Text

2020 Annual Radiological Environmental Operating Report (AREOR)
	ML21126A093
Person / Time
Site:	Byron
Issue date:	05/06/2021
From:	Kowalski J; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	BYRON 2021-0032
	Download: ML21126A093 (189)
	v • d • e

Byron Generating Station Exelon Generation _ 4450 North German Church Rd Byron. IL 61010-9794 w1*1w exeloncorp com May 6, 2021 LTR: BYRON 2021-0032 File: 1.10.0101 (1D.101) 2.12.1523 (2C.111)

United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Byron Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

2020 Annual Radiological Environmental Operating Report (AREOR)

In accordance with Technical Specification 5.6.2, "Annual Radiological Environmental Operating Report," we are submitting the Annual Radiological Environmental Operating Report (AREOR) for Byron Station, Units 1 and 2. This report is required to be submitted to the NRC by May 15th of each year and contains the results of the radiological environmental and meteorological monitoring programs. The Radioactive Effluent Release Report was submitted under separate cover.

Also included are the results of groundwater monitoring conducted in accordance with Exelon's Radiological Groundwater Protection Program (RGPP), which is a voluntary program implemented in 2006. This information is being reported in accordance with a nuclear industry initiative.

If you have any questions regarding this information, please contact Ms. Lisa Zurawski, Regulatory Assurance Manager, at (815) 406-2800.

Respectfully,

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John J. Kowalski Site Vice President Byron Generating Station JJK/AH/LZ/mf

Attachment:

AREOR Report cc: Regional Administrator - NRC Region Ill

NRC.Docket No: 50-454 50-455 BYRON NUCLEAR GENERATING STATION UNITS 1 and 2 Annual Radiological Environmental Operating Report 1 January Through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services Byron Nuclear Generating Station Byron, IL 61010 April 2021

Intentionally left blank Table Of Contents I. Summary and Conclusions .............................................................................................. 1 II. Introduction...................................................................................................................... 2 A. Objectives of the REMP....................................................................................... 2 B. Implementation of the Objectives ........................................................................ 2 III. Program Description....................................................................................................... 3 A. Sample Collection ................................................................................................ 3 B. Sample Analysis .................................................................................................. 5 C. Data Interpretation ............................................................................................... 5 D. Program Exceptions ............................................................................................ 6 E. Program Changes ............................................................................................... 8 IV. Results and Discussion ................................................................................................. 9 A. Aquatic Environment ........................................................................................... 9

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

2. Ground Water ........................................................................................... 9

3. Fish ......................................................................................................... 10

4. Sediment ................................................................................................. 10 B. Atmospheric Environment ................................................................................. 10

1. Airborne .................................................................................................. 10

a. Air Particulates ............................................................................. 10

b. Airborne Iodine............................................................................. 11

2. Terrestrial ................................................................................................ 11

a. Milk............................................................................................... 11

b. Vegetation .................................................................................... 12 C. Ambient Gamma Radiation ............................................................................... 12 D. Land Use Survey ............................................................................................... 12 E. Errata Data ........................................................................................................ 13 F. Summary of Results - Inter-laboratory Comparison Program ........................... 13

-i-

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

Analytical Methods Tables Table B-1 Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Byron Nuclear Generating Station, 2020 Table B-2 Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Byron Nuclear Generating Station, 2020 Figures Figure B-1 Inner Ring and Special Interest OSLD Locations of the Byron Nuclear Generating Station, 2020 Figure B-2 Outer Ring OSLD Locations of the Byron Nuclear Generating Station, 2020 Figure B-3 Onsite Air Sampling Locations of the Byron Nuclear Generating Station, 2020 Figure B-4 Offsite Air Sampling Locations of the Byron Nuclear Generating Station, 2020 Figure B-5 Ingestion and Waterborne Exposure Pathway Sampling Locations of the Byron Nuclear Generating Station, 2020 Appendix C Data Tables and Figures Tables Table C-I.1 Concentrations of Gross Beta in Surface Water Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020.

Table C-I.2 Concentrations of Tritium in Surface Water Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020.

Table C-I.3 Concentrations of Nickel-63 in Surface Water Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-I.4 Concentrations of Gamma Emitters in Surface Water Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 ii

Table C-II.1 Concentrations of Tritium in Ground Water Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-II.2 Concentrations of Gamma Emitters in Ground Water Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-III.1 Concentrations of Nickel-63 and Gamma Emitters in Fish Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-IV.1 Concentrations of Nickel-63 and Gamma Emitters in Sediment Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-V.1 Concentrations of Gross Beta in Air Particulate Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-V.2 Monthly and Yearly Mean Values of Gross Beta Concentrations in Air Particulate Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-V.3 Concentrations of Gamma Emitters in Air Particulate Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-VI.1 Concentrations of I-131 in Air Iodine Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-VII.1 Concentrations of I-131 in Milk Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-VII.2 Concentrations of Gamma Emitters in Milk Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-VIII.1 Concentrations of Gamma Emitters in Vegetation Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020 Table C-IX.1 Quarterly OSLD Results for Byron Nuclear Generating Station, 2020 Table C-IX.2 Mean Quarterly OSLD Results for the Inner Ring, Outer Ring, Special Interest, Other and Control Locations for Byron Nuclear Generating Station, 2020 Table C-IX.3 Summary of the Ambient Dosimetry Program for Byron Nuclear Generating Station, 2020 Figures Figure C-1 Surface Water - Gross Beta - Stations BY-12 and BY-29 (C) Collected in the Vicinity of BNGS, 2000 - 2020 Figure C-2 Surface Water - Tritium - Stations BY-12 and BY-29 (C) Collected in the Vicinity of BNGS, 2000 - 2020 Figure C-3 Ground Water - Tritium - Station BY-14-1 Collected in the Vicinity of BNGS, 2000 - 2020 iii

Figure C-4 Ground Water - Tritium - Station BY-18-1 Collected in the Vicinity of BNGS, 2010 - 2020 Figure C-5 Ground Water - Tritium - Station BY-32 Collected in the Vicinity of BNGS, 2006 - 2020 Figure C-6 Ground Water - Tritium - Station BY-35 Collected in the Vicinity of BNGS, 2006 - 2020 Figure C-7 Ground Water - Tritium - Stations BY-37 and BY-38 Collected in the Vicinity of BNGS, 2006 - 2020 Figure C-8 Air Particulate - Gross Beta - Stations BY-08 (C) and BY-21 Collected in the Vicinity of BNGS, 2000 - 2020 Figure C-9 Air Particulate - Gross Beta - Stations BY-22 and BY-23 Collected in the Vicinity of BNGS, 2000 - 2020 Figure C-10 Air Particulate - Gross Beta - Station BY-24 Collected in the Vicinity of BNGS, 2000 - 2020 Figure C-11 Air Particulate - Gross Beta - Stations BY-01 and BY-04 Collected in the Vicinity of BNGS, 2005 - 2020 Figure C-12 Air Particulate - Gross Beta - Station BY-06 Collected in the Vicinity of BNGS, 2005 - 2020 Appendix D Inter-Laboratory Comparison Program Tables Table D-1 Analytics Environmental Radioactivity Cross Check Program Teledyne Brown Engineering, 2020 Table D-2 DOEs Mixed Analyte Performance Evaluation Program (MAPEP)

Teledyne Brown Engineering, 2020 Table D-3 ERA Environmental Radioactivity Cross Check Program Teledyne Brown Engineering, 2020 Appendix E Effluent Report Appendix E-1 Data Tables and Figures Appendix F Meteorological Data Appendix G Errata data Appendix H Annual Radiological Groundwater Protection Program Report (ARGPPR) iv

I. Summary and Conclusions This report on the Radiological Environmental Monitoring Program conducted for the Byron Nuclear Generating Station by Exelon covers the period 1 January 2020 through 31 December 2020. During that time period, 1,434 analyses were performed on 1,272 samples. In assessing all the data gathered for this report and comparing these results with preoperational data, it was concluded that the operation of BNGS had no adverse radiological impact on the environment.

Surface water samples were analyzed for concentrations of gross beta, tritium, nickel-63 (Ni-63), and gamma-emitting nuclides. Ground water samples were analyzed for concentrations of tritium and gamma-emitting nuclides. Gross beta activities detected were consistent with those detected in previous years. All surface water samples analyzed for Ni-63 were less than the minimum detectable concentration. Tritium detected in downstream surface water was well below reportable limits and consistent with expected levels as a result of permitted liquid discharges.

Fish (commercially and/or recreationally important species) and sediment samples were analyzed for concentrations of Ni-63 and gamma-emitting nuclides. No fission or activation products were detected.

Air particulate samples were analyzed for concentrations of gross beta and gamma-emitting nuclides. No fission or activation products were detected.

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

Cow milk samples were analyzed for concentrations of I-131 and gamma- emitting nuclides. All I-131 results were below the minimum detectable activity. No fission or activation products were found.

Food Product samples were analyzed for concentrations of gamma-emitting nuclides. No fission or activation products were detected.

Environmental gamma radiation measurements were performed quarterly using Optically Stimulated Luminescence Dosimeters (OSLD). Beginning in 2012, Exelon changed the type of dosimetry used for the Radiological Environmental Monitoring Program (REMP). Optically Stimulated Luminescent Dosimetry were deployed and Thermoluminescent Dosimetry (TLD) were discontinued. This change may have resulted 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).

Intentionally left blank II. Introduction Byron Station, a two-unit PWR station, is located about two miles east of the Rock River and approximately three miles southwest of Byron in Ogle County, Illinois.

The reactors are designed to have capacities of 1,268 and 1,241 MW gross, respectively. Unit One loaded fuel in November 1984 and went online February 2, 1985. Unit Two went online January 9, 1987. The station has been designed to keep releases to the environment at levels below those specified in the codes of federal regulations.

This report covers those analyses performed by Teledyne Brown Engineering (TBE) and Landauer 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. Provide data on measurable levels of radiation and radioactive materials in the site environs.

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

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

1. Identifying significant exposure pathways

2. Establishing baseline radiological data of media within those pathways

3. Continuously monitoring those media before and during Station operation to assess Station radiological effects (if any) on man and the environment III. Program Description A. Sample Collection Samples for the BNGS REMP were collected for Exelon Nuclear by Environmental Inc. (Midwest Labs). This section describes the general collection methods used by Environmental Inc. to obtain environmental samples for the BNGS REMP in 2020. Sample locations and descriptions can be found in Table B-1 and Figures B-1 through B-5, Appendix B.

Aquatic Environment The aquatic environment was evaluated by performing radiological analyses on samples of surface water, ground water, fish and sediment.

Two gallon water samples were collected weekly from two surface water locations (BY-12 and BY-29 [Control location]) and quarterly from six ground water locations (BY-14-1, BY-18-1, BY-32, BY-35, BY-37 and BY-38). All samples were collected in new unused plastic bottles, which were rinsed with source water prior to collection. Fish samples comprising the flesh of silver redhorse, shorthead redhorse, freshwater drum, common carp and channel catfish were collected semiannually at two locations, BY-29 (control) and BY-31. Sediment samples composed of recently deposited substrate were collected at two locations semiannually, BY-12 and BY-34 (control).

Atmospheric Environment The atmospheric environment was evaluated by performing radiological analyses on samples of air particulate, and airborne iodine. Airborne iodine and particulate samples were collected and analyzed weekly at eight locations (BY-01, BY-04, BY-06, BY-08, BY-21, BY-22, BY-23 and BY-24).

The control location was BY-08. Airborne iodine and air particulate samples were obtained at each location, using a vacuum pump with charcoal and glass fiber filters attached. The pumps ran continuously and sampled air at the rate of approximately one cubic foot per minute. The air filters and air iodine samples 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 products. Milk samples were collected monthly from January through April and November through December, and biweekly May through October. The control location was BY-26-2 and the indicator location was BY-20-1. 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 annually in August and September at five locations (BY-Control, BY-Quad 1, BY-Quad 2, BY-Quad 3 and BY-Quad 4). Various types of samples were collected and 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 Thermoluminescent 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).

In recent years, the industry recognized the need for a standard method of reporting environmental dosimetry results. In 2020, Exelon began assessing facility-related dose in accordance with ANSI N13.37-2014, Environmental Dosimetry - Criteria for System Design and Implementation.

This standard is applicable to passive environmental dosimetry systems used to monitor areas surrounding radiological facilities to assess potential facility-related radiation doses and to verify compliance with public dose limits. Such environmental dosimetry systems include dosimeters which accumulate radiation dose and any readout device required to process the dosimeters. Passive dosimeters include optically stimulated luminescence (OSL) dosimeters which are deployed at field locations around a facility and exchanged periodically (e.g., quarterly). Facility-related dose is calculated using a statistical model that uses baseline historical data and accounts for transit and deploy dose. In 2020, none of the Byron Station field locations listed in this report exhibited facility-related dose as calculated in accordance with this standard.

Each location consisted of 2 OSLD sets. The OSLDs were exchanged quarterly and sent to Landauer for analysis. The OSLDs were placed at locations on and around the BNGS Station site as follows:

An inner ring consisting of 16 locations (BY-101, BY-102, BY-103, BY-104, BY-105, BY-106, BY-107, BY-108, BY-109, BY-110, BY-111, BY-112, BY-113, BY-114, BY-115 and BY-116) 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 BNGS releases.

An outer ring consisting of 16 locations (BY-201, BY-202, BY-203, BY-204, BY-205, BY-206, BY-207, BY-208, BY-209, BY-210, BY-211, BY-212, BY-213, BY-214, BY-215 and BY-216) extending to approximately 5 miles from the site designed to measure possible exposures to close-in population.

A special interest set consisting of seven locations (BY-301-1, BY-301-2, BY-309-1, BY-309-2, BY-309-3, BY-309-4, and BY-314-2) to measure possible exposures from on-site storage facilities.

An other set consisting of seven locations (BY-01, BY-04, BY-06, BY-21, BY-22, BY-23 and BY-24) at locations where air samplers are present.

The balance of one location (BY-08) representing the control area.

The specific OSLD 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-22 1/2 degree sectors around the site, where estimated annual dose from BNGS, 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 if applicable.

Two OSLDs were placed at each location above ground level. The OSLDs were exchanged quarterly and sent to Landauer for analysis.

B. Sample Analysis This section describes the general analytical methodologies used by TBE to analyze the environmental samples for radioactivity for the BNGS REMP in 2020. The analytical procedures used by the laboratory are listed in Table B-2.

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

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

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

3. Concentrations of tritium in ground and surface water

4. Concentrations of iodine-131 in air and milk

5. Concentrations of nickel-63 in surface water, fish and sediment

6. Ambient gamma radiation levels at various site environs C. Data Interpretation The radiological and direct radiation data collected prior to Byron Nuclear Generating Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, Byron Nuclear Generating Station was considered operational at initial criticality. In addition, data were compared to previous years' operational data for consistency and trending. Several factors were important in the interpretation of the data:

1. Lower Limit of Detection and Minimum Detectable Concentration The lower limit of detection (LLD) 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 BNGS 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, effecting 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 water, ground water, milk and vegetation, twelve nuclides, Mn-54, Co-58, Fe-59, Co-60, Zn-65, Nb-95, Zr-95, I-131, Cs-134, Cs-137, Ba-140 and La-140 were reported.

For fish, sediment, and air particulates, eleven nuclides, 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.

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 BNGS REMP had a sample recovery rate in excess of 99%.

Sample anomalies and missed samples are listed in the tables below:

TABLE D-1 LISTING OF SAMPLE ANOMALIES Sample Location Collection Type Code Date Reason Filter darker than usual, possibly due to the pump degrading; pump AP BY-01 01/28/20 exchanged with 186 Timer indicates approximately 4 hrs less than expected for the AP/AI BY-21 02/25/20 7-day collection - power failure Timer indicates approximately 8 hrs less than expected for the AP/AI BY-21 03/03/20 7-day collection due to power fluctuation - changed out 3/5 Total run time 124 hrs during 7-day period due to timer failure and AP/AI BY-21 03/10/20 power outage caused by heavy winds; 3/17 indicated normal run time of 167.8 hrs Total run time 149 hrs during 7-day period due to power outage AP/AI BY-23 03/10/20 caused by heavy winds; next week indicated normal runtime of 167.8 hrs Missing approximately 24 hrs due to extensive power failure caused AP/AI ALL 03/31/20 by a tornado 1st Quarter composite > LLD; positive result due to many liquid SW BY-12 04/15/20 releases performed in support of B1R23 Timer indicates approximately 5 hrs less than expected due to a power failure; pump found not running, was reset and restarted.

AP/AI BY-21 05/05/20 NOTE: during the 05/12/20 collection, timer indicated 167.9 hrs -

normal reading for the collection period OSLD BY-309-3 07/01/20 Both OSLD samples found on the ground AP/AI BY-01 08/11/20 Lower reading of 149.4 hrs during a 7-day collection due to storms Timer indicates 4.5 hrs less than expected due to power outage AP/AI BY-06 08/11/20 caused by storms Lower reading of 149.1 hrs during a 7-day period of collection; power AP/AI BY-24 08/11/20 outage at plant due to storms Lower reading of 121.4 hrs during a 7-day collection possibly caused AP/AI BY-24 08/18/20 by power outage; timer will be changed during next collection Lower reading of 152.7 hrs during a 7 day collection caused by AP/AI BY-21 09/29/20 power outage Lower reading of 158.5. NOTE: timer the week after indicated a AP/AI BY-21 10/06/21 normal reading Timer indicated 8 hrs less than expected due to widespread power AP/AI BY-01 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

Timer indicated 4.3 hrs less than expected due to widespread power AP/AI BY-04 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

Timer indicated 9 hrs less than expected due to widespread power AP/AI BY-06 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

TABLE D-1 LISTING OF SAMPLE ANOMALIES (contd)

Sample Location Collection Type Code Date Reason Timer indicated 12 hrs less than expected due to widespread power AP/AI BY-08 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

Timer indicated 26 hrs less than expected due to widespread power AP/AI BY-21 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

Timer indicated 4.4 hrs less than expected due to widespread power AP/AI BY-22 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

Timer indicated 4.3 hrs less than expected due to widespread power AP/AI BY-24 11/17/21 failure caused by heavy winds. NOTE: during the 11/24 collection, the timer indicated correct hrs.

Lower reading of 109 hrs during a 7-day collection period due to a AP/AI BY-21 12/08/20 power outage. NOTE: during the collection of 12/15, the timer reading correct hrs.

TABLE D-2 LISTING OF MISSED SAMPLES Sample Location Collection Type Code Date Reason BY-104-1 BY-107-1 OSLD BY-109-1 04/01/20 OSLDs missing in quarterly exchange due to tornado in area BY-206-2 BY-207-2 OSLD BY-207-2 07/20/20 One OSLD missing during exchange BY-216-1 OSLD 12/01/20 OSLDs missing in quarterly exchange due to weather BY-314-2 SW BY-29 12/29/20 Could not collect sample due to frozen river 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 program changes in 2020.

IV. Results and Discussion A. Aquatic Environment

1. Surface Water Samples were taken weekly and composited monthly at two locations (BY-12 and BY-29). Of these locations only BY-12 located downstream, could be affected by Byron Nuclear Generating Stations effluent releases. The following analyses were performed:

Gross Beta Samples from both locations were analyzed for concentrations of gross beta (Table C-I.1, Appendix C). The values ranged from 2.5 to 7.7 pCi/L. Concentrations detected were consistent with those detected in previous years (Figure C-1, Appendix C).

Tritium Quarterly composites of weekly collections were analyzed for tritium activity (Table C-I.2, Appendix C). Tritium was detected in four samples. (Figure C-2, Appendix C). The concentrations ranged from 419 to 4,700 pCi/L. Tritium detected in downstream surface water was well below reportable limits and consistent with expected levels as a result of permitted liquid discharges.

Nickel Samples from both locations were analyzed for concentration of Ni-63 (Table C-I.3, Appendix C). All results were less than the minimum detectable concentration.

Gamma Spectrometry Samples from both locations were analyzed for gamma-emitting nuclides (Table C-I.4, Appendix C). No nuclides were detected, and all required LLDs were met.

2. Ground Water Quarterly grab samples were collected at six locations (BY-14-1, BY-18-1, BY-32, BY-35, BY-37 and BY-38). These locations could be affected by Byron Nuclear Generating Stations effluent releases.

The following analyses were performed:

Tritium Quarterly grab samples from the locations were analyzed for tritium activity (Table C-II.1, Appendix C). No tritium was detected, and the required LLD was met (Figures C-3 through C-7, Appendix C).

Gamma Spectrometry Samples from all locations were analyzed for gamma-emitting nuclides (Table C-II.2 Appendix C). No nuclides were detected, and all required LLDs were met.

3. Fish Fish samples comprised of quillback, shorthead redhorse, smallmouth bass, golden redhorse, silver redhorse, and common carp were collected at two locations (BY-29 and BY-31) semiannually. Location BY-31 could be affected by Byron Nuclear Generating Stations effluent releases. The following analyses were performed:

Nickel The edible portion of fish samples from both locations was analyzed for Ni-63 (Table C-III.1, Appendix C). Nickel-63 was not detected and the required LLD was met.

Gamma Spectrometry The edible portion of fish samples from both locations was analyzed for gamma-emitting nuclides (Table C-III.1, Appendix C). No nuclides were detected, and all required LLDs were met.

4. Sediment Aquatic sediment samples were collected at two locations (BY-12 and BY-34) semiannually. BY-12, located downstream, could be affected by Byron Nuclear Generating Stations effluent releases. The following analyses were performed:

Nickel Sediment samples from both locations were analyzed for Ni-63 (Table C-IV.1, Appendix C). Ni-63 was not detected and the required LLD was met.

Gamma Spectrometry Sediment samples from both locations were analyzed for gamma-emitting nuclides (Table C-IV.1, Appendix C). No nuclides were detected, and all required LLDs were met.

B. Atmospheric Environment

1. Airborne

a. Air Particulates Continuous air particulate samples were collected from eight locations on a weekly basis. The eight locations were separated into three groups: Nearsite samplers within 4 km of the site (BY-21, BY-22, BY-23 and BY-24), Far Field samplers between 4 and 10 km of the site (BY-01, BY-04 and BY-06) and the Control sampler between 10 and 30 km from the site (BY-08). The following analyses were performed:

Gross Beta Weekly samples were analyzed for concentrations of beta emitters (Table C-V.1 and C-V.2, Appendix C). Detectable gross beta activity was observed at all locations. Comparison of results among the three groups aid in determining the effects, if any, resulting from the operation of BNGS.

