Text

Annual Radiological Environmental Operating Report for 2024
	ML25134A078
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/14/2025
From:	Keele R; Entergy Operations
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	0CAN052501
	Download: ML25134A078 (1)
	v • d • e

0CAN052501 10 CFR 50, Appendix I May 14, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Annual Radiological Environmental Operating Report for 2024 Arkansas Nuclear One - Units 1 and 2 NRC Docket Nos. 50-313 and 50-368 Renewed Facility Operating License Nos. DPR-51 and NPF-6

Reference:

Entergy Operations, Inc. (Entergy) letter to the U. S. Nuclear Regulatory Commission (NRC), "Radioactive Effluent Release Report for the 2024 Calendar Year," (ADAMS Accession Number ML25111A232),

(0CAN042502), dated April 21, 2025.

In accordance with Entergy Operations', Inc. (Entergys), Arkansas Nuclear One (ANO), Unit 1 Technical Specification (TS) 5.6.2 and Unit 2 TS 6.6.2, the submittal of an annual radiological environmental operating report for the previous year is required by May 15, of each year. Both ANO-1 TS 5.6.2 and ANO-2 TS 6.6.2 note that a single submittal may be made for ANO. The submittal should combine sections common to both units.

The radionuclides detected by the radiological environmental monitoring program during 2024, were significantly below the regulatory limits. The operation of the ANO station, during 2024, had no harmful radiological effects nor resulted in any irreversible damage to the local environment.

No environmental samples from the monitoring program equaled or exceeded the reporting levels for radioactivity concentration due to ANO effluents when averaged over any calendar quarter. A map of sampling locations and a corresponding table providing the respective distances and directions from the reactor containment buildings is included in the Offsite Dose Calculation Manual (ODCM). The ODCM was submitted as part of the referenced document.

The subject ANO report for the calendar year 2024 is enclosed. This report fulfills the reporting requirements of the TSs.

Entergy Operations, Inc. 1448 S.R 333 Russellville, AR 72802 Riley D. Keele, Jr.

Manager, Regulatory Assurance Arkansas Nuclear One Tel 479-858-7826

0CAN05250 I Page 2 of 2 This letter contains no new regulatory commitments.

Should you have any questions or require additional information, please contact Riley Keele, Manager, Regulatory Assurance, at (479) 858-7826.

Respectfully, Riley Keele RDKIrwc

Enclosure:

Annual Radiological Environmental Operating Report for 2024 cc:

NRC Region IV Regional Administrator NRC Senior Resident Inspector Arkansas Nuclear One NRC Project Manager Arkansas Nuclear One Designated Arkansas State Official

ENCLOSURE 0CAN052501 ANNUAL RADIOLOGICAL ENVIROMENTAL OPERATING REPORT FOR 2024

Arkansas Nuclear One 2024 Document Number: 0CAN052501 Annual Radiological Environmental Operating Report

Annual Radiological Environmental Operating Report YEAR: 2024 Page 1 of 61 Company: Entergy Plant: Arkansas Nuclear One 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

........................................................................................................................... 6 4.0 SITE DESCRIPTION AND SAMPLE LOCATIONS....................................................................... 7 5.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM REQUIREMENTS................. 8 6.0 MAPS OF COLLECTION SITES................................................................................................. 14 7.0 REPORTING LEVELS FOR RADIOACTIVITY CONCENTRATIONS IN ENVIRONMENTAL SAMPLES................................................................................................... 17 8.0 SAMPLING PROGRAM, PROGRAM MODIFICATION AND INTEPRETATION OF RESULTS.................................................................................................................................... 18 8.1 Environmental Direct Radiation Dosimetry Results......................................................... 18 8.2 Air Particulate and Radioiodine Sample Results............................................................. 18 8.3 Waterborne Sample Results........................................................................................... 19 8.4 Ingestion Pathway Sample Results................................................................................. 22 9.0 LAND USE CENSUS.................................................................................................................. 23 10.0 SAMPLE DEVIATIONS, ANOMALIES AND UNAVAILABILITY................................................. 24 11.0 OTHER SUPPLEMENTAL INFORMATION................................................................................ 25 11.1 NEI 07-07 Onsite Radiological Groundwater Monitoring Program.................................. 25 11.2 Program Modifications..................................................................................................... 26 11.3 Corrections to Previous Reports..................................................................................... 26 12.0 BIBLIOGRAPHY......................................................................................................................... 27 TABLES Table 1, Radiological Environmental Monitoring Program - Direct Radiation.......................................... 8 Table 2, Radiological Environmental Monitoring Program - Airborne...................................................... 9 Table 3, Radiological Environmental Monitoring Program - Waterborne............................................... 10 Table 4, Radiological Environmental Monitoring Program - Ingestion................................................... 11 Table 5, REMP Sampling Locations - Direct Radiation.......................................................................... 12 Table 6, Reporting Levels for Radioactivity Concentrations in Environmental Samples........................ 17 Table 7, Maximum Values for the Limit of Detection.............................................................................. 17 Table 8: Land Use Census - Nearest Receptors within 5 miles............................................................. 24 Table 9: Sample Deviation Summary..................................................................................................... 25 Table 10: Air Particulate Data Summary Tables (Gross Beta - pCi/m3)................................................ 33 Table 11: Air Particulate Data Summary Tables (I-131 - pCi/m3).......................................................... 34 Table 12, Surface Water - Gamma........................................................................................................ 35 Table 13, Surface Water - Tritium.......................................................................................................... 38 Table 14, Drinking Water -Gamma, GB, I-131....................................................................................... 39 Table 15, Drinking Water - Tritium......................................................................................................... 40 Table 16, Fish......................................................................................................................................... 40

Annual Radiological Environmental Operating Report YEAR: 2024 Page 2 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 17, Sediment................................................................................................................................. 41 Table 18, Food Products........................................................................................................................ 41 Table 19, Groundwater - Gamma and Iodine......................................................................................... 42 Table 20, Groundwater - Tritium............................................................................................................ 44 Table 21, Thermoluminescent Dosimeters - Inner Ring......................................................................... 45 Table 22, Thermoluminescent Dosimeters - Special Interest Areas...................................................... 46 Table 23, Thermoluminescent Dosimeters - Control Location............................................................... 46 FIGURES Figure 1, Potential exposure pathways to Members of the Public due to Plant Operations [7]................ 6 Figure 2, REMP Sample Locations (Near Field/Site Boundary)............................................................. 14 Figure 3, REMP Sample Locations (Far Field)....................................................................................... 15 Figure 4, REMP Sample Locations (Onsite)........................................................................................... 16 Figure 5, Air Particulate: Analysis for Gross Beta, Average for All Indicator and Control Locations...... 19 Figure 6: Surface Water Tritium Results................................................................................................. 19 Figure 7: REMP Groundwater Tritium Sample Results.......................................................................... 20 Figure 8: Drinking Water Gross Beta Samples Control vs. Indicator Comparison.................................. 21 ATTACHMENTS, Data Table Summary....................................................................................................... 29, Complete Data Table for All Analysis Results Obtained In 2024..................................... 33, Cross Check Intercomparison Program........................................................................... 47

Annual Radiological Environmental Operating Report YEAR: 2024 Page 3 of 61 Company: Entergy Plant: Arkansas Nuclear One 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 3.7E10 disintegrations per second, or 2.22E12 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.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 4 of 61 Company: Entergy Plant: Arkansas Nuclear One

16.

MDA: Minimum Detectable Activity. For radiochemistry instruments, the MDA is the a posteriori minimum concentration that a counting system detects. 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. Essentially synonymous with MDA for the purposes of radiological monitoring.

18.

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

19.

Microcurie: 3.7E04 disintegrations per second, or 2.22E08 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

Arkansas Nuclear One (ANO) 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 ANO 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). The program compares data from Indicator locations near the plant, to Control locations farther away from the site to assess operation impacts.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 5 of 61 Company: Entergy Plant: Arkansas Nuclear One The Annual Radiological Environmental Operating Report (AREOR) provides data obtained through analyses of environmental samples collected at ANO for the reporting period of January 1st through December 31st, 2024. During that time period 273 analyses were performed on 273 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 ANO, 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 ANO. Naturally occurring radionuclides are present in the Earth's crust and atmosphere and exists 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. Detailed information on the exposure of the U.S. population to ionizing radiation can be found in National Council on Radiation Protection and Measurementn (NCRP) Report No. 160 [1].

Annual Radiological Environmental Operating Report YEAR: 2024 Page 6 of 61 Company: Entergy Plant: Arkansas Nuclear One

3.0 INTRODUCTION

The ANO 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

[2], and implements the requirements of Section IV.B.2 and IV.B.3 of Appendix I.

REMP is designed to conform to the NRC Regulatory Guide 4.1 [3],

NUREG 1301/1302 [4] [5], and the 1979 NRC Branch Technical Position [6].

Figure 1, Potential exposure pathways to Members of the Public due to Plant Operations [7]

Quality assurance aspects of the sampling program and TLD/OSLD data collection are conducted in accordance with Regulatory Guides 4.15 [8] and 4.13 [9]. REMP also adheres to the requirements of ANO Technical Specifications, and ODCM.

These governing documents dictate the environmental sampling, sample analysis protocols, data reporting and quality assurance requirements for the environmental monitoring program.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 7 of 61 Company: Entergy Plant: Arkansas Nuclear One The AREOR 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.

4.0 SITE DESCRIPTION AND SAMPLE LOCATIONS ANO is a dual unit commercial nuclear power plant that achieved initial criticality in 1974 on Unit 1 and 1978 on Unit 2. The plant is in Russellville, AR, a town of approximately 30,000 people.

ANO 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 ODCM and site procedures. Required sampling, analysis frequencies and location of sample collected are captured in the following tables and figures:

Table 1, Radiological Environmental Monitoring Program - Direct Radiation Table 2, Radiological Environmental Monitoring Program - Airborne Table 3, Radiological Environmental Monitoring Program - Waterborne Table 4, Radiological Environmental Monitoring Program - Ingestion Table 5, REMP Sampling Locations - Direct Radiation Figure 2, REMP Sample Locations (Near Field/Site Boundary)

Figure 3, REMP Sample Locations (Far Field)

Figure 4, REMP Sample Locations (Onsite)

Annual Radiological Environmental Operating Report YEAR: 2024 Page 8 of 61 Company: Entergy Plant: Arkansas Nuclear One 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 24 Routine monitoring stations with two or more dosimeters placed as follows:

An inner ring of stations, one in each compass sector in the general area of the site boundary.

