RA21-031, 2020 Annual Radiological Environmental Operating Report

2020 Annual Radiological Environmental Operating Report

ML21133A268
Person / Time
Site:	LaSalle
Issue date:	05/13/2021
From:	Washko J Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA21-031
Download: ML21133A268 (177)

Text

LaSalle County Station Exelon Generation 2601 North 21 st Road Marseilles, IL 61341 815-415-2000 Telephone www.exeloncorp.com RA21-031 10 CFR 50 Appendix I May 13, 2021 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374

Subject:

2020 Annual Radiological Environmental Operating Report Enclosed is the Exelon Generation Company, LLC, 2020 Annual Radiological Environmental Operating Report for LaSalle County Station, submitted in accordance with Technical Specifications 5.6.2, "Annual Radiological Environmental Operating Report." The enclosed report contains the results of groundwater monitoring conducted in accordance with Exelon's Radiological Groundwater Protection Program, which is a voluntary program implemented in 2006. This information is being reported in accordance with a nuclear industry initiative.

There are no regulatory commitments in this letter. Should you have any questions concerning this report, please contact Mr. Daniel Mearhoff, Regulatory Assurance Manager, at (815) 415-2800.

Respectfully,

.,:)~

Jo ko Sit sident LaSalle County Station

Enclosure:

LaSalle County Station Units 1 and 2 Annual Radiological Environmental Operating Report 1 January through 31 December 2020 cc: Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - LaSalle County Station

Docket No: 50-373 50-374 LASALLE COUNTY STATION UNITS 1 and 2 Annual Radiological Environmental Operating Report 1 January through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services LaSalle County Station Marseilles, IL 61341 May 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/Well 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. Food Products.............................................................................. 12

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

Appendices Appendix A Radiological Environmental Monitoring Report Annual Summary Tables Table A-1 Radiological Environmental Monitoring Program Annual Summary for the LaSalle County 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, LaSalle County Station, 2020 Table B-2 Radiological Environmental Monitoring Program - Summary of Sample Collection and Analytical Methods, LaSalle County Station, 2020 Figures Figure B-1 Inner Ring OSLD Locations of the LaSalle County Station, 2020 Figure B-2 Outer Ring OSLD Locations and Fixed Air Sampling Locations of the LaSalle County Station, 2020 Figure B-3 Ingestion and Waterborne Exposure Pathway Sample Locations of the LaSalle County Station, 2020 Appendix C Data Tables and Figures - Primary Laboratory Tables Table C-I.1 Concentrations of Gross Beta in Surface Water Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-I.2 Concentrations of Tritium in Surface Water Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-I.3 Concentrations of Gamma Emitters in Surface Water Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-II.1 Concentrations of Tritium in Ground/Well Water Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-II.2 Concentrations of Gamma Emitters in Ground/Well Water Samples Collected in the Vicinity of LaSalle County Station, 2020 ii

Table C-III.1 Concentrations of Gamma Emitters in Fish Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-IV.1 Concentrations of Gamma Emitters in Sediment Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-V.1 Concentrations of Gross Beta in Air Particulate Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-V.2 Monthly and Yearly Mean Values of Gross Beta Concentrations in Air Particulate Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-V.3 Concentrations of Gamma Emitters in Air Particulate Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-VI.1 Concentrations of I-131 in Air Iodine Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-VII.1 Concentrations of I-131 in Milk Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-VII.2 Concentrations of Gamma Emitters in Milk Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-VIII.1 Concentrations of Gamma Emitters in Food Product Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-VIII.2 Concentrations of Gamma Emitters in Vegetation Samples Collected in the Vicinity of LaSalle County Station, 2020 Table C-IX.1 Quarterly DLR Results for LaSalle County Station, 2020 Figures Figure C-1 Surface Water - Gross Beta - Stations L-21 (C) and L-40 Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-2 Surface Water - Tritium - Stations L-21 (C) and L-40 Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-3 Air Particulate - Gross Beta - Stations L-01 and L-03 Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-4 Air Particulate - Gross Beta - Stations L-05 and L-06 Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-5 Air Particulate - Gross Beta - Station L-10 (C) Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-6 Air Particulate - Gross Beta - Stations L-04 and L-07 Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-7 Air Particulate - Gross Beta - Stations L-08 and L-11 Collected in the Vicinity of LSCS, 2005 - 2020 Figure C-8 Air Particulate - Gross Beta - Station L-11A Collected in the Vicinity of LSCS, 2016 - 2020 iii

Appendix D Inter-Laboratory Comparison Program Tables Table D-1 Analytics Environmental Radioactivity Cross Check Program Teledyne Brown Engineering Environmental Services, 2020 Table D-2 DOEs Mixed Analyte Performance Evaluation Program (MAPEP)

Teledyne Brown Engineering Environmental Services, 2020 Table D-3 ERA Environmental Radioactivity Cross Check Program Teledyne Brown Engineering Environmental Services, 2020 Appendix E Effluent Data 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 LaSalle County Station (LSCS) by Exelon covers the period 1 January 2020 through 31 December 2020. During that time period, 1,325 analyses were performed on 1,226 samples. In assessing all the data gathered for this report and comparing these results with preoperational data, it was concluded that the operation of LSCS had no adverse radiological impact on the environment.

Surface water samples were analyzed for concentrations of gross beta, tritium and gamma-emitting nuclides. Ground/well water samples were analyzed for concentrations of tritium and gamma-emitting nuclides. No fission or activation products were detected. Gross beta and tritium activities detected were consistent with those detected in previous years.

Commercially and recreationally important fish species were sampled and analyzed for concentrations of gamma-emitting nuclides. No fission or activation products were detected in fish.

Sediment samples were analyzed for concentrations of 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 activity 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.

Concentrations of naturally-occurring potassium-40 (K-40) were consistent with those detected in previous years. No fission or activation products were found.

All nuclides were below the minimum detectable activity.

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

Vegetation 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) for the Radiological Environmental Monitoring Program (REMP). The results from the environmental gamma radiation monitoring program were consistent with those detected in previous years.

II. Introduction The LaSalle County Station (LSCS), consists of two boiling water reactors, each rated for 3,546 MWt. Both units are owned and operated by Exelon Corporation and are located in LaSalle County, Illinois. Unit 1 went critical on 16 March 1982.

Unit 2 went critical on 02 December 1983. The site is located in northern Illinois, approximately 75 miles southwest of Chicago, Illinois.

A Radiological Environmental Monitoring Program (REMP) for LSCS was initiated in 1982 (the preoperational period for most media covers the periods 1 January 1979 through 26 December 1981 and was summarized in a separate report.).

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 LSCS REMP were collected for Exelon Nuclear by Environmental Inc. (Midwest Labs). This section describes the general collection methods used by Environmental Inc. (Midwest Labs) to obtain environmental samples for the LSCS REMP in 2020. Sample locations and descriptions can be found in Tables B-1 and B-2, and Figures B-1 through B-3, Appendix B.

Aquatic Environment The aquatic environment was evaluated by performing radiological analyses on samples of surface water, ground/well water, fish, and sediment. Two gallon water samples were collected weekly from two surface water locations (L-21 and L-40) and composited for monthly and quarterly required analyses. Control location was L-21. Two ground/well water locations (L-27 and L-28) were also grab sampled quarterly. All samples were collected via grab sample. The samples were then transferred to new unused plastic containers. Both the grab container and the sample containers were rinsed with source water prior to actual sample collection. Fish samples were collected semiannually at three locations, L-34, L-35 and L-36 (Control). Sediment samples composed of recently deposited substrate were collected at three locations semiannually, L-21 (Control), L-40 and L-41.

Atmospheric Environment The atmospheric environment was evaluated by performing radiological analyses on samples of airborne particulate and iodine. Airborne particulate and iodine samples were collected and analyzed weekly at nine locations (L-01, L-03, L-04, L-05, L-06, L-07, L-08, L-10, and L-11A). The control location was L-10. Airborne particulate and iodine samples were obtained at each location, using a vacuum pump to pull air through a glass fiber particulate filter and iodine cartridge. The pumps were run continuously and sampled air at the rate of approximately one cubic foot per minute. The particulate filters and iodine cartridges were replaced weekly and sent to the laboratory for analysis.

Terrestrial Environment The terrestrial environment was evaluated by performing radiological analyses on samples of milk and food product. Samples are typically collected biweekly at one milk location (L-42) from May through September, and monthly from December through April. The control location was L-42.

All samples, when available, 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 during the growing season at five locations (L-Quad Control, L-Quad 1, L-Quad 2, L-Quad 3 and L-Quad 4). The control location was L-Quad Control. Various types of samples were collected and placed in new unused plastic bags and sent to the laboratory for analysis.

Vegetation samples were collected monthly during the growing season from May through October at three locations (L-Veg C, L-ESE1, and L-ESE2).

The control location was L-Veg C and was located in the lowest deposition sector (ENE sector) surrounding LaSalle. Various vegetation samples were also collected in the highest deposition sector (ESE sector) surrounding LaSalle. The samples were collected and placed in new unused plastic bags and sent to the laboratory for analysis.

Ambient Gamma Radiation Beginning in the first quarter of 2012, Exelon changed the type of dosimetry used for the Radiological Environmental Monitoring Program (REMP).

Optically Stimulated Luminescent Dosimetry (OSLD) were deployed and Thermo-luminescent Dosimetry (TLD) were discontinued. This change may cause step changes in readings, up or down, depending on site characteristics. However, 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).

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

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

An outer ring consisting of 17 locations (L-201, L-202, L-203, L-204, L-205A, L-205B, L-206, L-207, L-208, L-209, L-210, L-211, L-212, L-213, L-214, L-215 and L-216) extending to approximately 5 miles from the site designed to measure possible exposures to nearby population.

An other set consisting of eight locations (L-01, L-03, L-04, L-05, L-06, L-07, L-08, and L-11A).

The balance of one location (L-10) 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 LSCS, if any, would be most significant;

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

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

(Two OSLDs were placed at each location approximately six feet above ground level.)

B. Sample Analysis This section describes the general analytical methodologies used by Environmental Inc. (Midwest Labs) and TBE to collect and analyze, respectively, the environmental samples for radioactivity for the LSCS 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/well and surface water, air particulates, milk, fish, sediment and vegetation

3. Concentrations of tritium in ground/well and surface water

4. Concentrations of I-131 in air and milk

5. Ambient gamma radiation levels at various site environs C. Data Interpretation The radiological and direct radiation data collected prior to LaSalle County Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, LaSalle County 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) is defined as the smallest concentration of radioactive material in a sample that would yield a net count (above background) that would be detected with only a 5%

probability of falsely concluding that a blank observation represents a "real" signal. The LLD is intended as a before the fact (a priori) estimate of a system (including instrumentation, procedure and sample type) and not as an after the fact (a posteriori) criteria for the presence of activity. All analyses were designed to achieve the required LSCS 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, food products, and vegetation: 12 nuclides including Mn-54, Co-58, Fe-59, Co-60, Zn-65, Zr-95, Nb-95, I-131, Cs-134, Cs-137, Ba-140, and La-140 were reported.

For ground/well water, fish, sediment, air particulate and milk:

11 nuclides including Mn-54, Co-58, Fe-59, Co-60, Zn-65, Zr-95, Nb-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 LSCS REMP had a sample recovery rate of 98.1%. Sample anomalies and missed samples are listed in the following tables:

Table D-1 LISTING OF SAMPLE ANOMALIES Sample Location Collection Reason Type Code Date Lower reading of 155.0 hrs, possibly due to a power outage. NOTE:

AP/AI L-05 01/23/20 during the collection on 01/30/20, the timer indicated 167.8 hrs; normal reading for the 7 days collection period.

Timer indicates approximately 8 hrs less than expected for the 7 days collection period. Possible power outage. NOTE: during the collection AP/AI L-05 02/20/20 on 02/27/20, the timer indicated 168.1 hrs; normal reading for the 7 days collection period.

Low reading of 85.5 hrs during a 7 days collection period, possibly due AP/AI L-07 05/28/20 to a power outage. NOTE: later determined the cause as a timer failure.

Table D-1 LISTING OF SAMPLE ANOMALIES (contd)

Sample Location Collection Reason Type Code Date Low reading of 78.3 hrs during a 6 days collection period. Cause determined to be a faulty timer. Unable to exchange the timer in field; AP/AI L-07 06/03/20 pump replaced. Running time determined based on the installation/

collection times to be 144.1 hrs.

Low reading of 68.6 hrs due to a fuse failure. Fuse replaced, pump back to normal operation. NOTE: during the 07/29/20 collection, the AP/AI L-08 07/23/20 timer indicated 144.9 hrs; normal reading for the 6 days collection period.

Timer indicates approximately 9.2 hrs less than expected for the AP/AI L-01 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 9.2 hrs less than expected for the AP/AI L-05 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 7.1 hrs less than expected for the AP/AI L-05 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 8.8 hrs less than expected for the AP/AI L-06 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 27 hrs less than expected for the AP/AI L-07 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 4 hrs less than expected for the AP/AI L-08 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 20 hrs less than expected for the AP/AI L-10 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

Timer indicates approximately 9 hrs less than expected for the AP/AI L-11A 08/13/20 collection period due to a power outage caused by severe winds and storms in the area.

L-03-1 08/13/20 Unable to check the OSLD samples; access road blocked by downed OSLD L-03-2 08/20/20 power lines.

Sample collected after 3 weeks run, after the access road reopened.

AP/AI L-03 08/27/20 Station informed; samples decided to be valid for testing.

Sample collected one day later than the whole batch due to AP/AI L-03 09/03/20 inaccessibility of the location.

Timer indicates approximately 20 hrs less than expected for the collection period possibly due to a power outage. NOTE: during the AP/AI L-11A 0902/20 09/10/20 collection, the timer indicated 168.9 hrs; normal reading for the 8 days collection period.

AP/AI L-11A 10/22/20 Pump found not running; timer indicated 131.9 hrs. Pump exchanged.

Unable to read the run time due to the timers failure; filter consistent AP/AI L-11A 12/23/20 with the estimated running time. Timer exchanged.

Table D-2 LISTING OF MISSED SAMPLES Sample Location Collection Reason Type Code Date SW L-40 03/19/20 No sample; location closed due to a national health emergency.

Pump found not running, with cord partially disconnected. Timer indicated 25 hrs. The cord and socket refastened and sealed with tape, AP/AI L-03 04/16/20 pump reset and observed working well. Filter appears very light.

Station informed; samples discarded.

L-21 Original sample lost in transit on 05/04/20. Sample recomposited and SW April, 2020 L-40 sent on 07/08/20. Unable to reach required LLD.

08/13/20 Station inaccessible due to the road being blocked by a downed power AP/AI L-03 08/20/20 line. Samples not collected.

Sample found on the ground. One OSLD missing; premises searched OSLD L-209-1 09/30/20 unsuccessfully.

Unable to collect milk; farmer stopped milking cows before calving MI L-42 12/30/20 season.

AP/AI L-01 12/30/20 No power at the station due to a downed wire. Station notified.

Each program exception has been reviewed to understand the causes of the program exception. 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 (L-21 and L-40). Of these locations only L-40 located downstream, could be affected by LaSalles effluent releases. The following analyses were performed:

Gross Beta Samples from all locations were analyzed for concentrations of gross beta (Table C-I.1, Appendix C). Gross beta was detected in 24 out of 24 samples with a range of 3.0 to 10.7 pCi/L. Concentrations detected were consistent with those detected in previous years (Figure C-1, Appendix C). The required LLD was met for all samples.

Tritium Quarterly composites of weekly collections were analyzed for tritium activity (Table C-I.2, Appendix C). Tritium was detected in 1 of 8 samples with a concentration of 257 pCi/L. Concentrations detected were consistent with those detected in previous years (Figure C-2, Appendix C).

Gamma Spectrometry Samples from both locations were analyzed for gamma-emitting nuclides (Table C-I.3, Appendix C). No nuclides were detected, and all required LLDs were met.

2. Ground/Well Water Quarterly grab samples were collected at two locations (L-27 and L-28). Wells 4, 5 and 6 are associated with L-28. L-27 and L-28 Well 6 could be affected by LaSalles 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 contractually-required 200 pCi/L LLDs were met.

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 were collected at three locations (L-34, L-35 and L-36) semiannually. Locations L-34 and L-35 could be affected by LaSalles effluent releases. The following analysis was performed:

Gamma Spectrometry The edible portion of fish samples from both locations was analyzed for gamma-emitting nuclides (Table C-III.1, Appendix C). Naturally-occurring K-40 was found at all stations and ranged from 2,607 to 3,568 pCi/kg wet. No fission or activation products were found.

4. Sediment Aquatic sediment samples were collected at three locations (L-21, L-40 and L-41) semiannually. Location L-21 is located upstream and is not affected by LaSalles liquid effluent releases. Locations L-40 and L-41, located downstream, could be affected by LaSalles effluent releases.

The following analysis was performed:

Gamma Spectrometry Sediment samples from the three locations were analyzed for gamma-emitting nuclides (Table C-IV.1, Appendix C). Naturally- occurring Be-7 was found at two stations with concentrations ranging from 1,172 to 3,268 pCi/L. Naturally- occurring K-40 was found at all stations and ranged from 5,569 to 19,170 pCi/kg dry. No fission or activation products were found.

B. Atmospheric Environment

1. Airborne

a. Air Particulates Continuous air particulate samples were collected from nine locations on a weekly basis. The nine locations were separated into four groups: Group I (onsite) represents locations within the LSCS site boundary (L-03 and L-05), Group II (near-site) represents the locations near the LSCS site (L-01 and L-06),

Group III (far-field) represents the locations at an intermediate distance from LSCS (L-04, L-07, L-08, and L-11A) and Group IV (control) represents the control location at a remote distance (L-10). 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 four groups aid in determining the effects, if any, resulting from the operation of LSCS. The results from the onsite locations (Group I) ranged from 6 to 31E-3 pCi/m3 with a mean of 16E-3 pCi/m3. The results from the near-site location (Group II) ranged from 6 to 32E-3 pCi/m3 with a mean of 16E-3 pCi/m3.

The results from the far-field locations (Group III) ranged from 6 to 35E-3 pCi/m3 with a mean of 17E-3 pCi/m3. The results from the control location (Group IV) ranged from 9 to 36E-3 pCi/m3 with a mean of 17E-3 pCi/m3. Comparison of the 2020 air particulate data with previous years data indicate no effects from the operation of LSCS (Figures C-3 through C-8, Appendix C). In addition, comparisons of the weekly mean values for 2020 indicate no notable differences among the four groups.

Gamma Spectrometry Weekly samples were composited quarterly and analyzed for gamma-emitting nuclides (Table C-V.3, Appendix C). Naturally-occurring Be-7, due to cosmic ray activity, was detected in 36 of 36 samples. These values ranged from 57 to 171 E-3 pCi/m3. All other nuclides were less than the MDC.

b. Airborne Iodine Continuous air samples were collected from ten locations (L-01, L-03, L-04, L-05, L-06, L-07, L-08, L-10, and L-11A) and analyzed weekly for I-131 (Table C-VI.1, Appendix C). No I-131 was detected.

2. Terrestrial

a. Milk Samples were collected from one location (L-42) biweekly May through October and monthly December through April. The following analyses were performed:

Iodine-131 Milk samples from the location were analyzed for concentrations of I-131 (Table C-VII.1, Appendix C). I-131 was not detected, and the required LLDs were met.

Gamma Spectrometry Milk samples were analyzed for concentrations of gamma-emitting nuclides (Table C-VII.2, Appendix C). Naturally-occurring K-40 activity was found in all milk samples and ranged from 800 to 1,319 pCi/l. No other nuclides were detected, and all required LLDs were met.

b. Food Products Food product samples were collected at four locations (L-Quad 1, L-Quad 2, L-Quad 3 and L-Quad 4) when available. All locations could be affected by LaSalles effluent releases. The following analysis was performed:

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

c. Vegetation Vegetation samples were collected monthly during the growing season from May through October at three locations (L-Veg C, L-ESE-1, and L-ESE-2). The control location was L-Veg C and was located in the lowest deposition sector (ENE sector) surrounding LaSalle. Various vegetation samples were also collected in the highest deposition sector (ESE sector) surrounding LaSalle. The following analyses were performed:

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

C. Ambient Gamma Radiation Ambient gamma radiation levels were measured utilizing Optically Stimulated Luminescence Dosimeters (OSLD). Forty-two OSLD locations were established around the site. Results of OSLD measurements are listed in Tables C-IX.1, Appendix C.

All OSLD measurements were at or below 24 mrem/quarter, with a range of 5.9 to 23.5 mrem/quarter. A comparison of the Normalized Annual Dose to the Baseline Background and Minimum Differential Dose indicates that there is no evidence of dose which could be attributed to facility-related direct radiation.