The results from the Nearsite locations (Group I) ranged from 5 to 33E-3 pCi/m3 with a mean of 16E-3 pCi/m3. The results from the Far Field locations (Group II) ranged from 6 to 32E-3 pCi/m3 with a mean of 16E-3 pCi/m3. The results from the Control location (Group III) ranged from 6 to 34E-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 BNGS. In addition, a comparison of the weekly mean values for 2020 indicate no notable differences among the three groups.

(Figures C-8 through C-12, Appendix C)

Gamma Spectrometry Weekly samples were composited quarterly and analyzed for gamma-emitting nuclides (Table C-V.3, Appendix C). No nuclides were detected, and all required LLDs were met.

b. Airborne Iodine Continuous air samples were collected from eight locations (BY-01, BY-04, BY-06, BY-08, BY-21, BY-22, BY-23 and BY-24) and analyzed weekly for I-131 (Table C-VI.1, Appendix C). All results were less than the minimum detectable concentration for I-131.

2. Terrestrial

a. Milk Samples were collected from two locations (BY-20-1 and BY-26-2) monthly from January to April and November through December, and biweekly May through October. The following analyses were performed:

Iodine-131 Milk samples from all locations were analyzed for concentrations of I-131 (Table C-VII.1, Appendix C). No nuclides were detected, and all required LLDs were met.

Gamma Spectrometry Each milk sample was analyzed for concentrations of gamma-emitting nuclides (Table C-VII.2, Appendix C). No nuclides were detected, and all required LLDs were met.

b. Vegetation Vegetation samples were collected at five locations (BY-Control, BY-Quad 1, BY-Quad 2, BY-Quad 3 and BY-Quad 4). Four locations (BY-Quad 1, BY-Quad 2, BY-Quad 3 and BY-Quad 4) could be affected by Byron Nuclear Generating Stations effluent releases. The following analysis was performed:

Gamma Spectrometry Samples from all locations were analyzed for gamma- emitting nuclides (Table C-VIII.1, Appendix C). No nuclides were detected, and all required LLDs were met.

C. Ambient Gamma Radiation Ambient gamma radiation levels were measured utilizing OSLDs.

Ninety-one OSLD locations were established around the site. Results of OSLD measurements are listed in Tables C-IX.1 to C-IX.3, Appendix C.

All OSLD measurements were below 28 mR/standard quarter, with a range of 15 to 27 mR/standard quarter. A comparison of the Inner Ring, Outer Ring, Special Interest, Other and Control Location data indicate that the ambient gamma radiation levels were comparable among the groups.

D. Land Use Survey A Land Use Survey conducted during September 2020 around the Byron Nuclear Generating Station (BNGS) was performed by Environmental Inc.

(Midwest Labs) for Exelon Nuclear to comply with the Byron Nuclear Generating Stations Offsite Dose Calculation Manual. The purpose of the survey was to document the nearest resident, livestock, and milk producing animals in each of the sixteen 22 1/2 degree sectors. The results of this survey are summarized as follows:

Distance in Miles from the BNGS Vent Stacks Residence Livestock Milk Farm Sector Miles Miles Miles A N 1.2 5.9 -

B NNE 1.6 6.2 -

C NE 1.1 2.0 -

D ENE 1.4 3.7 -

E E 1.0 4.2 -

F ESE 1.5 1.5 -

G SE 1.7 3.5 -

H SSE 0.7 3.3 -

J S 0.6 0.7 -

K SSW 0.7 0.7 -

L SW 0.8 2.0 -

M WSW(a) 1.6 0.8 4.5 N W 1.8 3.2 -

P WNW 1.6 1.6 11.5 Q NW 0.8 1.5 -

R NNW 0.9 1.4 -

(a) Denotes the nearest industrial facility located at 1.5 miles E. Errata Data Errata data in Appendix C includes erroneous sampling locations for vegetation and for gaseous release volume calculations.

F. Summary of Results - Inter-Laboratory Comparison Program The TBE Laboratory analyzed Performance Evaluation (PE) samples of air particulate, air iodine (charcoal), milk, soil, vegetation and water (including fish) matrices (Appendix D). The PE sample matrices were chosen based on the types of samples submitted to the primary laboratory for analysis.

The selected parameters for the PE samples are based on the appropriate matrices, methodologies and geometries, which include geometries that are comparable. The PE samples, supplied by Analytics Inc., Environmental Resource Associates (ERA) and DOEs Mixed Analyte Performance Program (MAPEP) were evaluated against the following pre-set acceptance criteria:

1. Analytics Evaluation Criteria Analytics evaluation report provides a ratio of laboratory results 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. MAPEP defines three levels of performance:

Acceptable (flag = A) - result within +/- 20% of the reference value

Acceptable with Warning (flag = W) - result falls in the +/- 20% to

+/- 30% of the reference value

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

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

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 20-13)

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)

The Inter-Laboratory Comparison Program provides evidence of in control counting systems and methods, and that the laboratories are producing accurate and reliable data.

APPENDIX A RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT

SUMMARY

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

SUMMARY

FOR BYRON NUCLEAR GENERATING STATION, 2020 NAME OF FACILITY: BYRON NUCLEAR GENERATING STATION DOCKET NUMBER: 50-454 & 50-455 LOCATION OF FACILITY: BYRON, IL REPORTING PERIOD: 2020 INDICATOR CONTROL REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) NUMBER OF MEDIUM OR TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE PATHWAY SAMPLED ANALYSIS ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED (Uint of Measurement) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS SURFACE WATER GR-B 24 4 4.9 5 5 BY-29 CONTROL 0 (PCI/LITER) (11/12) (12/12) (12/12) BYRON - UPSTREAM 3.2 - 7.7 2.5 - 6.8 2.5 - 6.8 3.0 MILES N OF SITE H-3 8 200 2037 <LLD 2037 BY-12 INDICATOR 0 (4/4) (4/4) OREGON POOL OF ROCK RIVER - DOWNSTREAM 419 - 4700 419 - 4700 4.5 MILES SSW OF SITE NI-63 24 30 <LLD <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 A-1 ZN-65 30 <LLD <LLD - 0 NB-95 15 <LLD <LLD - 0 ZR-95 30 <LLD <LLD - 0 I-131 15 <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 GROUND WATER H-3 24 200 <LLD NA - 0 (PCI/LITER)

GAMMA 24 MN-54 15 <LLD NA - 0 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 I-131 15 <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 (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 BYRON NUCLEAR GENERATING STATION, 2020 NAME OF FACILITY: BYRON NUCLEAR GENERATING STATION DOCKET NUMBER: 50-454 & 50-455 LOCATION OF FACILITY: BYRON, IL REPORTING PERIOD: 2020 INDICATOR CONTROL REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) NUMBER OF MEDIUM OR TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE PATHWAY SAMPLED ANALYSIS ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED (Uint of Measurement) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS FISH NI-63 8 260 <LLD <LLD - 0 (PCI/LITER) GAMMA 8 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 NB-95 NA <LLD <LLD - 0 ZR-95 NA <LLD <LLD - 0 CS-134 130 <LLD <LLD - 0 CS-137 150 <LLD <LLD - 0 BA-140 NA <LLD <LLD - 0 LA-140 NA <LLD <LLD - 0 SEDIMENT NI-63 4 260 <LLD <LLD - 0 A-2 (PCI/KG DRY) GAMMA 4 -

MN-54 NA <LLD <LLD 0 CO-58 NA <LLD <LLD - 0 FE-59 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 ZN-65 NA <LLD <LLD - 0 NB-95 NA <LLD <LLD - 0 ZR-95 NA <LLD <LLD - 0 CS-134 150 <LLD <LLD - 0 CS-137 180 <LLD <LLD - 0 BA-140 NA <LLD <LLD - 0 LA-140 NA <LLD <LLD - 0 AIR PARTICULATE GR-B 416 10 16 15 17 BY-06 INDICATOR 0 (E-3 PCI/CU.METER) (363/364) (52/52) (52/52) OREGON 5 - 33 6 - 34 9 - 32 4.7 MILES SSW OF SITE GAMMA 32 MN-54 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 FE-59 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 ZN-65 NA <LLD <LLD - 0 NB-95 NA <LLD <LLD - 0 ZR-95 NA <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 CS-137 18 <LLD <LLD - 0 BA-140 NA <LLD <LLD - 0 LA-140 NA <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 BYRON NUCLEAR GENERATING STATION, 2020 NAME OF FACILITY: BYRON NUCLEAR GENERATING STATION DOCKET NUMBER: 50-454 & 50-455 LOCATION OF FACILITY: BYRON, IL REPORTING PERIOD: 2020 INDICATOR CONTROL REQUIRED LOCATIONS LOCATION LOCATION WITH HIGHEST ANNUAL MEAN (M) NUMBER OF MEDIUM OR TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE PATHWAY SAMPLED ANALYSIS ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED (Uint of Measurement) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS AIR IODINE GAMMA 416 (E-3 PCI/CU.METER) I-131 (GELI) 70 <LLD <LLD - 0 MILK I-131 (LOW LVL) 38 1 <LLD <LLD - 0 (PCI/LITER)

GAMMA MN-54 38 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 FE-59 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 ZN-65 NA <LLD <LLD - 0 NB-95 NA <LLD <LLD - 0 ZR-95 NA <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 A-3 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 VEGETATION GAMMA 10 (PCI/KG WET) MN-54 NA <LLD <LLD - 0 CO-58 NA <LLD <LLD - 0 FE-59 NA <LLD <LLD - 0 CO-60 NA <LLD <LLD - 0 ZN-65 NA <LLD <LLD - 0 NB-95 NA <LLD <LLD - 0 ZR-95 NA <LLD <LLD - 0 I-131 60 <LLD <LLD - 0 CS-134 60 <LLD <LLD - 0 CS-137 80 <LLD <LLD - 0 BA-140 NA <LLD <LLD - 0 LA-140 NA <LLD <LLD -

DIRECT RADIATION OSLD-QUARTERLY 332 NA 21.7 17.9 25.1 BY-216-1 INDICATOR 0 (MILLIREM/QTR.) (328/328) (4/4) (4/4) 15 - 26 17 - 19 23 - 27 4.6 MILES NNW (M) The Mean Values are calculated using the positive values. (F) Fraction of detectable measurement are indicated in parentheses.

Intentionally left blank APPENDIX B LOCATION DESIGNATION, DISTANCE & DIRECTION, AND SAMPLE COLLECTION & ANALYTICAL METHODS

Intentionally Left Blank TABLE B-1: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Byron Nuclear Generating Station, 2020 Location Location Description Distance & Direction From Site A. Surface Water BY-12 Oregon Pool of Rock River, Downstream 4.5 miles SSW BY-29 Byron, Upstream (control) 3.0 miles N B. Ground/Well Water BY-14-1 3200 North German Church Road 1.0 miles SSE BY-18-1 Calhoun 0.7 miles SSW BY-32 Krueger Well 1.9 miles W BY-35 Vancko Well 1.9 miles WNW BY-37 Cavage Well 2.0 miles WNW BY-38 Steve Storz Well 2.0 miles WNW C. Milk BY-20-1 Ron Snodgrass Farm 4.8 miles WSW BY-26-2 Joseph Akins Farm (control) 12.2 miles WNW D. Air Particulates / Air Iodine BY-01 Byron 3.0 miles N BY-04 Paynes Point 5.0 miles SE BY-06 Oregon 4.7 miles SSW BY-08 Leaf River (control) 7.0 miles WNW BY-21 Byron Nearsite North 0.3 miles N BY-22 Byron Nearsite Southeast 0.4 miles SE BY-23 Byron Nearsite South 0.6 miles S BY-24 Byron Nearsite Southwest 0.7 miles SW E. Fish BY-29 Byron, Upstream (control) 3.0 miles N BY-31 Byron, Discharge 2.6 miles WNW F. Sediment BY-12 Oregon Pool of Rock River, Downstream 4.6 miles SSW BY-34 Rock River, Upstream of Discharge (control) 2.6 miles WNW G. Vegetation Quadrant 1 5186 Cox Road, Stillman Valley 4.6 miles E Quadrant 2 6970 Linden Wood Road, Stillman Valley 4.9 miles SE Quadrant 3 555 Park Rd, Oregon 3.7 miles SW Quadrant 4 4615 N Razorville Road., Byron 2.7 miles SW Control 2327 Route 251, Rochelle 20.7 miles SE B-1

TABLE B-1: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Byron Nuclear Generating Station, 2020 Location Location Description Distance & Direction From Site H. Environmental Dosimetry - OSLD Inner Ring BY-101-1 and -2 0.3 miles N BY-102-1 1.0 miles NNE BY-102-2 1.0 miles NNE BY-103-1 and -2 1.7 miles NE BY-103-3 0.4 miles NE BY-104-1 and -2 1.4 miles ENE BY-104-3 0.3 miles ENE BY-105-1 and -2 1.3 miles E BY-106-1 and -2 1.4 miles ESE BY-107-1 and -2 1.4 miles SE BY-107-3 0.4 miles SE BY-108-1 0.7 miles SSE BY-108-2 0.6 miles SSE BY-109-1 and -2 0.6 miles S BY-110-1 and -2 0.7 miles SSW BY-111-3 0.8 miles SW BY-111-4 0.9 miles SW BY-112-3 and -4 0.8 miles WSW BY-113-1 and -2 0.7 miles W BY-114-1 and -2 0.8 miles WNW BY-115-1 and -2 1.0 miles NW BY-116-1 and -2 1.4 miles NNW BY-116-3 0.9 miles NNW Outer Ring BY-201-3 4.4 miles N BY-201-4 4.4 miles N BY-202-1 4.4 miles NNE BY-202-2 4.8 miles NNE BY-203-1 4.8 miles NE BY-203-2 4.7 miles NE BY-204-1 4.1 miles ENE BY-204-2 4.0 miles ENE BY-205-1 and -2 3.8 miles E BY-206-1 4.0 miles ESE BY-206-2 4.3 miles ESE BY-207-1 4.2 miles SE BY-207-2 3.9 miles SE BY-208-1 4.0 miles SSE BY-208-2 3.8 miles SSE BY-209-1 and -4 4.0 miles S BY-210-3 and -4 3.9 miles SSW BY-211-1 and -4 4.9 miles SW BY-212-1 and -4 4.7 miles WSW BY-213-1 4.7 miles W BY-213-4 4.7 miles W BY-214-1 4.7 miles WNW BY-214-4 4.6 miles WNW BY-215-1 4.2 miles NW BY-215-4 4.2 miles NW BY-216-1 4.5 miles NNW BY-216-2 4.7 miles NNW B-2

TABLE B-1: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, Byron Nuclear Generating Station, 2020 Location Location Description Distance & Direction From Site Special Interest BY-301-1 0.3 miles N BY-301-2 0.2 miles N BY-309-1 0.3 miles S BY-309-2 0.4 miles S BY-309-3 0.4 miles S BY-309-4 0.4 miles SSW BY-314-2 0.3 miles WNW Other BY-01-1 and -2 3.0 miles N BY-04-1 and -2 5.0 miles SE BY-06-1 and -2 4.7 miles SSW BY-21-1 and -2 0.3 miles N BY-22-1 and -2 0.4 miles SE BY-23-1 and -2 0.6 miles S BY-24-1 and -2 0.7 miles SW Control BY-08-1 and -2 7.0 miles WNW B-3

TABLE B-2: Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, Byron Nuclear Generating Station, 2020 Sample Analysis Sampling Method Analytical Procedure Number Medium Monthly composite from Surface Water Gamma Spectroscopy TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis weekly grab samples.

Monthly composite from TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Surface Water Gross Beta weekly grab samples. Various Matrices Monthly composite from Surface Water Nickel-63 TBE, TBE-2013 Radionickel Activity in Various Matrices weekly grab samples.

Quarterly composite from TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Surface Water Tritium weekly grab samples. Scintillation Ground Water Gamma Spectroscopy Quarterly grab samples. TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Ground Water Tritium Quarterly grab samples.

Scintillation Semi-annual samples Fish Gamma Spectroscopy collected via electroshocking TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis or other techniques Semi-annual samples Fish Nickel-63 collected via electroshocking TBE, TBE-2013 Radionickel Activity in Various Matrices or other techniques Sediment Gamma Spectroscopy Semi-annual grab samples TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Sediment Nickel-63 Semi-annual grab samples TBE, TBE-2013 Radionickel Activity in Various Matrices One-week composite of TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Air Particulates Gross Beta continuous air sampling Various Matrices through glass fiber filter paper Quarterly composite of Air Particulates Gamma Spectroscopy continuous air sapling TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis through glass fiber filter paper One-week composite of Air Iodine Gamma Spectroscopy continuous air sampling TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis through charcoal filter Bi-weekly grab sample when Milk I-131 cows are on pasture. TBE, TBE-2012 Radioiodine in Various Matrices Monthly all other times Bi-weekly grab sample when Milk Gamma Spectroscopy cows are on pasture. TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Monthly all other times Vegetation Gamma Spectroscopy Annual grab samples. TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Optically Stimulated Quarterly OSLDs comprised OSLD Luminescence of two Al2O3:C Landauer Landauer Incorporated Dosimetry Incorporated elements.

B-4

Figure B-1 Inner Ring and Special Interest OSLD Locations of the Byron Nuclear Generating Station, 2020 B-5

Figure B-2 Outer Ring OSLD Locations of the Byron Nuclear Generating Station, 2020 B-6

Figure B-3 Onsite Air Sampling Locations of the Byron Nuclear Generating Station, 2020 B-7

Figure B-4 Offsite Air Sampling Locations of the Byron Nuclear Generating Station, 2020 B-8

Figure B-5 Ingestion and Waterborne Exposure Pathway Sampling Locations of the Byron Nuclear Generating Station, 2020 B-9

Intentionally left blank APPENDIX C DATA TABLES AND FIGURES

Intentionally left blank Table C-I.1 CONCENTRATIONS OF GROSS BETA IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD BY-12 BY-29 01/07/20 - 01/28/20 5.4 +/- 2.2 3.4 +/- 2.0 02/04/20 - 02/25/20 4.0 +/- 2.1 5.4 +/- 2.2 03/03/20 - 03/31/20 7.7 +/- 2.5 4.7 +/- 2.2 04/07/20 - 04/28/20 4.8 +/- 2.1 5.3 +/- 2.0 05/05/20 - 05/26/20 5.0 +/- 2.7 6.8 +/- 2.9 06/02/20 - 06/30/20 3.6 +/- 1.8 2.5 +/- 1.7 07/07/20 - 07/28/20 4.9 +/- 2.1 5.2 +/- 2.1 08/04/20 - 08/25/20 < 4.0 4.9 +/- 2.8 09/01/20 - 09/29/20 4.0 +/- 2.2 6.1 +/- 2.4 10/06/20 - 10/27/20 3.2 +/- 2.0 3.5 +/- 2.0 11/03/20 - 11/24/20 7.1 +/- 2.4 6.5 +/- 2.2 12/01/20 - 12/22/20 4.2 +/- 2.2 5.2 +/- 2.3 MEAN +/- 2 STD DEV 4.9 +/- 2.8 5.0 +/- 2.6 Table C-I.2 CONCENTRATIONS OF TRITIUM IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD BY-12 BY-29 01/07/20 - 03/31/20 4700 +/- 537 < 197 04/07/20 - 06/30/20 960 +/- 170 < 185 07/07/20 - 09/29/20 2070 +/- 275 < 189 10/06/20 - 12/22/20 419 +/- 131 < 184 MEAN +/- 2 STD DEV 2037 +/- 3807 -

Table C-I.3 CONCENTRATIONS OF NI-63 IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD BY-12 BY-29 01/07/20 - 01/28/20 < 21 < 22 02/04/20 - 02/25/20 < 23 < 23 03/03/20 - 03/31/20 < 22 < 22 04/07/20 - 04/28/20 < 18 < 18 05/05/20 - 05/26/20 < 25 < 28 06/02/20 - 06/30/20 < 28 < 24 07/07/20 - 07/28/20 < 20 < 19 08/04/20 - 08/25/20 < 28 < 26 09/01/20 - 09/29/20 < 17 < 17 10/06/20 - 10/27/20 < 25 < 24 11/03/20 - 11/24/20 < 21 < 20 12/01/20 - 12/22/20 < 21 < 20 MEAN - -

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

Table C-I.4 CONCENTRATIONS OF GAMMA EMITTERS IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 BY-12 01/07/20 - 01/28/20 < 5 < 5 < 11 < 5 < 11 < 6 < 9 < 14 < 5 < 5 < 32 < 12 02/04/20 - 02/25/20 < 3 < 4 < 10 < 5 < 9 < 5 < 8 < 14 < 5 < 5 < 32 < 10 03/03/20 - 03/31/20 < 4 < 4 < 9 < 4 < 10 < 5 < 8 < 15 < 5 < 4 < 34 < 10 04/07/20 - 04/28/20 < 4 < 5 < 10 < 5 < 10 < 5 < 8 < 12 < 4 < 5 < 29 < 9 05/05/20 - 05/26/20 < 5 < 5 < 11 < 6 < 9 < 6 < 8 < 13 < 6 < 6 < 37 < 8 06/02/20 - 06/30/20 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 11 < 2 < 2 < 19 < 6 07/07/20 - 07/28/20 < 2 < 3 < 6 < 3 < 5 < 3 < 4 < 7 < 3 < 3 < 17 < 6 08/04/20 - 08/25/20 < 2 < 2 < 4 < 2 < 3 < 2 < 4 < 10 < 2 < 2 < 18 < 6 09/01/20 - 09/29/20 < 3 < 4 < 8 < 4 < 6 < 4 < 6 < 14 < 4 < 4 < 29 < 8 10/06/20 - 10/27/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 9 < 2 < 2 < 17 < 6 11/03/20 - 11/24/20 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 8 < 2 < 2 < 16 < 5 12/01/20 - 12/29/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 11 < 2 < 2 < 18 < 7 MEAN - - - - - - - - - - - -

