ML25134A037

Annual Radiological Environmental Operating Report January 1, 2024 Through December 31, 2024

ML25134A037
Person / Time
Site:	Duane Arnold
Issue date:	05/08/2025
From:	Microbac Labs, NextEra Energy Duane Arnold
To:	NRC/RGN-III
References
NG-25-0007
Download: ML25134A037 (1)

Text

©) MICROBAc*

700 Landwehr Road* Northbrook, ll 60062-2310 phone (847) 564-0700

• fax (847) S64-.4517 DUANE ARNOLD ENERGY CENTER CEDAR RAPIDS, IOWA DOCKET NO. 50-331 REPORT to the UNITED STATES NUCLEAR REGULATORY COMMISSION Annual Radiological Environmental Operating Report January 1 to December 31, 2024 Prepared by Microbac Laboratories - Northbrook Project No. 8001 Approved : -~-~

J_._

Ashok Banavali, Ph.D.

Laboratory Director

PREFACE Staff members of the Microbac Laboratories - Northbrook were responsible for the acquisition of data presented in this report, with the exception of Appendices D and E which were completed by DAEC personnel. All environmental samples, with the exception of aquatic, were collected by personnel of DAEC. Aquatic samples were collected by the University of Iowa Hygienic Laboratory.

The report was prepared by Microbac Laboratories - Northbrook, with the exception of Appendices D and E, which were prepared by DAEC personnel.

ii

TABLE OF CONTENTS PARTI PREFACE..................................................................................................................... ii List of Tables.................................................................................................................... v List of Figures................................................................................................................. vi

1.0 INTRODUCTION

........................................................................................................... 1 2.0

SUMMARY

.................................................................................................................... 2 3.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM................................ 3 3.1 Program Design and Data Interpretation........................................................... 3 3.2 Program Description............................................................................................. 4 3.2.1 Environmental Monitoring......................................................................... 4 3.2.2 Groundwater Protection Program............................................................. 4 3.3 Program Execution............................................................................................... 5 3.4 Laboratory Procedures....................................................................................... 5 3.5 Program Modifications.......................................................................................... 5 4.0 RES UL TS AND DISCUSSION........................................................................................ 6 4.1 Atmospheric Nuclear Detonations and Nuclear Accidents..................................... 6 4.2 Program Findings................................................................................................. 6 4.3 Groundwater Protection Program Findings......................................................... 8 5.0 TABLES AND FIGURES................................................................................................. 9

6.0 REFERENCES

CITED................................................................................................ 24 APPENDICES A

lnterlaboratory Comparison Program Results...................................................... A-1 B

Data Reporting Conventions................................................................................ B-1 C

Effluent Concentration Limits for Radioactivity in Air and Water Above Background in Unrestricted Areas........................................................................ C-1 D

Summary of the Land Use Census...................................................................... D-1 E

Annual Radiation Dose Assessment.................................................................... E-1 iii

TABLE OF CONTENTS (continued)

PARTII Data Tabulations and Analyses....................................................................................... i iv

LIST OF TABLES 5.1 Characteristic Properties of Isotopes Quantified in Gamma-spectroscopic Analyses......................................................................................................................... 10 5.2 Sample Collection and Analysis Program...................................................................... 11 5.3 Sampling Locations, DAEC.......................................................................................... 13 5.4 Type and Frequency of Collections................................................................................ 15 5.5 Sample Codes for Tables 5.4 and 5.6.......................................................................... 16 5.6 Program Deviations.......................................................................................................... 17 5.7 Radiological Environmental Monitoring Program Summary.................................. 18 In addition, the following tables are included in the Appendices:

Appendix A A-0 Attachment A.................................................................................................................. A-2 A-1 Environmental Resource Associates (RAD).................................................................. A-3 A-2 lnterlaboratory Comparison Program Results, Thermoluminescent Dosimeters(TLDs ).......................................................................... A-4 A-3 In-house "Spiked" Samples............................................................................................ A-6 A-4 In-house "Blank" Samples............................................................................................ A-9 A-5 In-house "Duplicate" Samples.................................................................................... A-11 A-6 Department of Energy MAPEP comparison results.................................................... A-15 A-7 Environmental Resource Associates (MRAD).................................................... A-17 AppendixC C-1 Effluent Concentration Limits for Radioactivity in Air and Water Above Background in Unrestricted Areas.............................................................. C-2 V