D. Land Use Census A Land Use Census conducted August 26, 2020, around the LaSalle County Station (LSCS) was performed by Environmental Inc. (Midwest Labs) for Exelon Nuclear to comply with Radiological Effluent Control 12.5.2 of the LaSalles Offsite Dose Calculation Manual. The purpose of the survey was to document the nearest resident and milk producing animal in each of the sixteen 22 1/2 degree sectors around the site within 10 km (6.2 miles). The distance and direction of all locations from the LSCS reactor buildings were positioned using Global Positioning System (GPS) technology. Since there were no milk animals within 10 km of LSCS, beef cows were identified. There were no changes required to the LSCS REMP as a result of this survey. The results of this survey are summarized below:

Distance in Miles from the LSCS Reactor Buildings Sector Residence Livestock Milk Farm Miles Miles Miles A N 3.9 4.0 -

B NNE 1.6 1.7 -

C NE 2.1 3.5 -

D ENE 3.3 4.6 -

E E 3.2 - 14.2 F ESE 1.4 - -

G SE 1.7 5.1 -

H SSE 1.8 4.7 -

J S 1.5 1.5 -

K SSW 0.7 - -

L SW 1.0 5.8 -

M WSW 1.5 - -

N W 1.7 3.0 -

P WNW 0.9 3.0 -

Q NW 1.7 3.3 -

R NNW 1.7 4.5 -

E. Errata Data There is no errata data for 2020.

F. Summary of Results - Inter-Laboratory Comparison Program The TBE Laboratory analyzed Performance Evaluation (PE) samples of air particulate, air iodine, milk, soil, vegetation, and water matrices for various analytes. The PE samples supplied by Analytics Inc., Environmental Resource Associates (ERA) and Department of Energy (DOE) Mixed Analyte Performance Evaluation Program (MAPEP), were evaluated against the following pre-set acceptance criteria:

1. Analytics Evaluation Criteria Analytics evaluation report provides a ratio of TBEs result and Analytics known value. Since flag values are not assigned by Analytics, TBE evaluates the reported ratios based on internal QC requirements 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, National Environmental Laboratory Accreditation Conference (NELAC), state-specific Performance Testing (PT) program requirements or ERAs SOP for the Generation of Performance Acceptance Limits, as applicable.

The acceptance limits are either determined by a regression equation specific to each analyte or a fixed percentage limit promulgated under the appropriate regulatory document.

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. Seven analyses did not meet the specified acceptance criteria for the following reasons and were addressed through the TBE Corrective Action Program. A summary is found below:

1. The MAPEP February 2020 AP U-233/234 and U-238 results were evaluated as Not Acceptable. The reported value for U-233/234 was 0.0416 +/- 0.0102 Bq/sample and the known result was 0.075 Bq/sample (acceptance range 0.053 - 0.098). The reported value for U-238 was 0.0388 +/- 0.00991 Bq/sample and the known result was 0.078 Bq/sample (acceptance range 0.055 - 0.101). This sample was run as the workgroup duplicate and had RPDs of 10.4% (U-234) and 11.7% (U-238). After the known results were obtained, the sample was relogged. The filter was completely digested with tracer added originally; the R1 results were almost identical. It was concluded that the recorded tracer amount was actually double, causing the results to be skewed. Lab worksheets have been modified to verify actual tracer amount vs. LIMS data. TBE changed vendors for this cross-check to ERA MRAD during the 2nd half of 2020. Results were acceptable at 97.8% for U-234 and 106% for U-238. (NCR 20-13)

2. The Analytics September 2020 milk Sr-89 result was evaluated as Not Acceptable. The reported value was 62.8 pCi/L and the known result was 95.4 (66%). All QC data was reviewed and there were no anomalies. This was the first failure for milk Sr-89 since 2013 and there have only been 3 upper/lower boundary warnings since that time. It is believed that there may have been some Sr-89 loss during sample prep. The December 2020 result was at 92% of the known.

(NCR 20-19)

3. The ERA October 2020 water I-131 result was evaluated as Not Acceptable. The reported value was 22.9 pCi/L and the known result was 28.2 (acceptance range 23.5 - 33.1). The reported result was 81% of the known, which passes TBE QC criteria. This was the first failure for water I-131. (NCR 20-17)

4. The ERA October 2020 water Gross Alpha and Gross Beta results were evaluated as Not Acceptable. The reported/acceptable values and ranges are as follows:

Reported Known Range Gross Alpha 40.0 26.2 13.3 - 34.7 Gross Beta 47.5 69.1 48.0 - 76.0 All QC data was reviewed with no anomalies and a cause for failure could not be determined. This was the first failure for water Gross Beta. A Quick Response follow-up cross-check was analyzed as soon as possible with acceptable results at 96.8% for Gross Alpha and 102% for Gross Beta. (NCR 20-18)

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

(NCR 20-20)

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

Intentionally left blank APPENDIX A RADIOLOGICAL ENVIRONMENTAL MONITORING REPORT ANNUAL

SUMMARY

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

SUMMARY

FOR THE LASALLE COUNTY STATION, 2020 NAME OF FACILITY: LASALLE COUNTY STATION DOCKET NUMBER: 50-373 & 50-374 LOCATION OF FACILITY: MARSEILLES, IL REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

MEDIUM OR REQUIRED LOCATIONS LOCATION NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSES ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS SURFACE WATER GR-B 24 4 7.7 7 7.7 L-40 INDICATOR 0 (PCI/LITER) (12/12) (12/12) (12/12) ILLINOIS RIVER - DOWNSTREAM 4.6 - 10.7 3.0 - 10.0 4.6 - 10.7 5.2 MILES NNW OF SITE H-3 8 200 <LLD 257 257 L-21 CONTROL 0 (1/4) (1/4) ILLINOIS RIVER AT SENECA - UPSTREAM 4.0 MILES NE OF SITE 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 12 200 <LLD <LLD - 0 (PCI/LITER)

GAMMA 12 MN-54 15 <LLD <LLD - 0 CO-58 15 <LLD <LLD - 0 FE-59 30 <LLD <LLD - 0 CO-60 15 <LLD <LLD - 0 ZN-65 30 <LLD <LLD - 0 NB-95 15 <LLD <LLD - 0 ZR-95 30 <LLD <LLD - 0 CS-134 15 <LLD <LLD - 0 CS-137 18 <LLD <LLD - 0 BA-140 60 <LLD <LLD - 0 LA-140 15 <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values (values MDC). (F) Fraction of detectable measurement are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LASALLE COUNTY STATION, 2020 NAME OF FACILITY: LASALLE COUNTY STATION DOCKET NUMBER: 50-373 & 50-374 LOCATION OF FACILITY: MARSEILLES, IL REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

MEDIUM OR REQUIRED LOCATIONS LOCATION NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSES ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS FISH GAMMA 12 (PCI/KG WET) 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 A-2 LA-140 NA <LLD <LLD - 0 SEDIMENT GAMMA 6 (PCI/KG DRY) 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 464 10 17 17 17 L-07 INDICATOR 0 (E-3 PCI/CU.METER) (411/412) (52/52) (52/52) SENECA 6 - 35 9 - 36 7 - 30 5.2 MILES NNE OF SITE AIR PARTICULATE GAMMA 36 (E-3 PCI/CU.METER) MN-54 NA <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values (values MDC). (F) Fraction of detectable measurement are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LASALLE COUNTY STATION, 2020 NAME OF FACILITY: LASALLE COUNTY STATION DOCKET NUMBER: 50-373 & 50-374 LOCATION OF FACILITY: MARSEILLES, IL REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

MEDIUM OR REQUIRED LOCATIONS LOCATION NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSES ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS 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 50 <LLD <LLD - 0 CS-137 60 <LLD <LLD - 0 BA-140 NA <LLD <LLD - 0 LA-140 NA <LLD <LLD - 0 A-3 AIR IODINE GAMMA 464 (E-3 PCI/CU.METER) I-131 70 <LLD <LLD - 0 MILK I-131 19 1 NA <LLD - 0 (PCI/LITER)

GAMMA 19 MN-54 NA NA <LLD - 0 CO-58 NA NA <LLD - 0 FE-59 NA NA <LLD - 0 CO-60 NA NA <LLD - 0 ZN-65 NA NA <LLD - 0 NB-95 NA NA <LLD - 0 ZR-95 NA NA <LLD - 0 CS-134 15 NA <LLD - 0 CS-137 18 NA <LLD - 0 BA-140 60 NA <LLD - 0 LA-140 15 NA <LLD - 0 FOOD PRODUCTS GAMMA 12 (PCI/KG WET) MN-54 NA <LLD <LLD - 0 (M) The Mean Values are calculated using the positive values (values MDC). (F) Fraction of detectable measurement are indicated in parentheses.

TABLE A-1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANNUAL

SUMMARY

FOR THE LASALLE COUNTY STATION, 2020 NAME OF FACILITY: LASALLE COUNTY STATION DOCKET NUMBER: 50-373 & 50-374 LOCATION OF FACILITY: MARSEILLES, IL REPORTING PERIOD: 2020 INDICATOR CONTROL LOCATION WITH HIGHEST ANNUAL MEAN (M)

MEDIUM OR REQUIRED LOCATIONS LOCATION NUMBER OF PATHWAY SAMPLED TYPES OF NUMBER OF LOWER LIMIT MEAN (M) MEAN (M) MEAN (M) STATION # NONROUTINE (UNIT OF ANALYSES ANALYSES OF DETECTION (F) (F) (F) NAME REPORTED MEASUREMENT) PERFORMED PERFORMED (LLD) RANGE RANGE RANGE DISTANCE AND DIRECTION MEASUREMENTS 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 - 0 A-4 VEGETATION GAMMA 46 (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 - 0 DIRECT RADIATION OSLD-QUARTERLY 167 NA 16.8 14.4 19.1 L-210 INDICATOR 0 (MILLI-ROENTGEN/QTR.) (163/163) (4/4) (4/4) 5.9 - 23.5 6.7 - 20.0 10.4 - 23.5 3.3 MILES SW (M) The Mean Values are calculated using the positive values (values MDC). (F) Fraction of detectable measurement are indicated in parentheses.

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, LaSalle County Station, 2020 Location Location Description Distance & Direction From Site A. Surface Water L-21 Illinois River at Seneca, Upstream (control) 4.0 miles NE L-40 Illinois River, Downstream (indicator) 5.2 miles NNW B. Ground/Well Water L-27 LSCS Onsite Well (indicator) 0 miles at station L-28-W4 Marseilles Well (control) 7.0 miles NNW L-28-W5 Marseilles Well (control) 6.7 miles NNW L-28-W6 Marseilles Well (indicator) 4.1 miles N C. Milk - bi-weekly / monthly L-42 Biros Farm (control) 14.2 miles E D. Air Particulates / Air Iodine L-01 Nearsite 1 (indicator) 1.5 miles NNW L-03 Onsite 3 (indicator) 1.0 miles ENE L-04 Rte. 170 (indicator) 3.2 miles E L-05 Onsite 5 (indicator) 0.3 miles ESE L-06 Nearsite 6 (indicator) 0.4 miles W L-07 Seneca (indicator) 5.2 miles NNE L-08 Marseilles (indicator) 6.0 miles NNW L-10 Streator (control) 13.5 miles SW L-11A Ransom (indicator) 6.0 miles S E. Fish L-34 LaSalle Cooling Lake (indicator) 2.0 miles E L-35 Marseilles Pool of Illinois River, Downstream (indicator) 6.5 miles NNW L-36 Illinois River, Upstream of Discharge (control) 4.3 miles NE F. Sediment L-21 Illinois River at Seneca, Upstream (control) 4.0 miles NE L-40 Illinois River, Downstream (indicator) 5.2 miles NNW L-41 Illinois River, Downstream (indicator) 4.6 miles N G. Food Products Quadrant 1 171 Valley View, Seneca IL 5.2 miles NE Quadrant 1 281 E. Lincoln, Seneca IL 5.1 miles NE Quadrant 2 106 W. Thomas, Ransom, IL 6.0 miles S Quadrant 2 205 W. Plumb, Ransom IL 5.3 miles S Quadrant 3 1814 E. 25th Rd., Ransom IL 3.5 miles SW Quadrant 4 2507 N. 2553 Rd., Marseilles IL 4.3 miles NNW Control Biros Farm 14.2 miles E H. Vegetation L-Veg C Control 9.5 miles ENE L-ESE 1 Indicator 1.5 miles ESE L-ESE 2 Indicator 6.0 miles ESE B-1

TABLE B-1: Radiological Environmental Monitoring Program - Sampling Locations, Distance and Direction, LaSalle County Station, 2020 Location Location Description Distance & Direction From Site I. Environmental Dosimetry - OSLD Inner Ring L-101-1 and -2 0.5 miles N L-102-1 and -2 0.6 miles NNE L-103-1 and -2 0.7 miles NE L-104-1 and -2 0.8 miles ENE L-105-1 and -2 0.7 miles E L-106-1 and -2 1.4 miles ESE L-107-1 and -2 0.8 miles SE L-108-1 and -2 0.5 miles SSE L-109-1 and -2 0.6 miles S L-110-1 and -2 0.6 miles SSW L-111b-1 and -2 0.8 miles SW L-112-1 and -2 0.9 miles WSW L-113a-1 and -2 0.8 miles W L-114-1 and -2 0.9 miles WNW L-115-1 and -2 0.7 miles NW L-116-1 and -2 0.6 miles NNW Outer Ring L-201-3 and -4 4.0 miles N L-202-3 and -4 3.6 miles NNE L-203-1 and -2 4.0 miles NE L-204-1 and -2 3.2 miles ENE L-205A-1 and -2 3.2 miles ESE L-205B-3 and -4 5.1 miles E L-206-1 and -2 4.3 miles SE L-207-1 and -2 4.5 miles SSE L-208-1 and -2 4.5 miles S L-209-1 and -2 4.0 miles SSW L-210-1 and -2 3.3 miles SW L-211-1 and -2 4.5 miles WSW L-212-1 and -2 4.0 miles W L-213-3 and -4 4.9 miles W L-214-3 and -4 5.1 miles WNW L-215-3 and -4 5.0 miles NW L-216-3 and -4 5.0 miles NNW Other L-01-1 and -2 Nearsite 1 (indicator) 1.5 miles NNW L-03-1 and -2 Onsite 3 (indicator) 1.0 miles ENE L-04-1 and -2 Rte. 170 (indicator) 3.2 miles E L-05-1 and -2 Onsite 5 (indicator) 0.3 miles ESE L-06-1 and -2 Nearsite 6 (indicator) 0.4 miles W L-07-1 and -2 Seneca (indicator) 5.2 miles NNE L-08-1 and -2 Marseilles (indicator) 6.0 miles NNW L-11A-1 and -2 Ransom (indicator) 6.0 miles S Control and Special Interest L-10-1 and -2 Streator 13.5 miles SW B-2

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

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

Quarterly composite from TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation Surface Water Tritium weekly grab samples.

Ground/Well Gamma TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Quarterly grab samples.

Water Spectroscopy Ground/Well TBE, TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation Tritium Quarterly grab samples.

Water Semi-annual samples Gamma TBE-2007 Gamma-Emitting Radioisotope Analysis Fish collected via electroshocking Spectroscopy or other techniques Gamma Semi-annual TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Sediment Spectroscopy grab samples One-week composite of Air TBE, TBE-2008 Gross Alpha and/or Gross Beta Activity in Various Matrices Gross Beta continuous air sampling Particulates through glass fiber filter paper Air Gamma Quarterly composite of each TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Particulates Spectroscopy station Bi-weekly composite of Gamma TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Air Iodine continuous air sampling Spectroscopy through charcoal filter Bi-weekly grab sample when TBE, TBE-2012 Radioiodine in Various Matrices Milk I-131 cows are on pasture.

Monthly all other times Bi-weekly grab sample when Gamma Milk cows are on pasture. TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Spectroscopy Monthly all other times Food Gamma TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Annual grab samples.

Products Spectroscopy Gamma Monthly grab samples during TBE, TBE-2007 Gamma-Emitting Radioisotope Analysis Vegetation Spectroscopy growing season Optically Quarterly OSLDs comprised Stimulated OSLD of two Al2O3:C Landauer Landauer Incorporated Luminescence Incorporated elements.

Dosimetry B-3

B-4 Figure B-1 Inner Ring OSLD Locations of the LaSalle County Station, 2020

Figure B-2 Outer Ring OSLD Locations and Fixed Air Sampling Locations of the LaSalle County Station, 2020 B-5

Figure B-3 Ingestion and Waterborne Exposure Pathway Sample Locations of the LaSalle County Station, 2020 B-6

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 LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD L-21 L-40 01/02/20 - 01/30/20 5.6 +/- 2.0 5.1 +/- 2.0 02/05/20 - 02/27/20 3.3 +/- 2.2 4.6 +/- 2.3 03/04/20 - 03/26/20 8.9 +/- 2.7 7.3 +/- 2.6 04/01/20 - 04/30/20 7.5 +/- 2.8 10.0 +/- 2.8 05/06/20 - 05/28/20 3.0 +/- 1.9 6.1 +/- 2.3 06/03/20 - 06/25/20 8.6 +/- 2.5 7.2 +/- 2.4 07/01/20 - 07/29/20 5.7 +/- 2.0 7.1 +/- 2.1 08/05/20 - 08/27/20 6.4 +/- 2.2 7.7 +/- 2.3 09/02/20 - 09/30/20 9.1 +/- 2.4 10.3 +/- 2.5 10/07/20 - 10/29/20 7.6 +/- 2.3 8.1 +/- 2.3 11/04/20 - 11/25/20 10.0 +/- 2.5 10.7 +/- 2.5 12/02/20 - 12/30/20 8.7 +/- 2.2 8.5 +/- 2.3 (1) MEAN +/- 2 STD DEV 7.0 +/- 4.5 7.7 +/- 3.9 Table C-I.2 CONCENTRATIONS OF TRITIUM IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD L-21 L-40 01/02/20 - 03/26/20 < 195 < 195 04/01/20 - 06/25/20 < 189 < 190 07/01/20 - 09/30/20 < 187 < 188 10/07/20 - 12/30/20 257 +/- 123 < 180 (1) MEAN +/- 2 STD DEV 257 +/- 0 -

(1) THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES (VALUES MDC)

C-1

Table C-I.3 CONCENTRATIONS OF GAMMA EMITTERS IN SURFACE WATER SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-21 01/02/20 - 01/30/20 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 9 < 2 < 2 < 16 < 5 02/05/20 - 02/27/20 < 2 < 3 < 5 < 3 < 5 < 3 < 4 < 9 < 3 < 2 < 20 < 7 03/04/20 - 03/26/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 9 < 2 < 2 < 17 < 6 04/01/20 - 04/30/20 < 2 < 3 < 9 < 2 < 3 < 3 < 6 < 2048 < 2 < 2 < 461 < 151 05/06/20 - 05/28/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 7 < 2 < 2 < 14 < 5 06/03/20 - 06/25/20 < 2 < 3 < 6 < 2 < 5 < 3 < 5 < 9 < 3 < 3 < 19 < 7 07/01/20 - 07/29/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 13 < 2 < 2 < 22 < 7 08/05/20 - 08/27/20 < 4 < 4 < 8 < 4 < 9 < 4 < 8 < 15 < 4 < 4 < 30 < 11 09/02/20 - 09/30/20 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 9 < 2 < 2 < 16 < 5 10/07/20 - 10/29/20 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 7 < 2 < 2 < 14 < 5 11/04/20 - 11/25/20 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 8 < 2 < 2 < 14 < 5 12/02/20 - 12/30/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 10 < 2 < 2 < 17 < 6 MEAN - - - - - - - - - - - -

C-2 L-40 01/02/20 - 01/30/20 < 1 < 2 < 4 < 2 < 3 < 2 < 3 < 8 < 2 < 2 < 15 < 5 02/05/20 - 02/27/20 < 3 < 3 < 6 < 3 < 5 < 3 < 5 < 11 < 3 < 3 < 22 < 7 03/04/20 - 03/26/20 < 3 < 3 < 6 < 2 < 5 < 3 < 5 < 11 < 3 < 3 < 21 < 7 04/01/20 - 04/30/20 < 2 < 3 < 11 < 2 < 4 < 4 < 7 < 2374 < 2 < 2 < 520 < 170 05/06/20 - 05/28/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 8 < 2 < 2 < 17 < 5 06/03/20 - 06/25/20 < 3 < 3 < 7 < 3 < 6 < 4 < 5 < 11 < 3 < 3 < 21 < 7 07/01/20 - 07/29/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 12 < 2 < 2 < 20 < 7 08/05/20 - 08/27/20 < 4 < 4 < 8 < 4 < 6 < 3 < 7 < 15 < 4 < 4 < 29 < 9 09/02/20 - 09/30/20 < 1 < 2 < 4 < 2 < 3 < 2 < 3 < 9 < 2 < 2 < 16 < 5 10/07/20 - 10/29/20 < 2 < 2 < 5 < 2 < 4 < 3 < 4 < 8 < 3 < 2 < 17 < 6 11/04/20 - 11/25/20 < 2 < 2 < 5 < 2 < 4 < 2 < 3 < 8 < 2 < 2 < 16 < 5 12/02/20 - 12/30/20 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 11 < 2 < 2 < 21 < 6 MEAN - - - - - - - - - - - -

BOLD = Client-required detection limits not met due to age of sample at time of analysis

Table C-II.1 CONCENTRATIONS OF TRITIUM IN GROUND/WELL WATER SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION PERIOD L-27 L-28-W4 L-28-W5 L-28-W6 01/09/20 - 01/09/20 < 177 < 179 < 179 04/08/20 - 04/08/20 < 190 05/28/20 - 05/28/20 < 181 < 181 07/08/20 - 07/08/20 < 190 < 188 < 186 10/07/20 - 10/07/20 < 184 < 187 < 186 MEAN - - - -

