentrations ranged from 777 to 1,625 pCi/L. All other nuclides were less than the MDC.

(Table C-VIII.3, Appendix C).

b. Food Products Food products were collected monthly at three locations (B10-2, E1-2 and H1-2), in lieu of milk sampling, and annually from the four food product groups at two locations (B10-2 and E1-2). B10-2 was the control location for both annual and monthly sampling.

The following analyses were performed:

Strontium Six food product samples were analyzed for concentrations of Sr-90. No Sr-90 activity was detected in any sample.

(Table C-IX.1, Appendix C)

Gamma Spectrometry Each food product sample was analyzed for concentrations of gamma-emitting nuclides. Naturally-occurring Be-7 due to cosmic ray activity was detected in 15 of 42 samples with concentrations ranging from 444 to 1,5197pCi/kg. Naturally-occurring K-40 activity was found in all samples. The concentrations ranged from 1,310 to 8,717 pCi/kg. All other nuclides were less than the MDC.

(Table C-IX.1, Appendix C)

C. Ambient Gamma Radiation Ambient gamma radiation levels were measured utilizing Optically Stimulated Luminescence Dosimeter (OSLD). Ninety OSLD locations were established around the site. Results of OSLD measurements are listed in Tables C-X.1 to C-X.3, Appendix C.

All of the OSLD measurements were below 32 mR/quarter, with a range of 11.1 to 31.1 mR/standard quarter. A comparison of the Site Boundary and Indicator data to the Control Location data, indicate that the ambient gamma radiation levels from the Control Locations D15-1, F25-1, G10-1, G15-1, H15-1, J15-1, K15-1, L15-1, N15-2, Q15-1 and R15-1 averaged higher than indicator stations. Locations D15-1, F25-1, G10-1, G15-1, H15-1, J15-1, K15-1, L15-1, N15-2, Q15-1 and R15-1 have a historical high bias, and this bias is most likely due to radon and other naturally-occurring nuclides, e.g. K-40, emanating from the ground.

D. Land Use Survey A Land Use Survey conducted in the 2020 fall growing season around the Three Mile Island Nuclear Station (TMINS) was performed by Exelon Industrial Services (EIS) for Exelon to comply with TMI-2 Tech Spec 6.7.2.b and Section 8.2 of the Plant's Offsite Dose Calculation Manual (ODCM). The purpose of the survey was to document the nearest resident, milk-producing animal and garden of greater than 500 ft2 in each of the sixteen 221/2 degree sectors around the site. The results of these surveys are summarized below:

Distance in Miles from the TMINS Reactor Buildings Residence Garden Milk Farm Sector Miles Miles Miles A N 1.0 1.9 2.1 B NNE 0.8 1.2 -

C NE 0.5 1.1 4.2 D ENE 0.5 0.5 4.5 E E 0.4 0.5 1.1 F ESE 1.1 0.5 3.2 G SE 0.7 0.6 1.4 H SSE 0.7 0.8 -

J S 2.2 2.5 -

K SSW 0.6 1.6 4.9, 14.4 L SW 0.5 1.7 -

M WSW 1.2 1.3 -

N W 1.2 1.3 -

P WNW 1.1 1.7 3.7 Q NW 1.1 1.2 -

R NNW 1.1 2.4 -

E. Radiological Impact of TMINS Operations An assessment of potential radiological impact indicated that radiation doses to the public from 2020 operations at TMINS were well below all applicable regulatory limits and were significantly less than doses received from natural sources of radiation. The 2020 whole body dose potentially received by an assumed maximum exposed individual from TMI-1 and TMI-2 liquid and airborne effluents was conservatively calculated to be 0.05 mrem. This dose is equivalent to 0.02% of the dose that an individual living in the TMI area receives each year from natural background radiation.

1. Determination of Radiation Doses to the Public Dose assessments can be performed by using either effluent data and an environmental transport model or environmental sample data. To the extent possible, doses to the public are based on the direct measurement of dose rates from external sources and the measurement of radionuclide concentrations in environmental media which may contribute to an internal dose of radiation. Optically Stimulated Luminescent Dosimetry (OSLDs) positioned in the environment around TMINS provide measurements to determine external radiation doses to humans. Samples of air, water and food products are used to determine internal doses.

The quantity of radioactive materials released during normal operations are typically too small to be measured once distributed in the offsite environment. Therefore, the potential offsite doses are more effectively calculated for TMINS operations using a computerized model that predicts concentrations of radioactive materials in the environment and subsequent radiation doses based on measured effluents.

Doses are calculated using a model that incorporates the guidelines and methodology set forth by the USNRC in Regulatory Guide 1.109 and NUREG 0133. Due to the conservative assumptions that are used in the model, the calculated doses are generally higher than the doses based on actual environmental sample concentrations.

Therefore, the model predicts doses that are higher than actual doses received by people. The type and amount of radioactivity released from TMINS is calculated using measurements from effluent sample analyses.

Airborne releases are diluted and carried away from the site by atmospheric diffusion, which continuously acts to disperse radioactivity.

Variables that affect atmospheric dispersion include wind speed, temperature at different elevations, terrain, and shift in wind direction. A weather station on the north end of TMI is linked to a data logger that records the meteorological data.

Computer models also are used to predict the downstream dilution and travel times for liquid releases into the Susquehanna River. Actual monthly Susquehanna River flows are obtained from the USGS Stream gauging station 01570500 located at Harrisburg, PA.

The human exposure pathways also are included in the model and are depicted in Figure 1. The exposure pathways that are considered for the discharge of TMINS liquid effluents are consumption of drinking water and fish. The exposure pathways considered for the discharge of TMINS airborne effluents are plume exposure, inhalation, cow milk consumption, fruit and vegetable consumption, and meat consumption.

When determining the dose to humans, it is necessary to consider all applicable pathways and all exposed tissues, summing the dose from each to provide the total dose for each organ as well as the whole body from a given radionuclide. Dose calculations involve determining the energy absorbed per unit mass in the various tissues. Thus, for radionuclides taken into the body, the metabolism of the radionuclide in the body must be known along with the physical characteristics of the nuclide such as energies, types of radiations emitted and half-life. The dose assessment model also contains dose conversion factors for the radionuclides for each of four age groups (adults, teenagers, children and infants) and eight organs (total body, thyroid, liver, skin, kidney, lung, bone and GI tract).

2. Result of Dose Calculations The maximum hypothetical doses due to 2020 TMI-1 and TMI-2 liquid and airborne effluents are summarized in Tables 1 and 2. Table 1 compares the calculated maximum hypothetical individual doses to the USNRC 10 CFR 50 App. I guidelines. This table also compares the calculated doses (to an individual of the public) from effluents and direct radiation to USEPA 40 CFR 190 dose limits. Table 2 presents the maximum hypothetical whole body doses to an individual. As shown in Table 1, the doses calculated for 2020 operations at TMINS were well below the Federal dose limits (USEPA 40 CFR 190) and the guidelines of USNRC 10 CFR 50 App. I. This conclusion was supported by radionuclide concentrations detected in actual environmental samples.

Doses from natural background radiation provide a baseline for assessing the potential public health significance of radioactive effluents.

Natural background radiation from cosmic, terrestrial and natural radionuclides in the human body (not including radon), averages about 81 mrem/yr (Ref. 5). Additionally, the average individual living in the United States receives an annual dose of about 2,760 mrem to the lung from natural radon gas. This lung dose is considered to be equivalent to a whole (or total) body dose of 230 mrem (Ref. 5). Therefore, the average person in the United States receives a whole body dose of about 311 mrem/yr from natural background radiation sources.

As shown on Table 2, the maximum hypothetical whole body dose received by an individual from 2020 TMI-1 and TMI-2 liquid and airborne effluents combined was conservatively calculated to be 0.05 mrem. This dose is equivalent to 0.02% percent of the dose that an individual living in the TMI area receives each year from natural background radiation (311 mrem).

The low doses calculated for 2020 TMINS operations were the result of efforts to maintain releases "as low as reasonably achievable" (ALARA).

In conclusion, radioactive materials related to 2020 TMINS operations were detected in environmental samples, but the measured concentrations were low and consistent with measured effluents. The environmental sample results verified that the doses received by the public from TMINS effluents in 2020 were well below applicable dose limits and only a small fraction of the doses received from natural background radiation. Additionally, the results indicated that there was no permanent buildup of radioactive materials in the environment and no increase in background radiation levels.

Therefore, based on the results of the radiological environmental monitoring program (REMP) and the doses calculated from measured effluents, TMINS operations in 2020 did not have any adverse effects on the health of the public or on the environment.

TABLE 1 Calculated Maximum Hypothetical Doses to an Individual from 2020 TMI-1 and TMI-2 Liquid and Airborne Effluents Maximum Hypothetical Doses To An Individual USNRC 10 CFR 50 APP. I Calculated Dose Guidelines (mrem/yr)

(mrem/yr) TMI-1 TMI-2 From Radionuclides 3 total body, or 2.10E-02 4.74E-04 In Liquid Releases 10 any organ 2.69E-02 7.54E-04 From Radionuclides In 5 total body, or 0* 0*

Airborne Releases (Noble Gases) 15 skin 0* 0*

From Radionuclides In Airborne 15 any organ 2.39E-02 4.62E-05 Releases (Iodines, Tritium and Particulates)

• No noble gases were released from TMI-2.

USEPA Calculated Dose 40 CFR 190 (mrem/yr)

Limits TMI-1 and TMI-2 (mrem/yr) Combined**

Total from Site 75 thyroid 0.034 25 total body 0.052 or other organs

• *This sums together TMI-1 and TMI-2 maximum doses regardless of age group for different pathways.

The combined doses include those due to radioactive effluents and direct radiation from TMINS. The direct radiation dose is calculated from environmental dosimeter data. For this calculation, exposure is assumed to be equal to dose.

The direct radiation dose from 2020 TMINS operations was 0.00 mrem/yr based on calculations from ANSI/HI Standard N13.37.

TABLE 2 Calculated Whole Body Doses to the Maximum Individual from 2020 TMI-1 and TMI-2 Liquid and Airborne Effluents Calculated Maximum Individual Whole Body Dose (mrem/yr)

TMI-1 TMI-2 From Radionuclides In Liquid Releases 2.10E-02 4.74E-04 From Radionuclides in Airborne Releases 0* 0*

(Noble Gases)

From Radionuclides In Airborne 2.39E-02 4.62E-05 Releases (Iodines, Tritium and Particulates)

• No noble gases were released from TMI-2.

Individual Whole Body Dose Due to TMI-1 and TMI-2 Operations: 0.05 mrem/yr Individual Whole Body Dose Due to Natural Background Radiation (1) 311 mrem/yr (1) NCRP 160 - (2009)

Figure 1 Expo ure Pathway s For Radionuclides Routinely Released From TMI S

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'PREDOMINANT RADION UCLIDES I

NOBLE GASES {Xe ,Kr) ACTIVATION PRODUCTS (Co -60, Mo-54)

P lu e exposure Shore line exposure RADlOIOO{N ES ll- 13!, I- lH) RADIOCES!lJMS Cs- 134. Cs- 13 )

l nbaiat'on and consumption of mi l k , Shoreline exposure an con:rnmptiou of m il * .

water fruit;; , a nd vegeta !es me at . fish, water , fr u its, and veg e tab les RADIO TRON1 IUMS r-89, S r-90) TRITIU ( H- J)

Con umpfio n of mi lk, m~a l, ln hal:Hil'.ln a d cons tnpt io n of water, fru its, an d ve *etables milk. fr uit:;, and vege ab le:;

F. Errata Data In the 2019 AEROR, an incorrect Issue Report number (IR 4240350) was referenced for a missed surface water sample at Station J1-2 due to the sample line being pulled into the river and disconnected. The correct IR number should have been IR 4240530.

G. Summary of Results - Inter-Laboratory Comparison Program The primary and other secondary laboratories analyzed Performance Evaluation (PE) samples of air particulate, air iodine, milk, soil, vegetation and water matrices (Appendix E). The PE samples, supplied by Analytics Inc., Environmental Resource Associates (ERA) and DOEs MAPEP, were evaluated against the following pre-set acceptance criteria:

1. 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-ES evaluates the reported ratios based on internal QC requirements, which are based on the DOE MAPEP criteria.

2. 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, NELAC, state specific 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.

3. DOE Evaluation Criteria MAPEPs evaluation report provides an acceptance range with associated flag values.

The MAPEP defines three levels of performance: Acceptable (flag =

A), Acceptable with Warning (flag = W), and Not Acceptable (flag =

N). Performance is considered acceptable when a mean result for the specified analyte is +/- 20% of the reference value. Performance is acceptable with warning when a mean result falls in the range from

+/-20% to +/-30% of the reference value (i.e., 20% < bias < 30%). If the bias is greater than 30%, the results are deemed not acceptable.

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.

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:

1. The MAPEP February 2020 AP U-233/234 and U-238 results were evaluated as Not Acceptable. The reported value for U-233/234 was 0.0416 +/- 0.0102 Bq/sample and the known result was 0.075 Bq/sample (acceptance range 0.053 - 0.098). The reported value for U-238 was 0.0388 +/- 0.00991 Bq/sample and the known result was 0.078 Bq/sample (acceptance range 0.055 - 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)

2. The Analytics September 2020 milk Sr-89 result was evaluated as Not Acceptable. The reported value was 62.8 pCi/L and the 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 2013 and there have only been 3 upper/lower boundary warnings 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 the known.

(NCR 20-19)

3. The ERA October 2020 water I-131 result was evaluated as Not Acceptable. The reported value was 22.9 pCi/L and the known result 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)

4. The ERA October 2020 water Gross Alpha and Gross Beta results were evaluated as Not Acceptable. The reported/acceptable values 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 20-18)

5. The MAPEP August 2020 soil Ni-63 result was evaluated as Not Acceptable. The reported value was 438 +/- 21.1 Bq/kg and the known result was 980 Bq/kg (acceptance range 686 - 1274). It is believed that some Ni-63 loss occurred during the sample prep step.

(NCR 20-20)

For the secondary QC samples, EIS laboratory, analyzed gross beta, gramma, and I-131 for TMINS. 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:

1. The ERA April 2020 reported Gross Beta result was 43.3 pCi/L and the known was 60.5 pCi/L (acceptance range was 41.7 - 67.2 pCi/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 delivery of the sample.

2. 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 135 pCi/L 190 pCi/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.

For the secondary QC samples, GEL laboratory analyzed only H-3 and (water matrix) for TMINS REMP & RGPP. GEL also analyzed Sr-89/90, gross alpha and gamma nuclides for the RGPP. For these analyses, 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:

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

a. The H-3 reported value of 15,200 pCi/L were evaluated as Not Acceptable. The known result was 17,800 pCi/L with an acceptance range of 15,600 - 19,600 pCi/L. All data and lab 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.

b. Two Sr-89 results were evaluated as Not Acceptable. The reported values were 73.3 pCi/L and 70.8 pCi/L. The known result was 59.3 pCi/L, with an acceptance range of 47.6 - 67.1 pCi/L. A review of the data as well as of the preparation 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 criteria of +/- 25% for Laboratory Control Samples.

c. The I-131 reported value of 23.7 pCi/L was evaluated as Not Acceptable. The known result was 29.9 pCi/L with an acceptance range of 24.9 - 34.9 pCi/L. The laboratory 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.

No permanent corrective actions/preventative actions or 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.

2. Two ERA 2nd quarter 2020 water Sr-89 results were evaluated as Not Acceptable. The reported values were 68.8 and 71.6 pCi/L and the known result was 60.1 pCi/L (acceptance range of 48.3 -

67.9 pCi/L). No Corrective Action information was included in the 2020 QA Report.

3. CARR 200902-1287 - The ERA 3rd quarter 2020 water Co-60 result was evaluated as Not Acceptable. The reported value was 97.9 pCi/L and the known result was 86.1 pCi/L (acceptance range of 77.5 - 97.0 pCi/L). The data was reviewed and no anomalies were noted. The 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 No permanent corrective actions/preventative actions or 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.

V. References

1. Three Mile Island Nuclear Station, Unit 1, Technical Specifications, DPR 50.

2. Three Mile Island Nuclear Station, Unit 2, PDMS Technical Specifications, DPR 73.

3. Radiation Management Corporation. Three Mile Island Nuclear Station, Preoperational Radiological Environmental Monitoring Program, January 1, 1974 - June 5, 1974. RMC-TR-75-17, January 1975.

4. Exelon. Three Mile Island Nuclear Station Offsite Dose Calculation Manual (ODCM).

5. National Council of Radiation Protection and Measurements Report No. 160.

Ionizing Radiation Exposure of the Population of the United States. 2009 Intentionally left blank Intentionally left blank Intentionally left blank APPENDIX A RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT

SUMMARY

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

SUMMARY

FOR THE THREE MILE ISLAND NUCLEAR STATION, 2020 NAME OF FACILITY: THREE MILE ISLAND NUCLEAR STATION DOCKET NUMBER: 50-289 & 50-320 LOCATION OF FACILITY: MIDDLETOWN COUNTY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL MEDIUM OR REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) 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 24 2000 1082 <LLD 1082 J1-2 INDICATOR 0 (PCI/LITER) (10/12) (10/12) DOWNSTREAM OF TMINS LIQUID DISCHARGE OUTFALL 426 - 2910 426 - 2910 0.5 MILES S OF SITE I-131 12 1 NA <LLD - 0 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 ZR-95 30 <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 A-1 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 DRINKING WATER GR-B 36 4 3.1 3.3 3.8 Q9-1 CONTROL 0 (PCI/LITER) (15/24) (5/12) (5/12) STEELTON WATER COMPANY 2.0 - 5.3 1.9 - 4.1 1.9 - 4.1 8.5 MILES NW OF SITE I-131 36 1 <LLD <LLD - 0 H-3 36 2000 <LLD <LLD - 0 GAMMA 36 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 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 detectable measurement are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE THREE MILE ISLAND NUCLEAR STATION, 2020 NAME OF FACILITY: THREE MILE ISLAND NUCLEAR STATION DOCKET NUMBER: 50-289 & 50-320 LOCATION OF FACILITY: MIDDLETOWN COUNTY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL MEDIUM OR REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) 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 EFFLUENT WATER GR-B 12 4 2.9 NA 2.9 K1-1 INDICATOR 0 (PCI/LITER) (7/12) (7/12) RML-7 MAIN STATION DISCHARGE BLDG 2.5 - 3.6 2.5 - 3.6 0.2 MILES ONSITE I-131 (LOW LVL) 12 1 <LLD NA - 0 H-3 12 2000 11454 NA 11454 K1-1 INDICATOR 0 (10/12) (10/12) RML-7 MAIN STATION DISCHARGE BLDG 4030 - 20000 4030 - 20000 0.2 MILES ONSITE SR-89 2 5 <LLD NA - 0 SR-90 2 2 <LLD NA - 0 GAMMA 12 MN-54 15 <LLD NA - 0 A-2 CO-58 15 <LLD NA - 0 FE-59 30 <LLD NA - 0 CO-60 15 <LLD NA - 0 ZN-65 30 <LLD NA - 0 NB-95 15 <LLD NA - 0 ZR-95 30 <LLD NA - 0 CS-134 15 <LLD NA - 0 CS-137 18 <LLD NA - 0 BA-140 60 <LLD NA - 0 LA-140 15 <LLD NA - 0 BOTTOM FEEDER SR-90 4 10 <LLD <LLD - 0 (PCI/KGWET)

GAMMA 4 K-40 NA 2736 2773 2773 BKGB CONTROL 0 (2/2) (2/2) (2/2) CITY ISLAND 2538 - 2933 2671 - 2874 2671 - 2874 UPSTREAM 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 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 detectable measurement are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE THREE MILE ISLAND NUCLEAR STATION, 2020 NAME OF FACILITY: THREE MILE ISLAND NUCLEAR STATION DOCKET NUMBER: 50-289 & 50-320 LOCATION OF FACILITY: MIDDLETOWN COUNTY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL MEDIUM OR REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) 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 PREDATOR SR-90 4 10 <LLD <LLD - 0 (PCI/KGWET)

GAMMA 4 K-40 NA 3613 3557 3613 INDP INDICATOR 0 (2/2) (2/2) (2/2) YORK HAVEN DAM 2948 - 4277 3456 - 3657 2948 - 4277 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 CS-134 130 <LLD <LLD - 0 CS-137 150 <LLD <LLD - 0 A-3 SEDIMENT GAMMA 6 (PCI/KG DRY) K-40 NA 9968 7432 11640 J2-1 INDICATOR 0 (4/4) (2/2) (2/2) YORK HAVEN DAM 7858 - 12280 6795 - 8069 1100 - 12280 1.5 MILES S OF SITE MN-54 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 CS-134 150 <LLD <LLD - 0 CS-137 180 <LLD <LLD - 0 AIR PARTICULATE GR-B 364 10 13 15 15 Q15-1 CONTROL 0 (E-3 PCI/CU.METER) (311/313) (52/52) (52/52) WEST FAIRVIEW FIRE DEPT SOCIAL HALL 5 - 29 6 - 28 6 - 28 13.4 MILES NW OF SITE GAMMA 28 BE-7 NA 67 68 70 M2-1 INDICATOR 0 (24/24) (4/4) (4/4) FISHING CREEK; GOLDSBORO 38 - 94 56 - 80 59 - 81 1.3 MILES WSW OF SITE MN-54 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 NB-95 NA <LLD <LLD - 0 ZR-95 NA <LLD <LLD - 0 CS-134 50 <LLD <LLD - 0 CS-137 60 <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values. (F ) Fraction of detectable measurement are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE THREE MILE ISLAND NUCLEAR STATION, 2020 NAME OF FACILITY: THREE MILE ISLAND NUCLEAR STATION DOCKET NUMBER: 50-289 & 50-320 LOCATION OF FACILITY: MIDDLETOWN COUNTY, PA REPORTING PERIOD: 2020 INDICATOR CONTROL MEDIUM OR REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) 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 IODINE GAMMA 364 (E-3 PCI/CU.METER) I-131 70 <LLD <LLD - 0 MILK I-131 88 1 <LLD <LLD - 0 (PCI/LITER)

SR-89 16 5 <LLD <LLD - 0 SR-90 16 2 <LLD <LLD - 0 GAMMA 88 K-40 NA 1285 1068 1366 P4-1 INDICATOR 0 (66/66) (22/22) (22/22) FARM ON VALLEY ROAD 777 - 1625 852 - 1220 1141 - 1582 3.6 MILES WNW OF SITE CS-134 15 <LLD <LLD - 0 CS-137 18 <LLD <LLD - 0 A-4 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 VEGETATION SR-90 6 10 <LLD <LLD - 0 (PCI/KG WET)

GAMMA 42 BE-7 NA 825.7 876.5 947.9 H1-2 INDICATOR 0 (12/27) (3/15) (7/12) RED HILL MARKET 444 - 1527 820 - 930 444 - 1257 1.0 MILES SSE OF SITE K-40 NA 3960.9 4042.9 4328.9 E1-2 INDICATOR 0 (27/27) (15/15) (15/15) TMI VISITOR'S CENTER 1310 - 8717 1577 - 7134 1310 - 8717 0.4 MILES E OF SITE I-131 60 <LLD <LLD - 0 CS-134 60 <LLD <LLD - 0 CS-137 80 <LLD <LLD - 0 DIRECT RADIATION OSLD - QUARTERLY 360 NA 17.1 19.1 28.3 H8-1 INDICATOR 0 (MILLIREM/STD.MO.) (316/316) (44/44) (4/4) SAGINAW ROAD, STARVIEW 11.1 - 13.1 14.2 - 27.9 24.7 - 31.1 7.4 MILES SSE OF SITE (M) The Mean Values are calculated using the positive values. (F ) Fraction of detectable measurement are indicated in parentheses.