LIST OF FIGURES 5.1 Environmental Monitoring Programs Sampling near the Duane Arnold Energy Center small area......................................................... 22 5.2 Radiological Environmental Monitoring Program Sampling Stations Outside 0.5 Miles from DAEC Large Area.................................................................... 23 vi

1.0 INTRODUCTION

This report summarizes and interprets results of the Radiological Environmental Monitoring Program (REMP) conducted by Environmental, Inc., Midwest Laboratory at the Duane Arnold Energy Center, Palo, Iowa, during the period January - December 2024. This Program monitors the levels of radioactivity in the air, terrestrial, and aquatic environments in order to assess the impact of the plant on its surroundings.

The REMP fulfills the requirements of Sections IV.B.2 and IV.B.3 of Appendix I to 10 CFR 50 for the operation of the plant. The REMP also fulfills the requirements of 10 CFR 72.44(d)(2) for operation of the ISFSI.

Tabulations of individual analyses made during the year are included in Part 11 of this report.

The Duane Arnold Energy Center (DAEC) is a boiling water reactor, located in Linn County, Iowa, on the Cedar River, and owned and operated by NextEra Energy Resources. Initial criticality was attained on March 23, 197 4. The reactor reached 100% power on August 12, 197 4. Commercial operation began on February 1, 1975.

The DAEC permanently shut down on August 10, 2020. NextEra Energy Duane Arnold (NEDA) informed the NRC by letter dated August 27, 2020 (Accession No. ML20240A067); certifying the permanent cessation of power operations at the DAEC.

In October 2020 NEDA certified by letter (ML20286A317) the permanent defueling of the reactor at DAEC. Therefore, as specified in 10 CFR 50.82(a)(2), the 10 CFR Part 50 license for DAEC no longer authorizes operations of the reactor or emplacement or retention of fuel into the reactor vessel.

In April 2022 all the nuclear fuel had been removed from the fuel pool and placed in dry cask storage at the site Independent Spent Fuel Storage Installation (ISFSI). There are no effluents from the ISFSI based on the design of the casks.

By December 2022 the plant was in SAFSTOR (a long-term storage condition for a permanently shutdown nuclear power plant). During SAFSTOR, radioactive contamination decreases substantially, making subsequent decontamination and demolition easier and reducing the amount of low level radioactive waste requiring disposal. All radioactive and service water systems were drained or placed in a stable condition. Plant systems are monitored, and adverse conditions are documented and addressed as needed.

The contribution of dose to a member of the public is most likely to be exposed from liquid and gaseous effluent releases. Calculation methods in the Defueled Offsite Dose Assessment Manual (DODAM) follow those prescribed by Regulatory Guide 1.109, "Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I".

2.0

SUMMARY

The Radiological Environmental Monitoring Program, as required by the U.S. Nuclear Regulatory Commission (NRC) Technical Specifications for the Duane Arnold Energy Center, is herein described.

Results for the year 2024 are summarized and discussed. Information regarding DAEC effluents and the Defueled Offsite Dose Assessment Manual (DODAM) can be found in the 2024 DAEC Annual Radiological Material Release Report (ARMRR).

Program findings show only background levels of radioactivity in the environmental samples collected in the vicinity of the Duane Arnold Energy Center.

No effect on the environment is indicated in the areas surrounding the site of the Duane Arnold Energy Center.

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3.1 3.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM Program Design and Data Interpretation The purpose of the Radiological Environmental Monitoring Program at the Duane Arnold Energy Center (DAEC) is to assess the impact of the plant on its environment. For this purpose, samples are collected from the air, terrestrial, and aquatic environments and analyzed for radioactive content. In addition, ambient gamma radiation levels are monitored by thermoluminescent dosimeters (TLDs).