C-2 BY-29 01/07/20 - 01/28/20 < 4 < 5 < 9 < 4 < 9 < 5 < 7 < 13 < 5 < 4 < 29 < 10 02/04/20 - 02/25/20 < 4 < 5 < 9 < 5 < 10 < 5 < 8 < 13 < 4 < 5 < 31 < 9 03/03/20 - 03/31/20 < 3 < 3 < 6 < 2 < 5 < 3 < 5 < 10 < 3 < 3 < 22 < 6 04/07/20 - 04/28/20 < 4 < 4 < 8 < 4 < 6 < 3 < 6 < 10 < 4 < 3 < 22 < 8 05/05/20 - 05/26/20 < 4 < 5 < 10 < 5 < 9 < 4 < 8 < 14 < 5 < 5 < 29 < 9 06/02/20 - 06/30/20 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 10 < 2 < 2 < 17 < 5 07/07/20 - 07/28/20 < 3 < 3 < 6 < 3 < 5 < 3 < 5 < 8 < 3 < 3 < 18 < 5 08/04/20 - 08/25/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 11 < 2 < 2 < 19 < 7 09/01/20 - 09/29/20 < 3 < 4 < 8 < 4 < 6 < 4 < 6 < 14 < 3 < 3 < 28 < 9 10/06/20 - 10/27/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 8 < 2 < 2 < 17 < 6 11/03/20 - 11/24/20 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 7 < 2 < 2 < 14 < 5 12/01/20 - 12/22/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 13 < 2 < 2 < 22 < 7 MEAN - - - - - - - - - - - -

Table C-II.1 CONCENTRATIONS OF TRITIUM IN GROUND WATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD BY-14-1 BY-18-1 BY-32 BY-35 BY-37 BY-38 01/14/20 - 01/14/20 < 190 < 188 < 189 < 190 < 190 < 192 04/14/20 - 04/14/20 < 185 < 181 < 185 < 176 < 175 < 179 07/14/20 - 07/14/20 < 181 < 179 < 177 < 176 < 178 < 179 10/13/20 - 10/13/20 < 186 < 184 < 184 < 181 < 181 < 182 MEAN - - - - - -

C-3

Table C-II.2 CONCENTRATIONS OF GAMMA EMITTERS IN GROUND WATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 BY-14-1 01/14/20 - 01/14/20 < 7 < 8 < 15 < 9 < 14 < 10 < 13 < 10 <8 < 8 < 31 < 11 04/14/20 - 04/14/20 < 7 < 6 < 16 < 9 < 17 < 9 < 12 < 9 <8 < 9 < 32 < 9 07/14/20 - 07/14/20 < 5 < 6 < 13 < 7 < 15 < 8 < 12 < 11 <8 < 6 < 26 < 9 10/13/20 - 10/13/20 < 3 < 3 < 7 < 4 < 7 < 4 < 6 < 4 <4 < 4 < 15 < 5 MEAN - - - - - - - - - - - -

BY-18-1 01/14/20 - 01/14/20 < 5 < 5 < 11 < 7 < 12 < 7 < 12 < 9 <5 < 5 < 29 < 11 04/14/20 - 04/14/20 < 6 < 5 < 14 < 7 < 16 < 9 < 12 < 8 <7 < 7 < 29 < 9 07/14/20 - 07/14/20 < 9 < 8 < 18 < 6 < 11 < 7 < 11 < 11 <9 < 8 < 38 < 5 10/13/20 - 10/13/20 < 4 < 4 < 6 < 4 < 7 < 4 < 6 < 5 <4 < 4 < 16 < 5 MEAN - - - - - - - - - - - -

BY-32 01/14/20 - 01/14/20 < 6 < 5 < 10 < 6 < 13 < 7 < 9 < 5 <6 < 6 < 26 < 5 04/14/20 - 04/14/20 < 7 < 8 < 17 < 7 < 17 < 8 < 11 < 9 < 10 < 11 < 33 < 10 07/14/20 - 07/14/20 < 6 < 6 < 9 < 6 < 13 < 7 < 11 < 9 <6 < 7 < 29 < 9 C-4 10/13/20 - 10/13/20 < 3 < 4 < 7 < 4 < 7 < 4 < 6 < 4 <4 < 4 < 13 < 5 MEAN - - - - - - - - - - - -

BY-35 01/14/20 - 01/14/20 < 5 < 7 < 13 < 6 < 14 < 5 < 12 < 8 <7 < 6 < 25 < 6 04/14/20 - 04/14/20 < 5 < 4 < 11 < 8 < 12 < 6 < 12 < 8 <8 < 6 < 26 < 5 07/14/20 - 07/14/20 < 7 < 7 < 13 < 8 < 11 < 8 < 12 < 12 <7 < 8 < 33 < 7 10/13/20 - 10/13/20 < 3 < 3 < 6 < 3 < 6 < 3 < 5 < 4 <4 < 3 < 11 < 4 MEAN - - - - - - - - - - - -

BY-37 01/14/20 - 01/14/20 < 7 < 6 < 10 < 6 < 14 < 7 < 11 < 9 <9 < 7 < 27 < 5 04/14/20 - 04/14/20 < 6 < 6 < 14 < 7 < 15 < 8 < 13 < 6 <6 < 8 < 28 < 11 07/14/20 - 07/14/20 < 7 < 6 < 13 < 9 < 14 < 7 < 10 < 11 <8 < 6 < 32 < 10 10/13/20 - 10/13/20 < 3 < 3 < 6 < 3 < 6 < 3 < 6 < 4 <3 < 4 < 12 < 4 MEAN - - - - - - - - - - - -

BY-38 01/14/20 - 01/14/20 < 7 < 6 < 15 < 7 < 15 < 8 < 12 < 8 <7 < 5 < 28 < 9 04/14/20 - 04/14/20 < 5 < 6 < 13 < 6 < 13 < 7 < 14 < 7 <6 < 8 < 23 < 8 07/14/20 - 07/14/20 < 7 < 7 < 13 < 5 < 17 < 8 < 13 < 10 <8 < 7 < 29 < 9 10/13/20 - 10/13/20 < 3 < 3 < 6 < 3 < 7 < 3 < 6 < 4 <4 < 4 < 13 < 5 MEAN - - - - - - - - - - - -

Table C-III.1 CONCENTRATIONS OF NICKEL-63 AND GAMMA EMITTERS IN FISH SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION SITE PERIOD Ni-63 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 BY-29 Quillback 05/21/20 - 05/21/20 < 88 < 62 < 53 < 40 < 39 < 118 < 58 < 96 < 57 < 54 < 287 < 117 Shorthead Redhorse 05/21/20 - 05/21/20 < 82 < 66 < 61 < 153 < 70 < 131 < 74 < 109 < 56 < 67 < 368 < 144 Smallmouth Bass 10/21/20 - 10/21/20 < 158 < 45 < 47 < 94 < 46 < 97 < 51 < 79 < 48 < 46 < 211 < 88 Golden Redhorse 10/21/20 - 10/21/20 < 179 < 31 < 36 < 65 < 34 < 66 < 34 < 55 < 39 < 33 < 156 < 62 MEAN - - - - - - - - - - - -

BY-31 Quillback 05/21/20 - 05/21/20 < 118 < 69 < 58 < 108 < 54 < 108 < 54 < 99 < 68 < 48 < 408 < 109 Silver Redhorse 05/21/20 - 05/21/20 < 108 < 47 < 49 < 108 < 35 < 100 < 62 < 97 < 53 < 48 < 279 < 102 C-5 Common Carp 10/21/20 - 10/21/20 < 173 < 31 < 32 < 67 < 38 < 69 < 34 < 58 < 40 < 33 < 128 < 47 Smallmouth Bass 10/21/20 - 10/21/20 < 120 < 33 < 30 < 63 < 37 < 89 < 32 < 68 < 35 < 31 < 155 < 43 MEAN - - - - - - - - - - - -

Table C-IV.1 CONCENTRATIONS OF NICKEL-63 AND GAMMA EMITTERS IN SEDIMENT SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/KG DRY +/- 2 SIGMA COLLECTION SITE PERIOD Ni-63 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 BY-12 05/12/20 - 05/12/20 < 154 < 88 < 51 < 213 < 55 < 212 < 91 < 152 < 96 < 140 < 390 < 68 10/06/20 - 10/06/20 < 209 < 60 < 67 < 133 < 64 < 128 < 64 < 90 < 93 < 87 < 223 < 48 MEAN - - - - - - - - - - - -

BY-34 05/12/20 - 05/12/20 < 153 < 68 < 57 < 132 < 47 < 154 < 73 < 98 < 73 < 69 < 244 < 80 10/06/20 - 10/06/20 < 254 < 45 < 46 < 67 < 54 < 106 < 54 < 80 < 54 < 42 < 164 < 50 MEAN - - - - - - - - - - - -

C-6

Table C-V.1 CONCENTRATIONS OF GROSS BETA IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III PERIOD BY-21 BY-22 BY-23 BY-24 BY-01 BY-04 BY-06 BY-08 12/30/19 - 01/07/20 16 +/- 4 15 +/- 4 13 +/- 4 15 +/- 4 11 +/- 3 9 +/- 3 14 +/- 4 16 +/- 4 01/07/20 - 01/14/20 18 +/- 4 12 +/- 4 17 +/- 4 17 +/- 4 17 +/- 4 12 +/- 4 17 +/- 4 12 +/- 4 01/14/20 - 01/21/20 22 +/- 4 24 +/- 4 21 +/- 4 20 +/- 4 18 +/- 4 23 +/- 4 23 +/- 4 17 +/- 4 01/21/20 - 01/28/20 18 +/- 4 21 +/- 4 16 +/- 4 18 +/- 4 19 +/- 4 18 +/- 4 17 +/- 4 14 +/- 4 01/28/20 - 02/04/20 8 +/- 4 11 +/- 4 8 +/- 4 11 +/- 4 11 +/- 4 9 +/- 4 11 +/- 4 9 +/- 4 02/04/20 - 02/11/20 17 +/- 4 12 +/- 4 10 +/- 4 14 +/- 4 13 +/- 4 13 +/- 4 12 +/- 4 8 +/- 3 02/11/20 - 02/18/20 13 +/- 4 15 +/- 4 12 +/- 4 12 +/- 4 15 +/- 4 15 +/- 4 15 +/- 4 16 +/- 4 02/18/20 - 02/25/20 20 +/- 5 17 +/- 4 19 +/- 5 19 +/- 5 17 +/- 4 20 +/- 5 22 +/- 5 20 +/- 5 02/25/20 - 03/03/20 14 +/- 4 16 +/- 4 16 +/- 4 16 +/- 4 13 +/- 4 14 +/- 4 16 +/- 4 19 +/- 4 03/03/20 - 03/10/20 7 +/- 4 9 +/- 4 8 +/- 4 11 +/- 4 9 +/- 4 6 +/- 3 12 +/- 4 6 +/- 3 03/10/20 - 03/17/20 12 +/- 4 16 +/- 4 18 +/- 4 15 +/- 4 15 +/- 4 17 +/- 4 18 +/- 4 11 +/- 4 03/17/20 - 03/24/20 9 +/- 4 14 +/- 4 12 +/- 4 15 +/- 4 13 +/- 4 17 +/- 4 11 +/- 4 14 +/- 4 03/24/20 - 03/31/20 13 +/- 4 15 +/- 5 11 +/- 4 13 +/- 5 9 +/- 4 13 +/- 4 12 +/- 4 13 +/- 4 03/31/20 - 04/07/20 13 +/- 4 12 +/- 4 11 +/- 4 12 +/- 4 13 +/- 4 13 +/- 4 14 +/- 4 11 +/- 4 04/07/20 - 04/14/20 15 +/- 4 16 +/- 4 16 +/- 4 14 +/- 4 12 +/- 4 16 +/- 4 13 +/- 4 11 +/- 4 04/14/20 - 04/21/20 14 +/- 4 18 +/- 4 16 +/- 4 18 +/- 4 15 +/- 4 15 +/- 4 15 +/- 4 13 +/- 4 04/21/20 - 04/28/20 15 +/- 4 14 +/- 4 16 +/- 4 20 +/- 4 11 +/- 3 15 +/- 4 17 +/- 4 10 +/- 3 04/28/20 - 05/05/20 10 +/- 4 15 +/- 4 11 +/- 4 12 +/- 4 8 +/- 4 8 +/- 4 13 +/- 4 9 +/- 4 05/05/20 - 05/12/20 7 +/- 3 9 +/- 4 8 +/- 3 10 +/- 4 9 +/- 4 9 +/- 4 9 +/- 4 8 +/- 3 05/12/20 - 05/19/20 15 +/- 4 10 +/- 3 11 +/- 3 11 +/- 3 12 +/- 4 14 +/- 4 14 +/- 4 12 +/- 4 05/19/20 - 05/26/20 6 +/- 4 7 +/- 4 < 5 5 +/- 4 6 +/- 4 6 +/- 4 10 +/- 4 8 +/- 4 05/26/20 - 06/02/20 7 +/- 4 9 +/- 4 11 +/- 4 7 +/- 4 8 +/- 4 9 +/- 4 10 +/- 4 12 +/- 4 06/02/20 - 06/09/20 14 +/- 4 11 +/- 4 17 +/- 4 18 +/- 4 13 +/- 4 14 +/- 4 16 +/- 4 14 +/- 4 06/09/20 - 06/16/20 9 +/- 4 8 +/- 3 11 +/- 4 9 +/- 4 7 +/- 3 10 +/- 4 9 +/- 4 12 +/- 4 06/16/20 - 06/23/20 16 +/- 4 17 +/- 4 17 +/- 4 22 +/- 4 20 +/- 4 13 +/- 4 18 +/- 4 20 +/- 4 06/23/20 - 06/30/20 14 +/- 4 13 +/- 4 9 +/- 4 18 +/- 4 12 +/- 4 12 +/- 4 18 +/- 4 13 +/- 4 06/30/20 - 07/07/20 20 +/- 4 25 +/- 4 23 +/- 4 21 +/- 4 21 +/- 4 22 +/- 4 22 +/- 4 25 +/- 4 07/07/20 - 07/14/20 14 +/- 4 15 +/- 4 14 +/- 4 19 +/- 4 16 +/- 4 17 +/- 4 15 +/- 4 11 +/- 4 07/14/20 - 07/21/20 13 +/- 4 15 +/- 4 17 +/- 4 13 +/- 4 12 +/- 4 15 +/- 4 14 +/- 4 15 +/- 4 07/21/20 - 07/28/20 16 +/- 4 13 +/- 4 11 +/- 4 13 +/- 4 14 +/- 4 14 +/- 4 15 +/- 4 14 +/- 4 07/28/20 - 08/04/20 13 +/- 4 12 +/- 4 11 +/- 3 9 +/- 3 11 +/- 3 13 +/- 4 11 +/- 3 11 +/- 3 08/04/20 - 08/11/20 20 +/- 5 20 +/- 4 18 +/- 4 20 +/- 5 18 +/- 5 20 +/- 4 22 +/- 5 20 +/- 4 08/11/20 - 08/18/20 12 +/- 4 19 +/- 5 11 +/- 4 13 +/- 5 13 +/- 4 16 +/- 4 16 +/- 4 18 +/- 4 08/18/20 - 08/25/20 20 +/- 4 23 +/- 4 21 +/- 4 21 +/- 4 21 +/- 4 22 +/- 4 26 +/- 5 24 +/- 4 08/25/20 - 09/01/20 24 +/- 4 18 +/- 4 17 +/- 4 19 +/- 4 23 +/- 4 21 +/- 4 24 +/- 4 19 +/- 4 09/01/20 - 09/08/20 15 +/- 4 20 +/- 4 17 +/- 4 18 +/- 4 16 +/- 4 22 +/- 4 20 +/- 4 17 +/- 4 09/08/20 - 09/15/20 8 +/- 3 10 +/- 3 8 +/- 3 11 +/- 3 10 +/- 3 9 +/- 3 12 +/- 3 7 +/- 3 09/15/20 - 09/22/20 26 +/- 5 27 +/- 5 26 +/- 5 27 +/- 5 25 +/- 5 24 +/- 5 27 +/- 5 23 +/- 4 09/22/20 - 09/29/20 33 +/- 6 29 +/- 5 25 +/- 5 28 +/- 5 26 +/- 5 25 +/- 5 32 +/- 5 27 +/- 5 09/29/20 - 10/06/20 14 +/- 4 7 +/- 4 11 +/- 4 12 +/- 4 10 +/- 4 6 +/- 4 10 +/- 4 10 +/- 4 10/06/20 - 10/13/20 19 +/- 4 18 +/- 4 21 +/- 4 20 +/- 4 18 +/- 4 16 +/- 4 19 +/- 4 18 +/- 4 10/13/20 - 10/20/20 13 +/- 4 15 +/- 5 12 +/- 4 14 +/- 4 15 +/- 5 7 +/- 4 15 +/- 5 13 +/- 4 10/20/20 - 10/27/20 16 +/- 4 13 +/- 4 14 +/- 4 14 +/- 4 15 +/- 4 11 +/- 4 14 +/- 4 14 +/- 4 10/27/20 - 11/03/20 23 +/- 5 22 +/- 5 23 +/- 5 23 +/- 5 18 +/- 4 21 +/- 5 25 +/- 5 23 +/- 5 11/03/20 - 11/10/20 17 +/- 4 20 +/- 4 20 +/- 4 19 +/- 4 20 +/- 4 19 +/- 4 19 +/- 4 19 +/- 4 11/10/20 - 11/17/20 25 +/- 5 22 +/- 5 20 +/- 5 23 +/- 5 23 +/- 5 20 +/- 5 19 +/- 5 23 +/- 5 11/17/20 - 11/24/20 22 +/- 5 21 +/- 5 22 +/- 5 24 +/- 5 25 +/- 5 19 +/- 5 23 +/- 5 21 +/- 5 11/24/20 - 12/01/20 21 +/- 4 18 +/- 4 16 +/- 4 16 +/- 4 18 +/- 4 19 +/- 4 15 +/- 4 17 +/- 4 12/01/20 - 12/08/20 29 +/- 7 21 +/- 5 23 +/- 5 19 +/- 4 21 +/- 5 17 +/- 4 25 +/- 5 17 +/- 4 12/08/20 - 12/15/20 28 +/- 5 27 +/- 5 22 +/- 5 28 +/- 5 31 +/- 5 26 +/- 5 29 +/- 5 34 +/- 6 12/15/20 - 12/22/20 27 +/- 4 25 +/- 4 24 +/- 4 30 +/- 5 23 +/- 4 27 +/- 5 28 +/- 5 19 +/- 4 12/22/20 - 12/29/20 18 +/- 4 17 +/- 4 21 +/- 4 21 +/- 4 16 +/- 4 15 +/- 4 21 +/- 4 19 +/- 4 MEAN +/- 2 STD DEV 16 +/- 12 16 +/- 11 16 +/- 10 17 +/- 11 15 +/- 11 15 +/- 11 17 +/- 11 15 +/- 11 THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES C-7

Table C-V.2 MONTHLY AND YEARLY MEAN VALUES OF GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA GROUP I - NEARSITE LOCATIONS GROUP II - FAR FIELD LOCATIONS GROUP III - CONTROL LOCATIONS COLLECTION MIN MAX MEAN COLLECTION MIN MAX MEAN COLLECTION MIN MAX MEAN PERIOD +/- 2SD PERIOD +/- 2SD PERIOD +/- 2SD 12/30/19 - 02/04/20 8 24 16 +/- 9 12/30/19 - 02/04/20 9 23 15 +/- 9 12/30/19 - 02/04/20 9 17 14 +/- 6 02/04/20 - 03/03/20 10 20 15 +/- 6 02/04/20 - 03/03/20 12 22 15 +/- 6 02/04/20 - 03/03/20 8 20 16 +/- 11 03/03/20 - 03/31/20 7 18 12 +/- 6 03/03/20 - 03/31/20 6 18 13 +/- 7 03/03/20 - 03/31/20 6 14 11 +/- 7 03/31/20 - 04/28/20 11 20 15 +/- 4 03/31/20 - 04/28/20 11 17 14 +/- 3 03/31/20 - 04/28/20 10 13 11 +/- 2 04/28/20 - 06/02/20 5 15 10 +/- 5 04/28/20 - 06/02/20 6 14 10 +/- 5 04/28/20 - 06/02/20 8 12 10 +/- 4 06/02/20 - 06/30/20 8 22 14 +/- 8 06/02/20 - 06/30/20 7 20 13 +/- 8 06/02/20 - 06/30/20 12 20 15 +/- 7 06/30/20 - 08/04/20 9 25 15 +/- 8 06/30/20 - 08/04/20 11 22 15 +/- 7 06/30/20 - 08/04/20 11 25 15 +/- 11 08/04/20 - 09/01/20 11 24 18 +/- 7 08/04/20 - 09/01/20 13 26 20 +/- 8 08/04/20 - 09/01/20 18 24 20 +/- 5 09/01/20 - 09/29/20 8 33 20 +/- 16 09/01/20 - 09/29/20 9 32 21 +/- 15 09/01/20 - 09/29/20 7 27 19 +/- 17 09/29/20 - 11/03/20 7 23 16 +/- 9 09/29/20 - 11/03/20 6 25 15 +/- 11 09/29/20 - 11/03/20 10 23 15 +/- 10 11/03/20 - 12/01/20 16 25 20 +/- 5 11/03/20 - 12/01/20 15 25 20 +/- 5 11/03/20 - 12/01/20 17 23 20 +/- 4 C-8 12/01/20 - 12/29/20 17 30 24 +/- 8 12/01/20 - 12/29/20 15 31 23 +/- 11 12/01/20 - 12/29/20 17 34 22 +/- 16 12/30/19 - 12/29/20 5 33 16 +/- 11 12/30/19 - 12/29/20 6 32 16 +/- 11 12/30/19 - 12/29/20 6 34 15 +/- 11

Table C-V.3 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 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 BY-01 12/30/19 - 03/31/20 < 3 < 4 < 7 < 3 < 7 < 4 < 7 < 2 < 2 < 168 < 76 03/31/20 - 06/30/20 < 3 < 4 < 12 < 3 < 5 < 3 < 9 < 2 < 2 < 194 < 69 06/30/20 - 09/29/20 < 2 < 4 < 10 < 3 < 8 < 5 < 10 < 3 < 3 < 186 < 33 09/29/20 - 12/29/20 < 2 < 4 < 10 < 3 < 7 < 4 < 5 < 3 < 2 < 153 < 54 MEAN - - - - - - - - - - -