APPENDIX B LOCATION DESIGNATION, DISTANCE & DIRECTION, AND SAMPLE COLLECTION & ANALYTICAL METHODS B-1

Intentionally left blank B-2

TABLE B-1: Location Designation and Identification System for the Three Mile Island Nuclear Station XYYZ - General code for identification of locations, where:

X - Angular Sector of Sampling Location. The compass is divided into 16 sectors of 22 1/2 degrees each with center at Three Mile Island's Units 1 and 2 off-gas vents. Sector A is centered due North, and others are alphabetical in a clockwise direction.

YY - Radial Zone of Sampling Location in miles.

Z - Station's Numerical Designation within sector and zone, using 1, 2, 3... in each sector and zone.

B-3

TABLE B-2: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Three Mile Island Nuclear Station, 2020 Sample Station Map Distance Medium Code Number (miles) Azimuth Description AQS A1-3 1 0.6 359° N of site off north tip of TMI in Susquehanna River ID A1-4 1 0.3 6° N of Reactor Building on W fence adjacent to North Weather Station, TMI AP, AI, ID A3-1 2 2.7 357° N of site at Mill Street Substation SW A3-2 2 2.7 356° N of site at Swatara Creek, Middletown ID A5-1 2 4.4 3° N of site on Vine Street Exit off Route 283 ID A9-3 3 8.0 2° N of site at Duke Street Pumping Station, Hummelstown ID B1-1 1 0.6 25° NNE of site on light pole in middle of North Bridge, TMI ID B1-2 1 0.4 24° NNE of Reactor Building on top of dike, TMI ID B2-1 2 1.9 17° NNE of site on Sunset Dr. (off Hillsdale Rd.)

ID B5-1 2 4.9 19° NNE of site at intersection of School House and Miller Roads ID B10-1 3 9.2 21° NNE of site at intersection of West Areba Avenue and Mill Street, Hershey FP B10-2 3 10 31° NNE of site at Milton Hershey School, Hershey ID C1-1 1 0.7 37° NE of site along Route 441 N ID C1-2 1 0.3 50° NE of Reactor Building on top of dike, TMI ID C2-1 2 1.5 44° NE of site at Middletown Junction ID C5-1 2 4.7 43° NE of site on Kennedy Lane ID C8-1 3 7.1 48° NE of site at Schenk's Church on School House Road AQF Control - - - All locations where finfish are collected above Dock St.

Dam, Harrisburg ID D1-1 1 0.2 76° ENE of Reactor Building on top of dike, TMI ID D1-2 1 0.5 67° ENE of site off Route 441 along lane between garden center and residence ID D2-2 2 1.6 74° ENE of site along Hillsdale Rd. (S of Zion Rd.)

ID D6-1 3 5.2 66° ENE of site off Beagle Road ID D15-1 3 10.8 64° ENE of site along Route 241, Lawn AP, AI, ID, FP E1-2 1 0.4 97° E of site at TMI Visitor's Center ID E1-4 1 0.2 97° E of Reactor Building on top of dike, TMI M E2-2 2 1.1 96° E of site at farm on Pecks Road ID E2-3 2 2.0 97° E of site along Hillsdale Rd. (N of Creek Rd.)

ID E5-1 2 4.7 82° E of site at intersection of North Market Street (Route 230) and Zeager Road ID E7-1 3 6.7 88° E of site along Hummelstown Street, Elizabethtown ID F1-1 1 0.5 117° ESE of site near entrance to 500 kV Substation ID F1-2 1 0.2 112° ESE of Reactor Building on top of dike midway within ISWSF, TMI AP, AI F1-3 1 0.6 112° ESE of site in 500 kV Substation ID F1-4 1 0.2 122° ESE of Reactor Building on top of dike, TMI ID F2-1 2 1.3 119° ESE of site along Engle Road M F4-1 2 3.2 104° ESE of site at farm on Turnpike Road ID F5-1 2 4.7 109° ESE of site along Amosite Road ID F10-1 3 9.4 112° ESE of site along Donegal Springs Road, Donegal Springs ID F25-1 3 22 106° ESE of site at intersection of Steel Way and Loop Roads, Lancaster ID G1-2 1 0.7 145° SE of site along Route 441 S ID G1-3 1 0.2 130° SE of Reactor Building on top of dike, TMI ID G1-5 1 0.3 143° SE of Reactor Building on top of dike, TMI ID G1-6 1 0.3 139° SE of Reactor Building on top of dike, TMI AI, AP, M G2-1 2 1.4 126° SE of site at farm on Becker Road ID G2-4 2 1.7 138° SE of site on Becker Road ID G5-1 2 4.8 131° SE of site at intersection of Bainbridge and Risser Roads ID G10-1 3 9.7 128° SE of site at farm along Engles Tollgate Road, Marietta ID G15-1 3 14.4 126° SE of site at Columbia Water Treatment Plant DW G15-2 3 13.3 129° SE of site at Wrightsville Water Treatment Plant DW G15-3 3 15.7 124° SE of site at Lancaster Water Treatment Plant B-4

TABLE B-2: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Three Mile Island Nuclear Station, 2020 Sample Station Map Distance Medium Code Number (miles) Azimuth Description ID H1-1 1 0.5 167° SSE of site, TMI FP H1-2 1 1.0 151° SSE of site along Route 441, Red Hill Market AP, AI, ID H3-1 2 2.2 160° SSE of site in Falmouth-Collins Substation ID H5-1 2 4.1 158° SSE of site by Guard Shack at Brunner Island Steam Electric Station ID H8-1 3 7.4 163° SSE of site along Saginaw Road, Starview ID H15-1 3 13.2 157° SSE of site at intersection of Orchard and Stonewood Roads, Wilshire Hills AQF Indicator - - - All locations where finfish are collected downstream of the TMINS liquid discharge outfall ID J1-1 1 0.8 176° S of site, TMI SW J1-2 1 0.5 188° S of site downstream of the TMINS liquid discharge outfall in Susquehanna River ID J1-3 1 0.3 189° S of Reactor Building just S of SOB, TMI AQS J2-1 2 1.4 179° S of site in Susquehanna River just upstream of the York Haven Dam ID J3-1 2 2.7 179° S of site at York Haven/Cly ID J5-1 2 4.9 181° S of site along Canal Road, Conewago Heights ID J7-1 3 6.5 176° S of site off of Maple Street, Manchester ID J15-1 3 12.6 183° S of site in Met-Ed York Load Dispatch Station EW K1-1 1 0.2 211° On site at RML-7 Main Station Discharge Building AQS K1-3 1 0.2 213° SSW of site downstream of the TMINS liquid discharge outfall in the Susquehanna River ID K1-4 1 0.2 209° SSW of Reactor Building on top of dike behind Warehouse 2, TMI ID K2-1 2 1.2 200° SSW of site on S Shelley Island ID K3-1 2 2.0 206° SSW of site along Rt. 262, N of Cly ID K5-1 2 4.9 202° SSW of site along Conewago Creek Road, Strinestown ID K8-1 3 7.5 196° SSW of site at intersection of Coppenhaffer Road and Route 295, Zions View ID K15-1 3 12.8 203° SSW of site behind McDonalds and next to child care center, Weiglestown M K15-3 3 14.4 205° SSW of site at farm along S Salem Church Rd, Dover ID L1-1 1 0.1 236° SW of site on top of dike W of Mech. Draft Cooling Tower, TMI ID L1-2 1 0.5 221° SW of site on Beech Island ID L2-1 2 1.8 224° SW of site along Route 262 ID L5-1 2 4.1 228° SW of site at intersection of Stevens and Wilson Roads ID L8-1 3 8.0 225° SW of site along Rohlers Church Rd., Andersontown ID L15-1 3 11.8 226° SW of site on W side of Route 74, rear of church, Mt.

Royal ID M1-1 1 0.1 249° WSW of Reactor Building on SE corner of U-2 Screenhouse fence, TMI ID M1-2 1 0.4 252° WSW of site on E side of Shelley Island, Lot #157 AP, AI, ID M2-1 2 1.3 256° WSW of site along Route 262 and adjacent to Fishing Creek, Goldsboro ID M5-1 2 4.3 249° WSW of site at intersection of Lewisberry and Roxberry Roads, Newberrytown ID M9-1 3 8.7 243° WSW of site along Alpine Road, Maytown ID N1-1 1 0.7 274° W of site on W side of Shelley Island, between lots #13 and #14 ID N1-3 1 0.1 274° W of Reactor Building on fence adjacent to Screenhouse entrance gate, TMI ID N2-1 2 1.2 261° W of site at Goldsboro Marina ID N5-1 2 4.9 268° W of site off of Old York Road along Robin Hood Drive ID N8-1 3 7.7 262° W of site along Route 382, 1/2 mile north of Lewisberry ID N15-2 3 10.4 275° W of site at intersection of Lisburn Road and Main Street, Lisburn ID P1-1 1 0.4 303° WNW of site on Shelley Island B-5

TABLE B-2: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Three Mile Island Nuclear Station, 2020 Sample Station Map Distance Medium Code Number (miles) Azimuth Description ID P1-2 1 0.1 292° WNW of Reactor Building on fence N of Unit 1 Screenhouse, TMI ID P2-1 2 1.9 283° WNW of site along Route 262 M P4-1 2 3.6 295° WNW of site at farm on Valley Road ID P5-1 2 5.0 284° WNW of site at intersection of Valley Road (Route 262) and Beinhower Road ID P8-1 3 7.9 292° WNW of site along Evergreen Road, Reesers Summit ID Q1-1 1 0.5 317° NW of site on E side of Shelley Island ID Q1-2 1 0.2 321° NW of Reactor Building on fence W of Warehouse 1, TMI ID Q2-1 2 1.9 310° NW of site along access road along river ID Q5-1 2 5.0 317° NW of site along Lumber Street, Highspire SW, DW, ID Q9-1 3 8.5 310° NW of site at the Steelton Water Company AP, AI, ID Q15-1 3 13.4 309° NW of site behind West Fairview Fire Dept. Social Hall (abandoned)

ID R1-1 1 0.2 335° NNW of Reactor Building along W fence, TMI ID R1-2 1 0.7 334° NNW of site on central Henry Island ID R3-1 2 2.6 341° NNW of site at Crawford Station, Middletown ID R5-1 2 4.9 339° NNW of site at intersection of Spring Garden Drive and Route 441 ID R9-1 3 8.0 341° NNW of site at intersection of Derry and 66th Streets, Rutherford Heights ID R15-1 3 11.2 332° NNW of site at intersection of Route 22 and Colonial Road, Colonial Park IDENTIFICATION KEY ID = Immersion Dose (OSLD) EW = Effluent Water SW = Surface Water DW = Drinking Water AI = Air Iodine M = Milk (Cow)

AP = Air Particulate AQF = Finfish FP = Food Products (Green Leafy AQS = Aquatic Sediment Vegetation, Fruits, Vegetables)

B-6

TABLE B-3: Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Three Mile Island Nuclear Station, 2020 Sample Analysis Sampling Method Collection Procedure Number Sample Size Analytical Procedure Number Medium Monthly composite CY-ES-240 EIS Collection of Surface- TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Surface Gamma from a continuous Drinking-Effluent Water Samples for 2 gallon Water Spectroscopy EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the water compositor Radiological Analysis (TMI) Genie PC Counting System Monthly composite CY-ES-240 EIS Collection of Surface- TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Various Surface Gross Beta from a continuous Drinking-Effluent Water Samples for 2 gallon Matrices Water water compositor Radiological Analysis (TMI) EIS, CY-ES-206 Operation of the Tennelec S5E Proportional Counter Surface Monthly composite CY-ES-240 EIS Collection of Surface- TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation Tritium from a continuous Drinking-Effluent Water Samples for 2 gallon Water water compositor Radiological Analysis (TMI) GEL, EPA 906.0 Mod, for Tritium analysis by Liquid scintillation Monthly composite CY-ES-240 EIS Collection of Surface- TBE, TBE-2012 Radioiodine in Various Matrices Surface Iodine-131 2 gallon B-7 Water from a continuous Drinking-Effluent Water Samples for EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the water compositor Radiological Analysis (TMI) Genie PC Counting System Drinking Monthly composite CY-ES-240 EIS Collection of Surface-Gross Beta 2 gallon TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Various Water from a continuous Drinking-Effluent Water Samples for Matrices water compositor Radiological Analysis (TMI)

Drinking Gamma Monthly composite CY-ES-240 EIS Collection of Surface-from a continuous Drinking-Effluent Water Samples for 2 gallon TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Water Spectroscopy water compositor Radiological Analysis (TMI)

Drinking Monthly composite CY-ES-240 EIS Collection of Surface-Iodine-131 from a continuous Drinking-Effluent Water Samples for 2 gallon TBE, TBE-2012 Radioiodine in Various Matrices Water water compositor Radiological Analysis (TMI)

Drinking Monthly composite CY-ES-240 EIS Collection of Surface-Tritium from a continuous Drinking-Effluent Water Samples for 2 gallon TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation Water water compositor Radiological Analysis (TMI)

Effluent Monthly composite CY-ES-240 EIS Collection of Surface-Iodine-131 from a continuous Drinking-Effluent Water Samples for 2 gallon TBE, TBE-2012 Radioiodine in Various Matrices Water water compositor Radiological Analysis (TMI)

Effluent Gamma Monthly composite CY-ES-240 EIS Collection of Surface-2 gallon TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Water Spectroscopy from a continuous Drinking-Effluent Water Samples for water compositor Radiological Analysis (TMI)

TABLE B-3: Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Three Mile Island Nuclear Station, 2020 Sample Analysis Sampling Method Collection Procedure Number Sample Size Analytical Procedure Number Medium Effluent Monthly composite CY-ES-240 EIS Collection of Surface-Tritium from a continuous Drinking-Effluent Water Samples for 2 gallon TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation Water water compositor Radiological Analysis (TMI)

Effluent Strontium- Semi-annual TBE, TBE-2023 Compositing of 2 gallon Water 89/90 composite from TBE, TBE-2018 Radiostrontium Analysis by Chemical Separation Samples monthly samples Gamma CY-ES-240 EIS Collection of Surface-Storm Water Quarterly composite of 1 gallon Spectroscopy Drinking-Effluent Water Samples for TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis monthly grab samples Radiological Analysis (TMI)

CY-ES-240 EIS Collection of Surface-Storm Water Tritium Quarterly composite of 1 gallon Drinking-Effluent Water Samples for TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation monthly grab samples Radiological Analysis (TMI)

B-8 Semi-annual samples TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Gamma collected via ER-TMI-13 Collection of fish samples 1000 grams Fish Spectroscopy electroshocking or for radiological analysis (TMINS) (wet) EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the other techniques Genie PC Counting System Semi-annual samples 1000 grams TBE, TBE-2018 Radiostrontium Analysis by Chemical Separation Fish Strontium-90 collected via ER-TMI-13 Collection of fish samples electroshocking or for radiological analysis (TMINS) (wet)

GEL, EPA 905.0 Mod/DOE RP501 Rev. 1 Mod other techniques TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Gamma ER-TMI-03 Collection of sediment 500 grams Sediment Semi-annual grab Spectroscopy samples for radiological analysis (dry) EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the samples (TMINS) Genie PC Counting System TBE, TBE-2023 Compositing of TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis 13 filters Air Gamma Quarterly composite of Samples (approx.. 3600 Particulates Spectroscopy each station EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the CY-ES-204 Sample Preparation for cubic meters)

Gamma and Beta Counting Genie PC Counting System One-week composite 1 filter TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Various Air CY-ES-237 Collection of Air Iodine & (approx.. 280 Gross Beta of continuous air Matrices Particulates Air Particulate for Radiological Analysis cubic meters sampling through glass (TMI) weekly) fiber filter paper CY-ES-206 Operation of the Tennelec S5E Proportional Counter

TABLE B-3: Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Three Mile Island Nuclear Station, 2020 Sample Analysis Sampling Method Collection Procedure Number Sample Size Analytical Procedure Number Medium One-week composite 1 filter TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Gamma CY-ES-237 Collection of Air Iodine &

Air Iodine of continuous air (approx. 280 Spectroscopy Air Particulate for Radiological Analysis sampling through cubic meters EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the (TMI) charcoal filter weekly) Genie PC Counting System Bi-weekly grab TBE, TBE-2012 Radioiodine in Various Matrices Milk I-131 sample when cows CY-ES-238 Sample Collection for 2 gallon are on pasture. Radiological Analysis - Milk (TMI) EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the Monthly all other times Genie PC Counting System TBE, TBE-2023 Compositing of Quarterly composite of Samples TBE, TBE-2019 Radiostrontium Analysis by Ion Exchange Milk Sr-89/90 bi-weekly and monthly 2 gallon CY-ES-238 Sample Collection for grab samples GEL, EPA 905.0 Mod/DOE RP501 Rev. 1 Mod Radiological Analysis - Milk (TMI)

B-9 Bi-weekly grab TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Gamma sample when cows CY-ES-238 Sample Collection for Milk 2 gallon Spectroscopy are on pasture. Radiological Analysis - Milk (TMI) EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the Monthly all other times Genie PC Counting System TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Gamma Monthly and annual CY-ES-241 Sample Collection for Vegetation 1000 grams Spectroscopy grab sample Gamma Counting - Vegetation (TMI) EIS, CY-ES-205 Gamma Counting Using the HPGe Detector with the Genie PC Counting System Strontium- TBE, TBE-2018 Radiostrontium Analysis by Chemical Separation Vegetation Monthly and annual CY-ES-241 Sample Collection for 1000 grams 89/90 grab sample Gamma Counting - Vegetation (TMI)

GEL, EPA 905.0 Mod/DOE RP501 Rev. 1 Mod Optically Quarterly OSLDs comprised of two CY-ES-239 Collection of OSLD OSLD Stimulated 2 badges with Al2O3:C Landauer samples for radiological analysis Landauer Incorporated Luminescence 3 dosimeters Incorporated elements. (TMINS)

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Figure B-1 Environmental Sampling Locations Within One Mile of the Three Mile Island Nuclear Station, 2020

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\,.., h l<t"'1 Figure B-3 Environmental Sampling Locations Greater than Five Miles of the Three Mile Island Nuclear Station, 2020

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 THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD J1-2 Q9-1 01/02/20 - 01/30/20 < 170 < 175 01/30/20 - 02/27/20 < 181 < 185 02/27/20 - 04/01/20 426 +/- 135 < 193 04/01/20 - 04/29/20 673 +/- 134 < 165 04/29/20 - 05/28/20 788 +/- 150 < 178 05/28/20 - 06/30/20 2910 +/- 350 < 177 06/30/20 - 07/30/20 1220 +/- 192 < 182 07/30/20 - 09/02/20 1150 +/- 183 < 173 09/02/20 - 10/01/20 949 +/- 162 < 175 10/01/20 - 10/29/20 1240 +/- 200 < 187 10/29/20 - 12/03/20 747 +/- 149 < 179 12/03/20 - 12/29/20 712 +/- 148 < 183 MEAN +/- 2 STD DEV 1082 +/- 1389 -

Table C-I.2 CONCENTRATIONS OF I-131 IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD A3-2 01/02/20 - 01/30/20 < 0.9 01/30/20 - 02/27/20 < 0.8 02/27/20 - 04/01/20 < 0.7 04/01/20 - 04/29/20 < 0.7 04/29/20 - 05/28/20 < 0.7 05/28/20 - 06/30/20 < 0.6 06/30/20 - 07/30/20 < 0.7 07/30/20 - 09/02/20 < 0.8 09/02/20 - 10/01/20 < 0.9 10/01/20 - 10/29/20 < 0.9 10/29/20 - 12/03/20 < 0.9 12/03/20 - 12/29/20 < 0.9 MEAN -

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

Table C-I.3 CONCENTRATIONS OF GAMMA EMITTERS IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR 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 J1-2 01/02/20 - 01/30/20 < 7 < 8 < 14 < 5 < 15 < 7 < 12 < 7 < 7 < 29 < 11 01/30/20 - 02/27/20 < 6 < 6 < 12 < 6 < 10 < 6 < 12 < 8 < 7 < 30 < 10 02/27/20 - 04/01/20 < 6 < 5 < 12 < 7 < 13 < 5 < 11 < 5 < 6 < 27 < 13 04/01/20 - 04/29/20 < 6 < 8 < 12 < 8 < 13 < 6 < 13 < 10 < 7 < 34 < 11 04/29/20 - 05/28/20 < 8 < 6 < 14 < 6 < 14 < 9 < 15 < 8 < 8 < 38 < 11 05/28/20 - 06/30/20 < 5 < 5 < 10 < 5 < 12 < 6 < 8 < 5 < 6 < 25 < 7 06/30/20 - 07/30/20 < 6 < 6 < 15 < 7 < 15 < 8 < 11 < 7 < 7 < 29 < 7 07/30/20 - 09/02/20 < 8 < 9 < 15 < 8 < 16 < 8 < 10 < 8 < 8 < 32 < 10 09/02/20 - 10/01/20 < 8 < 8 < 13 < 7 < 16 < 7 < 13 < 7 < 7 < 30 < 13 10/01/20 - 10/29/20 < 6 < 7 < 13 < 6 < 10 < 6 < 9 < 7 < 6 < 26 < 7 10/29/20 - 12/03/20 < 6 < 7 < 9 < 10 < 14 < 5 < 9 < 8 < 5 < 30 < 11 12/03/20 - 12/29/20 < 7 < 7 < 7 < 10 < 9 < 8 < 13 < 9 < 7 < 30 < 12 C-2 MEAN - - - - - - - - - - -

