Text

2024 Annual Radiological Environmental Operating Report
	ML25120A431
Person / Time
Site:	Limerick
Issue date:	04/29/2025
From:	Gillin M; Constellation Energy Generation
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	LG-25-068
	Download: ML25120A431 (1)
	v • d • e

Constellation.

LG-25-068 April 29, 2025 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

2024 Annual Radiological Environmental Operating Report TS6.9.1.7 In accordance with the requirements of Section 6.9.1. 7 of Limerick Generating Station (LGS)

Units 1 and 2 Technical Specifications (TS) and Section 6.1 of the LGS Units 1 and 2 Offsite Dose Calculation Manual (ODCM), this letter submits the 2024 Annual Radiological Environmental Operating Report. This report provides the 2024 results for the Radiological Environmental Monitoring Program (REMP), as called for in the ODCM.

In assessing the data collected for the REMP, it has been concluded that the operation of LGS Units 1 and 2 had no adverse impact on the environment. No plant-produced fission or activation products were found in any pathway modeled by the REMP. The results of the groundwater protection program are also included in this report.

There are no commitments contained in this letter.

If you have any questions or require additional information, please contact Will Pratt at 610-718-2700.

Respectfully, Michael F. Gillin Site Vice President - Limerick Generating Station Constellation Energy Generation, LLC

Attachment:

2024 Annual Radiological Environmental Operating Report cc:

Administrator, Region I, USNRC LGS USNRC Senior Resident Inspector B. Edwards, Inspector Region I, USNRC LGS Senior Project Manager-NRR, USNRC (w/attachment)

(w/attachment)

-

l

Limerick Generating Station 2024 Docket Nos. 50-352 and 50-353 Annual Radiological Environmental Operating Report

~ Constellation.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 1 of 82 Company: Constellation Plant: Limerick Generating Station TABLE OF CONTENTS 1.0 LIST OF ACRONYMS AND DEFINITIONS................................................................................ 3 2.0 EXECUTIVE

SUMMARY

............................................................................................................ 4 2.1 Summary of Conclusions................................................................................................ 5

3.0 INTRODUCTION

........................................................................................................................ 7 4.0 SITE DESCRIPTION AND SAMPLE LOCATIONS..................................................................... 8 5.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM REQUIREMENTS.............. 10 6.0 MAPS OF COLLECTION SITES.............................................................................................. 17 7.0 REPORTING LEVELS FOR RADIOACTIVITY CONCENTRATIONS IN ENVIRONMENTAL SAMPLES................................................................................................. 20 8.0 SAMPLING PROGRAM, PROGRAM MODIFICATION AND INTEPRETATION OF RESULTS................................................................................................................................ 21 8.1 Environmental Direct Radiation Dosimetry Results....................................................... 21 8.2 Air Particulate and Radioiodine Sample Results........................................................... 22 8.3 Waterborne Sample Results......................................................................................... 23 8.4 Ingestion Pathway Sample Results............................................................................... 26 9.0 LAND USE CENSUS............................................................................................................... 27 10.0 SAMPLE DEVIATIONS, ANOMALIES AND UNAVAILABILITY................................................ 28 11.0 OTHER SUPPLEMENTAL INFORMATION............................................................................. 30 11.1 Offsite Dose Calculation Manual (ODCM) Changes..................................................... 30 11.2 NEI 07-07 Onsite Radiological Groundwater Monitoring Program................................. 30 11.3 Independent Spent Fuel Storage Installation (ISFSI) Monitoring Program.................... 34 11.4 Corrections to Previous Reports................................................................................... 34 12.0 BIBLIOGRAPHY...................................................................................................................... 37 TABLES Table 1, Radiological Environmental Monitoring Program - Direct Radiation......................................... 9 Table 2, Radiological Environmental Monitoring Program - Airborne................................................... 10 Table 3, Radiological Environmental Monitoring Program - Waterborne............................................. 11 Table 4, Radiological Environmental Monitoring Program - Ingestion.................................................. 12 Table 5, REMP Sampling Locations - Direct Radiation........................................................................ 14 Table 6, Reporting Levels for Radioactivity Concentrations in Environmental Samples....................... 20 Table 7, Maximum Values for the Limit of Detection............................................................................ 20 Table 8, Land Use Census - Nearest Receptors within 5 Miles........................................................... 28 Table 9, Sample Deviation Summary................................................................................................... 29 Table 10, Monthly Sample Results....................................................................................................... 40 Table 11, Weekly Airborne Samples.................................................................................................... 47 Table 12, Quarterly isotopic data - Air (pCi/m3), Water (pCi/L)............................................................ 54 Table 13, Complete REMP Results...................................................................................................... 55 Table 14, Cross Check Intercomparison Results................................................................................. 63 Table 15, Split Sample Intercomparison Results.................................................................................. 71 I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 2 of 82 Company: Constellation Plant: Limerick Generating Station FIGURES Figure 1, Potential exposure pathways to Members of the Public due to Plant Operations [6]............... 7 Figure 2, REMP Sample Locations at Distances Less than Five Miles from the Limerick Generating Station................................................................................................................................................. 17 Figure 3, REMP Sample Locations at Distances Greater than Five Miles from the Limerick Generating Station................................................................................................................................................. 18 Figure 4, REMP Sample Locations on Site or Near the Limerick Generating Station........................... 19 Figure 5, Air Particulate: Analysis for Gross Beta, Average for Group 1 Indicator vs. Group 2 Indicator vs. Control Location............................................................................................................................. 22 Figure 6, Surface Water Tritium Results.............................................................................................. 23 Figure 7, 2024 Comparison of Beta Emitters in Split Samples CGS and TBE Analysis of 16C2.......... 24 Figure 8, Drinking Water Gross Beta Samples Control vs. Indicator Comparison................................ 25 Figure 9, Drinking Water Tritium Sample Results................................................................................. 25 Figure 10, RGPP Sample Locations...33 ATTACHMENTS, Data Table Summary.................................................................................................... 39, Complete Data Table for All Analysis Results Obtained In 2024................................... 40, Cross Check Intercomparison Program......................................................................... 59, Environmental Direct Radiation Dosimetry Results....................................................... 81 I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 3 of 82 Company: Constellation Plant: Limerick Generating Station 1.0 LIST OF ACRONYMS AND DEFINITIONS

1.

Airborne Activity Sampling: Continuous sampling of air through the collection of particulates and radionuclides on filter media.

2.

ARERR: Annual Radioactive Effluent Release Report

3.

AREOR: Annual Radiological Environmental Operating Report

4.

BWR: Boiling Water Reactor

5.

Composite Sample: A series of single collected portions (aliquots) analyzed as one sample. The aliquots making up the sample are collected at time intervals that are very short compared to the composite period.

6.

Control: A sampling station in a location not likely to be affected by plant effluents due to its distance and/or direction from the station.

7.

Curie (Ci): A measure of radioactivity equal to 3.7 x 1010 disintegrations per second or 2.22 x 1012 disintegrations per minute.

8.

Direct Radiation Monitoring: The measurement of radiation dose at various distances from the plant is assessed using Thermoluminescent Dosimeters (TLD), Optically Stimulated Luminescence Dosimeters (OSLD) and pressurized ionization chambers.

9.

EPA: Environmental Protection Agency

10.

GPI: Groundwater Protection Initiative

11.

Grab Sample: A single discrete sample drawn at one point in time.

12.

Indicator: A sampling location that is likely to be affected by plant effluents due to its proximity and/or direction from the plant.

13.

Ingestion Pathway: The ingestion pathway includes milk, fish, drinking water and garden produce. Also sampled (under special circumstances) are other media such as vegetation or animal products when additional information about particular radionuclides is needed.

14.

ISFSI: Independent Spent Fuel Storage Installation

15.

Lower Limit of Detection (LLD): An a priori measure of the detection capability of a radiochemistry measurement based on instrument setup, calibration, background, decay time, and sample volume. An LLD is expressed as an activity concentration. The MDA is used for reporting results. LLD are specified by a regulator, such as the NRC and are typically listed in the ODCM.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 4 of 82 Company: Constellation Plant: Limerick Generating Station

16.

MDA: Minimum Detectable Activity. For radiochemistry instruments, the MDA is the a posteriori minimum concentration that a counting system detects. It is the smallest concentration or activity of radioactive material in a sample that will yield a net count above instrument background and that is detected with 95%

probability, with only five % probability of falsely concluding that a blank observation represents a true signal.

17.

MDC: Minimum Detectable Concentration. This is essentially synonymous with MDA for the purposes of radiological monitoring.

18.

Mean: The sum of all of the values in a distribution divided by the number of values in the distribution, synonymous with average.

19.

Microcurie: 3.7 x 104 disintegrations per second, or 2.22 x106 disintegrations per minute.

20.

N/A: Not Applicable

21.

NEI: Nuclear Energy Institute

22.

NIST: National Institute of Standards and Technology

23.

NRC: Nuclear Regulatory Commission

24.

ODCM: Offsite Dose Calculation Manual

25.

OSLD: Optically Stimulated Luminescence Dosimeter

26.

pCi/L: picocuries / Liter

27.

PWR: Pressurized Water Reactor

28.

REMP: Radiological Environmental Monitoring Program

29.

TLD: Thermoluminescent Dosimeter 2.0 EXECUTIVE

SUMMARY

LGS Radiological Environmental Monitoring Program (REMP) was established prior to the station becoming operational to provide information on background radiation present in the area. The goal of LGS REMP is to evaluate the impact of the station on the environment. Environmental samples from different media are monitored as part of the program in accordance with specifications detailed in the Offsite Dose Calculation Manual (ODCM) [27] and other site-specific requirements. The program compares data from indicator locations near the plant, to Control locations farther away from the site to assess operation impacts.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 5 of 82 Company: Constellation Plant: Limerick Generating Station The Annual Radiological Environmental Operating Report (AREOR) provides data obtained through analyses of environmental samples collected at LGS for the reporting period, of January 1st through December 31st, 2024. During that time period, 1658 analyses were performed on 1362 samples. In assessing all the data gathered for this report and comparing these results with preoperational data and/or 10-year average values, it was concluded that the operation of LGS did not result in detection of plant related radionuclides in the environment.

2.1 Summary of

Conclusions:

No measurable activities above background levels were detected. All values were consistent with historical results, which indicate no adverse radiological environmental impacts associated with the operation of LGS. Naturally occurring radionuclides are present in the Earth's crust and atmosphere and exist in detectable quantities throughout the world. It is common to detect naturally occurring radionuclides in many of the samples collected for REMP. Some examples of naturally occurring radionuclides that are frequently seen in samples are potassium-40, beryllium-7, actinium-228 (present as a decay product of radium-228), and radium-226.

Additionally, some relatively long-lived anthropogenic radioisotopes, such as strontium-90 and cesium-137, are also seen in some REMP samples; these radionuclides exist in measurable quantities throughout the world as a result of fallout from historic atmospheric nuclear weapons testing and other nuclear events worldwide, such as Fukushima and Chernobyl.

In 2024, Limerick Generating Station released to the environment through the radioactive effluent liquid and gaseous pathways approximately 68 curies of noble gas, fission, and activation products and approximately 62 curies of tritium.

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

Long term annual average meteorology X/Q and D/Q and actual gaseous effluent releases were used.

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

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

100 percent occupancy factor was assumed.

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

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 6 of 82 Company: Constellation Plant: Limerick Generating Station

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

The maximum calculated dose to a real individual would not exceed 0.34 mrem (total body), 1.34 mrem (organ), or 0.29 mrem (thyroid).

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

2024 Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for LGS1 Whole Body Thyroid Max Other Organ Limit 25 mrem 75 mrem 25 mrem Gaseous - Noble Gas 5.00E-03 5.00E-03 8.29E-03 Gaseous - Particulates & Iodine 1.50E-03 1.57E-03 1.50E-03 Carbon-14 2.43E-01 2.43E-01 1.21E+00 Liquid 7.32E-02 2.16E-02 1.05E-01 Direct Shine 0

0 0

Total Site Dose 3.23E-01 2.71E-01 1.32E+00

% Contribution of Carbon-14 to Gaseous Dose 75 90 92 Nearby Facility 1.79E-02 1.79E-02 1.79E-02 Total w/Other Nearby Facility2 3.41E-01 2.89E-01 1.34+00

% of Limit 1.36 0.39 5.37 1 2024 Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for LGS is a summation of Units to show compliance with 40 CFR Part 190 Limits.

2 Other fuel cycle sources within 5 miles of the site are considered in this analysis.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 7 of 82 Company: Constellation Plant: Limerick Generating Station

3.0 INTRODUCTION

The Radiological Environmental Monitoring Program (REMP) provides data on measurable levels of radiation and radioactive materials in the environment. This program also evaluates the relationship between quantities of radioactive materials released from the plant and resultant doses to individuals from principal pathways of exposure. In this capacity, REMP provides a check on the effluent release program and dispersion modeling to ensure that concentrations in the environment due to radioactive effluents conform to the As Low as Is Reasonably Achievable (ALARA) design objectives of 10 CFR 50, Appendix I [1], and implements the requirements of Section IV.B.2 and IV.B.3 of Appendix I. REMP is designed to conform to the Nuclear Regulatory Commission (NRC) Regulatory Guide 4.1 [2], NUREG 1302 [4],

and the 1979 NRC Branch Technical Position [5].

Figure 1, Potential exposure pathways to Members of the Public due to Plant Operations [6]

Quality assurance aspects of the sampling program and TLD/OSLD data collection are conducted in accordance with Regulatory Guides 4.15 [7] and 4.13 [8]. REMP also adheres to the requirements of Pennsylvania, LGS Technical Specifications, and Offsite Dose Calculation Manual (ODCM). These governing documents dictate the environmental sampling, sample analysis protocols, data reporting, and quality assurance requirements for the environmental monitoring program.

The Annual Radiological Environmental Operating Report provides summaries of the environmental data from exposure pathways, interpretations of the data, and analyses of trends of the results. Routinely monitored pathways include ingestion, inhalation, and direct radiation. Routes of exposure are based on site specific information such as meteorology, receptor locations, and water usage around the plant.

l l

l 0.

0 Deposition Gaseous effiuents

~

i c:Q

- - Inge 0

\ Depo ition

\,0/

".. Inhalation o

Radiation O

Radionuclides

* ** : Behavior of radionuclides

Annual Radiological Environmental Operating Report YEAR: 2024 Page 8 of 82 Company: Constellation Plant: Limerick Generating Station 4.0 SITE DESCRIPTION AND SAMPLE LOCATIONS The Limerick Generating Station (LGS), consisting of two 3,515 MW boiling water reactors owned and operated by Constellation Energy Generation, LLC, is located adjacent to the Schuylkill River in Montgomery County, Pennsylvania. Unit No. 1 went critical on 22 December 1984. Unit No. 2 went critical on 11 August 1989. The site is located in Piedmont countryside, transversed by numerous valleys containing small tributaries that feed into the Schuylkill River.

On the eastern riverbank, elevation rises from approximately 110 to 300 feet mean sea level (MSL). On the western riverbank elevation rises to approximately 50 feet MSL to the western site boundary.

A Radiological Environmental Monitoring Program (REMP) for LGS was initiated in 1971.

Review of the 1971 through 1977 REMP data resulted in the modification of the program to comply with changes in the Environmental Report Operating License Stage (EROL) [3] and the Branch Technical Position Paper (Rev. 1, 1979) [5]. The preoperational period for most media covers the periods 1 January 1982 through 21 December 1984 and was summarized in a separate report. This report covers those analyses performed by Constellation Generation Solutions (CGS), Landauer, and Teledyne Brown Engineering (TBE)/GEL Laboratories (GEL) on samples collected during the period of January 1, 2024 through December 31, 2024.

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

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

LGS sampling media are selected based on site specific information such as meteorology, receptor locations, and water usage around the plant. Sampling and analysis frequencies are documented in the Offsite Dose Calculation Manual and site procedures. Required sampling, analysis frequencies, and location of sample collected are captured in the following tables and figures:

x Table 1, Radiological Environmental Monitoring Program - Direct Radiation x

Table 2, Radiological Environmental Monitoring Program - Airborne x

Table 3, Radiological Environmental Monitoring Program - Waterborne x

Table 4, Radiological Environmental Monitoring Program - Ingestion x

Table 5, REMP Sampling Locations - Direct Radiation x

Figure 2, REMP Sample Locations (at Distances Less than Five Miles from the Limerick Generating Station) x Figure 3, REMP Sample Locations (at Distances Greater than Five Miles from the Limerick Generating Station) x Figure 4, REMP Sample Locations (on Site or Near the Limerick Generating Station)

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 9 of 82 Company: Constellation Plant: Limerick Generating Station 5.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM REQUIREMENTS Table 1, Radiological Environmental Monitoring Program - Direct Radiation Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses Direct Radiation 40 Routine monitoring stations either with two or more dosimeters or with one instrument for measuring and recording dose rate continuously placed as follows:

(1) An inner ring of stations, one in each meteorological sector in the general area of the SITE BOUNDARY:

(2) An outer ring of stations, one in each meteorological sector, in the 3-9 mile range from the site (3) The balance of the stations placed in special interest areas, such as population centers, nearby residences, schools and in 1 or 2 areas to serve as control stations See Table 5 Quarterly Gamma dose quarterly.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 10 of 82 Company: Constellation Plant: Limerick Generating Station Table 2, Radiological Environmental Monitoring Program - Airborne Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses Airborne Radioiodine and Particulates Samples from 5 locations:

3 samples from close to the 3 SITE BOUNDARY locations (in different sectors) of the highest calculated annual average ground level D/Q.