BY-04 12/30/19 - 03/31/20 < 2 < 3 < 10 < 2 < 5 < 4 < 6 < 2 < 2 < 170 < 50 03/31/20 - 06/30/20 < 2 < 4 < 6 < 2 < 7 < 4 < 6 < 2 < 2 < 129 < 57 06/30/20 - 09/29/20 < 2 < 3 < 11 < 3 < 6 < 4 < 5 < 2 < 2 < 165 < 74 09/29/20 - 12/29/20 < 2 < 3 < 6 < 2 < 3 < 3 < 5 < 2 < 2 < 101 < 57 MEAN - - - - - - - - - - -

C-9 BY-06 12/30/19 - 03/31/20 < 3 < 4 < 8 < 3 < 6 < 5 < 7 < 2 < 2 < 188 < 82 03/31/20 - 06/30/20 < 3 < 4 < 14 < 3 < 6 < 5 < 7 < 3 < 2 < 250 < 72 06/30/20 - 09/29/20 < 3 < 3 < 11 < 3 < 6 < 4 < 7 < 2 < 2 < 153 < 94 09/29/20 - 12/29/20 < 2 < 3 < 3 < 3 < 6 < 3 < 7 < 2 < 2 < 108 < 50 MEAN - - - - - - - - - - -

BY-08 12/30/19 - 03/31/20 < 2 < 2 < 6 < 2 < 5 < 3 < 5 < 2 < 2 < 159 < 57 03/31/20 - 06/30/20 < 2 < 3 < 11 < 2 < 5 < 4 < 5 < 2 < 1 < 130 < 49 06/30/20 - 09/29/20 < 2 < 3 < 7 < 2 < 5 < 3 < 5 < 2 < 2 < 133 < 31 09/29/20 - 12/29/20 < 2 < 3 < 10 < 2 < 8 < 3 < 5 < 3 < 2 < 94 < 57 MEAN - - - - - - - - - - -

Table C-V.3 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 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 BY-21 12/30/19 - 03/31/20 < 2 < 3 < 10 < 3 < 7 < 4 < 5 < 2 < 2 < 125 < 55 03/31/20 - 06/30/20 < 3 < 4 < 10 < 2 < 6 < 5 < 7 < 2 < 2 < 195 < 64 06/30/20 - 09/29/20 < 3 < 3 < 9 < 3 < 8 < 5 < 7 < 2 < 3 < 243 < 65 09/29/20 - 12/29/20 < 2 < 3 < 7 < 1 < 4 < 3 < 6 < 2 < 2 < 117 < 61 MEAN - - - - - - - - - - -

BY-22 12/30/19 - 03/31/20 < 3 < 3 < 9 < 2 < 5 < 4 < 5 < 2 < 2 < 145 < 50 03/31/20 - 06/30/20 < 4 < 6 < 17 < 5 < 9 < 7 < 12 < 4 < 3 < 278 < 138 06/30/20 - 09/29/20 < 2 < 4 < 11 < 3 < 5 < 3 < 6 < 2 < 2 < 164 < 65 09/29/20 - 12/29/20 < 3 < 4 < 11 < 2 < 8 < 4 < 7 < 3 < 3 < 124 < 49 MEAN - - - - - - - - - - -

C-10 BY-23 12/30/19 - 03/31/20 < 2 < 3 < 7 < 2 < 4 < 3 < 5 < 2 < 2 < 142 < 43 03/31/20 - 06/30/20 < 2 < 2 < 8 < 2 < 5 < 4 < 6 < 1 < 2 < 162 < 26 06/30/20 - 09/29/20 < 2 < 4 < 11 < 3 < 8 < 5 < 8 < 3 < 3 < 203 < 72 09/29/20 - 12/29/20 < 3 < 5 < 17 < 4 < 11 < 6 < 9 < 4 < 4 < 187 < 69 MEAN - - - - - - - - - - -

BY-24 12/30/19 - 03/31/20 < 3 < 3 < 13 < 4 < 7 < 4 < 9 < 3 < 2 < 194 < 63 03/31/20 - 06/30/20 < 3 < 4 < 12 < 3 < 6 < 4 < 8 < 2 < 3 < 197 < 108 06/30/20 - 09/29/20 < 3 < 5 < 14 < 4 < 10 < 6 < 11 < 5 < 3 < 288 < 115 09/29/20 - 12/29/20 < 3 < 4 < 10 < 3 < 6 < 3 < 6 < 2 < 2 < 146 < 50 MEAN - - - - - - - - - - -

Table C-VI.1 CONCENTRATIONS OF I-131 IN AIR IODINE SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III PERIOD BY-21 BY-22 BY-23 BY-24 BY-01 BY-04 BY-06 BY-08 12/30/19 - 01/07/20 < 23 < 38 < 38 < 16 < 19 < 23 < 23 < 23 01/07/20 - 01/14/20 < 31 < 31 < 31 < 31 < 28 < 28 < 28 < 28 01/14/20 - 01/21/20 < 33 < 33 < 33 < 33 < 37 < 37 < 19 < 38 01/21/20 - 01/28/20 < 38 < 38 < 38 < 38 < 27 < 27 < 27 < 27 01/28/20 - 02/04/20 < 28 < 28 < 28 < 28 < 29 < 29 < 29 < 29 02/04/20 - 02/11/20 < 45 < 45 < 46 < 46 < 25 < 25 < 25 < 25 02/11/20 - 02/18/20 < 50 < 50 < 50 < 50 < 23 < 23 < 19 < 23 02/18/20 - 02/25/20 < 27 < 26 < 26 < 26 < 20 < 48 < 48 < 48 02/25/20 - 03/03/20 < 52 < 49 < 49 < 49 < 31 < 31 < 31 < 31 03/03/20 - 03/10/20 < 26 < 20 < 22 < 20 < 39 < 39 < 39 < 39 03/10/20 - 03/17/20 < 56 < 56 < 56 < 56 < 41 < 41 < 41 < 41 03/17/20 - 03/24/20 < 36 < 36 < 36 < 36 < 31 < 31 < 31 < 32 03/24/20 - 03/31/20 < 54 < 54 < 54 < 54 < 34 < 40 < 34 < 34 03/31/20 - 04/07/20 < 37 < 31 < 37 < 37 < 52 < 53 < 53 < 53 04/07/20 - 04/14/20 < 44 < 44 < 44 < 44 < 24 < 29 < 29 < 29 04/14/20 - 04/21/20 < 46 < 46 < 19 < 46 < 37 < 37 < 38 < 38 04/21/20 - 04/28/20 < 33 < 33 < 33 < 33 < 45 < 45 < 45 < 45 04/28/20 - 05/05/20 < 41 < 40 < 40 < 40 < 63 < 63 < 63 < 63 05/05/20 - 05/12/20 < 26 < 26 < 26 < 15 < 43 < 43 < 43 < 43 05/12/20 - 05/19/20 < 34 < 34 < 34 < 34 < 42 < 42 < 42 < 43 05/19/20 - 05/26/20 < 31 < 31 < 31 < 31 < 45 < 45 < 45 < 45 05/26/20 - 06/02/20 < 69 < 69 < 69 < 69 < 68 < 69 < 69 < 69 06/02/20 - 06/09/20 < 26 < 26 < 26 < 26 < 34 < 34 < 35 < 35 06/09/20 - 06/16/20 < 24 < 24 < 24 < 24 < 34 < 34 < 34 < 34 06/16/20 - 06/23/20 < 30 < 30 < 30 < 30 < 36 < 36 < 36 < 36 06/23/20 - 06/30/20 < 64 < 64 < 64 < 64 < 49 < 49 < 49 < 50 06/30/20 - 07/07/20 < 28 < 28 < 28 < 29 < 48 < 48 < 48 < 48 07/07/20 - 07/14/20 < 63 < 63 < 64 < 63 < 64 < 64 < 64 < 64 07/14/20 - 07/21/20 < 64 < 64 < 64 < 64 < 62 < 62 < 62 < 26 07/21/20 - 07/28/20 < 40 < 40 < 19 < 40 < 42 < 42 < 42 < 42 07/28/20 - 08/04/20 < 53 < 53 < 53 < 53 < 54 < 54 < 54 < 23 08/04/20 - 08/11/20 < 29 < 29 < 29 < 32 < 54 < 48 < 49 < 48 08/11/20 - 08/18/20 < 48 < 48 < 48 < 66 < 65 < 65 < 65 < 65 08/18/20 - 08/25/20 < 48 < 48 < 49 < 48 < 54 < 55 < 55 < 55 08/25/20 - 09/01/20 < 61 < 61 < 61 < 61 < 63 < 63 < 63 < 63 09/01/20 - 09/08/20 < 60 < 60 < 60 < 60 < 45 < 46 < 46 < 46 09/08/20 - 09/15/20 < 33 < 33 < 33 < 33 < 63 < 63 < 63 < 63 09/15/20 - 09/22/20 < 66 < 66 < 66 < 66 < 66 < 66 < 67 < 67 09/22/20 - 09/29/20 < 57 < 52 < 52 < 52 < 35 < 35 < 35 < 35 09/29/20 - 10/06/20 < 42 < 39 < 39 < 39 < 38 < 38 < 39 < 39 10/06/20 - 10/13/20 < 25 < 56 < 56 < 56 < 25 < 25 < 26 < 11 10/13/20 - 10/20/20 < 49 < 49 < 25 < 49 < 39 < 39 < 39 < 39 10/20/20 - 10/27/20 < 68 < 68 < 68 < 68 < 69 < 69 < 69 < 69 10/27/20 - 11/03/20 < 35 < 35 < 27 < 35 < 46 < 46 < 46 < 47 11/03/20 - 11/10/20 < 38 < 39 < 39 < 38 < 33 < 33 < 33 < 33 11/10/20 - 11/17/20 < 26 < 55 < 55 < 55 < 63 < 62 < 64 < 65 11/17/20 - 11/24/20 < 60 < 60 < 60 < 25 < 57 < 57 < 57 < 58 11/24/20 - 12/01/20 < 44 < 44 < 23 < 44 < 47 < 47 < 47 < 47 12/01/20 - 12/08/20 < 38 < 37 < 37 < 37 < 34 < 34 < 34 < 34 12/08/20 - 12/15/20 < 38 < 38 < 38 < 38 < 25 < 25 < 25 < 25 12/15/20 - 12/22/20 < 34 < 51 < 51 < 51 < 44 < 44 < 45 < 45 12/22/20 - 12/29/20 < 52 < 52 < 52 < 52 < 65 < 65 < 65 < 65 MEAN - - - - - - - -

C-11

Table C-VII.1 CONCENTRATIONS OF I-131 IN MILK SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION CONTROL FARM INDICATOR FARM PERIOD BY-26-2 BY-20-1 01/07/20 < 0.6 < 0.7 02/04/20 < 0.6 < 0.6 03/03/20 < 0.6 < 0.5 04/07/20 < 0.6 < 0.7 05/05/20 < 0.6 < 0.7 05/19/20 < 0.7 < 0.7 06/02/20 < 0.6 < 0.7 06/16/20 < 0.5 < 0.8 06/30/20 < 0.8 < 0.8 07/14/20 < 0.9 < 0.8 07/28/20 < 0.9 < 0.9 08/11/20 < 0.8 < 0.9 08/25/20 < 0.8 < 0.7 09/08/20 < 0.8 < 0.8 09/22/20 < 0.5 < 0.6 10/06/20 < 0.7 < 0.6 10/20/20 < 0.7 < 0.9 11/03/20 < 0.8 < 0.9 12/01/20 < 0.8 < 0.9 MEAN - -

C-12

Table C-VII.2 CONCENTRATIONS OF GAMMA EMMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 BY-20-1 01/07/20 < 7 < 6 < 17 < 10 < 20 < 8 < 17 < 10 < 9 < 31 < 9 02/04/20 < 7 < 8 < 17 < 8 < 18 < 9 < 12 < 10 < 8 < 31 < 10 03/03/20 < 8 < 8 < 18 < 7 < 19 < 9 < 16 < 10 < 7 < 27 < 9 04/07/20 < 8 < 7 < 19 < 8 < 17 < 8 < 14 < 9 < 9 < 35 < 13 05/05/20 < 9 < 9 < 17 < 8 < 22 < 8 < 14 < 11 < 10 < 37 < 12 05/19/20 < 8 < 6 < 18 < 7 < 21 < 9 < 16 < 9 < 10 < 34 < 12 06/02/20 < 7 < 7 < 15 < 9 < 15 < 7 < 13 < 8 < 7 < 33 < 8 06/16/20 < 7 < 7 < 14 < 8 < 14 < 7 < 12 < 8 < 7 < 23 < 7 06/30/20 < 8 < 9 < 19 < 9 < 19 < 11 < 16 < 10 < 9 < 47 < 11 07/14/20 < 8 < 9 < 14 < 8 < 20 < 9 < 14 < 9 < 6 < 36 < 6 07/28/20 < 8 < 7 < 18 < 10 < 23 < 9 < 12 < 9 < 9 < 33 < 7 08/11/20 < 8 < 8 < 20 < 10 < 14 < 8 < 14 < 9 < 8 < 37 < 10 08/25/20 < 8 < 8 < 18 < 7 < 20 < 9 < 16 < 6 < 8 < 24 < 8 09/08/20 < 9 < 9 < 12 < 8 < 14 < 8 < 15 < 8 < 10 < 37 < 11 09/22/20 < 7 < 7 < 19 < 8 < 20 < 9 < 13 < 9 < 8 < 32 < 9 10/06/20 < 7 < 6 < 13 < 7 < 20 < 7 < 11 < 9 < 8 < 27 < 10 10/20/20 < 6 < 5 < 15 < 6 < 15 < 6 < 10 < 6 < 6 < 21 < 7 C-13 11/03/20 < 8 < 7 < 13 < 8 < 14 < 9 < 12 < 9 < 8 < 25 < 6 12/01/20 < 8 < 7 < 19 < 9 < 17 < 8 < 13 < 9 < 8 < 31 < 10 MEAN - - - - - - - - - - -

BY-26-2 01/07/20 < 9 < 9 < 19 < 11 < 20 < 9 < 14 < 11 < 9 < 38 < 10 02/04/20 < 7 < 8 < 16 < 8 < 18 < 9 < 15 < 10 < 8 < 28 < 8 03/03/20 < 7 < 7 < 18 < 14 < 28 < 10 < 14 < 7 < 11 < 35 < 12 04/07/20 < 6 < 6 < 15 < 5 < 16 < 6 < 13 < 6 < 7 < 28 < 10 05/05/20 < 11 < 8 < 24 < 12 < 18 < 10 < 16 < 11 < 9 < 32 < 10 05/19/20 < 7 < 9 < 18 < 10 < 20 < 9 < 16 < 10 < 8 < 29 < 9 06/02/20 < 7 < 7 < 16 < 8 < 13 < 7 < 14 < 8 < 8 < 32 < 7 06/16/20 < 7 < 7 < 17 < 5 < 20 < 7 < 12 < 8 < 8 < 31 < 6 06/30/20 < 6 < 8 < 13 < 6 < 16 < 5 < 10 < 6 < 5 < 28 < 10 07/14/20 < 9 < 9 < 17 < 8 < 20 < 8 < 13 < 8 < 8 < 33 < 9 07/28/20 < 8 < 8 < 18 < 10 < 16 < 7 < 14 < 7 < 9 < 29 < 8 08/11/20 < 9 < 7 < 18 < 10 < 20 < 8 < 14 < 8 < 8 < 30 < 10 08/25/20 < 6 < 7 < 14 < 7 < 15 < 7 < 12 < 7 < 7 < 29 < 8 09/08/20 < 8 < 8 < 20 < 9 < 17 < 8 < 14 < 9 < 9 < 37 < 11 09/22/20 < 7 < 9 < 17 < 9 < 19 < 8 < 17 < 8 < 8 < 34 < 7 10/06/20 < 6 < 6 < 13 < 8 < 16 < 6 < 11 < 7 < 7 < 23 < 9 10/20/20 < 7 < 6 < 20 < 10 < 19 < 9 < 15 < 9 < 10 < 34 < 11 11/03/20 < 8 < 7 < 13 < 7 < 22 < 7 < 12 < 9 < 8 < 33 < 9 12/01/20 < 9 < 7 < 13 < 8 < 21 < 10 < 14 < 7 < 9 < 31 < 9 MEAN - - - - - - - - - - -

Table C-VIII.1 CONCENTRATIONS OF GAMMA EMITTERS IN VEGETATION SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/KG WET +/- 2 SIGMA COLLECTION SITE PERIOD Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 BY-CONTROL Red Beets 08/05/20 < 28 < 28 < 68 < 30 < 70 < 23 < 50 < 39 < 38 < 32 < 119 < 26 Pepper 09/09/20 < 33 < 34 < 75 < 30 < 76 < 36 < 59 < 51 < 33 < 32 < 151 < 51 MEAN - - - - - - - - - - - -

BY-QUAD 1 Potato/Onion 08/03/20 < 28 < 18 < 44 < 29 < 41 < 27 < 39 < 42 < 25 < 25 < 99 < 22 Soy Beans 09/09/20 < 34 < 36 < 75 < 38 < 74 < 36 < 60 < 58 < 37 < 35 < 179 < 50 MEAN - - - - - - - - - - - -

BY-QUAD 2 Beet Leaves 08/03/20 < 18 < 17 < 37 < 19 < 36 < 18 < 29 < 29 < 19 < 18 < 82 < 26 C-14 Beets 08/03/20 < 33 < 28 < 80 < 30 < 67 < 37 < 58 < 54 < 34 < 32 < 131 < 48 MEAN - - - - - - - - - - - -

BY-QUAD 3 Potatoes 08/03/20 < 28 < 37 < 79 < 40 < 85 < 28 < 59 < 54 < 37 < 32 < 172 < 41 Corn 09/09/20 < 32 < 29 < 64 < 31 < 63 < 34 < 49 < 50 < 34 < 31 < 137 < 42 MEAN - - - - - - - - - - - -

BY-QUAD 4 Potato/Onion 08/03/20 < 24 < 22 < 46 < 21 < 46 < 24 < 40 < 41 < 26 < 25 < 110 < 36 Onion Leaves 08/03/20 < 26 < 32 < 62 < 37 < 64 < 29 < 43 < 51 < 32 < 34 < 149 < 53 MEAN - - - - - - - - - - - -

Table C-IX.1 QUARTERLY OSLD RESULTS FOR BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF MREM/QUARTER +/- 2 STANDARD DEVIATIONS STATION MEAN CODE +/- 2 S.D. JAN - MAR APR - JUN JUL - SEP OCT - DEC BY-01-1 19 +/- 1 18 20 19 18 BY-04-1 22 +/- 3 20 23 23 22 BY-06-1 18 +/- 1 18 18 19 18 BY-08-1 (Ctrl) 18 +/- 2 17 17 18 19 BY-21-1 16 +/- 2 15 17 16 17 BY-22-1 23 +/- 0 23 23 23 23 BY-23-1 22 +/- 3 20 22 23 22 BY-24-2 19 +/- 2 19 19 19 20 BY-101-1 17 +/- 1 17 16 17 17 BY-101-2 17 +/- 3 16 16 17 18 BY-102-1 23 +/- 4 21 24 22 25 BY-102-2 23 +/- 6 19 24 25 24 BY-103-1 21 +/- 3 21 20 21 23 BY-103-2 23 +/- 2 23 23 25 23 BY-103-3 21 +/- 2 20 22 20 22 BY-104-1 23 +/- 3 21 24 22 23 BY-104-2 23 +/- 2 22 22 25 23 BY-104-3 20 +/- 3 20 21 18 21 BY-105-1 23 +/- 2 21 23 24 23 BY-105-2 24 +/- 3 23 25 25 23 BY-106-1 22 +/- 1 22 22 22 22 BY-106-2 22 +/- 3 20 23 21 22 BY-107-1 25 +/- 1 24 24 25 25 BY-107-2 25 +/- 1 24 24 25 25 BY-107-3 21 +/- 1 20 21 21 21 BY-108-1 23 +/- 3 21 25 22 24 BY-108-2 21 +/- 3 20 19 22 22 BY-109-1 21 +/- 4 19 20 23 23 BY-109-2 21 +/- 2 20 21 20 22 BY-110-1 20 +/- 1 20 21 20 21 BY-110-2 21 +/- 2 20 21 20 22 BY-111-3 23 +/- 3 22 25 21 24 BY-111-4 23 +/- 2 21 23 23 23 BY-112-3 22 +/- 1 22 22 23 22 BY-112-4 22 +/- 3 21 22 20 24 BY-113-1 22 +/- 3 20 23 23 24 BY-113-2 19 +/- 1 19 18 19 20 BY-114-1 19 +/- 1 18 19 19 19 BY-114-2 21 +/- 2 21 21 21 23 BY-115-1 22 +/- 3 20 21 23 23 BY-115-2 20 +/- 3 19 21 19 22 BY-116-1 20 +/- 2 19 21 20 21 BY-116-2 19 +/- 2 19 19 21 19 BY-116-3 20 +/- 2 19 21 21 21 BY-201-3 22 +/- 1 22 21 22 22 BY-201-4 23 +/- 4 22 26 22 23 BY-202-1 22 +/- 3 22 24 21 23 BY-202-2 24 +/- 1 25 25 25 24 BY-203-1 19 +/- 3 19 20 17 20 C-15

Table C-IX.1 QUARTERLY OSLD RESULTS FOR BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF MREM/QUARTER +/- 2 STANDARD DEVIATIONS STATION MEAN CODE +/- 2 S.D. JAN - MAR APR - JUN JUL - SEP OCT - DEC BY-203-2 21 +/- 3 20 22 21 23 BY-204-1 20 +/- 2 19 21 19 21 BY-204-2 23 +/- 1 22 23 23 24 BY-205-1 23 +/- 2 23 25 23 23 BY-205-2 21 +/- 3 21 23 19 22 BY-206-1 23 +/- 3 22 25 22 24 BY-206-2 23 +/- 4 21 26 24 23 BY-207-1 24 +/- 3 23 25 24 26 BY-207-2 23 +/- 1 23 24 23 22 BY-208-1 24 +/- 4 23 27 23 25 BY-208-2 23 +/- 4 22 25 21 24 BY-209-1 24 +/- 4 21 24 25 24 BY-209-4 24 +/- 0 24 25 24 25 BY-210-3 22 +/- 4 20 25 22 23 BY-210-4 22 +/- 2 20 23 22 22 BY-211-1 23 +/- 3 21 25 23 23 BY-211-4 23 +/- 3 22 25 23 24 BY-212-1 25 +/- 2 23 25 25 25 BY-212-4 24 +/- 2 24 26 23 25 BY-213-1 23 +/- 3 23 23 22 25 BY-213-4 24 +/- 1 23 24 24 23 BY-214-1 24 +/- 2 22 25 24 24 BY-214-4 23 +/- 1 22 23 23 23 BY-215-1 22 +/- 3 21 24 21 23 BY-215-4 23 +/- 2 23 24 22 23 BY-216-1 25 +/- 3 23 27 25 26 BY-216-2 23 +/- 3 22 24 21 24 BY-301-1 16 +/- 2 15 17 17 17 BY-301-2 20 +/- 3 19 21 18 20 BY-309-1 21 +/- 3 21 23 19 22 BY-309-2 23 +/- 2 21 23 23 23 BY-309-3 21 +/- 2 19 22 22 21 BY-309-4 20 +/- 1 19 20 20 19 BY-314-2 18 +/- 3 17 18 17 20 C-16

TABLE C-IX.2 MEAN QUARTERLY OSLD RESULTS FOR THE INNER RING, OUTER RING, SPECIAL INTEREST, OTHER, AND CONTROL LOCATIONS FOR BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF MILLIREM/STD. QUARTER +/- 2 STANDARD DEVIATION COLLECTION INNER RING OUTER RING SPECIAL INTEREST OTHER CONTROL PERIOD +/- 2 S.D. +/- 2 S.D. +/- 2 S.D. +/- 2 S.D. +/- 2 S.D.