Sources of environmental radiation include the following:

(1)

Natural background radiation arising from cosmic rays and primordial radionuclides; (2)

Fallout from atmospheric nuclear detonations; (3)

Releases from nuclear power plants; and (4)

Industrial and medical radioactive waste.

In interpreting the data, effects due to the DAEC operation must be distinguished from those due to other sources.

A major interpretive aid in assessment of these effects is the design of the monitoring program at the DAEC which is based on the indicator-control concept. Most types of samples are collected both at indicator locations (nearby, downwind, or downstream) and at control locations (distant, upwind, or upstream). A station effect would be indicated if the radiation level at an indicator location was significantly larger than that at the control location. The difference would have to be greater than could be accounted for by typical fluctuations in radiation levels arising from other sources.

An additional interpretive technique involves analyses for specific radionuclides present in the environmental samples collected from the DAEC site. The DAEC's monitoring program includes analyses for strontium-90 which are fission products, and tritium, which is produced by cosmic rays, atmospheric nuclear detonations, and also by nuclear power plants. Most samples are also analyzed for gamma-emitting isotopes with results for the following groups quantified: zirconium-95, cesium-137, and cerium-144. These three gamma-emitting isotopes were selected as radiological impact indicators because of the different characteristic proportions in which they appear in the fission product mix produced by a nuclear reactor and that produced by a nuclear detonation. Each of the three isotopes is produced in roughly equivalent amounts by a reactor:

each constitutes about 10% of the total activity of fission products ten (10) days after reactor shutdown. Alternatively, ten (10) days after a nuclear explosion, the contributions of zirconium-95, cerium-144, and cesium-137 to the activity of the resulting debris are in the approximate ratio 4: 1 :0.03 (Eisenbud, 1963). The other group quantified consists of niobium-95, ruthenium-103 and -

106, cesium-134, barium-lanthanum-140, and cerium-141. These isotopes are released in small quantities by nuclear power plants, but to date their major source of injection into the general environment has been atmospheric nuclear testing. Nuclides of the next group, manganese-54, cobalt-58 and-60, and zinc-65, are activation products and arise from activation of corrosion products. They are typical components of nuclear power plant effluents, but are not produced in significant quantities by nuclear detonations. Nuclides of the final group, beryllium-?, which is of cosmogenic origin, and potassium-40, a naturally-occurring isotope, were chosen as calibration monitors and provide a comparison between levels of naturally occurring radionuclides and radionuclides that could be attributed to the operation of the plant.

Characteristic properties of isotopes quantified in gamma-spectroscopic analysis are presented in Table 5.1. Other means of distinguishing sources of environmental radiation can be employed in interpreting the data. Current radiation levels can be compared with previous levels, including those measured before the plant became operational. Results of the DAEC's Monitoring Program 3

can be related to those obtained in other parts of the world. Finally, results can be related to events known to cause elevated levels of radiation in the environment, e.g., atmospheric nuclear detonations.

3.2 Program Description 3.2.1 Environmental Monitoring The sampling and analysis schedule for the Radiological Environmental Monitoring Program (REMP) at the DAEC is summarized in Table 5.2 and is briefly reviewed below. Table 5.3 defines the sampling location codes used in Table 5.2 and specifies for each location its distance, direction, and sector relative to the reactor site. The types of samples collected at each location and the frequency of collections are presented in Table 5.4 using codes defined in Table 5.5.

To monitor the air environment, a continuous air sampler is employed. Airborne particulates at the remaining locations are indicators: D-15 and D-16. Filters are changed and counted bi-weekly. Particulate filters are analyzed for gross beta activity. If gross beta activity exceeds ten times the yearly mean of the control samples, gamma isotopic analysis is performed. Quarterly composites of airborne particulates from each location are analyzed for gamma emitting isotopes.

Ambient gamma radiation is monitored at a total of 22 locations. A TLD is placed at each location and exchanged and analyzed quarterly.

Surface water is collected monthly from two total locations: D-49 and D-61. The monthly samples are analyzed for tritium and gamma-emitting isotopes.