C-3

Table C-II.2 CONCENTRATIONS OF GAMMA EMITTERS IN GROUND/WELL WATER SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-27 01/09/20 - 01/09/20 < 7 < 7 < 15 < 7 < 13 < 8 < 13 < 8 < 6 < 29 < 12 04/08/20 - 04/08/20 < 8 < 6 < 15 < 7 < 21 < 8 < 15 < 6 < 8 < 37 < 14 07/08/20 - 07/08/20 < 6 < 7 < 14 < 8 < 14 < 7 < 10 < 7 < 6 < 32 < 9 10/07/20 - 10/07/20 < 10 < 6 < 15 < 10 < 18 < 9 < 13 < 9 < 8 < 32 < 11 MEAN - - - - - - - - - - -

L-28-W4 05/28/20 - 05/28/20 < 8 < 5 < 16 < 9 < 12 < 7 < 14 < 9 < 8 < 29 < 12 10/07/20 - 10/07/20 < 6 < 6 < 13 < 7 < 13 < 7 < 10 < 7 < 6 < 30 < 12 MEAN - - - - - - - - - - -

L-28-W5 01/09/20 - 01/09/20 < 6 < 7 < 13 < 7 < 15 < 9 < 13 < 5 < 8 < 32 < 8 07/08/20 - 07/08/20 < 5 < 5 < 13 < 5 < 11 < 7 < 11 < 6 < 7 < 32 < 11 C-4 MEAN - - - - - - - - - - -

L-28-W6 01/09/20 - 01/09/20 < 8 < 8 < 17 < 8 < 16 < 7 < 12 < 8 < 9 < 32 < 14 05/28/20 - 05/28/20 < 6 < 6 < 11 < 7 < 12 < 6 < 11 < 7 < 6 < 30 < 10 07/08/20 - 07/08/20 < 7 < 6 < 11 < 6 < 12 < 5 < 8 < 6 < 5 < 28 < 10 10/07/20 - 10/07/20 < 6 < 6 < 13 < 8 < 10 < 6 < 11 < 8 < 7 < 35 < 12 MEAN - - - - - - - - - - -

Table C-III.1 CONCENTRATIONS OF GAMMA EMITTERS IN FISH SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 Cs-134 Cs-137 Ba-140 La-140 L-34 Channel Catfish 05/12/20 < 53 < 43 < 101 < 46 < 86 < 41 < 98 < 48 < 50 < 268 < 76 Largemouth Bass 05/12/20 < 32 < 27 < 70 < 34 < 72 < 28 < 59 < 30 < 36 < 157 < 56 Largemouth Bass 10/07/20 < 55 < 48 < 118 < 42 < 111 < 46 < 84 < 49 < 48 < 213 < 51 Channel Catfish 10/07/20 < 40 < 47 < 93 < 52 < 97 < 37 < 74 < 55 < 44 < 242 < 82 MEAN - - - - - - - - - - -

L-35 Channel Catfish 05/12/20 < 80 < 63 < 136 < 54 < 118 < 69 < 115 < 77 < 76 < 430 < 114 Freshwater Drum 05/12/20 < 42 < 37 < 86 < 41 < 79 < 43 < 66 < 42 < 42 < 205 < 69 Channel Catfish 10/07/20 < 47 < 45 < 92 < 40 < 86 < 54 < 88 < 54 < 41 < 242 < 79 Smallmouth Buffalo 10/07/20 < 56 < 63 < 121 < 71 < 134 < 73 < 93 < 72 < 66 < 311 < 120 C-5 MEAN - - - - - - - - - - -

L-36 Freshwater Drum 05/12/20 < 39 < 36 < 85 < 51 < 88 < 41 < 71 < 39 < 43 < 209 < 66 Smallmouth Buffalo 05/12/20 < 44 < 46 < 109 < 45 < 91 < 54 < 84 < 48 < 55 < 268 < 82 Channel Catfish 10/07/20 < 64 < 64 < 146 < 72 < 147 < 69 < 91 < 79 < 64 < 273 < 61 Smallmouth Bass 10/07/20 < 43 < 50 < 94 < 42 < 91 < 48 < 111 < 44 < 51 < 252 < 65 MEAN - - - - - - - - - - -

Table C-IV.1 CONCENTRATIONS OF GAMMA EMITTERS IN SEDIMENT SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/KG DRY +/- 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 L-21 06/08/20 < 99 < 60 < 167 < 85 < 242 < 115 < 123 < 103 < 133 < 330 < 123 10/13/20 < 76 < 89 < 173 < 102 < 165 < 92 < 161 < 101 < 90 < 384 < 86 MEAN - - - - - - - - - - -

L-40 06/08/20 < 85 < 88 < 185 < 97 < 217 < 83 < 125 < 98 < 98 < 313 < 89 10/13/20 < 42 < 46 < 106 < 43 < 100 < 53 < 69 < 48 < 45 < 228 < 65 MEAN - - - - - - - - - - -

L-41 06/08/20 < 51 < 49 < 114 < 52 < 122 < 55 < 85 < 43 < 61 < 205 < 48 10/13/20 < 45 < 35 < 97 < 49 < 111 < 51 < 84 < 56 < 41 < 206 < 56 MEAN - - - - - - - - - - -

C-6

Table C-V.1 CONCENTRATIONS OF GROSS BETA IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III GROUP IV PERIOD L-03 L-05 L-01 L-06 L-04 L-07 L-08 L-11A L-10 01/02/20 - 01/09/20 13 +/- 4 13 +/- 4 12 +/- 4 14 +/- 4 13 +/- 4 15 +/- 4 13 +/- 4 11 +/- 4 15 +/- 4 01/09/20 - 01/16/20 16 +/- 4 15 +/- 4 15 +/- 4 16 +/- 4 14 +/- 4 19 +/- 4 14 +/- 4 20 +/- 4 12 +/- 4 01/16/20 - 01/23/20 23 +/- 5 22 +/- 5 17 +/- 4 20 +/- 5 18 +/- 4 26 +/- 5 19 +/- 4 21 +/- 5 21 +/- 5 01/23/20 - 01/30/20 13 +/- 4 14 +/- 4 11 +/- 4 15 +/- 4 17 +/- 4 13 +/- 4 16 +/- 4 15 +/- 4 11 +/- 4 01/30/20 - 02/05/20 10 +/- 4 10 +/- 4 10 +/- 4 7 +/- 4 7 +/- 4 14 +/- 5 8 +/- 4 8 +/- 4 11 +/- 4 02/05/20 - 02/13/20 11 +/- 3 12 +/- 3 11 +/- 3 10 +/- 3 12 +/- 3 12 +/- 3 14 +/- 3 11 +/- 3 15 +/- 4 02/13/20 - 02/20/20 15 +/- 5 13 +/- 4 10 +/- 4 11 +/- 4 14 +/- 5 13 +/- 4 9 +/- 4 14 +/- 4 13 +/- 4 02/20/20 - 02/27/20 21 +/- 4 21 +/- 4 18 +/- 4 26 +/- 5 22 +/- 5 21 +/- 5 30 +/- 5 23 +/- 5 21 +/- 4 02/27/20 - 03/04/20 11 +/- 4 12 +/- 4 17 +/- 5 11 +/- 4 16 +/- 5 17 +/- 5 10 +/- 4 14 +/- 4 12 +/- 4 03/04/20 - 03/12/20 16 +/- 4 15 +/- 4 13 +/- 4 16 +/- 4 15 +/- 4 12 +/- 4 16 +/- 4 14 +/- 4 13 +/- 4 03/12/20 - 03/19/20 12 +/- 3 13 +/- 3 10 +/- 3 15 +/- 3 11 +/- 3 12 +/- 3 14 +/- 3 12 +/- 3 11 +/- 3 03/19/20 - 03/26/20 11 +/- 4 8 +/- 4 11 +/- 4 12 +/- 4 10 +/- 4 9 +/- 4 12 +/- 4 8 +/- 4 13 +/- 5 03/26/20 - 04/01/20 8 +/- 4 12 +/- 4 9 +/- 4 11 +/- 5 11 +/- 5 12 +/- 5 9 +/- 4 8 +/- 4 9 +/- 4 04/01/20 - 04/08/20 10 +/- 4 13 +/- 4 14 +/- 4 16 +/- 4 13 +/- 4 11 +/- 4 13 +/- 4 14 +/- 4 13 +/- 4 04/08/20 - 04/16/20 (1) 15 +/- 3 17 +/- 4 16 +/- 3 19 +/- 4 18 +/- 4 18 +/- 4 13 +/- 3 16 +/- 3 04/16/20 - 04/23/20 16 +/- 4 9 +/- 4 12 +/- 4 15 +/- 4 15 +/- 4 15 +/- 4 11 +/- 4 13 +/- 4 17 +/- 4 04/23/20 - 04/30/20 13 +/- 4 11 +/- 4 13 +/- 4 15 +/- 4 14 +/- 4 12 +/- 4 13 +/- 4 14 +/- 4 16 +/- 4 04/30/20 - 05/06/20 8 +/- 4 6 +/- 4 6 +/- 4 8 +/- 4 7 +/- 4 7 +/- 4 < 6 7 +/- 4 9 +/- 4 05/06/20 - 05/14/20 10 +/- 3 9 +/- 3 10 +/- 3 11 +/- 3 12 +/- 4 8 +/- 3 10 +/- 3 10 +/- 3 10 +/- 3 05/14/20 - 05/21/20 8 +/- 4 9 +/- 4 9 +/- 4 9 +/- 4 9 +/- 4 6 +/- 4 9 +/- 4 9 +/- 4 10 +/- 4 05/21/20 - 05/28/20 10 +/- 4 11 +/- 4 7 +/- 3 10 +/- 4 9 +/- 3 17 +/- 7 9 +/- 3 9 +/- 4 9 +/- 4 05/28/20 - 06/03/20 9 +/- 4 8 +/- 4 8 +/- 4 10 +/- 4 7 +/- 4 11 +/- 4 9 +/- 4 11 +/- 4 12 +/- 4 06/03/20 - 06/11/20 16 +/- 4 16 +/- 4 15 +/- 4 12 +/- 3 15 +/- 4 13 +/- 4 11 +/- 3 13 +/- 4 14 +/- 4 06/11/20 - 06/18/20 17 +/- 5 15 +/- 4 16 +/- 4 17 +/- 4 17 +/- 5 13 +/- 4 13 +/- 4 14 +/- 4 18 +/- 5 06/18/20 - 06/25/20 19 +/- 5 20 +/- 5 22 +/- 5 20 +/- 4 22 +/- 5 16 +/- 4 22 +/- 5 21 +/- 5 21 +/- 4 06/25/20 - 07/01/20 13 +/- 5 15 +/- 5 9 +/- 4 12 +/- 4 18 +/- 5 12 +/- 4 13 +/- 5 11 +/- 4 12 +/- 5 07/01/20 - 07/08/20 17 +/- 4 18 +/- 4 25 +/- 5 20 +/- 4 24 +/- 5 23 +/- 4 24 +/- 5 19 +/- 4 21 +/- 4 07/08/20 - 07/16/20 20 +/- 4 21 +/- 4 16 +/- 4 18 +/- 4 18 +/- 4 21 +/- 4 21 +/- 4 20 +/- 4 15 +/- 4 07/16/20 - 07/23/20 24 +/- 5 17 +/- 4 15 +/- 4 19 +/- 8 17 +/- 4 17 +/- 4 19 +/- 4 18 +/- 4 19 +/- 4 07/23/20 - 07/29/20 14 +/- 4 12 +/- 4 11 +/- 4 14 +/- 4 8 +/- 4 14 +/- 4 13 +/- 4 9 +/- 4 11 +/- 4 07/29/20 - 08/05/20 13 +/- 4 12 +/- 4 13 +/- 4 15 +/- 4 12 +/- 4 13 +/- 4 16 +/- 4 14 +/- 4 11 +/- 4 08/05/20 - 08/13/20 18 +/- 2 27 +/- 5 17 +/- 4 22 +/- 4 26 +/- 4 24 +/- 5 21 +/- 4 22 +/- 4 26 +/- 5 08/13/20 - 08/20/20 (1) 17 +/- 4 20 +/- 4 22 +/- 4 22 +/- 4 20 +/- 4 21 +/- 4 19 +/- 4 19 +/- 4 08/20/20 - 08/27/20 (1) 23 +/- 5 25 +/- 5 30 +/- 5 24 +/- 5 29 +/- 5 26 +/- 5 23 +/- 5 27 +/- 5 08/27/20 - 09/02/20 24 +/- 5 20 +/- 5 21 +/- 5 20 +/- 5 18 +/- 5 20 +/- 5 21 +/- 5 19 +/- 5 17 +/- 5 09/02/20 - 09/10/20 11 +/- 4 9 +/- 3 12 +/- 3 11 +/- 3 13 +/- 3 13 +/- 3 13 +/- 3 15 +/- 4 16 +/- 4 09/10/20 - 09/17/20 16 +/- 4 15 +/- 4 16 +/- 4 13 +/- 4 16 +/- 4 20 +/- 4 15 +/- 4 14 +/- 4 20 +/- 4 09/17/20 - 09/24/20 27 +/- 5 25 +/- 5 22 +/- 4 23 +/- 5 28 +/- 5 27 +/- 5 25 +/- 5 17 +/- 4 27 +/- 5 09/24/20 - 09/30/20 14 +/- 5 17 +/- 5 13 +/- 5 15 +/- 5 13 +/- 5 18 +/- 5 15 +/- 5 16 +/- 5 13 +/- 5 09/30/20 - 10/07/20 14 +/- 4 16 +/- 4 14 +/- 4 15 +/- 4 15 +/- 4 14 +/- 4 13 +/- 4 15 +/- 4 12 +/- 4 10/07/20 - 10/15/20 19 +/- 4 20 +/- 4 19 +/- 4 21 +/- 4 23 +/- 4 24 +/- 5 23 +/- 4 18 +/- 4 29 +/- 5 10/15/20 - 10/22/20 20 +/- 5 17 +/- 5 21 +/- 5 15 +/- 4 14 +/- 5 19 +/- 5 19 +/- 5 17 +/- 6 16 +/- 5 10/22/20 - 10/29/20 21 +/- 4 16 +/- 4 20 +/- 4 21 +/- 4 18 +/- 4 18 +/- 4 15 +/- 4 16 +/- 4 17 +/- 4 10/29/20 - 11/04/20 25 +/- 6 29 +/- 6 23 +/- 5 26 +/- 5 27 +/- 6 29 +/- 6 25 +/- 5 21 +/- 5 22 +/- 5 11/04/20 - 11/12/20 19 +/- 4 20 +/- 4 23 +/- 4 25 +/- 4 19 +/- 4 21 +/- 4 26 +/- 4 20 +/- 4 20 +/- 4 11/12/20 - 11/19/20 21 +/- 4 18 +/- 4 20 +/- 4 18 +/- 4 19 +/- 4 20 +/- 4 22 +/- 4 25 +/- 5 23 +/- 4 11/19/20 - 11/25/20 21 +/- 5 21 +/- 5 25 +/- 5 22 +/- 5 20 +/- 5 24 +/- 5 29 +/- 5 25 +/- 5 22 +/- 5 11/25/20 - 12/02/20 18 +/- 4 15 +/- 4 17 +/- 4 14 +/- 4 15 +/- 4 18 +/- 4 16 +/- 4 13 +/- 4 16 +/- 4 12/02/20 - 12/10/20 31 +/- 5 30 +/- 5 32 +/- 5 32 +/- 5 35 +/- 5 30 +/- 5 29 +/- 5 35 +/- 5 36 +/- 5 12/10/20 - 12/17/20 20 +/- 5 19 +/- 4 22 +/- 5 23 +/- 4 20 +/- 5 27 +/- 5 23 +/- 5 22 +/- 5 23 +/- 5 12/17/20 - 12/23/20 31 +/- 6 26 +/- 5 27 +/- 5 30 +/- 5 26 +/- 5 30 +/- 5 29 +/- 5 32 +/- 5 30 +/- 6 12/23/20 - 12/30/20 17 +/- 5 13 +/- 4 (1) 11 +/- 4 13 +/- 4 14 +/- 4 16 +/- 4 15 +/- 4 15 +/- 4 (2) MEAN +/- 2 STD DEV 16 +/- 11 16 +/- 11 16 +/- 12 17 +/- 12 17 +/- 12 17 +/- 12 17 +/- 12 16 +/- 12 17 +/- 12 (1) SEE PROGRAM EXCEPTIONS SECTION FOR EXPLANATION (2) THE MEAN AND TWO STANDARD DEVIATION ARE CALCULATED USING THE POSITIVE VALUES (VALUES MDC)

C-7

Table C-V.2 MONTHLY AND YEARLY MEAN VALUES OF GROSS BETA CONCENTRATIONS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA GROUP I - ONSITE LOCATIONS GROUP II - NEAR-SITE LOCATIONS GROUP III - FAR-FIELD LOCATIONS GROUP IV - CONTROL LOCATION COLLECTION MIN MAX MEAN +/- COLLECTION MIN MAX MEAN +/- COLLECTION MIN MAX MEAN +/- COLLECTION MIN MAX MEAN +/-

PERIOD 2SD PERIOD 2SD PERIOD 2SD PERIOD 2SD 01/02/20 - 01/30/20 13 23 16 +/- 8 01/02/20 - 01/30/20 11 20 15 +/- 5 01/02/20 - 01/30/20 11 26 16 +/- 8 01/02/20 - 01/30/20 11 21 15 +/- 9 01/30/20 - 02/27/20 10 21 14 +/- 9 01/30/20 - 02/27/20 7 26 13 +/- 12 01/30/20 - 02/27/20 7 30 14 +/- 13 01/30/20 - 02/27/20 11 21 15 +/- 8 02/27/20 - 04/01/20 8 16 12 +/- 5 02/27/20 - 04/01/20 9 17 12 +/- 5 02/27/20 - 04/01/20 8 17 12 +/- 5 02/27/20 - 04/01/20 9 13 12 +/- 3 04/01/20 - 04/30/20 9 16 12 +/- 5 04/01/20 - 04/30/20 12 17 15 +/- 4 04/01/20 - 04/30/20 11 19 14 +/- 5 04/01/20 - 04/30/20 13 17 15 +/- 4 04/30/20 - 06/03/20 6 11 9 +/- 3 04/30/20 - 06/03/20 6 11 9 +/- 3 04/30/20 - 06/03/20 6 17 9 +/- 5 04/30/20 - 06/03/20 9 12 10 +/- 3 06/03/20 - 07/01/20 13 20 16 +/- 4 06/03/20 - 07/01/20 9 22 15 +/- 8 06/03/20 - 07/01/20 11 22 15 +/- 8 06/03/20 - 07/01/20 12 21 16 +/- 8 07/01/20 - 07/29/20 12 24 18 +/- 8 07/01/20 - 07/29/20 11 25 17 +/- 8 07/01/20 - 07/29/20 8 24 18 +/- 10 07/01/20 - 07/29/20 11 21 17 +/- 9 07/29/20 - 09/02/20 12 27 19 +/- 10 07/29/20 - 09/02/20 13 30 21 +/- 10 07/29/20 - 09/02/20 12 29 20 +/- 9 07/29/20 - 09/02/20 11 27 20 +/- 13 09/02/20 - 09/30/20 9 27 17 +/- 13 09/02/20 - 09/30/20 11 23 16 +/- 9 09/02/20 - 09/30/20 13 28 17 +/- 10 09/02/20 - 09/30/20 13 27 19 +/- 12 09/30/20 - 10/29/20 14 21 18 +/- 5 09/30/20 - 10/29/20 14 21 18 +/- 6 09/30/20 - 10/29/20 13 24 18 +/- 7 09/30/20 - 10/29/20 12 29 19 +/- 14 10/29/20 - 12/02/20 15 29 21 +/- 8 10/29/20 - 12/02/20 14 26 21 +/- 8 10/29/20 - 12/02/20 13 29 22 +/- 9 10/29/20 - 12/02/20 16 23 21 +/- 5 12/02/20 - 12/30/20 13 31 23 +/- 14 12/02/20 - 12/30/20 11 32 26 +/- 15 12/02/20 - 12/30/20 13 35 25 +/- 15 12/02/20 - 12/30/20 15 36 26 +/- 18 C-8 01/02/20 - 12/30/20 6 31 16 +/- 11 01/02/20 - 12/30/20 6 32 16 +/- 12 01/02/20 - 12/30/20 6 35 17 +/- 12 01/02/20 - 12/30/20 9 36 17 +/- 12

Table C-V.3 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-01 01/02/20 - 04/01/20 < 4 < 5 < 13 < 4 < 8 < 6 < 11 < 4 < 3 < 231 < 94 04/01/20 - 07/01/20 < 2 < 3 < 10 < 2 < 4 < 3 < 5 < 2 < 2 < 141 < 46 07/01/20 - 09/30/20 < 2 < 4 < 12 < 2 < 4 < 3 < 6 < 2 < 1 < 153 < 104 09/30/20 - 12/23/20 < 3 < 4 < 10 < 2 < 7 < 3 < 7 < 2 < 2 < 189 < 89 MEAN - - - - - - - - - - -