Q9-1 01/02/20 - 01/30/20 < 9 < 9 < 17 < 5 < 10 < 6 < 16 < 9 < 8 < 35 < 12 01/30/20 - 02/27/20 < 7 < 6 < 13 < 6 < 13 < 6 < 13 < 8 < 7 < 34 < 9 02/27/20 - 04/01/20 < 6 < 5 < 12 < 8 < 12 < 7 < 10 < 6 < 7 < 22 < 11 04/01/20 - 04/29/20 < 6 < 8 < 13 < 8 < 15 < 7 < 11 < 7 < 7 < 29 < 10 04/29/20 - 05/28/20 < 4 < 7 < 17 < 8 < 12 < 8 < 14 < 6 < 6 < 34 < 12 05/28/20 - 06/30/20 < 6 < 5 < 11 < 5 < 11 < 5 < 8 < 7 < 6 < 27 < 10 06/30/20 - 07/30/20 < 6 < 4 < 13 < 7 < 10 < 7 < 9 < 6 < 7 < 24 < 7 07/30/20 - 09/02/20 < 7 < 8 < 19 < 8 < 19 < 9 < 14 < 8 < 7 < 37 < 14 09/02/20 - 10/01/20 < 8 < 3 < 10 < 6 < 16 < 8 < 10 < 5 < 6 < 29 < 9 10/01/20 - 10/29/20 < 7 < 7 < 12 < 4 < 10 < 7 < 8 < 7 < 7 < 27 < 10 10/29/20 - 12/03/20 < 7 < 8 < 13 < 7 < 12 < 9 < 11 < 8 < 7 < 32 < 11 12/03/20 - 12/29/20 < 5 < 7 < 12 < 6 < 11 < 5 < 11 < 6 < 5 < 25 < 5 MEAN - - - - - - - - - - -

Table C-II.1 CONCENTRATIONS OF GROSS BETA IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD G15-2 G15-3 Q9-1 01/02/20 - 01/30/20 2.0 +/- 1.3 < 1.7 3.7 +/- 1.4 01/30/20 - 02/27/20 < 1.8 < 1.7 1.9 +/- 1.2 02/27/20 - 04/01/20 3.5 +/- 1.6 2.7 +/- 1.5 < 2.0 04/01/20 - 04/29/20 < 2.0 < 2.0 < 1.9 04/29/20 - 05/28/20 2.4 +/- 1.5 < 2.0 < 2.0 05/28/20 - 06/30/20 2.9 +/- 1.5 3.1 +/- 1.5 < 2.0 06/30/20 - 07/30/20 3.3 +/- 1.4 3.4 +/- 1.5 3.4 +/- 1.5 07/30/20 - 09/02/20 2.8 +/- 1.5 3.0 +/- 1.5 3.5 +/- 1.6 09/02/20 - 10/01/20 5.3 +/- 1.7 3.7 +/- 1.6 4.1 +/- 1.7 10/01/20 - 10/29/20 2.4 +/- 1.4 < 2.0 < 2.0 10/29/20 - 12/03/20 2.8 +/- 1.6 < 2.1 < 2.1 12/03/20 - 12/29/20 3.1 +/- 1.7 < 2.2 < 2.2 MEAN +/- 2 STD DEV 3.0 +/- 1.8 3.2 +/- 0.7 3.3 +/- 1.7 Table C-II.2 CONCENTRATIONS OF I-131 IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD G15-2 G15-3 Q9-1 01/02/20 - 01/30/20 < 0.8 < 0.7 < 0.8 01/30/20 - 02/27/20 < 0.5 < 0.8 < 0.6 02/27/20 - 04/01/20 < 0.7 < 0.6 < 0.6 04/01/20 - 04/29/20 < 0.8 < 0.7 < 0.8 04/29/20 - 05/28/20 < 0.7 < 0.7 < 0.7 05/28/20 - 06/30/20 < 0.7 < 0.8 < 0.7 06/30/20 - 07/30/20 < 0.9 < 0.6 < 0.8 07/30/20 - 09/02/20 < 0.7 < 0.8 < 0.8 09/02/20 - 10/01/20 < 0.8 < 0.8 < 0.9 10/01/20 - 10/29/20 < 0.9 < 0.9 < 0.8 10/29/20 - 12/03/20 < 0.9 < 0.9 < 0.9 12/03/20 - 12/29/20 < 0.8 < 0.8 < 0.8 MEAN - - -

Table C-II.3 CONCENTRATIONS OF TRITIUM IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD G15-2 G15-3 Q9-1 01/02/20 - 01/30/20 < 174 < 170 < 172 01/30/20 - 02/27/20 < 190 < 184 < 181 02/27/20 - 04/01/20 < 191 < 189 < 192 04/01/20 - 04/29/20 < 165 < 165 < 162 04/29/20 - 05/28/20 < 182 < 181 < 179 05/28/20 - 06/30/20 < 178 < 181 < 178 06/30/20 - 07/30/20 < 181 < 185 < 183 07/30/20 - 09/02/20 < 169 < 179 < 175 09/02/20 - 10/01/20 < 170 < 175 < 179 10/01/20 - 10/29/20 < 184 < 187 < 191 10/29/20 - 12/03/20 < 182 < 181 < 175 12/03/20 - 12/29/20 < 187 < 188 < 180 MEAN +/- 2 STD DEV - - -

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 COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR 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 G15-2 01/02/20 - 01/30/20 < 5 < 6 < 15 < 8 < 10 < 7 < 11 < 6 < 7 < 25 < 9 01/30/20 - 02/27/20 < 5 < 5 < 11 < 6 < 10 < 6 < 8 < 6 < 5 < 24 < 6 02/27/20 - 04/01/20 < 6 < 5 < 11 < 5 < 10 < 6 < 10 < 7 < 5 < 27 < 9 04/01/20 - 04/29/20 < 9 < 6 < 13 < 8 < 13 < 7 < 11 < 9 < 8 < 33 < 8 04/29/20 - 05/28/20 < 7 < 7 < 13 < 10 < 16 < 7 < 13 < 8 < 7 < 37 < 9 05/28/20 - 06/30/20 < 6 < 6 < 9 < 6 < 12 < 7 < 11 < 7 < 6 < 26 < 7 06/30/20 - 07/30/20 < 7 < 7 < 15 < 8 < 15 < 7 < 11 < 10 < 8 < 26 < 11 07/30/20 - 09/02/20 < 4 < 5 < 13 < 6 < 11 < 6 < 10 < 8 < 5 < 22 < 5 09/02/20 - 10/01/20 < 8 < 7 < 15 < 6 < 10 < 6 < 14 < 7 < 8 < 33 < 10 10/01/20 - 10/29/20 < 6 < 6 < 16 < 7 < 13 < 6 < 11 < 8 < 7 < 28 < 10 10/29/20 - 12/03/20 < 6 < 7 < 13 < 9 < 9 < 4 < 14 < 7 < 7 < 31 < 5 12/03/20 - 12/29/20 < 6 < 6 < 14 < 7 < 14 < 7 < 13 < 5 < 7 < 30 < 13 MEAN - - - - - - - - - - -

G15-3 01/02/20 - 01/30/20 < 8 < 8 < 17 < 6 < 15 < 9 < 13 < 9 < 7 < 34 < 12 01/30/20 - 02/27/20 < 6 < 5 < 12 < 6 < 12 < 8 < 10 < 4 < 6 < 21 < 9 02/27/20 - 04/01/20 < 6 < 6 < 15 < 6 < 11 < 6 < 9 < 5 < 7 < 29 < 9 C-4 04/01/20 - 04/29/20 < 6 < 7 < 14 < 8 < 17 < 7 < 15 < 6 < 8 < 34 < 12 04/29/20 - 05/28/20 < 7 < 7 < 13 < 7 < 13 < 7 < 9 < 7 < 7 < 34 < 12 05/28/20 - 06/30/20 < 4 < 4 < 10 < 4 < 7 < 5 < 7 < 5 < 5 < 18 < 9 06/30/20 - 07/30/20 < 6 < 7 < 16 < 9 < 15 < 7 < 12 < 6 < 7 < 32 < 9 07/30/20 - 09/02/20 < 6 < 7 < 12 < 6 < 14 < 7 < 12 < 8 < 6 < 30 < 6 09/02/20 - 10/01/20 < 6 < 8 < 15 < 7 < 15 < 8 < 12 < 7 < 7 < 30 < 10 10/01/20 - 10/29/20 < 4 < 4 < 13 < 6 < 11 < 7 < 6 < 8 < 8 < 24 < 9 10/29/20 - 12/03/20 < 7 < 7 < 13 < 6 < 10 < 9 < 10 < 7 < 7 < 30 < 11 12/03/20 - 12/29/20 < 6 < 8 < 14 < 5 < 13 < 8 < 14 < 9 < 7 < 27 < 13 MEAN - - - - - - - - - - -

Q9-1 01/02/20 - 01/30/20 < 5 < 6 < 14 < 7 < 12 < 6 < 12 < 8 < 7 < 31 < 9 01/30/20 - 02/27/20 < 5 < 4 < 12 < 5 < 11 < 5 < 9 < 6 < 6 < 28 < 7 02/27/20 - 04/01/20 < 6 < 7 < 12 < 6 < 12 < 6 < 13 < 7 < 6 < 32 < 10 04/01/20 - 04/29/20 < 7 < 7 < 10 < 5 < 12 < 5 < 8 < 8 < 5 < 28 < 8 04/29/20 - 05/28/20 < 7 < 7 < 14 < 7 < 12 < 8 < 12 < 8 < 7 < 32 < 8 05/28/20 - 06/30/20 < 4 < 5 < 10 < 6 < 10 < 5 < 8 < 6 < 6 < 24 < 8 06/30/20 - 07/30/20 < 7 < 8 < 11 < 7 < 13 < 6 < 8 < 8 < 7 < 27 < 9 07/30/20 - 09/02/20 < 6 < 7 < 13 < 7 < 9 < 5 < 10 < 7 < 6 < 28 < 11 09/02/20 - 10/01/20 < 7 < 6 < 14 < 8 < 11 < 8 < 12 < 7 < 6 < 27 < 12 10/01/20 - 10/29/20 < 5 < 5 < 9 < 5 < 9 < 5 < 10 < 7 < 6 < 28 < 5 10/29/20 - 12/03/20 < 5 < 5 < 11 < 4 < 13 < 6 < 8 < 6 < 5 < 24 < 5 12/03/20 - 12/29/20 < 6 < 7 < 16 < 6 < 11 < 7 < 11 < 9 < 8 < 30 < 12 MEAN - - - - - - - - - - -

Table C-III.1 CONCENTRATIONS OF GROSS BETA, IODINE-131, TRITIUM, AND STRONTIUM IN EFFLUENT WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD GR-B I-131 H-3 SR-89 SR-90 K1-1 01/02/20 - 01/30/20 < 1.8 < 0.9 < 172 01/30/20 - 02/27/20 < 1.7 < 0.7 < 185 02/27/20 - 04/01/20 < 2.0 < 0.7 15200 +/- 1580 04/01/20 - 04/29/20 < 1.8 < 0.9 20000 +/- 2040 04/29/20 - 05/28/20 2.5 +/- 1.3 < 0.7 20000 +/- 2050 05/28/20 - 06/30/20 2.6 +/- 1.4 < 0.8 19300 +/- 1980 01/02/20 - 06/30/20 < 3.4 < 0.9 06/30/20 - 07/30/20 3.2 +/- 1.5 < 0.8 9070 +/- 964 07/30/20 - 09/02/20 2.7 +/- 1.5 < 0.7 7760 +/- 828 09/02/20 - 10/01/20 3.6 +/- 1.6 < 0.8 5480 +/- 600 10/01/20 - 10/29/20 2.5 +/- 1.5 < 0.8 9330 +/- 994 10/29/20 - 12/03/20 3.5 +/- 1.5 < 0.9 4030 +/- 462 12/03/20 - 12/29/20 < 2.3 < 0.9 4370 +/- 495 06/30/20 - 12/29/20 < 4.7 < 0.9 MEAN +/- 2 STD DEV 2.9 +/- 1.0 - 11454 +/- 13106 - -

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

Table C-III.2 CONCENTRATIONS OF GAMMA EMITTERS IN EFFLUENT WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR 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 K1-1 01/02/20 - 01/30/20 < 8 < 8 < 14 < 9 < 14 < 8 < 13 < 8 < 8 < 38 < 10 01/30/20 - 02/27/20 < 6 < 7 < 15 < 7 < 11 < 7 < 14 < 7 < 7 < 31 < 10 02/27/20 - 04/01/20 < 7 < 7 < 12 < 7 < 16 < 7 < 12 < 7 < 8 < 33 < 13 04/01/20 - 04/29/20 < 7 < 7 < 16 < 7 < 11 < 6 < 13 < 6 < 6 < 38 < 7 04/29/20 - 05/28/20 < 7 < 7 < 16 < 6 < 15 < 9 < 13 < 7 < 7 < 38 < 9 05/28/20 - 06/30/20 < 5 < 5 < 11 < 5 < 11 < 6 < 7 < 5 < 6 < 23 < 9 06/30/20 - 07/30/20 < 6 < 6 < 11 < 8 < 13 < 5 < 14 < 7 < 6 < 32 < 11 07/30/20 - 09/02/20 < 7 < 8 < 12 < 10 < 13 < 8 < 12 < 7 < 8 < 29 < 8 09/02/20 - 10/01/20 < 7 < 7 < 14 < 6 < 14 < 8 < 10 < 7 < 7 < 30 < 12 10/01/20 - 10/29/20 < 7 < 7 < 14 < 6 < 10 < 6 < 12 < 8 < 7 < 31 < 10 10/29/20 - 12/03/20 < 5 < 5 < 12 < 7 < 10 < 6 < 9 < 6 < 6 < 23 < 7 C-6 12/03/20 - 12/29/20 < 6 < 7 < 13 < 7 < 10 < 7 < 11 < 8 < 7 < 35 < 10 MEAN - - - - - - - - - - -

Table C-IV.1 CONCENTRATIONS OF STRONTIUM IN PREDATOR AND BOTTOM FEEDER (FISH) SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION SITE PERIOD Sr-90 BKGB BOTTOM FEEDER 06/11/20 < 4.5 11/05/20 < 4.5 MEAN -

BKGP PREDATOR 06/11/20 < 4.4 11/05/20 < 4.5 MEAN -

INDB BOTTOM FEEDER 05/20/20 < 4.6 11/04/20 < 4.7 MEAN -

INDP PREDATOR 06/05/20 < 4.2 10/15/20 < 3.9 MEAN -

C-7

Table C-IV.2 CONCENTRATIONS OF GAMMA EMITTERS IN PREDATOR AND BOTTOM FEEDER (FISH) SAMPLES COLLECTED IN THE VICINTY OF THREE MILE ISLAND NUCLEAR 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 Cs-134 Cs-137 BKGB BOTTOM FEEDER 06/11/20 2874 +/- 897 < 52 < 54 < 102 < 51 < 101 < 61 < 58 11/05/20 2671 +/- 999 < 62 < 58 < 123 < 58 < 149 < 70 < 73 MEAN +/- 2 STD DEV 2773 + 287 - - - - - - -

BKGP PREDATOR 06/11/20 3456 +/- 784 < 41 < 40 < 78 < 43 < 70 < 50 < 39 11/05/20 3657 +/- 1079 < 65 < 70 < 142 < 57 < 138 < 61 < 69 MEAN +/- 2 STD DEV 3557 + 284 - - - - - - -

INDB BOTTOM FEEDER 05/20/20 2538 +/- 913 < 69 < 71 < 135 < 64 < 162 < 73 < 58 11/04/20 2933 +/- 1023 < 56 < 61 < 108 < 80 < 111 < 57 < 67 MEAN +/- 2 STD DEV 2736 + 559 - - - - - - -

INDP PREDATOR 06/05/20 4277 +/- 1097 < 58 < 48 < 132 < 48 < 105 < 62 < 61 10/15/20 2948 +/- 939 < 60 < 57 < 115 < 68 < 116 < 51 < 55 MEAN +/- 2 STD DEV 3613 +/- 1879 - - - - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-8

Table C-V.1 CONCENTRATIONS OF GAMMA EMITTERS IN SEDIMENT SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/KG DRY +/- 2 SIGMA COLLECTION SITE PERIOD K-40 Mn-54 Co-58 Co-60 Cs-134 Cs-137 A1-3 06/05/20 8069 +/- 1482 < 72 < 65 < 87 < 97 < 85 12/01/20 6795 +/- 1208 < 56 < 47 < 63 < 75 < 75 MEAN +/- 2 STD DEV 7432 +/- 1802 - - - - -

J2-1 06/05/20 12280 +/- 1754 < 79 < 71 < 70 < 106 < 89 12/01/20 11000 +/- 1412 < 78 < 60 < 71 < 90 < 87 MEAN +/- 2 STD DEV 11640 + 1810 - - - - -

K1-3 06/05/20 8732 +/- 1565 < 91 < 93 < 117 < 117 < 107 12/01/20 7858 +/- 1342 < 65 < 69 < 85 < 81 < 81 MEAN +/- 2 STD DEV 8295 +/- 1236 - - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-9

Table C-VI.1 CONCENTRATIONS OF GROSS BETA IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III PERIOD E1-2 F1-3 A3-1 G2-1 H3-1 M2-1 Q15-1 01/02/20 - 01/09/20 12 +/- 4 13 +/- 4 10 +/- 3 12 +/- 4 14 +/- 4 13 +/- 4 15 +/- 4 01/09/20 - 01/16/20 10 +/- 4 10 +/- 4 12 +/- 4 10 +/- 4 8 +/- 4 8 +/- 4 13 +/- 4 01/16/20 - 01/23/20 17 +/- 4 18 +/- 4 18 +/- 4 16 +/- 4 18 +/- 4 22 +/- 5 19 +/- 5 01/23/20 - 01/30/20 9 +/- 4 10 +/- 4 8 +/- 3 7 +/- 4 9 +/- 4 13 +/- 4 8 +/- 4 01/30/20 - 02/06/20 13 +/- 4 12 +/- 4 13 +/- 4 13 +/- 4 14 +/- 4 15 +/- 4 17 +/- 4 02/06/20 - 02/13/20 7 +/- 4 7 +/- 4 9 +/- 4 7 +/- 4 10 +/- 4 9 +/- 4 9 +/- 4 02/13/20 - 02/20/20 13 +/- 4 16 +/- 4 15 +/- 4 14 +/- 4 14 +/- 4 14 +/- 4 12 +/- 4 02/20/20 - 02/27/20 13 +/- 4 15 +/- 4 15 +/- 4 20 +/- 5 15 +/- 4 14 +/- 4 16 +/- 4 02/27/20 - 03/05/20 11 +/- 4 11 +/- 4 11 +/- 4 11 +/- 4 11 +/- 4 7 +/- 4 11 +/- 4 03/05/20 - 03/11/20 12 +/- 5 11 +/- 5 10 +/- 4 11 +/- 5 13 +/- 5 10 +/- 4 13 +/- 5 03/11/20 - 03/19/20 12 +/- 4 12 +/- 4 12 +/- 3 8 +/- 3 14 +/- 4 11 +/- 3 11 +/- 4 03/19/20 - 03/26/20 9 +/- 3 8 +/- 3 7 +/- 3 8 +/- 3 8 +/- 3 11 +/- 4 9 +/- 4 03/26/20 - 04/01/20 6 +/- 3 < 5 9 +/- 4 5 +/- 3 < 5 6 +/- 3 6 +/- 4 04/01/20 - 04/09/20 11 +/- 3 11 +/- 4 11 +/- 3 10 +/- 3 12 +/- 4 10 +/- 3 15 +/- 4 04/09/20 - 04/16/20 11 +/- 4 11 +/- 4 15 +/- 4 9 +/- 3 13 +/- 4 11 +/- 4 15 +/- 4 04/16/20 - 04/23/20 14 +/- 4 13 +/- 4 12 +/- 4 12 +/- 4 13 +/- 4 11 +/- 4 16 +/- 4 04/23/20 - 04/29/20 10 +/- 5 11 +/- 5 6 +/- 4 7 +/- 4 8 +/- 4 11 +/- 5 10 +/- 5 04/29/20 - 05/07/20 10 +/- 3 9 +/- 3 8 +/- 3 9 +/- 3 9 +/- 3 10 +/- 3 10 +/- 3 05/07/20 - 05/14/20 14 +/- 4 11 +/- 4 9 +/- 3 14 +/- 4 13 +/- 4 14 +/- 4 12 +/- 4 05/14/20 - 05/21/20 16 +/- 4 13 +/- 4 15 +/- 4 14 +/- 4 14 +/- 4 16 +/- 4 17 +/- 4 05/21/20 - 05/28/20 9 +/- 4 7 +/- 4 7 +/- 3 10 +/- 4 8 +/- 4 7 +/- 4 11 +/- 4 05/28/20 - 06/04/20 9 +/- 4 8 +/- 3 9 +/- 3 13 +/- 4 12 +/- 4 10 +/- 4 14 +/- 4 06/04/20 - 06/11/20 13 +/- 4 15 +/- 4 12 +/- 4 14 +/- 4 14 +/- 4 11 +/- 4 9 +/- 4 06/11/20 - 06/18/20 12 +/- 4 9 +/- 3 10 +/- 3 10 +/- 3 11 +/- 4 10 +/- 4 13 +/- 4 06/18/20 - 06/24/20 10 +/- 5 7 +/- 4 9 +/- 4 7 +/- 4 8 +/- 5 8 +/- 5 9 +/- 5 06/24/20 - 06/30/20 15 +/- 5 20 +/- 5 17 +/- 5 14 +/- 5 18 +/- 5 16 +/- 5 12 +/- 4 06/30/20 - 07/08/20 17 +/- 4 17 +/- 4 14 +/- 3 20 +/- 4 15 +/- 4 18 +/- 4 19 +/- 4 07/08/20 - 07/16/20 9 +/- 3 9 +/- 3 10 +/- 3 10 +/- 3 13 +/- 4 14 +/- 4 12 +/- 4 07/16/20 - 07/23/20 16 +/- 4 16 +/- 4 21 +/- 4 20 +/- 4 20 +/- 4 15 +/- 4 23 +/- 5 07/23/20 - 07/30/20 19 +/- 4 17 +/- 4 17 +/- 4 18 +/- 4 17 +/- 4 18 +/- 4 19 +/- 4 07/30/20 - 08/05/20 21 +/- 5 18 +/- 5 18 +/- 5 19 +/- 5 19 +/- 5 19 +/- 5 16 +/- 5 08/05/20 - 08/13/20 18 +/- 4 15 +/- 4 18 +/- 4 16 +/- 4 15 +/- 4 19 +/- 4 21 +/- 4 08/13/20 - 08/20/20 18 +/- 4 20 +/- 4 16 +/- 4 20 +/- 4 17 +/- 4 16 +/- 4 19 +/- 4 08/20/20 - 08/27/20 19 +/- 5 22 +/- 5 21 +/- 4 19 +/- 5 19 +/- 5 19 +/- 4 21 +/- 5 08/27/20 - 09/02/20 9 +/- 4 13 +/- 4 9 +/- 4 8 +/- 4 10 +/- 4 5 +/- 4 12 +/- 4 09/02/20 - 09/10/20 14 +/- 4 10 +/- 3 10 +/- 3 10 +/- 3 13 +/- 4 14 +/- 4 13 +/- 4 09/10/20 - 09/17/20 13 +/- 4 12 +/- 4 9 +/- 3 14 +/- 4 13 +/- 4 7 +/- 4 15 +/- 4 09/17/20 - 09/24/20 19 +/- 5 24 +/- 5 21 +/- 4 24 +/- 5 22 +/- 5 21 +/- 5 23 +/- 5 09/24/20 - 10/01/20 22 +/- 5 19 +/- 5 21 +/- 5 17 +/- 5 19 +/- 5 22 +/- 5 23 +/- 5 10/01/20 - 10/08/20 13 +/- 4 13 +/- 4 13 +/- 4 13 +/- 4 15 +/- 4 12 +/- 4 19 +/- 4 10/08/20 - 10/15/20 17 +/- 4 12 +/- 4 13 +/- 4 15 +/- 4 19 +/- 5 17 +/- 4 12 +/- 4 10/15/20 - 10/22/20 13 +/- 4 14 +/- 4 17 +/- 4 18 +/- 4 16 +/- 4 18 +/- 4 19 +/- 5 10/22/20 - 10/29/20 7 +/- 4 8 +/- 4 6 +/- 4 8 +/- 4 8 +/- 4 8 +/- 4 22 +/- 4 10/29/20 - 11/06/20 17 +/- 4 14 +/- 4 13 +/- 4 19 +/- 4 15 +/- 4 18 +/- 4 21 +/- 5 11/06/20 - 11/12/20 28 +/- 6 25 +/- 5 27 +/- 5 27 +/- 6 29 +/- 6 26 +/- 6 28 +/- 6 11/12/20 - 11/19/20 14 +/- 4 10 +/- 3 13 +/- 3 14 +/- 4 9 +/- 3 9 +/- 3 13 +/- 4 11/19/20 - 11/25/20 9 +/- 4 9 +/- 4 11 +/- 4 11 +/- 4 11 +/- 4 11 +/- 4 12 +/- 4 11/25/20 - 12/03/20 15 +/- 4 16 +/- 4 16 +/- 4 18 +/- 4 15 +/- 4 18 +/- 4 19 +/- 4 12/03/20 - 12/09/20 11 +/- 5 8 +/- 4 6 +/- 4 7 +/- 4 14 +/- 5 8 +/- 5 9 +/- 5 12/09/20 - 12/16/20 23 +/- 5 19 +/- 4 23 +/- 4 22 +/- 4 20 +/- 4 21 +/- 4 23 +/- 5 12/16/20 - 12/23/20 13 +/- 4 13 +/- 4 11 +/- 4 15 +/- 4 15 +/- 4 13 +/- 4 14 +/- 4 12/23/20 - 12/29/20 14 +/- 4 12 +/- 4 13 +/- 4 14 +/- 4 15 +/- 4 13 +/- 4 13 +/- 4 MEAN +/- 2 STD DEV 14 +/- 9 13 +/- 9 13 +/- 10 13 +/- 10 14 +/- 8 13 +/- 10 15 +/- 10 THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-10