An outer ring of stations, one in each compass sector at approximately 5 miles from the site; and Special interest areas, such as population centers, nearby recreation areas, and control stations See Table 5 Quarterly gamma dose/Quarterly

Annual Radiological Environmental Operating Report YEAR: 2024 Page 9 of 61 Company: Entergy Plant: Arkansas Nuclear One 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:

Three locations close to the site boundary in different sectors of the highest calculated annual average ground level D/Q.

One sample from the vicinity of a community having the highest calculated annual average D/Q.

One sample from a Control Location, approximately 10 to 20 miles away in the least predominant wind direction.

Station 2 (243° - 0.5 miles) - South of the sewage treatment plant.

Station 56 (264° - 0.4 miles) - West end of the sewage treatment plant.

Station 1 (88° - 0.5 miles) - Near the meteorology tower.

Station 6 (111° - 6.8 miles) - Local Entergy office, 305 South Knoxville Avenue, Russellville Station 7 (210° - 19.0 miles) -

Entergy Supply Yard on Highway 10 in Danville. (Control)

Continuous sampler operation with sample collection bi-weekly.

Particulate sampler: Analyze for gross beta radioactivity 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following filter change /

Bi-weekly. Perform gamma isotopic analysis on each sample when gross beta activity is >

10 times the yearly mean of control samples.

Radioiodine canister: Iodine (I)-131 analysis/Bi-weekly.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 10 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 3, Radiological Environmental Monitoring Program - Waterborne Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses Surface Water One sample upstream (control) and one sample downstream (indicator)

Station 8 (166° - 0.2 miles) - Plant discharge canal.

Station 10 (95° - 0.5 miles) - Plant intake canal.

Composite sample over one-month period; samples from monthly composites are combined to form quarterly composite samples to be analyzed for tritium (H-3).

Gamma isotopic analysis and tritium analysis quarterly.

Drinking Water One sample upstream (control) and one sample downstream (indicator)

Station 14 (70° - 5.1 miles) - Russellville city water system from the Illinois Bayou.

Station 57 (208° - 19.5 miles) - Danville public water supply treatment on Fifth Street.

Once per 92 days.

I-131, gross beta, gamma isotopic and tritium analyses once per 92 days.

Groundwater Two control location upgradient from the plant and Two indicator locations down gradient from the plant, only if likely to be affected.

Station 58 (GWM-1, 22° - 0.3 miles) - North of Protected Area (PA) in Owner Control Area (OCA). West of Security North Check Point, east side of access road.

Station 62 (GWM-101, 34° - 0.5 miles) -

North of PA in OCA. East of outside receiving building.

Station 63 (GWM-103, 206° - 0.1 miles) -

South of PA in OCA. North-east of Stator Rewind Bldg. near wood line.

Station 64 (GWM-13, 112° - 0.1 miles) -

South of Oily Water Separator facility, northwest corner of Unit 2 Intake Structure.

Inside PA.

Grab samples every 92 days.

Gamma isotopic, gross beta, and tritium analysis quarterly.

Sediment from Shoreline One sample upstream (control) and one sample downstream (indicator)

Station 8 (243° - 0.9 miles) - Plant discharge canal.

Station 16 (305° - 7.0 miles) - Big Piney Creek, located on the north side of the Arkansas River near the mouth of Piney Creek inland to Piney Bay.

Once per 365 days.

Gamma isotopic analysis annually.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 11 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 4, Radiological Environmental Monitoring Program - Ingestion Requirement Sample Location Description, Distance, and Direction Sampling Collection/

Frequency Type and Frequency of Analyses Fish and Invertebrates:

1 of sample of each commercially and recreationally important species in vicinity of site discharge.

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

Station 8 (212° - 0.5 miles) - Plant discharge canal.

Station 16 (305° - 7.0 miles) - Big Piney Creek, located on the north side of the Arkansas River near the mouth of Piney Creek inland to Piney Bay.

Once per 365 days.

Gamma isotopic analysis on edible portions annually Food Products:

Broad leaf vegetation grown nearest offsite locations of highest predicated annual average ground level D/Q if milk sampling is not performed and 1 sample collected from the control location.

Station 13 (273° - 0.5 miles) - West from ANO toward Gate 4 onto Flatwood Road.

Station 55 (217° - 13.1 miles) - Ozark National Forest north of Danville Three per 365 days.

Gamma. isotopic and I-131 analyses three times per 365 days

Annual Radiological Environmental Operating Report YEAR: 2024 Page 12 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 5, REMP Sampling Locations - Direct Radiation Site #

Location Type Sector Distance (miles) 1 Inner Ring E

0.5 2

Inner Ring WSW 0.5 3

Inner Ring N

0.7 4

Inner Ring S

0.5 56 Inner Ring W

0.4 108 Inner Ring NW 0.9 109 Inner Ring WNW 0.6 110 Inner Ring SE 0.8 145 Inner Ring NNE 0.6 146 Inner Ring NE 0.6 147 Inner Ring ENE 0.6 148 Inner Ring ESE 0.6 149 Inner Ring SSE 0.5 150 Inner Ring SSW 0.6 151 Inner Ring SW 0.4 152 Inner Ring NNW 0.8

Annual Radiological Environmental Operating Report YEAR: 2024 Page 13 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 5, REMP Sampling Locations - Direct Radiation Site #

Location Type Sector Distance (miles) 6 Special Interest ESE 6.8 111 Special Interest ESE 2.0 116 Special Interest NW 1.8 125 Special Interest NE 8.7 127 Special Interest E

5.2 137 Special Interest SSE 8.2 153 Special Interest NW 9.2 7

Control SSW 19.0

Annual Radiological Environmental Operating Report YEAR: 2024 Page 14 of 61 Company: Entergy Plant: Arkansas Nuclear One 6.0 MAPS OF COLLECTION SITES Figure 2, REMP Sample Locations (Near Field/Site Boundary)

Annual Radiological Environmental Operating Report YEAR: 2024 Page 15 of 61 Company: Entergy Plant: Arkansas Nuclear One Figure 3, REMP Sample Locations (Far Field)

Annual Radiological Environmental Operating Report YEAR: 2024 Page 16 of 61 Company: Entergy Plant: Arkansas Nuclear One Figure 4, REMP Sample Locations (Onsite)

Annual Radiological Environmental Operating Report YEAR: 2024 Page 17 of 61 Company: Entergy Plant: Arkansas Nuclear One 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)

Manganese (Mn)-54 1,000 30,000 Iron (Fe)-59 400 10,000 Cobalt (Co)-58 1,000 30,000 Co-60 300 10,000 Zinc (Zn)-65 300 20,000 Zirconium (Zr)-

Niobium (Nb)-95 400 I-131 2 (2) 0.9 3

100 Cesium (Cs)-134 30 10 1,000 60 1,000 Cs-137 50 20 2,000 70 2,000 Barium (Ba)-

Lanthanum (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-Nb-95 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-La-140 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

Annual Radiological Environmental Operating Report YEAR: 2024 Page 18 of 61 Company: Entergy Plant: Arkansas Nuclear One 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. Cs-137 can be routinely found in environmental samples as a results 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 ANO reports measured dose as net exposure (field reading less transit reading) normalized to 92 days and relies on comparison of the indicator locations to the control as a measure of plant impact. ANOs comparison of the inner ring and special interest area TLD results to the control, as seen in Table 21-23, identified no noticeable trend that would indicate that the ambient radiation levels are being affected by plant operations. Overall, ANO concluded that the ambient radiation levels are not being affected by plant operations.

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 140 samples were collected and analyzed for gross beta 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 bi-weekly. Radioiodine (I-131) analysis is performed bi-weekly on radioiodine sample cartridges.

All air particulate and radioiodine samples were below detection limit.

Indicator gross beta air particulate results for 2024 were comparable to results obtained from 2014-2023 of the operational REMP. Also, the 2024 gross beta annual average was less than the average for preoperational levels.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 19 of 61 Company: Entergy Plant: Arkansas Nuclear One Figure 5, Air Particulate: Analysis for Gross Beta, Average for All Indicator and Control Locations Monitoring Period Result (rem) 2014 - 2023 (Minimum Value) 0.017 2024 Average Value 0.023 2014 - 2023 (Maximum Value) 0.040 Preoperational 0.050 Air particulate and radioiodine results from this monitoring period, 2024, were compared to preoperational data and 10-year average as shown in Figure 5, and there were no significant changes.

In the absence of plant-related gamma radionuclides, gross beta activity is attributed to naturally occurring radionuclides, Table 10: Air Particulate Data Summary Tables (Gross Beta - pCi/m3) includes gross beta concentrations and provides a comparison of the indicator and control means and ranges emphasizes the consistent trends seen in this pathway to support the presence of naturally occurring activity. Therefore, it can be concluded that the airborne pathway continues to be unaffected by ANO operations.

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. 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. Positive detections of tritium were seen during the 2nd, 3rd, and 4th surface lake water sampling events. These positive detections align with plant effluent discharges. Tritium concentrations in surface water were well below the EPA tritium drinking water limit of 20,000 pCi/L.

Figure 6: Surface Water Tritium Results Monitoring Period Result 2014 - 2023 (Minimum Value) 671.3 2024 Value*

758.7 2014 - 2023 (Maximum Value) 932.3 Preoperational 200.0

Annual Radiological Environmental Operating Report YEAR: 2024 Page 20 of 61 Company: Entergy Plant: Arkansas Nuclear One 8.3.2 REMP Groundwater Groundwater samples were collected from control location upgradient from the plant and indicator location down gradient from the plant quarterly. During the calendar year 2024, a total of 16 groundwater water samples were collected from monitoring wells and analyzed in accordance with the requirements in the ODCM and shown in Table 3, Radiological Environmental Monitoring Program - Waterborne. A total of 8 control samples and a total of 8 indicator samples were collected. These samples were analyzed for tritium and gamma quarterly.

Groundwater is collected by peristaltic pumping or HydraSleeves. Pumping requires removing three volumes of water from the well (purging) before collecting samples.

Once purging is complete, pumping of water out of the well is equilibrated with water coming into the well. Once this equilibrium is obtained, representative samples of the groundwater table are collected. The HydraSleeve is classified as a no-purge (passive) grab sampling device, meaning that it is used to collect ground-water samples directly from the screened interval of a well without having to purge the well prior to sample collection. When it is used as described in this Standard Operating Procedure (SOP), the HydraSleeve causes no drawdown in the well (until the sample is withdrawn from the water column) and only minimal disturbance of the water column, because it has a very thin cross section, and it displaces very little water

(<100 ml) during deployment in the well. The HydraSleeve collects a sample from within the screen only, and it excludes water from any other part of the water column in the well using a self-sealing check valve at the top of the sampler. It is a single-use sampler that is not intended for reuse, so there are no decontamination requirements for the sampler itself.