1 sample from the vicinity community having one of the highest calculated annual ground level D/Q.

1 sample from a control Location, as for example 15-30km distant and in the least prevalent wind direction.

6C1 11,305 feet NE of site Limerick Airport 10S3 2,648 feet E of site Keen Road 11S1 2,017 feet ESE of site Retired LGS Information Center 11S2 QC 2,017 feet ESE of site Retired LGS Information Center 14S1 3,319 feet SSE of site Longview Road 13S4 1,186 feet SE of site Longview Road 15D1 16,877 feet SE of site Spring City Substation 22G1 C 93,619 feet SW of site Manor Substation Continuous sampler operation with sample collection weekly, or more frequently if required by dust loading.

Radioiodine canisters:

I-131 analysis following canister change Particulate Sampler:

Gross beta radioactivity analysis following filter change:

Gamma isotopic analysis of composite (by location) at least quarterly C Indicates a Control location QC Indicates a Quality Control duplicate sample location

Annual Radiological Environmental Operating Report YEAR: 2024 Page 11 of 82 Company: Constellation Plant: Limerick Generating Station Table 3, Radiological Environmental Monitoring Program - Waterborne Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses Water

a. Surface 1 sample upstream 1 sample downstream 24S1 C 1,058 feet SW of site LGS Intake Building 13B1 9,225 feet SE of site Pennsylvania American Water Company River Sample collected from a continuous water sampler, monthly. In event sampler is inoperable, weekly grab samples will be collected until sampler returned to service.

Gamma isotopic analysis monthly.

Composite for tritium analysis quarterly.

b. Ground Samples from 1 or 2 sources only if likely to be affected No Ground water is sampled and analyzed due to no wells to which groundwater beneath the plant discharges are present in the area. The site is hydrologically isolated from all public groundwater supplies and areas of extensive groundwater development (LGS USFAR Section 2.4.13.2)

c. Drinking 1 sample of each on 1 to 3 of the nearest water supplies that could be affected by its discharge.

1 sample from a control location 15F7 33,400 feet SSE of site Phoenixville Water Treatment Plant 15F4 45,514 feet SE of site AQUA Water Company 16C2 14,034 feet SSE of site Pennsylvania American Water Company Reservoir 28F3 C 30,811 feet WNW of site Pottstown Water Sample collected from a continuous water sampler, monthly. In event sampler is inoperable, weekly grab samples will be collected until sampler returned to service I-131 analysis on each composite when the dose calculated for the consumption of the water is greater than 1 mrem per year.

Composite for gross beta and gamma isotopic analysis monthly.

Composite for tritium analysis quarterly.

d. Sediment from shoreline 1 sample from downstream area with existing or potential recreational value.

16B2 7,128 feet SSE of site Down River from Plant Discharge Area 16C4 11,510 feet SSE of site Down River from Plant Discharge Area 33A2 C 4,435 feet NNW of site A sediment sample is taken down stream of discharge semi-annually Gamma isotopic analysis semiannually.

C Indicates a Control location I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 12 of 82 Company: Constellation Plant: Limerick Generating Station Table 4, Radiological Environmental Monitoring Program - Ingestion Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses Ingestion

a. Milk Samples from milking animals in 3 locations within 5 km distance having the highest dose potential. If there are none, then 1 sample from milking animals in each of 3 areas between 5 to 8 km distance where dose is calculated to be greater than 1 mrem per year. 1 sample from milking animals at a control location (15-30km distance) and in the least prevalent wind direction.

18E1 22,704 feet S of site Miller Farm 19B1 10,317 feet SSW of site Kolbs Farm 22B1 20,011 feet SW of site Pigeon Creek Farm 8G1 C 54,504 feet ENE of site Knechel Farm Semimonthly when animals are on pasture (April 1-Oct 1),

monthly at other times.

Gamma isotopic and I-131 analyses semimonthly when animals are on pasture : monthly at other times.

b. Fish and Invertebrates 1 sample of each commercially and recreationally important species in vicinity of plant discharge area.

1 sample of same species in area not influenced by plant discharge.

16C5 9,251 feet SE of site LGS Discharge Area 29C1 C 13,725 feet WNW of site Area not influenced by Plant Discharge Sample in season, or semiannually if they are not seasonal.

Gamma isotopic analyses on edible portions C Indicates a Control location

Annual Radiological Environmental Operating Report YEAR: 2024 Page 13 of 82 Company: Constellation Plant: Limerick Generating Station Table 4, Radiological Environmental Monitoring Program - Ingestion Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses

c. Food Products 1 sample of each principal class of food products from any area that is irrigated by water in which liquid plant wastes have been discharged Samples of 3 different kinds of broad leaf vegetation grown nearest each of 2 different offsite locations of highest predicted annual average ground level D/Q if milk sampling is not performed.

1 sample of each of the similar broad leaf vegetation grown 15-30 km distance in the least prevalent wind direction if milk sampling is not performed.

There are no downstream food products that are irrigated by water in which liquid plant wastes have been discharged.

11S3 1,848 feet ESE of site Retired LGS Information Center 13S3 1,267 feet SE of site Longview Rd at the 500kv Substation 31G1 C 71,808 feet NW of site Jollyview Farm (1560 Memorial Highway, Oley)

No broadleaf vegetation sampling is credited toward REMP because milk sampling is performed.

At time of harvest Monthly during the growing season Gamma isotopic and I-131 analyses on each sample Gamma isotopic and I-131 analyses on each sample C Indicates a Control location

Annual Radiological Environmental Operating Report YEAR: 2024 Page 14 of 82 Company: Constellation Plant: Limerick Generating Station Table 5, REMP Sampling Locations - Direct Radiation Site #

Location Type Sector Distance (in feet)

Description 36S2 Inner Ring N

3,183 Evergreen/Sanatoga Roads 3S1 Inner Ring NNE 2,301 Field NNE Sector 5S1 Inner Ring NE 2,350 Possum Hollow 7S1 Inner Ring ENE 3,099 Training Center 10S3 Inner Ring E

2,648 Keen Road 11S1 Inner Ring ESE 2,017 Retired LGS Information Center 13S2 Inner Ring SE 2,149 Longview Road 14S1 Inner Ring SSE 3,319 Longview Road 18S2 Inner Ring S

1,390 Intake Building Area 21S2 Inner Ring SSW 977 Intake Building Area 23S2 Inner Ring SW 2,793 Transmission Tower 25S2 Inner Ring WSW 2,445 Taylor House 26S3 Inner Ring W

2,088 Meteorological Tower #2 29S1 Inner Ring WNW 2,886 Field WNW Sector 31S1 Inner Ring NW 1,395 NW Sector 34S2 Inner Ring NNW 3,071 Meteorological Tower #1

Annual Radiological Environmental Operating Report YEAR: 2024 Page 15 of 82 Company: Constellation Plant: Limerick Generating Station Table 5, REMP Sampling Locations - Direct Radiation Site #

Location Type Sector Distance (in feet)

Description 36D1 Outer Ring N

18,527 Romig Road 2E1 Outer Ring NNE 25,112 Laughing Water 4E1 Outer Ring NE 25,221 Neiffer Road 7E1 Outer Ring ENE 22,489 Game Farm 10E1 Outer Ring E

20,826 Royersford Road 10F3 Outer Ring ESE 29,442 Trappe Substation 13E1 Outer Ring SE 22,772 Vaughn Road 16F1 Outer Ring SSE 26,608 Pikeland Substation 19D1 Outer Ring S

18,439 Snowden Substation 20F1 Outer Ring SSW 27,648 Sheeder Substation 24D1 Outer Ring SW 20,972 Porters Mill Road 25D1 Outer Ring WSW 21,044 Hoffecker Rd/Keim St 28D2 Outer Ring W

20,231 West Cedarville Road 29E1 Outer Ring WNW 26,110 High Substation 31D2 Outer Ring NW 20,446 Poplar Substation 34E1 Outer Ring NNW 24,243 Yarnell Road

Annual Radiological Environmental Operating Report YEAR: 2024 Page 16 of 82 Company: Constellation Plant: Limerick Generating Station Table 5, REMP Sampling Locations - Direct Radiation Site #

Location Type Sector Distance (in feet)

Description 5H1 Control NE 130,742 Birch Station 6C1 Special Interest NE 11,305 Limerick Airport 9C1 Special Interest E

11,377 Reed Road 13C1 Special Interest SE 14,980 King Road 15D1 Special Interest SE 16,877 Spring City Substation 17B1 Special Interest S

8,462 Linfield Substation 20D1 Special Interest SSW 16,157 Ellis Woods Road 31D1 Special Interest WNW 15,853 Lincoln Substation

Annual Radiological Environmental Operating Report YEAR: 2024 Page 17 of 82 Company: Constellation Plant: Limerick Generating Station 6.0 MAPS OF COLLECTION SITES Figure 2, REMP Sample Locations at Distances Less than Five Miles from the Limerick Generating Station l

l I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 18 of 82 Company: Constellation Plant: Limerick Generating Station Figure 3, REMP Sample Locations at Distances Greater than Five Miles from the Limerick Generating Station 1

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 19 of 82 Company: Constellation Plant: Limerick Generating Station Figure 4, REMP Sample Locations on Site or Near the Limerick Generating Station I

I I

RIDGE'PIKE.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 20 of 82 Company: Constellation Plant: Limerick Generating Station 7.0 REPORTING LEVELS FOR RADIOACTIVITY CONCENTRATIONS IN ENVIRONMENTAL SAMPLES Table 6, Reporting Levels for Radioactivity Concentrations in Environmental Samples Radionuclide Water (pCi/L)

Air Particulates or Gases (pCi/m3)

Fish (pCi/Kg-wet)

Milk (pCi/L)

Food Products (pCi/Kg-wet)

H-3 20,000 (1)

Mn-54 1,000 30,000 Fe-59 400 10,000 Co-58 1,000 30,000 Co-60 300 10,000 Zn-65 300 20,000 Zr-Nb-95 400 I-131 2 (2) 0.9 3

100 Cs-134 30 10 1,000 60 1,000 Cs-137 50 20 2,000 70 2,000 Ba-La-140 200 300 Table 7, Maximum Values for the Limit of Detection Radionuclide Water (pCi/L)

Air Particulates or Gases (pCi/m3)

Fish (pCi/Kg-wet)

Milk (pCi/L)

Food Products (pCi/Kg-wet)

Sediment (pCi/Kg-dry)

Gross Beta 4.0 0.01 H-3 2,000 (3)

Mn-54 15 130 Fe-59 30 260 Co-58, Co-60 15 130 Zn-65 30 260 Zr-95, Nb-95 30, 15 I-131 1 (4) 0.07 1

60 Cs-134 15 0.05 130 15 60 150 Cs-137 18 0.06 150 18 80 180 Ba-140, La-140 60, 15 15 1 For drinking water samples: If no drinking water pathway exists, a value of 30,000 pCi/L may be used.

2 If no drinking water pathway exists, a value of 20 pCi/l may be used 3 If no drinking water pathway exists, a value of 3,000 pCi/L may be used. Some states may require a lower LLD for drinking water sources-per 40 CFR 141 Safe Drinking Water Act.

4 If no drinking water pathway exists, a value of 15 pCi/l may be used I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 21 of 82 Company: Constellation Plant: Limerick Generating Station 8.0 SAMPLING PROGRAM, PROGRAM MODIFICATION AND INTEPRETATION OF RESULTS At most nuclear stations, data was collected prior to plant operation to determine background radioactivity levels in the environment. Annual data is routinely compared to preoperational and/or 10-year average values to determine if changes in the environs are present. Strict comparison is difficult to make due to fallout from historical nuclear weapon testing. Cesium-137 can be routinely found in environmental samples as a result of above ground nuclear weapons testing. It is important to note, levels of Cs-137 in the environment are observed to fluctuate, for example, as silt distributions shift due to natural erosion and transport processes. Cs-137 may or may not be observed in sediment samples. Results from samples collected and analyzed during the year 2024 are described below.

In the following sections, results from direct radiation, air, water, and food products analyzed as part of REMP in 2024 will be discussed. Sampling program descriptions and deviations will also be discussed.

8.1 Environmental Direct Radiation Dosimetry Results Dose is measured as net exposure (field reading less transit reading) normalized to 91-day quarters. Data is treated and analyzed consistent with ANSI/HPS N13.37-2014 [19], which compares the measured dose for each location to the baseline background dose for that location. Environmental dose rates vary by location, depending on geological and land use considerations, and remain relatively constant for any given location (unless land use changes). Some facilities observe seasonal variation in environmental doses. Baseline Background Doses have been determined for both quarterly and annual measurements at each location using historical field measurements.

ANSI/HPS N13.37-2014 uses the concept of minimum differential dose (MDD), which is the minimum facility-related dose that can be detected above background. Due to natural background variations and measurement sensitivities and uncertainties, minimum differential dose is not zero. MDD is calculated based on statistical performance of the dosimetry system in the environment and is site specific.

Normalized doses that exceed the Minimum Differential Dose value above the Baseline Background Dose are considered to indicate Facility-Related Dose; a quality assurance review is performed to verify that any results indicating Facility-Related Dose are accurate.

During the calendar year 2024, a total of 40 locations were monitored and data analyzed in accordance with the requirements in Table 1, Radiological Environmental Monitoring Program - Direct Radiation. Attachment 4, Environmental Direct Radiation Dosimetry Results, provides the annual direct radiation dosimetry analysis.

There was no direct radiation dose detected from the facility. All OSLD measurements were analyzed, and none were found to have radiation levels that had increased over normal background radiation levels.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 22 of 82 Company: Constellation Plant: Limerick Generating Station 8.2 Air Particulate and Radioiodine Sample Results Air particulate filters and charcoal canisters were collected from locations specified in Table 1, Radiological Environmental Monitoring Program - Direct Radiation. During the calendar year 2024, a total of 364 samples were collected and analyzed for gross beta, gamma emitters, and iodine. Particulate samplers are used to continuously collect airborne particulates on a filter. The samples are analyzed for gross beta activity following filter changeout, which occurs weekly. Gamma isotopic analysis is also performed on the samples collected at each location and is analyzed quarterly.

Air particulate samples were analyzed for concentrations of gross beta and gamma-emitting nuclides. Gross beta and cosmogenic naturally occurring beryllium-7 (Be-7) were detected at levels consistent with those detected in previous years. No fission or activation products were detected. High-sensitivity I-131 analyses were performed on weekly air samples. All I-131 results were less than minimum detectable activity.

Gross Beta results are plotted in Figure 5, below.

Figure 5, Air Particulate: Analysis for Gross Beta, Average for Group 1 Indicator vs. Group 2 Indicator vs. Control Location Air particulate and radioiodine results from this monitoring period, 2024, were compared to 10 year average as shown in Figure 5, and there were no significant changes.

0.03 0.025 0.02

~

~ 0.015 u

a.

0.01 0.005 I

I I

Air Particulate: Analysis for Gross Beta, Indicator 1 vs. Indicator 2 vs Control 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 Indicator 1 (10S3,11Sl,13S4,14S1)

Indicator 2 (6Cl, 15D1)

Control (22Gl)

Annual Radiological Environmental Operating Report YEAR: 2024 Page 23 of 82 Company: Constellation Plant: Limerick Generating Station 8.3 Waterborne Sample Results 8.3.1 Surface Water (i.e., Bay, Lake etc.)

Composite water samples are collected monthly at the upstream control location and at the downstream indicator locations. Monthly composite samples are analyzed for gamma emitters. Aliquots from the monthly composites are combined to form a quarterly composite, which is then analyzed for tritium. Tritium was not detected in any samples in 2024, as tritium concentrations were below minimum detectable activity. During the calendar year 2024, a total of 24 surface water samples were collected and analyzed in accordance with the requirements in the ODCM and shown in Table 3, Radiological Environmental Monitoring Program - Waterborne. Tritium concentrations in surface water were well below the EPA tritium drinking water limit of 20,000 pCi/L.

The ODCM does not require low level iodine analysis from locations 13B1 and 24S1.

Thus, beginning in 2024, 24S1 is no longer analyzed for low level iodine. Figure 6 shows surface water tritium results for the last 10 years.