Table C-VI.2 MONTHLY AND YEARLY MEAN VALUES OF GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA GROUP I - CLOSEST TO THE SITE BOUNDARY GROUP II - INTERMEDIATE OFFSITE GROUP III - CONTROL LOCATIONS COLLECTION MEAN COLLECTION MEAN COLLECTION MEAN PERIOD MIN MAX +/- 2SD PERIOD MIN MAX +/- 2SD PERIOD MIN MAX +/- 2SD 01/02/20 - 01/30/20 9 18 12 +/- 7 01/02/20 - 01/30/20 7 22 12 +/- 9 01/02/20 - 01/30/20 8 19 14 +/- 9 01/30/20 - 02/27/20 7 16 12 +/- 7 01/30/20 - 02/27/20 7 20 13 +/- 6 01/30/20 - 02/27/20 9 17 13 +/- 7 02/27/20 - 04/01/20 6 12 10 +/- 4 02/27/20 - 04/01/20 5 14 10 +/- 5 02/27/20 - 04/01/20 6 13 10 +/- 5 04/01/20 - 04/29/20 10 14 12 +/- 3 04/01/20 - 04/29/20 6 15 11 +/- 5 04/01/20 - 04/29/20 10 16 14 +/- 5 04/29/20 - 06/04/20 7 16 11 +/- 6 04/29/20 - 06/04/20 7 16 11 +/- 6 04/29/20 - 06/04/20 10 17 13 +/- 6 06/04/20 - 06/30/20 7 20 13 +/- 8 06/04/20 - 06/30/20 7 18 12 +/- 7 06/04/20 - 06/30/20 9 13 11 +/- 4 06/30/20 - 07/30/20 9 19 15 +/- 7 06/30/20 - 07/30/20 10 21 16 +/- 7 06/30/20 - 07/30/20 12 23 18 +/- 9 07/30/20 - 09/02/20 9 22 17 +/- 8 07/30/20 - 09/02/20 5 21 16 +/- 9 07/30/20 - 09/02/20 12 21 18 +/- 8 09/02/20 - 10/01/20 10 24 17 +/- 10 09/02/20 - 10/01/20 7 24 16 +/- 11 09/02/20 - 10/01/20 13 23 18 +/- 11 10/01/20 - 10/29/20 7 17 12 +/- 7 10/01/20 - 10/29/20 6 19 13 +/- 8 10/01/20 - 10/29/20 12 22 18 +/- 8 C-11 10/29/20 - 12/03/20 9 28 16 +/- 12 10/29/20 - 12/03/20 9 29 16 +/- 13 10/29/20 - 12/03/20 12 28 19 +/- 13 12/03/20 - 12/29/20 8 23 14 +/- 10 12/03/20 - 12/29/20 6 23 14 +/- 10 12/03/20 - 12/29/20 9 23 15 +/- 12 01/02/20 - 12/29/20 6 28 13 +/- 9 01/02/20 - 12/29/20 5 29 13 +/- 9 01/02/20 - 12/29/20 6 28 15 +/- 10

Table C-VI.3 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION SITE PERIOD Be-7 Mn-54 Co-58 Co-60 Nb-95 Zr-95 Cs-134 Cs-137 A3-1 01/02/20 - 04/01/20 68 +/- 17 < 2 < 2 < 1 < 2 < 4 < 2 < 2 04/01/20 - 06/30/20 72 +/- 17 < 2 < 2 < 2 < 1 < 3 < 2 < 2 06/30/20 - 10/01/20 72 +/- 18 < 2 < 2 < 2 < 2 < 4 < 2 < 2 10/01/20 - 12/29/20 66 +/- 20 < 3 < 3 < 4 < 4 < 6 < 5 < 4 MEAN +/- 2 STD DEV 69 +/- 6 - - - - - - -

E1-2 01/02/20 - 04/01/20 77 +/- 17 < 2 < 2 < 2 < 2 < 3 < 2 < 2 04/01/20 - 06/30/20 62 +/- 19 < 2 < 3 < 3 < 2 < 3 < 2 < 2 06/30/20 - 10/01/20 68 +/- 21 < 2 < 2 < 2 < 2 < 4 < 2 < 2 10/01/20 - 12/29/20 67 +/- 18 < 2 < 2 < 2 < 2 < 3 < 3 < 2 MEAN +/- 2 STD DEV 68 +/- 12 - - - - - - -

F1-3 01/02/20 - 04/01/20 54 +/- 13 < 2 < 2 < 2 < 2 < 3 < 2 < 2 04/01/20 - 06/30/20 83 +/- 20 < 3 < 2 < 4 < 2 < 4 < 3 < 2 06/30/20 - 10/01/20 83 +/- 26 < 4 < 3 < 5 < 5 < 7 < 4 < 3 10/01/20 - 12/29/20 52 +/- 14 < 2 < 2 < 2 < 2 < 3 < 2 < 2 MEAN +/- 2 STD DEV 68 +/- 35 - - - - - - -

G2-1 01/02/20 - 04/01/20 50 +/- 20 < 2 < 3 < 3 < 3 < 4 < 2 < 2 04/01/20 - 06/30/20 76 +/- 19 < 2 < 2 < 2 < 2 < 3 < 2 < 2 06/30/20 - 10/01/20 69 +/- 19 < 2 < 2 < 2 < 3 < 4 < 2 < 2 10/01/20 - 12/29/20 38 +/- 23 < 3 < 3 < 2 < 3 < 5 < 3 < 3 MEAN +/- 2 STD DEV 59 +/- 34 - - - - - - -

H3-1 01/02/20 - 04/01/20 55 +/- 16 < 2 < 2 < 2 < 2 < 4 < 2 < 2 04/01/20 - 06/30/20 72 +/- 18 < 3 < 2 < 2 < 3 < 5 < 3 < 3 06/30/20 - 10/01/20 94 +/- 28 < 3 < 4 < 3 < 4 < 7 < 4 < 3 10/01/20 - 12/29/20 57 +/- 22 < 2 < 2 < 3 < 2 < 4 < 3 < 2 MEAN +/- 2 STD DEV 69 +/- 35 - - - - - - -

M2-1 01/02/20 - 04/01/20 59 +/- 17 < 2 < 2 < 3 < 2 < 2 < 2 < 2 04/01/20 - 06/30/20 81 +/- 24 < 2 < 2 < 1 < 2 < 4 < 2 < 2 06/30/20 - 10/01/20 75 +/- 20 < 2 < 2 < 3 < 2 < 4 < 2 < 2 10/01/20 - 12/29/20 67 +/- 18 < 2 < 1 < 4 < 1 < 3 < 2 < 2 MEAN +/- 2 STD DEV 70 +/- 19 - - - - - - -

Q15-1 01/02/20 - 04/01/20 58 +/- 21 < 4 < 4 < 4 < 4 < 7 < 4 < 4 04/01/20 - 06/30/20 77 +/- 19 < 2 < 2 < 3 < 2 < 3 < 2 < 2 06/30/20 - 10/01/20 80 +/- 18 < 2 < 2 < 2 < 2 < 4 < 2 < 2 10/01/20 - 12/29/20 56 +/- 18 < 3 < 3 < 4 < 3 < 4 < 3 < 2 MEAN +/- 2 STD DEV 68 +/- 25 - - - - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-12

Table C-VII.1 CONCENTRATIONS OF I-131 IN AIR IODINE SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III PERIOD E1-2 F1-3 A3-1 G2-1 H3-1 M2-1 Q15-1 01/02/20 - 01/09/20 < 22 < 22 < 11 < 27 < 26 < 27 < 28 01/09/20 - 01/16/20 < 23 < 24 < 17 < 42 < 42 < 42 < 43 01/16/20 - 01/23/20 < 30 < 31 < 19 < 20 < 20 < 20 < 10 01/23/20 - 01/30/20 < 25 < 36 < 21 < 54 < 54 < 51 < 53 01/30/20 - 02/06/20 < 22 < 23 < 32 < 21 < 22 < 23 < 36 02/06/20 - 02/13/20 < 43 < 45 < 13 < 28 < 27 < 27 < 28 02/13/20 - 02/20/20 < 23 < 18 < 14 < 33 < 32 < 32 < 33 02/20/20 - 02/27/20 < 52 < 54 < 29 < 27 < 32 < 30 < 31 02/27/20 - 03/05/20 < 19 < 17 < 26 < 35 < 33 < 34 < 35 03/05/20 - 03/11/20 < 45 < 19 < 26 < 31 < 29 < 29 < 30 03/11/20 - 03/19/20 < 30 < 31 < 16 < 41 < 41 < 41 < 42 03/19/20 - 03/26/20 < 32 < 33 < 17 < 37 < 37 < 37 < 38 03/26/20 - 04/01/20 < 19 < 24 < 11 < 24 < 23 < 23 < 12 04/01/20 - 04/09/20 < 30 < 26 < 20 < 31 < 31 < 31 < 24 04/09/20 - 04/16/20 < 25 < 26 < 17 < 42 < 42 < 42 < 44 04/16/20 - 04/23/20 < 32 < 28 < 34 < 33 < 33 < 33 < 31 04/23/20 - 04/29/20 < 35 < 36 < 56 < 60 < 59 < 59 < 26 04/29/20 - 05/07/20 < 29 < 17 < 32 < 29 < 29 < 29 < 35 05/07/20 - 05/14/20 < 18 < 31 < 48 < 31 < 30 < 31 < 22 05/14/20 - 05/21/20 < 16 < 33 < 21 < 33 < 33 < 34 < 23 05/21/20 - 05/28/20 < 23 < 22 < 15 < 28 < 28 < 28 < 29 05/28/20 - 06/04/20 < 19 < 15 < 17 < 45 < 45 < 45 < 46 06/04/20 - 06/11/20 < 17 < 40 < 28 < 40 < 40 < 40 < 30 06/11/20 - 06/18/20 < 23 < 18 < 36 < 39 < 38 < 39 < 33 06/18/20 - 06/24/20 < 21 < 47 < 42 < 48 < 48 < 49 < 20 06/24/20 - 06/30/20 < 16 < 28 < 40 < 28 < 27 < 28 < 44 06/30/20 - 07/08/20 < 14 < 24 < 40 < 24 < 23 < 24 < 44 07/08/20 - 07/16/20 < 17 < 41 < 24 < 41 < 41 < 41 < 27 07/16/20 - 07/23/20 < 27 < 27 < 16 < 33 < 33 < 34 < 34 07/23/20 - 07/30/20 < 31 < 30 < 35 < 16 < 38 < 38 < 38 07/30/20 - 08/05/20 < 18 < 37 < 38 < 37 < 37 < 35 < 41 08/05/20 - 08/13/20 < 37 < 36 < 30 < 32 < 31 < 32 < 15 08/13/20 - 08/20/20 < 17 < 39 < 29 < 39 < 38 < 39 < 32 08/20/20 - 08/27/20 < 20 < 46 < 21 < 47 < 46 < 43 < 22 08/27/20 - 09/02/20 < 49 < 49 < 37 < 40 < 39 < 42 < 18 09/02/20 - 09/10/20 < 16 < 37 < 16 < 37 < 37 < 37 < 16 09/10/20 - 09/17/20 < 51 < 50 < 19 < 20 < 20 < 21 < 21 09/17/20 - 09/24/20 < 19 < 23 < 23 < 59 < 59 < 59 < 60 09/24/20 - 10/01/20 < 13 < 30 < 26 < 30 < 30 < 30 < 29 10/01/20 - 10/08/20 < 45 < 44 < 26 < 33 < 33 < 33 < 34 10/08/20 - 10/15/20 < 11 < 24 < 54 < 24 < 24 < 24 < 25 10/15/20 - 10/22/20 < 41 < 40 < 22 < 57 < 58 < 57 < 58 10/22/20 - 10/29/20 < 23 < 53 < 18 < 53 < 53 < 53 < 50 10/29/20 - 11/06/20 < 19 < 23 < 9 < 22 < 22 < 22 < 22 11/06/20 - 11/12/20 < 20 < 20 < 15 < 36 < 36 < 36 < 37 11/12/20 - 11/19/20 < 18 < 34 < 17 < 45 < 45 < 45 < 46 11/19/20 - 11/25/20 < 21 < 33 < 24 < 26 < 26 < 26 < 27 11/25/20 - 12/03/20 < 24 < 28 < 18 < 28 < 28 < 28 < 20 12/03/20 - 12/09/20 < 38 < 38 < 40 < 44 < 44 < 45 < 19 12/09/20 - 12/16/20 < 27 < 27 < 13 < 31 < 30 < 31 < 31 12/16/20 - 12/23/20 < 26 < 25 < 18 < 25 < 25 < 25 < 16 12/23/20 - 12/29/20 < 22 < 25 < 28 < 30 < 30 < 30 < 30 MEAN - - - - - - -

C-13

TABLE C-VIII.1 CONCENTRATIONS OF I-131 IN MILK SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION CONTROL FARM INDICATOR FARMS PERIOD K15-3 F4-1 G2-1 P4-1 01/15/20 < 0.9 < 0.8 < 0.8 < 0.9 02/12/20 < 0.7 < 0.8 < 0.8 < 0.9 03/11/20 < 0.8 < 0.7 < 0.7 < 0.6 03/25/20 < 0.6 < 0.6 < 0.6 < 0.6 04/08/20 < 0.7 < 0.8 < 0.7 < 0.7 04/23/20 < 0.6 < 0.9 < 0.9 < 0.7 05/07/20 < 0.7 < 0.8 < 0.7 < 0.7 05/20/20 < 0.6 < 0.7 < 0.6 < 0.6 06/03/20 < 0.6 < 0.7 < 0.6 < 0.7 06/17/20 < 0.9 < 0.5 < 0.4 < 0.7 07/01/20 < 0.7 < 0.8 < 0.6 < 0.7 07/15/20 < 0.8 < 0.9 < 0.7 < 0.7 07/29/20 < 0.8 < 0.7 < 0.8 < 0.7 08/12/20 < 0.9 < 0.7 < 0.8 < 0.9 08/26/20 < 0.5 < 0.7 < 0.8 < 0.8 09/09/20 < 0.8 < 0.7 < 0.8 < 0.8 09/23/20 < 0.9 < 0.4 < 0.9 < 0.6 10/07/20 < 0.8 < 0.9 < 0.8 < 0.9 10/22/20 < 0.9 < 0.8 < 0.9 < 0.8 11/04/20 < 0.9 < 0.9 < 0.9 < 0.8 11/18/20 < 0.9 < 0.8 < 0.7 < 0.9 12/09/20 < 0.9 < 0.8 < 0.9 < 0.8 MEAN - - - -

C-14

Table C-VIII.2 CONCENTRATIONS OF STRONTIUM IN MILK SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA CONTROL FARM INDICATOR FARMS COLLECTION K15-3 F4-1 G2-1 P4-1 PERIOD Sr-89 Sr-90 Sr-89 Sr-90 Sr-89 Sr-90 Sr-89 Sr-90 01/15/20 - 03/25/20 < 3.8 < 0.9 < 3.3 < 0.5 < 4.6 < 0.9 < 3.7 < 0.8 04/08/20 - 06/17/20 < 3.9 < 0.9 < 4.2 < 0.7 < 3.4 < 0.9 < 4.6 < 0.9 07/01/20 - 09/23/20 < 3.5 < 0.8 < 4.5 < 0.7 < 4.2 < 1.0 < 3.4 < 0.8 10/07/20 - 12/09/20 < 4.0 < 0.8 < 4.8 < 0.7 < 4.5 < 0.7 < 4.3 < 0.7 MEAN +/- 2 STD DEV - - - - - - - -

C-15

Table C-VIII.3 CONCENTRATIONS OF GAMMA EMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD K-40 Cs-134 Cs-137 Ba-140 La-140 F4-1 01/15/20 1310 +/- 140 < 8 < 6 < 22 < 6 02/12/20 1198 +/- 138 < 5 < 6 < 20 < 6 03/11/20 1382 +/- 182 < 9 < 8 < 30 < 9 03/25/20 1329 +/- 179 < 9 < 9 < 31 < 9 04/08/20 1161 +/- 120 < 6 < 5 < 20 < 6 04/23/20 1337 +/- 183 < 8 < 7 < 31 < 9 05/06/20 1290 +/- 131 < 4 < 5 < 23 < 6 05/20/20 1194 +/- 156 < 9 < 9 < 39 < 10 06/03/20 1356 +/- 240 < 11 < 7 < 31 < 8 06/17/20 1152 +/- 150 < 10 < 8 < 33 < 14 07/01/20 1112 +/- 167 < 9 < 7 < 23 < 7 07/15/20 1418 +/- 158 < 8 < 6 < 29 < 9 07/29/20 1625 +/- 190 < 9 < 7 < 29 < 11 08/12/20 1354 +/- 217 < 11 < 7 < 34 < 9 08/26/20 1249 +/- 191 < 9 < 9 < 30 < 6 09/09/20 1241 +/- 184 < 8 < 7 < 34 < 7 09/23/20 1618 +/- 180 < 9 < 8 < 32 < 9 10/07/20 1272 +/- 168 < 9 < 8 < 26 < 11 10/22/20 1446 +/- 167 < 9 < 9 < 32 < 14 11/04/20 1182 +/- 171 < 10 < 8 < 37 < 14 11/18/20 1380 +/- 152 < 7 < 7 < 35 < 9 12/09/20 1293 +/- 177 < 8 < 9 < 31 < 9 MEAN +/- 2 STD DEV 1314 +/- 269 - - - -