The aquatic environment is also monitored at 0-49 and 0-61 with semiannual fish collection.

Cedar River bottom sediment is collected semiannually at the 0-49 and 0-51. The samples are analyzed for gamma-emitting isotopes.

Drinking water is collected monthly from D-52 and D-53. The samples are analyzed for tritium and gamma emitting isotopes. Any positive identification of a reactor by-product material initiates analyses for hard to detect isotopes of Ni-63, Sr-89, Sr-90, Fe-55 and gross alpha.

Milk sampling was discontinued in November of 2020.

Additional monitoring of the terrestrial environment, grain, forage and broad leaf vegetation samples are collected annually, as available, from two indicators locations D-015 and 0-016.

Grain, forage and broad leaf (green leafy) vegetation samples are analyzed for gamma-emitting isotopes and at least two broad leaf vegetation samples are analyzed for iodine-131.

If any of the cattle grazing on-site are slaughtered for home use, a meat sample is collected. The sample is analyzed for gamma-emitting isotopes.

3.2.2 Groundwater Protection Program 3.3 The Duane Arnold Energy Center has committed to the Nuclear Energy lnstitute's Industry Groundwater Protection Initiative - NEI 07-07. The sampling and collection schedule can be found in DODAM Table 6.3-2, and the sampling locations are shown in Figure 5-1 and Figure 5-2.

Program Execution The program was executed as described in the preceding section without exception.

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3.4 Laboratory Procedures Levels of iodine-131 in vegetation and concentrations of airborne iodine-131 were determined by gamma spectroscopy.

Gamma-spectroscopic analyses are performed using high-purity germanium (HPGe) detectors.

The gamma isotopic analysis provides a spectrum with an energy range from 80 to 2048 KeV.

Specific isotopes included in the gamma library are Mn-54, Fe-59, Co-58, Co-60, Zn-65, Zr-95, Nb-95, Ru-103, Ru-106, 1-131, Ba-La-140, Cs-134, Cs-137, Ce-141, and Ce-144. Naturally occurring gamma-emitters, such as Be-7, K-40 and Ra daughters, are frequently detected but may not be listed.

Tritium was measured by liquid scintillation spectrometry.

Analytical Procedures used by Environmental, Inc. are on file and are available for inspection.

Procedures are based on those prescribed by the Health and Safety Laboratory of the U.S. Dep't of Energy, Edition 28, 1997, U.S. Environmental Protection Agency for Measurement of Radioactivity in Drinking Water, 1980, and the U.S. Environmental Protection Agency, EERF, Radiochemical Procedures Manual, 1984.

Microbac Laboratories - Northbrook (previously Environmental Inc. Midwest laboratory) has a comprehensive quality control/quality assurance program designed to assure the reliability of data obtained. Details of the QA Program are presented elsewhere (Microbac Laboratories Inc -

Northbrook, 2024 ). The QA Program includes participation in lnterlaboratory Comparison (crosscheck) Programs. Results obtained in crosscheck programs are presented in Appendix A.

3.5 Program Modifications No changes for 2024.

5

4.1 4.2 4.0 RESULTS AND DISCUSSION All collections and analyses were made as scheduled, except for those listed in Table 5.6.

Results are summarized in Table 5.7 as recommended by the Nuclear Regulatory Commission.

For each type of analysis and sample medium, the table lists the mean and range of all indicator and control locations, as well as that location with the highest mean and range.

Tabulated results of measurements are not included in this section, although reference to these results will be made in discussion. A complete tabulation of results for 2024 is contained in Part II of the Annual Report on the Radiological Environmental Monitoring Program for the Duane Arnold Energy Center.

Atmospheric Nuclear Detonations and Nuclear Accidents There were no reported accidents involving significant release to the environment at nuclear reactor facilities in 2024. The Fukushima Daiichi nuclear accident occurred March 11, 2011.

There were no reported atmospheric nuclear tests in 2024. The last reported test was conducted on October 16, 1980 by the People's Republic of China.

Program Findings Results obtained show background levels of radioactivity in the environmental samples collected outside of the Owner Controlled Area in 2024.