ODCM requires gamma isotopic analysis on monthly samples and tritium analysis quarterly on composited samples. (ODCM Table 3.3-1 3.WATERBORNE, a. Surface, 4th column).

Figure 6, Surface Water Tritium Results J

0.::

~

20000 15000

~ 10000 E

~

5000 I

2015 2016 2017 I

Surface Water Tritium Data 2018 2019 2020 Indicator Control

~

EPA limit I

2021 2022 I

2023 2024

Annual Radiological Environmental Operating Report YEAR: 2024 Page 24 of 82 Company: Constellation Plant: Limerick Generating Station 8.3.2 16C2 Beta Analysis Comparison; CGS vs. TBE 2024 Constellation Generation Solutions (CGS) Laboratory participates in a split sample program with Teledyne Brown Engineering (TBE). Below is the comparison of the 2024 split sample analyses of 16C2 for beta emitters.

Figure 7, 2024 Comparison of Beta Emitters in Split Samples CGS and TBE Analysis of 16C2 8.3.3 Drinking Water A total of 48 drinking water samples were obtained in 2024. These samples were analyzed for gross beta, low level iodine, and gamma analysis monthly. These samples were analyzed for tritium quarterly in accordance with requirements in the ODCM and shown in Table 3, Radiological Environmental Monitoring Program -

Waterborne. Total gross beta activities detected were consistent with those detected in previous years. No other fission or activation products were detected. Tritium concentrations in drinking water were less than MDA, thus far below the EPA tritium drinking water limit of 20,000 pCi/L.

4.5 3.5

0 3 ___

.s

-~ 2.5 E

UJ l!l 2

co 1.5 0.5 0

I I

I 2024 Comparison of Beta Emitters in Split Samples CGS and TBE Analysis of 16C2 1/29/2024 2/29/2024 3/31/2024 4/30/2024 5/31/2024 6/30/2024 7/31/2024 8/31/2024 9/30/2024 10/31/2024 11/30/2024 12/31/20:

-t-( CG5) 16C2 (TBE)16C2 plot shown at 0.0 are <MDA

Annual Radiological Environmental Operating Report YEAR: 2024 Page 25 of 82 Company: Constellation Plant: Limerick Generating Station Figure 8, Drinking Water Gross Beta Samples Control vs. Indicator Comparison Figure 9, Drinking Water Tritium Sample Results 8.0 7.0 6.0 5.0 a-4.0 C.

3.0 2.0 1.0 0.0 25000 20000

~

115000

~

B

<t

~ 10000

~

5000 I

I I

Drinking Water Gross Beta 1-----1t---~-------l-----1--~

.. t----1----1-----

2015 2015 2016 2016 2017 2017

--Indicator 1 2018 2019 2020

,_Indicator ~

Control Drinking Water Tritium 2018 2019 2020 (plot shown at 0.0 are <MDA)

-+-Control EPALimit 2021 2021 2022 2022 2023 2023 2024 2024

Annual Radiological Environmental Operating Report YEAR: 2024 Page 26 of 82 Company: Constellation Plant: Limerick Generating Station 8.3.4 Sediment from Shoreline Shoreline sediment collections were made in June and November of 2024 and analyzed for gamma-emitting isotopes. Samples are collected at both indicator and control locations. A total of 6 shoreline samples were analyzed in accordance with requirements in the ODCM and shown in Table 3, Radiological Environmental Monitoring Program - Waterborne.

Sediment samples from all locations were analyzed for gamma-emitting nuclides. All analyses were less than minimum detectable activities. No fission or activation products were detected.

8.4 Ingestion Pathway Sample Results 8.4.1 Milk Milk samples from milking animals were collected at 3 locations within 5 km having the highest dose potential, along with samples collected from a control location 15-30 km in the least prevalent wind direction. Samples were collected and analyzed monthly when cows were not on pasture and biweekly when cows were on pasture.

Samples were analyzed for low level iodine and gamma-emitting nuclides.

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

8.4.2 Fish and Invertebrates A total of 8 fish samples were collected in 2024. These samples were analyzed for gamma emitting radionuclides in edible portions, in accordance with requirements of the ODCM and summarized in Table 4, Radiological Environmental Monitoring Program - Ingestion. These samples are collected from the indicator and control areas as required by the ODCM (with a bottom feeder species and a predator species collected at each location). All non-natural gamma emitters were less than the minimal detectable activity. Concentrations of naturally occurring potassium-40 (K-40) were consistent with those detected in previous years.

8.4.3 Food Products A total of 36 vegetation samples were analyzed in 2024 for gamma emitting radionuclides in accordance with requirements of the ODCM, as summarized in Table 4, Radiological Environmental Monitoring Program - Ingestion.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 27 of 82 Company: Constellation Plant: Limerick Generating Station 8.4.4 Leafy Vegetation In accordance with the ODCM and as described in Table 4, Radiological Environmental Monitoring Program - Ingestion, 36 broad leaf vegetation samples were collected from growing locations nearest site boundary in areas of highest predicted annual average ground level D/Q. Samples are collected and analyzed for gamma isotopic activity from the indicator and control locations monthly during growing season. It is common to detect Cs-137 in broadleaf samples at both indicator and control locations. Cs-137 can be attributed to offsite sources such as weapons testing, Chernobyl, and Fukushima events. All non-natural gamma emitters were less than the minimal detectable activity.

9.0 LAND USE CENSUS An annual land use census is required by the Offsite Dose Calculation Manual and is performed to ensure that changes in the use of areas at or beyond the site boundary are identified and modifications to REMP are made if required by changes in land use. The land use census satisfies the requirements of Section IV.B.3 of Appendix I to 10 CFR 50 [1]. NUREG-1302 Control 3.12.2 specifies that "a Land Use Census shall be conducted and shall identify within a distance of 8 km (5 mi.) the location in each of the 16 meteorological sectors of the nearest milk animal, the nearest residence and the nearest garden of greater than 50 m2 (500 ft2) producing broad leaf vegetation. Note, per NUREG-1302, broad leaf vegetation sampling of at least three different kinds of vegetation may be performed at the SITE BOUNDARY in each of two different direction sectors with the highest predicted D/Qs in lieu of the garden census.

A Land Use Census was conducted during the calendar year 2024, within the growing season, to identify changes in land use, receptor locations, and new exposure pathways. The results for the 2024 Land Use Census are listed in Table 8:

Land Use Census - Nearest Receptors within 5 miles. The nearest gardens in all other sectors reported in the 2024 report are the same as the previous years report.

There was no observed water usage for agricultural irrigation of root vegetables drawn directly from the Schuylkill River downriver from Limerick Generating Station.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 28 of 82 Company: Constellation Plant: Limerick Generating Station Table 8, Land Use Census - Nearest Receptors within 5 Miles Sector Direction Nearest Residence (Miles)

Nearest Garden (1)

(Miles)

Nearest Dairy Animal (Miles)

A N

0.63 0.63 Not Found in Sector B

NNE 0.72 0.72 Not Found in Sector C

NE 2.64 2.64 Not Found in Sector D

ENE 1.41 1.41 10.32*

E E

0.78 0.78 Not Found in Sector F

ESE 0.65 0.65 Not Found in Sector G

SE 1.21 1.21 Not Found in Sector H

SSE 1.31 1.31 Not Found in Sector J

S 1.16 1.16 4.19*

K SSW 1.09 1.09 1.97*

L SW 1.20 1.20 3.79*

M WSW 0.84 0.84 Not Found in Sector N

W 1.68 1.68 Not Found in Sector P

WNW 0.84 0.84 Not Found in Sector Q

NW 1.55 1.55 Not Found in Sector R

NNW 1.36 1.36 Not Found in Sector (1) Larger than 500 square feet (as can best be determined from a distance)

Denotes current REMP Dairy sample location Red Denotes the site/site information has been updated from the previous years Land Use Census 10.0 SAMPLE DEVIATIONS, ANOMALIES AND UNAVAILABILITY Sampling and analysis are performed for media types addressed in the Offsite Dose Calculation Manual (ODCM). Sampling and analysis challenges may be experienced due to a multitude of reasons including environmental factors, loss of OSLDs, contamination of samples, etc. To aid classification of sampling and analysis challenges experienced in 2024, the following three terms are used to describe the issues: Sample Anomalies, Sample Deviation, and Unavailable Samples.

Media that experienced downtime (i.e., air samplers or water samplers) during a surveillance period are classified a Sample Deviation." Sample Anomalies are defined as errors that were introduced to a sample once it arrived in the laboratory, errors that prevent the sample from being analyzed as it normally would, or errors that may have altered the outcome of the analysis (i.e., cross contamination, human error).

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 29 of 82 Company: Constellation Plant: Limerick Generating Station Sample Unavailability is defined as sample collection with no available sample (i.e.,

food crop, TLD).

All required samples were collected and analyzed as scheduled. There were no sample deviations or anomalies that required corrective action.

Table 9, Sample Deviation Summary Sample Type and Analysis Location Collection Date or Period Reason for not conducting REMP sampling as required by ODCM Plans for preventing reoccurrence N/A I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 30 of 82 Company: Constellation Plant: Limerick Generating Station 11.0 OTHER SUPPLEMENTAL INFORMATION 11.1 Offsite Dose Calculation Manual (ODCM) Changes Date of Change Revision Description of Change 3/18/2024 35 The ODCM revision 35 changes included revising Table A-1 Radiological Environmental Monitoring Program to remove inactive milk farm 25C1 and replace with milk farm 22B1 due to the milk farm going out of business. Revised Table A-1 Radiological Environmental Monitoring Program to remove inactive control milk farm 23F1 and replace with control milk farm 8G1 due to the milk farm going out of business. Revised Table II2-32 Nearest Gaseous Effluent Dose Receptors Distances to reflect the 2022 Land Use Census Results. Revised table to fix Table A-1 typographical error for number of TLDs at each REMP TLD location. Each TLD used to have 4 elements each, now each OSLD has 2 elements each. Revised Table A-1 to fix typographical error for airborne 6C1 sector from N to NE. Air sampler 6C1 Location is in the right sector based on coordinates and map was incorrect in Table A-1.

10/4/2024 36 The ODCM revision 36 changes included revising Table 4.2-1 "Radioactive Liquid Waste Sampling and Analysis Program". The Hold Pond sampling frequency and minimum analysis frequency of principal gamma emitters, I-131, dissolved and entrained gases (gamma emitters) was changed from D (Daily), at least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to once per calendar day. The Note g, Samples from the Hold Pond are grab samples obtained daily, was also deleted.

The Hold Pond was added to the ODCM revision 33 as a liquid discharge point. The sample table frequency in the ODCM is based on technical specifications and daily means once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . Sampling once per calendar day is a more conservative sample and analysis frequency to ensure the Hold Pond is sampled every calendar day.

11.2 NEI 07-07 Onsite Radiological Groundwater Monitoring Program Limerick Generating Station has developed a Groundwater Protection Initiative (GPI) program in accordance with NEI 07-07, Industry Ground Water Protection Initiative -

Final Guidance Document. The purpose of the GPI is to ensure timely detection and an effective response to situations involving inadvertent radiological releases to groundwater in order to prevent migration of licensed radioactive material off-site and to quantify impacts on decommissioning. It is important to note that samples and results taken in support of NEI 07-07 on-site groundwater monitoring program are separate from the Radiological Environmental Monitoring Program (REMP).

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 31 of 82 Company: Constellation Plant: Limerick Generating Station The Station conformed with its Radiological Groundwater Protection Program (RGPP) in 2024 with respect to sampling protocol. The 2024 RGPP sample locations effectively monitored Systems, Structures, and Components of the Station.

Therefore, RGPP sample locations should continue to be sampled in accordance with site procedures. Based on precipitation recapture sample results, tritium present in precipitation is not likely to adversely affect groundwater conditions at the Station.

Based on the evaluation of groundwater flow direction, the wells sampled effectively monitored groundwater conditions at the facility.

There were no spills to ground containing radioactive material in 2024.

Samples were collected from onsite wells throughout the year in accordance with the station RGPP. Analytical results and anomalies are discussed below:

RGPP Wells:

Tritium Limerick Generating Station has two background, four perimeter, and seven source designated wells that are sampled as part of the RGPP. Samples collected from source designated wells are analyzed for tritium quarterly; and samples collected from background and perimeter designated wells are analyzed for tritium annually. Samples from 13 locations were analyzed for tritium activity. Tritium values ranged from non-detectable to 3,580 pCi/L.

There is no drinking water pathway available from these groundwater sample locations.

Strontium Samples were analyzed for Sr-89 and Sr-90 and were not detected at concentrations greater than their respective LLDs in samples collected in 2024.

Gross Alpha (dissolved and suspended)

Gross-alpha (dissolved) was detected in four samples collected during the 2nd quarter 2024 RGPP sampling round. The gross-alpha concentrations did not exceed the current Alert Levels (three times the historic average).

Gamma Emitters Gamma-radionuclide analysis was performed during the 2nd quarter 2024 RGPP sampling round. Gamma radionuclides, associated with station radionuclides, were not detected at concentrations exceeding their respective LLDS in 2024. The next time gamma-radionuclide analysis will be performed is 2026.

Select Transuranics No samples were analyzed for select transuranics in 2024.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 32 of 82 Company: Constellation Plant: Limerick Generating Station Hard-To-Detect Hard-to-detect (HTD) analyses were performed in 2021 on 7 groundwater locations. Hard to detects (Fe-55 and Ni-63) were not detected at concentrations greater than their respective LLDs. The next sampling event is scheduled to take place in 2026.

Precipitation Recapture:

Tritium The Station collected precipitation recapture samples in January and July 2024. Eight samples were collected during the January and July 2024 sampling rounds. Tritium was detected in six of the eight samples collected in January 2024 with detections ranging between 214 pCi/L (RS-4, south-southwest sector) and 516 pCi/L (RS-3, southwest sector). Tritium was not detected in the samples collected during the July 2024 precipitation sampling round.

Intermittent, low-level tritium detections in monitoring well MW-LR-9 are currently being investigated. Tritium concentrations in MW-LR-9 decreased to historic concentrations since the Unit 1 Steam Seal Evaporator was temporarily repaired on December 17, 2023. As of the 4th quarter 2024, the maximum tritium concentration was 1,920 pCi/L (MW-LR-9). This is documented in issue report 04540232.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 33 of 82 Company: Constellation Plant: Limerick Generating Station Figure 10, RGPP Sample Locations I\.