G2-1 01/15/20 777 +/- 129 < 8 < 7 < 23 < 8 02/12/20 1214 +/- 119 < 6 < 6 < 24 < 6 03/11/20 1292 +/- 191 < 7 < 9 < 33 < 8 03/25/20 1176 +/- 206 < 8 < 7 < 30 < 14 04/08/20 1119 +/- 156 < 7 < 7 < 26 < 7 04/23/20 1260 +/- 177 < 8 < 8 < 35 < 9 05/06/20 1272 +/- 114 < 5 < 5 < 23 < 6 05/20/20 1196 +/- 174 < 9 < 7 < 37 < 12 06/03/20 1145 +/- 176 < 10 < 9 < 33 < 10 06/17/20 1179 +/- 201 < 10 < 9 < 36 < 7 07/01/20 1327 +/- 193 < 9 < 8 < 26 < 7 07/15/20 1069 +/- 162 < 7 < 8 < 36 < 11 07/29/20 1169 +/- 180 < 10 < 9 < 32 < 10 08/12/20 1063 +/- 165 < 6 < 6 < 27 < 7 08/26/20 1084 +/- 177 < 10 < 10 < 31 < 9 09/09/20 1356 +/- 220 < 8 < 5 < 33 < 14 09/23/20 1316 +/- 198 < 10 < 7 < 31 < 7 10/07/20 1172 +/- 144 < 8 < 7 < 26 < 6 10/22/20 1121 +/- 179 < 8 < 8 < 34 < 10 11/04/20 1045 +/- 172 < 9 < 9 < 42 < 9 11/18/20 1365 +/- 189 < 7 < 9 < 27 < 11 12/09/20 1166 +/- 178 < 9 < 8 < 31 < 10 MEAN +/- 2 STD DEV 1176 +/- 261 - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-16

Table C-VIII.3 CONCENTRATIONS OF GAMMA EMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD K-40 Cs-134 Cs-137 Ba-140 La-140 K15-3 01/15/20 984 +/- 161 < 8 < 6 < 25 < 7 02/12/20 1220 +/- 108 < 5 < 5 < 19 < 5 03/11/20 1206 +/- 176 < 9 < 8 < 35 < 8 03/25/20 1133 +/- 202 < 8 < 8 < 40 < 9 04/08/20 1082 +/- 141 < 6 < 6 < 20 < 5 04/23/20 922 +/- 168 < 6 < 7 < 32 < 13 05/06/20 1023 +/- 135 < 5 < 6 < 25 < 7 05/20/20 1040 +/- 136 < 8 < 7 < 33 < 8 06/03/20 1053 +/- 198 < 9 < 9 < 29 < 6 06/17/20 877 +/- 147 < 8 < 7 < 30 < 9 07/01/20 1044 +/- 136 < 8 < 7 < 24 < 7 07/15/20 961 +/- 136 < 7 < 7 < 27 < 7 07/29/20 1077 +/- 193 < 8 < 7 < 28 < 12 08/12/20 1173 +/- 159 < 8 < 7 < 30 < 10 08/26/20 934 +/- 159 < 8 < 8 < 26 < 9 09/09/20 1096 +/- 170 < 8 < 9 < 29 < 11 09/23/20 1131 +/- 194 < 7 < 9 < 36 < 13 10/07/20 852 +/- 137 < 8 < 7 < 25 < 6 10/22/20 1152 +/- 150 < 8 < 7 < 30 < 10 11/04/20 1188 +/- 188 < 9 < 11 < 37 < 13 11/18/20 1202 +/- 179 < 8 < 10 < 39 < 7 12/09/20 1152 +/- 177 < 8 < 8 < 30 < 5 MEAN +/- 2 STD DEV 1068 +/- 220 - - - -

P4-1 01/15/20 1346 +/- 177 < 8 < 7 < 22 < 5 02/12/20 1394 +/- 146 < 6 < 6 < 21 < 7 03/11/20 1426 +/- 165 < 8 < 8 < 36 < 12 03/25/20 1367 +/- 166 < 9 < 9 < 31 < 13 04/08/20 1559 +/- 142 < 5 < 5 < 18 < 7 04/23/20 1365 +/- 161 < 9 < 8 < 28 < 11 05/07/20 1436 +/- 184 < 9 < 10 < 39 < 12 05/20/20 1197 +/- 173 < 8 < 8 < 29 < 9 06/03/20 1141 +/- 162 < 10 < 9 < 33 < 11 06/17/20 1582 +/- 234 < 9 < 7 < 28 < 10 07/01/20 1272 +/- 178 < 9 < 7 < 23 < 8 07/15/20 1211 +/- 150 < 6 < 6 < 24 < 7 07/29/20 1388 +/- 198 < 11 < 8 < 36 < 13 08/12/20 1443 +/- 179 < 8 < 8 < 28 < 7 08/26/20 1287 +/- 178 < 7 < 8 < 34 < 9 09/09/20 1218 +/- 160 < 6 < 8 < 34 < 11 09/23/20 1466 +/- 170 < 7 < 7 < 28 < 8 10/07/20 1420 +/- 138 < 7 < 7 < 23 < 7 10/22/20 1423 +/- 156 < 7 < 7 < 23 < 9 11/04/20 1526 +/- 217 < 9 < 8 < 40 < 11 11/18/20 1369 +/- 198 < 8 < 8 < 34 < 10 12/09/20 1208 +/- 197 < 9 < 10 < 29 < 12 MEAN +/- 2 STD DEV 1366 +/- 242 - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-17

Table C-IX.1 CONCENTRATIONS OF STRONTIUM AND GAMMA EMITTERS IN FOOD PRODUCT SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION SITE PERIOD Sr-90 Be-7 K-40 I-131 Cs-134 Cs-137 B10-2 Kale Leaves 06/25/20 < 196 4238 +/- 562 < 29 < 26 < 25 Collard Leaves 06/25/20 < 225 3776 +/- 479 < 27 < 25 < 18 Bok Choy Leaves 06/25/20 < 226 3992 +/- 544 < 26 < 23 < 21 Cabbage Leaves 07/23/20 < 245 3182 +/- 551 < 28 < 29 < 27 Cauliflower Leaves 07/23/20 < 272 4766 +/- 610 < 35 < 34 < 24 Kale Leaves 07/23/20 < 267 5763 +/- 699 < 35 < 32 < 31 Tomato 07/23/20 < 3.8 < 255 1577 +/- 448 < 41 < 35 < 30 Sunflower Leaves 08/26/20 882 +/- 269 6623 +/- 865 < 32 < 44 < 35 Cucumber Leaves 08/26/20 820 +/- 284 4034 +/- 603 < 30 < 29 < 31 Kale Leaves 08/26/20 < 307 3864 +/- 767 < 36 < 47 < 33 Corn 08/26/20 < 4.6 < 160 1914 +/- 386 < 19 < 16 < 16 Potatoes 08/26/20 < 4.0 < 133 2337 +/- 364 < 20 < 23 < 16 Sunflower Leaves 09/24/20 928 +/- 458 7134 +/- 944 < 46 < 41 < 40 Collard Leaves 09/24/20 < 296 4292 +/- 783 < 45 < 44 < 34 Cabbage Leaves 09/24/20 < 296 3151 +/- 650 < 34 < 29 < 30 MEAN +/- 2 STD DEV - 876 +/- 109 4043 +/- 3160 - - -

E1-2 Cabbage Leaves 06/25/20 < 310 2688 +/- 566 < 19 < 28 < 33 Swiss Chard Leaves 06/25/20 710 +/- 253 8717 +/- 862 < 32 < 30 < 33 Brussels Sprout Leaves 06/25/20 < 279 2757 +/- 519 < 39 < 35 < 31 Brussels Sprout Leaves 07/23/20 496 +/- 218 3463 +/- 622 < 33 < 31 < 33 Cabbage Leaves 07/23/20 < 392 3717 +/- 583 < 37 < 32 < 35 Swiss Chard Leaves 07/23/20 545 +/- 290 6838 +/- 915 < 49 < 46 < 35 Tomato 07/23/20 < 3.3 < 167 1310 +/- 321 < 25 < 23 < 20 Swiss Chard Leaves 08/26/20 518 +/- 244 5630 +/- 731 < 25 < 24 < 25 Collard Leaves 08/26/20 < 315 3430 +/- 574 < 34 < 35 < 34 Kale Leaves 08/26/20 < 385 6168 +/- 869 < 41 < 40 < 39 Corn 08/26/20 < 4.4 < 192 2803 +/- 409 < 24 < 30 < 22 Potatoes 08/26/20 < 3.2 < 189 4425 +/- 717 < 36 < 33 < 30 Cabbage Leaves 09/23/20 < 384 3208 +/- 644 < 44 < 35 < 35 Collard Leaves 09/23/20 1004 +/- 264 3974 +/- 665 < 45 < 30 < 34 Swiss Chard Leaves 09/23/20 < 357 5806 +/- 796 < 45 < 39 < 31 MEAN +/- 2 STD DEV - 655 +/- 426 4329 +/- 3882 - - -

H1-2 Yellow Squash Leaves 06/25/20 < 341 4348 +/- 580 < 39 < 29 < 29 Cucumber Leaves 06/25/20 471 +/- 218 3098 +/- 529 < 41 < 30 < 31 Watermelon Leaves 06/25/20 < 344 3553 +/- 582 < 44 < 38 < 33 Yellow Squash Leaves 07/23/20 910 +/- 226 4045 +/- 669 < 41 < 33 < 29 Watermelon Leaves 07/23/20 1093 +/- 285 4271 +/- 583 < 29 < 34 < 24 Cucumber Leaves 07/23/20 722 +/- 260 3076 +/- 513 < 34 < 35 < 31 Yellow Squash Leaves 08/26/20 1468 +/- 350 2995 +/- 701 < 35 < 41 < 37 Cucumber Leaves 08/26/20 444 +/- 364 3288 +/- 596 < 30 < 37 < 24 Pumpkin Leaves 08/26/20 1527 +/- 369 3612 +/- 626 < 31 < 28 < 39 Pumpkin Leaves 09/23/20 < 360 1670 +/- 497 < 52 < 42 < 30 Yellow Squash Leaves 09/23/20 < 303 4833 +/- 775 < 46 < 36 < 36 Cucumber Leaves 09/23/20 < 287 3222 +/- 624 < 40 < 33 < 32 MEAN +/- 2 STD DEV 948 +/- 880 3501 +/- 1648 - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-18

Table C-X.1 QUARTERLY OSLD RESULTS FOR THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF MILLIREM/QUARTER STATION MEAN CODE +/- 2 S.D. JAN - MAR APR - JUN JUL - SEP OCT - DEC A1-4 15.0 +/- 2.2 13.7 14.8 15.1 16.4 A3-1 14.0 +/- 2.8 14.8 13.5 15.3 12.2 A5-1 18.5 +/- 2.6 18.7 16.9 18.4 20.1 A9-3 15.4 +/- 1.4 16.1 15.0 15.9 14.6 B1-1 16.5 +/- 3.2 14.4 15.9 17.8 17.7 B1-2 15.5 +/- 3.1 13.5 15.1 16.9 16.6 B2-1 15.4 +/- 2.5 16.6 16.2 14.7 13.9 B5-1 17.7 +/- 1.1 17.6 17.3 17.5 18.5 C1-1 17.8 +/- 3.5 18.5 17.1 19.8 15.8 C1-2 15.2 +/- 3.1 13.3 15.0 15.4 17.1 C2-1 17.0 +/- 2.9 18.0 16.0 18.4 15.5 C5-1 18.1 +/- 1.9 19.2 18.2 18.1 16.9 C8-1 18.5 +/- 2.1 18.5 19.1 19.3 17.0 D1-1 15.8 +/- 2.3 14.2 15.9 16.3 16.9 D1-2 16.4 +/- 2.4 16.5 16.9 17.4 14.7 D2-2 21.6 +/- 1.3 21.9 21.1 22.3 21.0 D6-1 20.0 +/- 2.4 20.7 18.8 21.3 19.2 E1-2 16.3 +/- 2.7 17.1 15.2 17.7 15.0 E1-4 16.3 +/- 2.5 14.7 16.8 17.6 16.0 E2-3 19.7 +/- 2.6 20.3 18.9 21.1 18.3 E5-1 20.0 +/- 2.2 21.3 19.4 20.5 18.9 E7-1 17.8 +/- 1.6 18.8 17.0 17.9 17.4 F1-1 17.0 +/- 2.2 17.8 16.9 17.7 15.4 F1-2 16.5 +/- 1.9 15.5 16.0 17.0 17.6 F1-4 15.3 +/- 4.0 12.4 15.4 16.4 16.9 F2-1 19.7 +/- 2.4 20.7 19.0 20.6 18.3 F5-1 20.2 +/- 2.4 21.2 19.4 21.3 19.0 G1-2 18.1 +/- 4.1 19.0 16.9 20.6 16.0 G1-3 15.4 +/- 2.7 13.5 16.1 15.5 16.6 G1-5 15.0 +/- 3.9 12.8 16.4 16.9 14.0 G1-6 15.8 +/- 2.1 14.4 16.0 15.7 16.9 G2-4 21.5 +/- 2.9 23.1 21.4 21.8 19.6 G5-1 17.0 +/- 2.9 17.5 16.8 18.6 15.1 H1-1 18.1 +/- 3.3 15.6 19.1 18.6 18.9 H3-1 13.8 +/- 2.2 15.4 13.8 12.9 13.2 H5-1 12.9 +/- 2.4 13.6 11.1 13.5 13.4 H8-1 28.3 +/- 3.9 27.8 27.4 31.1 26.7 J1-1 15.1 +/- 2.4 13.4 16.0 15.1 15.9 J1-3 13.8 +/- 1.9 12.8 13.5 13.6 15.1 J3-1 16.6 +/- 1.7 16.8 15.9 15.9 17.7 J5-1 19.1 +/- 2.1 19.2 17.6 19.3 20.1 J7-1 20.0 +/- 2.2 20.2 19.1 19.3 21.5 K1-4 15.7 +/- 3.3 13.3 16.9 16.1 16.6 K2-1 20.2 +/- 1.9 19.3 19.8 20.2 21.5 K3-1 14.4 +/- 2.0 15.0 12.9 14.6 15.0 K5-1 19.2 +/- 2.8 19.3 17.2 20.5 19.7 K8-1 16.9 +/- 1.8 17.8 16.1 16.2 17.6 C-19

Table C-X.1 QUARTERLY OSLD RESULTS FOR THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF MILLIREM/QUARTER STATION MEAN CODE +/- 2 S.D. JAN - MAR APR - JUN JUL - SEP OCT - DEC L1-1 16.7 +/- 3.3 14.7 16.2 18.6 17.2 L1-2 14.9 +/- 2.3 14.0 16.1 13.8 15.6 L2-1 16.4 +/- 2.2 15.7 15.3 17.2 17.5 L5-1 15.1 +/- 2.0 16.2 13.8 15.5 15.0 L8-1 16.2 +/- 1.0 16.1 15.5 16.6 16.4 M1-1 15.8 +/- 3.1 13.6 16.2 16.0 17.2 M1-2 18.3 +/- 2.2 17.7 19.6 17.1 18.8 M2-1 14.3 +/- 2.7 15.6 12.9 13.5 15.3 M5-1 16.5 +/- 1.3 17.0 15.7 17.1 16.3 M9-1 22.0 +/- 5.4 20.7 20.0 26.0 21.3 N1-1 17.2 +/- 3.8 15.1 19.7 16.9 17.2 N1-3 15.8 +/- 3.7 13.4 15.5 16.4 17.8 N2-1 17.5 +/- 1.0 18.1 16.9 17.5 17.4 N5-1 14.2 +/- 1.0 14.0 13.7 14.0 14.9 N8-1 18.8 +/- 1.7 18.8 17.8 19.9 18.6 P1-1 16.0 +/- 1.2 16.7 16.2 15.6 15.3 P1-2 16.5 +/- 4.6 14.7 15.3 16.0 19.8 P2-1 19.6 +/- 1.3 20.2 18.8 19.3 20.1 P5-1 16.4 +/- 1.7 15.7 15.7 17.4 16.7 P8-1 13.8 +/- 0.9 14.1 13.2 14.2 13.7 Q1-1 17.5 +/- 3.8 16.5 16.7 16.4 20.3 Q1-2 13.9 +/- 2.3 12.6 13.9 13.8 15.4 Q2-1 14.6 +/- 2.8 13.8 13.1 16.3 15.1 Q5-1 15.6 +/- 1.8 15.7 14.4 15.6 16.6 Q9-1 16.5 +/- 1.4 17.0 15.8 17.1 15.9 R1-1 14.8 +/- 2.4 13.3 14.5 15.0 16.2 R1-2 15.5 +/- 3.0 14.1 17.1 14.3 16.4 R3-1 20.7 +/- 2.7 21.1 19.7 22.4 19.5 R5-1 18.2 +/- 0.5 18.5 18.3 17.9 18.1 R9-1 18.6 +/- 2.0 19.2 17.4 19.6 18.0 B10-1 18.2 +/- 3.1 19.3 17.2 19.7 16.6 D15-1 17.9 +/- 1.1 18.0 17.6 18.6 17.3 F10-1 21.5 +/- 1.8 21.8 21.0 22.6 20.6 F25-1 18.4 +/- 1.8 19.4 18.4 18.7 17.2 G10-1 26.2 +/- 3.8 27.9 25.0 27.7 24.2 G15-1 23.2 +/- 2.4 23.5 24.0 23.9 21.4 H15-1 17.3 +/- 1.5 17.0 16.5 18.3 17.3 J15-1 20.4 +/- 3.0 20.6 18.3 20.9 21.8 K15-1 16.7 +/- 3.3 17.3 14.3 16.9 18.1 L15-1 17.0 +/- 1.6 16.3 16.3 17.6 17.8 N15-2 19.1 +/- 2.2 19.6 17.7 20.2 18.8 Q15-1 18.0 +/- 2.2 18.9 17.1 16.9 18.9 R15-1 16.5 +/- 3.3 17.6 16.5 17.8 14.2 C-20

TABLE C-X.2 MEAN QUARTERLY OSLD RESULTS FOR THE SITE BOUNDARY, INDICATOR AND CONTROL LOCATIONS FOR THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF MILLIREM/QUARTER

+/- 2 STANDARD DEVIATIONS OF THE STATION DATA COLLECTION SITE BOUNDARY PERIOD +/- 2 STD DEV INDICATOR CONTROL JAN-MAR 13.8 +/- 1.9 17.8 +/- 5.5 19.6 +/- 6.8 APR-JUN 15.7 +/- 2.5 17.0 +/- 5.3 18.3 +/- 6.5 JUL-SEP 16.2 +/- 2.7 18.1 +/- 6.4 19.8 +/- 6.7 OCT-DEC 16.8 +/- 2.6 17.3 +/- 5.1 18.8 +/- 5.5 TABLE C-X.3

SUMMARY

OF THE AMBIENT DOSIMETRY PROGRAM FOR THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF MILLIREMQUARTER SAMPLES PERIOD PERIOD PERIOD MEAN LOCATION ANALYZED MINIMUM MAXIMUM +/- 2 STD DEV SITE BOUNDARY 76 12.4 19.8 15.6 +/- 3.3 INDICATOR 240 11.1 31.1 17.6 +/- 5.6 CONTROL 44 14.2 27.9 19.1 +/- 6.3 SITE BOUNDARY STATIONS - A1-4, B1-2, C1-2, D1-1, E1-4, F1-2, F1-4, G1-3 G1-5, G1-6, H1-1, J1-3, K1-4, L1-1, M1-1, N1-3, P1-2, Q1-2, R1-1 INDICATOR STATIONS - A3-1, A5-1, A9-3, B1-1, B10-1, B2-1, B5-1, C1-1, C2-1, C5-1, C8-1, D1-2, D2-2, D6-1, E1-2, E2-3, E5-1, E7-1, F1-1, F10-1, F2-1, F5-1, G1-2, G2-4, G5-1, H3-1, H5-1, H8-1, J1-1, J3-1, J5-1, J7-1, K2-1, K3-1, K5-1, K8-1, L1-2, L2-1, L5-1, L8-1, M1-2, M2-1, M5-1, M9-1, N1-1, N2-1, N5-1, N8-1, P1-1, P2-1, P5-1, Q1-1, Q2-1, Q5-1, Q9-1, R1-2, R3-1, R5-1, R9-1 CONTROL STATIONS - D15-1, F25-1, G10-1, G15-1, H15-1, J15-1, K15-1, L15-1, N15-1, Q15-1, R15-1 C-21

FIGURE C-1 Monthly Tritium Concentrations in Surface Water and Effluent Water Three Mile Island Nuclear Station, 2020 Station J1-2 (Downstream of Discharge) Station Q9-1 (Control) 100000 Picocuries per Liter 10000 1000 100 10 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C-22 Month Station K1-1 (TMINS Liquid Discharge) 1000000 Picocuries per Liter 100000 10000 1000 100 10 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

FIGURE C-2 Mean Quarterly Tritium Concentrations in Surface Water Three Mile Island Nuclear Station, 1974 - 2020 Indicator Samples Control Samples 12000 Significant Events 11000 TMI-1 Critical June 1974 TMI-2 Critical March 1978 10000 TMI-2 Accident March 1979 TMI-2 RB Purge June 1980 9000 Chernobyl April 1986 Major Atm. Nuclear Weapon Tests 8000 June 1974 September 1974 September 1976 November 1976 7000 Picocuries per Liter September 1977 March 1978 C-23 6000 December 1978 October 1980 5000 4000 3000 2000 1000 0

-1000 1974 1983 1992 2001 2010 2019 Year

I Dec I

FIGURE C-3 I

Nov I

Oct I

Control Samples I

Three Mile Island Nuclear Station, 2020 Sep I

Aug I

Jul I Month Mean Monthly Gross Beta Concentrations in Drinking Water Jun I

Indicator Samples May I

I I:************************************

Apr I

a Mar I

I Feb I

Jan I

10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 Picocuries per Liter C-24

FIGURE C-4 Mean Monthly Tritium Concentrations in Drinking Water and Effluent Water Three Mile Island Nuclear Station, 2020 NOTE: The mean values are calculated using both the MDCs and Indicator Samples Control Samples the positive values.