L-03 01/02/20 - 04/01/20 < 3 < 3 < 6 < 2 < 7 < 3 < 7 < 3 < 2 < 180 < 75 04/01/20 - 07/01/20 < 2 < 4 < 6 < 3 < 6 < 4 < 6 < 2 < 3 < 164 < 81 07/01/20 - 09/30/20 < 3 < 4 < 16 < 3 < 6 < 5 < 7 < 3 < 2 < 412 < 83 09/30/20 - 12/30/20 < 2 < 4 < 9 < 3 < 5 < 3 < 6 < 2 < 2 < 92 < 50 MEAN - - - - - - - - - - -

L-04 01/02/20 - 04/01/20 < 3 < 3 < 11 < 3 < 4 < 4 < 6 < 2 < 2 < 120 < 29 C-9 04/01/20 - 07/01/20 < 3 < 4 < 11 < 3 < 5 < 5 < 7 < 3 < 2 < 190 < 76 07/01/20 - 09/30/20 < 3 < 5 < 14 < 2 < 7 < 6 < 9 < 3 < 2 < 254 < 133 09/30/20 - 12/30/20 < 3 < 4 < 11 < 3 < 7 < 4 < 7 < 4 < 3 < 158 < 72 MEAN - - - - - - - - - - -

L-05 01/02/20 - 04/01/20 < 2 < 3 < 12 < 3 < 7 < 4 < 6 < 2 < 2 < 105 < 45 04/01/20 - 07/01/20 < 2 < 4 < 12 < 2 < 5 < 2 < 5 < 2 < 2 < 112 < 55 07/01/20 - 09/30/20 < 3 < 3 < 15 < 2 < 5 < 4 < 8 < 2 < 2 < 283 < 139 09/30/20 - 12/30/20 < 4 < 6 < 18 < 5 < 11 < 6 < 10 < 4 < 4 < 290 < 94 MEAN - - - - - - - - - - -

L-06 01/02/20 - 04/01/20 < 2 < 3 < 10 < 1 < 6 < 4 < 5 < 2 < 1 < 141 < 84 04/01/20 - 07/01/20 < 3 < 5 < 13 < 3 < 7 < 4 < 6 < 2 < 2 < 177 < 91 07/01/20 - 09/30/20 < 4 < 6 < 22 < 3 < 10 < 6 < 12 < 4 < 4 < 403 < 186 09/30/20 - 12/30/20 < 3 < 3 < 13 < 2 < 6 < 4 < 7 < 3 < 2 < 166 < 50 MEAN - - - - - - - - - - -

Table C-V.3 CONCENTRATIONS OF GAMMA EMITTERS IN AIR PARTICULATE SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-07 01/02/20 - 04/01/20 < 3 < 4 < 10 < 2 < 5 < 5 < 8 < 3 < 2 < 183 < 59 04/01/20 - 07/01/20 < 2 < 3 < 13 < 1 < 5 < 3 < 6 < 2 < 2 < 162 < 70 07/01/20 - 09/30/20 < 3 < 5 < 10 < 3 < 8 < 4 < 8 < 3 < 3 < 251 < 112 09/30/20 - 12/30/20 < 2 < 2 < 4 < 1 < 5 < 3 < 5 < 2 < 2 < 128 < 51 MEAN - - - - - - - - - - -

L-08 01/02/20 - 04/01/20 < 2 < 3 < 5 < 1 < 5 < 4 < 5 < 2 < 2 < 124 < 65 04/01/20 - 07/01/20 < 3 < 4 < 11 < 2 < 7 < 5 < 7 < 3 < 3 < 163 < 35 07/01/20 - 09/30/20 < 2 < 3 < 11 < 1 < 7 < 4 < 6 < 1 < 2 < 253 < 94 09/30/20 - 12/30/20 < 3 < 5 < 14 < 3 < 6 < 4 < 8 < 2 < 2 < 168 < 70 MEAN - - - - - - - - - - -

L-10 01/02/20 - 04/01/20 < 3 < 3 < 11 < 3 < 8 < 4 < 6 < 3 < 2 < 174 < 41 C-10 04/01/20 - 07/01/20 < 4 < 7 < 18 < 4 < 10 < 6 < 11 < 4 < 4 < 286 < 138 07/01/20 - 09/30/20 < 2 < 2 < 9 < 1 < 6 < 4 < 5 < 2 < 2 < 214 < 70 09/30/20 - 12/30/20 < 4 < 6 < 17 < 5 < 9 < 5 < 10 < 4 < 3 < 230 < 133 MEAN - - - - - - - - - - -

L-11A 01/02/20 - 04/01/20 < 4 < 7 < 18 < 5 < 10 < 6 < 11 < 5 < 4 < 234 < 98 04/01/20 - 07/01/20 < 2 < 2 < 7 < 1 < 6 < 3 < 6 < 2 < 2 < 158 < 52 07/01/20 - 09/30/20 < 2 < 3 < 11 < 2 < 7 < 4 < 6 < 3 < 1 < 215 < 68 09/30/20 - 12/30/20 < 2 < 2 < 9 < 2 < 4 < 3 < 5 < 2 < 2 < 175 < 57 MEAN - - - - - - - - - - -

Table C-VI.1 CONCENTRATIONS OF I-131 IN AIR IODINE SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF E-3 PCI/CU METER +/- 2 SIGMA COLLECTION GROUP I GROUP II GROUP III GROUP IV PERIOD L-03 L-05 L-01 L-06 L-04 L-07 L-08 L-11A L-10 01/02/20 - 01/09/20 < 19 < 22 < 22 < 22 < 21 < 28 < 28 < 29 < 27 01/09/20 - 01/16/20 < 27 < 26 < 26 < 26 < 23 < 29 < 29 < 29 < 28 01/16/20 - 01/23/20 < 37 < 33 < 37 < 39 < 37 < 59 < 57 < 58 < 56 01/23/20 - 01/30/20 < 27 < 26 < 27 < 44 < 27 < 44 < 38 < 45 < 42 01/30/20 - 02/05/20 < 26 < 30 < 30 < 31 < 31 < 41 < 41 < 40 < 38 02/05/20 - 02/13/20 < 40 < 40 < 39 < 40 < 34 < 39 < 39 < 38 < 39 02/13/20 - 02/20/20 < 30 < 30 < 29 < 39 < 30 < 39 < 38 < 37 < 24 02/20/20 - 02/27/20 < 31 < 31 < 31 < 27 < 33 < 23 < 23 < 23 < 22 02/27/20 - 03/04/20 < 62 < 60 < 62 < 63 < 27 < 56 < 49 < 57 < 54 03/04/20 - 03/12/20 < 37 < 36 < 36 < 31 < 37 < 66 < 65 < 66 < 64 03/12/20 - 03/19/20 < 36 < 40 < 41 < 41 < 42 < 38 < 36 < 37 < 35 03/19/20 - 03/26/20 < 50 < 23 < 48 < 49 < 49 < 46 < 46 < 46 < 46 03/26/20 - 04/01/20 < 34 < 38 < 39 < 28 < 18 < 19 < 28 < 29 < 28 04/01/20 - 04/08/20 < 13 < 27 < 26 < 27 < 27 < 34 < 34 < 35 < 34 04/08/20 - 04/16/20 (1) < 45 < 45 < 22 < 49 < 47 < 45 < 46 < 45 04/16/20 - 04/23/20 < 22 < 44 < 45 < 44 < 45 < 50 < 50 < 49 < 48 04/23/20 - 04/30/20 < 43 < 41 < 39 < 52 < 43 < 26 < 53 < 55 < 54 04/30/20 - 05/06/20 < 28 < 45 < 47 < 47 < 49 < 65 < 28 < 65 < 64 05/06/20 - 05/14/20 < 15 < 25 < 25 < 25 < 26 < 29 < 30 < 30 < 30 05/14/20 - 05/21/20 < 26 < 46 < 43 < 43 < 45 < 66 < 66 < 68 < 66 05/21/20 - 05/28/20 < 14 < 14 < 14 < 48 < 8 < 54 < 48 < 50 < 49 05/28/20 - 06/03/20 < 47 < 45 < 47 < 39 < 45 < 40 < 40 < 23 < 40 06/03/20 - 06/11/20 < 38 < 37 < 37 < 41 < 36 < 43 < 23 < 42 < 42 06/11/20 - 06/18/20 < 40 < 38 < 39 < 31 < 39 < 32 < 31 < 32 < 13 06/18/20 - 06/25/20 < 62 < 60 < 25 < 58 < 62 < 43 < 28 < 44 < 43 06/25/20 - 07/01/20 < 33 < 31 < 33 < 18 < 34 < 51 < 51 < 52 < 51 07/01/20 - 07/08/20 < 49 < 48 < 46 < 25 < 44 < 37 < 37 < 39 < 38 07/08/20 - 07/16/20 < 31 < 31 < 31 < 30 < 13 < 20 < 20 < 20 < 20 07/16/20 - 07/23/20 < 43 < 42 < 41 < 66 < 42 < 54 < 55 < 56 < 56 07/23/20 - 07/29/20 < 42 < 43 < 41 < 41 < 17 < 27 < 64 < 68 < 64 07/29/20 - 08/05/20 < 54 < 53 < 54 < 25 < 56 < 55 < 56 < 57 < 55 08/05/20 - 08/13/20 < 16 < 21 < 40 < 39 < 39 < 24 < 43 < 47 < 48 08/13/20 - 08/20/20 (1) < 49 < 48 < 47 < 49 < 47 < 47 < 31 < 47 08/20/20 - 08/27/20 (1) < 10 < 23 < 23 < 24 < 65 < 65 < 29 < 66 08/27/20 - 09/02/20 < 61 < 64 < 66 < 43 < 28 < 44 < 44 < 21 < 44 09/02/20 - 09/10/20 < 25 < 47 < 46 < 22 < 46 < 9 < 22 < 22 < 22 09/10/20 - 09/17/20 < 58 < 25 < 58 < 58 < 59 < 32 < 32 < 32 < 32 09/17/20 - 09/24/20 < 23 < 46 < 45 < 46 < 44 < 44 < 44 < 42 < 43 09/24/20 - 09/30/20 < 35 < 35 < 36 < 34 < 25 < 41 < 42 < 43 < 42 09/30/20 - 10/07/20 < 43 < 44 < 42 < 35 < 41 < 36 < 36 < 16 < 36 10/07/20 - 10/15/20 < 42 < 42 < 42 < 42 < 22 < 59 < 59 < 59 < 28 10/15/20 - 10/22/20 < 30 < 30 < 30 < 28 < 13 < 65 < 65 < 35 < 66 10/22/20 - 10/29/20 < 28 < 65 < 65 < 28 < 65 < 28 < 29 < 11 < 29 10/29/20 - 11/04/20 < 66 < 26 < 63 < 64 < 67 < 29 < 29 < 29 < 29 11/04/20 - 11/12/20 < 45 < 31 < 45 < 44 < 45 < 42 < 42 < 42 < 42 11/12/20 - 11/19/20 < 23 < 47 < 47 < 41 < 46 < 43 < 43 < 19 < 42 11/19/20 - 11/25/20 < 68 < 65 < 67 < 26 < 67 < 67 < 67 < 67 < 29 11/25/20 - 12/02/20 < 51 < 49 < 50 < 44 < 51 < 46 < 23 < 45 < 46 12/02/20 - 12/10/20 < 54 < 23 < 55 < 53 < 54 < 43 < 42 < 42 < 42 12/10/20 - 12/17/20 < 25 < 50 < 51 < 47 < 51 < 43 < 44 < 42 < 44 12/17/20 - 12/23/20 < 49 < 48 < 48 < 54 < 49 < 56 < 56 < 53 < 29 12/23/20 - 12/30/20 < 26 < 55 (1) < 55 < 58 < 58 < 56 < 54 < 57 MEAN - - - - - - - - -

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

Table C-VII.1 CONCENTRATIONS OF I-131 IN MILK SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION CONTROL FARM PERIOD L-42 01/02/20 < 0.6 02/06/20 < 0.7 03/04/20 < 0.9 04/01/20 < 0.5 05/01/20 < 0.7 05/06/20 < 0.9 05/21/20 < 0.9 06/03/20 < 0.9 06/18/20 < 0.9 07/01/20 < 0.7 07/16/20 < 0.9 07/29/20 < 0.7 08/13/20 < 0.9 08/27/20 < 0.9 09/10/20 < 0.9 09/24/20 < 0.9 10/07/20 < 0.8 10/22/20 < 0.8 11/04/20 < 0.9 12/05/20 (1)

MEAN -

(1) SEE PROGRAM EXCEPTIONS SECTION FOR EXPLANATION C-12

Table C-VII.2 CONCENTRATIONS OF GAMMA EMITTERS IN MILK SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-42 01/02/20 < 8 < 8 < 18 < 8 < 17 < 8 < 14 < 9 < 8 < 30 < 7 02/06/20 < 7 < 7 < 11 < 7 < 15 < 6 < 10 < 7 < 6 < 22 < 10 03/04/20 < 8 < 7 < 19 < 8 < 17 < 8 < 13 < 10 < 9 < 38 < 11 04/01/20 < 4 < 4 < 9 < 5 < 10 < 5 < 8 < 5 < 5 < 18 < 6 05/01/20 < 5 < 7 < 17 < 8 < 13 < 6 < 13 < 8 < 8 < 30 < 10 05/06/20 < 8 < 8 < 17 < 11 < 17 < 9 < 16 < 8 < 9 < 33 < 12 05/21/20 < 7 < 8 < 22 < 6 < 18 < 8 < 14 < 7 < 8 < 36 < 12 06/03/20 < 8 < 7 < 18 < 9 < 20 < 9 < 11 < 9 < 8 < 33 < 13 06/18/20 < 8 < 8 < 20 < 8 < 20 < 8 < 12 < 9 < 8 < 33 < 9 07/01/20 < 6 < 6 < 14 < 11 < 13 < 7 < 12 < 7 < 6 < 25 < 7 07/16/20 < 7 < 10 < 15 < 8 < 20 < 9 < 13 < 10 < 8 < 35 < 8 07/29/20 < 7 < 9 < 13 < 10 < 17 < 8 < 16 < 10 < 8 < 39 < 10 08/13/20 < 8 < 7 < 16 < 10 < 19 < 9 < 15 < 8 < 7 < 43 < 10 C-13 08/27/20 < 6 < 9 < 21 < 6 < 19 < 7 < 15 < 8 < 7 < 35 < 9 09/10/20 < 8 < 8 < 12 < 7 < 15 < 8 < 12 < 8 < 7 < 25 < 11 09/24/20 < 9 < 8 < 21 < 7 < 22 < 8 < 14 < 10 < 8 < 38 < 12 10/07/20 < 9 < 9 < 16 < 10 < 17 < 9 < 15 < 9 < 10 < 34 < 11 10/22/20 < 8 < 8 < 19 < 8 < 21 < 8 < 13 < 10 < 9 < 30 < 11 11/04/20 < 5 < 6 < 11 < 6 < 13 < 6 < 10 < 7 < 6 < 26 < 8 12/05/20 (1)

MEAN - - - - - - - - - - -

(1) SEE PROGRAM EXCEPTIONS SECTION FOR EXPLANATION

Table C-VIII.1 CONCENTRATIONS OF GAMMA EMITTERS IN FOOD PRODUCT SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-QUAD 1 Sweet Potatoes 09/02/20 < 26 < 26 < 66 < 27 < 68 < 26 < 51 < 49 < 32 < 28 < 141 < 42 Sweet Potato Leaves 09/02/20 < 30 < 26 < 54 < 26 < 66 < 32 < 40 < 56 < 34 < 32 < 128 < 24 MEAN - - - - - - - - - - - -

L-QUAD 2 Red Cabbage 07/16/20 < 31 < 33 < 81 < 48 < 68 < 43 < 72 < 44 < 39 < 43 < 136 < 49 Green Cabbage 07/16/20 < 41 < 37 < 76 < 42 < 61 < 37 < 71 < 57 < 40 < 41 < 154 < 57 Horseradish 07/23/20 < 43 < 30 < 68 < 39 < 81 < 37 < 58 < 57 < 56 < 55 < 163 < 40 Horseradish Roots 07/23/20 < 41 < 38 < 96 < 40 < 69 < 39 < 69 < 52 < 45 < 38 < 152 < 36 MEAN - - - - - - - - - - - -

L-QUAD 3 C-14 Beet Greens 07/29/20 < 33 < 35 < 65 < 27 < 85 < 30 < 70 < 47 < 32 < 35 < 146 < 43 Red Beets 07/29/20 < 33 < 37 < 82 < 34 < 68 < 33 < 59 < 44 < 39 < 34 < 147 < 52 Potatoes 07/29/20 < 17 < 16 < 45 < 19 < 39 < 17 < 32 < 23 < 20 < 16 < 68 < 23 Red Beets 07/29/20 < 8 < 8 < 21 < 8 < 17 < 8 < 15 < 33 < 8 < 8 < 68 < 20 MEAN - - - - - - - - - - - -

L-QUAD 4 Cabbage 07/01/20 < 25 < 24 < 51 < 30 < 53 < 25 < 46 < 39 < 28 < 27 < 119 < 37 Onions 07/01/20 < 29 < 34 < 63 < 30 < 67 < 33 < 46 < 52 < 29 < 30 < 154 < 47 MEAN - - - - - - - - - - - -

Table C-VIII.2 CONCENTRATIONS OF GAMMA EMITTERS IN VEGETATION SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY 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 L-VEG C Mayapple 05/21/20 < 23 < 21 < 39 < 23 < 50 < 21 < 35 < 31 < 22 < 24 < 103 < 34 Red Clover 05/21/20 < 25 < 26 < 58 < 29 < 55 < 28 < 44 < 40 < 30 < 29 < 116 < 32 Catalpa Tree Leaves 06/18/20 < 33 < 36 < 70 < 38 < 79 < 40 < 59 < 54 < 37 < 34 < 154 < 48 Red Clover 06/18/20 < 37 < 33 < 79 < 43 < 96 < 31 < 70 < 58 < 39 < 45 < 187 < 50 Red Clover 07/16/20 < 16 < 16 < 37 < 18 < 37 < 18 < 30 < 24 < 19 < 17 < 70 < 18 Catalpa Tree Leaves 07/16/20 < 21 < 20 < 40 < 20 < 45 < 20 < 33 < 28 < 22 < 22 < 84 < 25 Collard Greens 07/29/20 < 26 < 36 < 80 < 40 < 68 < 37 < 60 < 45 < 39 < 33 < 157 < 39 Cabbage 07/29/20 < 40 < 40 < 96 < 44 < 72 < 41 < 76 < 56 < 46 < 38 < 161 < 27 Swiss/Green Chards 07/29/20 < 40 < 34 < 84 < 37 < 88 < 31 < 56 < 50 < 38 < 40 < 145 < 46 Dandelion 08/20/20 < 26 < 28 < 53 < 28 < 53 < 26 < 44 < 35 < 26 < 26 < 110 < 30 Mayapple 08/20/20 < 36 < 37 < 68 < 38 < 77 < 36 < 59 < 51 < 40 < 37 < 160 < 45 Milkweed 08/20/20 < 23 < 21 < 45 < 23 < 50 < 23 < 35 < 33 < 23 < 23 < 98 < 23 Cabbage 08/27/20 < 48 < 29 < 72 < 60 < 112 < 50 < 62 < 59 < 51 < 41 < 179 < 39 Tomatoes 09/02/20 < 19 < 24 < 64 < 32 < 36 < 24 < 43 < 41 < 33 < 22 < 130 < 38 Milkweed 09/17/20 < 38 < 32 < 65 < 37 < 89 < 38 < 68 < 56 < 37 < 34 < 161 < 52 Dandelion 09/17/20 < 47 < 47 < 108 < 48 < 118 < 59 < 74 < 57 < 55 < 54 < 250 < 80 White Snakeroot 09/17/20 < 33 < 31 < 61 < 31 < 62 < 27 < 47 < 44 < 33 < 31 < 159 < 42 Potatoes 09/30/20 < 24 < 39 < 66 < 30 < 80 < 38 < 60 < 45 < 24 < 33 < 125 < 32 Velvet Leaves 10/15/20 < 18 < 17 < 36 < 18 < 37 < 19 < 33 < 29 < 18 < 18 < 84 < 27 Dandelion 10/15/20 < 21 < 19 < 40 < 22 < 43 < 19 < 32 < 27 < 21 < 20 < 84 < 26 MEAN - - - - - - - - - - - -

C-15 L-ESE-1 Red Clover 05/21/20 < 20 < 23 < 50 < 24 < 52 < 23 < 42 < 34 < 29 < 24 < 106 < 28 Dandelion 05/21/20 < 29 < 26 < 58 < 29 < 62 < 30 < 54 < 48 < 33 < 29 < 138 < 39 Red Clover 06/18/20 < 37 < 43 < 84 < 44 < 86 < 38 < 64 < 57 < 44 < 39 < 174 < 45 Dandelion 06/18/20 < 32 < 29 < 76 < 33 < 70 < 35 < 60 < 52 < 38 < 34 < 148 < 47 Soy Leaves 07/16/20 < 21 < 21 < 42 < 24 < 45 < 21 < 36 < 33 < 22 < 23 < 95 < 30 Red Clover 07/16/20 < 34 < 33 < 84 < 34 < 70 < 41 < 60 < 57 < 41 < 41 < 164 < 50 Red Clover 08/20/20 < 19 < 18 < 41 < 20 < 41 < 19 < 30 < 24 < 20 < 19 < 74 < 25 Dandelion 08/20/20 < 16 < 15 < 32 < 18 < 35 < 14 < 26 < 20 < 16 < 16 < 62 < 19 Soy Leaves 09/17/20 < 36 < 37 < 82 < 38 < 70 < 36 < 67 < 57 < 42 < 41 < 176 < 44 Dandelion 09/17/20 < 40 < 41 < 68 < 38 < 83 < 45 < 61 < 53 < 34 < 44 < 164 < 63 Clover 10/15/20 < 18 < 20 < 38 < 21 < 40 < 21 < 33 < 29 < 20 < 20 < 91 < 27 Dandelion 10/15/20 < 36 < 23 < 79 < 36 < 77 < 35 < 52 < 49 < 38 < 30 < 137 < 43 MEAN - - - - - - - - - - - -