Tritium and gamma concentrations were below the LLD limits at all four locations.

Listed below is a comparison of 2024 indicator results to past operational years.

Results are reported as annual average pCi/L. REMP Groundwater data are captured in the table below. During 2024 both control and indicator locations showed positive detection of gross beta. Gross beta activity is attributed to naturally occurring radionuclides. Table 19, Groundwater - Gamma and Iodine includes gross beta concentrations and provides a comparison of the indicator and control means and ranges emphasizes the consistent trends seen in this pathway to support the presence of naturally occurring activity. Therefore, it can be concluded that the groundwater pathway continues to be unaffected by ANO operations.

Figure 7: REMP Groundwater Tritium Sample Results Radionuclide 2024 2014 - 2023 Iodine-131

< LLD

< LLD Gamma

< LLD

< LLD Tritium

< LLD

< LLD Gross Beta 4.65*

3.93**

Average for Indicator and control wells for 2024.

- Only 2014-2023 gross beta average of indicator and control well data were used for review as historical data.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 21 of 61 Company: Entergy Plant: Arkansas Nuclear One The REMP groundwater program is part of the larger Groundwater Protection Program (GWPP) at ANO. The purpose of the GWPP is to ensure ANO is not contaminating the groundwater table around the site. In 2024, ANO released 440 gallons of radioactive water from the Unit 1 Borated Water Storage Tank (BWST) to the environment. As a result, the earthen surface and groundwater table around the BWST were contaminated with tritium and gamma isotopes. As a result, ANO installed a new groundwater monitoring well that was downgradient of the spill to monitor release of radioactive water to Lake Dardanelle. Also, ANO increased monitoring of groundwater in the affected and adjacent areas. This was considered an abnormal release, an unplanned or uncontrolled release of radioactive material into the environment. The remediation plan included removal of the top two feet of soil which was excavated from the spill area and was containerized for shipment and sent for disposal.

The excavated area was capped with concrete upon completion of soil excavation/remediation. Rain events during remediation washed radioactive isotopes out of plant stormwater drains to Lake Dardanelle with all releases related to the spill were captured and quantified in ANOs 2024 Annual Radioactive Effluent Release Report.

8.3.3 Drinking Water A total of 8 drinking water samples were obtained in 2024. Samples were collected from two locations (indicator and control). Although ANO personnel utilize Station 14 (City of Russellville) as an indicator location due to the potential for the drinking water pathway to exist, the City of Russellville has not withdrawn water from Lake Dardanelle in the past several years.

Drinking water samples were analyzed for gross beta radionuclides, I-131, gamma radionuclides and tritium. Gamma radionuclides, gross beta radionuclides, I-131, and tritium concentrations were below the LLD limits at the indicator and control locations, which is consistent with the preoperational and operational years as shown below.

Results from 2024 are summarized in table below. Results are reported as annual average pCi/L. The indicator location has historically shown gross beta above MDC but less than LLD, while the control location is below MDC and LLD. However, in 2024 the third quarter samples at the indicator were 2.60 pCi/L. This is above MDC but less than LLD. The value for gross beta at the control location for the first and third quarters in 2024 was 3.77 and 3.57 pCi/L, respectively, which was greater than MDC but less than LLD.

Figure 8: Drinking Water Gross Beta Samples Control vs. Indicator Comparison Radionuclide 2024 2014 - 2023*

Preoperational Gross Beta 3.14 3.94 2.0 Iodine-131

< LLD

< LLD Gamma

< LLD

< LLD Tritium

< LLD

< LLD 200.0

Average of the control and indicator results from the years 2014-2023.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 22 of 61 Company: Entergy Plant: Arkansas Nuclear One 8.3.4 Sediment from Shoreline Shoreline sediment collections were made in May 2024 and analyzed for gamma-emitting isotopes. Samples are collected at both indicator and control locations. A total of 2 shoreline samples were analyzed in accordance with requirements in the ODCM and shown in Table 3, Radiological Environmental Monitoring Program -

Waterborne. Although Cs-137 has been detected in years prior to 2023, all gamma radionuclides from 2024 samples were below detectable limits. These results are consistent with previous years results. Therefore, ANO operations had no significant impact on the environment or public by this waterborne pathway.

8.4 Ingestion Pathway Sample Results 8.4.1 Milk Milk samples were not collected during 2024 due to the unavailability of indicator locations within five miles of ANO. Due to the unavailability of an indication location, no control samples (greater than 5 miles from ANO) were collected.

8.4.2 Fish and Invertebrates Fish samples were collected from two locations and analyzed for gamma radionuclides. In 2024, gamma radionuclides were below detectable limits which are consistent with the preoperational monitoring period and operational results since 1997. 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.

Based on these analyses, ANO operations had no significant radiological impact upon the environment or public by this ingestion.

8.4.3 Leafy Vegetation In accordance with the ODCM and as described in Table 4, Radiological Environmental Monitoring Program - Ingestion, 6 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 and I-131 from the indicator and control locations monthly during growing season.

2024 levels remained undetectable, as has been the case in previous years.

Therefore, based on these measurements, ANO operations had no significant radiological impact upon the environment or public by this ingestion pathway.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 23 of 61 Company: Entergy Plant: Arkansas Nuclear One 9.0 LAND USE CENSUS A bi-annual land use census is required by the ODCM 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 [2].

NUREG-1301/1302 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.

For elevated releases the Land Use Census shall also identify within a distance of 5 km (3 miles) the locations in each of the 16 meteorological sectors of all milk animals and all gardens of greater than 50 m2 producing broad leaf vegetation."

Note, per NUREG-1301/1302, 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. In summary, the highest D/Q locations for nearest garden, nearest residence and nearest milk animal did not change following the 2024 census.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 24 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 8: Land Use Census - Nearest Receptors within 5 miles Sector Direction Nearest Residence (Miles)

Nearest Milk Animal (Miles)

Nearest Garden (Miles)

A N

1.0

> 5 N/A B

NNE 1.2

> 5 N/A C

NE 0.9

> 5 N/A D

ENE 0.8

> 5 N/A E

E 0.8

> 5 N/A F

ESE 0.8

> 5 N/A G

SE 0.8

> 5 N/A H

SSE 0.8

> 5 N/A J

S 0.8

> 5 N/A K

SSW 0.7

> 5 N/A L

SW 2.8

> 5 N/A M

WSW 0.7

> 5 N/A N

W 0.8

> 5 N/A P

WNW 0.8

> 5 N/A Q

NW 1.0

> 5 4.2 R

NNW 0.9

> 5 N/A There was one commercial garden found in a five (5) mile radius of the plant which is Renees Berry Garden. This garden is exclusively strawberries and blackberries which do not meet the definition of broadleaf vegetation as described in the NRC Branch Technical Position (BTP).

10.0 SAMPLE DEVIATIONS, ANOMALIES AND UNAVAILABILITY Sampling and analysis are performed for media types addressed in the ODCM.

Sampling and analysis challenges may be experienced due to a multitude of reasons including environmental factors, loss of TLDs/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 prevents the sample from being analyzed as it normally would or may have altered the outcome of the analysis (i.e., cross contamination, human error).

Annual Radiological Environmental Operating Report YEAR: 2024 Page 25 of 61 Company: Entergy Plant: Arkansas Nuclear One "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 except for the following:

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 Deviation -

Air 1

01/11/2024 Pinhole in air filter Pinholes develop in filters periodically due to environmental conditions. Filter still loaded particulate, and no issues identified with analysis Deviation -

Air 2

01/24/2024 Pinhole in air filter Pinholes develop in filters periodically due to environmental conditions. Filter still loaded particulate, and no issues identified with analysis.

Deviation -

Air 2 and 56 08/28/2024 Loss of line power Remote monitoring installed to mitigate loss of run time.

Deviation -

Air 2 and 56 10/22/2024 Loss of line power Remote monitoring installed to mitigate loss of run time.

Deviation -

Air 2

11/06/2024 Pump failure Routine maintenance Deviation -

Air 1

12/03/2024 Pump Failure Routine Maintenance Deviation -

Air 2 and 56 12/31/2024 Loss of line power Remote monitoring installed to mitigate loss of run time.

11.0 OTHER SUPPLEMENTAL INFORMATION 11.1 NEI 07-07 Onsite Radiological Groundwater Monitoring Program ANO 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, samples and results taken in support of NEI 07-07 on-site groundwater monitoring program are separate from the REMP. Results of the NEI 07-07 Radiological Groundwater Monitoring Program for onsite groundwater wells are provided in the ARERR.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 26 of 61 Company: Entergy Plant: Arkansas Nuclear One 11.2 Program Modifications There was one revision made to ANO REMP Procedure, EN-CY-130-01, in 2024.

Revision 7 clarified some procedure steps to help with place keeping, updated verbiage to be clearer and more concise, and updated Section 7.9 name to Post Accident Environmental Sampling.

11.3 Corrections to Previous Reports None.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 27 of 61 Company: Entergy Plant: Arkansas Nuclear One 12.0 BIBLIOGRAPHY

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

National Council on Radiation Protection, Bethesda, 2009.

[2] "10 CFR 50, "Domestic Licensing of Production and Utilization Facilities"," US Nuclear Regulatory Commission, Washington, DC.

[3] "Regulatory Guide 4.1, "Radiological Environmental Monitoring for Nuclear Power Plants",

Revision 2," Nuclear Regulatory Commission, 2009.

[4] "NUREG-1301, Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Pressurized Water Reactors,.," Nuclear Regulatory Commission, April 1991.

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

[6] "Branch Technical Position, Revision 1," NRC000096, Submitted March 30, 2012, November 1979.

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

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

[8] "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.

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

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

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

Nuclear Regulatory Commission, 1974.

[12] "Ionizing Radiation Exposure of the Population of the United States," Bethesda, MD, 2009.

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

[14] "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.

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

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

Nuclear Regulatory Commission, 1987.

[17] "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.

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

[19] "NEI 07-07, Industry Ground Water Protection InitiativeFinal Guidance Document,," Nuclear Energy Institute, Washington, D.C..

Annual Radiological Environmental Operating Report YEAR: 2024 Page 28 of 61 Company: Entergy Plant: Arkansas Nuclear One

[20] "ANSI 13.37, Environmental Dosimetry-Criteria for System Design and Implementation," Health Physics Society (HPS), May, 2019.