Qi. ~I "i' I I

I I I

~~~:7 8---tJ

=

~

o;,

fa.

.=-,1,,_ *""'J

~

MW-LR-6 I

MW-LR-4 MW-LR-9 P14 MW-LR-10

~.

MW-LR-5

~ 400 0

MW-LR-1 *

~

Annual Radiological Environmental Operating Report YEAR: 2024 Page 34 of 82 Company: Constellation Plant: Limerick Generating Station 11.3 Independent Spent Fuel Storage Installation (ISFSI) Monitoring Program On July 21, 2008, an ISFSI pad was placed in service. The results from the dosimeter location 36S2 were used to determine the direct radiation exposure to the nearest residence from the ISFSI pad. For the 10 CFR 20.2002 permitted storage area, 0 cubic feet was placed on the pad.

11.4 Corrections to Previous Reports 11.4.1 2023 AREOR

1.

In the 2023 AREOR, it was identified that the dose totals for Tables 1 and 2 should include a summation of all (Units 0, 1, and 2) release points. The spreadsheets (for Gaseous Releases only) used to calculate these values only included Unit 0. The changes to final numbers were negligible against totals and dose limits, which resulted in them not being initially identified. Adding Unit 1 and 2 gaseous release values had no significant impact on margin to any dose limits. Specifically, all values are less than or equal to 10 percent of their applicable dose limits (in all cases less than 0.01 percent of allowed limits were observed). These errors are documented in issue report 04853176. Table 1 note 2 was removed from Gaseous - Noble Gas due to separation of gaseous effluents.

2.

In 2023, the tritium released from the U1 and U2 MTLO Exhaust Vents was greater than 1 percent when compared to all gaseous tritium released from the site. The increase of tritium in the U1 and U2 MTLO Exhaust Vents in 2023 compared to previous years was due to a decrease in the site gaseous tritium released. Per RG 1.21 Revision 2, a significant release point is when any location from which radioactive material is released, contributes greater than 1 percent of the activity discharged from all the release points for a particular type of effluent considered. A significant release point is required to be included in the dose summary tables of the AREOR. There were 12 U1 MTLO Exhaust Vent abnormal release permits and 12 U2 MTLO Exhaust Vent abnormal release permits generated for 2023. The U1 and U2 MTLO Exhaust Vents were included in the gaseous dose summary tables. These errors are documented in issue report 04798720.

3.

The corrections to the 2023 AREOR Table 1, Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for LGS and Table 2, Limerick Generating Station Site Dose Summary are as follows:

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 35 of 82 Company: Constellation Plant: Limerick Generating Station Table 1, Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for LGS1 Whole Body Thyroid Max Other Organ Limit 25 mrem 75 mrem 25 mrem Gaseous2 - Noble Gas 1.08E-03 1.08E-03 1.81E-03 Gaseous - Particulates & Iodine 1.13E-04 6.46E-04 1.79E-04 7.03E-04 1.14E-04 6.53E-04 Carbon-14 2.39E-01 2.39E-01 1.19E+00 Liquid 8.06E-03 4.91E-03 1.04E-02 Direct Shine 0

0 0

Total Site Dose 2.48E-01 2.49E-01 2.45E-01 2.46E-01 1.20E+00

% Contribution of Carbon-14 to Gaseous Dose 96 97 99 Nearby Facility 2.17E-02 2.17E-02 2.17E-02 Total w/Other Nearby Facility32 2.70E-01 2.71E-01 2.66E-01 2.67E-01 1.22E+00

% of Limit 1.08 0.36 4.90 4.88 1 Table 1 is a summation of Units to show compliance with 40 CFR Part 190 Limits.

2 Gaseous dose values in Table 1 include organ dose from Noble Gas, Iodine, Tritium, and particulates.

32 Other fuel cycle sources within 5 miles of the site are considered in this analysis.

I I

I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 36 of 82 Company: Constellation Plant: Limerick Generating Station Table 2, Limerick Generating Station Site Dose Summary1 Quarter 1 Quarter 2 Quarter 3 Quarter 4 Annual Liquid Effluents Limit 3 mrem 3 mrem 3 mrem 3 mrem 6 mrem Total Body Dose2 1.39E-04 5.37E-03 2.56E-03 1.62E-06 8.06E-03

% Of Limit 0.005 0.179 0.085

<0.001 0.134 Limit 10 mrem 10 mrem 10 mrem 10 mrem 20 mrem Maximum Organ Dose3 1.83E-04 6.75E-03 3.42E-03 1.62E-06 1.04E-02

% Of Limit 0.002 0.068 0.034

<0.001 0.052 Gaseous Effluents Limit 10 mrad 10 mrad 10 mrad 10 mrad 20 mrad Gamma Air Dose4 3.45E-04 6.35E-04 1.07E-04 5.54E-05 1.14E-03

% Of Limit 0.003 0.006 0.001 0.001 0.006 Limit 20 mrad 20 mrad 20 mrad 20 mrad 40 mrad Beta Air Dose5 2.04E-04 3.97E-04 6.39E-05 3.24E-05 6.97E-04

% Of Limit 0.001 0.002

<0.001

<0.001 0.002 Limit 5 mrem 5 mrem 5 mrem 5 mrem 10 mrem NG Total Body Dose6 3.28E-04 6.02E-04 1.02E-04 5.28E-05 1.08E-03

% Of Limit 0.007 0.012 0.002 0.001 0.011 Limit 15 mrem 15 mrem 15 mrem 15 mrem 30 mrem NG Skin Dose7 5.43E-04 1.01E-03 1.68E-04 8.76E-05 1.81E-03

% Of Limit 0.004 0.007 0.001 0.001 0.006 Limit 15 mrem 15 mrem 15 mrem 15 mrem 30 mrem Maximum Organ Dose8 1.04E-05 1.79E-05 5.99E-05 5.05E-04 4.05E-05 4.79E-05 6.78E-05 1.32E-04 1.79E-04 7.03E-04

% Of Limit

<0.001

<0.001 0.003

<0.001

<0.001 0.001 0.001 0.002 1 Table 2 demonstrates compliance with 10 CFR Part 50, App. I Limits. Carbon-14 dose is not included in this table.

2 Adult, LGS Outfall 3 Teenager, LGS Outfall, Liver 4 Site Boundary, All Age Groups 5 Site Boundary, All Age Groups 6 Site Boundary, All Age Groups 7 Site Boundary, All Age Groups 8 Child, Vegetation, Thyroid I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 37 of 82 Company: Constellation Plant: Limerick Generating Station 12.0 BIBLIOGRAPHY

[1] "10 CFR 50, Domestic Licensing of Production and Utilization Facilities", US Nuclear Regulatory Commission, Washington, DC

[2] "Regulatory Guide 4.1, Radiological Environmental Monitoring for Nuclear Power Plants, Revision 2," Nuclear Regulatory Commission, 2009

[3] Environmental Report Operating License Stage, Limerick Generating Station, Units 1 and 2, Volumes 1-5 Philadelphia Electric Company

[4] "NUREG-1302, Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Boiling Water Reactors," Nuclear Regulatory Commission, April 1991

[5] "Branch Technical Position, Regulatory Guide 4.8, Revision 1," NRC000096, Submitted March 30, 2012, November 1979

[6] "Japan Atomic Energy Agency," 06 November 2020. [Online]. Available:

https://www.jaea.go.jp/english/04/ntokai/houkan/houkan_02.html

[7] "Regulatory Guide 4.15, Quality Assurance for Radiological Monitoring Programs (Inception through Normal Operations to License Termination) -- Effluent Streams and the Environment,"

Nuclear Regulatory Commission, July, 2007

[8] "Regulatory Guide 4.13, Performance, Testing, and Procedural Specifications for Thermoluminescence Dosimetry: Environmental Applications, Revision 2," Nuclear Regulatory Commision, June, 2019

[9] "NUREG/CR-2919, XOQDOQ Computer Program for the Meteorological Evaluation of Routine Effluent Releases at Nuclear Power Stations," Nuclear Regulatory Commission, September, 1982

[10] "Measurements of Radionuclides in the environment Sampling and Analysis of plutonium in soil,"

Nuclear Regulatory Commission, 1974

[11] NCRP, "Report No. 160, Ionizing Radiation Exposure of the Population of the United States,"

National Council on Radiation Protection, Bethesda, 2009.

[12] Nuclear Regulatory Commission, 30 June 2015. [Online]. Available: http://www.nrc.gov/reading-rm/basic-ref/students/animated-pwr.html. [Accessed October 2020]

[13] "ICRP Publication 60, ICRP Publication 60: 1990 Recommendations of the International Commission on Radiological Protection, 60, Annals of the ICRP Volume 21/1-3," International Commission on Radiation Protection, October, 1991

[14] "NRC Resource Page," [Online]. Available: http://www.nrc.gov/about-nrc/radiation.html. [Accessed 10 November 2020]

[15] "NUREG-0133, Preparation of Effluent Technical Specifications for Nuclear Power Plants,"

Nuclear Regulatory Commission, 1987

[16] "Regulatory Guide 1.109, Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Demonstrating Compliance with 10 CFR Part 50, Appendix I," Nuclear Regulatory Commission, Ocotober, 1977

[17] Radiation Face Sheets, Health Physics Society, [Online]. Available:

http://hps.org/hpspublications/radiationfactsheets.html. [Accessed 2020]

[18] "NEI 07-07, Industry Ground Water Protection InitiativeFinal Guidance Document, Rev. 1,"

Nuclear Energy Institute, Washington, D.C., 2019 I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 38 of 82 Company: Constellation Plant: Limerick Generating Station

[19] "ANSI 13.37, Environmental Dosimetry-Criteria for System Design and Implementation," Health Physics Society (HPS), April, 2014

[20] "40 CFR Part 141, National Primary Drinking Water Regulations," US Environmental Protection Agency, Washington, DC

[21] Nuclear Regulatory Commission, 25 June 2015. [Online]. Available: http://www.nrc.gov/reading-rm/basic-ref/students/animated-bwr.html. [Accessed October 2020]

[22] "40 CFR 190 - Environmental Radiation Protection Standards for Nuclear Power Operation," US Environmental Protection Agency, Washington, DC

[23] "NUREG-0324 - XOQDOQ, Program for the Meteorological Evaluation of Routine Effluent Releases at Nuclear Power Stations," Nuclear Regulatory Commission, September, 1977

[24] "10 CFR 20 - Standards for Protection Against Radiation," US Nuclear Regulatory Commission, Washington, DC

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

[26] "Limerick Generating Station Land Use Census," 2024

[27] "CY-LG-170-301 Limerick Generating Station Units 1 and 2 Offsite Dose Calculation Manual," Current Revision

[28] "Annual Environmental Quality Assurance Report for the Radiological Environmental Monitoring Program (REMP)," GEL, 2024

[29] "4th Quarter 2024 Quality Assurance Report," Teledyne Browne Engineering Environmental Services, January-December, 2024

[30] Landauer Incorporated, Proprietary Procedures, Current Revisions

[31] Normandeau Associates, Inc. (NAI) Sampling Procedures for Collection of Fish and Bottom Sediment for Radiological Analysis, Current Revisions

a. ER6 COLLECTION OF FISH SAMPLES FOR RADIOLOGICAL ANALYSIS

b. ER7 COLLECTION OF SEDIMENT SAMPLES FOR RADIOLOGICAL ANALYSIS

[32] GEL Laboratory Procedures, Current Revisions

a. GL-RAD-A-002 Tritium

b. GL-RAD-A-022 Ni-63

c. GL-RAD-A-004 Sr89/90, Liquid

d. GL-RAD-A-040 Fe-55

[33] Teledyne Browne Engineering (TBE), 2018 Analysis Procedures, Current Revisions

a. TBE-2001 Alpha Isotopic and Pu-241

b. TBE-2006 Iron-55 Activity in Various Matrices if needed

c. TBE-2007 Gamma Emitting Radioisotope Analysis

d. TBE-2008 Gross Alpha and/or Gross Beta Activity in Various Matrices

e. TBE-2011 Tritium Analysis in Drinking Water by Liquid Scintillation

f. TBE-2012 Radioiodine in Various Matrices

g. TBE-2013 Radionickel Activity in Various Matrices h.TBE-2018 Radiostrontium Analysis by Chemical Separation

[34] CY-AA-170-1000 Radiological Environmental Monitoring Program (REMP) and Meteorological Program Implementation, Current Revision

[35] GHD, Inc. Hydrogeologic Investigation Report, Limerick Generating Station, 3146 Sanatoga Road, Pottstown, Pennsylvania, Ref. No. 11189800(1), December, 2019 I

I I

Annual Radiological Environmental Operating Report YEAR: 2024 Page 39 of 82 Company: Constellation Plant: Limerick Generating Station

, Data Table Summary Medium or Pathway Sampled (Units)

Type, Total Number of Analyses performed (e.g., I-131, 400)

Lower Limit of Detection (LLD)

Indicator Mean1; (f2).

Range1 Location with Highest Annual Mean Control Mean1 (f2).

Range1 Number of Nonroutine Reported Measurements Name Distance and Direction Mean1 (f2)

Range1 Air Particulates (pCi/m3)

Gross Beta, (364) 1.0 2.12E-02 (312/312)

(5.73E 5.41E-02) 13S4, 1,186 feet SE 2.25E-02 (52/52)

(6.45E 4.02E-02) 1.90E-02 (52/52)

(6.52E 3.24E-02) 0 Direct Radiation (mrem/qtr.)

OSLD (320)

N/A 17.5 (312/312)

(11.1-26.4) 13S2, 2,149 feet SE 25.10 (8/8)

(23.7-26.4) 21.40 (8/8)

(18.1-25.2) 0 Surface Water (pCi/L)

Gross Beta (48) 4 3.04, (36/36)

(1.57-5.16) 15F4, 45,514 feet SE 3.39, (12/12)

(1.84-5.16) 2.95 (12/12)

(1.84-4.09) 0 1 Mean and range are based on detectable measurements only.

2 Fraction of detectable measurements at specified locations is indicated in parentheses.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 40 of 82 Company: Constellation Plant: Limerick Generating Station

, Complete Data Table for All Analysis Results Obtained In 2024 Table 10, Monthly Sample Results Monthly Radionuclides in Surface Water (pCi/L) 24S1 (Control) 13B1 Date Gamma Emitters Gross Beta Activity Uncertainty (2-)

Gamma Emitters Gross Beta Activity Uncertainty (2-)

1/29/2024 ND ND ND ND 3/4/2024 ND ND ND ND 4/1/2024 ND ND ND ND 4/29/2024 ND ND ND ND 6/3/2024 ND ND ND ND 7/1/2024 ND ND ND ND 7/29/2024 ND ND ND ND 9/3/2024 ND ND ND ND 9/30/2024 ND ND ND ND 10/28/2024 ND ND ND ND 12/2/2024 ND ND ND ND 12/30/2024 ND ND ND ND

Annual Radiological Environmental Operating Report YEAR: 2024 Page 41 of 82 Company: Constellation Plant: Limerick Generating Station Table 10, Monthly Sample Results Monthly Radionuclides in Drinking Water (pCi/L) 28F3 (Control) 16C2 15F4 15F7 Date Gamma Emitters Gross Beta Activity Uncertainty (2-)

Gamma Emitters Gross Beta Activity Uncertainty (2-)