L-ESE-2 Red Clover 05/21/20 < 24 < 22 < 43 < 30 < 58 < 26 < 41 < 37 < 31 < 26 < 123 < 45 Dandelion 05/21/20 < 25 < 26 < 56 < 27 < 58 < 26 < 42 < 41 < 27 < 27 < 120 < 40 Dock Plant 05/21/20 < 33 < 34 < 64 < 36 < 64 < 32 < 44 < 46 < 30 < 27 < 120 < 39 Red Clover 06/18/20 < 48 < 38 < 90 < 53 < 95 < 39 < 79 < 54 < 55 < 52 < 163 < 27 Dandelion 06/18/20 < 37 < 37 < 66 < 36 < 68 < 42 < 69 < 57 < 40 < 40 < 171 < 47 Broadleaved Plantain 07/16/20 < 17 < 17 < 32 < 19 < 31 < 16 < 32 < 24 < 19 < 18 < 73 < 25 Dandelion 07/16/20 < 19 < 17 < 37 < 18 < 40 < 19 < 32 < 26 < 21 < 19 < 77 < 21 Dandelion 08/20/20 < 14 < 13 < 30 < 15 < 28 < 13 < 24 < 19 < 15 < 14 < 59 < 17 Plantage 08/20/20 < 14 < 14 < 31 < 15 < 32 < 15 < 24 < 21 < 16 < 16 < 64 < 18 Soy Leaved 08/20/20 < 22 < 21 < 43 < 21 < 44 < 22 < 34 < 29 < 22 < 20 < 84 < 25 Dandelion 09/17/20 < 48 < 38 < 85 < 41 < 87 < 48 < 61 < 55 < 52 < 45 < 161 < 54 Clover 09/17/20 < 39 < 38 < 84 < 41 < 87 < 48 < 62 < 56 < 47 < 49 < 166 < 57 Dandelion 10/15/20 < 37 < 42 < 95 < 48 < 96 < 43 < 68 < 53 < 44 < 44 < 191 < 47 Clover 10/15/20 < 34 < 33 < 60 < 41 < 74 < 34 < 57 < 54 < 37 < 32 < 154 < 48 MEAN - - - - - - - - - - - -

Table C-IX.1 QUARTERLY DLR RESULTS FOR LASALLE COUNTY STATION, 2020 Annual Location Annual 2020 Normalized Net Dose, M QX Normalized Facility Qtrly BQ + BA + Facility Location (mrem/std. Qtr.) Annual Dose, BA(1) Dose, Baseline, MDDQ MDDA(2) Dose, FA MA (mrem/yr) FA >10 BQ (mrem) (mrem) 1 2 3 4 mrem L-01 13.3 22.0 9.8 16.4 20.8 21.8 68.8 53.1 87.3 ND No L-03 11.9 20.6 8.9 15.9 20.4 20.2 65.4 45.3 79.5 ND No L-04 12 20.7 8.8 15.8 19.5 21.4 65.5 45.6 79.8 ND No L-05 11.7 20.4 8.2 15.1 20.6 20.8 64.7 46.8 81.0 ND No L-06 13.2 21.9 9.0 16.4 21.0 21.6 68.0 53.0 87.2 ND No L-07 12.9 21.6 8.3 15.9 21.5 21.4 67.1 51.5 85.7 ND No L-08 12.5 21.2 8.3 15.4 20.0 20.2 63.9 50.1 84.3 ND No L-10 10 18.7 6.6 13.1 17.9 20.0 57.6 39.8 74.0 ND No L-101 13.3 22.0 9.9 16.7 22.3 22.4 71.3 50.4 84.6 ND No L-102 14.9 23.6 10.6 17.6 22.6 23.5 74.4 59.5 93.7 ND No L-103 12.3 21.0 9.2 16.1 21.3 20.6 67.2 49.2 83.4 ND No L-104 11.6 20.3 8.2 14.9 19.4 20.7 63.3 46.3 80.5 ND No L-105 13.3 22.0 9.6 15.6 21.1 22.0 68.2 53.2 87.4 ND No L-106 12.3 21.0 10.0 15.4 20.7 20.7 66.8 49.2 83.4 ND No L-107 12.8 21.5 9.5 16.9 21.8 22.7 70.9 51.2 85.4 ND No L-108 11.1 19.8 10.1 15.8 21.4 21.3 68.5 44.3 78.5 ND No L-109 12.9 21.6 8.8 14.8 21.7 21.1 66.4 51.6 85.8 ND No L-110 12.4 21.1 9.1 16.7 20.1 21.3 67.2 49.7 83.9 ND No L-111B 13.1 21.8 9.0 16.5 20.3 20.9 66.8 52.3 86.5 ND No L-112 12.4 21.1 8.8 15.4 21.1 21.2 66.4 49.6 83.8 ND No L-113A 13.8 22.5 11.6 17.7 22.4 22.1 73.8 55.2 89.4 ND No L-114 13.1 21.8 9.0 16.1 22.3 20.7 68.1 50.0 84.2 ND No L-115 11.2 19.9 8.3 14.8 22.3 20.4 65.8 44.8 79.0 ND No L-116 11.2 19.9 9.0 14.6 18.7 21.8 64.2 44.8 79.0 ND No L-11A 10.3 19.0 7.5 15.4 20.6 19.4 62.9 41.2 75.4 ND No L-201 11 19.7 5.9 12.0 17.1 18.0 52.9 43.8 78.0 ND No L-202 10.2 18.9 7.2 12.6 19.0 18.1 57.0 40.9 75.1 ND No L-203 12.8 21.5 8.8 15.4 21.6 20.9 66.7 51.1 85.3 ND No L-204 13.3 22.0 9.9 16.4 22.5 22.1 71.0 50.7 84.9 ND No L-205A 12.2 20.9 9.2 16.0 20.7 21.1 67.1 48.8 83.0 ND No L-205B 12 20.7 9.3 15.4 20.3 20.6 65.6 45.7 79.9 ND No L-206 12.9 21.6 9.1 17.1 21.3 20.3 67.7 51.6 85.8 ND No L-207 12.1 20.8 8.9 17.0 20.7 20.8 67.4 48.5 82.7 ND No L-208 13.1 21.8 9.9 17.5 23.0 22.6 73.1 44.6 78.8 ND No L-209 12.4 21.1 10.0 16.7 (3) 20.3 46.9 47.2 81.4 ND No L-210 13.7 22.4 10.4 20.2 22.2 23.5 76.2 51.9 86.1 ND No L-211 13.5 22.2 8.7 16.7 22.2 21.8 69.4 54.1 88.3 ND No L-212 13.3 22.0 9.6 17.1 21.3 21.8 69.7 50.5 84.7 ND No L-213 11.5 20.2 8.6 15.1 19.4 20.7 63.8 41.6 75.8 ND No L-214 11.9 20.6 9.0 15.5 20.8 21.2 66.5 47.6 81.8 ND No L-215 13.6 22.3 10.3 17.1 21.7 22.0 71.1 54.4 88.6 ND No L-216 13.4 22.1 9.3 16.4 20.8 22.2 68.7 53.5 87.7 ND No (1)

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

Minimum differential dose (MDD A): The smallest amount of facility related dose at each monitored location annually above the baseline background dose that can be reliably detected by an environmental dosimetry system (3) SEE PROGRAM EXCEPTIONS SECTION FOR EXPLANATION C-16

FIGURE C-1 Surface Water - Gross Beta - Stations L-21 (C) and L-40 Collected in the Vicinity of LSCS, 2005 - 2020 L-21 (C) Illinois River at Seneca 14.0 12.0 10.0 8.0 pCi/L 6.0 4.0 2.0 0.0 01-27-05 05-21-10 09-12-15 01-03-21 L-40 Illinois River Downstream 12.0 10.0 8.0 pCi/L 6.0 4.0 2.0 0.0 01-27-05 05-21-10 09-12-15 01-03-21 C-17

FIGURE C-2 Surface Water - Tritium - Stations L-21 (C) and L-40 Collected in the Vicinity of LSCS, 2005 - 2020 L-21 Illinois River at Seneca 2000 1600 1200 pCi/L 800 400 0

03-31-05 03-09-09 02-15-13 01-24-17 01-02-21 L-40 Illinois River Downstream 2000 1600 1200 pCi/L 800 400 0

03-31-05 03-09-09 02-15-13 01-24-17 01-02-21 C-18

FIGURE C-3 Air Particulate - Gross Beta - Stations L-01 and L-03 Collected in the Vicinity of LSCS, 2005 - 2020 L-01 Nearsite No. 1 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-06-05 01-05-09 01-04-13 01-03-17 01-02-21 L-03 Onsite No. 3 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-06-05 01-05-09 01-04-13 01-03-17 01-02-21 C-19

FIGURE C-4 Air Particulate - Gross Beta - Stations L-05 and L-06 Collected in the Vicinity of LSCS, 2005 - 2020 L-05 Onsite No. 5 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-06-05 01-05-09 01-04-13 01-03-17 01-02-21 L-06 Nearsite No. 6 70.0 60.0 50.0 10E-03 pCi/m3 40.0 30.0 20.0 10.0 0.0 01-06-05 01-05-09 01-04-13 01-03-17 01-02-21 C-20

FIGURE C-5 Air Particulate - Gross Beta - Station L-10 (C)

Collected in the Vicinity of LSCS, 2005 - 2020 L-10 (C) Streator 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 01-06-05 01-05-09 01-04-13 01-03-17 01-02-21 C-21

FIGURE C-6 Air Particulate - Gross Beta - Stations L-04 and L-07 Collected in the Vicinity of LSCS, 2005 - 2020 L-04 Rte. 170 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-07-05 05-22-09 04-06-13 02-19-17 01-04-21 L-07 Seneca 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-07-05 05-22-09 04-06-13 02-19-17 01-04-21 C-22

FIGURE C-7 Air Particulate - Gross Beta - Stations L-08 and L-11 Collected in the Vicinity of LSCS, 2005 - 2020 L-08 Marseilles 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-07-05 05-22-09 04-06-13 02-19-17 01-04-21 L-11 Ransom (1) 60.0 50.0 40.0 10E-03 pCi/m3 30.0 20.0 10.0 0.0 07-07-05 01-14-09 07-24-12 02-01-16 (1) Air monitoring station L-11 was retired on 01/21/16 C-23

FIGURE C-8 Air Particulate - Gross Beta - Station L-11A Collected in the Vicinity of LSCS, 2016 - 2020 L-11A Ransom (1) 40.0 30.0 10E-03 pCi/m3 20.0 10.0 0.0 01-07-16 09-05-17 05-05-19 01-01-21 (1) Air monitoring station L-11A was placed in service on 01/14/16 C-24

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)

D-1

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)

D-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 - 0.898 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)

D-3

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)

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APPENDIX E EFFLUENT DATA

Intentionally left blank TABLE OF CONTENTS Introduction .......................................................................................................................... 1 Summary .............................................................................................................................. 2 1.0. Effluents ................................................................................................................ 3 1.1. Gaseous Effluents to the Atmosphere ....................................................... 3 1.2. Liquids Released to Illinois River ............................................................... 3 2.0. Solid Radioactive Waste ....................................................................................... 3 3.0. Dose To Man......................................................................................................... 3 3.1. Gaseous Effluent Pathways ....................................................................... 3 3.1.1. Noble Gases ................................................................................ 3 3.1.1.1. Gamma Dose Rates ...................................................... 3 3.1.1.2. Beta Air and Skin Dose Rates ....................................... 4 3.1.2. Radioactive Iodine........................................................................ 4 3.1.2.1. Dose to Thyroid.............................................................. 4 3.2. Liquid Effluent Pathways ............................................................................ 4 3.3. Assessment of Dose to Member of Public ................................................. 5 4.0. Site Meteorology ................................................................................................... 5 Appendix E-1 Data Tables and Figures.................................................................. E-1.1 Station Releases Table 1.1-1 Gaseous Effluents Summation of all Releases ....................... E-1.2 Table 1.2-1 Summation of all Liquid Releases ........................................... E-1.3 Table 2.1-1 Solid Radwaste Annual Report (2017) .................................... E-1.4 Table 3.1-1 Maximum Doses Resulting from Gaseous Releases and Compliance Status.............................................................. E-1.5 Table 3.2-1 Maximum Doses Resulting from Liquid Releases and Compliance Status.............................................................. E-1.6 Table 3.3-1 Maximum Doses Resulting from Releases and Compliance Status .............................................................. E-1.7 Table 3.4-1 Maximum Doses Resulting from Airborne Releases Based On Concurrent Meteorological Data ................................. E-1.8 E-1

Introduction LaSalle County Station, a two-unit BWR, is located near Marseilles, Illinois in LaSalle County, 3.5 miles south of the Illinois River. Both units are rated at 3546 MWt. Unit 1 loaded fuel in March 1982. Unit 2 loaded fuel in late December 1983. The Station is designed to keep releases to the environment at levels below those specified in the regulations.

Liquid effluents, although no longer batch released from LaSalle County Station, were designed to be released to the Illinois River in controlled batches after radioassay of each batch. Gaseous effluents are released to the atmosphere after delay allowing time for short-lived (noble) gases to decay. Releases to the atmosphere are sampled and analyzed on a routine basis. The gaseous effluent samples are analyzed for particulate, iodine, noble gas, and tritium activity. The particulate and iodine sample results are obtained from continuously collected composite samples. The noble gas and tritium sample results are obtained from routine grab samples. The results of effluent analyses are summarized on a monthly basis and reported to the Nuclear Regulatory Commission as required per Technical Specifications. Airborne concentrations of noble gases, tritium, I-131, and particulate radioactivity in offsite areas are calculated using effluent and meteorological data.

Environmental monitoring is conducted by sampling at indicator and control (background) locations in the vicinity of LaSalle County Station to measure changes in radiation or radioactivity levels that may be attributable to station operations. If significant changes attributable to LaSalle County Station are measured, these changes are correlated with effluent releases. External gamma radiation exposure from noble gases and internal dose from I-131 in milk are the critical pathways at this site; however, an environmental monitoring program is conducted which also includes these and many other pathways which are less significant in terms of radiation protection.

E-2

Summary Gaseous effluents for the period contributed to only a small fraction of the LaSalle County Station Radiological Effluent Controls Limits. Liquid effluents had no contribution to offsite dose, as no liquid batch radioactive discharges were conducted.

Calculations of environmental concentrations based on effluent, Illinois River flow, and meteorological data for the period indicate that consumption by the public of radionuclides attributable to LaSalle County Station does not exceed regulatory limits.

Radiation exposure from radionuclides released to the atmosphere represented the critical pathway for the period with a maximum individual total dose estimated to be 1.61E-03 mrem for the year, where a shielding factor of 0.7 and an occupancy factor of 0.95 are assumed for the nearest resident. The assessment of radiation doses is performed in accordance with the Offsite Dose Calculation Manual (ODCM),

specifically, a comparison of preoperational studies with operational controls or with previous environmental surveillance reports and an assessment of the observed impacts of the plant operation on the environment. Control locations are basis for preoperational data. The results of analysis confirm that the station is operating in compliance with 10 CFR 50 Appendix I, 10 CFR 20 and 40 CFR 190.

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1.0 Effluents 1.1 Gaseous Effluents to the Atmosphere Measured concentrations of noble gases, radioiodine, and particulate radioactivity released to the atmosphere during the year, are listed in Table 1.1-1. A total of 2.50E+02 curies of fission and activation gases were released with an average release rate of 7.89E+00 µCi/sec.

A total of 8.79E-03 curies of I-131 were released during the year with an average release rate of 2.79E-04 µCi/sec.

A total of 2.63E-04 curies of beta-gamma emitters were released as airborne particulate matter with an average release rate of 8.30E-06

µCi/sec. Alpha-emitting radionuclides were below the lower limit of detection (LLD). Carbon-14 released in 2020 was calculated separately with a total of 3.50E+01 curies released.

A total of 8.63E+01 curies of tritium were released with an average release rate of 1.11E+00 µCi/sec.

1.2 Liquids Released to Illinois River There were no liquid batch releases in 2020. Continuous release path activity was below applicable Lower Limits of Detection.

2.0 Solid Radioactive Waste Solid radioactive wastes were shipped by truck to a disposal facility or to a waste processor. For further detail, refer the LaSalle 2020 Annual Radioactive Effluent Release Report (ARERR). This report was submitted to the USNRC by the required date of May 1st, 2021.

3.0 Dose To Man 3.1 Gaseous Effluent Pathways Table 3.1-1 summarizes the doses resulting from releases of airborne radioactivity via the different exposure pathways.

3.1.1 Noble Gases 3.1.1.1 Gamma Dose Rates Unit 1 and Unit 2 gaseous releases at LaSalle County Station are reported as Unit 1 releases due to a single station vent stack (SVS) release point. Offsite Gamma air and whole body dose rates are shown in Table 3.1-1 and were calculated based on measured release rates, isotopic composition of the noble gases and average meteorological data for the period. Doses based on concurrent meteorological data are shown in Table 3.4-1. Based on measured effluents and meteorological data, the maximum total body dose to an individual would be 1.61E-03 mrem E-4

(Table 3.1-1) for the year, with an occupancy factor of 0.95 and a shielding factor of 0.7 included. The maximum total body dose based on measured effluents and concurrent meteorological data would be 1.11E-02 mrem (Table 3.4-1).

The maximum gamma air dose was 2.42E-03 mrad from Table 3.1-1, and the maximum gamma air dose from concurrent meteorological data was 2.36E-04 mrad (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 "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 (from beta and gamma radiation) for the year was 2.73E-03 mrem from Table 3.1-1, and the skin dose from concurrent meteorological data was 4.00E-04 mrem (Table 3.4-1).

The maximum offsite beta dose for the year was 1.37E-04 mrad from Table 3.1-1, and the maximum offsite beta dose from concurrent meteorological data was 1.03E-04 mrad (Table 3.4-1).

3.1.2 Radioactive Iodine The human thyroid exhibits a significant capacity to concentrate ingested or inhaled iodine. The radioiodine, I-131, released during routing operation of the plant, may be made available to man resulting in a dose to the thyroid. The principal pathway of interest for this radionuclide is ingestion of radioiodine in milk.

3.1.2.1 Dose to Thyroid The hypothetical thyroid dose to a maximum exposed individual living near the station via ingestion of milk was calculated. The radionuclide considered was I-131 and the source of milk was taken to be the nearest dairy farm with the cows pastured from May through October. The maximum thyroid dose due to I-131 was 4.88E-02 mrem for the year.

3.2 Liquid Effluent Pathways The three principal pathways through the aquatic environment for potential E-5

doses to man from liquid waste are ingestion of potable water, eating aquatic foods, and exposure while on the shoreline. Not all of these pathways are significant or applicable at a given time but a reasonable approximation of the dose can be made by adjusting the dose formula for season of the year or type and degree of use of the aquatic environment.

NRC developed equations* were used to calculate the doses to the whole body, lower gastro-intestinal tracts, thyroid, bone and skin; specific parameters for use in the equations are given in the Offsite Dose Calculation Manual. The maximum whole body dose was 0.00E+00 mrem and organ dose was 0.00E+00 for the year mrem (Table 3.2-1).

3.3 Assessment of Dose to Member of Public During the period January to December 2020, LaSalle County Station did not exceed these limits as shown in Table 3.1-1 and Table 3.2-1 (based on annual average meteorological data), and as shown in Table 3.3-1:

• The Radiological Effluent Technical Standards (RETS) limits on dose or dose commitment to an individual due to radioactive materials in liquid effluents from each reactor unit (1.5 mrem to the whole body or 5 mrem to any organ during any calendar year; 3 mrem to the whole body or 10 mrem to any organ during the calendar year).

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

• The RETS limits on dose to a member of the public due to iodine-131, iodine-133, tritium and radionuclides in particulate form with half-lives greater than eight days in gaseous effluents released from each reactor unit (7.5 mrem to any organ during any calendar quarter; 15 mrem to any organ during any calendar year).

• The 10 CFR 20 limit on Total Effective Dose Equivalent to individual members of the public (100 mrem).

4.0 Site Meteorology A summary of the site meteorological measurements taken during each calendar quarter of the year is given in Appendix F. The data are presented as cumulative joint frequency distributions of the wind direction for the 375 level and wind speed class by atmospheric stability class determined from the temperature difference between the 375 and 33 levels. Data recovery for these measurements was 99.8% during 2020.