[21] "40 CFR Part 141, National Primary Drinking Water Regulations,," US Environmental Protection Agency, Washington, DC..

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

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

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

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

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

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

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

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

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

Nuclear Regulatory Commission, 1987.

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

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

[31] "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.

[32] "10 CFR 50 - Domestic Licensing of Production and Utilization Facilities," US Nuclear Regulatory Commission, Washington, DC.

[33] "40 CFR 190 - Environmental Radiation Protection Standards for Nuclear Power Operation," US Environmental Protection Agency, Washington, DC.

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

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

National Council on Radiation Protection and Measurements, Bethesda, MD, 2009.

[36] "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.

[37] "40 CFR 141 - National Primary Drinking Water Regulations," US Environmental Protection Agency, Washington, DC..

[38] "10 CFR 20 - Standards for Protection Against Radiation," US Nuclear Regulatory Commission, Washington, DC.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 29 of 61 Company: Entergy Plant: Arkansas Nuclear One

, Data Table Summary Medium or Pathway Sampled (Units)

Type, Total Number of Analyses performed5 Lower Limit of Detection (LLD)6 Indicator Mean7 (F)

Range Location with Highest Annual Mean8 Control Mean7 (F)

Range Number of Nonroutine Reported Measurements9 Name Distance and Direction Mean7 (F)

Range Air Particulates (pCi/m3)

GB/135 0.01 2.28E-02 0.0209-0.0255 Station 56 264°, 0.4 mi 2.55E-02 2.26E-02 0.0218-0.0234 0

Airborne Radioiodine (pCi/m3)

I-131/135 0.07

< LLD N/A N/A

< LLD 0

Milk (pCi/L)

N/A N/A N/A N/A N/A N/A 0

Vegetation (pCi/kg-wet)

I-131 / 6 GS / 6 Cs-134 Cs-137 60 60 80

< LLD N/A N/A N/A N/A N/A N/A N/A 0

0 0

5 GB = Gross beta; GS = Gamma scan; H-3 = Tritium: Mn-54 = Manganese-54; Fe-59 = Iron-59; Co-58 = Cobalt-58; Zn-65 = Zinc-65; Zr-95 =

Zirconium-95; Nb-95 = Niobium-95; Ba-140 = Barium-140; and La-140 = Lanthanum-140.

6 LLD = Required lower limit of detection based on ANO Units 1 and 2 ODCM Table 2.5-1.

7 Mean and range based upon detectable measurements only. Fraction of detectable measurements at specified locations is indicated in parenthesis (F) 8 Locations are specified (1) by name and (2) degrees relative to reactor site.

9 Non-routine results are those which exceed ten times the control station value. If no control station value is available, the result is considered non-routine if it exceeds ten times the preoperational value for the location.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 30 of 61 Company: Entergy Plant: Arkansas Nuclear One Medium or Pathway Sampled (Units)

Type, Total Number of Analyses performed5 Lower Limit of Detection (LLD)6 Indicator Mean7 (F)

Range Location with Highest Annual Mean8 Control Mean7 (F)

Range Number of Nonroutine Reported Measurements9 Name Distance and Direction Mean7 (F)

Range Surface Water (pCi/L)

Tritium (H-3 / 8 GS / 24 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Zr-95 Nb-95 I-131 Cs-134 Cs-137 Ba-140 La-140 3000 15 30 15 15 30 30 15 15 15 18 60 15 758.7 409-1230 Station 8 166°, 0.2 mi 758.7 (4 / 4)

[409 - 1230]

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A

< LLD

< LLD 0

0 0

Annual Radiological Environmental Operating Report YEAR: 2024 Page 31 of 61 Company: Entergy Plant: Arkansas Nuclear One Medium or Pathway Sampled (Units)

Type, Total Number of Analyses performed5 Lower Limit of Detection (LLD)6 Indicator Mean7 (F)

Range Location with Highest Annual Mean8 Control Mean7 (F)

Range Number of Nonroutine Reported Measurements9 Name Distance and Direction Mean7 (F)

Range Drinking Water (pCi/L)

GB / 8 I-131 / 8 H-3 / 8 GS / 8 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Zr-95 Nb-95 Cs-134 Cs-137 Ba-140 La-140 4

1 2000 15 30 15 15 30 30 15 15 18 60 15 2.60

< LLD - 2.6

< LLD

< LLD Station 57 208°, 19.5 mi

< LLD

< LLD 3.67 (4 / 4)

[3.57 - 3.77]

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 3.67 (4 / 4)

[3.57 - 3.77]

< LLD

< LLD 0

0 0

0 Fish (pCi/kg-wet)

GS / 2 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Cs-134 Cs-137 130 260 130 130 260 130 150

< LLD

< LLD N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A

< LLD

< LLD 0

0 0

Annual Radiological Environmental Operating Report YEAR: 2024 Page 32 of 61 Company: Entergy Plant: Arkansas Nuclear One Medium or Pathway Sampled (Units)

Type, Total Number of Analyses performed5 Lower Limit of Detection (LLD)6 Indicator Mean7 (F)

Range Location with Highest Annual Mean8 Control Mean7 (F)

Range Number of Nonroutine Reported Measurements9 Name Distance and Direction Mean7 (F)

Range Sediment (pCi/kg-dry)

GS / 2 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Cs-134 Cs-137 130 260 130 130 260 130 150

< LLD

< LLD N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A

< LLD

< LLD 0

0 0

Annual Radiological Environmental Operating Report YEAR: 2024 Page 33 of 61 Company: Entergy Plant: Arkansas Nuclear One

, Complete Data Table for All Analysis Results Obtained In 2024 Table 10: Air Particulate Data Summary Tables (Gross Beta - pCi/m3)

Date/ Sample ID Station 1 Station 2 Station 56 Station 6 Station 7 1/11/2024 2.41E-02 2.67E-02 4.65E-02 2.69E-02 3.52E-02 1/23/2024 2.48E-02 2.66E-02 4.17E-02 2.86E-02 2.87E-02 1/30/2024 1.19E-02 1.49E-02 1.99E-02 1.70E-02 1.46E-02 2/13/2024 1.90E-02 1.56E-02 3.14E-02 2.15E-02 2.03E-02 2/28/2024 2.34E-02 2.02E-02 2.38E-02 2.32E-02 2.34E-02 3/12/2024 1.22E-02 1.47E-02 2.67E-02 1.77E-02 1.74E-02 3/26/2024 2.03E-02 1.78E-02 2.55E-02 1.76E-02 1.67E-02 4/9/2024 1.87E-02 1.68E-02 2.25E-02 2.09E-02 1.67E-02 4/23/2024 1.47E-02 1.32E-02 2.17E-02 1.65E-02 1.84E-02 5/7/2024 1.59E-02 1.42E-02 2.35E-02 1.68E-02 1.98E-02 5/21/2024 2.09E-02 1.92E-02 1.73E-02 1.70E-02 2.14E-02 6/4/2024 1.87E-02 1.59E-02 1.71E-02 1.73E-02 1.70E-02 6/18/2024 2.16E-02 1.79E-02 1.92E-02 2.04E-02 2.05E-02 7/2/2024 1.91E-02 1.80E-02 1.73E-02 2.84E-02 1.79E-02 7/16/2024 2.09E-02 1.80E-02 2.08E-02 2.17E-02 2.10E-02 7/30/2024 1.47E-02 1.47E-02 1.36E-02 1.35E-02 1.55E-02 8/13/2024 2.77E-02 2.55E-02 2.49E-02 2.29E-02 2.89E-02 8/27/2024 2.66E-02 2.15E-02 2.07E-02 2.54E-02 2.57E-02 9/10/2024 1.98E-02 1.97E-02 1.97E-02 1.55E-02 2.18E-02 9/24/2024 2.51E-02 2.17E-02 2.16E-02 1.98E-02 2.51E-02 10/8/2024 2.71E-02 2.67E-02 2.74E-02 2.51E-02 3.10E-02 10/22/2024 3.20E-02 2.52E-02 2.90E-02 2.48E-02 2.82E-02 11/5/2024 3.06E-02 2.38E-02 3.10E-02 2.62E-02 3.04E-02 11/19/2024 2.62E-02 3.33E-02 2.80E-02 2.03E-02 3.06E-02 12/3/2024 2.94E-02 3.71E-02 3.71E-02 3.73E-02 2.93E-02 12/17/2024 2.56E-02 2.41E-02 2.24E-02 2.33E-02 2.87E-02 12/31/2024 2.99E-02 2.89E-02 3.01E-02 2.75E-02 3.33E-02

Annual Radiological Environmental Operating Report YEAR: 2024 Page 34 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 11: Air Particulate Data Summary Tables (I-131 - pCi/m3)

Date/ Sample ID Station 1 Station 2 Station 6 Station 7 Station 56 1/11/2024

< 3.45E-02

< 3.44E-02

< 1.64E-02 1/23/2024

< 1.81E-02

< 1.80E-02

< 1.38E-02 1/30/2024

< 2.57E-02

< 2.85E-02

< 2.57E-02

< 2.58E-02 2/13/2024

< 1.88E-02

< 7.88E-03

< 1.88E-02

< 1.89E-02 2/28/2024

< 2.17E-02

< 2.19E-02

< 9.15E-03

< 2.19E-02 3/12/2024

< 8.71E-03

< 2.07E-02

< 2.06E-02

< 2.05E-02

< 2.07E-02 3/26/2024

< 3.96E-02

< 1.64E-02

< 3.93E-02

< 3.97E-02 4/9/2024

< 1.78E-02

< 1.77E-02

< 1.36E-02 4/23/2024

< 1.46E-02

< 1.45E-02

< 6.13E-03 5/7/2024

< 2.18E-02

< 2.19E-02

< 2.16E-02

< 2.17E-02

< 9.19E-03 5/21/2024

< 1.38E-02

< 1.37E-02

< 1.05E-02 6/4/2024

< 1.45E-02

< 9.73E-03

< 1.45E-02

< 1.44E-02

< 1.46E-02 6/18/2024

< 2.21E-02

< 9.25E-03

< 2.20E-02

< 2.21E-02 7/2/2024

< 3.42E-02

< 1.44E-02

< 3.41E-02

< 3.39E-02

< 3.42E-02 7/16/2024

< 2.22E-02

< 2.21E-02

< 1.12E-02

< 2.22E-02 7/30/2024

< 1.54E-02

< 2.02E-02

< 2.01E-02

< 2.02E-02 8/13/2024

< 1.90E-02

< 1.91E-02

< 1.89E-02

< 2.11E-02 8/27/2024

< 1.47E-02

< 1.12E-02

< 1.47E-02

< 1.47E-02 9/10/2024

< 2.56E-02

< 2.57E-02

< 2.56E-02

< 2.55E-02

< 1.96E-02 9/24/2024

< 1.46E-02

< 6.93E-03

< 1.45E-02

< 1.46E-02 10/8/2024

< 1.45E-02

< 1.91E-02

< 1.90E-02

< 1.91E-02 10/22/2024

< 1.58E-02

< 1.60E-02

< 1.58E-02

< 1.57E-02

< 8.72E-03 11/5/2024

< 2.17E-02

< 2.16E-02

< 2.15E-02

< 1.58E-02 11/19/2024

< 2.12E-02

< 2.11E-02

< 1.52E-02

< 2.12E-02 12/3/2024

< 2.67E-02

< 2.65E-02

< 1.37E-02 12/17/2024

< 9.37E-03

< 1.97E-02

< 1.96E-02

< 1.97E-02 12/31/2024

< 3.42E-02

< 3.50E-02

< 3.41E-02

< 3.40E-02

< 2.67E-02

Annual Radiological Environmental Operating Report YEAR: 2024 Page 35 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 12, Surface Water - Gamma Analysis: Gamma Isotopic Units: pCi/L Location Start Date End Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD 15 15 30 15 30 15 30 15 15 18 60 15 Station 8 (Indicator) 12/31/2023 01/31/2024