1/29/2024 2.22E+00 8.28E-01 1.97E+00 8.20E-01 1.84E+00 8.05E-01 1.85E+00 8.01E-01 3/4/2024 1.84E+00 7.85E-01 1.76E+00 7.84E-01 1.85E+00 7.90E-01 1.70E+00 7.75E-01 4/1/2024 2.11E+00 8.03E-01 1.57E+00 7.70E-01 2.48E+00 8.29E-01 2.16E+00 8.03E-01 4/29/2024 1.91E+00 7.50E-01 1.65E+00 7.36E-01 2.16E+00 7.69E-01 1.80E+00 7.41E-01 6/3/2024 2.54E+00 8.04E-01 2.06E+00 7.72E-01 2.80E+00 8.23E-01 3.39E+00 8.62E-01 7/1/2024 3.22E+00 8.25E-01 2.84E+00 8.01E-01 3.92E+00 8.73E-01 3.81E+00 8.68E-01 7/29/2024 4.09E+00 9.14E-01 2.50E+00 8.10E-01 4.04E+00 9.10E-01 2.68E+00 8.76E-01 9/3/2024 2.85E+00 8.38E-01 2.70E+00 8.27E-01 3.64E+00 8.93E-01 3.59E+00 8.86E-01 9/30/2024 3.48E+00 8.19E-01 3.96E+00 8.51E-01 4.70E+00 9.02E-01 4.76E+00 9.06E-01 10/28/2024 3.88E+00 9.29E-01 3.74E+00 9.22E-01 4.29E+00 9.55E-01 4.60E+00 9.76E-01 12/2/2024 4.00E+00 9.56E-01 2.75E+00 8.76E-01 5.16E+00 1.02E+00 3.96E+00 9.52E-01 12/30/2024 3.24E+00 8.59E-01 3.78E+00 1.13E+00 3.81E+00 8.96E-01 3.27E+00 8.62E-01

Annual Radiological Environmental Operating Report YEAR: 2024 Page 42 of 82 Company: Constellation Plant: Limerick Generating Station Table 10, Monthly Sample Results Monthly Radionuclides in Milk (pCi/L)

Date 18E1 19B1 22B1 8G1 (Control) 1/17/2024 2/12/2024 2/13/2024 3/12/2024 4/2/2024 4/16/2024 4/30/2024 5/14/2024 5/28/2024 6/11/2024 6/25/2024 7/9/2024 7/23/2024 8/6/2024 8/20/2024 9/3/2024 9/16/2024 10/1/2024

Annual Radiological Environmental Operating Report YEAR: 2024 Page 43 of 82 Company: Constellation Plant: Limerick Generating Station Table 10, Monthly Sample Results Monthly Radionuclides in Milk (pCi/L)

Date 18E1 19B1 22B1 8G1 (Control) 10/14/2024 10/28/2024 11/12/2024 11/25/2024 12/10/2024

Annual Radiological Environmental Operating Report YEAR: 2024 Page 44 of 82 Company: Constellation Plant: Limerick Generating Station Table 10, Monthly Sample Results Monthly Radionuclides in Vegetation (pCi/kg wet)

Sample Date Sample Code Sample Type Gamma Emitters 6/18/2024 11S3 ESE Sector at retired LGS Information Center Horseradish 6/18/2024 Broccoli 6/18/2024 Collards 7/16/2024 Cabbage 7/16/2024 Broccoli 7/16/2024 Cauliflower 8/13/2024 Cabbage 8/13/2024 Kale 8/13/2024 Collards 9/10/2024 Collards 9/10/2024 Kale 9/10/2024 Horseradish

Annual Radiological Environmental Operating Report YEAR: 2024 Page 45 of 82 Company: Constellation Plant: Limerick Generating Station Table 10, Monthly Sample Results Monthly Radionuclides in Vegetation (pCi/kg wet)

Sample Date Sample Code Sample Type Gamma Emitters 6/18/2024 13S3 SE Sector along Longview Road at the 500Kv substation Collards 6/18/2024 Lettuce 6/18/2024 Horseradish 7/16/2024 Collards 7/16/2024 Cabbage 7/16/2024 Broccoli 8/13/2024 Cabbage 8/13/2024 Collards 8/13/2024 Kale 9/10/2024 Collards 9/10/2024 Horseradish 9/10/2024 Kale

Annual Radiological Environmental Operating Report YEAR: 2024 Page 46 of 82 Company: Constellation Plant: Limerick Generating Station Table 10, Monthly Sample Results Monthly Radionuclides in Vegetation (pCi/kg wet)

Sample Date Sample Code Sample Type Gamma Emitters 6/18/2024 31G1 (Control)

NW sector, Jollyview Farm Broccoli 6/18/2024 Cauliflower 6/18/2024 Kale 7/16/2024 Rhubarb 7/16/2024 Cabbage 7/16/2024 Squash 8/13/2024 Rhubarb 8/13/2024 Cabbage 8/13/2024 Squash 9/10/2024 Squash 9/10/2024 Collards 9/10/2024 Rhubarb

All Non-Natural Radionuclides <MDA ND - No Data, Sample collected as required.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 47 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for I-131 (pCi/m3)

Date 6C1 10S3 11S1 14S1 13S4 15D1 22G1 (Control) 1/8/2024 1/16/2024 1/22/2024 1/29/2024 2/6/2024 2/12/2024 2/19/2024 2/26/2024 3/4/2024 3/11/2024 3/18/2024 3/25/2024 4/1/2024 4/8/2024 4/15/2024 4/22/2024 4/29/2024 5/6/2024 5/13/2024 5/20/2024 5/28/2024

Annual Radiological Environmental Operating Report YEAR: 2024 Page 48 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for I-131 (pCi/m3)

Date 6C1 10S3 11S1 14S1 13S4 15D1 22G1 (Control) 6/3/2024 6/10/2024 6/17/2024 6/25/2024 7/1/2024 7/8/2024 7/15/2024 7/22/2024 7/29/2024 8/5/2024 8/12/2024 8/19/2024 8/26/2024 9/3/2024 9/9/2024 9/16/2024 9/23/2024 9/30/2024 10/7/2024 10/14/2024

Annual Radiological Environmental Operating Report YEAR: 2024 Page 49 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for I-131 (pCi/m3) 10/21/2024 10/29/2024 11/4/2024 11/11/2024 11/18/2024 11/25/2024 12/2/2024 12/9/2024 12/16/2024 12/23/2024 12/30/2024

<MDA, Minimum Detectable Activity

Annual Radiological Environmental Operating Report YEAR: 2024 Page 50 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for Gross Beta activity in Air Particulates (pCi/m3) 6C1 10S3 11S1 14S1 13S4 15D1 22G1 (Control)

Date Gross Beta Activity (2-)

Gross Beta Activity (2-)

1/8/2024 1.21E-02 2.02E-03 1.67E-02 2.20E-03 1.50E-02 2.13E-03 1.42E-02 2.09E-03 1.39E-02 2.08E-03 1.60E-02 2.17E-03 1.46E-02 2.12E-03 1/16/2024 2.72E-02 2.08E-03 2.47E-02 2.01E-03 2.74E-02 2.13E-03 2.34E-02 1.98E-03 1.94E-02 1.84E-03 2.84E-02 2.13E-03 2.00E-02 1.83E-03 1/22/2024 3.12E-02 2.66E-03 2.65E-02 2.51E-03 2.86E-02 2.57E-03 2.62E-02 2.49E-03 3.31E-02 2.73E-03 3.02E-02 2.60E-03 2.66E-02 2.55E-03 1/29/2024 1.79E-02 1.98E-03 1.56E-02 1.90E-03 1.72E-02 1.96E-03 1.50E-02 1.87E-03 1.35E-02 1.81E-03 1.68E-02 1.96E-03 1.30E-02 1.78E-03 2/6/2024 1.62E-02 1.81E-03 1.55E-02 1.78E-03 1.44E-02 1.75E-03 1.32E-02 1.70E-03 1.45E-02 1.75E-03 1.57E-02 1.78E-03 1.44E-02 1.73E-03 2/12/2024 2.02E-02 2.33E-03 2.14E-02 2.37E-03 1.94E-02 2.30E-03 1.88E-02 2.29E-03 2.12E-02 2.36E-03 2.00E-02 2.35E-03 1.84E-02 2.34E-03 2/19/2024 2.50E-02 2.22E-03 2.39E-02 2.19E-03 2.27E-02 2.15E-03 2.05E-02 2.07E-03 2.44E-02 2.20E-03 2.21E-02 2.15E-03 1.95E-02 2.00E-03 2/26/2024 2.13E-02 2.12E-03 2.07E-02 2.10E-03 2.20E-02 2.14E-03 2.02E-02 2.08E-03 2.33E-02 2.19E-03 2.10E-02 2.11E-03 1.86E-02 2.02E-03 3/4/2024 2.26E-02 2.13E-03 2.15E-02 2.10E-03 2.09E-02 2.08E-03 1.93E-02 2.02E-03 2.28E-02 2.14E-03 2.08E-02 2.08E-03 2.00E-02 2.06E-03 3/11/2024 7.76E-03 1.60E-03 6.89E-03 1.56E-03 5.73E-03 1.50E-03 6.17E-03 1.53E-03 6.45E-03 1.54E-03 6.89E-03 1.56E-03 6.52E-03 1.54E-03 3/18/2024 2.88E-02 2.35E-03 2.74E-02 2.31E-03 2.93E-02 2.37E-03 2.85E-02 2.34E-03 2.90E-02 2.36E-03 2.89E-02 2.35E-03 2.75E-02 2.31E-03 3/25/2024 1.41E-02 1.91E-03 1.56E-02 1.96E-03 1.14E-02 1.80E-03 1.26E-02 1.85E-03 1.35E-02 1.88E-03 1.44E-02 1.92E-03 1.32E-02 1.90E-03 4/1/2024 1.83E-02 1.95E-03 2.13E-02 2.06E-03 1.81E-02 1.94E-03 1.65E-02 1.88E-03 1.99E-02 2.01E-03 1.97E-02 2.00E-03 1.77E-02 1.90E-03 4/8/2024 9.30E-03 1.55E-03 7.86E-03 1.48E-03 1.07E-02 1.62E-03 7.86E-03 1.48E-03 9.66E-03 1.57E-03 9.26E-03 1.55E-03 7.54E-03 1.47E-03 4/15/2024 1.96E-02 2.03E-03 1.85E-02 1.99E-03 1.84E-02 1.98E-03 1.66E-02 1.92E-03 1.76E-02 1.96E-03 1.87E-02 2.00E-03 1.72E-02 1.94E-03

Annual Radiological Environmental Operating Report YEAR: 2024 Page 51 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for Gross Beta activity in Air Particulates (pCi/m3) 6C1 10S3 11S1 14S1 13S4 15D1 22G1 (Control)

Date Gross Beta Activity (2-)

Gross Beta Activity (2-)

4/22/2024 1.68E-02 1.97E-03 1.68E-02 1.97E-03 1.60E-02 1.94E-03 1.42E-02 1.87E-03 1.73E-02 1.99E-03 1.75E-02 2.00E-03 1.59E-02 1.94E-03 4/29/2024 2.36E-02 2.24E-03 1.99E-02 2.12E-03 1.93E-02 2.10E-03 1.88E-02 2.09E-03 2.15E-02 2.18E-03 1.98E-02 2.13E-03 1.97E-02 2.16E-03 5/6/2024 1.79E-02 2.04E-03 1.79E-02 2.04E-03 1.64E-02 1.98E-03 1.42E-02 1.89E-03 1.82E-02 2.04E-03 1.87E-02 2.05E-03 1.46E-02 1.87E-03 5/13/2024 1.22E-02 1.79E-03 1.11E-02 1.75E-03 1.17E-02 1.77E-03 7.80E-03 1.60E-03 1.25E-02 1.80E-03 1.25E-02 1.80E-03 1.07E-02 1.73E-03 5/20/2024 1.46E-02 1.91E-03 1.54E-02 1.94E-03 1.53E-02 1.94E-03 1.23E-02 1.83E-03 1.47E-02 1.91E-03 1.37E-02 1.88E-03 1.35E-02 1.91E-03 5/28/2024 2.23E-02 1.92E-03 2.05E-02 1.86E-03 2.13E-02 1.89E-03 1.97E-02 1.83E-03 2.28E-02 1.94E-03 2.14E-02 1.89E-03 2.07E-02 1.88E-03 6/3/2024 2.04E-02 2.29E-03 1.89E-02 2.23E-03 2.01E-02 2.28E-03 1.84E-02 2.22E-03 2.08E-02 2.31E-03 2.10E-02 2.31E-03 1.76E-02 2.13E-03 6/10/2024 2.31E-02 2.16E-03 1.87E-02 2.01E-03 2.13E-02 2.10E-03 1.69E-02 1.94E-03 2.27E-02 2.15E-03 2.14E-02 2.10E-03 1.87E-02 2.04E-03 6/17/2024 1.82E-02 2.01E-03 1.94E-02 2.06E-03 1.66E-02 1.95E-03 1.55E-02 1.91E-03 1.86E-02 2.03E-03 1.81E-02 2.01E-03 1.60E-02 1.93E-03 6/25/2024 2.60E-02 2.05E-03 2.75E-02 2.10E-03 2.67E-02 2.08E-03 2.19E-02 1.93E-03 2.50E-02 1.94E-03 2.56E-02 2.05E-03 2.22E-02 1.95E-03 7/1/2024 1.74E-02 2.16E-03 1.79E-02 2.18E-03 1.59E-02 2.09E-03 1.52E-02 2.07E-03 1.91E-02 2.23E-03 2.03E-02 2.26E-03 1.79E-02 2.16E-03 7/8/2024 2.13E-02 2.09E-03 2.01E-02 2.05E-03 1.88E-02 2.01E-03 1.71E-02 1.95E-03 2.15E-02 2.11E-03 2.09E-02 2.09E-03 2.00E-02 2.06E-03 7/15/2024 2.02E-02 2.12E-03 1.96E-02 2.10E-03 1.95E-02 2.09E-03 1.57E-02 1.96E-03 2.15E-02 2.16E-03 1.88E-02 2.07E-03 1.82E-02 2.05E-03 7/22/2024 2.39E-02 2.23E-03 2.54E-02 2.29E-03 2.50E-02 2.27E-03 2.08E-02 2.13E-03 2.95E-02 2.41E-03 2.54E-02 2.30E-03 2.03E-02 2.34E-03 7/29/2024 2.09E-02 2.10E-03 2.09E-02 2.10E-03 1.98E-02 2.06E-03 1.89E-02 2.03E-03 2.13E-02 2.12E-03 2.19E-02 2.14E-03 1.91E-02 2.04E-03

Annual Radiological Environmental Operating Report YEAR: 2024 Page 52 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for Gross Beta activity in Air Particulates (pCi/m3) 6C1 10S3 11S1 14S1 13S4 15D1 22G1 (Control)

Date Gross Beta Activity (2-)

Gross Beta Activity (2-)

8/5/2024 2.77E-02 2.34E-03 2.75E-02 2.34E-03 2.56E-02 2.28E-03 2.17E-02 2.15E-03 3.03E-02 2.43E-03 2.89E-02 2.39E-03 2.47E-02 2.25E-03 8/12/2024 1.76E-02 2.02E-03 1.76E-02 2.02E-03 1.69E-02 1.99E-03 1.63E-02 1.97E-03 2.11E-02 2.14E-03 1.91E-02 2.07E-03 1.72E-02 1.98E-03 8/19/2024 2.28E-02 2.18E-03 2.42E-02 2.23E-03 2.30E-02 2.19E-03 2.02E-02 2.10E-03 2.45E-02 2.24E-03 2.12E-02 2.13E-03 2.02E-02 2.12E-03 8/26/2024 1.96E-02 2.07E-03 1.91E-02 2.08E-03 2.00E-02 2.11E-03 1.60E-02 1.97E-03 2.17E-02 2.17E-03 1.86E-02 2.06E-03 1.63E-02 1.99E-03 9/3/2024 3.02E-02 2.27E-03 3.91E-02 2.46E-03 3.63E-02 2.39E-03 2.67E-02 2.12E-03 3.13E-02 2.25E-03 3.29E-02 2.30E-03 2.90E-02 2.16E-03 9/9/2024 1.41E-02 2.08E-03 1.54E-02 2.17E-03 1.38E-02 2.10E-03 1.52E-02 2.16E-03 1.61E-02 2.20E-03 1.58E-02 2.18E-03 1.41E-02 2.12E-03 9/16/2024 3.52E-02 2.61E-03 3.16E-02 2.48E-03 3.20E-02 2.49E-03 3.01E-02 2.43E-03 3.73E-02 2.64E-03 3.39E-02 2.54E-03 2.96E-02 2.38E-03 9/23/2024 3.24E-02 2.41E-03 2.80E-02 2.31E-03 2.73E-02 2.29E-03 2.47E-02 2.20E-03 3.27E-02 2.45E-03 2.92E-02 2.35E-03 2.44E-02 2.23E-03 9/30/2024 1.11E-02 1.71E-03 8.68E-03 1.61E-03 9.12E-03 1.63E-03 8.96E-03 1.62E-03 1.10E-02 1.71E-03 1.10E-02 1.71E-03 6.56E-03 1.51E-03 10/7/2024 2.05E-02 2.08E-03 2.15E-02 2.12E-03 2.04E-02 2.08E-03 1.82E-02 2.00E-03 2.35E-02 2.18E-03 2.14E-02 2.12E-03 1.83E-02 2.01E-03 10/14/2024 3.30E-02 2.50E-03 4.80E-02 2.87E-03 4.27E-02 2.73E-03 3.29E-02 2.45E-03 3.59E-02 2.54E-03 4.11E-02 2.69E-03 3.24E-02 2.40E-03 10/21/2024 2.19E-02 2.08E-03 1.60E-02 1.89E-03 1.84E-02 1.99E-03 1.65E-02 1.91E-03 2.18E-02 2.10E-03 1.90E-02 2.00E-03 1.62E-02 1.93E-03 10/29/2024 3.26E-02 2.32E-03 3.04E-02 2.27E-03 2.97E-02 2.25E-03 3.00E-02 2.25E-03 3.63E-02 2.43E-03 3.23E-02 2.32E-03 3.05E-02 2.27E-03 11/4/2024 4.00E-02 2.94E-03 5.41E-02 3.31E-03 4.41E-02 3.05E-03 3.92E-02 2.91E-03 4.02E-02 2.94E-03 4.16E-02 2.99E-03 3.21E-02 2.71E-03 11/11/2024 2.02E-02 2.09E-03 2.08E-02 2.11E-03 2.04E-02 2.10E-03 1.60E-02 1.94E-03 2.35E-02 2.20E-03 2.10E-02 2.13E-03 1.91E-02 2.05E-03

Annual Radiological Environmental Operating Report YEAR: 2024 Page 53 of 82 Company: Constellation Plant: Limerick Generating Station Table 11, Weekly Airborne Samples Weekly Airborne Samples for Gross Beta activity in Air Particulates (pCi/m3) 6C1 10S3 11S1 14S1 13S4 15D1 22G1 (Control)

Date Gross Beta Activity (2-)

Gross Beta Activity (2-)

11/18/2024 1.80E-02 2.05E-03 1.83E-02 2.06E-03 1.63E-02 1.99E-03 1.40E-02 1.90E-03 1.97E-02 2.11E-03 1.91E-02 2.09E-03 1.43E-02 1.92E-03 11/25/2024 2.63E-02 2.22E-03 2.47E-02 2.17E-03 2.31E-02 2.11E-03 2.15E-02 2.06E-03 2.73E-02 2.25E-03 2.74E-02 2.25E-03 2.56E-02 2.17E-03 12/2/2024 2.95E-02 2.40E-03 2.68E-02 2.31E-03 2.62E-02 2.29E-03 2.35E-02 2.21E-03 3.16E-02 2.46E-03 3.30E-02 2.50E-03 2.71E-02 2.36E-03 12/9/2024 2.22E-02 2.20E-03 2.10E-02 2.16E-03 2.19E-02 2.19E-03 1.91E-02 2.09E-03 2.43E-02 2.27E-03 2.16E-02 2.18E-03 2.07E-02 2.12E-03 12/16/2024 2.49E-02 2.20E-03 2.87E-02 2.32E-03 2.65E-02 2.25E-03 2.23E-02 2.11E-03 3.09E-02 2.39E-03 3.03E-02 2.37E-03 2.20E-02 2.10E-03 12/23/2024 1.46E-02 1.86E-03 1.62E-02 1.94E-03 1.31E-02 1.82E-03 1.45E-02 1.87E-03 1.68E-02 1.95E-03 1.49E-02 1.87E-03 1.33E-02 1.84E-03 12/30/2024 1.88E-02 2.02E-03 2.03E-02 2.06E-03 1.88E-02 2.01E-03 1.75E-02 1.97E-03 2.34E-02 2.17E-03 2.00E-02 2.07E-03 1.51E-02 1.88E-03

Annual Radiological Environmental Operating Report YEAR: 2024 Page 54 of 82 Company: Constellation Plant: Limerick Generating Station Table 12, Quarterly isotopic data - Air (pCi/m3), Water (pCi/L)

Location Nuclide Q1 Q2 Q3 Q4 Quarterly Air Filter Composite for Gamma Emitters (pCi/m3) 6C1 Cs134, Cs137

<MDAs

<MDAs 10S3 Cs134, Cs137

<MDAs

<MDAs 11S1 Cs134, Cs137

<MDAs

<MDAs 14S1 Cs134, Cs137

<MDAs

<MDAs 15D1 Cs134, Cs137

<MDAs

<MDAs 22G1 (Control)

Cs134, Cs137

<MDAs

<MDAs 13S4 Cs134, Cs137

<MDAs

<MDAs Quarterly Tritium in Water (pCi/L) 24S1 H-3

<MDA

<MDA 13B1 H-3

<MDA

<MDA 28F3 H-3

<MDA

<MDA 16C2 H-3

<MDA

<MDA 15F4 H-3

<MDA

<MDA 15F7 H-3

<MDA

All Non-Natural Gamma Emitters <MDA

Annual Radiological Environmental Operating Report YEAR: 2024 Page 55 of 82 Company: Constellation Plant: Limerick Generating Station Table 13, Complete REMP Results Radionuclides in Fish (pCi/kg wet)

Sample Code Sample Date Sample Type Gamma Emitters 29C1 BKG (Control)

Area not influenced by Plant Discharge 05/2/2024 Bottom Feeder 05/2/2024 Predator Fish 10/9/2024 Bottom Feeder 10/9/2024 Predator Fish 16C5 IND LGS Discharge Area 05/30/2024 Bottom Feeder 05/30/2024 Predator Fish 10/10/2024 Bottom Feeder 10/10/2024 Predator Fish Radionuclides in Sediment (pCi/kg dry)