JAN-MAR 20 +/- 4 22 +/- 3 19 +/- 4 19 +/- 5 17 +/- 0 APR-JUN 22 +/- 4 24 +/- 3 21 +/- 5 20 +/- 5 17 +/- 0 JUL-SEP 21 +/- 4 22 +/- 4 20 +/- 5 20 +/- 6 18 +/- 0 OCT-DEC 22 +/- 4 23 +/- 3 20 +/- 4 20 +/- 5 19 +/- 0 TABLE C-IX.3

SUMMARY

OF THE AMBIENT DOSIMETRY PROGRAM FOR BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF MILLIREM/STD. QUARTER +/- 2 STANDARD DEVIATION SAMPLES PERIOD PERIOD PERIOD MEAN LOCATION ANALYZED MINIMUM MAXIMUM +/- 2 S.D.

INNER RING 144 16 25 21 +/- 4 C-17 OUTER RING 128 17 27 23 +/- 4 SPECIAL INTEREST 28 15 23 20 +/- 4 OTHER 28 15 23 20 +/- 5 CONTROL 4 17 19 18 +/- 2 INNER RING STATIONS - BY-101-1, BY-101-2, BY-102-1, BY-102-2, BY-103-1, BY-103-2, BY-103-3, BY-104-1, BY-104-2, BY-104-3, BY-105-1, BY-105-2, BY-106-1, BY-106-2, BY-107-1, BY-107-2, BY-107-3, BY-108-1, BY-108-2, BY-109-1, BY-109-2, BY-110-1, BY-110-2, BY-111-3, BY-111-4, BY-112-3, BY-112-4, BY-113-1, BY-113-2, BY-114-1, BY-114-2, BY-115-1, BY-115-2, BY-116-1, BY-116-2, BY-116-3 OUTER RING STATIONS - BY-201-3, BY-201-4, BY-202-1, BY-202-2, BY-203-1, BY-203-2, BY-204-1, BY-204-2, BY-205-1, BY-205-2, BY-206-1, BY-206-2, BY-207-1, BY-207-2, BY-208-1, BY-208-2, BY-209-1, BY-209-4, BY-210-3, BY-210-4, BY-211-1, BY-211-4, BY-212-1, BY-212-4, BY-213-1, BY-213-4, BY-214-1, BY-214-4, BY-215-1, BY-215-4, BY-216-1, BY-216-2 SPECIAL INTEREST STATIONS - BY-301-1, BY-301-2, BY-309-1*, BY-309-2*, BY-309-3*, BY-309-4*, BY-314-2 OTHER STATIONS - BY-01-1, BY-04-1, BY-06-1, BY-21-1, BY-22-1,BY-23-1, BY-24 CONTROL STATION - BY-08-1

For ISFSI Monitoring

FIGURE C-1 Surface Water - Gross Beta - Stations BY-12 and BY-29 (C)

Collected in the Vicinity of BNGS, 2000 - 2020 BY-12 Oregon Pool of Rock River, Downstream 10.0 8.0 6.0 pCi/L 4.0 2.0 0.0 01-25-00 04-20-05 07-15-10 10-09-15 01-02-21 BY-29 (C) Byron, Rock River Upstream 14.0 12.0 10.0 8.0 pCi/L 6.0 4.0 2.0 0.0 01-25-00 04-20-05 07-15-10 10-09-15 01-02-21 DUE TO VENDOR CHANGE IN 2005, < VALUES ARE LLD VALUES JANUARY THROUGH JUNE 2005 AND MDC VALUES AFTER JUNE 2005 C-18

FIGURE C-2 Surface Water - Tritium - Stations BY-12 and BY-29 (C)

Collected in the Vicinity of BNGS, 2000 - 2020 BY-12 Oregon Pool of Rock River, Downstream 10000 1000 pCi/L 100 10 03-28-00 06-06-05 08-15-10 10-24-15 01-01-21 BY-29 (C) Byron, Rock River Upstream 250 200 150 pCi/L 100 50 0

03-28-00 06-06-05 08-15-10 10-24-15 01-01-21 DUE TO VENDOR CHANGE IN 2005, < VALUES ARE LLD VALUES JANUARY THROUGH JUNE 2005 AND MDC VALUES AFTER JUNE 2005 C-19

FIGURE C-3 Ground Water - Tritium - Station BY-14-1 Collected in the Vicinity of BNGS, 2000 - 2020 BY-14-1 3200 N. German Church Road Well 250 200 150 pCi/L 100 50 0

01-04-00 04-03-05 07-02-10 09-30-15 12-28-20 DUE TO VENDOR CHANGE IN 2005, < VALUES ARE LLD VALUES JANUARY THROUGH JUNE 2005 AND MDC VALUES AFTER JUNE 2005 C-20

FIGURE C-4 Ground Water - Tritium - Station BY-18-1 Collected in the Vicinity of BNGS, 2010 - 2020 BY-18-1 Calhoun Well 250 200 150 pCi/L 100 50 0

07-01-10 02-14-13 10-01-15 05-17-18 12-31-20 C-21

FIGURE C-5 Ground Water - Tritium - Station BY-32 Collected in the Vicinity of BNGS, 2000 - 2020 BY-32 Krueger Well 250 200 150 pCi/L 100 50 0

01-01-00 04-01-05 07-01-10 09-30-15 12-29-20 DUE TO VENDOR CHANGE IN 2005, < VALUES ARE LLD VALUES JANUARY THROUGH JUNE 2005 AND MDC VALUES AFTER JUNE 2005 C-22

FIGURE C-6 Ground Water - Tritium - Station BY-35 Collected in the Vicinity of BNGS, 2006 - 2020 BY-35 Vancko Well 250 200 150 pCi/L 100 50 0

04-01-06 03-01-11 01-29-16 12-28-20 C-23

FIGURE C-7 Ground Water - Tritium - Station BY-37 Collected in the Vicinity of BNGS, 2006 - 2020 BY-37 Cavage Well 250 200 150 pCi/L 100 50 0

04-01-06 03-02-11 01-31-16 12-31-20 Ground Water - Tritium - Station BY-38 Collected in the Vicinity of BNGS, 2006 - 2020 BY-38 Steve Storz Well 250 200 150 pCi/L 100 50 0

07-13-15 08-16-16 09-20-17 10-25-18 11-29-19 01-02-21 C-24

FIGURE C-8 Air Particulate - Gross Beta - Stations BY-08 (C) and BY-21 Collected in the Vicinity of BNGS, 2000 - 2020 BY-08 (C) Leaf River WNW 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-04-00 03-17-04 05-29-08 08-10-12 10-22-16 01-03-21 BY-21 Byron Nearsite N 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-04-00 04-04-05 07-04-10 10-03-15 01-01-21 C-25

FIGURE C-9 Air Particulate - Gross Beta - Stations BY-22 and BY-23 Collected in the Vicinity of BNGS, 2000 - 2020 BY-22 Byron Nearsite SE 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-04-00 04-04-05 07-04-10 10-03-15 01-01-21 BY-23 Byron Nearsite S 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-04-00 04-04-05 07-04-10 10-03-15 01-01-21 C-26

FIGURE C-10 Air Particulate - Gross Beta - Station BY-24 Collected in the Vicinity of BNGS, 2000 - 2020 BY-24 Byron Nearsite SW 70.0 60.0 50.0 10E-03 pCi/m3 40.0 30.0 20.0 10.0 0.0 01-04-00 04-04-05 07-04-10 10-03-15 01-01-21 C-27

FIGURE C-11 Air Particulate - Gross Beta - Stations BY-01 and BY-04 Collected in the Vicinity of BNGS, 2005 - 2020 BY-01 Byron N 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-05-05 08-10-08 09-16-11 10-22-14 11-27-17 01-02-21 BY-04 Paynes Point SE 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-05-05 08-10-08 09-16-11 10-22-14 11-27-17 01-02-21 Regular analysis of far field air particulate & gross beta did not take place prior to 2005 C-28

FIGURE C-12 Air Particulate - Gross Beta - Station BY-06 Collected in the Vicinity of BNGS, 2005 - 2020 BY-06 Oregon SSW 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-05-05 08-10-08 09-16-11 10-22-14 11-27-17 01-02-21 Regular analysis of far field air particulate & gross beta did not take place prior to 2005 C-29

Intentionally left blank APPENDIX D INTER-LABORATORY COMPARISON PROGRAM

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

APPENDIX E EFFLUENT REPORT

Intentionally left blank TABLE OF CONTENTS

SUMMARY

................................................................................................................................. 1 INTRODUCTION ........................................................................................................................ 2 1.0. EFFLUENTS.......................................................................................................... 3 1.1. Gaseous Effluents to the Atmosphere ........................................................ 3 1.2. Liquids Released to Rock River ................................................................... 3 2.0. SOLID RADIOACTIVE WASTE .............................................................................. 3 3.0. DOSE TO MAN ...................................................................................................... 4 3.1. Gaseous Effluent Pathways ........................................................................ 4 3.1.1. Noble Gases ................................................................................ 4 3.1.1.1. Gamma Dose Rates ..................................................... 4 3.1.1.2. Beta Air and Skin Dose Rate......................................... 4 3.1.2. Radioactive Iodine & Particulate ................................................... 4 3.1.3. Gaseous Total Dose ..................................................................... 5 3.2. Liquid Effluent Pathways ............................................................................. 5 3.3. Total Dose.................................................................................................. 6 3.4. Assessment of Dose to Member of Public ................................................... 6 4.0. SOLID RADIOACTIVE WASTE ............................................................................. 6 APPENDIX E-1 DATA TABLES AND FIGURES Station Releases Table 1.1-1 Gaseous Effluents .......................................................................................E-1-1 Table 1.2-1 Liquid Effluents ............................................................................................E-1-3 Table 3.1-1 40CFR190 Maximum Doses Resulting from Liquid Releases ...................... E-1-5 Table 3.2-1 40CFR190 Maximum Doses Resulting from Gaseous Releases ................. E-1-6 Table 3.3-1 40CFR190 Uranium Fuel Cycle Report - Total Dose................................... E-1-8 Table 3.4-1 Maximum Doses Resulting from Airborne Releases Based On Concurrent Meteorological Data .......................................................E-1-10 i

E-1

SUMMARY

Calculations based on gaseous and liquid effluents and meteorological data indicate that public dose due to radioactive material attributable to Byron Station during the period does not exceed regulatory or Offsite Dose Calculation Manual (ODCM) limits.

The Total Effective Dose Equivalent (TEDE) due to licensed activities at Byron Station calculated for the maximum exposed individual for the period is 3.14E-01 mrem. The annual limit on TEDE is 100 mrem.

The assessment of radiation doses to the public is performed in accordance with the ODCM. The results of these analyses confirm that the station is operating in compliance with 10CFR50 Appendix I, 10CFR20 and 40CFR190.

There were no additional operational controls implemented which affected the areas of radiological effluents in 2020.

There were no measurements which exceeded the reporting levels, including any which would not have been attributable to station effluents.

The results of the current radiological environmental monitoring program are approximately the same as those found during the pre-operational studies conducted at Byron Station.

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INTRODUCTION Liquid effluents from Byron Station are released to the Rock River in controlled batches after radioassay of each batch. Gaseous effluents are released to the atmosphere and are calculated on the basis of analyses of weekly grab samples and grab samples of batch releases prior to the release of noble gases as well as continuously collected composite samples of iodine and particulate radioactivity sampled during the course of the year. The results of effluent analyses are summarized on a monthly basis. Airborne concentrations of noble gases, I-131, and particulate radioactivity in offsite areas are calculated using isotopic composition of effluents and meteorological data. C-14 concentration in offsite areas is calculated based on industry-approved methodology for estimation of the amount released and meteorological data.

Environmental monitoring is conducted by sampling at indicator and control (background) locations in the vicinity of Byron Station to measure changes in radiation or radioactivity levels that may be attributable to station operation. If significant changes attributable to Byron Station are measured, these changes are correlated with effluent releases. An environmental monitoring program is conducted which also includes all potential pathways at the site. Gaseous pathways include ground plane (direct), inhalation, vegetation, meat, and milk. Liquid pathways include potable water and freshwater fish. The critical pathway for 2020 gaseous dose was vegetation. The critical pathway for 2020 liquid dose was freshwater fish.

E-3

1.0 RELEASES 1.1 Gaseous Effluents to the Atmosphere Measured concentrations and isotopic composition of noble gases, radioiodine, tritium and particulate radioactivity released to the atmosphere during the year are listed in Table 1.1-1.

A total of 3.86E+00 curies of fission and activation gases were released with a maximum average quarterly release rate of 1.01E+00 µCi/sec.

A total of 1.48E-06 curies of I-131 were released during the year with a maximum average quarterly release rate of 1.88E-07 µCi/sec.

A total of 1.50E-04 curies were released as airborne particulate matter with a maximum average quarterly release rate of 9.93E-06 µCi/sec.

A total of 8.91E+00 curies of other (C-14) radioisotopes were released with a maximum average quarterly release rate of 3.35E-01 µCi/sec.

A total of 4.78E+01 curies of tritium were released with a maximum average quarterly release rate of 1.86E+00 µCi/sec.

Gross alpha-emitting radionuclides were below detectable limits.

1.2 Liquids Released to Rock River A total of 2.84E+10 liters of radioactive liquid wastes containing 1.04E-01 curies of fission and activation products were discharged with a maximum quarterly average concentration of 4.69E-09 µCi/ml.

A total of 2.80E+03 curies of tritium were discharged with a maximum quarterly average concentration of 1.96E-04 µCi/ml.

A total of 9.98E-04 curies of dissolved and entrained gases were discharged with a maximum quarterly average concentration of 8.50E-11 µCi/ml.

Gross alpha-emitting radionuclides were below detectable limits.

Quarterly release totals of principal radionuclides in liquid effluents are given in Table 1.2-1.

2.0 SOLID RADIOACTIVE WASTE Solid radioactive wastes were shipped by truck. For detail, refer to Byron Station 2020 Annual Radiological Effluent Release Report.

E-4

3.0 DOSE TO MAN 3.1 Gaseous Effluent Pathways Table 3.2-1 summarizes the doses resulting from releases of airborne radioactivity via the different exposure pathways.

3.1.1 Noble Gas 3.1.1.1 Gamma Dose Rates Offsite Gamma air and whole body dose rates are shown in Table 3.2-1 and were calculated based on measured release rates, isotopic composition of the noble gases, and average meteorological data for the period. Dose rates based on concurrent meteorological data are shown in Table 3.4-1. Based on measured effluents and average meteorological data, the maximum gamma air dose was 2.84E-04 mrad based on measured effluents and average meteorological data, and 6.25E-05 mrad based on measured effluents and concurrent meteorological data.

(Table 3.4-1).

3.1.1.2 Beta Air and Skin Dose Rates The range of beta particles in air is relatively small (on the order of a few meters or less); consequently, plumes of gaseous effluents may be considered "semi-infinite" for purpose of calculating the dose from beta radiation incident on the skin. However, the actual dose to sensitive skin tissues is difficult to calculate due to the effect of the beta particle energies, thickness of inert skin and clothing covering sensitive tissues. For purposes of this report the skin is taken to have a thickness of 7.0 mg/cm2 and an occupancy factor of 1.0 is used. The skin dose based on measured effluents and average meteorological data was 7.90E-05 mrem, and 8.38E-05 mrem based on measured effluents and concurrent meteorological data.

The maximum offsite beta air dose for the year based on measured effluents and average meteorological data was 6.86E-05 mrad. The beta air dose based on measured effluents and concurrent meteorological data was 5.46E-05 mrad.

3.1.2 Radioactive Iodine & Particulate The human thyroid exhibits a significant capacity to concentrate ingested or inhaled iodine. I-131 released during routine operation of the station may be made available to man resulting in a dose to E-5

the thyroid. C-14 is also included in this category. C-14 exhibits a capacity to concentrate in bone. C-14 is released in gaseous form and is absorbed into vegetation through photosynthesis. The principal pathways of interest for C-14 are the consumption of vegetation by humans and milk from which animals have ingested C-14 through the consumption of vegetation. With the requirement to begin reporting C-14 dose in 2011 and the addition of C-14 to plant effluents, human dose in this category is primarily driven by the release of C-14 from the plant.

The hypothetical dose to the maximum exposed individual living near the station via ingestion of milk and vegetation was calculated. The source of milk and vegetation was assumed to be at the nearest site boundary with the cows pastured and vegetation grown from May through October. The maximum dose from radioactive iodine and particulate (including C-14) to any organ was 7.26E-01 mrem (child/bone) based on measured effluents and average meteorological data and 6.84E-01 mrem based on measured effluents and concurrent meteorological data.

The maximum dose from radioactive iodine and particulate (including C-14) to the whole body was 1.48E-01 mrem (child) based on measured effluents and average meteorological data and 1.40E-01 mrem (child) based on measured effluents and concurrent meteorological data.

3.1.3 Gaseous Total Dose The maximum total dose from gaseous releases to any organ was 7.26E-01 mrem (child/bone) based on measured effluents and average meteorological data, and 6.84E-01 mrem (child/bone) based on measured effluents and concurrent meteorological data.

The maximum total dose from gaseous releases to the whole body was 1.48E-01 mrem (child) based on measured effluents and average meteorological data, and 1.40E-01 mrem (child) based on measured effluents and concurrent meteorological data.

3.2 Liquid Effluent Pathways The principal pathways through the aquatic environment for potential doses to man from liquid waste are ingestion of potable water and eating aquatic foods. Liquid dose was calculated based on the ingestion of potable water and sport fish. It should be noted, however, there were no communities within 10 km downstream of the plant using the Rock River for drinking water. NRC-developed equations were used to calculate the doses to the whole body, bone, liver, thyroid, kidney, lung, lower GI tract, and skin. Specific parameters for use in the equations are given in the Exelon Offsite Dose Calculation Manual (ODCM).

The maximum dose from liquid releases to any organ was 6.74E-01 E-6

mrem (Child/bone). The maximum dose from liquid releases to the whole body was 2.83E-01 mrem (adult).

3.3 Gaseous + Liquid Total Dose The maximum total dose to any organ via both gaseous and liquid effluents to any organ is 1.40E+00 mrem (child/bone). The maximum dose to the whole body via both gaseous and liquid effluents is 3.26E-01 mrem (child).

3.4 Dose Limits to Members of the Public Byron Station did not exceed any of the dose limits as shown below based on concurrent or historical meteorological data.

The limits on dose or dose commitment to a member of the public due to radioactive materials in liquid effluents from each reactor is 1.5 mrem to the whole body or 5 mrem to any organ during any calendar quarter and 3 mrem to the whole body or 10 mrem to any organ during a calendar year.

The limits on air dose in noble gases released in gaseous effluents to a member of the public from each reactor is 5 mrad for gamma radiation or 10 mrad for beta radiation during any calendar quarter and 10 mrad for gamma radiation or 20 mrad for beta radiation during a calendar year.

The limits on dose to a member of the public due to radioactive iodine

& particulate with half-lives greater than eight days in gaseous effluents released from each reactor is 7.5 mrem to any organ during any calendar quarter and 15 mrem during a calendar year.

The annual 10CFR20 limit on Total Effective Dose Equivalent to individual members of the public is 100 mrem.

The 40CFR190 limits on individual members of the public is 25 mrem to the whole body, 25 mrem to any organ (except thyroid), and 75 mrem to the thyroid.

4.0 SITE METEOROLOGY Detailed records of the site meteorological measurements taken during each calendar quarter of the year are maintained by the meteorological vendor, retained on site, and are available upon request. The data are presented as cumulative joint frequency distributions of the wind direction for the 250 level and wind speed class by atmospheric stability class determined from the temperature difference between the 250 and 30 levels. Data recovery for all measurements on the meteorological tower was 99.7% during 2020.