< 1.68

< 1.89

< 5.00

< 1.80

< 3.53

< 2.15

< 3.63

< 10.3

< 1.90

< 1.89

< 19.2

< 7.17 Station 10 (Control) 12/31/2023 01/31/2024

< 4.78

< 4.82

< 9.33

< 4.69

< 10.5

< 4.69

< 8.30

< 8.93

< 5.78

< 5.15

< 23.0

< 9.45 Station 8 (Indicator) 01/31/2024 02/29/2024

< 1.65

< 2.00

< 4.13

< 2.01

< 3.64

< 1.89

< 2.96

< 10.2

< 1.75

< 1.64

< 15.7

< 5.84 Station 10 (Control) 01/31/2024 02/29/2024

< 6.07

< 6.88

< 16.7

< 7.80

< 13.0

< 6.37

< 8.76

< 7.85

< 7.55

< 5.28

< 33.6

< 9.67 Station 8 (Indicator) 02/29/2024 03/31/2024

< 1.22

< 1.28

< 2.90

< 1.27

< 2.68

< 1.41

< 2.35

< 6.38

< 1.27

< 1.20

< 10.8

< 4.01 Station 10 (Control) 02/29/2024 03/31/2024

< 1.87

< 1.79

< 3.47

< 2.18

< 3.94

< 1.84

< 3.29

< 2.54

< 2.01

< 1.94

< 8.26

< 2.83 Station 8 (Indicator) 03/31/2024 04/30/2024

< 1.35

< 1.57

< 3.51

< 1.57

< 2.94

< 1.68

< 3.07

< 9.03

< 1.52

< 1.51

< 16.0

< 5.47 Station 10 (Control) 03/31/2024 04/30/2024

< 5.88

< 4.30

< 10.2

< 5.43

< 8.73

< 5.61

< 10.6

< 9.12

< 5.93

< 5.27

< 22.9

< 9.33 Station 8 (Indicator) 04/30/2024 05/31/2024

< 1.89

< 2.08

< 5.20

< 2.11

< 4.06

< 2.33

< 3.91

< 12.6

< 2.05

< 2.08

< 21.5

< 7.82 Station 10 (Control) 04/30/2024 05/31/2024

< 4.08

< 5.24

< 10.9

< 6.54

< 10.5

< 4.93

< 7.05

< 7.07

< 5.69

< 5.45

< 21.3

< 10.2

Annual Radiological Environmental Operating Report YEAR: 2024 Page 36 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 12, Surface Water - Gamma Analysis: Gamma Isotopic Units: pCi/L Location Start Date End Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 Station 8 (Indicator) 05/31/2024 06/30/2024

< 2.79

< 2.88

< 6.48

< 2.81

< 5.25

< 2.75

< 4.57

< 10.2

< 2.65

< 2.57

< 21.6

< 7.66 Station 10 (Control) 05/31/2024 06/30/2024

< 6.09

< 5.20

< 10.6

< 7.04

< 10.8

< 5.73

< 9.13

< 5.78

< 5.35

< 5.75

< 21.3

< 7.51 Station 8 (Indicator) 06/30/2024 07/31/2024

< 1.77

< 2.04

< 4.82

< 1.88

< 3.58

< 2.11

< 3.57

< 11.7

< 1.93

< 1.69

< 26.0

< 9.79 Station 10 (Control) 06/30/2024 07/31/2024

< 4.30

< 4.32

< 10.9

< 3.97

< 8.77

< 5.60

< 9.18

< 12.6

< 4.86

< 4.97

< 32.8

< 12.1 Station 8 (Indicator) 07/31/2024 08/31/2024

< 1.46

< 1.73

< 4.08

< 1.67

< 3.38

< 1.91

< 3.20

< 9.66

< 1.77

< 1.64

< 15.9

< 5.82 Station 10 (Control) 07/31/2024 08/31/2024

< 7.25

< 8.07

< 18.1

< 9.13

< 19.0

< 8.91

< 16.8

< 12.0

< 10.4

< 9.20

< 42.2

< 13.8 Station 8 (Indicator) 08/31/2024 09/30/2024

< 1.41

< 1.53

< 3.34

< 1.51

< 3.04

< 1.49

< 2.58

< 6.82

< 1.35

< 1.36

< 12.4

< 4.47 Station 10 (Control) 08/31/2024 09/30/2024

< 1.72

< 1.63

< 3.60

< 1.82

< 3.24

< 1.82

< 3.21

< 2.90

< 2.04

< 1.81

< 7.96

< 3.20 Station 8 (Indicator) 09/30/2024 10/31/2024

< 1.32

< 1.53

< 3.35

< 1.62

< 2.64

< 1.53

< 2.79

< 8.48

< 1.42

< 1.40

< 15.1

< 5.37 Station 10 (Control) 09/30/2024 10/31/2024

< 4.44

< 5.17

< 14.7

< 6.16

< 11.9

< 5.78

< 10.2

< 9.75

< 7.02

< 4.91

< 26.8

< 6.20 Station 8 (Indicator) 10/31/2024 11/30/2024

< 1.30

< 1.42

< 3.48

< 1.65

< 2.87

< 1.63

< 2.76

< 10.3

< 1.28

< 1.41

< 15.3

< 5.42

Annual Radiological Environmental Operating Report YEAR: 2024 Page 37 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 12, Surface Water - Gamma Analysis: Gamma Isotopic Units: pCi/L Location Start Date End Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 Station 10 (Control) 10/31/2024 11/30/2024

< 5.22

< 7.74

< 14.9

< 4.54

< 17.2

< 6.68

< 11.0

< 10.8

< 7.15

< 6.33

< 37.4

< 6.19 Station 8 (Indicator) 11/30/2024 12/31/2024

< 1.38

< 1.73

< 3.71

< 1.69

< 2.85

< 1.58

< 2.95

< 10.9

< 1.45

< 1.42

< 17.0

< 6.22 Station 10 (Control) 11/30/2024 12/31/2024

< 4.32

< 6.21

< 10.8

< 4.24

< 9.24

< 4.62

< 7.03

< 10.9

< 4.85

< 4.63

< 24.7

< 7.33

Annual Radiological Environmental Operating Report YEAR: 2024 Page 38 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 13, Surface Water - Tritium Analysis: H-3 Units: pCi/L Location Start Date End Date H-3 REQUIRED LLD 3000 Station 8 (Indicator) 12/31/2023 03/31/2024

< 390 Station 10 (Control) 12/31/2023 03/31/2024

< 392 Station 8 (Indicator) 03/31/2024 06/30/2024 637 Station 10 (Control) 03/31/2024 06/30/2024

< 384 Station 8 (Indicator) 06/30/2024 09/30/2024 1230 Station 10 (Control) 06/30/2024 09/30/2024

< 284 Station 8 (Indicator) 09/30/2024 12/31/2024 409 Station 10 (Control) 09/30/2024 12/31/2024

< 348

Annual Radiological Environmental Operating Report YEAR: 2024 Page 39 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 14, Drinking Water -Gamma, GB, I-131 Analysis: Gamma Isotopic, Gross Beta, I-131 Units: pCi/L Location Collection Date Gross Beta Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD 4.0 15 15 30 15 30 15 30 1.0 15 18 60 15 Station 14 (Indicator) 1/23/2024

< 1.54

< 3.63

< 4.24

< 9.74

< 4.72

< 7.81

< 4.74

< 7.58

< 0.87

< 3.94

< 4.34

< 22.8

< 9.94 Station 57 (Control) 01/23/2024 3.77

< 4.22

< 4.40

< 8.12

< 3.79

< 7.21

< 4.19

< 8.06

< 0.86

< 4.71

< 4.08

< 18.5

< 7.01 Station 14 (Indicator) 4/23/2024

<1.68

< 4.90

< 5.47

< 10.6

< 7.51

< 12.7

< 6.49

< 10.5

< 0.80

< 5.57

< 5.41

< 27.2

<9.30 Station 57 (Control) 4/23/2024

< 1.80

< 6.29

< 5.22

< 12.4

< 7.03

< 11.1

< 6.31

< 10.3

< 0.88

< 6.14

< 5.63

< 24.4

< 10.6 Station 14 (Indicator) 7/10/2024 2.60

< 5.23

< 4.41

< 9.00

< 5.08

< 9.51

< 6.99

< 8.24

< 0.83

< 5.92

< 6.33

< 29.6

< 8.77 Station 57 (Control) 7/10/2024 3.57

< 4.69

< 4.84

< 6.93

< 4.60

< 9.23

< 4.27

< 8.35

< 0.79

< 4.72

< 4.12

< 20.5

< 8.36 Station 14 (Indicator) 10/15/2024

< 2.30

< 7.13

< 5.85

< 11.9

< 10.0

< 14.1

< 6.87

< 14.4

< 0.76

< 4.92

< 8.61

< 31.7

< 7.68 Station 57 (Control) 10/15/2024

< 2.59

< 7.52

< 8.00

< 16.4

< 5.49

< 15.3

< 6.46

< 12.0

< 0.87

< 6.79

< 7.36

< 26.4

< 8.15

Annual Radiological Environmental Operating Report YEAR: 2024 Page 40 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 15, Drinking Water - Tritium Analysis: H-3 Units: pCi/L Location Collection Date H-3 REQUIRED LLD 2000 Station 14 (Indicator) 1/23/2024