Sample Code Sample Date Gamma Emitters 16C4 SSE Sector, Down River from Plant Discharge Area 06/7/2024 11/15/2024 16B2 SSE Sector, Down River from Plant Discharge Area 06/7/2024 11/15/2024 33A2 (Control)

NNW Sector, Upstream from Plant Discharge Area 06/7/2024 11/15/2024

All Non-Natural Gamma Emitters <MDA

Annual Radiological Environmental Operating Report YEAR: 2024 Page 56 of 82 Company: Constellation Plant: Limerick Generating Station Table 13, Complete REMP Results Complete RGPP Results (pCi/L +/- 2-)

Location Sample Date Gross Alpha (dissolved)

Gross Alpha (suspended)

Sr89 Sr90 Gamma Emitters*

Qualifier DW-LR-1 4/9/2024 5.08+/-5.2

<0.876

<4.46

<0.852

<MDA DW-LR-1 5/3/2024 4.64+/-1.45

<0.696 ND ND ND Resample MW-LR-1 4/10/2024

<0.923

<1.1

<7.09

<0.897

<MDA MW-LR-2 4/10/2024 ND ND ND ND

<MDA MW-LR-3 4/10/2024 ND ND ND ND

<MDA MW-LR-4 4/9/2024

<1.44

<1.09

<2.97

<0.880

<MDA MW-LR-5 4/10/2024 ND ND ND ND

<MDA Dup MW-LR-5 4/10/2024 ND ND ND ND

<MDA QA MW-LR-7 4/10/2024 ND ND ND ND

<MDA MW-LR-8 4/9/2024 1.65+/-0.973

<0.878

<2.68

<0.869

<MDA MW-LR-9 4/9/2024 2.5 +/-1.16 4.32+/-1.61

<3.93

<0.905

<MDA MW-LR-9 4/9/2024

<1.45 2.17+/-1.33

<4.65

<0.948

<MDA Dup MW-LR-9 4/9/2024

<7.08 ND

<1.09

<0.819

<MDA QA MW-LR-10 4/9/2024 1.75+/-0.991

<0.878

<3.61

<0.753

<MDA P11 4/9/2024

<1.38

<0.88

<5.45

<0.95

<MDA P14 4/9/2024

<1.33

<0.906

<3.51

<0.958

<MDA P17 4/10/2024 ND ND ND ND

<MDA ND - No Data, Sample collected as required.

(Dup) - Sample analyzed in duplicate by TBE.

(QA) - Additional sample collected and analyzed for Quality Assurance by GEL.

All non-natural gamma emitters less than minimum detectable activity.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 57 of 82 Company: Constellation Plant: Limerick Generating Station Table 13, Complete REMP Results Concentration of Tritium in Groundwater (pCi/L +/- 2)

Location Q1 Q2 Q3 Q4 DW-LR-1

<194

<192

<172

<186 MW-LR-1 ND

<193 ND ND MW-LR-2 ND

<198 ND ND MW-LR-3 ND

<193 ND ND MW-LR-4

<194

<187

<184 MW-LR-4 (Dup)

ND ND

<186 ND MW-LR-4 (QA)

ND ND

<169 ND MW-LR-5 ND

<194 ND ND MW-LR-5 (Dup)

ND

<195 ND ND MW-LR-5 (QA)

ND

<97.7 ND ND MW-LR-7 ND

<193 ND ND MW-LR-8 480+/-131 765+/-159 1330+/-217 / 721+/-155 430+/-132 MW-LR-8 (Dup)

ND ND 727+/-160 /ND ND MW-LR-9 3580+/-423 3000+/-372 2650+/-338 1810+/-253 MW-LR-9(Dup) 3400+/-403 2740+/-346 No Data 1920+/-262 MW-LR-9 (QA) 3270+/-283 2370+/-228

+/-

1880+/-144 MW-LR-10

<186

<184

<191

<182 LR-P11

<196

<178

<190

<186 LR-P14

<189

<196

<190

<184 LR-P17 ND

<197 ND ND ND - No Data, Sample collected as required.

(Dup) - Sample analyzed in duplicate by TBE.

(QA) - Additional sample collected and analyzed for Quality Assurance by GEL.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 58 of 82 Company: Constellation Plant: Limerick Generating Station Table 13, Complete REMP Results Concentration of Tritium in Recapture Samples (pCi/L +/- 2)

LOCATION 1/18/2024 8/26/2024 RS-1

<195

<185 RS-2 288+/-134

<188 RS-3 516+/-141

<186 RS-4 214+/-130

<186 RS-5 226+/-130

<185 RS-6 235+/-131

<188 RS-7 244+/-132

<186 RS-8

<187

<188

Annual Radiological Environmental Operating Report YEAR: 2024 Page 59 of 82 Company: Constellation Plant: Limerick Generating Station

, Cross Check Intercomparison Program Participation in cross check intercomparison studies is mandatory for laboratories performing analyses of REMP samples satisfying the requirements in the ODCM. Intercomparison studies provide a consistent and effective means to evaluate the accuracy and precision of analyses performed by a laboratory. Study results should fall within specified control limits and results that fall outside the control limits are investigated and corrected.

Constellation Generation Solutions Laboratory participated in the following proficiency testing studies provided by Environmental Resource Associates (ERA) and Eckert Ziegler Analytics (EZA) in 2024. The Laboratorys intercomparison program results for 2024 are summarized below. is a summary of Constellation Generation Solutions (CGS) laboratorys quality assurance program. It consists of Table 14, which is a compilation of the results of the CGS laboratorys participation in an interlaboratory comparison program with Environmental Resource Associates (ERA) located in Arvada, Colorado and Eckert and Ziegler Analytics, Inc. (EZA) located in Atlanta, Georgia.

It also includes a compilation of the results of the Constellation Generation Solutions (CGS) Laboratorys participation in a split sample program with Teledyne Brown Engineering located in Knoxville, Tennessee.

The CGS laboratory's intercomparison results are in full agreement when they were evaluated using designated acceptance ranges and the Resolution Test Criteria in accordance with the Constellation Radiochemistry Quality Control procedure, except as noted in the Pass/Fail column and described below. The CGS laboratory's results are provided with their analytical uncertainties of 2 sigma. When evaluating with the Resolution Test, a one sigma uncertainty is used to determine Pass or Fail and noted accordingly.

All results reported passed their respective acceptance ranges and Resolution Test Criteria with the following two exceptions:

RAD-137 I-131 water study on 04/08/2024 on Detector 6 (D6) failed high at 29.7 pCi/L for a true value of 25.1 pCi/L with an acceptance range of 21.7 - 28.5 pCi/L. This was a new detector and the study had very low area counts. Of the three runs, the other two values would have passed. Results on all other detectors were successful. Further review of the data indicated all the Ba-133 results in the other RAD-137 water study were in acceptable range. In that study, Ba-133 is meant to approximate I-131 results as it has an energy very close to I-131 in the spectrum. The detector is new in the lab and there is an ongoing review of its performance to identify the optimal operating range and any inherent bias.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 60 of 82 Company: Constellation Plant: Limerick Generating Station E14044 Filter study on 12/05/24 failed low for Cs-134 on D6 reporting 91.3 +/- 3.25 pCi for a true value of 116 pCi. This study also had unusually low area counts in this range of the spectrum. The result did pass the acceptance range of 81.2 - 150.8 pCi, however due to the extremely low activity level, count times were extended significantly to capture other isotopes with lower yields resulting in very low uncertainties for higher yield isotopes. In the case of Cs-134 the uncertainty was less than 5% and at the level of recovery observed, the result failed the resolution test. Routine analysis is normally performed to achieve 15% +/- 5 %. Review of all other studies performed on this detector showed successful performance for Cs-134 and all other isotopes. The evaluation of detector performance is ongoing to identify inherent bias or variability at low count rates as is observed in environmental samples.

The vendor laboratories used by CGS for subcontracting and interlaboratory comparison samples, GEL Laboratories and Teledyne Brown Engineering (TBE), also participate in the ERA and EZA interlaboratory comparison program. A presentation of their full data report is provided in their Annual Environmental Quality Assurance Program Reports, (Ref 42,43). In summary, GEL and TBE reported results met vendor and laboratory acceptance ranges with the following exceptions described here.

For TBE, the following three studies reported data that did not meet the specified acceptance criteria and were addressed through the TBE Corrective Action Program. Investigations of the failures are described as follows:

TBE Crosschecks failed high for MRAD-40 Gross Beta at 42.1 pCi/Filter. The true value was 22.2 pCi/Filter and the acceptable range was 13.5-33.5 pCi/Filter. All QC associated with the original sample was acceptable and no anomalies were found. This sample was used as the WG duplicate with a result of 42.5 pCi. Both samples were counted on the same detector. Upon comparison to historical sample data, the alpha activity of this ERA submitted sample was the highest assigned result, and the beta activity was the lowest. Therefore, the alpha-to-beta crosstalk was more significant than normal, causing the beta activity to report falsely high data. The counting room laboratory staff will adjust the alpha-to-beta crosstalk via correction calculation measures when high alpha are observed. Subsequent study MRAD-41 for Gross Beta filter returned acceptable results.

RAD-137 Gross Alpha in water failed low at 35.2 pCi/L. The true value was 52.6 pCi/L and the acceptable range was 39.6 - 65.6 pCi/L. A QuiKResponse repeat study was analyzed and failed high at 40.3 pCi/L and the acceptable range was 21.5 - 38.5 pCi/L. Investigation showed higher than usual solids in the ERA study, out of the usual range of client samples received by the lab. Also, a different attenuation curve, Th-230, was used for the crosscheck than had been used historically. This curve was less representative of client samples.

The lab review of data also showed that a replicate run of the sample would have passed but the lab chose the wrong replicate to report. The lab has gone to a lower volume of sample and resumed using the Am-241

Annual Radiological Environmental Operating Report YEAR: 2024 Page 61 of 82 Company: Constellation Plant: Limerick Generating Station attenuation curve which more closely mirrors client samples and subsequent crosschecks are reporting acceptable.

Quarter 1-2024 gamma results for Co-60 (air filter) and Ce-141 (soil) both failed high. The reported result for the filter for Co-60 was 168+/- 12.7 pCi/Filter and the known value was 126+/-2.1 pCi/Filter; the reported results for the soil Ce-141 was 0.106 pCi/g and the known value was 0.0714+/- 0.0013 pCi/g. The root cause investigation showed successful results for the filter on another detector. All QC associated with this sample was acceptable. The soil was recounted on another detector and Ce-141 result of 0.085 was acceptable and generally the same for other geometries. All QC associated with this sample was acceptable. No effective corrective action can be taken at this time. Historically, the result for the filter for Co-60 and the result for the soil for Ce-141 have been well within TBE QC acceptance ranges. TBE has successfully passed cross-check results and it appears that these two results are anomalous. If there is a recurrence, a root cause investigation will be done promptly.

For the GEL Laboratory, the following six studies reported data that did not meet the specified acceptance criteria and were addressed through the GELs internal nonconformance system. A summary is found below:

RAD-136 water Sr-90 failed high, while I-131 failed low.

RAD-136 water Strontium-90: The Group Leader has reviewed the method to identify the bias. The method LCS trend was reviewed and no anomalies were identified. The calibration used for the analysis was compared to the new calibration performed recently and the original reported data was processed with both calibrations for comparison. Data still maintained a high bias but was within the limits of the study. A sample of known Strontium concentration was analyzed, and the results were processed using the new calibration. The result was within the mid-range of the acceptance limits. Instrument run logs were reviewed and there was no indication of possible bias from a previously counted sample.

RAD-136 water Iodine-131: The laboratory has reviewed the data and found no errors. All batch QC samples, including a duplicate, met acceptance criteria. The carrier yields were found to be slightly higher than typically seen in this method, possibly contributing to the low bias in the result. The laboratory will continue to investigate all steps of the analytical process.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 62 of 82 Company: Constellation Plant: Limerick Generating Station RAD-137 water Sr-90 and I-131 studies both failed low.

RAD-137 water Strontium-90: The unacceptable result was analyzed by a modified method of 905.0 and recovered 83% of the known value which is acceptable for the laboratorys LCS. The PT sample was also analyzed by EPA DW method 905.0 and achieved an acceptable result recovering 94% of the assigned value.

The RPD between the methods was 12%. The laboratory is evaluating calibration, yield determination, techniques, reagents, carriers, and each step of the process for areas of improvement.

RAD-137 water Iodine-131: The laboratory has reviewed the data and no errors were noted. All batch QC samples, including an in-batch duplicate, met acceptance criteria. It was noted that the carrier yields were found to be slightly higher than are typically seen in this method including the reference sample used to calculate the LCS, potentially contributing to the low bias in the result.

RAD-138 Sr-90 and I-131 on water failed low.

Strontium-90: The laboratory conducted an in-depth review of all available data and did not identify any specific errors or anomalies that could explain the performance evaluation failure. The instrument calibrations were reviewed for possible significant areas of variance when compared to previous calibrations and none were noted. The quality department conducted direct observations of the analytical processes noting minor areas of improvement during precipitations and column separations. A definitive root cause was not isolated during the investigation.