• Nuclear Regulatory Commission, Regulatory Guide 1.109 (Rev. 1)

E-6

APPENDIX E-1 DATA TABLES AND FIGURES

Intentionally left blank Table 1.1-1 LASALLE COUNTY NUCLEAR POWER STATION EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT (2020)

UNIT 1 AND UNIT 2 DOCKET NUMBERS 50-373 AND 50-374 GASEOUS EFFLUENTS SUMMATION OF ALL RELEASES Est. Total A. Fission & Activation Gases Unit Quarter 1 Quarter 2 Quarter 3 Quarter4 Error %

1. Total Release Ci 1.18E+02 7.58E+01 3.28E+01 2.30E+01 2.50E+01

2. Average release rate for the period µCi/sec 1.50E+01 9.62E+00 4.16E+00 2.92E+00

3. Percent of ODCM limit  % * * *

• B. Iodine

1. Total Iodine - 131 Ci 2.59E-03 2.12E-03 2.30E-03 1.78E-03 1.50E+01

2. Average release rate for the period µCi/sec 3.28E-04 2.69E-04 2.92E-04 2.26E-04

3. Percent of ODCM limit  % * * *

• C. Particulates

1. Particulates with half-lives > 8 days Ci 6.86E-05 1.52E-04 4.20E-05 <LLD 3.50E+01

2. Average release rate for the period µCi/sec 8.73E-06 1.93E-05 5.28E-06 N/A

3. Percent of ODCM limit  % * * *

• D. Tritium

1. Total Release Ci 1.36E+01 1.90E+01 1.69E+01 3.68E+01 1.50E+01

2. Average release rate for the period µCi/sec 1.73E+00 2.41E+00 2.14E+00 4.67E+00

3. Percent of ODCM limit  % * * *

• E. Gross Alpha

1. Total Release Ci <LLD <LLD <LLD <LLD N/A

2. Average release rate for the period µCi/sec <LLD <LLD <LLD <LLD

3. Percent of ODCM limit  % * * *

• F. Carbon-14

1. Total Release Ci 8.30E+00 8.79E+00 9.02E+00 8.93E+00

2. Average release rate for the period µCi/sec 1.06E+00 1.11E+00 1.14E+00 1.13E+00

3. Percent of ODCM limit  % * * * *

"*" This information is contained in the Radiological Impact on Man section of the report.

"<" Indicates activity of sample is less than LLD given in µCi/ml The LaSalle County Nuclear Power Station maximum expected annual dose from Carbon-14 has been calculated using the maximum gross thermal capacity at full power operation. The resultant bounding doses are based upon site specific assumptions of source term.

E-1-1

Table 1.2-1 LASALLE COUNTY NUCLEAR POWER STATION EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT (2020)

LIQUID RELEASES UNIT 1 AND UNIT 2 SUMMATION OF ALL LIQUID RELEASES Est. Total A. Fission & Activation Products Unit Quarter 1 Quarter 2 Quarter 3 Quarter4 Error %

1. Total Release (not including tritium, gases Ci <LLD <LLD <LLD <LLD N/A

& alpha)

2. Average diluted concentration during

µCi/mL <LLD <LLD <LLD <LLD period

3. Percent of applicable limit  % * * *

• B. Tritium

1. Total Release Ci <LLD <LLD <LLD <LLD N/A

2. Average diluted concentration during

µCi/mL <LLD <LLD <LLD <LLD period

3. Percent of applicable limit  % * * *

• C. Dissolved & Entrained Gases

1. Total Release Ci <LLD <LLD <LLD <LLD N/A

2. Average diluted concentration during

µCi/mL <LLD <LLD <LLD <LLD period

3. Percent of applicable limit  % * * *

• D. Gross Alpha Activity

1. Total Release Ci <LLD <LLD <LLD <LLD N/A

2. Average release rate for the period µCi/mL <LLD <LLD <LLD <LLD

3. Percent of ODCM limit  % * * *

• E. Volume of Waste Released (prior to Liters 0.00E+00 0.00E+00 0.00E+00 0.00E+00 dilution)

F. Volume of Dilution Water Used During Liters 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Period

"*" This information is contained in the Radiological Impact on Man section of the report.

"<" Indicates activity of sample is less than LLD given in µCi/ml E-1-2

Table 2.1-1 LASALLE COUNTY NUCLEAR POWER STATION SOLID WASTE ANNUAL REPORT (2020)

Table 2.1-1 deliberately deleted. For solid waste disposal detail, refer to the LaSalle County Station 2020 Annual Radiological Effluent Release Report (ARERR).

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Table 3.1-1 LASALLE COUNTY NUCLEAR POWER STATION EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT (2020)

RADIOLOGICAL IMPACT ON MAN MAXIMUM DOSES RESULTING FROM GASEOUS RELEASES AND COMPLIANCE STATUS All Age Quarterly 1st 2nd 3rd 4th Annual Units Annual Groups Limit Quarter Quarter Quarter Quarter Limit Gamma Air 5.00E+00 mRad 1.27E-03 7.88E-04 1.24E-04 2.36E-04 1.00E+01 2.42E-03

% of Limit  % 2.53E-02 1.58E-02 2.49E-03 4.73E-03  % 2.42E-02 Beta Air 1.00E+01 mRad 6.38E-05 4.17E-05 1.78E-05 1.38E-05 2.00E+01 1.37E-04

% of Limit  % 6.38E-04 4.17E-04 1.78E-04 1.38E-04  % 6.86E-04 NG Total Body 2.50E+00 mRem 8.46E-04 5.26E-04 8.34E-05 1.58E-04 5.00E+00 1.61E-03

% of Limit  % 3.38E-02 2.10E-02 3.34E-03 6.31E-03  % 3.22E-02 E-1-4 NG Skin 7.50E+00 mRem 1.43E-03 8.88E-04 1.47E-04 2.68E-04 1.50E+01 2.73E-03

% of Limit  % 1.90E-02 1.18E-02 1.95E-03 3.57E-03 1.82E-02 NNG Organ 7.50E+00 mRem 1.39E-02 1.19E-02 1.28E-02 1.03E-02 1.50E+01 4.887E-02 Infant Thyroid  % of Limit  % 1.85E-01 1.58E-01 1.71E-01 1.37E-01  % 3.258E-01 The LaSalle County Nuclear Power Station maximum expected annual dose from Carbon-14 has been calculated using the maximum gross thermal capacity at full power operation. The resultant bounding doses are based upon site specific assumptions of source term.

Table 3.2-1 LASALLE COUNTY NUCLEAR POWER STATION EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT (2020)

RADIOLOGICAL IMPACT ON MAN MAXIMUM DOSES RESULTING FROM LIQUID RELEASES AND COMPLIANCE STATUS Infant Quarterly 1st  % of 2nd  % of 3rd  % of 4th  % of Annual  % of Units Receptor Limit Quarter Limit Quarter Limit Quarter Limit Quarter Limit Limit Limit 10CFR50 Appendix I compliance Total Body 1.50E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 3.00E+00 0.00 Organ 5.00E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 1.00E+01 0.00 40CFR141 compliance (nearest public drinking water)

Total Body mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 Organ mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 Child Quarterly 1st  % of 2nd  % of 3rd  % of 4th  % of Annual  % of Units Receptor Limit Quarter Limit Quarter Limit Quarter Limit Quarter Limit Limit Limit 10CFR50 Appendix I compliance Total Body 1.50E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 3.00E+00 0.00 Organ 5.00E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 1.00E+01 0.00 40CFR141 compliance (nearest public drinking water)

Total Body mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 E-1-5 Organ mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 Teenager Quarterly 1st  % of 2nd  % of 3rd  % of 4th  % of Annual  % of Units Receptor Limit Quarter Limit Quarter Limit Quarter Limit Quarter Limit Limit Limit 10CFR50 Appendix I compliance Total Body 1.50E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 3.00E+00 0.00 Organ 5.00E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 1.00E+01 0.00 40CFR141 compliance (nearest public drinking water)

Total Body mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 Organ mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 Adult Quarterly 1st  % of 2nd  % of 3rd  % of 4th  % of Annual  % of Units Receptor Limit Quarter Limit Quarter Limit Quarter Limit Quarter Limit Limit Limit 10CFR50 Appendix I compliance Total Body 1.50E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 3.00E+00 0.00 Organ 5.00E+00 mRem 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 0.00E+00 0.00 1.00E+01 0.00 40CFR141 compliance (nearest public drinking water)

Total Body mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00 Organ mRem 0.00E+00 0.00E+00 0.00E+00 0.00E+00 4.00E+00 0.00

Table 3.3-1 LASALLE COUNTY NUCLEAR POWER STATION EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT (2020)

RADIOLOGICAL IMPACT ON MAN MAXIMUM DOSES RESULTING FROM RELEASES AND COMPLIANCE STATUS 10CFR20 / 40CFR190 Compliance 1st 2nd 3rd 4th  %

Quarter Quarter Quarter Quarter Annual Annual Annual Dose Dose Dose Dose Dose Limit Limit (mRem) (mRem) (mRem) (mRem) (mRem) (mRem/yr)

Unit 1 40CFR190 Compliance U1 DEx 8.30E-02 1.03E-01 9.68E-02 4.37E-02 3.26E-01 25 1.30 10CFR20 Compliance U1 DTot 9.68E-02 1.15E-01 1.10E-01 5.40E-02 3.75E-01 100 0.37 40CFR190 Compliance Bone 6.50E-03 7.13E-03 7.31E-03 7.23E-03 2.82E-02 25 0.11 Liver 1.43E-03 1.56E-03 1.60E-03 1.58E-03 6.18E-03 25 0.02 Thyroid 1.39E-02 1.19E-02 1.28E-02 1.03E-02 4.88E-02 75 0.07 Kidney 1.44E-03 1.57E-03 1.61E-03 1.59E-03 6.20E-03 25 0.02 Lung 1.39E-03 1.53E-03 1.57E-03 1.56E-03 6.04E-03 25 0.02 GI-LLI 1.39E-03 1.53E-03 1.57E-03 1.56E-03 6.05E-03 25 0.02 Unit 2 40CFR190 Compliance U2 DEx 9.80E-02 9.68E-02 9.63E-02 6.94E-02 3.60E-01 25 1.44 10CFR20 Compliance U2 DTot 9.80E-02 9.68E-02 9.63E-02 6.94E-02 3.60E-01 100 0.36 40CFR190 Compliance Bone 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 25 0.00 Liver 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 25 0.00 Thyroid 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 75 0.00 Kidney 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 25 0.00 Lung 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 25 0.00 GI-LLI 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 25 0.00 E-1-6

Table 3.4-1 LASALLE COUNTY NUCLEAR POWER STATION EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT (2020)

RADIOLOGICAL IMPACT ON MAN MAXIMUM DOSES RESULTING FROM AIRBORNE RELEASES BASED ON CONCURRENT METEROLOGICAL DATA Doses Resulting From Airborne Releases The following are the maximum annual calculated cumulative offsite doses resulting from LaSalle County Station airborne releases:

LaSalle County Generating Station:

Sector Dose Maximum Value Affected gamma air (1) 2.360 E-04 mrad East-Northeast beta air (2) 1.030 E-04 mrad East- Northeast whole body (3) 1.110 E-02 mrem East- Northeast skin (4) 4.000 E-04 mrem East- Northeast organ (5) (infant-thyroid) 1.730 E-01 mrem East-Southeast 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 0.32 skin 15.0 mrem 0.00 organ 15.0 mrem 2.85 (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 E-1-7

Intentionally left blank APPENDIX F METEOROLOGICAL DATA

Intentionally left blank LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Extremely Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 3 0 0 4 SSW 0 0 0 0 1 0 1 SW 0 0 0 1 0 0 1 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 4 1 0 6 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: 5 F-1

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Moderately Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 2 0 0 2 SSW 0 0 0 2 2 0 4 SW 0 0 3 9 0 1 13 WSW 0 0 1 0 0 0 1 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 4 13 2 1 20 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: 5 F-2

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Slightly Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 2 0 0 2 SSW 0 0 0 2 2 0 4 SW 0 0 3 9 0 1 13 WSW 0 0 1 0 0 0 1 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 4 13 2 1 20 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: 5 F-3

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Neutral - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 18 54 21 0 0 95 NNE 0 15 63 31 0 0 109 NE 0 9 21 17 0 0 47 ENE 1 3 22 13 0 0 39 E 1 3 17 11 3 0 35 ESE 0 2 7 12 2 1 24 SE 2 5 12 8 3 0 30 SSE 6 8 16 10 2 1 43 S 2 12 13 14 7 0 48 SSW 4 10 12 15 8 1 50 SW 2 11 8 13 1 0 35 WSW 3 19 27 5 1 6 61 W 4 20 43 42 12 3 124 WNW 0 28 53 43 34 1 159 NW 0 18 30 29 2 0 79 NNW 2 20 63 45 15 4 149 Variable 0 0 0 0 0 0 0 Total 29 201 461 329 90 17 1127 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: 5 F-4

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Slightly Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 11 0 0 0 0 13 NNE 0 6 4 0 0 0 10 NE 1 1 13 3 0 0 18 ENE 0 3 21 5 0 0 29 E 2 18 55 9 0 0 84 ESE 1 8 14 12 0 0 35 SE 2 15 9 8 2 0 36 SSE 0 19 8 8 4 0 39 S 3 12 18 25 14 0 72 SSW 5 7 11 32 26 1 82 SW 2 11 13 23 10 1 60 WSW 1 12 27 8 7 1 56 W 1 13 26 16 7 14 77 WNW 2 16 35 15 12 7 87 NW 0 5 17 0 0 0 22 NNW 2 6 4 0 0 0 12 Variable 0 0 0 0 0 0 0 Total 24 163 275 164 82 24 732 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: 5 F-5

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Moderately Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 11 0 0 0 0 13 NNE 0 6 4 0 0 0 10 NE 1 1 13 3 0 0 18 ENE 0 3 21 5 0 0 29 E 2 18 55 9 0 0 84 ESE 1 8 14 12 0 0 35 SE 2 15 9 8 2 0 36 SSE 0 19 8 8 4 0 39 S 3 12 18 25 14 0 72 SSW 5 7 11 32 26 1 82 SW 2 11 13 23 10 1 60 WSW 1 12 27 8 7 1 56 W 1 13 26 16 7 14 77 WNW 2 16 35 15 12 7 87 NW 0 5 17 0 0 0 22 NNW 2 6 4 0 0 0 12 Variable 0 0 0 0 0 0 0 Total 24 163 275 164 82 24 732 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: 5 F-6

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Extremely Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 11 0 0 0 0 13 NNE 0 6 4 0 0 0 10 NE 1 1 13 3 0 0 18 ENE 0 3 21 5 0 0 29 E 2 18 55 9 0 0 84 ESE 1 8 14 12 0 0 35 SE 2 15 9 8 2 0 36 SSE 0 19 8 8 4 0 39 S 3 12 18 25 14 0 72 SSW 5 7 11 32 26 1 82 SW 2 11 13 23 10 1 60 WSW 1 12 27 8 7 1 56 W 1 13 26 16 7 14 77 WNW 2 16 35 15 12 7 87 NW 0 5 17 0 0 0 22 NNW 2 6 4 0 0 0 12 Variable 0 0 0 0 0 0 0 Total 24 163 275 164 82 24 732 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: 5 F-7

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Extremely Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 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 0 0 1 0 0 1 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: 5 F-8

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Moderately Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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: 5 F-9

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Slightly Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 2 1 0 3 SSW 0 0 0 0 0 2 2 SW 0 0 0 3 0 0 3 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 5 1 2 8 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: 5 F-10

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Neutral - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 15 27 41 21 1 106 NNE 1 4 19 45 55 5 129 NE 2 3 9 41 15 0 70 ENE 2 2 9 25 11 0 49 E 0 1 12 21 5 3 42 ESE 0 4 10 12 16 4 46 SE 1 5 5 8 10 2 31 SSE 1 6 6 20 12 5 50 S 2 10 13 18 12 13 68 SSW 1 7 10 8 16 19 61 SW 1 6 16 8 14 7 52 WSW 1 7 23 19 5 9 64 W 3 11 20 42 35 14 125 WNW 1 7 27 21 35 30 121 NW 0 14 63 39 43 15 174 NNW 0 7 23 43 24 18 115 Variable 0 0 0 0 0 0 0 Total 17 109 292 411 329 145 1303 Hours of calm in this stability class: 0 Hours of missing wind measurements in this stability class: 1 Hours of missing stability measurements in all stability classes: 5 F-11

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Slightly Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 3 3 0 6 NNE 1 1 3 1 1 0 7 NE 0 2 3 3 3 0 11 ENE 0 0 2 9 7 0 18 E 0 1 3 27 4 1 36 ESE 0 1 6 23 12 6 48 SE 2 2 9 11 15 3 42 SSE 1 7 12 3 3 6 32 S 0 7 21 14 17 28 87 SSW 2 6 7 15 14 55 99 SW 1 1 11 9 16 32 70 WSW 1 3 5 18 12 9 48 W 3 3 8 26 6 13 59 WNW 1 4 9 17 10 46 87 NW 0 2 20 26 6 4 58 NNW 0 4 5 7 3 0 19 Variable 0 0 0 0 0 0 0 Total 12 44 124 212 132 203 727 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: 5 F-12

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Moderately Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 1 2 1 2 0 7 NNE 0 2 0 0 0 0 2 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 0 6 0 0 7 SE 0 0 4 5 0 0 9 SSE 0 0 0 5 2 0 7 S 0 0 1 4 7 7 19 SSW 0 0 0 1 3 6 10 SW 0 1 9 5 6 1 22 WSW 0 0 2 4 3 1 10 W 0 0 4 3 7 0 14 WNW 0 0 3 4 2 1 10 NW 0 1 6 2 1 0 10 NNW 0 1 1 0 0 0 2 Variable 0 0 0 0 0 0 0 Total 1 7 32 40 33 16 129 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: 5 F-13

LaSalle County Generating Station Period of Record: January - March 2020 Stability Class - Extremely Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 1 S 0 0 0 0 0 1 1 SSW 0 0 0 0 0 0 0 SW 0 1 2 1 0 0 4 WSW 0 0 0 3 0 0 3 W 0 1 0 0 0 0 1 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 4 0 2 10 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: 5 F-14

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Extremely Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 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 1 0 0 1 SSW 0 0 2 0 0 0 2 SW 0 0 1 2 4 0 7 WSW 0 0 0 0 1 0 1 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 4 3 6 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: 3 F-15

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Moderately Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 2 0 0 2 NNE 0 0 0 1 0 0 1 NE 0 0 5 1 0 0 6 ENE 0 0 5 2 0 0 7 E 0 0 3 2 0 0 5 ESE 0 0 1 0 0 0 1 SE 0 0 0 2 1 0 3 SSE 0 0 0 0 3 0 3 S 0 0 0 2 0 0 2 SSW 0 0 0 3 1 0 4 SW 0 0 3 6 1 0 10 WSW 0 0 5 4 5 0 14 W 0 0 4 9 0 0 13 WNW 0 0 0 11 3 0 14 NW 0 0 0 0 0 0 0 NNW 0 0 0 1 1 0 2 Variable 0 0 0 0 0 0 0 Total 0 0 26 46 15 0 87 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 F-16

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Slightly Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 1 1 0 0 2 NNE 0 1 2 0 0 0 3 NE 0 1 7 1 0 0 9 ENE 0 1 4 3 0 0 8 E 0 0 6 5 0 0 11 ESE 0 0 2 3 0 1 6 SE 0 1 7 4 1 0 13 SSE 0 0 5 7 3 0 15 S 0 0 8 2 0 0 10 SSW 0 1 11 3 2 0 17 SW 0 5 8 5 0 1 19 WSW 0 1 8 4 3 0 16 W 0 5 13 7 4 0 29 WNW 0 1 7 11 3 0 22 NW 0 2 2 7 1 0 12 NNW 0 1 3 5 0 0 9 Variable 0 0 0 0 0 0 0 Total 0 20 94 68 17 2 201 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 F-17

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Neutral - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 18 27 2 1 0 49 NNE 0 24 40 11 0 0 75 NE 0 11 45 28 0 0 84 ENE 0 13 16 31 0 0 60 E 0 7 26 21 0 0 54 ESE 0 6 14 16 2 1 39 SE 1 15 27 5 3 3 54 SSE 0 9 18 19 8 1 55 S 2 15 20 9 2 1 49 SSW 2 12 17 7 4 0 42 SW 0 8 19 7 9 1 44 WSW 3 14 16 8 5 1 47 W 0 12 26 11 11 2 62 WNW 1 14 34 27 14 9 99 NW 0 7 17 12 13 2 51 NNW 0 10 36 33 15 3 97 Variable 0 0 0 0 0 0 0 Total 10 195 398 247 87 24 961 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 F-18

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Slightly Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 12 7 0 0 0 21 NNE 0 5 6 0 0 0 11 NE 1 3 3 0 0 0 7 ENE 0 5 21 5 0 0 31 E 2 15 36 3 0 0 56 ESE 1 5 11 4 0 0 21 SE 3 12 3 1 0 0 19 SSE 5 14 14 6 0 0 39 S 1 9 12 8 1 0 31 SSW 2 14 15 14 2 1 48 SW 2 5 17 25 2 1 52 WSW 1 10 24 15 0 0 50 W 5 10 25 10 0 0 50 WNW 1 10 14 18 1 1 45 NW 2 7 6 2 0 0 17 NNW 1 6 11 0 0 0 18 Variable 0 0 0 0 0 0 0 Total 29 142 225 111 6 3 516 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 F-19