Airborne Particulates The average annual gross beta concentrations in airborne particulates were 0.024 pCi/m3 at the indicator locations. Sampling has been discontinued at the control location. The results are consistent with levels observed from 2000 through 2023. The historical results are tabulated below.

Year Indicators Controls Year Indicators Controls Concentration (pCi/m3)

Concentration (pCi/m3) 2000 0.026 0.027 2013 0.028 0.025 2001 0.026 0.026 2014 0.026 0.025 2002 0.027 0.027 2015 0.027 0.024 2003 0.029 0.029 2016 0.027 0.023 2004 0.028 0.028 2017 0.028 0.025 2005 0.031 0.031 2018 0.028 0.026 2006 0.029 0.027 2019 0.026 0.025 2007 0.031 0.031 2020 0.026 0.026 2008 0.029 0.029 2021 0.031 0.028 2009 0.031 0.030 2022 0.030 0.053 2010 0.028 0.028 2023 0.030 NA 2011 0.030 0.029 2024 0.024 NA 2012 0.030 0.029 Average annual gross beta concentrations in airborne particulates.

NA-Not analyzed. Sampling has been discontinued at the control location.

6

4.2 Program Findings, Airborne Particulates (continued)

Gamma spectroscopic analysis of quarterly composites of air particulate filters yielded Beryllium-?

results for the indicator locations similar to last year's results. Sampling has been discontinued at the control location. Beryllium-7,produced continuously in the upper atmosphere by cosmic radiation (Arnold and AI-Salih, 1955), is typically detected in quarterly air samples. No reactor by-product radionuclides were identified in any of the air samples analyzed. All samples met required lower limits of detection as specified in the DODAM.

Airborne Iodine All iodine sampling has been discontinued.

Ambient Radiation (TLDs)

At the control location, D-4, thermoluminescent dosimeter (TLD) readings averaged 15.7 mR/quarter. At locations within a half mile, one mile and three mile radius of the stack, the measurements averaged 16.4, 16.6 and 15.5 mR/quarter, respectively. The on-site location D-15 averaged 14.2 mR/quarter. These average measurements are similar to the estimated average natural background radiation for Middle America, 19.5 mR/quarter, which is based on data on Pages 71 and 108 of the report, "Natural Background Radiation in the United States" (National Council on Radiation Protection and Measurements, 1975). The terrestrial absorbed dose (uncorrected for structural and body shielding) ranges from 8.8 to 18.8 mrad/quarter and averages 11.5 mrad/quarter for Middle America. Cosmic radiation and cosmogenic radionuclides contribute 8.0 mrad/quarter for a total average of 19.5 mrad/quarter. No plant effect is indicated.

ISFSI Facility Operations Monitoring Four TLDs, placed directionally along the ISFSI fence line, averaged 57.0 mR/quarter.

Groundwater (drinking water-potable) 24 drinking water samples from two locations were collected in 2024. Tritium concentrations in ground water samples were less than the MDC of 188 pCi/L in all samples analyzed. 1-131 and other gamma-emitting isotopes were below detection limits.

No reactor by-product radionuclides could be identified. All samples met required lower limits of detection as specified in the DODAM.

7

4.2 Program Findings (continued)

Vegetation Six vegetation samples from two locations were collected in 2024 consisting of green leafy vegetation, forage and grain samples. lodine-131 concentrations in all vegetation samples were less than the LLD level of 0.018 pCi/g wet weight in the two green leafy vegetation samples and less 0.022 pCi/g wet in the four grain and forage samples analyzed.

Naturally occurring potassium-40 was the only other gamma-emitting isotope observed in all vegetation samples, all other gamma-emitting isotopes were below detection limits. All samples met required lower limits of detection as specified in the DODAM.

Surface Water 24 surface water samples were collected from two locations in 2024. No tritium was detected above an LLD of 188 pCi/L. No gamma emitting isotopes were measured above their respective LLD's in any of the samples tested.