Iodine-131: The laboratory has reviewed the data and found no errors. All batch QC samples, including an in-batch duplicate, met the acceptance criteria. As part of the investigation, the quality department observed the preparation process. During the review, it was identified that a reagent may have been improperly diluted, potentially contributing to the low bias observed in the results. This procedural discrepancy has been noted as a probable cause requiring corrective action.

The laboratory has since successfully completed a single-blind spiked sample, achieving results within the acceptance criteria for both Sr-90 and I-131.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 63 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 3/14/2024 E14036 Milk pCi/L I-131 96.7 90.8 63.6 118 Pass pCi/L Cs-134 182 198 139 257 Pass pCi/L Cs-137 181 171 120 222 Pass pCi/L Ce-141 88.1 85 59.5 111 Pass pCi/L Cr-51 281 230 161 299 Pass pCi/L Mn-54 187 183 128 238 Pass pCi/L Fe-59 93.6 86.5 60.6 112 Pass pCi/L Co-60 152 158 111 205 Pass pCi/L Zn-65 161 176 123 229 Pass 3/14/2024 E14037 Water pCi/L Beta Cs-137 238 231 162 300 Pass 3/14/2024 E14038 Charcoal pCi I-131 75.9 90.2 63.1 117 Pass pCi I-131 79.0 90.2 63.1 117 Pass pCi I-131 77.1 90.2 63.1 117 Pass pCi I-131 77.3 90.2 63.1 117 Pass 4/8/2024 RAD-137 Water pCi/L I-131 27.1 25.1 21.7 28.5 Pass pCi/L I-131 25.1 25.1 21.7 28.5 Pass pCi/L I-131 27.5 25.1 21.7 28.5 Pass 4/8/2024 RAD-137 Water pCi/L I-131 29.7 25.1 21.7 28.5 Fail 1

Annual Radiological Environmental Operating Report YEAR: 2024 Page 64 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 4/8/2024 RAD-137 Water pCi/L Beta Cs-137 36.6 46.5 33.9 59.1 Pass pCi/L Cs-134 55.9 57.8 42.8 72.8 Pass pCi/L Cs-137 190 186 149 223 Pass pCi/L Co-60 98.8 98.8 79.7 118 Pass pCi/L Zn-65 228 240 188 292 Pass 4/8/2024 RAD-137 Water pCi/L Cs-134 60.7 57.8 42.8 72.8 Pass pCi/L Cs-137 185 186 149 223 Pass pCi/L Co-60 97.7 98.8 79.7 118 Pass pCi/L Zn-65 233 240 188 292 Pass 4/8/2024 RAD-137 Water pCi/L Cs-134 59.8 57.8 42.8 72.8 Pass pCi/L Cs-137 190 186 149 223 Pass pCi/L Co-60 97.2 98.8 79.7 118 Pass pCi/L Zn-65 240 240 188 292 Pass 4/8/2024 RAD-137 Water pCi/L Cs-134 58.6 57.8 42.8 72.8 Pass pCi/L Cs-137 185 186 149 223 Pass 4/8/2024 RAD-137 Water pCi/L Co-60 102 98.8 79.7 118 Pass pCi/L Zn-65 227 240 188 292 Pass 6/13/2024 E14101 Soil pCi/g Cs-134 0.406 0.408 0.286 0.530 Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 65 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 6/13/2024 E14101 Soil pCi/g Cs-137 0.402 0.451 0.316 0.586 Pass pCi/g Cs-134 0.372 0.408 0.286 0.530 Pass pCi/g Cs-137 0.365 0.451 0.316 0.586 Pass 6/13/2024 E14039 Water pCi/L Beta Cs-137 265 262 183 341 Pass 6/13/2024 E14040 pCi/L Ce-141 45.4 37.5 26.3 48.8 Pass pCi/L Co-60 402 391 274 508 Pass pCi/L Cr-51 250 291 204 378 Pass pCi/L Cs-134 237 242 169 315 Pass pCi/L Cs-137 233 229 160 298 Pass pCi/L Fe-59 183 174 122 226 Pass pCi/L Mn-54 209 204 143 265 Pass pCi/L Zn-65 89.6 99.1 69.4 129 Pass 6/13/2024 E14040 pCi/L Ce-141 40 37.5 26.3 48.8 Pass pCi/L Co-60 397 391 274 508 Pass pCi/L Cr-51 286 291 204 378 Pass pCi/L Cs-134 238 242 169 315 Pass pCi/L Cs-137 237 229 160 298 Pass pCi/L Fe-59 183 174 122 226 Pass pCi/L Mn-54 212 204 143 265 Pass pCi/L Zn-65 95.4 99.1 69.4 129 Pass 6/13/2024 E14041 Filter pCi Ce-141 25.4 25.2 17.6 32.8 Pass pCi Co-60 258 262 183 341 Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 66 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 6/13/2024 E14041 Filter pCi Cr-51 211 195 137 254 Pass pCi Cs-134 137 162 113 211 Pass pCi Cs-137 159 153 107 199 Pass pCi Fe-59 132 117 81.9 152 Pass pCi Mn-54 143 137 95.9 178 Pass pCi Zn-65 71.0 66.4 46.5 86.3 Pass 6/13/2024 E14042A Filter pCi Beta Cs-137 249 220 154 286 Pass 9/12/2024 E14043 Filter pCi Beta Cs-137 242 221 84.7 157 Pass 9/12/2024 E14102 Soil pCi/g Cs-134 0.318 0.336 0.235 0.437 Pass pCi/g Cs-137 0.287 0.295 0.207 0.384 Pass 9/12/2024 E14102 Soil pCi/g Cs-134 0.299 0.336 0.235 0.437 Pass pCi/g Cs-137 0.269 0.295 0.207 0.384 Pass 9/12/2024 E14102 Soil pCi/g Cs-134 0.305 0.336 0.235 0.437 Pass pCi/g Cs-137 0.277 0.295 0.207 0.384 Pass 9/12/2024 E14102 Soil pCi/g Cs-134 0.312 0.336 0.235 0.437 Pass pCi/g Cs-137 0.282 0.295 0.207 0.384 Pass 9/16/2024 MRAD-41 Filter pCi Cs-134 499 581 377 712 Pass pCi Cs-137 880 848 696 1110 Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 67 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 9/16/2024 MRAD-41 Filter pCi Co-60 865 839 713 1070 Pass pCi Zn-65 269 239 196 365 Pass 10/4/2024 RAD-139 Water pCi/L Cs-134 79.6 80.2 63.0 97.4 Pass pCi/L Cs-137 49.7 46.3 23.3 69.3 Pass pCi/L Co-60 47.9 45.3 31.6 59.0 Pass pCi/L Zn-65 108 114 75.0 153 Pass 10/4/2024 RAD-139 Water pCi/L Cs-134 79.8 80.2 63.0 97.4 Pass pCi/L Cs-137 46.0 46.3 23.3 69.3 Pass pCi/L Co-60 49.4 45.3 31.6 59.0 Pass 10/4/2024 RAD-139 Water pCi/L Zn-65 106 114 75.0 153 Pass 10/4/2024 RAD-139 Water pCi/L Cs-134 79.4 80.2 63.0 97.4 Pass pCi/L Cs-137 46.3 46.3 23.3 69.3 Pass pCi/L Co-60 47.5 45.3 31.6 59.0 Pass pCi/L Zn-65 106 114 75.0 153 Pass 10/4/2024 RAD-139 Water pCi/L I-131 26.4 26.3 22.7 29.9 Pass 10/4/2024 RAD-139 Water pCi/L I-131 26.3 26.3 22.7 29.9 Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 68 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 12/5/2024 E14044 Filter pCi Ce-141 75.7 74.8 52 97 Pass pCi Co-58 105 97.9 69 127 Pass pCi Cr-60 220 219 153 285 Pass pCi Cr-51 182 185 130 241 Pass pCi Cs-134 97.9 116 81 151 Pass pCi Cs-137 144 144 101 187 Pass pCi Fe-59 130 107 75 139 Pass pCi Mn-54 113 104 73 135 Pass pCi Zn-65 164 155 109 202 Pass 12/5/2024 E14044 Filter pCi Ce-141 69.3 74.8 52 97 Pass pCi Co-58 93.7 97.9 69 127 Pass pCi Cr-60 196 219 153 285 Pass pCi Cr-51 166 185 130 241 Pass pCi Cs-134 91.3 116 81 151 Fail 1 pCi Cs-137 135 144 101 187 Pass pCi Fe-59 113 107 75 139 Pass pCi Mn-54 106 104 73 135 Pass pCi Zn-65 146 155 109 202 Pass 12/5/2024 E14044 Filter pCi Ce-141 66.6 74.8 52 97 Pass pCi Co-58 92.4 97.9 69 127 Pass pCi Cr-60 204 219 153 285 Pass pCi Cr-51 175 185 130 241 Pass pCi Cs-134 95.7 116 81 151 Pass pCi Cs-137 139 144 101 187 Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 69 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 12/5/2024 E14044 Filter pCi Fe-59 119 107 75 139 Pass pCi Mn-54 102 104 73 135 Pass pCi Zn-65 139 155 109 202 Pass 12/5/2024 E14045 Water pCi/L Beta Cs-137 257 240 168 312 Pass 12/5/2024 E14046 Charcoal pCi I-131 58.0 65.3 45.7 84.9 Pass pCi I-131 59.3 65.3 45.7 84.9 Pass pCi I-131 59.4 65.3 45.7 84.9 Pass 12/5/2024 E14047 Milk pCi/L Ce-141 74.7 71.6 50.1 93.1 Pass pCi/L Co-58 95.2 93.7 65.6 122 Pass pCi/L Co-60 211 210 147 273 Pass pCi/L Cr-51 164 177 124 230 Pass pCi/L Cs-134 114 111 77.7 144 Pass pCi/L Cs-137 150 138 96.6 179 Pass pCi/L Fe-59 112 102 71.4 133 Pass pCi/L I-131 50.1 51.0 35.7 66.3 Pass pCi/L Mn-54 106 99.5 69.7 129 Pass pCi/L Zn-65 141 149 104 194 Pass 12/5/2024 E14047 Milk pCi/L Ce-141 77.8 71.6 50.1 93.1 Pass pCi/L Co-58 96.9 93.7 65.6 122 Pass pCi/L Co-60 208 210 147 273 Pass pCi/L Cr-51 205 177 124 230 Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 70 of 82 Company: Constellation Plant: Limerick Generating Station Table 14, Cross Check Intercomparison Results Study Date Study ID Units Radionuclide Reported Value Assigned Value Acceptance Performance Evaluation Lower Limit Upper Limit 12/5/2024 E14047 Milk pCi/L Cs-134 110 111 77.7 144 Pass pCi/L Cs-137 140 138 96.6 179 Pass pCi/L Fe-59 100 102 71.4 133 Pass pCi/L I-131 45.5 51.0 35.7 66.3 Pass pCi/L Mn-54 109 99.5 69.7 129 Pass pCi/L Zn-65 136 149 104 194 Pass 12/5/2024 E14047 Milk pCi/L Ce-141 71.9 71.6 50.1 93.1 Pass pCi/L Co-58 89.7 93.7 65.6 122 Pass pCi/L Co-60 232 210 147 273 Pass pCi/L Cr-51 180 177 124 230 Pass pCi/L Cs-134 113 111 77.7 144 Pass pCi/L Cs-137 149 138 96.6 179 Pass pCi/L Fe-59 112 102 71.4 133 Pass pCi/L I-131 63.3 51.0 35.7 66.3 Pass pCi/L Mn-54 105 99.5 69.7 129 Pass pCi/L Zn-65 148 149 104 194 Pass 1 See Discussion at the beginning of Attachment 3

Annual Radiological Environmental Operating Report YEAR: 2024 Page 71 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Sample Type Location Sample Date Analysis Result Units CGS Analysis w 2 Split Analysis w 2

Pass/Fail (Split)

Water 16C2 1/29/2024 Gross Beta pCi/L 1.97 0.828 2.97+/-1.57 Pass Water 16C2 1/29/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 1/29/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 3/04/2024 Gross Beta pCi/L 1.76 0.784 2.98+/-1.44 Pass Water 16C2 3/04/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 3/04/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 4/01/2024 Gross Beta pCi/L 1.57 0.770

<MDA Pass Water 16C2 4/01/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 4/01/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 4/01/2024 Tritium pCi/L

<MDA

<MDA Pass Water 16C2 4/29/2024 Gross Beta pCi/L 1.65 0.736 3.31+/-1.68 Pass Water 16C2 4/29/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 4/29/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 6/3/2024 Gross Beta pCi/L 2.06 0.772 4.2+/-1.67 Pass Water 16C2 6/3/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 6/3/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 7/1/2024 Gross Beta pCi/L 2.84 0.801 3.17+/-1.68 Pass Water 16C2 7/1/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 7/1/2024 Gamma pCi/L

<MDA

<MDA Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 72 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Sample Type Location Sample Date Analysis Result Units CGS Analysis w 2 Split Analysis w 2

Pass/Fail (Split)

Water 16C2 7/1/2024 Tritium pCi/L

<MDA

<MDA Pass Water 16C2 7/29/2024 Gross Beta pCi/L 2.50 0.810 3.75+/-1.80 Pass Water 16C2 7/29/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 7/29/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 9/3/2024 Gross Beta pCi/L 2.70 0.827 3.82+/-1.68 Pass Water 16C2 9/3/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 9/3/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 9/30/2024 Gross Beta pCi/L 3.96 0.851 3.92+/-1.75 Pass Water 16C2 9/30/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 9/30/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 9/30/2024 Tritium pCi/L

<MDA

<MDA Pass Water 16C2 10/28/2024 Gross Beta pCi/L 3.74 0.922 4.44+/-2.33 Pass Water 16C2 10/28/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 10/28/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 12/2/2024 Gross Beta pCi/L 2.75 0.876 3.14+/-1.93 Pass Water 16C2 12/2/2024 LLI pCi/L

<MDA

<MDA Pass Water 16C2 12/2/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 12/30/2024 Gross Beta pCi/L 3.78 1.13 3.08+/-1.63 Pass Water 16C2 12/30/2024 LLI pCi/L

<MDA

<MDA Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 73 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Sample Type Location Sample Date Analysis Result Units CGS Analysis w 2 Split Analysis w 2

Pass/Fail (Split)

Water 16C2 12/30/2024 Gamma pCi/L

<MDA

<MDA Pass Water 16C2 12/30/2024 Tritium pCi/L

<MDA

<MDA Pass Milk 19B1 1/17/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 19B1 1/17/2024 LLI pCi/L

<MDA

<MDA Pass Milk 22B1 1/17/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 22B1 1/17/2024 LLI pCi/L

<MDA

<MDA Pass Milk 19B1 4/2/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 19B1 4/2/2024 LLI pCi/L

<MDA

<MDA Pass Milk 22B1 4/2/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 22B1 4/2/2024 LLI pCi/L

<MDA

<MDA Pass Milk 19B1 7/9/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 19B1 7/9/2024 LLI pCi/L

<MDA

<MDA Pass Milk 22B1 7/9/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 22B1 7/9/2024 LLI pCi/L

<MDA

<MDA Pass Milk 19B1 10/01/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 19B1 10/01/2024 LLI pCi/L

<MDA

<MDA Pass Milk 22B1 10/01/2024 Gamma pCi/L

<MDA

<MDA Pass Milk 22B1 10/01/2024 LLI pCi/L

<MDA

<MDA Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 74 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Sample Type Location Sample Date Analysis Result Units CGS Analysis w 2 Split Analysis w 2

Pass/Fail (Split)

Filter Composite 11S2 4/01/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite 11S2 7/01/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite 11S2 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite 11S2 12/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Sediment J2-1 10/29/24 Gamma pCi/Kg

<MDA

<MDA Pass Water WA1 6/28/2024 Gamma pCi/L

<MDA

<MDA Pass Water WA2 6/28/2024 Gamma pCi/L

<MDA

<MDA Pass Oysters IA3 6/19/2024 Gamma pCi/Kg

<MDA

<MDA Pass Oysters IA6 6/19/2024 Gamma pCi/Kg

<MDA

<MDA Pass Bottom Sediment WBS4 6/19/2024 Gamma pCi/Kg

<MDA

<MDA Pass Bottom Sediment WBS2 6/19/2024 Gamma pCi/Kg

<MDA

<MDA Pass Vegetation IB10 7/22/2024 Gamma pCi/Kg

<MDA

<MDA Pass Vegetation IB11 7/22/2024 Gamma pCi/Kg

<MDA

<MDA Pass Vegetation IB12 7/22/2024 Gamma pCi/Kg

<MDA

<MDA Pass Vegetation East 7/23/2024 Gamma pCi/Kg

<MDA

<MDA Pass Milk Farm A 09/03/2024 Gamma Gamma pCi/L

<MDA Pass Milk Farm A 09/03/2024 Gamma LLI pCi/L

<MDA Pass Milk Farm B 09/03/2024 Gamma Gamma pCi/L

<MDA Pass

Annual Radiological Environmental Operating Report YEAR: 2024 Page 75 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Sample Type Location Sample Date Analysis Result Units CGS Analysis w 2 Split Analysis w 2

Pass/Fail (Split)

Milk Farm B 09/03/2024 Gamma LLI pCi/L

<MDA Pass Milk

55 09/09/2024 Gamma Gamma pCi/L

<MDA Pass Milk

55 09/09/2024 Gamma LLI pCi/L

<MDA Pass Fish (Spanish Mackerel)

IA1 8/14/2024 Gamma pCi/kg

<MDA