E-7

Intentionally left blank APPENDIX E-1 DATA TABLES AND FIGURES

Intentionally left blank Table 1.1-1 RG 1.21 EFFLUENT AND WASTE DISPOSAL REPORT GASEOUS EFFLUENTS - SUMMATION OF ALL RELEASES Unit 1 REPORT FOR 2020 Units QTR 1 QTR 2 QTR 3 QTR 4 YEAR Fission and Activation Gases

1. Total Release Ci 2.95E+00 2.15E-01 9.06E-02 7.86E-02 3.33E+00

2. Avg. Release Rate uCi/sec 3.75E-01 2.73E-02 1.14E-02 9.89E-01 1.05E-01 Iodine-131

1. Total Release Ci (1) (1) (1) (1) (1)

2. Avg. Release Rate uCi/sec (1) (1) (1) (1) (1)

Particulates Half Life >= 8 days

1. Total Release Ci 2.74E-05 2.45E-05 (1) 3.22E-05 8.41E-05

2. Avg. Release Rate uCi/sec 3.49E-06 3.11E-06 (1) 4.06E-06 2.66E-06 Others

1. Total Release Ci 8.02E-01 1.18E+00 1.12E+00 1.44E+00 4.55E+00

2. Avg. Release Rate uCi/sec 1.02E-01 1.50E-01 1.41E-01 1.81E-01 1.44E-01 Tritium

1. Total Release Ci 2.61E+00 1.91E+00 1.98E+00 3.06E+00 9.57E+00

2. Avg. Release Rate uCi/sec 3.32E-01 2.43E-01 2.50E-01 3.85E-01 3.03E-01 Gross Alpha Radioactivity

1. Total Release Ci (1) (1) (1) (1) (1)

2. Avg. Release Rate uCi/sec (1) (1) (1) (1) (1)

(1) Less than minimum detectable activity which meets the lower limit of detection (LLD) requirements of TRM Section 3.11 E-1-1

Table 1.1-1 (cont.)

RG 1.21 EFFLUENT AND WASTE DISPOSAL REPORT GASEOUS EFFLUENTS - SUMMATION OF ALL RELEASES Unit 2 REPORT FOR 2020 Units QTR 1 QTR 2 QTR 3 QTR 4 YEAR Fission and Activation Gases

1. Total Release Ci 9.48E-02 1.63E-01 8.48E-02 1.90E-01 5.32E-01

2. Avg. Release Rate uCi/sec 1.21E-02 2.07E-02 1.07E-02 2.39E-02 1.68E-02 Iodine-131

1. Total Release Ci 1.48E-06 (1) (1) (1) 1.48E-06

2. Avg. Release Rate uCi/sec 1.88E-07 (1) (1) (1) 4.67E-08 Particulates Half Life >= 8 days

1. Total Release Ci 1.05E-05 8.72E-06 (1) 4.66E-05 6.58E-05

2. Avg. Release Rate uCi/sec 1.33E-06 1.11E-06 (1) 5.87E-06 2.08E-06 Others

1. Total Release Ci 1.21E+00 1.10E+00 1.18E+00 8.77E-01 4.36E+00

2. Avg. Release Rate uCi/sec 1.54E-01 1.40E-01 1.48E-01 1.10E-01 1.38E-01 Tritium

1. Total Release Ci 1.15E+01 7.13E+00 9.28E+00 1.03E+01 3.82E+01

2. Avg. Release Rate uCi/sec 1.47E+00 9.07E-01 1.17E+00 1.29E+00 1.21E+00 Gross Alpha Radioactivity

1. Total Release Ci (1) (1) (1) (1) (1)

2. Avg. Release Rate uCi/sec (1) (1) (1) (1) (1)

(1) Less than minimum detectable activity which meets the lower limit of detection (LLD) requirements of TRM Section 3.11 E-1-2

Table 1.2-1 RG 1.21 EFFLUENT AND WASTE DISPOSAL REPORT LIQUID EFFLUENTS - SUMMATION OF ALL RELEASES Unit 1 REPORT FOR 2020 Units QTR 1 QTR 2 QTR 3 QTR 4 YEAR Fission and Activation Products

1. Total Release Ci 1.10E-02 9.42E-03 1.21E-02 1.86E-02 5.11E-02

2. Avg. Diluted Conc. uCi/ml 3.60E-09 2.63E-09 3.11E-09 5.12E-09 3.61E-09 Tritium

1. Total Release Ci 5.98E+02 2.11E+02 4.52E+02 1.44E+02 1.40E+03

2. Avg. Diluted Conc. uCi/ml 1.96E-04 5.88E-05 1.16E-04 3.97E-05 9.92E-05 Dissolved and Entrained Gases

1. Total Release Ci 2.60E-04 8.59E-06 2.18E-04 1.32E-05 4.99E-04

2. Avg. Diluted Conc. uCi/ml 8.50E-11 2.39E-12 5.60E-11 3.65E-12 3.53E-11 Gross Alpha Radioactivity

1. Total Release Ci (1) (1) (1) (1) (1)

Volume of liquid waste liters 3.05E+09 3.59E+09 3.90E+09 3.63E+09 1.42E+10 Volume of dil. water liters (1) (1) (1) (1) (1)

(1) Less than minimum detectable activity which meets the lower limit of detection (LLD) requirements of TRM Section 3.11 E-1-3

Table 1.2-1 (cont.)

RG 1.21 EFFLUENT AND WASTE DISPOSAL REPORT LIQUID EFFLUENTS - SUMMATION OF ALL RELEASES Unit 2 REPORT FOR 2020 Units QTR 1 QTR 2 QTR 3 QTR 4 YEAR Fission and Activation Products

1. Total Release Ci 1.10E-02 9.42E-03 1.21E-02 1.86E-02 5.11E-02

2. Avg. Diluted Conc. uCi/ml 3.60E-09 2.63E-09 3.11E-09 5.12E-09 3.61E-09 Tritium

1. Total Release Ci 5.98E+02 2.11E+02 4.52E+02 1.44E+02 1.40E+03

2. Avg. Diluted Conc. uCi/ml 1.96E-04 5.88E-05 1.16E-04 3.97E-05 9.92E-05 Dissolved and Entrained Gases

1. Total Release Ci 2.60E-04 8.59E-06 2.18E-04 1.32E-05 4.99E-04

2. Avg. Diluted Conc. uCi/ml 8.50E-11 2.39E-12 5.60E-11 3.65E-12 3.53E-11 Gross Alpha Radioactivity

1. Total Release Ci (1) (1) (1) (1) (1)

Volume of liquid waste liters 3.05E+09 3.59E+09 3.90E+09 3.63E+09 1.42E+10 Volume of dil. water liters (1) (1) (1) (1) (1)

(1) Less than minimum detectable activity which meets the lower limit of detection (LLD) requirements of TRM Section 3.11 E-1-4

Table 3.1-1 40CFR190 URANIUM FUEL CYCLE DOSE REPORT LIQUID DOSE

SUMMARY

Units 1 & 2 Report for: 2020 Unit Range - From: 1 To: 2 Liquid Receptor PERIOD DOSE BY ORGAN AND AGE GROUP (mrem) ANNUAL 2020 Age Grp Bone Liver Thyroid Kidney Lung GI-LLI Skin TB ADULT 4.96E-01 3.65E-01 1.36E-01 2.25E-01 1.57E-01 4.24E-01 0.00E+00 2.83E-01 TEEN 5.19E-01 3.42E-01 1.02E-01 1.73E-01 1.29E-01 3.07E-01 0.00E+00 1.92E-01 CHILD 6.74E-01 3.32E-01 1.14E-01 1.75E-01 1.35E-01 1.88E-01 0.00E+00 1.64E-01 INFANT 2.78E-03 5.02E-02 4.99E-02 4.99E-02 4.99E-02 5.00E-02 0.00E+00 5.00E-02 SITE DOSE LIMIT ANALYSIS ANNUAL 2020 Age Dose Limit Max % of Annual - Limit Group Organ (mrem) (mrem) Limit 2020 - Admin. Any Organ CHILD BONE 6.74E-01 7.50E+00 8.99E+00 2020 - Admin. Total Body ADULT TBODY 2.83E-01 2.25E+00 1.26E+01 2020 - T.Spc. Any Organ CHILD BONE 6.74E-01 1.00E+01 6.74E+00 Critical Pathway: Fresh Major Contributors (0% or greater to total)

Nuclide Percentage FE-55 2.76E-01 FE-59 7.32E-03 NI-63 6.95E+01 ZN-65 1.18E-01 SR-89 2.48E-01 ZR-95 3.15E-06 NB-95 1.10E-02 NB-97 2.24E-06 AG-110M 2.14E-06 SB-124 1.48E-05 SB-125 1.18E-03 TE-125M 1.08E+00 TE-132 8.20E-03 I-132 4.93E-05 CS-134 2.24E-01 CS-137 2.85E+01 2020 - T.Spc. Total Body ADULT TBODY 2.83E-01 3.00E+00 9.43E+00 Critical Pathway: Fresh E-1-5

Table 3.1-1 (cont.)

40CFR190 URANIUM FUEL CYCLE DOSE REPORT LIQUID DOSE

SUMMARY

Units 1 & 2 Major Contributors (0% or greater to total)

Nuclide Percentage H-3 4.75E+01 CR-51 7.85E-04 MN-54 1.30E-01 MN-56 1.67E-05 FE-55 7.69E-02 FE-59 1.25E-02 CO-58 6.59E-01 CO-60 9.10E-01 NI-63 4.07E+00 ZN-65 4.36E-01 SR-89 1.19E-02 ZR-95 1.18E-06 NB-95 6.59E-03 NB-97 9.89E-07 AG-110M 2.20E-06 SB-124 8.32E-06 SB-125 3.93E-04 TE-125M 2.46E-01 TE-132 9.00E-03 I-132 8.28E-05 CS-134 8.40E-01 CS-137 4.51E+01 E-1-6

Table 3.2-1 40CFR190 URANIUM FUEL CYCLE DOSE REPORT GASEOUS DOSE

SUMMARY

Units 1 & 2 Report for: 2020 Unit Range - From: 1 To: 2 I&P DOSE LIMIT ANALYSIS ANNUAL 2020 Age Dose Limit Max % of Annual - Limit Group Organ (mrem) (mrem) Limit 2020 - Admin. Any Organ CHILD BONE 7.26E-01 1.13E+01 6.45E+00 2020 - Admin. Total Body CHILD TBODY 1.48E-01 1.05E+01 1.41E+00 2020 - T.Spc. Any Organ CHILD BONE 7.26E-01 1.50E+01 4.84E+00 Receptor: Composite Crit. Receptor - IP Distance: 0.00 (meters) Compass Point: SNA Critical Pathway: Vegetation Major Contributors (0% or greater to total)

Nuclide Percentage H-3 0.00E+00 C-14 1.00E+02 CO-58 1.30E-04 CO-60 4.56E-02 I-131 3.60E-05 2020 - T.Spc. Total Body CHILD TBODY 1.48E-01 1.50E+01 9.88E-01 Receptor: Composite Crit. Receptor - IP Distance: 0.00 (meters) Compass Point: NA Critical Pathway: Vegetation Major Contributors (0% or greater to total)

Nuclide Percentage H-3 1.82E+00 C-14 9.79E+01 CO-58 1.11E-03 CO-60 2.39E-01 I-131 1.02E-04 E-1-7

Table 3.2-1 (cont.)

40CFR190 URANIUM FUEL CYCLE DOSE REPORT GASEOUS DOSE

SUMMARY

Units 1 & 2 Report for: 2020 Unit Range - From: 1 To: 2 NG DOSE LIMIT ANALYSIS ANNUAL 2020 Dose Limit Max % of Annual - Limit (mrad) (mrad) Limit 2020 - Admin. Gamma 2.84E-04 7.50E+00 3.78E-03 2020 - Admin. Beta 6.86E-05 1.50E+01 4.58E-04 2020 - T.Spc. Gamma 2.84E-04 1.00E+01 2.84E-03 Receptor: 4 Composite Crit. Receptor - NG Distance: 0.00 (meters) Compass Point: NA Nuclide Percentage AR-41 7.58E+01 KR-85M 1.37E-03 XE-135 1.52E-01 XE-133M 3.50E-03 KR-88 8.85E-03 XE-131M 6.73E-04 XE-133 2.40E+01 2020 - T.Spc. Beta 6.86E-05 2.00E+01 3.43E-04 Receptor: 4 Composite Crit. Receptor - NG Distance: 0.00 (meters) Compass Point: NA Nuclide Percentage AR-41 2.72E+01 KR-85M 2.22E-03 XE-135 1.97E-01 XE-133M 1.61E-02 KR-88 1.73E-03 XE-131M 4.86E-03 XE-133 7.26E+01 E-1-8

Table 3.3-1 40CFR190 URANIUM FUEL CYCLE DOSE REPORT Units 1 & 2 Report for: 2020 Unit Range - From: 1 To: 2 MAXIMUM DOSE ANALYSIS ANNUAL 2020 Age Dose Dose Type Group Organ (mrem)

Any Organ CHILD BONE 1.40E+00 Liquid Receptor: Liquid Receptor Gaseous Receptor: 5 Composite Crit. Receptor - IP Distance: 0.00 (meters) Compass Point: NA Liquid Dose: 6.74E-01 % of Total: 4.81E+01 Critical Pathway: Fresh Water Fish - Sport (FFSP)

Major Contributors (0% or greater to total)

Nuclide Percentage H-3 0.00E+00 CR-51 0.00E+00 MN-54 0.00E+00 MN-56 0.00E+00 FE-55 2.76E-01 FE-59 7.32E-03 CO-58 0.00E+00 CO-60 0.00E+00 NI-63 6.95E+01 ZN-65 1.18E-01 SR-89 2.48E-01 ZR-95 3.15E-06 NB-95 1.10E-02 NB-97 2.24E-06 AG-110M 2.14E-06 SB-124 1.48E-05 SB-125 1.18E-03 TE-125M 1.08E+00 TE-132 8.20E-03 I-132 4.93E-05 CS-134 2.24E-01 CS-137 2.85E+01 Gaseous Dose: 7.26E-01 % of Total: 5.19E+01 Critical Pathway: Vegetation (VEG)

Major Contributors (0% or greater to total)

Nuclide Percentage H-3 0.00E+00 C-14 1.00E+02 CO-58 1.30E-04 CO-60 4.56E-02 I-131 3.60E-05 E-1-9

Table 3.3-1 (cont.)

40CFR190 URANIUM FUEL CYCLE DOSE REPORT Units 1 & 2 MAXIMUM DOSE ANALYSIS ANNUAL 2020 Age Dose Dose Type Group Organ (mrem)

Total Body CHILD TBODY 3.26E-01 Liquid Receptor: Liquid Receptor Gaseous Receptor: 5 Composite Crit. Receptor - IP Distance: 0.00 (meters) Compass Point: NA Liquid Dose: 2.83E-01 % of Total: 8.68E+01 Critical Pathway: Fresh Water Fish - Sport (FFSP)

Major Contributors (0% or greater to total)

Nuclide Percentage H-3 4.75E+01 CR-51 7.85E-04 MN-54 1.30E-01 MN-56 1.67E-05 FE-55 7.69E-02 FE-59 1.25E-02 CO-58 6.59E-01 CO-60 9.10E-01 NI-63 4.07E+00 ZN-65 4.36E-01 SR-89 1.19E-02 ZR-95 1.18E-06 NB-95 6.59E-03 NB-97 9.89E-07 AG-110M 2.20E-06 SB-124 8.32E-06 SB-125 3.93E-04 TE-125M 2.46E-01 TE-132 9.00E-03 I-132 8.28E-05 CS-134 8.40E-01 CS-137 4.51E+01 Gaseous Dose: 4.30E-02 % of Total: 1.32E+01 Critical Pathway: Vegetation (VEG)

Major Contributors (0% or greater to total)

Nuclide Percentage H-3 4.16E+00 C-14 9.50E+01 CO-58 2.89E-03 CO-60 7.91E-01 I-131 1.38E-04 E-1-10

Table 3.4-1 The following are the maximum annual calculated cumulative offsite doses resulting from Byron airborne releases in 2020 based on concurrent meteorological data:

Unit 1:

Dose Maximum Value Sector Affected gamma air (1) 3.32 x10-5 mrad East-Southeast beta air (2) 4.20 x10-5 mrad East-Southeast whole body (3) 7.06 x10-2 mrem East-Southeast skin (4) 4.21 x10-5 mrem East-Southeast organ (5) (child-bone) 3.49 x10-1 mrem East-Southeast Unit 1 Compliance Status 10 CFR 50 Appendix I Yearly Objective % of Appendix I gamma air 10.0 mrad 0.00 beta air 20.0 mrad 0.00 whole body 5.0 mrem 1.41 skin 15.0 mrem 0.00 organ 15.0 mrem 2.33 Unit 2:

Dose Maximum Value Sector Affected gamma air (1) 2.93 x10-5 mrad East-Southeast beta air (2) 1.26 x10-5 mrad East-Southeast whole body (3) 6.94 x10-2 mrem East-Southeast skin (4) 3.17 x10-5 mrem East-Southeast organ (5) (child-bone) 3.35 x10-1 mrem East-Southeast Unit 2 Compliance Status 10 CFR 50 Appendix I Yearly Objective % of Appendix I gamma air 10.0 mrad 0.00 beta air 20.0 mrad 0.00 whole body 5.0 mrem 1.39 skin 15.0 mrem 0.00 organ 15.0 mrem 2.23 (1) Gamma Air Dose - GASPAR II, NUREG-0597 (2) Beta Air Dose - GASPAR II, NUREG-0597 (3) Whole Body Dose - GASPAR II, NUREG-0597 (4) Skin Dose - GASPAR II, NUREG-0597 (5) Inhalation and Food Pathways Dose - GASPAR II, NUREG-0597 Data recovery: 99.7%

E-1-11

Intentionally left blank APPENDIX F METEOROLOGICAL DATA

Intentionally left blank Byron Generating Station Period of Record: January - March 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 4 0 0 0 4 SSE 0 0 3 1 0 0 4 S 0 0 2 1 0 0 3 SSW 0 2 0 0 0 0 2 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 2 9 2 0 0 13 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 S 0 1 0 0 0 0 1 SSW 0 0 1 0 0 0 1 SW 0 0 0 0 0 0 0 WSW 0 0 1 0 0 0 1 W 1 0 0 0 0 0 1 WNW 0 0 0 0 0 0 0 NW 1 1 1 0 0 0 3 NNW 0 1 0 1 0 0 2 Variable 0 0 0 0 0 0 0 Total 2 3 3 1 0 0 9 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 1 0 0 0 1 NE 0 0 0 0 0 0 0 ENE 0 1 0 0 0 0 1 E 0 1 0 0 0 0 1 ESE 0 0 1 0 0 0 1 SE 0 0 0 0 0 0 0 SSE 0 0 2 0 0 0 2 S 0 1 1 0 0 0 2 SSW 0 0 1 0 0 0 1 SW 0 0 0 0 0 0 0 WSW 0 1 1 0 0 0 2 W 0 0 0 2 0 0 2 WNW 0 0 0 1 0 0 1 NW 1 2 2 0 0 0 5 NNW 0 1 4 1 0 0 6 Variable 0 0 0 0 0 0 0 Total 1 7 12 4 0 0 24 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 21 49 51 0 0 122 NNE 5 28 22 32 0 0 87 NE 9 25 26 1 0 0 61 ENE 3 29 31 0 0 0 63 E 5 29 6 0 0 0 40 ESE 3 24 26 12 0 0 65 SE 0 18 19 13 0 0 50 SSE 3 23 39 13 0 0 78 S 2 34 39 23 1 0 99 SSW 4 23 15 13 4 0 59 SW 1 23 25 9 0 0 58 WSW 3 17 32 10 2 0 64 W 10 26 64 25 14 3 142 WNW 7 37 47 48 6 0 145 NW 1 66 42 34 0 0 143 NNW 3 28 48 28 6 0 113 Variable 0 0 0 0 0 0 0 Total 60 451 530 312 33 3 1389 Hours of calm in this stability class: 1 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 4 6 1 0 0 0 11 NNE 3 7 14 1 0 0 25 NE 3 7 8 2 0 0 20 ENE 1 4 7 1 0 0 13 E 6 13 1 0 0 0 20 ESE 5 15 11 8 3 0 42 SE 2 10 3 3 0 0 18 SSE 2 16 27 9 0 0 54 S 3 14 36 29 1 0 83 SSW 7 3 19 19 0 0 48 SW 9 28 21 9 0 0 67 WSW 4 26 5 5 1 0 41 W 11 30 19 8 0 0 68 WNW 7 30 17 10 1 0 65 NW 5 31 8 5 1 0 50 NNW 5 15 5 0 0 0 25 Variable 0 0 0 0 0 0 0 Total 77 255 202 109 7 0 650 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 3 0 0 0 0 3 NNE 2 1 0 0 0 0 3 NE 0 0 1 0 0 0 1 ENE 0 0 0 0 0 0 0 E 0 4 0 0 0 0 4 ESE 0 5 2 0 0 0 7 SE 0 6 0 0 0 0 6 SSE 0 7 3 2 0 0 12 S 2 6 1 0 0 0 9 SSW 1 1 0 0 0 0 2 SW 1 1 0 0 0 0 2 WSW 4 3 0 0 0 0 7 W 5 3 0 0 0 0 8 WNW 5 2 0 0 0 0 7 NW 4 4 0 0 0 0 8 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 24 46 7 2 0 0 79 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 2 0 0 0 0 2 SSE 0 0 1 0 0 0 1 S 0 1 0 0 0 0 1 SSW 3 0 0 0 0 0 3 SW 1 0 0 0 0 0 1 WSW 3 0 0 0 0 0 3 W 2 0 0 0 0 0 2 WNW 1 0 0 0 0 0 1 NW 1 0 0 0 0 0 1 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 11 3 1 0 0 0 15 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 3 1 0 4 SSE 0 0 0 3 1 0 4 S 0 0 3 1 0 0 4 SSW 0 1 0 0 0 0 1 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 1 3 7 2 0 13 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 S 0 0 2 0 0 0 2 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 1 0 0 1 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 1 2 0 0 0 3 NNW 0 1 1 1 0 0 3 Variable 0 0 0 0 0 0 0 Total 0 2 5 2 0 0 9 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 1 0 0 0 1 E 0 0 1 0 0 0 1 ESE 0 0 0 1 0 0 1 SE 0 0 0 0 0 0 0 SSE 0 0 0 1 1 0 2 S 0 1 0 1 0 0 2 SSW 0 0 0 0 1 0 1 SW 0 0 0 0 0 0 0 WSW 0 0 2 0 0 0 2 W 0 0 0 0 2 0 2 WNW 0 0 0 1 0 0 1 NW 0 0 4 1 0 0 5 NNW 0 2 1 3 0 0 6 Variable 0 0 0 0 0 0 0 Total 0 3 9 8 4 0 24 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 6 29 22 19 0 77 NNE 0 21 20 26 30 1 98 NE 3 14 17 20 2 0 56 ENE 1 9 28 22 2 0 62 E 2 7 27 11 1 0 48 ESE 1 6 10 31 12 3 63 SE 1 5 7 13 8 4 38 SSE 2 9 12 24 7 3 57 S 1 15 28 24 30 2 100 SSW 1 9 21 8 12 4 55 SW 0 11 19 23 10 2 65 WSW 1 6 28 12 4 4 55 W 2 11 33 51 12 22 131 WNW 3 16 31 49 32 4 135 NW 3 39 49 45 19 0 155 NNW 2 19 25 39 19 6 110 Variable 0 0 0 0 0 0 0 Total 24 203 384 420 219 55 1305 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 85 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 4 8 5 0 0 18 NNE 2 6 6 2 8 0 24 NE 1 2 6 6 9 0 24 ENE 2 3 4 3 6 0 18 E 2 3 3 4 1 0 13 ESE 1 3 9 8 11 6 38 SE 0 2 10 7 2 2 23 SSE 0 1 10 5 10 8 34 S 0 0 9 23 28 28 88 SSW 0 2 6 11 29 11 59 SW 1 4 17 17 18 4 61 WSW 0 0 19 17 7 1 44 W 2 3 22 36 7 2 72 WNW 1 3 18 20 9 2 53 NW 0 1 25 25 6 1 58 NNW 0 4 12 7 0 0 23 Variable 0 0 0 0 0 0 0 Total 13 41 184 196 151 65 650 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 1 4 0 0 5 NNE 0 0 0 1 1 0 2 NE 0 1 1 0 0 0 2 ENE 0 0 1 1 0 0 2 E 0 0 1 0 0 0 1 ESE 1 0 0 7 1 0 9 SE 0 0 1 4 1 0 6 SSE 0 0 0 3 0 1 4 S 0 0 0 4 3 1 8 SSW 0 0 0 4 2 0 6 SW 0 1 2 2 0 0 5 WSW 0 0 0 3 0 0 3 W 1 1 2 4 0 0 8 WNW 0 0 5 0 0 0 5 NW 0 1 2 2 0 0 5 NNW 0 0 5 3 0 0 8 Variable 0 0 0 0 0 0 0 Total 2 4 21 42 8 2 79 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: January - March 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 1 0 0 1 S 0 0 1 0 1 0 2 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 3 0 0 0 3 W 0 0 1 0 0 0 1 WNW 0 0 4 0 0 0 4 NW 0 0 2 0 0 0 2 NNW 0 0 1 1 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 0 12 2 1 0 15 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 4