500 NOTE: USEPA Drinking Water Limit for Tritium: 20,000 pCi/L Picocuries per Liter 400 300 200 I 100 I I i I I I I I I I I I 0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C-25 Month Station K1-1 (TMINS Liquid Discharge) 1000000 Picocuries per Liter 100000 10000 1000 100 10 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

FIGURE C-5 Mean Cesium-137 Concentrations in Aquatic Sediments Three Mile Island Nuclear Station, 1984 - 2020 Indicator Samples Control Samples 900 Significant Event

.Chernobyl April 1986 800 700 Picocuries per kilogram (dry) 600 C-26 500 400 300 200 100 0

1984 1991 1997 2004 2012 2019 Year

FIGURE C-6 Mean Quarterly Gross Beta Concentrations in Air Particulates Three Mile Island Nuclear Station, 1972 - 2020 Indicator t Control 0.4 Significant Events Major Atm. Nuclear Weapon Tests TMI-1 Critical June 1974 March 1972 June 1973 0.35 TMI-2 Critical March 1978 June 1974 September 1974 TMI-2 Accident March 1979 September 1976 November 1976 TMI-2 RB Purge June 1980 September 1977 March 1978 Chernobyl April 1986 December 1978 October 1980 0.3 Picocuries per Cubic Meter 0.25 C-27 0.2 0.15 0.1 0.05 0

1972 1978 1984 1990 1996 2002 2008 2014 2020 Year

FIGURE C-7 Mean Weekly Gross Beta Concentrations in Air Particulates Three Mile Island Nuclear Station, 2007 - 2020 0.100 0.090 Indicator Control 0.080 0.070 Picocuries per Cubic Meter 0.060 C-28 0.050 0.040 0.030 0.020 0.010 0.000 01/01/07 11/10/08 09/20/10 07/30/12 06/09/14 04/18/16 02/26/18 01/06/20 Month / Day / Year The high value on 11/24/2009 was caused by an airborne release on 11/21/2009

FIGURE C-8 Mean Quarterly Strontium-90 Concentrations in Cow Milk Three Mile Island Nuclear Station, 1979 - 2020 Indicator Samples t Control Samples 10 Significant Events Major Atm. Nuclear Weapon Tests TMI-2 Accident March 1979 December 1978 October 1980 9

TMI-2 RB Purge June 1980 Chernobyl April 1986 8

7 Picocuries per Liter 6

C-29 5

4 3

2 1

0 1979 1984 1989 1994 1999 2004 2009 2014 2019 Year

Intentionally left blank APPENDIX D DATA TABLES AND FIGURES COMPARISON LABORATORIES

Intentionally left blank The following section presents the results of data analysis performed by the QC laboratories, Exelon Industrial Services (EIS) and GEL Laboratories (GEL). Duplicate samples were obtained from several locations and media and were split with the primary laboratory, Teledyne Brown Engineering (TBE). Comparison of the results for most media were within expected ranges.

Intentionally left blank TABLE D-I.1 CONCENTRATIONS OF GROSS BETA IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB PERIOD Q9-1Q EIS 01/02/20 - 01/30/20 1.7 +/- 0.7 01/30/20 - 02/27/20 0.9 +/- 0.6 02/27/20 - 04/01/20 1.4 +/- 0.6 04/01/20 - 04/29/20 1.7 +/- 0.6 04/29/20 - 05/28/20 1.9 +/- 0.7 05/28/20 - 06/30/20 1.5 +/- 0.6 06/30/20 - 07/30/20 1.8 +/- 0.7 07/30/20 - 09/02/20 2.1 +/- 0.7 09/02/20 - 10/01/20 3.1 +/- 0.8 `

10/01/20 - 10/29/20 2.0 +/- 0.7 10/29/20 - 12/03/20 1.6 +/- 0.6 12/03/20 - 12/29/20 1.7 +/- 0.7 MEAN +/- 2 STD DEV 1.8 +/- 1.0 TABLE D-I.2 CONCENTRATIONS OF TRITIUM IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB PERIOD Q9-1Q GEL 01/02/20 - 04/01/20 < 136 04/01/20 - 06/30/20 < 137 06/30/20 - 10/04/20 < 118 10/04/20 - 12/29/20 < 158 MEAN -

TABLE D-I.3 CONCENTRATIONS OF IODINE-131 IN DRINKING WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB PERIOD Q9-1Q EIS 01/02/20 - 01/30/20 < 0.7 01/30/20 - 02/27/20 < 0.7 02/27/20 - 04/01/20 < 0.5 04/01/20 - 04/29/20 < 0.7 04/29/20 - 05/28/20 < 0.6 05/28/20 - 06/30/20 < 0.9 06/30/20 - 07/30/20 < 0.8 07/30/20 - 09/02/20 < 0.9 09/02/20 - 10/01/20 < 0.6 10/01/20 - 10/29/20 < 0.8 10/29/20 - 12/03/20 < 0.7 12/03/20 - 12/29/20 < 0.8 MEAN -

THE MEAN AND 2 STANDARD DEVIATION VALUES 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 THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 EIS Q9-1Q 01/02/20 - 01/30/20 < 3 < 3 < 6 < 3 < 6 < 3 < 5 < 3 < 3 < 11 < 4 01/30/20 - 02/27/20 < 4 < 5 < 9 < 5 < 9 < 5 < 7 < 5 < 5 < 17 < 8 02/27/20 - 04/01/20 < 4 < 5 < 9 < 4 < 9 < 4 < 8 < 4 < 5 < 18 < 6 04/01/20 - 04/29/20 < 4 < 5 < 9 < 5 < 8 < 4 < 8 < 4 < 5 < 20 < 8 04/29/20 - 05/28/20 < 5 < 6 < 13 < 6 < 11 < 6 < 8 < 5 < 6 < 26 < 10 05/28/20 - 06/30/20 < 5 < 5 < 9 < 5 < 10 < 5 < 7 < 4 < 5 < 24 < 9 06/30/20 - 07/30/20 < 4 < 4 < 7 < 5 < 9 < 4 < 7 < 4 < 4 < 17 < 6 07/30/20 - 09/02/20 < 4 < 4 < 8 < 4 < 7 < 4 < 6 < 4 < 4 < 14 < 5 09/02/20 - 10/01/20 < 4 < 4 < 8 < 4 < 8 < 4 < 6 < 4 < 4 < 15 < 5 10/01/20 - 10/29/20 < 4 < 4 < 9 < 4 < 10 < 5 < 7 < 5 < 5 < 23 < 8 10/29/20 - 12/03/20 < 6 < 6 < 14 < 6 < 8 < 5 < 7 < 5 < 6 < 26 < 11 12/03/20 - 12/29/20 < 6 < 6 < 12 < 6 < 14 < 6 < 9 < 5 < 6 < 26 < 12 D-2 MEAN - - - - - - - - - - -

TABLE D-II.1 CONCENTRATIONS OF STRONTIUM AND GAMMA EMITTERS IN FISH SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION LAB SITE PERIOD Sr-89 Sr-90 K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Cs-134 Cs-137 EIS INDP 11/20/20 3850 +/- 317 < 14 < 15 < 42 < 14 < 36 < 14 < 12 GEL INDP 11/20/20 < 24 < 8.9 D-3

TABLE D-III.1 CONCENTRATIONS OF GAMMA EMITTERS IN SEDIMENT SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 COLLECTION LAB SITE PERIOD K-40 Cs-134 Cs-137 EIS J2-1 12/01/20 13600 +/- 1770 < 121 < 134 D-4

TABLE D-IV.1 CONCENTRATIONS OF GAMMA EMITTERS AND STRONTIUM IN FOOD PRODUCT SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION LAB SITE TYPE PERIOD Be-7 K-40 I-131 Cs-134 Cs-137 Sr-89 Sr-90 EIS B10-2Q Cabbage 07/23/20 < 183 2590 +/- 339 < 31 < 22 < 21 GEL B10-2Q Cabbage 07/23/20 < 15.9 24 +/- 4.9 EIS H1-2Q Squash 06/25/20 246 +/- 120 3750 +/- 389 < 57 < 23 < 25 EIS H1-2Q Squash 07/23/20 734 +/- 135 3760 +/- 388 < 27 < 24 < 22 EIS H1-2Q Squash 08/26/20 1190 +/- 156 3840 +/- 373 < 32 < 17 < 19 EIS H1-2Q Squash 09/23/20 < 271 2160 +/- 390 < 45 < 32 < 34 D-5

TABLE D-V.1 CONCENTRATIONS OF GROSS BETA IN AIR PARTICULATE AND I-131 IN AIR IODINE SAMPLES COLLECED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION E1-2Q E1-2Q LAB PERIOD GROSS BETA I-131 EIS 01/02/20 - 01/09/20 19 +/- 2 < 11 01/09/20 - 01/16/20 18 +/- 2 < 9 01/16/20 - 01/23/20 26 +/- 2 < 8 01/23/20 - 01/30/20 16 +/- 2 < 10 01/30/20 - 02/06/20 20 +/- 2 < 11 02/06/20 - 02/13/20 15 +/- 2 < 8 02/13/20 - 02/20/20 25 +/- 2 < 12 02/20/20 - 02/27/20 24 +/- 2 < 11 02/27/20 - 03/05/20 18 +/- 2 < 12 03/05/20 - 03/11/20 15 +/- 2 < 16 03/11/20 - 03/19/20 19 +/- 2 < 18 03/19/20 - 03/26/20 16 +/- 2 < 23 03/26/20 - 04/01/20 13 +/- 2 < 19 04/01/20 - 04/09/20 16 +/- 2 < 19 04/09/20 - 04/16/20 20 +/- 2 < 20 04/16/20 - 04/23/20 23 +/- 2 < 17 04/23/20 - 04/29/20 12 +/- 2 < 18 04/29/20 - 05/07/20 15 +/- 2 < 15 05/07/20 - 05/14/20 16 +/- 2 < 19 05/14/20 - 05/21/20 20 +/- 2 < 16 05/21/20 - 05/28/20 11 +/- 2 < 19 05/28/20 - 06/04/20 17 +/- 2 < 14 06/04/20 - 06/11/20 19 +/- 2 < 19 06/11/20 - 06/18/20 14 +/- 2 < 20 06/18/20 - 06/24/20 17 +/- 2 < 18 06/24/20 - 06/30/20 23 +/- 3 < 28 06/30/20 - 07/08/20 23 +/- 2 < 10 07/08/20 - 07/16/20 19 +/- 2 < 15 07/16/20 - 07/23/20 25 +/- 2 < 11 07/23/20 - 07/30/20 30 +/- 2 < 11 07/30/20 - 08/05/20 25 +/- 3 < 15 08/05/20 - 08/13/20 32 +/- 2 < 20 08/13/20 - 08/20/20 29 +/- 2 < 22 08/20/20 - 08/27/20 32 +/- 3 < 25 08/27/20 - 09/02/20 18 +/- 2 < 17 09/02/20 - 09/10/20 27 +/- 2 < 11 09/10/20 - 09/17/20 18 +/- 2 < 26 09/17/20 - 09/24/20 32 +/- 3 < 14 09/24/20 - 10/01/20 35 +/- 3 < 17 10/01/20 - 10/08/20 24 +/- 2 < 17 10/08/20 - 10/15/20 23 +/- 2 < 15 10/15/20 - 10/22/20 22 +/- 2 < 15 10/22/20 - 10/29/20 16 +/- 2 < 24 10/29/20 - 11/06/20 30 +/- 2 < 18 11/06/20 - 11/12/20 44 +/- 3 < 21 11/12/20 - 11/19/20 26 +/- 2 < 23 11/19/20 - 11/25/20 32 +/- 3 < 38 11/25/20 - 12/03/20 24 +/- 2 < 16 12/03/20 - 12/09/20 18 +/- 2 < 33 12/09/20 - 12/16/20 53 +/- 3 < 21 12/16/20 - 12/23/20 24 +/- 2 < 22 12/23/20 - 12/29/20 30 +/- 3 < 28 MEAN +/- 2 STD DEV 23 +/- 16 -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES D-6

TABLE D-V.2 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION LAB SITE PERIOD Be-7 Cs-134 Cs-137 EIS E1-2Q 01/02/20 - 04/01/20 82 +/- 13 < 1.1 < 1.0 04/01/20 - 06/30/20 68 +/- 12 < 1.3 < 1.2 06/30/20 - 10/01/20 80 +/- 13 < 1.3 < 1.5 10/01/20 - 12/29/20 53 +/- 11 < 1.2 < 1.3 MEAN +/- 2 STD DEV 71 +/- 26 - -

D-7

TABLE D-VI.1 CONCENTRATIONS OF I-131 BY CHEMICAL SEPARATION, GAMMA EMITTERS, AND STRONTIUM IN MILK SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB SITE DATE I-131 K-40 Cs-134 Cs-137 Ba-140 La-140 Sr-89 Sr-90 EIS G2-1Q 01/15/20 < 0.8 967 +/- 74 < 5 < 6 < 25 < 8 EIS 02/12/20 < 0.6 1190 +/- 107 < 5 < 6 < 19 < 6 EIS 03/11/20 < 0.5 1430 +/- 87 < 3 < 4 < 17 < 5 EIS 03/25/20 < 0.9 1220 +/- 82 < 4 < 4 < 22 < 6 GEL 01/15/20 - 03/25/20 < 3.3 < 1.7 EIS 04/08/20 < 0.7 1370 +/- 106 < 5 < 5 < 23 < 7 EIS 04/23/20 < 0.6 1370 +/- 86 < 4 < 4 < 19 < 7 EIS 05/06/20 < 0.7 1410 +/- 106 < 4 < 5 < 22 < 5 EIS 05/20/20 < 0.4 1450 +/- 942 < 4 < 4 < 15 < 5 EIS 06/03/20 < 0.5 1460 +/- 108 < 5 < 5 < 20 < 8 EIS 06/17/20 < 0.6 1290 +/- 102 < 5 < 5 < 22 < 7 GEL 04/08/20 - 06/17/20 < 2.3 < 1.8 EIS 07/01/20 < 0.6 1410 +/- 106 < 5 < 5 < 20 < 7 D-8 EIS 07/15/20 < 0.8 1320 +/- 101 < 6 < 7 < 25 < 8 EIS 07/29/20 < 0.7 1330 +/- 104 < 5 < 5 < 20 < 6 EIS 08/12/20 < 0.7 1300 +/- 101 < 6 < 5 < 23 < 6 EIS 08/26/20 < 0.8 1210 +/- 103 < 6 < 7 < 24 < 8 EIS 09/09/20 < 0.6 1240 +/- 99 < 4 < 6 < 22 < 7 EIS 09/23/20 < 0.8 1460 +/- 108 < 5 < 5 < 21 < 6 GEL 07/01/20 - 09/23/20 < 2.6 < 1.8 EIS 10/07/20 < 0.8 1410 +/- 107 < 4 < 5 < 20 < 9 EIS 10/22/20 < 0.6 1470 +/- 110 < 4 < 5 < 25 < 7 EIS 11/04/20 < 0.8 1120 +/- 98 < 6 < 5 < 24 < 9 EIS 11/18/20 < 0.7 1250 +/- 101 < 5 < 5 < 21 < 6 EIS 12/09/20 < 0.8 1140 +/- 98 < 5 < 5 < 20 < 6 GEL 10/07/20 - 12/09/20 < 3.4 < 1.5 MEAN +/- 2 STD DEV 1310 +/- 264 - - - - - -

THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES

FIGURE D-1 MONTHLY GROSS BETA CONCENTRATIONS IN DRINKING WATER SAMPLES COLLECTED FROM TMINS LOCATION Q9-1Q, 2020 6.0 t QC-LAB 5.0 PRIMARY - LAB 4.0 pCi/liter D-9 3.0 2.0 1.0 0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec MONTH

FIGURE D-2 WEEKLY GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED FROM TMINS LOCATION E1-2Q, 2020 60 I QC - LAB 50 . PRIMARY - LAB 40 E-3 pCi/cubic meter D-10 30 20 10 0

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

APPENDIX E INTER-LABORATORY COMPARISON PROGRAM

Intentionally left blank Analytics Environmental Radioactivity Cross Check Program Table E.1 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 Table E.1 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)

DOE's Mixed Analyte Performance Evaluation Program (MAPEP)

Table E.2 Teledyne Brown Engineering Environmental Services Identification TBE Known Acceptance Month/Year Matrix Nuclide Units Evaluation (b)

Number Value Value (a) Range February 2020 20-GrF42 AP Gross Alpha Bq/sample 0.676 1.24 0.37 - 2.11 A Gross Beta Bq/sample 2.03 2.00 1.00 - 3.00 A 20-MaS42 Soil Ni-63 Bq/kg 0.01 (1) A Sr-90 Bq/kg 348 340 238 - 442 A 20-MaW42 Water Ni-63 Bq/L 11.6 11.1 7.8 - 14.4 A Pu-238 Bq/L 0.926 0.94 0.66 - 1.22 A Pu-239/240 Bq/L 0.712 0.737 0.516 - 0.958 A 20-RdF42 AP U-234/233 Bq/sample 0.0416 0.075 0.053 - 0.098 N(3)

U-238 Bq/sample 0.0388 0.078 0.055 - 0.101 N(3) 20-RdV42 Vegetation Cs-134 Bq/sample 3.23 3.82 2.67 - 4.97 A Cs-137 Bq/sample 2.64 2.77 1.94 - 3.60 A Co-57 Bq/sample 0.0281 (1) A Co-60 Bq/sample 2.62 2.79 1.95 - 3.63 A Mn-54 Bq/sample 4.3 4.58 3.21 - 5.95 A Sr-90 Bq/sample 0.396 0.492 0.344 - 0.640 A Zn-65 Bq/sample 3.93 3.79 2.65 - 4.93 A August 2020 20-GrF43 AP Gross Alpha Bq/sample 0.267 0.528 0.158 - 0.989 A Gross Beta Bq/sample 0.939 0.915 0.458 - 1.373 A 20-MaS43 Soil Ni-63 Bq/kg 438 980 686 - 1274 N(4)

Tc-99 Bq/kg 1.11 (1) A 20-MaW43 Water Ni-63 Bq/L 0.175 (1) A Tc-99 Bq/L 8.8 9.4 6.6 - 12.2 A 20-RdV43 Vegetation Cs-134 Bq/sample 3.635 4.94 3.46 - 6.42 W Cs-137 Bq/sample 0.0341 (1) A Co-57 Bq/sample 5.855 6.67 4.67 - 8.67 W Co-60 Bq/sample 3.122 4.13 2.89 - 5.37 W Mn-54 Bq/sample 4.524 5.84 4.09 - 7.59 A Sr-90 Bq/sample 1.01 1.39 0.97 - 1.81 W Zn-65 Bq/sample 4.706 6.38 4.47 - 8.29 W (a) The MAPEP 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) DOE/MAPEP evaluation:

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) False positive test (2) Sensitivity evaluation (3) See NCR 20-13 (4) See NCR 20-20 (Page 1 of 1)

ERA Environmental Radioactivity Cross Check Program Table E.3 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)

TABLE E.6 DOE's Mixed Analyte Performance Evaluation Program (MAPEP)

GEL Laboratories (Gamma, Gross Alpha/Beta, H-3 & Sr-90)

Identification Reported Known Quarter/Year Matrix Nuclide Units Acceptance Range Evaluation (b)

Number Value Value (a) 2nd/2020 20-GrW42 Water Gr-A Bq/L 1.01 1.03 0.31 - 1.75 A Gr-B Bq/L 4.18 4.24 2.12- 6.36 A 20-MaW42 Water H-3 Bq/L 193 196 137 - 255 A Sr-90 Bq/L 0.0122 False Positive Test A Cs-134 Bq/L 17 18.5 13.0 - 24.1 A Cs-137 Bq/L 12 11.3 7.9 - 14.7 A Co-60 Bq/L 11 10.6 7.4 - 13.8 A Fe-55 Bq/L 18.2 17.8 12.5 - 23.1 A K-40 Bq/L -0.0485 False Positive Test A Mn-54 Bq/L 20.6 19.6 13.7 - 25.5 A Zn-65 Bq/L 23.9 22.2 15.5 - 28.9 A 4th/2020 20-MaW43 Water H-3 Bq/L 330 360 252 - 468 A Sr-90 Bq/L 9.97 11.6 8.1 - 15.1 A Cs-134 Bq/L 13.9 15.2 10.6 - 19.8 A Cs-137 Bq/L 15.1 14.3 10.0 - 18.6 A Co-60 Bq/L 12.9 12.2 8.5 - 15.9 A Fe-55 Bq/L 29.2 32.9 23.0 - 42.8 A K-40 Bq/L -0.763 False Positive Test A Mn-54 Bq/L -0.0032 False Positive Test A Zn-65 Bq/L 18.9 16.9 11.8 - 22 A (a) The MAPEP 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) DOE/MAPEP evaluation:

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 1 of 1)

TABLE E.7 ERA Environmental Radioactivity Cross Check Program GEL Laboratories (Gamma, Gross Alpha/Beta, H-3 & Sr-89/90)

Identification Reported Known Acceptance Quarter/Year Matrix Nuclide Units Evaluation (b)

Number Value Value (a) Limits 1st/2020 RAD-120 Water Cs-134 pCi/L 21.5 22.9 17.5 - 25.6 A Cs-137 pCi/L 217 220 198 - 244 A Co-60 pCi/L 97.7 91.2 82.1 - 103 A I-131 pCi/L 23.7 29.9 24.9 - 34.9 N(1)

I-131 pCi/L 31.8 29.9 24.9 - 34.9 A Zn-65 pCi/L 332 298 268 - 348 A Gr-A pCi/L 67.1 58.9 30.8 - 73.3 A Gr-A pCi/L 55.4 58.9 30.8 - 73.3 A Gr-B pCi/L 20.0 21.0 12.6 - 29.1 A H-3 pCi/L 15,200 17,800 15,600 - 19,600 N(1)

H-3 pCi/L 17,700 17,800 15,600 - 19,600 A Sr-89 pCi/L 73.3 59.3 47.6 - 67.1 N(1)

Sr-89 pCi/L 70.8 59.3 47.6 - 67.1 N(1)

Sr-90 pCi/L 38.3 36.5 26.8 - 42.1 A Sr-90 pCi/L 30.6 36.5 26.8 - 42.1 A 2nd/2020 MRAD-32 Water Cs-134 pCi/L 1,420 1,520 1,150 - 1,670 A Cs-137 pCi/L 2,440 2,390 2,050 - 2,720 A Co-60 pCi/L 2,890 2,760 2,380 - 3,170 A Fe-55 pCi/L 140 152 89.3 - 221 A Mn-54 pCi/L <6.25 <100 <100 A Zn-65 pCi/L 1,330 1,190 1,060 - 1,500 A Sr-90 pCi/L 426 447 322 - 552 A Gr-A pCi/L 67.6 165 60.2 - 228 A Gr-B pCi/L 143 158 79.0 - 217 A H-3 pCi/L 5,990 6,280 4,730 - 7,640 A RAD-121 Water I-131 pCi/L 27.5 28.9 24.1 - 33.8 A Sr-89 pCi/L 68.8 60.1 48.3 - 67.9 N(2)