Fish Eight fish samples from five sport fish species were collected in April and October, 2024, and analyzed for gamma-emitting isotopes. With the exception of naturally-occurring potassium-40, no gamma-emitting isotopes were identified in edible portions of the fish. The average potassium-40 level was similar at both the indicator and control locations (3.67 and 3.81 pCi/g wet, respectively).

No reactor by-product radionuclides were identified. All samples met required lower limits of detection as specified in the DODAM.

River Sediments Four river sediment samples from two locations were collected in 2024 during the months of April and October and analyzed for gamma-emitting isotopes. Potassium-40 activity ranged from 9.38 to 11.30 pCi/g dry weight at the indicator locations and between 8.32 and 8.91 pCi/g dry weight at the control location.

All samples met required lower limits of detection as specified in the DODAM.

4.3 Groundwater 33 groundwater samples (non-potable water) were collected from 33 monitoring wells in 2024. Tritium was the only plant by-product identified. Concentrations of tritium ranged from less than 174 pCi/L to 386 pCi/L at D-67, monitoring well MW-22A Tritium was not identified in any drinking water well on-site or at off-site wells or Cedar Rapids municipal drinking water samples. Lastly, at the monitoring well farthest down gradient prior to the boundary of the owner-controlled area and the Cedar River, MW-33A, no tritium was detected above an MDC of 174 pCi/L.

8

5.0 TABLES AND FIGURES 9

Table 5.1 Characteristic properties of isotopes quantified in gamma-spectroscopic analyses.

Designation Comment Isotope Half-life a Naturally Occurring A. Cosmogenic Produced by interaction of cosmic rays Be-7 53.2 d with atmosphere

8. Terrestrial Primordial K-40 1.26 X 109 y II. Fission Products b Nuclear accidents and detonations constitute the major environmental source.

A. Short-lived 1-131 8.04 d Ba-140 12.8 d B. Other than Short-lived Nb-95 35.15 d Zr-95 65 d Ru-103 39.35 d Ru-106 368.2 d Cs-134 2.061 y Cs-137 30.174 y Ce-141 32.5 d Ce-144 284.31 d Ill. Activation Products Typically found in nuclear power plant Mn-54 312.5 d effluents Fe-59 45.0 d Co-58 70.78 d Co-60 5.26 y Zn-65 245 d Half-lives are taken from Appendix E of Environmental Quarterly, 1 JanuarY 1978, EML-334 (U. S. Department of Energy, 1978).

Includes fission-product daughters.

Table 5.2 Sample collection and analysis program.

Sampling Location a Exposure Sample Description Sampling and Collection Type and Frequency Pathway and/or Point Frequency of Analysis b Sample Type Airborne 15 On-site North Continuous operation of Analyze for gross beta activity Particulates 16 On-site South sampler with sample more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after filter collection at least once change. Perform gamma isotopic monthly or as required analysis on each sample having by dust loading gross beta activity greater than ten times the yearly mean of the control samples.

Composite weekly samples to form a quarterly composite (by location).

Analyze quarterly composite for gamma isotopic.

Ambient 4

(Controls)

One dosimeter continuously Read gamma radiation dose Radiation at each location.

quarterly.

(Indicators) 15,17,18, Within 0.5 mile of Dosimeters are changed at 20,22,29, Stack least quarterly.

31, 83, 85 Within 3.0 miles of 33,35,37, Stack 39,42 Within 1.0 mile of 43,46,48 Stack 161-164 ISFSI Fence line Surface Water 49 Lewis Access (C)

Once per month.

Gamma isotopic and tritium 61 Plant Discharge analysis for each sample (by

- 1/2 mi. downstream location).

from Plant Discharge 11

Table 5.2 Sample collection and analysis program, (continued).

Sampling Location a Exposure Sample Description Sampling and Collection Type and Frequency Pathway and/or Point Frequency of Analysis b Sample Type 52 Plant potable water Ground Water 53 Treated Municipal Grab sample at least Analysis gamma emitting isotopes, Water once per quarter and tritium on quarterly samples.

If reactor by-product gamma emitters are identified, or if tritium concentrations measure > MDA, then analyze for Ni-63, Sr-89, Sr-90 and alpha emitters.