Byron Generating Station Period of Record: April - June 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 7 0 0 0 0 7 NNE 0 5 0 0 0 0 5 NE 0 2 0 0 0 0 2 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 1 0 0 0 1 SSE 0 3 2 0 0 0 5 S 0 0 1 1 0 0 2 SSW 0 0 1 0 0 0 1 SW 0 2 0 0 0 0 2 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 1 0 0 0 1 NW 0 0 1 0 0 0 1 NNW 0 0 2 0 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 19 9 1 0 0 29 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 1 0 0 0 1 E 0 0 2 0 0 0 2 ESE 0 0 0 0 0 0 0 SE 0 1 0 0 0 0 1 SSE 0 0 0 1 0 0 1 S 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 1 1 0 2 W 0 0 1 2 1 0 4 WNW 0 0 0 1 0 0 1 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 1 4 5 2 0 12 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 2 0 0 0 2 ENE 0 0 2 0 0 0 2 E 0 0 7 0 0 0 7 ESE 0 1 7 0 0 0 8 SE 0 1 2 4 0 0 7 SSE 0 1 2 4 1 0 8 S 0 0 1 1 0 0 2 SSW 0 2 0 0 0 0 2 SW 0 2 3 4 2 0 11 WSW 0 0 0 2 0 0 2 W 0 2 2 5 0 0 9 WNW 0 1 6 1 2 0 10 NW 0 0 6 4 0 0 10 NNW 0 1 0 0 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 11 40 25 5 0 81 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 3 14 25 17 5 0 64 NNE 2 23 17 6 0 0 48 NE 3 14 25 11 0 0 53 ENE 3 14 27 1 0 0 45 E 4 19 45 0 0 0 68 ESE 2 19 24 8 0 0 53 SE 2 11 28 12 5 0 58 SSE 1 16 44 18 1 0 80 S 2 19 41 9 1 0 72 SSW 1 20 17 13 4 0 55 SW 1 30 13 7 3 0 54 WSW 2 15 21 11 2 0 51 W 4 22 37 13 1 0 77 WNW 1 19 41 31 7 0 99 NW 1 21 57 23 12 1 115 NNW 2 12 25 30 4 0 73 Variable 0 0 0 0 0 0 0 Total 34 288 487 210 45 1 1065 Hours of calm in this stability class: 1 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 7 15 5 0 0 0 27 NNE 2 3 7 1 0 0 13 NE 2 5 10 2 0 0 19 ENE 6 12 21 6 0 0 45 E 3 55 11 0 0 0 69 ESE 7 21 26 0 2 0 56 SE 7 27 29 1 2 0 66 SSE 1 26 25 2 0 0 54 S 9 24 19 0 0 0 52 SSW 12 10 11 2 0 0 35 SW 12 26 10 5 0 0 53 WSW 11 12 17 1 0 0 41 W 10 36 14 2 0 0 62 WNW 4 23 16 8 0 0 51 NW 5 23 10 0 0 0 38 NNW 6 17 9 6 1 0 39 Variable 0 0 0 0 0 0 0 Total 104 335 240 36 5 0 720 Hours of calm in this stability class: 1 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 5 0 0 0 0 5 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 15 0 0 0 0 15 ESE 4 25 20 0 0 0 49 SE 5 31 9 0 0 0 45 SSE 1 11 3 0 0 0 15 S 9 7 1 0 0 0 17 SSW 12 1 0 0 0 0 13 SW 3 1 0 0 0 0 4 WSW 8 0 0 0 0 0 8 W 7 2 0 0 0 0 9 WNW 11 3 0 0 0 0 14 NW 7 9 0 0 0 0 16 NNW 2 11 0 0 0 0 13 Variable 0 0 0 0 0 0 0 Total 69 121 33 0 0 0 223 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 3 0 0 0 0 3 ESE 0 5 8 0 0 0 13 SE 2 6 0 0 0 0 8 SSE 1 4 0 0 0 0 5 S 3 2 0 0 0 0 5 SSW 3 1 0 0 0 0 4 SW 0 0 0 0 0 0 0 WSW 2 0 0 0 0 0 2 W 3 0 0 0 0 0 3 WNW 2 0 0 0 0 0 2 NW 2 1 0 0 0 0 3 NNW 1 0 0 0 0 0 1 Variable 0 0 0 0 0 0 0 Total 19 22 8 0 0 0 49 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 2 1 0 0 0 3 NNE 0 2 7 0 0 0 9 NE 0 1 1 0 0 0 2 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 1 0 2 0 0 3 S 0 0 1 3 1 0 5 SSW 0 0 0 1 0 0 1 SW 0 1 0 1 0 0 2 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 1 0 0 0 1 NW 0 0 0 1 0 0 1 NNW 0 0 0 2 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 7 11 10 1 0 29 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 1 0 0 0 1 E 0 0 2 0 0 0 2 ESE 0 0 0 0 0 0 0 SE 0 0 1 0 0 0 1 SSE 0 0 0 0 0 1 1 S 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 1 0 1 2 W 0 0 0 1 2 1 4 WNW 0 0 0 0 1 0 1 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 4 2 3 3 12 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 4 0 0 0 4 E 0 0 6 1 0 0 7 ESE 0 0 6 2 0 0 8 SE 0 0 2 3 2 0 7 SSE 0 0 2 3 1 1 7 S 0 0 0 2 1 0 3 SSW 0 0 1 0 0 0 1 SW 0 0 3 3 3 3 12 WSW 0 1 0 2 0 0 3 W 0 0 1 7 2 0 10 WNW 0 0 1 6 1 2 10 NW 0 0 1 3 4 0 8 NNW 0 0 1 0 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 1 28 32 14 6 81 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 10 19 9 11 3 52 NNE 0 12 15 16 7 0 50 NE 2 6 21 19 5 0 53 ENE 1 8 19 21 2 0 51 E 3 6 26 33 0 0 68 ESE 2 3 29 10 8 1 53 SE 3 5 12 20 7 5 52 SSE 0 8 34 33 11 3 89 S 1 7 31 16 7 3 65 SSW 0 14 17 14 10 4 59 SW 1 16 17 9 6 8 57 WSW 0 11 18 12 10 2 53 W 1 9 33 27 6 3 79 WNW 0 9 24 41 19 9 102 NW 0 11 36 40 10 11 108 NNW 3 3 22 24 12 11 75 Variable 0 0 0 0 0 0 0 Total 17 138 373 344 131 63 1066 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 7 6 11 0 1 26 NNE 1 4 3 10 1 0 19 NE 1 2 8 3 1 0 15 ENE 0 2 4 22 13 0 41 E 0 8 26 26 4 0 64 ESE 0 3 8 23 11 2 47 SE 0 3 12 27 15 3 60 SSE 0 2 14 31 12 1 60 S 2 4 6 21 9 0 42 SSW 3 6 17 11 8 0 45 SW 1 3 22 12 12 2 52 WSW 0 5 21 18 0 0 44 W 1 8 22 35 2 0 68 WNW 1 4 18 20 11 0 54 NW 1 6 27 12 0 0 46 NNW 2 6 12 11 5 2 38 Variable 0 0 0 0 0 0 0 Total 14 73 226 293 104 11 721 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 8 9 0 0 17 NNE 0 0 1 1 0 0 2 NE 0 0 0 0 0 0 0 ENE 1 0 0 0 0 0 1 E 0 3 3 3 1 0 10 ESE 0 0 8 7 13 0 28 SE 0 1 6 26 10 0 43 SSE 0 1 4 18 4 0 27 S 0 0 5 5 2 0 12 SSW 0 1 8 3 0 0 12 SW 0 2 7 6 0 0 15 WSW 0 3 2 1 0 0 6 W 0 1 5 5 0 0 11 WNW 0 2 5 3 0 0 10 NW 0 1 6 5 0 0 12 NNW 0 1 7 9 0 0 17 Variable 0 0 0 0 0 0 0 Total 1 16 75 101 30 0 223 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: April - June 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 1 0 0 1 NNE 1 0 0 0 0 0 1 NE 0 0 0 0 0 0 0 ENE 0 1 0 0 0 0 1 E 0 0 0 0 0 0 0 ESE 0 1 1 1 6 0 9 SE 0 0 0 4 2 0 6 SSE 0 0 3 2 0 0 5 S 0 1 1 2 1 0 5 SSW 0 0 5 2 0 0 7 SW 0 1 1 3 0 0 5 WSW 0 0 1 0 0 0 1 W 0 0 4 0 0 0 4 WNW 0 0 2 0 0 0 2 NW 0 0 1 1 0 0 2 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 1 4 19 16 9 0 49 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 1 0 0 1 S 0 2 0 0 0 0 2 SSW 0 0 2 0 0 0 2 SW 0 1 1 0 0 0 2 WSW 0 0 2 0 0 0 2 W 0 0 6 0 0 0 6 WNW 0 1 1 0 0 0 2 NW 0 1 4 0 0 0 5 NNW 0 0 2 0 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 5 18 1 0 0 24 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 1 0 0 0 1 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 2 0 0 0 0 2 SE 0 1 0 0 0 0 1 SSE 0 1 2 0 0 0 3 S 0 0 5 0 0 0 5 SSW 0 1 4 0 0 0 5 SW 0 1 6 0 0 0 7 WSW 0 0 1 0 0 0 1 W 0 1 3 0 0 0 4 WNW 0 0 0 4 0 0 4 NW 0 2 5 0 0 0 7 NNW 0 0 1 0 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 9 28 4 0 0 41 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 1 1 0 0 0 2 NNE 0 1 1 0 0 0 2 NE 0 1 1 0 0 0 2 ENE 0 1 0 0 0 0 1 E 0 1 0 0 0 0 1 ESE 0 0 0 0 0 0 0 SE 0 3 0 0 0 0 3 SSE 0 3 1 0 0 0 4 S 0 3 6 1 0 0 10 SSW 0 2 9 0 0 0 11 SW 0 6 3 0 0 0 9 WSW 0 3 4 0 0 0 7 W 0 3 5 0 0 0 8 WNW 0 1 2 0 0 0 3 NW 0 1 2 0 0 0 3 NNW 0 1 1 0 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 31 36 1 0 0 68 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 24 57 0 0 0 82 NNE 2 18 28 4 0 0 52 NE 3 21 11 1 0 0 36 ENE 7 22 15 0 0 0 44 E 13 25 1 0 0 0 39 ESE 7 28 3 0 0 0 38 SE 6 14 11 0 0 0 31 SSE 1 24 28 1 0 0 54 S 4 38 45 8 0 0 95 SSW 2 23 16 1 0 0 42 SW 3 47 19 2 0 0 71 WSW 5 33 11 0 0 0 49 W 3 53 12 2 1 0 71 WNW 3 28 20 9 2 0 62 NW 4 26 24 7 3 0 64 NNW 2 20 15 1 0 0 38 Variable 0 0 0 0 0 0 0 Total 66 444 316 36 6 0 868 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 9 36 2 1 0 0 48 NNE 5 12 3 0 0 0 20 NE 10 9 2 0 0 0 21 ENE 5 17 1 0 0 0 23 E 11 22 0 0 0 0 33 ESE 7 5 3 0 0 0 15 SE 6 13 7 0 0 0 26 SSE 4 49 10 0 0 0 63 S 6 40 15 7 0 0 68 SSW 6 27 15 4 0 0 52 SW 7 30 21 1 0 0 59 WSW 15 16 3 0 0 0 34 W 11 26 5 0 0 0 42 WNW 9 17 4 1 0 0 31 NW 11 20 2 1 0 0 34 NNW 4 30 5 2 0 0 41 Variable 0 0 0 0 0 0 0 Total 126 369 98 17 0 0 610 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 3 6 1 0 0 0 10 NNE 3 5 0 1 0 0 9 NE 1 0 0 0 0 0 1 ENE 2 7 0 0 0 0 9 E 11 13 0 0 0 0 24 ESE 10 17 1 0 0 0 28 SE 7 17 1 0 0 0 25 SSE 7 57 2 0 0 0 66 S 11 44 1 0 0 0 56 SSW 15 11 0 0 0 0 26 SW 11 4 0 0 0 0 15 WSW 7 1 0 0 0 0 8 W 15 12 0 0 0 0 27 WNW 14 4 0 0 0 0 18 NW 11 8 0 0 0 0 19 NNW 5 15 1 0 0 0 21 Variable 0 0 0 0 0 0 0 Total 133 221 7 1 0 0 362 Hours of calm in this stability class: 3 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 1 0 0 0 0 0 1 NE 1 0 0 0 0 0 1 ENE 1 0 0 0 0 0 1 E 6 4 0 0 0 0 10 ESE 5 24 2 0 0 0 31 SE 7 17 3 0 0 0 27 SSE 9 20 0 0 0 0 29 S 22 23 0 0 0 0 45 SSW 18 2 0 0 0 0 20 SW 7 0 0 0 0 0 7 WSW 11 0 0 0 0 0 11 W 17 1 0 0 0 0 18 WNW 8 0 0 0 0 0 8 NW 4 2 0 0 0 0 6 NNW 5 0 0 0 0 0 5 Variable 0 0 0 0 0 0 0 Total 122 93 5 0 0 0 220 Hours of calm in this stability class: 9 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 1 0 1 S 0 0 0 2 0 0 2 SSW 0 0 1 1 0 0 2 SW 0 0 1 1 0 0 2 WSW 0 0 0 3 0 0 3 W 0 0 1 4 0 0 5 WNW 0 0 1 0 0 0 1 NW 0 0 2 5 0 0 7 NNW 0 0 0 1 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 0 6 17 1 0 24 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 1 0 0 0 1 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 1 1 0 0 0 2 SE 0 0 1 0 0 0 1 SSE 0 0 1 2 0 0 3 S 0 0 0 5 0 0 5 SSW 0 0 2 4 0 0 6 SW 0 0 1 5 0 0 6 WSW 0 0 0 2 0 0 2 W 0 0 1 2 0 0 3 WNW 0 0 0 1 2 1 4 NW 0 0 4 3 0 0 7 NNW 0 0 0 1 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 1 12 25 2 1 41 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 1 0 0 0 1 NNE 0 0 2 0 0 0 2 NE 0 1 2 0 0 0 3 ENE 0 0 1 0 0 0 1 E 0 1 0 0 0 0 1 ESE 0 1 0 0 0 0 1 SE 0 2 1 0 0 0 3 SSE 0 1 2 1 0 0 4 S 0 2 3 2 1 0 8 SSW 0 0 8 3 0 0 11 SW 0 2 8 3 0 0 13 WSW 0 0 3 2 0 0 5 W 0 1 3 3 0 0 7 WNW 0 1 1 2 0 0 4 NW 0 0 0 2 0 0 2 NNW 0 0 1 1 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 12 36 19 1 0 68 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 7 32 22 0 0 63 NNE 1 2 22 31 10 0 66 NE 1 9 12 17 2 1 42 ENE 4 5 14 17 1 0 41 E 2 21 15 2 0 0 40 ESE 4 23 13 6 0 0 46 SE 1 10 8 7 1 0 27 SSE 1 7 21 20 3 0 52 S 2 14 34 31 10 2 93 SSW 1 5 24 18 2 0 50 SW 0 20 32 17 5 0 74 WSW 1 18 17 8 2 0 46 W 0 28 30 9 2 3 72 WNW 0 12 28 15 7 2 64 NW 2 10 19 19 4 3 57 NNW 0 8 16 11 0 0 35 Variable 0 0 0 0 0 0 0 Total 22 199 337 250 49 11 868 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 3 13 12 1 0 29 NNE 1 6 16 19 1 0 43 NE 0 9 10 12 1 0 32 ENE 3 4 10 5 0 0 22 E 2 9 18 3 0 0 32 ESE 1 1 6 2 1 0 11 SE 1 3 3 7 6 1 21 SSE 2 4 8 20 3 0 37 S 0 10 11 35 11 5 72 SSW 1 1 15 28 12 5 62 SW 0 3 15 33 23 1 75 WSW 0 7 13 6 1 0 27 W 0 5 16 10 0 0 31 WNW 0 5 18 17 2 0 42 NW 3 6 19 12 0 0 40 NNW 1 10 12 10 1 0 34 Variable 0 0 0 0 0 0 0 Total 15 86 203 231 63 12 610 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 2 5 6 3 0 16 NNE 0 1 1 7 0 0 9 NE 0 4 1 5 0 0 10 ENE 2 1 3 2 0 0 8 E 1 5 10 7 2 0 25 ESE 0 0 12 11 4 0 27 SE 0 4 3 5 0 0 12 SSE 0 2 4 12 6 0 24 S 0 3 7 31 9 0 50 SSW 0 2 10 38 0 0 50 SW 1 1 8 20 1 0 31 WSW 0 4 7 13 0 0 24 W 0 5 4 6 0 0 15 WNW 0 1 18 6 0 0 25 NW 0 3 6 9 0 0 18 NNW 1 3 7 9 1 0 21 Variable 0 0 0 0 0 0 0 Total 5 41 106 187 26 0 365 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: July - September 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 3 0 1 2 0 0 6 NNE 0 2 1 0 0 0 3 NE 1 2 1 0 0 0 4 ENE 2 1 2 0 0 0 5 E 4 4 2 2 0 0 12 ESE 1 7 5 11 4 0 28 SE 0 3 4 8 9 0 24 SSE 0 3 8 9 7 1 28 S 0 4 6 5 2 0 17 SSW 0 5 7 19 1 0 32 SW 0 4 6 22 0 0 32 WSW 0 1 8 4 0 0 13 W 1 6 3 0 0 0 10 WNW 0 1 3 3 0 0 7 NW 1 0 1 2 0 0 4 NNW 0 1 2 1 0 0 4 Variable 0 0 0 0 0 0 0 Total 13 44 60 88 23 1 229 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 3