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Moderately Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 0 0 0 0 1 NE 0 1 0 0 0 0 1 ENE 0 3 2 0 0 0 5 E 2 21 16 0 0 0 39 ESE 1 15 10 0 0 0 26 SE 0 9 12 0 0 0 21 SSE 1 16 9 0 0 0 26 S 1 10 0 2 0 0 13 SSW 0 10 7 11 0 0 28 SW 2 10 9 4 0 0 25 WSW 1 12 20 1 0 0 34 W 1 12 28 0 0 0 41 WNW 0 18 3 0 0 0 21 NW 2 0 0 0 0 0 2 NNW 1 3 0 0 0 0 4 Variable 0 0 0 0 0 0 0 Total 12 141 116 18 0 0 287 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 F-20

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Extremely Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 0 0 0 0 1 E 0 10 4 0 0 0 14 ESE 0 16 3 0 0 0 19 SE 1 14 3 0 0 0 18 SSE 0 18 1 0 0 0 19 S 0 8 2 0 0 0 10 SSW 0 3 3 0 0 0 6 SW 0 4 2 0 0 0 6 WSW 0 5 5 0 0 0 10 W 1 3 4 0 0 0 8 WNW 0 3 0 0 0 0 3 NW 2 0 0 0 0 0 2 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 4 85 27 0 0 0 116 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 F-21

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Extremely Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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: 3 F-22

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Moderately Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 0 0 0 1 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 2 2 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 0 0 2 3 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 F-23

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Slightly Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 0 0 3 1 4 NNE 0 0 0 0 2 0 2 NE 0 0 2 2 1 0 5 ENE 0 0 0 4 1 0 5 E 0 0 1 3 0 0 4 ESE 0 0 0 0 0 0 0 SE 0 0 0 0 2 0 2 SSE 0 0 1 0 1 1 3 S 0 0 0 0 1 0 1 SSW 0 0 1 0 2 0 3 SW 0 0 1 3 3 2 9 WSW 0 0 0 1 2 1 4 W 0 0 0 2 1 0 3 WNW 0 0 0 3 1 0 4 NW 0 0 0 0 1 0 1 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 6 18 21 5 50 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 F-24

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Neutral - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 10 16 21 5 5 57 NNE 0 7 13 23 19 7 69 NE 0 9 16 39 27 0 91 ENE 0 14 10 32 38 1 95 E 0 3 14 39 17 1 74 ESE 0 5 11 19 7 0 42 SE 1 12 28 13 12 4 70 SSE 0 13 16 28 19 8 84 S 0 7 19 26 15 4 71 SSW 5 10 16 26 5 11 73 SW 0 8 16 22 9 12 67 WSW 1 6 24 24 12 8 75 W 0 12 16 25 13 13 79 WNW 1 11 15 42 27 20 116 NW 0 6 21 40 25 26 118 NNW 0 2 12 37 19 17 87 Variable 0 0 0 0 0 0 0 Total 8 135 263 456 269 137 1268 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 F-25

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Slightly Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 1 5 6 12 1 25 NNE 0 1 7 5 0 0 13 NE 0 2 5 4 0 0 11 ENE 0 1 4 14 3 0 22 E 0 0 7 22 8 0 37 ESE 0 1 7 24 11 0 43 SE 0 5 11 11 16 1 44 SSE 1 5 6 13 7 4 36 S 0 4 7 16 10 6 43 SSW 1 3 11 13 6 14 48 SW 0 6 14 21 20 22 83 WSW 0 1 10 15 11 7 44 W 1 2 14 21 27 5 70 WNW 0 3 7 27 14 10 61 NW 1 4 12 18 9 7 51 NNW 1 4 3 5 0 1 14 Variable 0 0 0 0 0 0 0 Total 5 43 130 235 154 78 645 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 F-26

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Moderately Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 1 0 0 0 2 ENE 0 0 0 0 0 0 0 E 0 2 0 6 0 0 8 ESE 0 0 3 5 3 0 11 SE 1 1 7 27 7 0 43 SSE 0 1 2 12 6 0 21 S 0 6 5 6 0 0 17 SSW 0 1 5 9 3 3 21 SW 0 2 8 4 1 1 16 WSW 1 0 6 2 0 0 9 W 0 2 1 5 12 0 20 WNW 1 0 2 2 8 3 16 NW 0 1 4 4 0 0 9 NNW 0 2 0 3 0 0 5 Variable 0 0 0 0 0 0 0 Total 3 19 44 87 40 7 200 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 F-27

LaSalle County Generating Station Period of Record: April - June 2020 Stability Class - Extremely Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 3 1 0 0 4 SSE 0 0 0 6 0 0 6 S 0 0 0 2 0 0 2 SSW 0 0 0 1 1 0 2 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 1 0 0 0 1 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 4 10 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: 3 F-28

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Extremely Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 0 0 0 1 SSW 0 0 3 0 0 0 3 SW 0 0 5 3 1 0 9 WSW 0 1 5 2 0 0 8 W 0 0 3 0 0 0 3 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 17 5 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: 0 F-29

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Moderately Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 5 0 0 0 5 E 0 0 1 0 0 0 1 ESE 0 0 2 0 0 0 2 SE 0 0 0 0 0 0 0 SSE 0 2 3 2 0 0 7 S 0 3 5 5 0 0 13 SSW 0 3 19 0 0 0 22 SW 0 3 6 4 0 0 13 WSW 0 5 12 3 1 0 21 W 0 5 8 3 0 0 16 WNW 0 1 0 5 0 0 6 NW 0 0 0 2 0 0 2 NNW 0 0 0 1 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 22 61 25 1 0 109 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 F-30

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Slightly Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 1 2 0 0 0 3 NNE 0 2 1 0 0 0 3 NE 0 8 4 0 0 0 12 ENE 0 2 8 2 0 0 12 E 0 6 7 0 0 0 13 ESE 0 3 2 0 0 0 5 SE 0 2 2 4 0 0 8 SSE 0 7 6 0 0 0 13 S 0 6 14 1 0 0 21 SSW 0 3 10 1 0 0 14 SW 0 9 11 0 0 0 20 WSW 1 5 10 1 1 0 18 W 0 10 11 1 0 0 22 WNW 0 4 7 4 1 0 16 NW 0 2 6 6 0 0 14 NNW 0 2 1 3 0 0 6 Variable 0 0 0 0 0 0 0 Total 1 72 102 23 2 0 200 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 F-31

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Neutral - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 29 32 5 0 0 66 NNE 1 32 34 2 0 0 69 NE 1 14 34 7 0 0 56 ENE 1 17 34 7 0 0 59 E 2 30 20 2 0 0 54 ESE 0 16 8 3 0 0 27 SE 2 9 14 1 0 0 26 SSE 2 22 19 0 0 0 43 S 2 10 24 9 1 0 46 SSW 1 18 19 4 0 0 42 SW 0 11 25 1 0 0 37 WSW 1 14 19 6 0 0 40 W 1 22 19 4 3 0 49 WNW 0 3 19 10 2 2 36 NW 1 8 16 10 2 1 38 NNW 0 11 47 9 0 1 68 Variable 0 0 0 0 0 0 0 Total 15 266 383 80 8 4 756 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 F-32

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Slightly Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 29 6 0 0 0 36 NNE 2 14 11 0 0 0 27 NE 2 12 7 0 0 0 21 ENE 1 9 17 1 0 0 28 E 0 25 12 0 0 0 37 ESE 1 9 3 0 0 0 13 SE 5 6 4 0 0 0 15 SSE 2 13 5 1 0 0 21 S 3 15 5 4 0 0 27 SSW 2 17 26 12 0 0 57 SW 4 15 26 17 0 0 62 WSW 2 8 8 3 0 0 21 W 1 10 21 0 3 0 35 WNW 0 15 6 0 0 0 21 NW 1 2 16 0 0 0 19 NNW 1 12 10 1 0 0 24 Variable 0 0 0 0 0 0 0 Total 28 211 183 39 3 0 464 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 F-33

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Moderately Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 8 1 0 0 0 10 NNE 2 10 0 0 0 0 12 NE 1 1 0 0 0 0 2 ENE 2 7 0 0 0 0 9 E 3 29 4 0 0 0 36 ESE 0 17 0 0 0 0 17 SE 2 9 0 0 0 0 11 SSE 3 12 1 0 0 0 16 S 2 26 3 0 0 0 31 SSW 0 27 7 0 0 0 34 SW 1 16 22 0 0 0 39 WSW 2 14 9 0 0 0 25 W 1 18 6 0 0 0 25 WNW 0 14 3 0 0 0 17 NW 0 4 0 0 0 0 4 NNW 1 9 2 0 0 0 12 Variable 0 0 0 0 0 0 0 Total 21 221 58 0 0 0 300 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 F-34

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Extremely Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 0 0 0 0 0 1 E 0 16 0 0 0 0 16 ESE 0 28 2 0 0 0 30 SE 2 22 2 0 0 0 26 SSE 2 35 8 0 0 0 45 S 2 41 5 0 0 0 48 SSW 0 49 7 0 0 0 56 SW 0 35 31 0 0 0 66 WSW 1 19 12 0 0 0 32 W 1 20 1 0 0 0 22 WNW 0 7 0 0 0 0 7 NW 2 0 0 0 0 0 2 NNW 0 4 0 0 0 0 4 Variable 0 0 0 0 0 0 0 Total 11 276 68 0 0 0 355 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 F-35

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Extremely Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 F-36

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Moderately Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 0 0 1 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 1 0 0 1 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 F-37

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Slightly Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 2 1 0 0 3 E 0 0 0 0 0 0 0 ESE 0 0 1 1 0 0 2 SE 0 0 0 0 0 0 0 SSE 0 0 0 2 0 0 2 S 0 0 0 2 1 0 3 SSW 0 0 6 2 0 0 8 SW 0 0 3 4 1 0 8 WSW 0 0 3 3 0 0 6 W 0 1 7 0 0 0 8 WNW 0 0 1 1 0 0 2 NW 0 0 0 2 2 0 4 NNW 0 0 0 2 0 0 2 Variable 0 0 0 0 0 0 0 Total 0 1 23 20 4 0 48 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 F-38

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Neutral - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 17 23 24 0 0 64 NNE 1 23 21 17 11 0 73 NE 0 12 9 48 12 2 83 ENE 1 20 11 40 9 2 83 E 2 17 38 9 2 0 68 ESE 0 15 12 8 0 0 35 SE 1 10 6 13 1 0 31 SSE 2 11 31 6 1 0 51 S 0 13 28 22 7 1 71 SSW 0 15 24 34 4 4 81 SW 0 13 27 29 7 3 79 WSW 1 10 34 17 8 1 71 W 1 20 32 20 2 3 78 WNW 0 14 17 19 8 6 64 NW 0 7 15 23 17 4 66 NNW 0 3 30 23 4 1 61 Variable 0 0 0 0 0 0 0 Total 9 220 358 352 93 27 1059 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 F-39

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Slightly Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 3 6 15 7 1 32 NNE 2 4 14 9 7 0 36 NE 1 7 6 11 8 0 33 ENE 1 7 24 13 2 0 47 E 0 4 31 19 3 0 57 ESE 0 4 17 9 2 0 32 SE 1 3 1 12 2 0 19 SSE 0 7 6 3 1 0 17 S 0 6 13 12 4 2 37 SSW 2 0 19 23 19 9 72 SW 1 3 23 22 20 13 82 WSW 1 3 6 17 8 3 38 W 2 3 11 15 2 5 38 WNW 0 1 2 21 1 0 25 NW 0 3 7 12 4 0 26 NNW 1 4 5 9 9 2 30 Variable 0 0 0 0 0 0 0 Total 12 62 191 222 99 35 621 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 F-40

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Moderately Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 2 0 3 0 0 6 NNE 0 3 4 1 0 0 8 NE 1 2 1 1 0 0 5 ENE 2 0 4 1 0 0 7 E 0 1 5 8 0 0 14 ESE 0 2 9 20 2 0 33 SE 0 0 5 13 1 0 19 SSE 0 0 12 12 2 3 29 S 0 0 18 19 5 1 43 SSW 0 3 20 24 6 0 53 SW 0 2 34 30 10 3 79 WSW 1 1 13 11 18 1 45 W 0 2 6 13 1 0 22 WNW 1 1 8 7 1 0 18 NW 0 1 8 18 2 0 29 NNW 2 3 1 10 0 0 16 Variable 0 0 0 0 0 0 0 Total 8 23 148 191 48 8 426 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 F-41

LaSalle County Generating Station Period of Record: July - September 2020 Stability Class - Extremely Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 0 0 0 0 0 1 E 0 0 0 0 0 0 0 ESE 0 0 1 3 1 0 5 SE 0 0 1 5 6 1 13 SSE 0 0 0 6 4 0 10 S 0 0 1 2 4 0 7 SSW 0 0 1 6 0 0 7 SW 0 0 1 4 0 0 5 WSW 0 0 0 0 0 0 0 W 0 0 1 2 0 0 3 WNW 0 0 1 0 0 0 1 NW 0 0 0 1 0 0 1 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 1 0 7 29 15 1 53 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 F-42

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Extremely Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 0 0 1 SSW 0 0 0 0 2 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 0 0 1 2 0 3 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 F-43

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Moderately Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 3 5 0 8 SSW 0 0 1 1 3 1 6 SW 0 0 0 2 0 0 2 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 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 7 8 1 17 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 F-44

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Slightly Unstable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 0 0 0 1 SSE 0 0 0 0 0 0 0 S 0 0 3 2 4 0 9 SSW 0 1 1 8 4 4 18 SW 0 0 2 4 2 0 8 WSW 0 0 5 5 0 0 10 W 0 0 0 6 1 0 7 WNW 0 0 1 2 3 0 6 NW 0 0 0 0 1 0 1 NNW 0 0 1 0 0 0 1 Variable 0 0 0 0 0 0 0 Total 0 1 14 27 15 4 61 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 F-45

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Neutral - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 4 51 35 10 0 0 100 NNE 0 28 32 3 0 0 63 NE 2 5 16 10 1 0 34 ENE 1 9 21 19 2 0 52 E 1 8 15 10 0 0 34 ESE 0 5 7 2 1 0 15 SE 2 2 5 13 1 0 23 SSE 0 2 4 14 9 0 29 S 0 4 6 10 12 6 38 SSW 0 6 15 19 4 7 51 SW 1 7 21 22 1 4 56 WSW 3 12 24 15 1 1 56 W 0 19 35 25 13 15 107 WNW 3 19 53 64 17 2 158 NW 1 18 39 29 3 2 92 NNW 4 19 58 52 6 0 139 Variable 0 0 0 0 0 0 0 Total 22 214 386 317 71 37 1047 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 F-46

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Slightly Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 20 9 0 0 0 31 NNE 1 4 2 0 0 0 7 NE 1 0 2 0 0 0 3 ENE 1 2 5 1 0 0 9 E 1 4 11 3 0 0 19 ESE 0 1 6 2 2 1 12 SE 1 3 4 9 2 0 19 SSE 0 8 8 8 11 0 35 S 0 1 11 21 19 0 52 SSW 0 3 21 37 16 2 79 SW 1 6 15 29 8 1 60 WSW 1 3 11 21 2 1 39 W 0 7 24 10 11 8 60 WNW 2 22 22 8 9 9 72 NW 0 10 16 0 0 0 26 NNW 0 5 3 0 0 0 8 Variable 0 0 0 0 0 0 0 Total 11 99 170 149 80 22 531 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 F-47

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Moderately Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 1 11 0 0 0 0 12 NNE 2 1 1 0 0 0 4 NE 1 0 0 0 0 0 1 ENE 0 1 0 0 0 0 1 E 1 3 7 0 0 0 11 ESE 2 6 3 0 0 0 11 SE 0 15 9 0 0 0 24 SSE 0 1 10 3 0 0 14 S 1 8 12 4 0 0 25 SSW 0 14 13 14 2 0 43 SW 0 8 6 19 0 0 33 WSW 0 7 18 11 0 0 36 W 0 14 24 3 0 0 41 WNW 0 16 15 1 0 0 32 NW 1 7 2 0 0 0 10 NNW 0 7 3 0 0 0 10 Variable 0 0 0 0 0 0 0 Total 9 119 123 55 2 0 308 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 F-48

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Extremely Stable - 200Ft-33Ft Delta-T (F)

Winds Measured at 33 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 1 0 0 0 0 1 ENE 0 0 0 0 0 0 0 E 0 6 3 0 0 0 9 ESE 0 4 5 0 0 0 9 SE 1 11 6 0 0 0 18 SSE 0 14 16 0 0 0 30 S 0 12 16 1 0 0 29 SSW 0 14 29 11 0 0 54 SW 1 4 17 7 1 0 30 WSW 0 4 20 6 0 0 30 W 0 12 4 0 0 0 16 WNW 0 5 1 0 0 0 6 NW 3 1 0 0 0 0 4 NNW 0 2 0 0 0 0 2 Variable 0 0 0 0 0 0 0 Total 5 90 117 25 1 0 238 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 F-49

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Extremely Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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: 3 F-50

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Moderately Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 1 SW 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 W 0 0 0 0 0 1 1 WNW 0 0 0 0 0 0 0 NW 0 0 0 0 0 1 1 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 0 0 0 3 3 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 F-51

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Slightly Unstable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 0 3 4 SSW 0 0 0 1 0 2 3 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 2 2 NNW 0 0 0 0 0 0 0 Variable 0 0 0 0 0 0 0 Total 0 0 0 2 0 7 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: 3 F-52

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Neutral - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 13 33 34 16 4 100 NNE 1 10 34 14 6 0 65 NE 1 5 8 28 9 7 58 ENE 0 5 9 32 12 3 61 E 0 5 7 17 4 0 33 ESE 0 5 4 4 3 4 20 SE 0 3 2 2 12 2 21 SSE 0 1 3 9 10 9 32 S 1 3 6 10 12 32 64 SSW 0 2 5 17 21 31 76 SW 1 4 15 33 10 7 70 WSW 2 6 14 36 9 6 73 W 1 7 25 25 19 34 111 WNW 1 11 21 52 39 39 163 NW 2 11 33 55 31 11 143 NNW 1 10 25 34 19 13 102 Variable 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: 4 F-53

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Slightly Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 2 1 5 18 4 0 30 NNE 0 5 4 3 4 0 16 NE 1 0 7 2 2 0 12 ENE 0 0 3 2 0 0 5 E 1 0 3 6 7 0 17 ESE 0 2 2 7 4 0 15 SE 1 2 2 12 4 3 24 SSE 1 1 3 8 12 10 35 S 0 0 4 6 12 46 68 SSW 0 4 6 4 15 53 82 SW 0 5 13 11 21 49 99 WSW 1 3 7 11 18 18 58 W 1 4 1 15 20 10 51 WNW 0 2 12 22 13 16 65 NW 1 1 13 22 12 1 50 NNW 0 2 5 20 1 0 28 Variable 0 0 0 0 0 0 0 Total 9 32 90 169 149 206 655 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 F-54

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Moderately Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 Feet Wind Speed (in mph)

Wind Direction 1-3 4-7 8-12 13-18 19-24 > 24 Total N 0 0 2 1 3 0 6 NNE 0 0 2 1 0 0 3 NE 0 2 1 3 0 1 7 ENE 0 1 3 1 0 0 5 E 0 1 2 0 0 0 3 ESE 0 0 1 0 5 1 7 SE 0 1 1 3 4 3 12 SSE 0 2 3 4 7 4 20 S 0 0 9 7 15 1 32 SSW 1 1 3 5 7 14 31 SW 0 3 8 1 11 18 41 WSW 0 1 1 10 6 13 31 W 0 0 1 5 2 3 11 WNW 0 1 4 8 8 0 21 NW 0 0 0 14 9 0 23 NNW 0 1 2 6 1 0 10 Variable 0 0 0 0 0 0 0 Total 1 14 43 69 78 58 263 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 F-55

LaSalle County Generating Station Period of Record: October - December 2020 Stability Class - Extremely Stable - 375Ft-33Ft Delta-T (F)

Winds Measured at 375 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 1 0 1 0 0 2 E 0 0 0 1 0 0 1 ESE 0 0 1 1 0 0 2 SE 0 0 0 2 4 1 7 SSE 0 0 1 6 1 1 9 S 0 0 0 1 7 3 11 SSW 0 0 2 1 1 0 4 SW 0 0 2 6 7 0 15 WSW 0 0 2 5 3 0 10 W 0 0 1 5 4 1 11 WNW 0 1 2 2 0 0 5 NW 0 0 3 1 0 0 4 NNW 1 0 0 0 0 0 1 Variable 0 0 0 0 0 0 0 Total 1 2 14 32 27 6 82 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 F-56

APPENDIX G ERRATA DATA

Intentionally left blank There is no errata data for 2020.