River 49 Lewis Access At least once every six Gamma isotopic analysis of each Sediment months.

sample 51 Plant Discharge Vegetation 15,16 Farms raising food Annually at harvest Gamma isotopic analysis, of crops time. Two samples of each sample.

each: grain, green leafy, and forage.

Fish 49 Cedar River upstream One sample per 6 Gamma isotopic analysis on edible of DAEC not months (once during portions.

influenced by effluent January through June (C) and once during July through December).

61 Downstream of DAEC in influence of effluent

• (C) denotes control location. All other locations are indicators.

b Gamma isotopic analysis and analysis for gamma-emitting nuclides refer to high resolution gamma ray spectrum analysis.

c Sample collection discontinued after 01-08-22 collection period 12

Table 5.3 Sampling locations, Duane Arnold Energy Center.

Sampling Location Code Location Description Distance and Direction from Site Stack D-4 Pleasant Creek SRA 4,960 meters NW D-15 On-site, North-Northwest 1,050 meters NNW D-17 On-site, N 1,050 meters N D-18 On-site, NNE 630 meters NNE D-20 On-site, ENE 550 meters ENE D-22 On-site, ESE 535 meters ESE D-29 On-site,W 630 meters W D-31 On-site, NW 1,020 meters NW D-33 3 mile ring 4,340 meters N D-35 3 mile ring 2,800 meters NE D-37 3 mile ring 2,960 meters E D-39 3 mile ring 2,510 meters SE D-42 3 mile ring 4,380 meters SSE D-43 1 mile rinq 1,590 meters SSW D-46 1 mile ring 1,580 meters WNW D-48 1 mile ring 1,680 meters NNW 13

Table 5.3 Sampling locations, Duane Arnold Energy Center (continued).

Sampling Location Code Location Description Distance and Direction from Site Stack 0-49 Lewis Access, upstream of DAEC 6,750 meters NNW 0-51 Plant DischarQe 600 meters SE D-52 Plant potable water On-site 0-53 Treated Municipal Water 13,900 meters SE D-61 Downstream of plant discharge 670 meters SSE D-83 On-site, SSE 620 meters SSE D-85 On-site, SSW 660 meters SSW D-161 ISFSI Fence East On-site 0-162 ISFSI Fence South On-site D-163 ISFSI Fence West On-site D-164 ISFSI Fence North On-site 14

Table 5.4 Type and Frequency of collection.

Location Monthly Quarterly Semiannually Annually 0-4 TLO 0-15 AP TLO G

0-16 AP G

0-17 TLO 0-18 TLO 0-20 TLO 0-22 TLD 0-29 TLO 0-31 TLO 0-33 TLO 0-35 TLO 0-37 TLO 0-39 TLO 0-42 TLO 0-43 TLO 0-46 TLO 0-48 TLO 0-49 SW BS, F 0-51 BS 0-52 WW 0-53 WW 0-61 SW F

0-83, 0-85 TLD 0-161 to 0-164 TLO 15

Table 5.5. Sample codes used in Table 5.4 and Table 5.6.

Code Description AP Airborne Particulates Al Airborne Iodine TLD Thermoluminescent Dosimeter Ml Milk WW Well Water G

Vegetation ME Meat SW Surface Water F

Fish BS River Sediment so Soil 16

Table 5.6. Program Deviations, Duane Arnold Energy Center.

Sample Type None Analysis Location(s)

Collection Date or Period 17 Comments

Table 5.7 Radiological Environmental Monitoring Program Summary.

Name of Facility Location of Facility Sample

!Type and Number of Type Analyses*

(Units)

Airborne Particulates GB 54 (pCi/m 3)

GS 8

Be-7 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Nb-95 Zr-95 Ru-103 Ru-106 Cs-134 Cs-137 Ce-141 Ce-144 TLDs (mR/quarter)

Gamma 4

Control Locations Within 0.5 mi. of Gamma 36 Stack Within 1.0 mi. of Gamma 12 Stack Within 3.0 mi.of Gamma 20 Stack ISFSI border Gamma 32 Duane Arnold Energy Center Linn, Iowa Docket No.