<MDA Pass Filter Composite CC-A1 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-A2 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-A3 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-A4 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-A5 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-SFA1 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-SFA2 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-SFA3 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass Filter Composite CC-SFA4 9/30/2024 Gamma pCi/m3

<MDA

<MDA Pass LLI=Low Level Iodine

Annual Radiological Environmental Operating Report YEAR: 2024 Page 76 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Air Particulate Beta and Air Iodine Co-Located Sample Type Location Sample Date Analysis Result Units 11S1 CGS Result +/- 2 11S2 (Q)

TBE Split Result +/- 2 Filter 11S1 / 11S2 (Q) 1/8/2024 Beta pCi/M3 1.50E-02 2.13E-03 9.90E-03 3.75E-03 Filter 11S1 / 11S2 (Q) 1/16/2024 Beta pCi/M3 2.74E-02 2.13E-03 1.39E-02 3.47E-03 Filter 11S1 / 11S2 (Q) 1/22/2024 Beta pCi/M3 2.86E-02 2.57E-03 1.80E-02 4.61E-03 Filter 11S1 / 11S2 (Q) 1/29/2024 Beta pCi/M3 1.72E-02 1.96E-03 1.05E-02 3.42E-03 Filter 11S1 / 11S2 (Q) 2/6/2024 Beta pCi/M3 1.44E-02 1.75E-03 1.58E-02 3.56E-03 Filter 11S1 / 11S2 (Q) 2/12/2024 Beta pCi/M3 1.94E-02 2.30E-03 1.43E-02 4.13E-03 Filter 11S1 / 11S2 (Q) 2/19/2024 Beta pCi/M3 2.27E-02 2.15E-03 1.65E-02 3.75E-03 Filter 11S1 / 11S2 (Q) 2/26/2024 Beta pCi/M3 2.20E-02 2.14E-03 1.86E-02 3.95E-03 Filter 11S1 / 11S2 (Q) 3/4/2024 Beta pCi/M3 2.09E-02 2.08E-03 1.65E-02 3.69E-03 Filter 11S1 / 11S2 (Q) 3/11/2024 Beta pCi/M3 5.73E-03 1.50E-03 4.73E-03 3.00E-03 Filter 11S1 / 11S2 (Q) 3/18/2024 Beta pCi/M3 2.93E-02 2.37E-03 2.16E-02 4.13E-03 Filter 11S1 / 11S2 (Q) 3/25/2024 Beta pCi/M3 1.14E-02 1.80E-03 9.19E-03 3.44E-03 Filter 11S1 / 11S2 (Q) 4/1/2024 Beta pCi/M3 1.81E-02 1.94E-03 1.64E-02 3.88E-03 Filter 11S1 / 11S2 (Q) 4/8/2024 Beta pCi/M3 1.07E-02 1.62E-03 7.40E-03 3.12E-03 Filter 11S1 / 11S2 (Q) 4/15/2024 Beta pCi/M3 1.84E-02 1.98E-03 1.52E-02 3.76E-03 Filter 11S1 / 11S2 (Q) 4/22/2024 Beta pCi/M3 1.60E-02 1.94E-03 1.75E-02 3.94E-03 Filter 11S1 / 11S2 (Q) 4/29/2024 Beta pCi/M3 1.93E-02 2.10E-03 1.44E-02 4.15E-03 Filter 11S1 / 11S2 (Q) 5/6/2024 Beta pCi/M3 1.64E-02 1.98E-03 1.01E-02 3.56E-03 Filter 11S1 / 11S2 (Q) 5/13/2024 Beta pCi/M3 1.17E-02 1.77E-03 9.62E-03 3.11E-03 Filter 11S1 / 11S2 (Q) 5/20/2024 Beta pCi/M3 1.53E-02 1.94E-03 1.23E-02 3.60E-03 Filter 11S1 / 11S2 (Q) 5/28/2024 Beta pCi/M3 2.13E-02 1.89E-03 1.72E-02 3.39E-03 Filter 11S1 / 11S2 (Q) 6/3/2024 Beta pCi/M3 2.01E-02 2.28E-03 1.14E-02 4.30E-03 Filter 11S1 / 11S2 (Q) 6/10/2024 Beta pCi/M3 2.13E-02 2.10E-03 1.55E-02 4.01E-03 Filter 11S1 / 11S2 (Q) 6/17/2024 Beta pCi/M3 1.66E-02 1.95E-03 1.32E-02 3.83E-03 Filter 11S1 / 11S2 (Q) 6/25/2024 Beta pCi/M3 2.67E-02 2.08E-03 1.64E-02 3.52E-03

Annual Radiological Environmental Operating Report YEAR: 2024 Page 77 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Air Particulate Beta and Air Iodine Co-Located Sample Type Location Sample Date Analysis Result Units 11S1 CGS Result +/- 2 11S2 (Q)

TBE Split Result +/- 2 Filter 11S1 / 11S2 (Q) 7/1/2024 Beta pCi/M3 1.59E-02 2.09E-03 1.57E-02 4.17E-03 Filter 11S1 / 11S2 (Q) 7/8/2024 Beta pCi/M3 1.88E-02 2.01E-03 1.74E-02 3.78E-03 Filter 11S1 / 11S2 (Q) 7/15/2024 Beta pCi/M3 1.95E-02 2.09E-03 1.66E-02 3.81E-03 Filter 11S1 / 11S2 (Q) 7/22/2024 Beta pCi/M3 2.50E-02 2.27E-03 1.74E-02 4.10E-03 Filter 11S1 / 11S2 (Q) 7/29/2024 Beta pCi/M3 1.98E-02 2.06E-03 1.47E-02 3.68E-03 Filter 11S1 / 11S2 (Q) 8/5/2024 Beta pCi/M3 2.56E-02 2.28E-03 2.40E-02 4.52E-03 Filter 11S1 / 11S2 (Q) 8/12/2024 Beta pCi/M3 1.69E-02 1.99E-03 1.43E-02 3.88E-03 Filter 11S1 / 11S2 (Q) 8/19/2024 Beta pCi/M3 2.30E-02 2.19E-03 1.38E-02 4.02E-03 Filter 11S1 / 11S2 (Q) 8/26/2024 Beta pCi/M3 2.00E-02 2.11E-03 1.78E-02 3.96E-03 Filter 11S1 / 11S2 (Q) 9/3/2024 Beta pCi/M3 3.63E-02 2.39E-03 2.15E-02 4.07E-03 Filter 11S1 / 11S2 (Q) 9/9/2024 Beta pCi/M3 1.38E-02 2.10E-03 9.44E-03 4.37E-03 Filter 11S1 / 11S2 (Q) 9/16/2024 Beta pCi/M3 3.20E-02 2.49E-03 2.50E-02 4.62E-03 Filter 11S1 / 11S2 (Q) 9/23/2024 Beta pCi/M3 2.73E-02 2.29E-03 2.14E-02 4.23E-03 Filter 11S1 / 11S2 (Q) 9/30/2024 Beta pCi/M3 9.12E-03 1.63E-03 6.31E-03 3.25E-03 Filter 11S1 / 11S2 (Q) 10/7/2024 Beta pCi/M3 2.04E-02 2.08E-03 1.55E-02 3.84E-03 Filter 11S1 / 11S2 (Q) 10/14/2024 Beta pCi/M3 4.27E-02 2.73E-03 1.87E-02 4.17E-03 Filter 11S1 / 11S2 (Q) 10/21/2024 Beta pCi/M3 1.84E-02 1.99E-03 1.13E-02 3.87E-03 Filter 11S1 / 11S2 (Q) 10/29/2024 Beta pCi/M3 2.97E-02 2.25E-03 2.46E-02 4.23E-03 Filter 11S1 / 11S2 (Q) 11/4/2024 Beta pCi/M3 4.41E-02 3.05E-03 1.85E-02 4.62E-03 Filter 11S1 / 11S2 (Q) 11/11/2024 Beta pCi/M3 2.04E-02 2.10E-03 1.18E-02 3.99E-03 Filter 11S1 / 11S2 (Q) 11/18/2024 Beta pCi/M3 1.63E-02 1.99E-03 1.28E-02 3.98E-03 Filter 11S1 / 11S2 (Q) 11/25/2024 Beta pCi/M3 2.31E-02 2.11E-03 1.82E-02 4.17E-03 Filter 11S1 / 11S2 (Q) 12/2/2024 Beta pCi/M3 2.62E-02 2.29E-03 1.99E-02 4.20E-03 Filter 11S1 / 11S2 (Q) 12/9/2024 Beta pCi/M3 2.19E-02 2.19E-03 1.34E-02 4.03E-03 Filter 11S1 / 11S2 (Q) 12/16/2024 Beta pCi/M3 2.65E-02 2.25E-03 1.78E-02 4.06E-03 Filter 11S1 / 11S2 (Q) 12/23/2024 Beta pCi/M3 1.31E-02 1.82E-03 7.32E-03 3.44E-03

Annual Radiological Environmental Operating Report YEAR: 2024 Page 78 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Air Particulate Beta and Air Iodine Co-Located Sample Type Location Sample Date Analysis Result Units 11S1 CGS Result +/- 2 11S2 (Q)

TBE Split Result +/- 2 Filter 11S1 / 11S2 (Q) 12/30/2024 Beta pCi/M3 1.88E-02 2.01E-03 1.38E-02 3.69E-03 Charcoal 11S1 / 11S2 (Q) 1/8/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 1/16/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 1/22/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 1/29/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 2/6/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 2/12/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 2/19/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 2/26/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 3/4/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 3/11/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 3/18/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 3/25/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 4/1/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 4/8/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 4/15/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 4/22/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 4/29/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 5/6/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 5/13/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 5/20/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 5/28/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 6/3/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 6/10/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 6/17/2024 I-131 pCi/M3

<MDA

Annual Radiological Environmental Operating Report YEAR: 2024 Page 79 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Air Particulate Beta and Air Iodine Co-Located Sample Type Location Sample Date Analysis Result Units 11S1 CGS Result +/- 2 11S2 (Q)

TBE Split Result +/- 2 Charcoal 11S1 / 11S2 (Q) 6/25/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 7/1/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 7/8/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 7/15/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 7/22/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 7/29/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 8/5/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 8/12/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 8/19/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 8/26/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 9/3/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 9/9/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 9/16/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 9/23/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 9/30/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 10/7/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 10/14/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 10/21/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 10/29/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 11/4/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 11/11/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 11/18/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 11/25/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 12/2/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 12/9/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 12/16/2024 I-131 pCi/M3

<MDA

Annual Radiological Environmental Operating Report YEAR: 2024 Page 80 of 82 Company: Constellation Plant: Limerick Generating Station Table 15, Split Sample Intercomparison Results Air Particulate Beta and Air Iodine Co-Located Sample Type Location Sample Date Analysis Result Units 11S1 CGS Result +/- 2 11S2 (Q)

TBE Split Result +/- 2 Charcoal 11S1 / 11S2 (Q) 12/23/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 12/30/2024 I-131 pCi/M3

<MDA

<MDA Charcoal 11S1 / 11S2 (Q) 1/2/2025 I-131 pCi/M3

<MDA

<MDA (Q) - Indicates a Quality Control duplicate sample location

Annual Radiological Environmental Operating Report YEAR: 2024 Page 81 of 82 Company: Constellation Plant: Limerick Generating Station

, Environmental Direct Radiation Dosimetry Results Monitoring Location Quarterly

Baseline, BQ (mrem)

BQ +

MDDQ (mrem)

Normalized Quarterly Monitoring Data, MQ Quarterly Facility Dose, FQ=MQ-BQ Annual

Baseline, BA (mrem)

BA +

MDDA (mrem)

Annual Monitoring Data, MA (mrem)

Annual Facility Dose, FA=MA-BA (mrem, or ND if FA MDDA)

(mrem)

(mrem, or ND if FQ MDDQ) 1 2

3 4

1 2

3 4

10E1 17.7 22.5 16.4 18.8 16.8 18.7 ND ND ND ND 71.0 82.7 70.7 ND 10F3 17.4 22.2 19.4 18.9 17.2 17.3 ND ND ND ND 69.7 81.4 72.8 ND 10S3 17.7 22.4 17.8 19.1 19.2 18.9 ND ND ND ND 70.9 82.6 75.0 ND 11S1 20.8 25.5 22.1 22.6 21.0 22.3 ND ND ND ND 83.1 94.8 88.1 ND 13C1 12.5 17.2 14.8 12.4 11.8 13.0 ND ND ND ND 49.8 61.5 52.0 ND 13E1 17.5 22.2 18.7 20.0 18.2 19.5 ND ND ND ND 70.1 81.8 76.5 ND 13S2 28.0 32.8 24.6 25.7 23.7 26.4 ND ND ND ND 112.1 123.8 100.4 ND 14S1 15.8 20.5 16.6 18.0 15.8 16.2 ND ND ND ND 63.2 74.9 66.6 ND 15D1 18.1 22.9 16.2 21.9 16.6 18.4 ND ND ND ND 72.5 84.2 73.2 ND 16F1 18.4 23.1 18.7 19.2 17.8 18.6 ND ND ND ND 73.4 85.1 74.3 ND 17B1 16.7 21.4 17.1 17.6 15.4 16.4 ND ND ND ND 66.8 78.5 66.6 ND 18S2 19.6 24.3 19.7 20.0 18.7 19.1 ND ND ND ND 78.4 90.1 77.5 ND 19D1 16.6 21.3 17.2 16.8 16.4 18.3 ND ND ND ND 66.3 78.0 68.6 ND 20D1 15.7 20.5 17.6 16.2 15.6 15.9 ND ND ND ND 63.0 74.7 65.3 ND 20F1 16.9 21.6 17.0 17.4 16.4 18.0 ND ND ND ND 67.5 79.2 68.8 ND 21S2 16.0 20.7 16.2 16.9 14.9 16.1 ND ND ND ND 64.1 75.8 64.1 ND 23S2 16.0 20.7 15.4 16.8 15.4 16.8 ND ND ND ND 63.9 75.6 64.5 ND 24D1 14.9 19.6 14.4 14.6 15.0 14.2 ND ND ND ND 59.7 71.4 58.1 ND 25D1 14.1 18.8 14.1 15.9 13.6 14.8 ND ND ND ND 56.5 68.2 58.3 ND 25S2 14.5 19.3 17.8 15.1 15.3 16.0 ND ND ND ND 58.1 69.8 64.2 ND 26S3 15.1 19.8 14.2 16.2 13.8 15.4 ND ND ND ND 60.4 72.1 59.6 ND 28D2 15.9 20.6 18.5 16.0 15.3 15.5 ND ND ND ND 63.5 75.2 65.3 ND 29E1 15.6 20.3 16.5 17.7 15.3 16.9 ND ND ND ND 62.3 74.0 66.5 ND 29S1 15.3 20.1 15.8 16.3 13.8 16.2 ND ND ND ND 61.4 73.1 62.0 ND

Annual Radiological Environmental Operating Report YEAR: 2024 Page 82 of 82 Company: Constellation Plant: Limerick Generating Station

, Environmental Direct Radiation Dosimetry Results Monitoring Location Quarterly

Baseline, BQ (mrem)

BQ +

MDDQ (mrem)

Normalized Quarterly Monitoring Data, MQ Quarterly Facility Dose, FQ=MQ-BQ Annual

Baseline, BA (mrem)

BA +

MDDA (mrem)

Annual Monitoring Data, MA (mrem)

Annual Facility Dose, FA=MA-BA (mrem, or ND if FA MDDA)

(mrem)

(mrem, or ND if FQ MDDQ) 1 2

3 4

1 2

3 4

2E1 18.0 22.7 17.7 18.4 20.5 18.8 ND ND ND ND 71.9 83.6 75.3 ND 31D1 20.7 25.5 21.7 20.2 17.8 19.2 ND ND ND ND 83.0 94.7 79.0 ND 31D2 17.8 22.5 19.7 18.4 17.3 17.0 ND ND ND ND 71.2 82.9 72.3 ND 31S1 17.9 22.6 17.8 19.4 17.9 18.5 ND ND ND ND 71.6 83.3 73.5 ND 34E1 16.8 21.5 18.3 18.9 16.2 17.9 ND ND ND ND 67.0 78.7 71.2 ND 34S2 17.9 22.6 18.5 18.4 16.1 17.3 ND ND ND ND 71.6 83.3 70.2 ND 36D1 15.5 20.3 15.5 15.9 13.8 15.1 ND ND ND ND 62.1 73.8 60.4 ND 36S2 18.3 23.1 17.1 18.7 18.6 17.7 ND ND ND ND 73.4 85.1 72.1 ND 3S1 17.5 22.3 17.4 18.1 18.0 17.4 ND ND ND ND 70.1 81.8 70.8 ND 4E1 12.9 17.6 14.2 12.5 11.1 12.8 ND ND ND ND 51.4 63.1 50.7 ND 5H1 21.6 26.3 22.1 25.2 18.1 20.2 ND ND ND ND 86.3 98.0 85.6 ND 5S1 20.0 24.7 19.4 21.1 17.9 20.2 ND ND ND ND 80.0 91.7 78.6 ND 6C1 17.4 22.1 16.2 19.6 19.0 18.7 ND ND ND ND 69.5 81.2 73.4 ND 7E1 18.6 23.4 17.3 19.5 18.9 19.2 ND ND ND ND 74.6 86.3 74.9 ND 7S1 18.3 23.0 19.9 17.9 17.6 18.4 ND ND ND ND 73.1 84.8 73.8 ND 9C1 17.0 21.7 18.1 17.5 17.2 18.5 ND ND ND ND 68.1 79.8 71.4 ND MDDQ = Quarterly Minimum Differential Dose = 4.73 mrem MDDA = Annual Minimum Differential Dose = 11.7 mrem ND = Not Detected, where MQ (BQ+MDDQ) or MA (BA+MDDA)

LG-25-068, 2024 Annual Radiological Environmental Operating Report

Contents

Text

Subject:

Attachment:

SUMMARY

3.0 INTRODUCTION

SUMMARY

Conclusions:

3.0 INTRODUCTION

Navigation menu

LG-25-068, 2024 Annual Radiological Environmental Operating Report

Text

Subject:

Attachment:

SUMMARY

3.0 INTRODUCTION

SUMMARY

Conclusions:

3.0 INTRODUCTION

Navigation menu

Search