< 397 Station 57 (Control) 1/23/2024

< 363 Station 14 (Indicator) 4/23/2024

< 366 Station 57 (Control) 4/23/2024

< 370 Station 14 (Indicator) 7/10/2024

< 394 Station 57 (Control) 7/10/2024

< 392 Station 14 (Indicator) 10/15/2024

< 291 Station 57 (Control) 10/15/2024

< 293 Table 16, Fish Analysis: Gamma Isotopic Units: pCi/kg Location Collection Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Cs-134 Cs-137 REQUIRED LLD 130 130 260 130 260 130 150 Station 8 (Indicator) 2/15/2024

< 60.7

< 54.1

< 153

< 68.3

< 123

< 61.6

< 51.8 Station 16 (Control) 5/02/2024

< 81.8

< 73.3

< 153

< 97.1

< 176

< 78.8

< 75.7

Annual Radiological Environmental Operating Report YEAR: 2024 Page 41 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 17, Sediment Analysis: Gamma Isotopic Units: pCi/kg Location Collection Date Cs-134 Cs-137 REQUIRED LLD 150 180 Station 8 (Indicator) 04/13/2023

< 96.5

< 106 Station 16 (Control) 04/13/2023

< 65.8

< 62.7 Table 18, Food Products Analysis: I-131, Gamma Isotopic Units: pCi/kg Location Collection Date I-131 Cs-134 Cs-137 REQUIRED LLD 60 60 80 Station 13 (Indicator) 06/04/2024

< 34.8

< 38.3

< 30.0 Station 55 (Control) 06/04/2024

< 30.7

< 28.2

< 26.8 Station 13 (Indicator) 07/09/2024

< 51.0

< 22.7

< 21.6 Station 55 (Control) 07/09/2024

< 41.3

< 24.7

< 22.2 Station 13 (Indicator) 08/13/2024

< 35.7

< 30.7 Station 55 (Control) 08/13/2024

< 40.8

< 36.5

< 34.6

Annual Radiological Environmental Operating Report YEAR: 2024 Page 42 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 19, Groundwater - Gamma and Iodine Analysis: Gross Beta, I-131, Gamma Isotopic Units: pCi/L Location Collection Date Gr-B Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD N/A[Note 1]

15 15 30 15 30 15 30 15 15 18 60 15 Station 58 (Control) 3/07/2024 5.53

< 5.55

< 5.38

< 12.4

< 4.74

< 12.7

< 6.68

< 12.0

< 12.8

< 6.76

< 6.59

< 33.0

< 14.7 Station 62 (Control) 3/06/2024

< 3.32

< 1.74

< 1.87

< 3.81

< 1.96

< 3.68

< 1.79

< 3.19

< 4.14

< 1.97

< 1.98

< 10.2

< 3.39 Station 63 (Indicator) 3/06/2024 5.05

< 1.75

< 1.86

< 4.62

< 2.17

< 4.13

< 2.14

< 3.59

< 3.99

< 2.21

< 2.12

< 10.4

< 3.63 Station 64 (Indicator) 3/07/2024

<1.92

< 6.01

< 5.90

< 8.14

< 6.55

< 8.77

< 6.91

< 9.32

< 11.2

< 5.76

< 4.97

< 29.3

< 11.0 Station 58 (Control) 6/11/2024

< 2.17

< 1.80

< 1.85

< 4.09

< 1.87

< 3.59

< 1.99

< 3.60

< 10.9

< 1.97

< 1.75

< 18.4

< 6.26 Station 62 (Control) 6/11/2024

< 3.61

< 1.13

< 1.29

< 3.11

< 1.39

< 2.45

< 1.47

< 2.27

< 7.81

< 1.29

< 1.18

< 12.4

< 4.84 Station 63 (Indicator) 6/11/2024

< 3.58

< 1.79

< 2.04

< 4.65

< 2.11

< 3.76

< 2.16

< 3.71

< 11.0

< 2.06

< 1.71

< 19.3

< 7.25 Station 64 (Indicator) 6/11/2024 2.85

< 5.46

< 5.78

< 9.87

< 4.82

< 11.3

< 5.50

< 7.53

< 8.65

< 6.69

< 6.03

< 22.4

< 9.12 Station 58 (Control) 9/10/2024

< 1.95

< 5.62

< 5.47

< 9.58

< 7.10

< 11.5

< 5.03

< 8.31

< 9.56

< 5.58

< 5.99

< 25.3

< 10.7 Station 62 (Control) 9/10/2024

< 3.22

< 5.53

< 5.40

< 10.7

< 6.94

< 10.3

< 5.11

< 12.1

< 11.4

< 5.71

< 6.21

< 30.5

< 10.6

Annual Radiological Environmental Operating Report YEAR: 2024 Page 43 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 19, Groundwater - Gamma and Iodine Analysis: Gross Beta, I-131, Gamma Isotopic Units: pCi/L Location Collection Date Gr-B Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD N/A[Note 1]

15 15 30 15 30 15 30 15 15 18 60 15 Station 63 (Indicator) 9/10/2024 5.19

< 5.19

< 5.14

< 10.4

< 5.33

< 8.18

< 5.13

< 9.71

< 9.22

< 5.02

< 4.88

< 25.7

< 8.69 Station 64 (Indicator) 9/11/2024

< 3.39

< 5.89

< 7.47

< 13.2

< 7.02

< 12.9

< 6.67

< 10.4

< 11.1

< 6.76

< 6.52

< 32.8

< 11.3 Station 58 (Control) 12/10/2024

< 2.12

< 3.22

< 3.73

< 7.11

< 4.44

< 7.28

< 3.59

< 6.39

< 6.31

< 3.29

< 3.35

< 16.0

< 7.33 Station 62 (Control) 12/10/2024

< 3.85

< 4.03

< 3.92

< 6.27

< 3.70

< 8.69

< 4.43

< 7.57

< 7.24

< 3.70

< 4.11

< 18.5

< 6.34 Station 63 (Indicator) 12/10/2024

< 3.95

< 5.02

< 5.12

< 9.96

< 4.33

< 11.3

< 5.02

< 8.66

< 9.42

< 4.78

< 5.31

< 25.5

< 8.10 Station 64 (Indicator) 12/11/2024

< 2.94

< 4.56

< 4.66

< 10.4

< 5.92

< 9.81

< 6.08

< 6.75

< 8.36

< 5.59

< 4.45

< 23.3

< 9.92

Annual Radiological Environmental Operating Report YEAR: 2024 Page 44 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 20, Groundwater - Tritium Analysis: H-3 Units: pCi/L Location Collection Date H-3 REQUIRED LLD 3000 Station 58 (Control) 3/07/2024

< 381 Station 62 (Control) 3/06/2024

< 388 Station 63 (Indicator) 3/06/2024

< 383 Station 64 (Indicator) 3/06/2024

< 379 Station 58 (Control) 6/11/2024

< 394 Station 62 (Control) 6/11/2024

< 385 Station 63 (Indicator) 6/11/2024

< 390 Station 64 (Indicator) 6/12/2024

< 392 Station 58 (Control) 9/10/2024

< 233 Station 62 (Control) 9/10/2024

< 246 Station 63 (Indicator) 9/10/2024

< 237 Station 64 (Indicator) 9/10/2024

< 236 Station 58 (Control) 12/10/2024

< 386 Station 62 (Control) 12/10/2024

< 389 Station 63 (Indicator) 12/10/2024

< 386 Station 64 (Indicator) 12/11/2024

< 389

Annual Radiological Environmental Operating Report YEAR: 2024 Page 45 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 21, Thermoluminescent Dosimeters - Inner Ring Analysis:

Gamma Dose Units: mRem Station 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Annual Mean 1

10.6 11.4 12.6 11.7 11.6 2

10.7 11.6 12.7 12.2 11.8 3

7.3 7.8 8.8 8.6 8.1 4

9.6 10.5 11.3 11.3 10.7 56[Note 1]

12.0 12.8 13.3 12.3 12.6 108 10.9 11.0 12.2 11.1 11.3 109 10.6 11.2 12.7 11.7 11.6 110 10.3 10.9 11.5 10.2 10.7 145 9.6 10.8 10.2 10.9 10.4 146 9.2 10.3 11.1 9.9 10.1 147 9.0 9.7 10.2 11.5 10.1 148 10.3 10.9 11.4 10.7 10.8 149 9.3 9.9 11.0 12.1 10.6 150 8.5 9.1 9.5 9.4 9.1 151 10.2 12.2 13.9 11.0 11.8 152 8.6 9.2 10.1 10.0 9.5

[Note 1] - Station with highest annual mean.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 46 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 22, Thermoluminescent Dosimeters - Special Interest Areas Analysis:

Gamma Dose Units: mrem Station 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Annual Mean 6

9.7 10.1 10.3 10.7 10.2 111 7.1 8.3 8.8 7.8 8.0 116 10.6 10.8 9.8 11.0 10.6 125 7.1 8.0 8.0 8.2 7.8 127 9.4 9.9 10.3 10.9 10.1 137[Note 1]

10.3 11.4 12.4 11.8 11.5 153 9.8 9.5 10.3 10.1 9.9

[Note 1] - Station with highest annual mean.

Table 23, Thermoluminescent Dosimeters - Control Location Analysis:

Gamma Dose Units: mrem Station 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Annual Mean 7

9.7 10.9 11.2 10.9 10.7

Annual Radiological Environmental Operating Report YEAR: 2024 Page 47 of 61 Company: Entergy Plant: Arkansas Nuclear One

, 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.

Teledyne Brown Engineering (TBE) participated in the following proficiency testing studies provided by Eckert & Ziegler Analytics in 2024. The Laboratorys intercomparison program results for 2024 are summarized below.

Environmental Dosimetry Company (EDC) participated in the following proficiency testing studies provided by EDC in 2024. The Laboratorys intercomparison program results for 2024 are summarized below.