G-1

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

Intentionally left blank Docket No: 50-373 50-374 LASALLE COUNTY STATION UNITS 1 and 2 Annual Radiological Groundwater Protection Program Report 1 January through 31 December 2020 Prepared By Teledyne Brown Engineering Environmental Services LaSalle County Station Marseilles, IL 61341 May 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 .......................................................................................... 7

1. Background Concentrations of Tritium ...................................................... 7 IV. Results and Discussion........................................................................................... 10 A. Groundwater Results ........................................................................................ 10 B. Surface Water Results ...................................................................................... 11 C. Drinking Water Well Survey .............................................................................. 11 D. Summary of Results - Inter-laboratory Comparison Program ............................. 11 E. Leaks, Spills, and Releases................................................................................ 11 F. Trends................................................................................................................ 11 G. Investigations..................................................................................................... 12 H. Actions Taken .................................................................................................... 12 i

Appendices Appendix A Location Designation Tables Table A-1 LaSalle County Station Groundwater Monitoring Sample Point List, 2020 Figures Figure A-1 LaSalle County Station Map of Groundwater Monitoring Sampling Locations, 2020 Appendix B Data Tables Tables Table B-I.1 Concentrations of Tritium, Strontium, Gross Alpha, and Gross Beta in Groundwater Samples Collected in the Vicinity of LaSalle County Station, 2020 Table B-I.2 Concentrations of Gamma Emitters in Groundwater Samples Collected in the Vicinity of LaSalle County Station, 2020 Table B-I.3 Concentrations of Hard-to-Detects in Groundwater Samples Collected as Part of the Radiological Groundwater Protection Program, LaSalle County Station, 2020 ii

I. Summary and Conclusions In 2006, Exelon instituted a comprehensive program to evaluate the impact of station operations on groundwater and surface water in the vicinity of LaSalle County Station. This evaluation involved numerous station personnel and contractor support personnel. Following baseline sampling and subsequent recommendations, LaSalles Radiological Groundwater Protection Program (RGPP) program now consists of the four surface water and twenty groundwater well sampling locations. The results for LaSalles RGPP sampling efforts in 2020 are included in this report.

This is the twelfth in a series of annual reports on the status of the RGPP conducted at LaSalle County 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, 237 analyses were performed on 47 samples from 19 groundwater locations. The monitoring was conducted by station personnel.

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

Strontium-89 (Sr-89) and strontium-90 (Sr-90) were not detected in any groundwater samples during 2020.

No gamma-emitting radionuclides attributable to licensed plant operations were detected in any of the groundwater or surface water samples.

In the case of tritium, Exelon specified that its laboratories achieve a lower limit of detection (LLD) 100 times lower than that required by federal regulation. The United States Environmental Protection Agency (USEPA) drinking water standard (and the Nuclear Regulatory Commission Reporting Limit) is 20,000 pCi/L.

Tritium levels were detected at concentrations greater than the LLD of 200 pCi/L in 17 of 47 groundwater samples analyzed. The tritium concentrations ranged from

<LLD to 5,620 +/- 617 pCi/L. The elevated tritium levels (>200 pCi/L) being observed in groundwater are associated with the U1 CY tank leak that occurred in the June/July 2010 timeframe, as documented in the Stations 10 CFR 50.75(g) report.

Gross alpha and gross beta analyses in the dissolved and suspended fractions were performed on groundwater samples throughout the year in 2020. Gross alpha (dissolved) was detected in 2 of 13 samples affecting 2 of 12 groundwater locations analyzed. The concentrations ranged from 1.1 to 11.6 pCi/L. Gross alpha (suspended) was detected in 3 of 13 samples affecting 3 of 12 groundwater locations analyzed. The concentrations ranged from 2.8 to 4.1 pCi/L.

Gross beta (dissolved) was detected in 9 of 13 samples affecting 7 of 12 groundwater locations analyzed. The concentrations ranged from 2.6 to 12.2 pCi/L. Gross beta (suspended) was detected in 6 of 13 samples affecting 6 of 12 groundwater locations analyzed. The concentrations ranged from 1.6 to 14.7 pCi/L.

Hard-to-detect analyses were performed on 12 of the groundwater sampling locations in accordance with the LaSalle RGPP and to aid in establishing background levels. The analyses included Fe-55, Ni-63, Am-241, Cm-242, Cm-243/244, Pu-238, Pu-239/240, U-234, U-235, and U-238. The isotopes of U-234 and U-238 were detected in 5 samples of each, affecting 3 of 12 groundwater locations. The U-234 concentrations ranged from 0.19 to 1.05 pCi/L.

The U-238 concentrations ranged from 0.19 to 0.89 pCi/L. U-234 and U-238 are commonly found in groundwater at low concentrations due to the naturally-occurring Radium (Uranium) Decay Series.

II. Introduction The LaSalle County Station (LSCS), consisting of two boiling water reactors, each rated for 3,546 MWt, owned and operated by Exelon Corporation, is located in LaSalle County, Illinois. Unit 1 went critical on March 16, 1982. Unit 2 went critical on December 2, 1983. The site is located in northern Illinois, approximately 75 miles southwest of Chicago, Illinois.

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 LaSalle County Station as discussed below:

1. Exelon and its consultant identified locations as described in the 2006 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.

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

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

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

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

C. Program Description

1. Sample Collection Sample locations can be found in Figure A-1, Appendix A.

Groundwater and Surface Water Samples of water are collected, managed, transported and analyzed in accordance with approved procedures following EPA methods. Both groundwater and surface samples water are collected. Sample locations, sample collection frequencies and analytical frequencies are controlled in accordance with approved station procedures. Contractor and/or station personnel are trained in the collection, preservation management, and shipment of samples, as well as in documentation of sampling events. 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 LaSalle County Station RGPP in 2020. Sample and analysis and frequency is based upon well location, assessed risk and site hydrogeology as described in the RGPP.

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

1. Concentrations of gamma emitters in groundwater

2. Concentrations of strontium in groundwater

3. Concentrations of tritium in groundwater

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

5. Concentrations of Am-241 in groundwater

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

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

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

9. Concentrations of Fe-55 in groundwater

10. Concentrations of Ni-63 in groundwater B. Data Interpretation The radiological data collected prior to LaSalle County Station becoming operational were used as a baseline with which these operational data were compared. For the purpose of this report, LaSalle County 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, precipitation, marine life, and foodstuffs. The results of the monitoring were detailed in the report entitled, Environmental Radiological Monitoring for LaSalle County Nuclear Power Station, Commonwealth Edison Company, Annual Reports for the years 1979 and 1981. The pre-operational REMP contained analytical results from samples collected from the surface water and groundwater.

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 strontium-90 comes from the former atmospheric testing of thermonuclear weapons.

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

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

b. Precipitation Data Precipitation samples are routinely collected at stations around the world for the analysis of tritium and other radionuclides. Two publicly available databases that provide tritium concentrations in precipitation are Global Network of Isotopes in Precipitation (GNIP) and 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. LaSalles 1979 or 1981 pre-operational REMP showed precipitation tritium concentrations

>300 pCi/L. 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.

Illinois River H-3 results have shown >200 pCi/L, as evidenced in LaSalles REMP program sample results. This is attributable to releases from Braidwood and Dresden upstream.

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

Analytical results and anomalies are discussed below.

Tritium Samples from 19 locations were analyzed for tritium activity. Tritium values ranged from <LLD to 5,620 pCi/L. The highest tritium activity was found at well TW-LS-118S. Based on the hydrogeological study conducted at LaSalle, there is no feasible pathway into a drinking water supply. Based on established aquifer flow paths the location most representative of potential offsite release into groundwater was also less than the detection limit. (Table B-I.1, Appendix B)

Strontium A total of 18 samples from 15 groundwater locations were analyzed for Sr-89 and Sr-90. The results were less than the required detection limit of 10 pCi/L for Sr-89 and less than the required detection limit of 1.0 pCi/liter for Sr-90. (Table B-I.1, Appendix B)

Gross Alpha and Gross Beta (dissolved and suspended)

Gross alpha and gross beta analyses in the dissolved and suspended fractions were performed on groundwater samples throughout the year in 2020. Gross alpha (dissolved) was detected in 2 of 13 samples affecting 2 of 12 groundwater locations analyzed. The concentrations ranged from 1.1 to 11.6 pCi/L. Gross alpha (suspended) was detected in 3 of 13 samples affecting 3 of 12 groundwater locations analyzed. The concentrations ranged from 2.8 to 4.1 pCi/L.

Gross beta (dissolved) was detected in 9 of 13 samples affecting 7 of 12 groundwater locations analyzed. The concentrations ranged from 2.6 to 12.2 pCi/L. Gross beta (suspended) was detected in 6 of 13 samples affecting 6 of 12 groundwater locations analyzed. The concentrations ranged from 1.6 to 14.7 pCi/L.

These concentrations of gross alpha and gross beta, which are slightly above detectable levels, are considered to be background and are not the result of plant effluents. (Table B-I.1, Appendix B)

Gamma Emitters No gamma emitting nuclides were detected in any of the samples analyzed.

(Table B-I.2, Appendix B)

Hard-To-Detect Hard-to-detect analyses were performed on 12 of the groundwater sampling locations in accordance with the LaSalle RGPP and to aid in establishing background levels. The analyses included Fe-55, Ni-63, Am-241, Cm-242, Cm-243/244, Pu-238, Pu-239/240, U-234, U-235, and U-238. U-234 was detected in 5 of 7 samples, affecting 4 of 5 groundwater locations. U-234 concentrations ranged from 0.19 to 1.05 pCi/L. U-238 was detected in 5 of 7 samples, affecting 4 of 5 groundwater locations. U-238 concentrations ranged from 0.19 to 0.89 pCi/L. U-234 and U-238 are commonly found in groundwater at low concentrations due to the naturally-occurring Radium (Uranium) Decay Series. The concentrations of U-234 and U-238 discussed above are considered to be background and are not the result of plant effluents. (Table B-1.3, Appendix B)

All other hard-to-detect nuclides were not detected at concentrations greater than their respective minimum detectable concentrations.

B. Surface Water Results No surface water samples were collected in 2020.

C. Drinking Water Well Survey A drinking water well survey was conducted during the summer 2006 by CRA (CRA 2006) around the LaSalle County Station. This survey concluded that no residents in the vicinity of the plant utilize the shallow water aquifer as a drinking water supply. Site hydrological studies of aquifer flow and permeation rates from the shallow aquifer to the deep aquifer concluded that there is no feasible dose receptor via a ground water pathway at LaSalle.

D. Summary of Results - Inter-Laboratory Comparison Program Inter-Laboratory Comparison Program results for TBE and Environmental Inc. (Midwest Labs) are presented in the AREOR.

E. Leaks, Spills, and Releases There were no new leaks identified at LaSalle Station during the reporting period.

F. Trends Analysis results from samples continue to be trended in order to assess impact to groundwater at LaSalle Station. There were no new leaks identified in the reporting period. Sample data from the plume arising from the historic 2010 U1 CY tank leak is being trended per the LaSalle RGPP.

The plume had been dispersing with groundwater flow, and extraction wells have been installed to provide additional control of the plume migration (see Section H.3. below). Currently, no tritium has migrated offsite, and tritium migration offsite is not expected.

G. Investigations No new investigations were carried out during the reporting period.

H. Actions Taken

1. Compensatory Actions No compensatory actions were taken during the reporting period.

2. Installation of Monitoring Wells No new monitoring wells have been installed during the reporting period.

3. Actions to Recover/Reverse Plumes Two (2) extraction wells (RW-LS-100S and RW-LS-101S) were installed to control the migration of the tritium plume near U1 CY tank. RW-LS-100S became operational in October 2012. RW-LS-101S became operational in April 2014.

APPENDIX A LOCATION DESIGNATION

Intentionally left blank TABLE A-1 LaSalle County Station Groundwater Monitoring Sample Point List, 2020 Site Site Type HP-2 Monitoring Well HP-5 Monitoring Well HP-7 Monitoring Well HP-10 Monitoring Well MW-LS-101S Monitoring Well MW-LS-102S Monitoring Well MW-LS-103S Monitoring Well MW-LS-104S Monitoring Well MW-LS-105S Monitoring Well MW-LS-106S Monitoring Well MW-LS-107S Monitoring Well MW-LS-108S Monitoring Well MW-LS-109S Monitoring Well MW-LS-110S Monitoring Well MW-LS-111S Monitoring Well MW-LS-112S Monitoring Well MW-LS-113S Monitoring Well RW-LS-100S Extraction Well RW-LS-101S Extraction Well SW-LS-101 Surface Water SW-LS-102 Surface Water SW-LS-103 Surface Water SW-LS-106 Surface Water TW-LS-114S Monitoring Well TW-LS-115S Monitoring Well TW-LS-116S Monitoring Well TW-LS-117S Monitoring Well TW-LS-118S Monitoring Well TW-LS-119S Monitoring Well TW-LS-120S Monitoring Well TW-LS-121S Monitoring Well A-1

A-2 Figure A-1 Ground Water and Surface Water Locations LaSalle County Station, 2020

APPENDIX B DATA TABLES

Intentionally left blank TABLE B-I.1 CONCENTRATIONS OF TRITIUM, STRONTIUM, GROSS ALPHA AND GROSS BETA IN GROUNDWATER SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE H-3 Sr-89 Sr-90 Gr-A (Dis) Gr-A (Sus) Gr-B (Dis) Gr-B (Sus)

HP-2 08/10/20 < 183 < 7.0 < 0.6 < 0.8 < 1.0 4.3 +/- 1.0 < 1.4 HP-5 08/11/20 < 185 < 9.5 < 0.9 < 0.6 < 0.9 4.1 +/- 1.2 < 1.4 HP-7 03/20/20 < 156 HP-7 08/10/20 < 181 < 7.1 < 0.7 < 0.6 < 0.9 5.6 +/- 1.2 1.6 +/- 1.0 HP-7 10/30/20 < 157 HP-10 08/10/20 < 185 < 6.3 < 0.8 < 0.6 2.8 +/- 1.2 2.9 +/- 1.1 3.0 +/- 1.2 MW-LS-104S 03/20/20 1530 +/- 209 MW-LS-104S 08/10/20 1940 +/- 258 < 7.8 < 0.9 < 0.6 < 0.9 < 1.7 1.6 +/- 1.0 MW-LS-104S 10/27/20 1470 +/- 203 < 6.7 < 0.8 < 0.8 < 0.6 < 1.3 < 1.6 MW-LS-105S 03/20/20 < 156 MW-LS-105S 08/10/20 < 185 < 8.8 < 0.7 1.1 +/- 0.7 3.7 +/- 1.8 2.6 +/- 0.9 14.7 +/- 2.1 MW-LS-105S 10/27/20 < 154 MW-LS-106S 08/11/20 < 187 MW-LS-107S 03/20/20 < 156 MW-LS-107S 08/11/20 < 184 < 7.4 < 0.9 < 4.7 4.1 +/- 2.0 7.5 +/- 2.4 5.8 +/- 2.0 MW-LS-107S 10/27/20 < 157 MW-LS-111S 08/11/20 < 183 < 3.9 < 0.9 11.6 +/- 4.7 < 2.3 12.2 +/- 3.2 14.0 +/- 3.3 OIL SEPARATOR 03/20/20 < 189 OIL SEPARATOR 08/10/20 < 183 OIL SEPARATOR 10/27/20 < 154 RW-LS-100S 03/20/20 1540 +/- 209 RW-LS-100S 08/10/20 1840 +/- 246 < 5.9 < 0.6 RW-LS-100S 10/27/20 1500 +/- 205 < 4.7 < 0.8 < 1.0 < 0.6 3.6 +/- 0.9 < 1.6 RW-LS-101S 03/20/20 1530 +/- 209 RW-LS-101S 08/10/20 1370 +/- 203 < 9.8 < 0.7 RW-LS-101S 10/27/20 921 +/- 154 < 6.2 < 0.9 < 0.8 < 0.6 4.2 +/- 0.9 < 1.6 TW-LS-114S 03/20/20 < 154 TW-LS-114S 08/10/20 < 181 TW-LS-114S 10/27/20 < 154 TW-LS-116S 03/20/20 4310 +/- 481 TW-LS-116S 08/10/20 4590 +/- 517 TW-LS-116S 08/10/20 4090 +/- 466 TW-LS-116S 10/27/20 4240 +/- 474 < 6.3 < 0.9 < 0.9 < 0.6 < 1.4 < 1.6 TW-LS-117S 03/20/20 < 160 TW-LS-117S 08/10/20 < 184 TW-LS-117S 10/27/20 < 153 < 9.5 < 0.9 TW-LS-118S 03/20/20 4040 +/- 452 TW-LS-118S 08/10/20 5360 +/- 592 TW-LS-118S 08/10/20 5620 +/- 617 TW-LS-118S 10/27/20 3270 +/- 380 < 7.5 < 0.8 < 0.7 < 0.6 < 1.0 < 1.6 TW-LS-119S 03/20/20 < 154 TW-LS-119S 08/10/20 < 183 TW-LS-119S 10/27/20 < 153 < 8.0 < 0.9 TW-LS-120S 03/20/20 < 184 TW-LS-120S 08/10/20 < 189 TW-LS-120S 10/27/20 < 155 < 8.2 < 0.9 TW-LS-121S 08/10/20 < 186 B-1

TABLE B-I.2 CONCENTRATIONS OF GAMMA EMITTERS IN GROUNDWATER SAMPLES COLLECTED IN THE VICINITY OF LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE Be-7 K-40 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 HP-2 08/10/20 < 17 < 15 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 7 < 2 < 2 < 13 < 4 HP-5 08/11/20 < 15 < 14 < 2 < 2 < 3 < 1 < 3 < 2 < 3 < 6 < 2 < 1 < 12 < 4 HP-7 08/10/20 < 17 < 17 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 7 < 2 < 2 < 14 < 5 HP-10 08/10/20 < 14 < 15 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 6 < 2 < 2 < 13 < 4 MW-LS-104S 08/10/20 < 19 < 18 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 6 < 2 < 2 < 15 < 5 MW-LS-104S 10/27/20 < 18 < 16 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 6 < 2 < 2 < 13 < 4 MW-LS-105S 08/10/20 < 17 < 16 < 2 < 2 < 4 < 2 < 4 < 2 < 3 < 6 < 2 < 2 < 14 < 4 MW-LS-106S 08/11/20 < 16 < 36 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 6 < 2 < 2 < 13 < 4 MW-LS-107S 08/11/20 < 16 < 31 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 6 < 2 < 2 < 13 < 4 MW-LS-111S 08/11/20 < 20 < 17 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 7 < 2 < 2 < 15 < 5 RW-LS-100S 08/10/20 < 16 < 29 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 6 < 2 < 2 < 14 < 5 RW-LS-100S 10/27/20 < 17 < 19 < 2 < 2 < 4 < 2 < 4 < 2 < 4 < 6 < 2 < 2 < 13 < 4 B-2 RW-LS-101S 08/10/20 < 17 < 30 < 2 < 2 < 5 < 2 < 4 < 2 < 4 < 7 < 2 < 2 < 14 < 6 RW-LS-101S 10/27/20 < 14 < 16 < 2 < 2 < 3 < 2 < 3 < 2 < 3 < 5 < 2 < 2 < 11 < 4 TW-LS-116S 10/27/20 < 17 37 +/- 25 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 6 < 2 < 2 < 12 < 4 TW-LS-118S 10/27/20 < 16 < 30 < 2 < 2 < 4 < 2 < 3 < 2 < 3 < 6 < 2 < 2 < 12 < 4

TABLE B-I.3 CONCENTRATIONS OF HARD-TO-DETECTS IN GROUNDWATER SAMPLES COLLECTED AS PART OF THE GROUNDWATER PROTECTION PROGRAM, LASALLE COUNTY STATION, 2020 RESULTS IN UNITS OF PCI/LITER +/- 2 SIGMA COLLECTION SITE DATE Am-241 Cm-242 Cm-243/244 Pu-238 Pu-239/240 U-234 U-235 U-238 Fe-55 Ni-63 HP-2 08/10/20 < 55 < 4.4 HP-5 08/10/20 < 65 < 4.2 HP-7 08/10/20 < 100 < 4.6 HP-10 08/10/20 < 86 < 4.4 MW-LS-104S 08/10/20 < 0.09 < 0.02 < 0.07 < 0.04 < 0.06 0.65 +/- 0.29 < 0.04 0.52 +/- 0.25 < 53 < 4.4 MW-LS-104S 10/27/20 < 0.05 < 0.02 < 0.09 < 0.16 < 0.13 1.05 +/- 0.28 < 0.11 0.89 +/- 0.26 < 105 < 4.8 MW-LS-105S 08/10/20 < 135 < 4.7 MW-LS-107S 08/11/20 < 75 < 4.1 MW-LS-111S 08/11/20 < 158 < 4.2 RW-LS-100S 08/10/20 < 0.18 < 0.05 < 0.05 < 0.12 < 0.17 < 0.05 < 0.09 < 0.02 < 69 < 4.7 RW-LS-100S 10/27/20 < 0.06 < 0.03 < 0.06 < 0.17 < 0.13 0.19 +/- 0.13 < 0.10 0.19 +/- 0.12 < 96 < 4.5 RW-LS-101S 08/10/20 < 0.08 < 0.02 < 0.02 < 0.09 < 0.09 0.28 +/- 0.13 < 0.08 0.25 +/- 0.12 < 113 < 4.1 RW-LS-101S 10/27/20 < 0.05 < 0.03 < 0.05 < 0.03 < 0.06 0.50 +/- 0.21 < 0.20 0.33 +/- 0.16 < 74 < 4.2 B-3 TW-LS-116S 10/27/20 < 55 < 4.9 TW-LS-118S 10/27/20 < 0.04 < 0.02 < 0.08 < 0.14 < 0.08 < 0.15 < 0.15 < 0.12 < 78 < 4.9

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