Sr-89 pCi/L 71.6 60.1 48.3 - 67.9 N(2)

H-3 pCi/L 13,100 14,100 12,300 - 15,500 A 3rd/2020 RAD-122 Water Cs-134 pCi/L 23.0 22.3 17.0 - 25.0 A Cs-137 pCi/L 76.5 73.0 65.7 - 83.0 A Co-60 pCi/L 97.9 86.1 77.5 - 97.0 N(3)

I-131 pCi/L 29.9 26.1 21.7 - 30.8 A Zn-65 pCi/L 96.3 82.9 74.6 - 99.6 A Gr-A pCi/L 54.3 52.4 27.3 - 65.6 A Gr-B pCi/L 24.7 24.3 15.0 - 32.3 A H-3 pCi/L 17,800 20,300 17,800 - 22,300 A H-3 pCi/L 20,200 20,300 17,800 - 22,300 A Sr-89 pCi/L 61.7 68.9 56.2 - 77.1 A Sr-90 pCi/L 18.2 19.5 13.9 - 23.1 A 4th/2020 MRAD-31 Water Cs-134 pCi/L 849 911 688 - 1,000 A Cs-137 pCi/L 1,540 1,510 1,290 - 1,720 A Co-60 pCi/L 1,660 1,560 1,350 - 1,790 A Fe-55 pCi/L 267 298 175 - 433 A Mn-54 pCi/L <4.61 <100 <100 A Zn-65 pCi/L 1,010 917 816 - 1,160 A Sr-90 pCi/L 917 787 567 - 973 A Gr-A pCi/L 100 111 40.5 - 153 A Gr-B pCi/L 181 194 97.0 - 267 A H-3 pCi/L 11,600 12,000 9,040 - 14,600 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) CARR200224-1274 (2) No Information (3) CARR200902-1287 (Page 1 of 1)

TABLE E.8 Analytics Environmental Radioactivity Cross Check Program GEL Laboratories (Gamma and Sr-89/90 only)

Identification Reported Known Acceptance Quarter/Year Matrix Nuclide Units Evaluation (b)

Number Value Value (a) Limits 1st/2020 E13170 Water Cs-134 pCi/L 153 154 0.99 A Cs-137 pCi/L 208 185 1.12 A Co-58 pCi/L 221 196 1.13 A Co-60 pCi/L 259 236 1.10 A Fe-59 pCi/L 179 168 1.06 A I-131 pCi/L 102 93 1.10 A Mn-54 pCi/L 248 216 1.15 A Zn-65 pCi/L 305 261 1.17 A 2nd/2020 E13174 Water Cs-134 pCi/L 136 148 0.92 A Cs-137 pCi/L 104 105 0.99 A Co-58 pCi/L 105 102 1.03 A Co-60 pCi/L 205 198 1.04 A Fe-59 pCi/L 91 81 1.13 A I-131 pCi/L 105 102 1.03 A Mn-54 pCi/L 147 135 1.09 A Zn-65 pCi/L 249 227 1.10 A 3rd/2020 E13178 Water Cs-134 pCi/L 181 201 0.90 A Cs-137 pCi/L 263 251 1.05 A Co-58 pCi/L 190 180 1.05 A Co-60 pCi/L 404 380 1.06 A Fe-59 pCi/L 226 201 1.12 A I-131 pCi/L 98 98 1.00 A Mn-54 pCi/L 206 181 1.14 A Zn-65 pCi/L 302 271 1.12 A 4th/2020 E13182 Water Cs-134 pCi/L 114 114 1.00 A Cs-137 pCi/L 137 135 1.02 A Co-58 pCi/L 95.4 89.2 1.07 A Co-60 pCi/L 174 161 1.08 A Fe-59 pCi/L 137 119 1.16 A I-131 pCi/L 97 96 1.02 A Mn-54 pCi/L 165 151 1.09 A Zn-65 pCi/L 229 201 1.14 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 laboratory's internal acceptance criteria of 75% - 125%:

A = Acceptable - Reported value falls within the Acceptance Limits N = Not Acceptable - Reported value falls outside of the Acceptance Limits (Page 1 of 1)

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

Intentionally left blank Docket No: 50-289 50-320 THREE MILE ISLAND NUCLEAR STATION UNITS 1 AND 2 Annual Radiological Groundwater Protection Program Report (ARGPPR) 1 January through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services Exelon Generation Three Mile Island Nuclear Station Middletown, PA 17057 April 2021

Intentionally left blank Table Of Contents I. Summary and Conclusions .............................................................................................. 1 II. Introduction...................................................................................................................... 2 A. Objectives of the RGPP ....................................................................................... 3 B. Implementation of the Objectives ........................................................................ 3 C. Program Description ............................................................................................ 4 D. Characteristics of Tritium (H-3)............................................................................ 4 III. Program Description....................................................................................................... 6 A. Sample Analysis .................................................................................................. 6 B. Data Interpretation ............................................................................................... 6 IV. Results and Discussion ................................................................................................. 8 A. Groundwater Results ........................................................................................... 8 B. Surface Water Results ......................................................................................... 9 C. Storm Water Results ........................................................................................... 9 D. Precipitation Water Results ................................................................................. 9 E. Leaks, Spills, and Releases............................................................................... 10 F. Actions Taken .................................................................................................... 10 G. Missed Samples ................................................................................................ 10 i

Intentionally left blank Appendices Appendix A Location Designation Tables Table A-1 Radiological Groundwater Protection Program - Sampling Locations, Distance and Direction, Three Mile Island Nuclear Station, 2020 Figures Figure A-1 Sampling Locations at the Three Mile Island Nuclear Station, 2020 Appendix B Data Tables Tables Table B-I.1 Concentrations of Tritium, Strontium, Gross Alpha, and Gross Beta in Groundwater Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 Table B-I.2 Concentrations of Gamma Emitters in Groundwater Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table B-I.3 Concentrations of Hard-To-Detects in Groundwater Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Generating Station, 2020 Table B-II.1 Concentrations of Tritium in Surface Water Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 Table B-III.1 Concentrations of Tritium in Storm Water Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 Table B-III.2 Concentrations of Gamma Emitters in Storm Water Samples Collected in the Vicinity of Three Mile Island Nuclear Station, 2020 Table B-IV.1 Concentrations of Tritium in Precipitation Water Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 ii

Appendix C Data Tables - Comparison Tables Table C-I.1 Concentrations of Tritium, Strontium, Gross Alpha and Gross Beta in Groundwater Split Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 Table C-I.2 Concentrations of Gamma Emitters in Groundwater Split Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 Table C-I.3 Concentrations of Hard-To-Detects in Groundwater Split Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Generating Station, 2020 Table C-II.1 Concentrations of Tritium in Surface Water Split Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 Table C-III.1 Concentrations of Tritium in Precipitation Water Split Samples Collected as Part of the Radiological Groundwater Protection Program, Three Mile Island Nuclear Station, 2020 iii

I. Summary and Conclusions In 2006, Exelon instituted a comprehensive program to evaluate the impact of station operations on groundwater and surface water in the vicinity of Three Mile Island Nuclear Station. This report covers groundwater, surface water, storm water, and precipitation samples collected from the environment, both on and off station property in 2020. During that time period 307 analyses were performed on 145 samples from 60 locations.

In assessing all the data gathered for this report, it was concluded that the operation of Three Mile Island Nuclear Station had no adverse radiological impact on the environment.

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

In the case of tritium, Exelon specified that its laboratories achieve a lower limit of detection 10 times lower than that required by federal regulation.

Strontium-89 (Sr-89) and Strontium-90 (Sr-90) were not detected at a concentration greater than their respective LLD of 10 and 1 picocurie per liter (pCi/L) in the groundwater samples tested.

Tritium was not detected in any ground water, surface water, storm water or precipitation water samples at concentrations greater than the United States Environmental Protection Agency (USEPA) drinking water standard (and the Nuclear Regulatory Commission Reporting Limit) of 20,000 pCi/L. Low levels of tritium were detected at concentrations greater than the LLD of 200 pCi/L in 32 of 50 groundwater monitoring locations. The groundwater tritium concentrations ranged from 187 +/- 117 pCi/L to 2,770 +/- 337 pCi/L. Tritium that was detected in groundwater at the Station is believed to be the result of previous tank leakage, historical releases, the recapture of gaseous tritium releases via rainwater, and/or background from external sources greater than 200 pCi/L. Tritium was not detected at any surface water or stormwater location. Tritium was detected in 4 of 8 precipitation water locations. The concentrations ranged from 198 +/- 123 to 714 +/- 151 pCi/L.

Gross Alpha in the dissolved and suspended fractions were performed on 21 groundwater samples during the second quarter sampling in 2020. Gross Alpha (dissolved) was not detected at any of the 21 groundwater locations. Gross Alpha (suspended) was detected at 1 of the 21 groundwater locations at a concentration of 3.0 +/- 1.1 pCi/L.

Hard-To-Detect analyses include Fe-55, Ni-63, Am-241, Cm-242, Cm-243/244, Pu-238, Pu-239/240, U-234, U-235 and U-238. Only Fe-55 and Ni-63 were analyzed in 2020. Action levels trigger monitoring requirements for these analyses.

Intentionally left blank II. Introduction The Three Mile Island Nuclear Station (TMINS) established a revised and more comprehensive groundwater monitoring program in 2006 as part of an Exelon Nuclear fleetwide assessment.

Conestoga Rovers & Associates (CRA) performed the initial assessment. CRA prepared a Hydrogeologic Investigation Report (HIR) for Exelon to determine whether groundwater at and near TMINS has been adversely impacted by any releases of radionuclides. The CRA report documents the results of the May 2006 Hydrogeologic Investigation Work Plan. CRA assessed groundwater quality at the Station and identified locations designated as Areas for Further Evaluation. The results and conclusions of this Phase 1 study were made available to state and federal regulators, as well as the public on an Exelon web site for station specific reports.

As a result of the Phase 1 study, the Radiological Groundwater Protection Program (RGPP) was revised to a long term monitoring program. This report covers those analyses performed by Teledyne Brown Engineering (TBE) and Exelon Industrial Services (EIS)/GEL Laboratories on well water, surface water, storm water, and precipitation water samples collected in 2020. TMINS groundwater movement is into the Susquehanna River which surrounds the station on all sides.

In September 2015, GHD completed an additional five-year update hydrogeologic investigation report for the Station (NEI 07-07, Hydrogeologic Investigation Report). The referenced report summarized station activities since the 2006 hydrogeologic investigation report, including changes at the Station as well as RGPP sampling activities and groundwater flow. Relevant conclusions from the report are:

• None of the AFEs identified in 2006 indicate current impacts to groundwater and are no longer considered AFEs.

• One new AFE, AFE-TMI-6-BWST, was identified based on laboratory analytical data.

• In July 2012, elevated tritium concentrations were noted for a sample collected from an electric vault west of MS-22. The source of this elevated tritium concentration was believed to be the BWST.

• Tritium is not migrating off of the Station property at concentrations greater than the USEPA Drinking Water Standard of 20,000 pCi/L.

• Gamma-emitting radionuclides associated with licensed plant operations were not detected at concentrations greater than their respective LLDs.

• Strontium 89 or 90 were not detected at concentrations greater than their respective LLDs.

In December 2019, GHD completed an additional five-year update hydrogeologic investigation report for the Station (NEI 07-07, Hydrogeologic Investigation Report). The referenced report summarized station activities since the 2015 hydrogeologic investigation report, including changes at the Station as well as RGPP sampling activities and groundwater flow. Relevant conclusions from the report are:

• AFE-TMI-6-BWST, 1 BWST is retained as an Area of Further Evaluation (AFE)

This report covers those analyses performed by Teledyne Brown Engineering (TBE) and Gel Laboratories (subcontracted from Exelon Industrial Services) on samples collected in 2020.

A. Objectives of the RGPP The long-term objectives of the Radiological Groundwater Protection Program (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. Notify stakeholders in a timely manner for new leaks, spills, or other detections with potential radiological significance.

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 Three Mile Island Nuclear Station as discussed below:

1. Three Mile Island Nuclear Station continues to sample and monitor the groundwater at the station in accordance with station procedures.

Sample frequencies and locations are adjusted based on monitoring results and investigations.

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

3. Three Mile Island Nuclear Station will continue to perform routine sampling and radiological analysis of water from selected locations.

4. Three Mile Island Nuclear Station has implemented procedures to identify and report leaks, spills, or other detections with potential radiological significance in a timely manner.

5. Three Mile Island Nuclear Station staff and consulting hydrogeologist assess analytical results on an ongoing basis to identify adverse trends.

C. Program Description

1. Sample Collection Sample locations can be found in Table A-1 and Figures A-1 and A-2, Appendix A.

Groundwater, Surface Water, Storm Water, and Precipitation Samples of water are collected, managed, transported and analyzed in accordance with approved procedures. Groundwater, surface water, storm water and precipitation are collected. Sample locations, sample collection frequencies and analytical frequencies are controlled in accordance with approved station procedures. Contractor and/or station personnel are trained in the collection, preservation management and shipment of samples, as well as in documentation of sampling events. For split samples, collectors will periodically collect samples that are sent to Exelon Industrial Services/GEL Laboratories to confirm that TBE is producing comparable data. Analytical laboratories are subject to internal quality assurance programs, industry cross-check programs, as well as nuclear industry audits.

Station personnel review and evaluate all analytical data deliverables as data are received.

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

D. Characteristics of Tritium (H-3)

Tritium (chemical symbol H-3) is a radioactive isotope of hydrogen. The most common form of tritium is tritium oxide, which is also called "tritiated water." 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 is created in the environment from naturally-occurring processes both cosmic and subterranean, as well as from anthropogenic (i.e.,

man-made) sources. Tritium is produced naturally in the upper atmosphere when cosmic rays strike air molecules. This cosmogenic tritium combines with oxygen to form tritiated water, which will then enter the hydrologic cycle. Below ground, lithogenic tritium is produced by the bombardment of natural lithium present in crystalline rocks by neutrons produced by the radioactive decay of naturally abundant uranium and thorium. Lithogenic production of tritium is usually negligible compared to other sources due to the limited abundance of lithium in rock. The lithogenic tritium is introduced directly to groundwater.

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

The chemical properties of tritium are essentially those of ordinary hydrogen. 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, all tritium is essentially cleared. Organically bound tritium (tritium that is incorporated in organic compounds) can remain in the body for a longer period.

Tritium has a radiological half-life of approximately 12.3 years. It decays spontaneously to Helium-3 (He-3). 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.

III. Program Description A. Sample Analysis This section describes the general analytical methodologies used by TBE and Exelon Industrial Services (EIS)/GEL Laboratories to analyze the environmental samples for radioactivity for the Three Mile Island Nuclear Station RGPP in 2020.

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

1. Concentrations of gamma-emitters in groundwater and storm water

2. Concentrations of strontium in groundwater

3. Concentrations of tritium in groundwater, surface water, precipitation water and storm water

4. Concentrations of Am-241 in groundwater

5. Concentrations of Cm-242 and Cm-243/244 in groundwater

6. Concentrations of Pu-238 and PU-239/240 in groundwater

7. Concentrations of U-234, U-235 and U-238 in groundwater

8. Concentrations of Fe-55 in groundwater

9. Concentrations of Ni-63 in groundwater

10. Concentrations of Gross Alpha (Dissolved and Suspended) in groundwater B. Data Interpretation

1. Lower Limit of Detection and Minimum Detectable Concentration The lower limit of detection (LLD) is specified by federal regulation as a minimum sensitivity value that must be achieved routinely by the analytical parameter.

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).

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

Gamma spectroscopy results for each type of sample were grouped as follows:

For groundwater, surface water, and storm water 13 nuclides, Be-7, K-40, Mn-54, Co-58, Fe-59, Co-60, Zn-65, Nb-95, Zr-95, Cs-134, Cs-137, Ba-140 and La-140 were reported.

The radio-analytical laboratory counts tritium results to an LLD of 200 pCi/L. Typically, the lowest positive measurement will be reported within a range of 40 - 240 pCi/L or 140 +/- 100 pCi/L. Clearly, these sample results cannot be distinguished as different from background at this concentration.

IV. Results and Discussion A. Groundwater Results Samples were collected from on and off-site wells in accordance with the station radiological groundwater protection program. Analytical results and anomalies are discussed below.

Tritium Samples from 50 locations were analyzed for tritium activity. Tritium values ranged from the detection limit to 2,770 pCi/L.

(Table B-I.1, Appendix B)

Tritium Split Samples Samples from 9 locations were analyzed for tritium activity. Tritium values ranged from the detection limit to 535 pCi/L.

(Table C-I.1, Appendix C)

Strontium Sr-89 and Sr-90 were not detected above their required detection limits of 10 and 1.0 pCi/L, respectively. (Table B-I.1, Appendix B)

Strontium Split Samples Sr-89 and Sr-90 were not detected above their required detection limits of 10 and 1.0 pCi/L, respectively. (Table C-I.1, Appendix C)

Gross Alpha (dissolved and suspended)

Gross Alpha analysis in the dissolved and suspended fractions were performed on 21 groundwater samples during the third quarter sampling in 2020. Gross Alpha (dissolved) was not detected at any of the groundwater locations. Gross Alpha (suspended) was detected at one of the groundwater locations at a concentration of 3.0 pCi/L.

(Table B-I.1, Appendix B)

Gross Alpha (total) Split Samples Gross Alpha was analyzed on one split sample in 2020. Gross Alpha (total) was not detected at this location. (Table C-I.1, Appendix C)

Gamma Emitters Gamma-emitting nuclides were analyzed at 50 locations in 2020.

Naturally-occurring K-40 was detected in 1 sample at a concentration of 36 +/- 24 pCi/L. No other gamma-emitting nuclides were detected.

(Table B-I.2, Appendix B)

Gamma Emitters Split Samples Gamma-emitting nuclides were analyzed at 5 locations in 2020. No gamma-emitting nuclides were detected in this sample.

(Table C-I.2, Appendix C)

Hard-To-Detect Only Fe55 and Ni-63 from the Hard-To-Detect analyses list (including Am-241, Cm-242, Cm-243/244, Pu-238, Pu-239/240, U-234, U-235, U-238), were analyzed at 7 locations in 2020. Neither Fe-55 nor Ni-63 were detected in any sample. (Table B-I.3, Appendix B)

Hard-To-Detect Split Samples Hard to detects were not analyzed on any split samples in 2020.

(Table C-I.3, Appendix C)

B. Surface Water Results Samples were collected from surface water locations in accordance with the station radiological groundwater protection program. Analytical results and anomalies are discussed below.

Tritium Three locations analyzed for tritium in 2020. Tritium was not detected above the required detection limit of 200 pCi/L in any of the 5 samples analyzed. (Table B-II.1, Appendix B)

Tritium Split Samples Two locations analyzed for tritium in 2020. Tritium was not detected above the required detection limit of 200 pCi/L in either sample analyzed.

(Table C-II.1, Appendix C)

C. Storm Water Results Samples were collected from storm water locations in accordance with the station radiological groundwater protection program. Analytical results and anomalies are discussed below.

Tritium One location analyzed for tritium. Tritium was not detected in any of the 4 samples. (Table B-III.1, Appendix B)

Gamma Emitters Four samples from one location were analyzed for gamma-emitting nuclides.

No gamma-emitting nuclides were detected. (Table B-III.2, Appendix B)

D. Precipitation Water Results Samples were collected at 8 locations. The following analyses were performed:

Tritium Samples from 8 locations were analyzed for tritium activity. Tritium activity was detected at 4 of 8 locations. The concentrations ranged from 198 to 714 pCi/L. (Table B-IV.1, Appendix B)

Tritium Split Samples Samples from one location were analyzed for tritium activity. Tritium was detected in 2 of the 3 samples. The concentrations ranged from 189 to 539 pCi/L. (Table C-III.1, Appendix C).

E. Leaks, Spills, and Releases There were no leaks, spills or releases in 2020.

F. Actions Taken There were no compensatory/corrective actions taken in 2020.

G. Missed Samples The 2020 second quarter RGPP well sampling event was cancelled due to the Covid-19 pandemic. The decision to cancel the sampling event was approved by the Plant Management Committee and recommended by Corporate Environmental. It was determined that missing one quarter of sampling would be low risk, low impact. Sample collection resumed on schedule during the third quarter 2020.

No precipitation samples were taken during the 3rd quarter of 2020. This was a procedural gap that had no regulatory impact and AR 04415986 documents the nonconformance to procedural requirements.