Byron Generating Station Period of Record: October - December 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 0 0 0 0 0 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 1 1 0 0 0 2 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 1 0 0 0 0 1 ESE 0 0 0 0 0 0 0 SE 0 0 1 0 0 0 1 SSE 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 2 2 0 0 0 4 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 1 0 0 0 1 NNE 0 0 0 0 0 0 0 NE 0 1 0 0 0 0 1 ENE 0 2 1 0 0 0 3 E 0 2 0 0 0 0 2 ESE 0 0 1 0 0 0 1 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 S 0 0 0 2 0 0 2 SSW 0 0 0 3 0 0 3 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 1 0 2 0 0 3 WNW 0 0 0 2 0 0 2 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 6 3 9 0 0 18 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 23 35 22 0 0 82 NNE 4 34 3 8 0 0 49 NE 0 5 2 13 0 0 20 ENE 1 9 8 0 0 0 18 E 4 19 5 1 0 0 29 ESE 1 7 4 5 0 0 17 SE 1 6 12 11 4 0 34 SSE 1 3 16 21 3 0 44 S 0 11 23 35 15 0 84 SSW 1 10 34 14 6 0 65 SW 5 18 49 5 1 0 78 WSW 7 27 31 8 5 7 85 W 3 24 39 38 15 2 121 WNW 4 28 45 30 10 0 117 NW 6 27 63 27 7 0 130 NNW 4 27 51 25 0 0 107 Variable 0 0 0 0 0 0 0 Total 44 278 420 263 66 9 1080 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 5 20 3 1 0 0 29 NNE 7 10 6 0 0 0 23 NE 2 13 3 0 0 0 18 ENE 6 21 11 0 0 0 38 E 2 10 6 0 0 0 18 ESE 1 3 8 0 0 0 12 SE 3 5 23 5 1 0 37 SSE 4 11 38 29 1 0 83 S 3 20 27 23 3 0 76 SSW 6 26 45 14 3 0 94 SW 5 38 21 7 1 0 72 WSW 12 31 30 2 1 1 77 W 10 37 17 14 4 1 83 WNW 10 31 11 12 3 0 67 NW 19 32 15 4 0 0 70 NNW 4 30 3 1 0 0 38 Variable 0 0 0 0 0 0 0 Total 99 338 267 112 17 2 835 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 1 0 0 0 1 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 2 4 1 0 0 0 7 ESE 1 6 5 0 0 0 12 SE 2 4 4 0 0 0 10 SSE 0 12 20 0 0 0 32 S 3 16 8 0 0 0 27 SSW 3 15 3 0 0 0 21 SW 6 2 0 0 0 0 8 WSW 5 3 0 0 0 0 8 W 12 15 1 0 0 0 28 WNW 10 4 0 0 0 0 14 NW 3 6 0 0 0 0 9 NNW 3 1 0 0 0 0 4 Variable 0 0 0 0 0 0 0 Total 50 88 43 0 0 0 181 Hours of calm in this stability class: 1 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 30 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 3 0 0 0 0 0 3 NNE 0 1 0 0 0 0 1 NE 1 0 0 0 0 0 1 ENE 0 0 0 0 0 0 0 E 0 0 1 0 0 0 1 ESE 2 2 1 0 0 0 5 SE 2 4 2 0 0 0 8 SSE 2 7 2 0 0 0 11 S 4 12 1 0 0 0 17 SSW 3 6 0 0 0 0 9 SW 3 0 0 0 0 0 3 WSW 0 0 0 0 0 0 0 W 3 0 0 0 0 0 3 WNW 7 1 0 0 0 0 8 NW 10 3 0 0 0 0 13 NNW 5 0 0 0 0 0 5 Variable 0 0 0 0 0 0 0 Total 45 36 7 0 0 0 88 Hours of calm in this stability class: 1 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Extremely Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 0 0 0 0 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 0 0 0 0 0 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Moderately Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 2 0 0 2 NE 0 0 0 0 0 0 0 ENE 0 0 0 0 0 0 0 E 0 0 1 0 0 0 1 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 SSE 0 0 0 1 0 0 1 S 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 1 3 0 0 4 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Slightly Unstable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 0 0 0 NNE 0 0 0 1 0 0 1 NE 0 0 0 0 0 0 0 ENE 0 1 0 1 0 0 2 E 0 0 3 0 0 0 3 ESE 0 0 0 2 0 0 2 SE 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 SSW 0 0 0 0 5 0 5 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 1 1 1 0 3 WNW 0 0 0 2 0 0 2 NW 0 0 0 0 0 0 0 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 1 4 7 6 0 18 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Neutral - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 21 18 30 12 0 82 NNE 2 15 25 11 5 1 59 NE 0 5 5 1 9 10 30 ENE 0 5 6 8 3 0 22 E 1 10 9 4 2 0 26 ESE 1 2 5 4 1 2 15 SE 0 3 3 9 8 7 30 SSE 1 3 6 11 11 12 44 S 0 5 14 14 24 23 80 SSW 2 8 17 26 13 12 78 SW 2 6 16 42 4 4 74 WSW 6 9 38 16 6 11 86 W 3 10 34 22 28 19 116 WNW 1 18 38 28 22 11 118 NW 2 17 28 58 8 7 120 NNW 1 17 32 37 13 0 100 Variable 0 0 0 0 0 0 0 Total 23 154 294 321 169 119 1080 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Slightly Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 5 21 4 1 0 32 NNE 2 2 12 8 1 0 25 NE 2 6 14 8 1 0 31 ENE 2 4 16 10 3 0 35 E 2 7 6 8 2 0 25 ESE 0 3 3 2 7 0 15 SE 0 0 3 7 14 0 24 SSE 0 2 2 12 29 17 62 S 1 2 3 14 42 18 80 SSW 0 1 11 22 38 14 86 SW 1 1 19 42 19 5 87 WSW 1 7 26 37 8 2 81 W 1 2 23 30 10 9 75 WNW 0 5 17 29 11 4 66 NW 1 7 25 20 4 1 58 NNW 2 11 33 6 1 0 53 Variable 0 0 0 0 0 0 0 Total 16 65 234 259 191 70 835 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Moderately Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 2 3 0 0 0 5 NNE 0 1 1 0 0 0 2 NE 0 1 0 0 1 0 2 ENE 0 3 0 0 0 0 3 E 0 2 1 2 0 0 5 ESE 0 0 0 1 5 0 6 SE 0 1 2 3 2 0 8 SSE 0 0 1 3 7 0 11 S 1 1 2 9 15 0 28 SSW 0 0 2 11 10 0 23 SW 0 0 1 10 2 0 13 WSW 0 0 8 9 0 0 17 W 0 0 5 12 0 0 17 WNW 0 2 8 12 0 0 22 NW 0 2 1 4 0 0 7 NNW 0 0 9 4 0 0 13 Variable 0 0 0 0 0 0 0 Total 1 15 44 80 42 0 182 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

Byron Generating Station Period of Record: October - December 2020 Stability Class - Extremely Stable - 250Ft-30Ft Delta-T (F)

Winds Measured at 250 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 5 0 0 0 5 NNE 0 5 1 1 0 0 7 NE 0 1 1 0 1 0 3 ENE 2 3 0 0 0 0 5 E 2 1 0 0 0 0 3 ESE 0 2 1 0 1 0 4 SE 0 1 1 1 2 0 5 SSE 0 0 1 3 1 0 5 S 1 1 0 3 6 0 11 SSW 0 0 0 3 3 0 6 SW 0 0 1 9 1 0 11 WSW 0 0 1 4 0 0 5 W 0 1 0 1 0 0 2 WNW 0 1 1 0 0 0 2 NW 1 2 2 0 0 0 5 NNW 0 1 6 3 0 0 10 Variable 0 0 0 0 0 0 0 Total 6 19 21 28 15 0 89 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 0 Hours of missing stability measurements in all stability classes: 0

APPENDIX G ERRATA DATA

Intentionally left blank

1. The 2019 AREOR Page B-1 referenced incorrect addresses for vegetation collection locations.

The correct locations were as follows:

Quadrant 1 - 5186 Cox Road, Stillman Valley - 4.6 miles E Quadrant 2 - 6970 Linden Wood Road, Stillman Valley - 4.9 miles SE Quadrant 3 - 555 Park Road, Oregon - 3.7 miles SW Quadrant 4 - 4615 N. Razorville Road, Byron - 2.7 SW Control - 17311 Edison Road, Rockford - 14.8 miles ENE

2. The 2019 Effluent Report (Appendix E) contained erroneous calculations for the gaseous release volume.

During the review and approval process of transitioning the Offsite Dose Calculation from RETDAS to OpenEMS program, a discrepancy was identified with calculating the gaseous release volume using pressure differential methodology. The old methodology had the volume calculated using the ratio of the delta pressure change over the starting absolute pressure, measured in percent tank volume released. This calculation does not take into account that the sample of the tank is obtained and analyzed under close to atmospheric pressure conditions and therefore the volume of the gas released must be calculated under same conditions. Using the Boyles law for an ideal gas, the newly developed formula calculates the volume of the gas under standard atmospheric pressure. It should be noted that the RETDAS program calculations have been set in accordance with the Offsite Dose Calculation Manual and the calculation methodology most likely was set during initial implementation of RETDAS effluent software. It should also be noted that at no point the dose rate to the public had exceeded a TRM or station ODCM requirements. The discrepancy equated to approximately 10% of Waste Gas Decay Tank dose increase.

APPENDIX H ANNUAL RADIOLOGICAL GROUNDWATER PROTECTION PROGRAM REPORT (ARGPPR)

Intentionally left blank NRC.Docket No: 50-454 50-455 BYRON NUCLEAR GENERATING STATION UNITS 1 and 2 Annual Radiological Groundwater Protection Program Report 1 January Through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services Byron Nuclear Generating Station Byron, IL 61010 April 2021

Intentionally left blank Table Of Contents I. Summary and Conclusions .............................................................................................. 1 II. Introduction...................................................................................................................... 3 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 C. Background Analysis ......................................................................................... 6

1. Background Concentrations of Tritium...................................................... 7 IV. Results and discussion .................................................................................................. 9 A. Groundwater Results ........................................................................................... 9 B. Drinking Water Well Survey ................................................................................. 9 C. Summary of Results - Inter-laboratory Comparison Program ............................ 9 D. Leaks, Spills, and Releases ................................................................................ 9 E. Trends.................................................................................................................. 9 F. Investigations ..................................................................................................... 10 G. Actions Taken.................................................................................................... 10

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Appendices Appendix A Location Designation Tables Table A-1 Radiological Groundwater Protection Program - Sampling Locations, Distance and Direction, Byron Nuclear Generating Station, 2020 Figures Figure A-1 Monitoring Well Locations, Byron Nuclear Generating Station, 2020 (Extra wells noted on map are for reference only.)

Appendix B Data Tables Tables Table B-I.1 Concentrations of Tritium and Strontium in Groundwater Samples Collected in the Vicinity of Byron Nuclear Generating Station, 2020

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I. Summary and Conclusions In 2006, Exelon instituted a comprehensive monitoring program to evaluate the impact of station operations on groundwater in the vicinity of Byron Nuclear Generating Station. The monitoring was conducted in two phases. Phase 1 of the monitoring was part of a comprehensive study initiated by Exelon to determine whether groundwater or surface water at and in the vicinity of Byron Nuclear Generating Station had been adversely impacted by any releases of radionuclides. Phase 1 was conducted by Conestoga Rovers and Associates (CRA) and the conclusions were made available to state and federal regulators as well as the public.

Phase 2 of the RGPP was conducted by Exelon corporate and station personnel to initiate follow up of Phase 1 and begin long-term monitoring at groundwater locations selected during Phase 1. This is the fifteenth in a series of annual reports on the status of the Radiological Groundwater Protection Program (RGPP) conducted at Byron Nuclear Generating Station. This report covers groundwater and surface water samples collected from the environment both on and off station property in 2020. During that time period, 129 analyses were performed on 62 samples from 18 locations.

In 2020, fourteen (14) Radiological Groundwater Protection Program (RGPP) monitoring wells were sampled in total. Groundwater samples were obtained in March, May, August, and November and analyzed for tritium.

Two wells contained levels of tritium above the lower limit of detection (LLD) of 200 pCi/L. They were: AR-7 (227 pCi/L in March, 289 pCi/L in June, 251 pCi/L in September, 313 pCi/L in November) and AR-11 (448 pCi/L in September, 459 pCi/L in November). Well AR-11 is near the Circulating Water Blowdown piping, where historical leakage through vacuum breakers was known to have occurred.

Tritium in Well AR-7, located on-site just west of plant structures, has been measured in this well slightly above detection limits on an intermittent basis since the well was first drilled in 2006. The tritium present in this well is likely due to legacy tritium prior to 2006 or precipitation recapture and is not believed to be the result of new leaks. The tritium measured in this well has been at or below tritium levels that have been historically measured in rainwater as a result of precipitation recapture from permitted gaseous releases. In August 2014, a break in the well piping was discovered about six feet below the surface that could have served as the entry point for tritium in the recapture water. Tritium present in well AR-7 has shown a gradual decrease since 2014. Should the water in these aquifers migrate to off-site wells used for drinking, the off-site dose consequence from tritium present in any of these three wells would be negligible.

There are no existing or new leaks evident at the site and all groundwater well sample results are well below the drinking water tritium standard of 20,000 pCi/L.

In December 2018, two new wells, AR-12 and AR-13, were installed near well AR-7. These wells were added to provide additional monitoring capabilities in the area directly west of plant structures. No tritium was detected in these wells during 2020.

Strontium-89 (Sr-89) and Strontium-90 (Sr-90) were not detected in any samples above their respective LLDs of 10 and 1 pCi/L.

In assessing all the data gathered for this report, it was concluded that the operation of Byron Nuclear Generating Station had no adverse radiological impact on the environment, and there are no known active releases into the groundwater at Byron Nuclear Generating Station.

II. Introduction The Byron Station, a two-unit PWR station, is located about two miles east of the Rock River and approximately three miles southwest of Byron in Ogle County, Illinois. The reactors are designed to have capacities of 1,268 and 1,241 MW gross, respectively. Unit One loaded fuel in November 1984 and went online February 2, 1985. Unit Two went online January 9, 1987.

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

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

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

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

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

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

5. Regularly assess analytical results to identify adverse trends

6. Take necessary corrective actions to protect groundwater resources B. Implementation of the Objectives The objectives identified have been implemented at Byron Nuclear Generating Station as discussed below:

1. Exelon and its consultant identified locations as described in the Phase 1 study. Phase 1 studies were conducted by Conestoga Rovers and Associates (CRA) and the results and conclusions were made available to state and federal regulators as well as the public.

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

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

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

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

C. Program Description Sample Collection Sample locations can be found in Table A-1 and Figure A-1, Appendix A.

Groundwater/Surface Water Samples of water are collected, managed, transported and analyzed in accordance with approved procedures following EPA methods.

Groundwater is collected from drilled wells. Surface water is collected from the Construction Runoff Pond (CROP), which collects stormwater runoff from the site protected area prior to discharge offsite. 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. 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." The chemical properties of tritium are essentially those of ordinary hydrogen.

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

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

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

III. Program Description A. Sample Analysis This section describes the general analytical methodologies used by TBE to analyze the environmental samples for radioactivity for the Byron Nuclear Generating Station RGPP in 2020.

In order to achieve the stated objectives, the current program includes the following analyses (as required by procedure):

1. Concentrations of strontium in groundwater

2. Concentrations of tritium in groundwater/surface water No gamma nuclide or gross alpha monitoring was performed in 2020.

B. Data Interpretation The radiological data collected prior to Byron Nuclear Generating Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, Byron Nuclear Generating Station was considered operational at initial criticality.

Several factors were important in the interpretation of the data:

1. Lower Limit of Detection and Minimum Detectable Concentration The lower limit of detection (LLD) is 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) as well as all sources of error (Total Propagated Uncertainty or TPU).

Each result has two values calculated. Exelon reports the TPU by following the result with plus or minus +/- the estimated sample standard deviation, as TPU, that is obtained by propagating all sources of analytical uncertainty in measurements.

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

C. Background Analysis A pre-operational radiological environmental monitoring program (pre-operational REMP) was conducted to establish background radioactivity levels prior to operation of the Station. The environmental media sampled and analyzed during the pre-operational REMP were atmospheric radiation, fall-out, domestic water, surface water, marine life, and foodstuffs. The results of the monitoring were detailed in the report entitled, Environmental Radiological Monitoring for Byron Nuclear Generating Nuclear Power Station, Commonwealth Edison Company, Annual Report 1984, April, 1985.

The pre-operational REMP contained analytical results from samples collected from the surface water and groundwater. All groundwater samples listed in the pre-Operational REMP report were <200 pCi/L.

1. Background Concentrations of Tritium The purpose of the following discussion is to summarize background measurements of tritium in various media performed by others.

Additional detail may be found by consulting references (CRA 2006).

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

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

A major anthropogenic source of tritium and Sr-90 comes from the former atmospheric testing of thermonuclear weapons.

Levels of tritium in precipitation increased significantly during the 1950s and early 1960s, and later with additional testing, resulting in the release of significant amounts of tritium to the atmosphere.

The Canadian heavy water nuclear power reactors, other commercial power reactors, nuclear research and weapons production continue to influence tritium concentrations in the environment.

b. Precipitation Data Precipitation samples are routinely collected at stations around the world for the analysis of tritium and other radionuclides. Two publicly available databases that provide tritium concentrations in precipitation are Global Network of Isotopes in Precipitation (GNIP) and USEPAs RadNet database. GNIP provides tritium precipitation concentration data for samples collected worldwide from 1960 to 2006. RadNet provides tritium precipitation concentration data for samples collected at stations throughout the U.S. from 1960 up to and including 2006. Based on GNIP data for sample stations located in the U.S. Midwest, tritium concentrations peaked around 1963. This peak, which approached 10,000 pCi/L for some stations, coincided with the atmospheric testing of thermonuclear weapons. Tritium concentrations in surface water showed a sharp decline up until 1975 followed by a gradual decline since that time. Tritium concentrations in Midwest precipitation have typically been below 100 pCi/L since around 1980. Tritium concentrations in wells may still be above the 200 pCi/L detection limit from the external causes described above. Water from previous years and decades is naturally captured in groundwater, so some well water sources today are affected by the surface water from the 1960s that was elevated in tritium.

c. Surface Water Data Tritium concentrations are routinely measured in large surface water bodies, including Lake Michigan and the Mississippi River.

Illinois surface water data were typically less than 100 pCi/L.

The USEPA RadNet surface water data typically has a reported Combined Standard Uncertainty of 35 to 50 pCi/L. According to USEPA, this corresponds to a +/- 70 to 100 pCi/L 95% confidence bound on each given measurement. Therefore, the typical background data provided may be subject to measurement uncertainty of approximately +/- 70 to 100 pCi/L.

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

IV. Results and Discussion A. Groundwater Results Groundwater Samples were collected from on- and off-site wells throughout the year in accordance with the station radiological groundwater protection program.

Analytical results and anomalies are discussed below:

Tritium Samples from all locations were analyzed for tritium activity (Table B-I.1, Appendix B). Tritium values ranged from less than the detection limit to 459 pCi/L. Outside of the station boundary, tritium concentrations were all less than detection limit (<200 pCi/L). The tritium detected in groundwater samples has been isolated to the Galena- Platteville aquifer, which is isolated from the deeper regional groundwater aquifer by the semi-confining Glenwood Formation. Groundwater quality data from production wells and monitoring wells at the station located below this aquifer do not indicate concentrations of tritium greater than the LLD of 200 pCi/L. As such, the tritium impact is limited to the Galena- Platteville aquifer.

Strontium Strontium-89 (Sr-89) and Strontium-90 (Sr-90) were not detected in any samples above their respective LLDs of 10 and 1 pCi/L.

B. Drinking Water Well Survey No drinking water well surveys were conducted in 2020.

C. Summary of Results - Inter-Laboratory Comparison Program Inter-Laboratory Comparison Program results for TBE are presented in the AREOR.

D. Leaks, Spills, and Releases There are no new previously unidentified leaks or plumes at Byron Station.

There were no new leaks, spills or releases at Byron Station in 2020.

E. Trends Wells AR-4 and AR-11 have shown an overall decrease in tritium concentration since first sampled in 2006. Tritium has been measured in Well AR-7 since 2012, however, tritium has been previously measured in this well and it is believed to be the result of legacy tritium prior to 2006 or precipitation recapture, not the result of a new spill or leak.

F. Investigations There were no investigations that took place in 2020 as a result of groundwater sample results.

G. Actions Taken

1. Compensatory Actions No compensatory actions were initiated in 2020.

2. Installation of Monitoring Wells No new monitoring wells were installed in 2020.

3. Actions to Recover/Reverse Plumes No actions were undertaken to recover/reverse plumes in 2020.

APPENDIX A LOCATION DESIGNATION

Intentionally Left Blank TABLE A-1: Radiological Groundwater Protection Program - Sampling Locations Distance and Direction, Byron Nuclear Generating Station, 2020 Site Site Type Temporary/Permanent Distance and Direction AR-1 Monitoring Well Permanent 0.36 miles/NNW AR-2 Monitoring Well Permanent 0.6 miles/NW AR-3 Monitoring Well Permanent 0.8 miles/NW AR-4 Monitoring Well Permanent 1.36 miles/WNW AR-5 Monitoring Well Permanent 1.92 miles/WNW AR-6 Monitoring Well Permanent 2.04 miles/WNW AR-7 Monitoring Well Permanent 0.04 miles/W AR-8 Monitoring Well Permanent 0.12 miles/S AR-9 Monitoring Well Permanent 0.24 miles/E AR-10 Monitoring Well Permanent 0.28 miles/NE AR-11 Monitoring Well Permanent 1.36 miles/WNW AR-12 Monitoring Well Permanent 366 feet/W AR-13 Monitoring Well Permanent 461 feet/WSW CAR-1 Monitoring Well Permanent 2.25 miles/WNW CAR-3 Monitoring Well Permanent 0.16 miles/SE TW-13 Monitoring Well Permanent 2.3 miles/WNW CROP Surface Water Permanent 0.2 miles NE A-1

A-2 Figure A-1 Monitoring Well Locations, Byron Nuclear Generating Station, 2020

APPENDIX B DATA TABLES

Intentionally Left Blank TABLE B-I.1 CONCENTRATIONS OF TRITIUM AND STRONTIUM IN GROUNDWATER SAMPLES COLLECTED IN THE VICINITY OF BYRON NUCLEAR GENERATING STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 Sr-89 Sr-90 AR-1 03/18/20 < 188 AR-1 09/02/20 < 179 < 7.3 < 0.7 AR-1 11/03/20 < 190 AR-2 09/02/20 < 179 AR-3 03/18/20 < 185 AR-3 09/02/20 < 182 < 6.8 < 0.8 AR-3 11/04/20 < 191 AR-4 03/18/20 197 +/- 116 AR-4 09/02/20 < 185 < 4.0 < 0.9 AR-4 11/04/20 < 190 AR-7 03/17/20 227 +/- 122 AR-7 06/03/20 289 +/- 124 AR-7 09/03/20 251 +/- 120 < 7.5 < 0.8 AR-7 11/02/20 313 +/- 137 AR-8 03/17/20 < 184 AR-8 09/03/20 < 184 < 6.8 < 0.7 AR-8 11/02/20 < 183 AR-9 03/17/20 < 183 AR-9 09/04/20 < 178 < 6.9 < 0.9 AR-9 11/03/20 < 179 AR-10 09/02/20 < 185 AR-11 09/02/20 448 +/- 132 AR-11 11/04/20 459 +/- 137 AR-12 03/17/20 < 189 AR-12 06/09/20 < 179 AR-12 09/03/20 < 186 < 7.1 < 0.6 AR-12 11/02/20 < 176 AR-13 03/17/20 < 183 AR-13 09/03/20 < 179 < 7.9 < 0.7 AR-13 11/03/20 < 182 CAR-1 09/02/20 < 183 CAR-3 03/17/20 < 186 CAR-3 09/03/20 < 179 < 6.9 < 0.9 CAR-3 11/03/20 < 180 TW-13 09/02/20 < 181

CROP 03/17/20 < 182

CROP 09/03/20 < 190 < 7.7 < 0.9

CROP 11/03/20 < 178

Surface Water Sample B-1

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