Summary of Results (TBE) - Inter-laboratory Comparison Program (ICP)

The Teledyne Brown Engineering Environmental Services (TBE-ES) laboratory analyzed Performance Evaluation (PE) samples of air particulate (AP), milk, soil, vegetation, and water matrices that represent test and matrix combinations available for REMP programs. The PE samples supplied by E&Z Analytics Inc., Environmental Resource Associates (ERA), and Department of Energy (DOE) Mixed Analyte Performance Evaluation Program (MAPEP), were evaluated against the following pre-set acceptance criteria:

A. E&Z Analytics Evaluation Criteria Analytics evaluation report provides a ratio of TBEs result and E&Z Analytics known value.

Since flag values are not assigned by E&Z Analytics, TBE evaluates the reported ratios based on internal Quality Control (QC) requirements based on the DOE MAPEP criteria.

1. A = Acceptable - reported result falls within ratio limits of 0.80-1.20

2. W = Acceptable with warning - reported result falls within 0.70-0.80 or 1.20-1.30

3. N = Not Acceptable - reported result falls outside the ratio limits of < 0.70 and > 1.30 B. ERA Evaluation Criteria ERAs evaluation report provides an acceptance range for control and warning limits with associated flag values. ERAs acceptance limits are established per the US EPA, National Environmental Laboratory Accreditation Conference (NELAC), state-specific Performance Testing (PT) program requirements or ERAs SOP for the Generation of Performance Acceptance Limits, as applicable. The acceptance limits are either determined by a regression equation specific to each analyte or a fixed percentage limit promulgated under the appropriate regulatory document.

1. A = Acceptable - Reported value falls within the Acceptance Limits

2. N = Not Acceptable - Reported value falls outside of the Acceptance Limits

Annual Radiological Environmental Operating Report YEAR: 2024 Page 48 of 61 Company: Entergy Plant: Arkansas Nuclear One D. DOE Evaluation Criteria MAPEPs evaluation report provides an acceptance range with associated flag values.

MAPEP defines three levels of performance:

Acceptable (flag = A) - result within +/- 20% of the reference value Acceptable with Warning (flag = W) - result falls in the +/- 20% to +/- 30% of the reference value Not Acceptable (flag = N) - bias is greater than 30% of the reference value Note: The DOE MAPEP samples are created to mimic conditions found at DOE sites which do not always resemble typical environmental samples obtained at commercial nuclear power facilities.

The Inter-Laboratory Comparison Program provides evidence of in control counting systems and methods, and that the laboratories are producing accurate and reliable data. For the TBE laboratory, 152 out of 167 analyses performed met the specified acceptance criteria. Fifteen analyses did not meet the specified acceptance criteria and were addressed through the TBE Corrective Action Program. A summary is found below:

A. NCR 24-02: ERA March MRAD-40 study with Air Particulate AM-241 evaluated as "Not Acceptable." TBE reported 38.8 pCi/filter, and the known value returned at 55.0 pCi/filter (range 39.3-73.3). The root cause investigation determined that the sample was not logged into the system correctly and therefore not prepared with the required tracer. To correct and prevent recurrence, personnel involved are to utilize a template to ensure all analyses are logged as required and the QA Manager will perform sample log review as a back up to ensure accuracy. Acceptable results returned in a later sample study, supporting effectiveness of corrective action.

B. NCR 24-03: ERA March MRAD-40 air particulate study GR-B evaluated as "Not Acceptable." TBE reported 42.1 pCi/filter, and the known value returned at 22.2 pCi/filter (range 13.5-33.5). The root cause investigation determined that alpha-to-beta crosstalk was more significant than normal which caused the beta activity to report falsely high data. To correct and prevent recurrence, personnel involved are to adjust the alpha-to-beta crosstalk via correction calculation measures when high alpha activities are observed. Acceptable results returned in a later sample study, supporting effectiveness of corrective action.

C. NCR 24-05: ERA April RAD-137 water study GR-A evaluated as "Not Acceptable." TBE reported 35.2 pCi/L, and the known value returned at 52.6 pCi/L (range 39.6-65.6). The root cause investigation determined that the provided samples contained a solids content that was significantly higher than the typical client samples tested by the laboratory. A set aliquot volume for prior ERA samples was used and not adjusted to account for the sudden increase in solid content. To correct and prevent recurrence, new sample types were ordered from ERA that used Americium (Am)-231 to better reflect client sample testing and acceptable results were achieved. Acceptable results returned in a later sample study, supporting effectiveness of corrective action.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 49 of 61 Company: Entergy Plant: Arkansas Nuclear One D. NCR 24-06: E&Z Analytics March E14092 air particulate study Co-60 evaluated as "Not Acceptable." TBE reported 168 pCi and the known value returned at 126 pCi. Additionally, March E14093 soil Cerium (Ce)-141 evaluated as Not Acceptable. TBE reported 0.106 pCi/g, and the known value returned at 0.071 pCi/g. The root cause investigation was unable to determine any anomaly thus no proposed corrective action. No recurrence has occurred.

E. CAR 24-02 (CAR 23-31): MAPEP February 24-MaS50 soil study Fe-55 evaluated as "Not Acceptable." TBE reported 297 Becquerels / Kilogram (Bq/Kg), and the known value returned at 650 Bq/Kg (range 455-845). The root cause investigation suspects that the current analytical procedure is not sufficient to add the interferences added to the sample by MAPEP. This investigation is still ongoing (See NCR 24-16), as the suggested corrective action did not provide desired results.

F. NCR 24-08: MAPEP February 24-MaS50 soil study Ni-63 evaluated as "Not Acceptable."

TBE reported 1070 Bq/Kg, and the known value returned at 1530 Bq/Kg (range 1071-1989).

The root cause investigation suspected that the sample contained added interferences that are not typically seen in client samples. All QC efforts associated with the sample were acceptable and no anomalies found, even after reanalysis. To correct and prevent recurrence, samples suspected of additional interferences will include the addition of Ni-59 tracer to determine yield results when calculating results. TBE analytical procedure TBE-2013 was updated to include this change.

G. NCR 24-09: MAPEP February 24-MaSU50 urine study Zn-65 evaluated as Not Acceptable. The root cause investigation determined that the sample was spiked lower than TBEs typical detection limit and client requirements. The report was revised by MAPEP indicating Not Evaluated, resulting in this nuclide to not be considered a failure.

H. NCR 24-10: MAPEP February 24-MaW50 water study technetium (Tc)-99 evaluated as "Not Acceptable." TBE reported 9.95 Bq/L, and the known value returned 7.47 Bq/L (range 5.23-9.71). The root cause investigation suspects Thorium interference that was not removed during the column separation process of the analytical procedure; however, it cannot be confirmed as all QC efforts associated with the sample were acceptable and with no anomalies found. To potentially correct and prevent recurrence, an additional rinse step was added to the procedure. Acceptable results returned in a later sample study, supporting effectiveness of corrective action.

I.

NCR 24-11: MAPEP February 24-RdV50 vegetation study Strontium (Sr)-90 evaluated as "Not Acceptable." TBE reported 0.276 Bq/sample, and the known value returned 0.529 Bq/sample (range 0.370-0.688). The root cause investigation determined a laboratory accident resulting in a spilled (loss) of sample. No corrective action was performed as the cause was an unintentional sample spill.

J. NCR 24-14: ERA September MRAD-41 air particulate study Uranium (U)-234/238 evaluated as "Not Acceptable." TBE reported 14.0/14.2 pCi/filter, and the known value returned at 31.1/30.9 pCi/filter (range 23.1-36.9). The root cause investigation determined that the laboratory technician placed double the amount of tracer in the sample by error. To correct and prevent recurrence, samples that have been digested/leached with carrier/tracer added will have a label placed over the cap indicating it has already been added. Additionally, the beaker that aliquot is put in should have markings to indicate carrier/tracer has already been added to the sample.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 50 of 61 Company: Entergy Plant: Arkansas Nuclear One K. NCR 24-15: ERA September MRAD-41 water study Fe-55 evaluated as "Not Acceptable."

TBE reported 615 pCi/L, and the known value returned at 1230 pCi/L (range 723-1790).

The root cause is still under investigation.

L. NCR 24-16: MAPEP August 24-MaS50 soil study Fe-55 evaluated as "Not Acceptable."

TBE did not report a value, and the known value returned 780 Bq/Kg (range 546-1014). The root cause is still under investigation.

M. NCR 24-17: MAPEP August 24-RdV51 vegetation study Sr-90 evaluated as "Not Acceptable." TBE reported 0.95 Bq/sample, and the known value returned 2.39 Bq/sample (range 1.67-3.11). The root cause is still under investigation.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 51 of 61 Company: Entergy Plant: Arkansas Nuclear One ENVIRONMENTAL DOSIMETRY COMPANY ANNUAL QUALITY ASSURANCE STATUS REPORT January - December 2024 Prepared By:

Date:

Approved By:

Date:

Environmental Dosimetry Company 10 Ashton Lane Sterling, MA 01564

Annual Radiological Environmental Operating Report YEAR: 2024 Page 52 of 61 Company: Entergy Plant: Arkansas Nuclear One TABLE OF CONTENTS Page EXECUTIVE

SUMMARY

........................................................................................................................ 53 I.

INTRODUCTION............................................................................................................. 53 A.

QC Program.................................................................................................... 53 B.

QA Program.................................................................................................... 53 II.

PERFORMANCE EVALUATION CRITERIA................................................................... 54 A.

Acceptance Criteria for Internal Evaluations................................................... 54 B.

QC Investigation Criteria and Result Reporting.............................................. 55 C.

Reporting of Environmental Dosimetry Results to EDC Customers............... 56 III.

DATA

SUMMARY

FOR ISSUANCE PERIOD JANUARY-DECEMBER 2024................ 56 A.

General Discussion......................................................................................... 56 B.

Result Trending.............................................................................................. 56 IV.

STATUS OF EDC CONDITION REPORTS (CR)........................................................... 57 V.

STATUS OF AUDITS/ASSESSMENTS.......................................................................... 57 VI.

PROCEDURES AND MANUALS REVISED DURING JANUARY -

DECEMBER 2024........................................................................................................... 57 VII.

CONCLUSION AND RECOMMENDATIONS................................................................. 57 VIII.

REFERENCES................................................................................................................ 57 APPENDIX A DOSIMETRY QUALITY CONTROL TRENDING GRAPHS............................................. 59 TABLES Table 1 PERCENTAGE OF INDIVIDUAL DOSIMETERS THAT PASSED EDC INTERNAL CRITERIA JANUARY - DECEMBER 2024(1), (2)....................................................................................................... 57 Table 2 MEAN DOSIMETER ANALYSES (N=6) JANUARY - DECEMBER 2024(1), (2)......................... 58 Table 3

SUMMARY

OF INDEPENDENT DOSIMETER TESTING JANUARY - DECEMBER 2024(1), (2)

................................................................................................................................................................ 58

Annual Radiological Environmental Operating Report YEAR: 2024 Page 53 of 61 Company: Entergy Plant: Arkansas Nuclear One EXECUTIVE

SUMMARY

Routine quality control (QC) testing was performed for dosimeters issued by the Environmental Dosimetry Company (EDC).