Intentionally left blank APPENDIX A LOCATION DESIGNATION & DISTANCE

Intentionally left blank TABLE A-1: Radiological Groundwater Protection Program - Sampling Locations, Three Mile Island Nuclear Station, 2020 Site Site Type 48S Production Potable Well EDCB Storm Water MS-1 Monitoring Well MS-2 Monitoring Well MS-3 Monitoring Well MS-4 Monitoring Well MS-5 Monitoring Well MS-7 Monitoring Well MS-8 Monitoring Well MS-20 Monitoring Well MS-21 Monitoring Well MS-22 Monitoring Well MW-1 Monitoring Well MW-2 Monitoring Well MW-TMI-1D Monitoring Well MW-TMI-2D Monitoring Well MW-TMI-3I Monitoring Well MW-TMI-4I Monitoring Well MW-TMI-4S Monitoring Well MW-TMI-6D Monitoring Well MW-TMI-6I Monitoring Well MW-TMI-7S Monitoring Well MW-TMI-8S Monitoring Well MW-TMI-9I Monitoring Well MW-TMI-9S* Monitoring Well MW-TMI-10D Monitoring Well MW-TMI-10I Monitoring Well MW-TMI-10S Monitoring Well MW-TMI-12S Monitoring Well MW-TMI-13I Monitoring Well MW-TMI-14D Monitoring Well MW-TMI-14I Monitoring Well MW-TMI-16D Monitoring Well MW-TMI-18D Monitoring Well MW-TMI-19I Monitoring Well MW-TMI-20I Monitoring Well MW-TMI-21D Monitoring Well MW-TMI-21I Monitoring Well MW-TMI-21S Monitoring Well MW-TMI-22D Monitoring Well MW-TMI-22I Monitoring Well MW-TMI-22S Monitoring Well NW-A Production Well NW-B Production Well NW-C Production Well NW-CW Clearwell OS-14 Monitoring Well OS-16 Monitoring Well OS-18 Monitoring Well OSF Production Potable Well RW-1 Monitoring Well SW-E-1 Surface Water SW-E-2 Surface Water SW-E-3 Surface Water TRAINING CENTER Offsite Monitoring Well TM-PR-EDCB Precipitation Water TM-PR-ESE Precipitation Water TM-PR-MS-1 Precipitation Water TM-PR-MS-2 Precipitation Water TM-PR-MS-4 Precipitation Water TM-PR-MS-8 Precipitation Water TM-PR-MS-20 Precipitation Water TM-PR-MS-22 Precipitation Water TM-PR-MW-22S Precipitation Water TM-PR-RW-1 Precipitation Water

• NO WATER PRESENT TO SAMPLE A-1

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• MW* 2 MW-TMl-1D MW-TMl-22I e e.e MW-3 MW..TMl -22O NW.CW e

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.... RGPP Groundwater Sampling Locations J. l'J N()Rf,,WJDfAY at Three Mile Island Nuclear St ation Figure A-1 Sampling Locations at the Three Mile Island Nuclear Station, 2020

APPENDIX B DATA TABLES

Intentionally left blank TABLE B-I.1 CONCENTRATIONS OF TRITIUM, STRONTIUM, AND GROSS ALPHA IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICALGROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION Gr-A Gr-A SITE DATE H-3 Sr-89 Sr-90 (Dis) (Sus) 48S 02/06/20 < 174 48S 08/20/20 < 189 < 6.5 < 0.8 < 2.0 < 1.0 48S 11/17/20 < 196 MS-1 02/04/20 < 189 MS-1 02/04/20 NP < 195 MS-1 08/21/20 < 176 MS-2 02/05/20 403 +/- 138 MS-2 08/19/20 216 +/- 118 < 6.0 < 0.8 < 0.4 < 0.6 MS-2 11/13/20 < 189 MS-3 02/05/20 315 +/- 131 MS-3 08/19/20 305 +/- 122 < 6.9 < 0.7 < 0.6 < 0.6 MS-3 11/13/20 < 183 MS-4 08/19/20 < 169 MS-5 02/05/20 < 192 MS-5 08/18/20 < 173 < 7.0 < 0.7 < 1.5 < 0.6 MS-5 11/13/20 < 186 MS-7 02/05/20 < 194 MS-7 08/19/20 < 172 < 7.4 < 0.8 < 0.4 < 0.9 MS-7 11/11/20 < 172 MS-7 11/11/20 DUP < 193 MS-8 02/05/20 244 +/- 129 MS-8 08/18/20 252 +/- 121 < 4.9 < 0.7 < 0.5 3.0 +/- 1.1 MS-8 11/13/20 230 +/- 125 MS-20 02/04/20 496 +/- 143 MS-20 02/04/20 DUP 382 +/- 130 MS-20 08/18/20 304 +/- 122 < 7.5 < 0.9 < 0.4 < 0.9 MS-20 11/13/20 250 +/- 127 MS-21 02/04/20 < 195 MS-21 08/18/20 240 +/- 119 < 6.7 < 0.9 < 0.2 < 0.9 MS-21 11/13/20 < 195 MS-22 02/04/20 1110 +/- 180 MS-22 02/04/20 NP 1100 +/- 179 MS-22 08/18/20 1180 +/- 189 < 5.9 < 0.7 < 0.7 < 0.6 MS-22 11/13/20 805 +/- 169 MW-1 08/21/20 < 177 MW-2 08/21/20 < 176 MW-TMI-1D 08/21/20 189 +/- 116 MW-TMI-2D 08/21/20 < 173 MW-TMI-3I 02/04/20 323 +/- 129 MW-TMI-3I 08/21/20 399 +/- 124 < 6.3 < 0.6 < 2.1 < 4.0 MW-TMI-3I 08/21/20 DUP 431 +/- 131 < 6.1 < 0.9 < 1.6 < 1.8 MW-TMI-3I 11/11/20 310 +/- 122 MW-TMI-3I 11/11/20 DUP 257 +/- 129 MW-TMI-4I 08/21/20 206 +/- 120 MW-TMI-4I 08/21/20 DUP < 177 MW-TMI-4S 08/21/20 248 +/- 119 MW-TMI-6D 02/05/20 < 189 MW-TMI-6D 08/19/20 301 +/- 123 < 5.1 < 0.9 < 0.6 < 0.9 MW-TMI-6D 11/11/20 < 177 MW-TMI-6I 02/05/20 < 191 NP = Non-purge study samples B-1

TABLE B-I.1 CONCENTRATIONS OF TRITIUM, STRONTIUM, AND GROSS ALPHA IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICALGROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION Gr-A Gr-A SITE DATE H-3 Sr-89 Sr-90 (Dis) (Sus)

MW-TMI-6I 08/19/20 200 +/- 117 < 7.1 < 0.7 < 0.6 < 1.0 MW-TMI-6I 11/11/20 < 176 MW-TMI-7S 08/19/20 199 +/- 116 MW-TMI-8S 08/21/20 < 171 MW-TMI-9I 08/19/20 < 183 MW-TMI-10D 08/19/20 298 +/- 121 MW-TMI-10I 02/05/20 533 +/- 142 MW-TMI-10I 02/05/20 NP 508 +/- 140 MW-TMI-10I 08/19/20 717 +/- 144 MW-TMI-10I 08/19/20 DUP 534 +/- 131 MW-TMI-10S 02/05/20 375 +/- 132 MW-TMI-10S 02/05/20 NP 371 +/- 134 MW-TMI-10S 08/19/20 622 +/- 137 MW-TMI-12S 02/04/20 < 197 MW-TMI-12S 08/19/20 < 176 < 4.1 < 0.7 < 0.3 < 0.6 MW-TMI-12S 11/13/20 < 186 MW-TMI-13I 02/05/20 < 194 MW-TMI-13I 08/21/20 < 182 MW-TMI-13I 08/21/20 DUP < 173 MW-TMI-14D 02/05/20 < 192 MW-TMI-14D 08/21/20 241 +/- 120 MW-TMI-14I 02/05/20 < 194 MW-TMI-14I 02/05/20 DUP < 190 MW-TMI-14I 08/21/20 < 179 MW-TMI-14I 08/21/20 DUP < 181 MW-TMI-16D 08/21/20 583 +/- 137 MW-TMI-18D 08/21/20 < 177 MW-TMI-19I 08/21/20 < 179 MW-TMI-20I 08/19/20 510 +/- 130 MW-TMI-21D 02/04/20 2770 +/- 337 MW-TMI-21D 02/04/20 NP 2830 +/- 344 MW-TMI-21D 08/18/20 2290 +/- 291 MW-TMI-21I 02/04/20 961 +/- 166 MW-TMI-21I 02/04/20 NP 893 +/- 159 MW-TMI-21I 08/18/20 860 +/- 159 MW-TMI-21S 02/04/20 752 +/- 147 MW-TMI-21S 02/04/20 NP 797 +/- 151 MW-TMI-21S 08/18/20 687 +/- 144 < 6.9 < 0.8 < 0.6 < 0.6 MW-TMI-21S 11/13/20 371 +/- 125 MW-TMI-22D 02/04/20 NP 1890 +/- 252 MW-TMI-22D 02/04/20 2160 +/- 277 MW-TMI-22D 08/18/20 2020 +/- 264 MW-TMI-22I 02/04/20 NP 1140 +/- 182 MW-TMI-22I 02/04/20 987 +/- 169 MW-TMI-22I 08/18/20 757 +/- 150 MW-TMI-22S 02/04/20 NP 759 +/- 148 MW-TMI-22S 02/04/20 844 +/- 155 MW-TMI-22S 08/18/20 599 +/- 137 < 7.3 < 0.8 < 0.8 < 0.6 MW-TMI-22S 11/13/20 608 +/- 144 NW-A 02/11/20 248 +/- 119 NP = Non-purge study samples B-2

TABLE B-I.1 CONCENTRATIONS OF TRITIUM, STRONTIUM, AND GROSS ALPHA IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICALGROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION Gr-A Gr-A SITE DATE H-3 Sr-89 Sr-90 (Dis) (Sus)

NW-A 08/26/20 397 +/- 131 NW-B 02/11/20 187 +/- 117 NW-B 08/26/20 370 +/- 129 < 5.4 < 0.7 < 0.8 < 1.0 NW-B 11/18/20 < 194 NW-C 02/11/20 553 +/- 134 NW-C 08/26/20 344 +/- 129 NW-CW 02/06/20 < 183 OS-14 02/05/20 < 192 OS-14 08/18/20 < 176 < 6.3 < 0.8 < 0.6 < 0.6 OS-14 11/13/20 < 189 OS-16 02/05/20 336 +/- 134 OS-16 08/18/20 248 +/- 123 < 4.5 < 0.9 < 0.4 < 1.4 OS-16 11/13/20 < 188 < 9.5 < 0.8 OS-18 08/19/20 209 +/- 118 OSF 02/06/20 368 +/- 123 OSF 08/20/20 361 +/- 132 < 9.9 < 0.8 < 1.1 < 1.0 OSF 11/17/20 282 +/- 130 RW-1 02/04/20 < 192 RW-1 08/19/20 204 +/- 119 < 6.4 < 0.8 < 0.3 < 1.0 RW-1 11/13/20 < 188 NP = Non-purge study samples B-3

TABLE B-I.2 CONCENTRATIONS OF GAMMA EMITTERS IN GROUNDWATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR 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 Cs-134 Cs-137 Ba-140 La-140 48S 08/20/20 < 14 < 34 < 1 < 1 < 3 < 1 < 2 < 2 < 3 < 1 < 1 < 14 < 5 MS-1 08/21/20 < 17 < 33 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 12 < 4 MS-2 08/19/20 < 21 < 22 < 2 < 2 < 5 < 3 < 4 < 2 < 4 < 2 < 2 < 15 < 5 MS-3 02/05/20 < 32 < 57 < 4 < 4 < 7 < 4 < 8 < 4 < 7 < 4 < 4 < 17 < 6 MS-3 08/19/20 < 17 < 18 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 14 < 5 MS-4 08/19/20 < 20 < 46 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 15 < 5 MS-5 02/05/20 < 26 < 56 < 3 < 3 < 6 < 3 < 6 < 4 < 5 < 3 < 3 < 15 < 5 MS-5 08/18/20 < 15 < 30 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 2 < 2 < 11 < 4 MS-7 08/19/20 < 21 < 16 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 15 < 5 MS-8 02/05/20 < 30 < 31 < 3 < 3 < 7 < 4 < 7 < 4 < 6 < 4 < 4 < 15 < 5 MS-8 08/18/20 < 17 < 18 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 11 < 3 MS-20 08/18/20 < 16 < 15 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 2 < 2 < 11 < 4 MS-21 08/18/20 < 17 < 17 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 13 < 5 MS-22 08/18/20 < 17 < 28 < 2 < 2 < 5 < 2 < 3 < 2 < 3 < 2 < 2 < 24 < 9 MW-1 08/21/20 < 22 < 21 < 2 < 2 < 5 < 3 < 4 < 2 < 4 < 3 < 2 < 15 < 5 B-4 MW-2 08/21/20 < 15 < 24 < 1 < 2 < 3 < 2 < 3 < 2 < 3 < 2 < 2 < 11 < 4 MW-TMI-1D 08/21/20 < 21 < 41 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 15 < 5 MW-TMI-2D 08/21/20 < 18 < 38 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 13 < 4 MW-TMI-3I 08/21/20 < 16 < 27 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 11 < 3 MW-TMI-3I DUP 08/21/20 < 20 < 37 < 2 < 2 < 6 < 2 < 5 < 3 < 4 < 3 < 2 < 15 < 5 MW-TMI-4I 08/21/20 < 21 < 47 < 2 < 2 < 5 < 2 < 5 < 3 < 4 < 2 < 2 < 15 < 5 MW-TMI-4I DUP 08/21/20 < 18 < 28 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 13 < 4 MW-TMI-4S 08/21/20 < 24 < 24 < 3 < 2 < 6 < 3 < 6 < 3 < 5 < 3 < 3 < 14 < 5 MW-TMI-6D 08/19/20 < 20 < 19 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 15 < 6 MW-TMI-6I 08/19/20 < 17 < 34 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 13 < 5 MW-TMI-7S 08/19/20 < 18 < 18 < 2 < 2 < 5 < 2 < 4 < 2 < 3 < 2 < 2 < 13 < 5 MW-TMI-8S 08/21/20 < 22 < 22 < 2 < 2 < 5 < 3 < 5 < 3 < 4 < 2 < 2 < 15 < 5 MW-TMI-9I 08/19/20 < 20 < 37 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 14 < 4 MW-TMI-10D 08/19/20 < 18 < 17 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 15 < 4 MW-TMI-10I 08/19/20 < 17 < 17 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 2 < 2 < 13 < 4 MW-TMI-10I DUP 08/19/20 < 19 < 32 < 2 < 2 < 5 < 2 < 4 < 2 < 3 < 2 < 2 < 15 < 5 MW-TMI-10S 08/19/20 < 20 < 19 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 14 < 5 MW-TMI-12S 08/19/20 < 20 < 36 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 15 < 4 MW-TMI-13I 08/21/20 < 21 < 39 < 2 < 2 < 5 < 3 < 5 < 3 < 4 < 3 < 2 < 14 < 5 MW-TMI-13I DUP 08/21/20 < 18 < 27 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 13 < 5 MW-TMI-14D 08/21/20 < 18 < 32 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 13 < 4 MW-TMI-14I 08/21/20 < 16 < 31 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 12 < 4 MW-TMI-14I DUP 08/21/20 < 15 < 27 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 2 < 2 < 12 < 4

TABLE B-I.2 CONCENTRATIONS OF GAMMA EMITTERS IN GROUNDWATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR 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 Cs-134 Cs-137 Ba-140 La-140 MW-TMI-16D 08/21/20 < 15 < 13 < 2 < 2 < 3 < 2 < 3 < 2 < 3 < 2 < 2 < 11 < 4 MW-TMI-18D 08/21/20 < 23 < 50 < 3 < 3 < 5 < 3 < 5 < 3 < 5 < 3 < 3 < 15 < 4 MW-TMI-19I 08/21/20 < 13 < 25 < 1 < 1 < 3 < 2 < 2 < 1 < 2 < 1 < 1 < 9 < 3 MW-TMI-20I 08/19/20 < 20 < 23 < 2 < 2 < 5 < 3 < 5 < 3 < 4 < 2 < 2 < 15 < 4 MW-TMI-21D 08/18/20 < 20 < 18 < 2 < 2 < 6 < 2 < 4 < 2 < 4 < 2 < 2 < 27 < 10 MW-TMI-21I 08/18/20 < 19 < 27 < 2 < 2 < 5 < 2 < 3 < 2 < 4 < 2 < 2 < 24 < 9 MW-TMI-21S 08/18/20 < 17 < 14 < 1 < 2 < 4 < 2 < 3 < 2 < 3 < 1 < 1 < 22 < 7 MW-TMI-22D 08/18/20 < 18 36 +/- 24 < 2 < 2 < 5 < 2 < 3 < 2 < 4 < 2 < 2 < 26 < 9 MW-TMI-22I 08/18/20 < 20 < 16 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 26 < 9 MW-TMI-22S 08/18/20 < 20 < 16 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 2 < 2 < 29 < 9 NW-A 08/26/20 < 15 < 26 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 2 < 2 < 13 < 4 NW-B 08/26/20 < 17 < 34 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 14 < 5 NW-C 08/26/20 < 18 < 29 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 13 < 5 OS-14 02/05/20 < 31 < 59 < 3 < 4 < 7 < 4 < 8 < 4 < 6 < 4 < 4 < 17 < 7 OS-14 08/18/20 < 18 < 17 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 13 < 4 B-5 OS-16 02/05/20 < 35 < 81 < 4 < 4 < 10 < 4 < 9 < 4 < 6 < 5 < 4 < 19 < 6 OS-16 08/18/20 < 16 < 15 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 2 < 2 < 10 < 3 OS-18 08/19/20 < 20 < 23 < 2 < 2 < 6 < 3 < 5 < 3 < 4 < 3 < 2 < 14 < 5 OSF 08/20/20 < 14 < 29 < 1 < 2 < 4 < 1 < 3 < 2 < 3 < 2 < 1 < 14 < 5 RW-1 08/19/20 < 18 < 37 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 2 < 2 < 14 < 5

TABLE B-I.3 CONCENTRATIONS OF HARD TO DETECTS IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE Am-241 Cm-242 Cm-243/244 Pu-238 Pu-239/240 U-234 U-235 U-238 Fe-55 Ni-63 MS-3 08/19/20 < 68 < 4.2 MS-5 08/18/20 < 88 < 4.9 MS-8 08/18/20 < 67 < 4.6 MW-TMI-6D 08/19/20 < 66 < 4.4 MW-TMI-6I 08/19/20 < 89 < 4.5 OS-14 08/18/20 < 107 < 4.5 OS-16 11/13/20 < 73 < 4.5 B-6

TABLE B-II.1 CONCENTRATIONS OF TRITIUM IN SURFACE WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 SW-E-1 02/05/20 < 194 SW-E-1 DUP 02/05/20 < 189 SW-E-2 02/05/20 < 192 SW-E-3 02/05/20 < 191 SW-E-3 DUP 02/05/20 < 189 B-7

TABLE B-III.1 CONCENTRATIONS OF TRITIUM IN STORM WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM - THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER + 2 SIGMA COLLECTION SITE DATES H-3 EDCB 01/30/20 - 04/01/20 < 185 EDCB 04/29/20 - 06/30/20 < 184 EDCB 07/30/20 - 10/01/20 < 177 EDCB 10/29/20 - 12/29/20 < 182 B-8

TABLE B-III.2 CONCENTRATIONS OF GAMMA EMITTERS IN STORM WATER SAMPLES COLLECTED IN THE VICINITY OF THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER + 2 SIGMA COLLECTION SITE DATES Be-7 K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 EDCB 01/30/20 - 04/01/20 < 66 < 157 < 8 < 7 < 8 < 8 < 11 < 7 < 16 < 8 < 8 < 35 < 10 EDCB 04/29/20 - 06/30/20 < 59 < 95 < 5 < 6 < 13 < 7 < 13 < 4 < 11 < 6 < 6 < 29 < 7 EDCB 07/30/20 - 10/01/20 < 14 < 15 < 2 < 2 < 3 < 2 < 3 < 2 < 3 < 2 < 2 < 7 < 2 EDCB 10/29/20 - 12/29/20 < 20 < 22 < 2 < 2 < 5 < 3 < 4 < 2 < 4 < 3 < 2 < 11 < 3 B-9

TABLE B-IV.1 CONCENTRATIONS OF TRITIUM IN PRECIPITATION WATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 TM-PR-EDCB 12/29/20 < 191 TM-PR-ESE 02/04/20 419 +/- 133 TM-PR-ESE 04/29/20 < 179 TM-PR-ESE 11/11/20 < 190 TM-PR-MS-1 02/04/20 < 192 TM-PR-MS-1 04/29/20 < 176 TM-PR-MS-1 11/11/20 < 183 TM-PR-MS-2 02/04/20 408 +/- 132 TM-PR-MS-2 04/29/20 < 198 TM-PR-MS-2 11/11/20 < 189 TM-PR-MS-4 02/04/20 < 186 TM-PR-MS-4 04/29/20 < 190 TM-PR-MS-4 11/11/20 < 188 TM-PR-MS-8 11/11/20 198 +/- 123 TM-PR-MW-22S 11/11/20 714 +/- 151 TM-PR-RW-1 11/11/20 < 189 B-10

APPENDIX C DATA TABLES COMPARISON LAB

Intentionally left blank TABLE C-I.1 CONCENTRATIONS OF TRITIUM, STRONTIUM AND GROSS ALPHA IN GROUNDWATER SPLIT SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION Gross LAB SITE DATE H-3 Sr-89 Sr-90 Alpha GEL MS-7 11/11/20 < 152 MS-20 02/04/20 420 +/- 132 MW-TMI-3I 08/21/20 387 +/- 106 < 0.8 < 0.8 < 6.6 MW-TMI-3I 11/11/20 363 +/- 109 MW-TMI-4I 08/21/20 < 159 MW-TMI-10I 08/21/20 535 +/- 132 MW-TMI-13I 08/21/20 < 141 MW-TMI-14I 02/05/20 < 159 MW-TMI-14I 08/21/20 < 146 C-1

TABLE C-I.2 CONCENTRATIONS OF GAMMA EMITTERS IN GROUNDWATER SPLIT SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB SITE PERIOD Mn-54 Fe-59 Co-58 Co-60 Zn-65 Zr-95 Nb-95 Cs-134 Cs-137 Ba-140 La-140 GEL MW-TMI-3I 08/21/20 < 2 < 4 < 2 < 2 < 4 < 3 < 2 < 2 < 2 < 9 < 3 MW-TMI-4I 08/21/20 < 2 < 4 < 1 < 2 < 4 < 3 < 2 < 2 < 2 < 8 < 3 MW-TMI-10I 08/21/20 < 2 < 4 < 2 < 2 < 5 < 3 < 2 < 2 < 2 < 9 < 4 MW-TMI-13I 08/21/20 < 2 < 3 < 2 < 2 < 4 < 3 < 2 < 2 < 2 < 9 < 3 MW-TMI-14I 08/21/20 < 2 < 4 < 2 < 2 < 4 < 3 < 2 < 2 < 2 < 9 < 4 C-2

TABLE C-I.3 CONCENTRATIONS OF HARD TO DETECTS IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Am-241 Cm-242 Cm-243/244 Pu-238 Pu-239/240 U-233/234 U-235 U-238 Fe-55 Ni-63 There were no hard to detects analyzed in 2020 C-3

TABLE C-II.1 CONCENTRATIONS OF TRITIUM IN SURFACE WATER SPLIT SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB SITE DATE H-3 GEL SW-E-1 02/05/20 < 161 SW-E-3 02/05/20 < 159 C-4

TABLE C-III.1 CONCENTRATIONS OF TRITIUM IN PRECIPITATION WATER SPLIT SAMPLES COLLECTED AS PART OF THE RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM, THREE MILE ISLAND NUCLEAR STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION LAB SITE DATES H-3 GEL TM-PR-MS-2Q 02/04/20 - 03/24/20 539 +/- 137 04/29/20 - 06/09/20 < 149 11/11/20 - 12/29/20 189 +/- 90 C-5

Intentionally left blank