During this annual period100% (72/72) of the individual dosimeters, evaluated against the EDC internal performance acceptance criteria (high-energy photons only), met the criterion for accuracy and 100% (72/72) met the criterion for precision (Table 1). In addition, 100% (12/12) of the dosimeter sets evaluated against the internal tolerance limits met EDC acceptance criteria (Table 2) and 100% of independent testing passed the performance criteria (Table 3).

Trending graphs, which evaluate performance statistic for high-energy photon irradiations and co-located stations are given in Appendix A.

One internal assessment was performed in 2024. There were no findings.

I.

INTRODUCTION The TLD systems at the Environmental Dosimetry Company (EDC) are calibrated and operated to ensure consistent and accurate evaluation of TLDs. The quality of the dosimetric results reported to EDC clients is ensured by in-house performance testing and independent performance testing by EDC clients, and both internal and client directed program assessments.

The purpose of the dosimetry quality assurance program is to provide performance documentation of the routine processing of EDC dosimeters. Performance testing provides a statistical measure of the bias and precision of dosimetry processing against a reliable standard, which in turn points out any trends or performance changes. Two programs are used:

A.

QC Program Dosimetry quality control tests are performed on EDC Panasonic 814 Environmental dosimeters. These tests include: (1) the in-house testing program coordinated by the EDC QA Officer and (2) independent test perform by EDC clients. In-house tests are performed using six pairs of 814 dosimeters, a pair is reported as an individual result and six pairs are reported as the mean result. Results of these tests are described in this report.

Excluded from this report are instrumentation checks. Although instrumentation checks represent an important aspect of the quality assurance program, they are not included as process checks in this report. Instrumentation checks represent between 5-10% of the TLDs processed.

B.

QA Program An internal assessment of dosimetry activities is conducted annually by the Quality Assurance Officer (Reference 1). The purpose of the assessment is to review procedures, results, materials or components to identify opportunities to improve or enhance processes and/or services.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 54 of 61 Company: Entergy Plant: Arkansas Nuclear One II.

PERFORMANCE EVALUATION CRITERIA A.

Acceptance Criteria for Internal Evaluations

1.

Bias For each dosimeter tested, the measure of bias is the percent deviation of the reported result relative to the delivered exposure. The percent deviation relative to the delivered exposure is calculated as follows:

i i

i H

H 100 H

where:

iH =

the corresponding reported exposure for the ith dosimeter (i.e., the reported exposure)

Hi = the exposure delivered to the ith irradiated dosimeter (i.e.,

the delivered exposure)

2.

Mean Bias For each group of test dosimeters, the mean bias is the average percent deviation of the reported result relative to the delivered exposure. The mean percent deviation relative to the delivered exposure is calculated as follows:

i i

i H

H 1

100 H

n where:

iH =

the corresponding reported exposure for the ith dosimeter (i.e., the reported exposure) iH =

the exposure delivered to the ith irradiated test dosimeter (i.e., the delivered exposure) n =

the number of dosimeters in the test group

Annual Radiological Environmental Operating Report YEAR: 2024 Page 55 of 61 Company: Entergy Plant: Arkansas Nuclear One Precision For a group of test dosimeters irradiated to a given exposure, the measure of precision is the percent deviation of individual results relative to the mean reported exposure. At least two values are required for the determination of precision. The measure of precision for the ith dosimeter is:

i H

H 100 H

where:

iH = the reported exposure for the ith dosimeter (i.e., the reported exposure)

H= the mean reported exposure, i.e.,

i 1

H H

n n = the number of dosimeters in the test group

3.

EDC Internal Tolerance Limits All evaluation criteria are taken from the EDC Quality System Manual, (Reference 2). These criteria are only applied to individual test dosimeters irradiated with high-energy photons (Cs-137) and are as follows for Panasonic Environmental dosimeters: +/- 15% for bias and +/- 12.8% for precision.

B.

QC Investigation Criteria and Result Reporting EDC Quality System Manual (Reference 2) specifies when an investigation is required due to a QC analysis that has failed the EDC bias criteria. The criteria are as follows:

1.

No investigation is necessary when an individual QC result falls outside the QC performance criteria for accuracy.

2.

Investigations are initiated when the mean of a QC processing batch is outside the performance criterion for bias.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 56 of 61 Company: Entergy Plant: Arkansas Nuclear One C.

Reporting of Environmental Dosimetry Results to EDC Customers

1.

All results are to be reported in a timely fashion.

2.

If the QA Officer determines that an investigation is required for a process, the results shall be issued as normal unless if the QC results prompting the investigation have a mean bias from the known of greater than +/-20%, then the results shall be issued with a note indicating that they may be updated in the future, pending resolution of a QA issue.

3.

Environmental dosimetry results do not require updating if the investigation has shown that the mean bias between the original results and the corrected results, based on applicable correction factors from the investigation, does not exceed

+/-15%.

III.

DATA

SUMMARY

FOR ISSUANCE PERIOD JANUARY-DECEMBER 2024 A.

General Discussion Results of performance tests conducted are summarized and discussed in the following sections. Summaries of the performance tests for the reporting period are given in Tables 1 through 3 and Figures 1 through 4.

Table 1 provides a summary of individual dosimeter results evaluated against the EDC internal acceptance criteria for high-energy photons only. During this period100%

(72/72) of the individual dosimeters, evaluated against these criteria, met the tolerance limits for accuracy and 100% (72/72) met the criterion for precision. A graphical interpretation is provided in Figures 1 and 2.

Table 2 provides the bias and standard deviation results for each group (N=6) of dosimeters evaluated against the internal tolerance criteria. Overall,100% (12/12) of the dosimeter sets, evaluated against the internal tolerance performance criteria, met these criteria. A graphical interpretation is provided in Figure 3.

Table 3 presents the independent blind spike results for dosimeters processed during this annual period. All results passed the performance acceptance criterion. Figure 4 is a graphical interpretation of Seabrook Station blind co-located station results.

B.

Result Trending One of the main benefits of performing quality control tests on a routine basis is to identify trends or performance changes. The results of the Panasonic environmental dosimeter performance tests are presented in Appendix A. The results are evaluated against each of the performance criteria listed in Section II, namely: individual dosimeter accuracy, individual dosimeter precision, and mean bias.

All the results presented in Appendix A are plotted sequentially by processing date.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 57 of 61 Company: Entergy Plant: Arkansas Nuclear One IV.

STATUS OF EDC CONDITION REPORTS (CR)

No condition reports were issued during this annual period.

V.

STATUS OF AUDITS/ASSESSMENTS

1.

Internal EDC Internal Quality Assurance Assessment was conducted during the fourth quarter 2024. There were no findings identified.

2.

External None.

VI.

PROCEDURES AND MANUALS REVISED DURING JANUARY - DECEMBER 2024 No procedures or manuals were revised in 2024.

VII.

CONCLUSION AND RECOMMENDATIONS The quality control evaluations continue to indicate the dosimetry processing programs at the EDC satisfy the criteria specified in the Quality System Manual. The EDC demonstrated the ability to meet all applicable acceptance criteria.

VIII.

REFERENCES

1.

EDC Quality Control and Audit Assessment Schedule, 2024.

2.

EDC Manual 1, Quality System Manual, Rev. 4, September 28, 2020.

Table 1 PERCENTAGE OF INDIVIDUAL DOSIMETERS THAT PASSED EDC INTERNAL CRITERIA JANUARY - DECEMBER 2024(1), (2)

Dosimeter Type Number Tested

% Passed Bias Criteria

% Passed Precision Criteria Panasonic Environmental 72 100 100 (1)This table summarizes results of tests conducted by EDC.

(2)Environmental dosimeter results are free in air.

Annual Radiological Environmental Operating Report YEAR: 2024 Page 58 of 61 Company: Entergy Plant: Arkansas Nuclear One Table 2 MEAN DOSIMETER ANALYSES (N=6) JANUARY - DECEMBER 2024(1), (2)

Process Date Exposure Level Mean Bias %

Standard Deviation %

Tolerance Limit +/-15%

5/05/2024 37

-0.3 2.2 Pass 5/08/2024 51 2.2 1.5 Pass 5/15/2024 83 2.5 2.2 Pass 7/30/2024 27 1.1 1.8 Pass 8/06/2024 63 6.6 1.2 Pass 9/25/2024 95

-3.1 1.8 Pass 10/24/2024 42 4.9 2.6 Pass 10/30/2024 73 6.8 1.6 Pass 11/27/2024 107

-6.7 1.6 Pass 01/20/2025 32 1.9 1.0 Pass 01/26/2025 47 2.8 1.5 Pass 01/29/2025 117 2.6 2.1 Pass (1)This table summarizes results of tests conducted by EDC for TLDs issued in 2024.

(2)Environmental dosimeter results are free in air.

Table 3

SUMMARY

OF INDEPENDENT DOSIMETER TESTING JANUARY - DECEMBER 2024(1), (2)

Issuance Period Client Mean Bias %

Standard Deviation %

Pass / Fail 1st Qtr. 2024 Millstone

-0.1 0.2 Pass 2nd Qtr.2024 Seabrook 1.7 2.8 Pass 2nd Qtr. 2024 Millstone

-4.3 0.9 Pass 3rd Qtr. 2024 SONGS

-9.7 1.4 Pass 3rd Qtr. 2024 Millstone

-1.4 2.5 Pass 4th Qtr.2024 Millstone 1.5 1.4 Pass 4th Qtr.2024 Seabrook 3.8 1.5 Pass (1)Performance criteria are +/- 15%.

(2)Blind spike irradiations using Cs-137

Annual Radiological Environmental Operating Report YEAR: 2024 Page 59 of 61 Company: Entergy Plant: Arkansas Nuclear One APPENDIX A DOSIMETRY QUALITY CONTROL TRENDING GRAPHS ISSUE PERIOD JANUARY - DECEMBER

Annual Radiological Environmental Operating Report YEAR: 2024 Page 60 of 61 Company: Entergy Plant: Arkansas Nuclear One

Annual Radiological Environmental Operating Report YEAR: 2024 Page 61 of 61 Company: Entergy Plant: Arkansas Nuclear One

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