Reporting Period Indicator Location with Highest Annual Mean Locations LLD*

Mean (F)

• Mean (F)

• Range*

Location*

Range*

Airborne Pathway 0.003 0.024 (54/54)

D-15 0.025 (27 /27)

(0.001-0.047)

(0.011-0.047) 0.146 0.058(8/8)

D-16 0.061 (4/4)

(0.039-0.083)

(0.043-0.083) 0.0008

<LLD 0.0027

< LLD 0.0008

< LLD 0.0009

< LLD 0.0014

< LLD 0.0019

< LLD 0.0018

< LLD 0.0013

< LLD

< LLD 0.0084 0.0009

< LLD 0.0008

< LLD

< LLD 0.0016 0.0050

< LLD Direct Radiation 1.0 None D-4 15.7 (4/4)

(15.1-17.4) 1.0 16.4 (36/36)

D-17 22.0 (4/4)

(12.4-31.1)

(16.7-31.1) 1.0 16.6 (12/12)

D-46 18 9 (4/4)

(12.1 -19.9)

(16.8-19.9) 1.0 15.5 (20/20)

D-42 18.6(4/4)

(11.2-24.6)

(13.3-24.6) 1.0 43.1 (64/64)

D-ISFSl-2 (17.8-100.0) 882(4/4)

(83.1-100.0) 18 50-331 January-December, 2024 Control Number Locations Non-Mean (F) c Routine Range c Results*

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

None 0

15.7 (4/4) 0 (15.1 -17.4)

None 0

None 0

None 0

None 0

Table 5.7 Radiological Environmental Monitoring Program Summary.

Name of Facility Location of Facility Sample Type and Type Number of (Units)

Analyses

• Surface Water H-3 24 (pCi/L)

GS 24 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Nb-95 Zr-95 1-131 Cs-134 Cs-137 Ba-140 La-140 Sediments GS 4

Ci/gdry)

K-40 Mn-54 Fe-59 Co-58 Co-60 Zn-65 Nb-95 Zr-95 Ru-103 Ru-106 Cs-134 Cs-137 Ce-141 Ce-144 Duane Arnold Energy Center Linn, Iowa Indicator Locations LLD b Mean (F) '

Range '

Waterborne 188

< LLD 5.7

< LLD 10.5

< LLD 6.2

< LLD 5.3

< LLD 7.1

< LLD 6.7

< LLD 8.3

< LLD 13.2

< LLD 5.9

< LLD 5.2

< LLD 13.8

< LLD 5.6

< LLD 10.34 (2/2) 1.0 (9.38-11.30) 0.023

< LLD 0.057

< LLD 0.022

< LLD 0.019

< LLD 0.057

< LLD 0.036

< LLD 0.043

< LLD 0.026

< LLD 0.193

< LLD 0.021

< LLD 0.025

< LLD 0.056

< LLD 0.120

< LLD 19 Docket No.

Reporting Period Location with Highest Annual Mean Mean (F) '

Location*

Range '

Pathway D-51 10.34 (2/2)

(9.38-11.30) 50-331 January-December, 2024 Control Number Locations Non-Mean (F) c Routine Range c Results 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

8.62 (2/2) 0 (8.32-8.91)

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

Table 5.7 Radiological Environmental Monitoring Program Summary.

Name of Facility Location of Facility Sample Type and Type Number of (Units)

Analyses

• Ground Water, potable (pCi/L)

H-3 GS Mn-54 Fe-59 Co-58 Co-60 Zn-65 Nb-95 Zr-95 1-131 Cs-134 Cs-137 Ba-140 La-140 24 24 Broad leaf GS 2

Vegetation K-40 (pCi/gwet)

Mn-54 Fe-59 Co-58 Co-60 Zn-65 Nb-95 Zr-95 Ru-103 Ru-106 1-131 Cs-134 Cs-137 Ce-141 Ce-144 Duane Arnold Energy Center Linn, Iowa Indicator Locations LLD b Mean (F) c Range c Waterborne 188

<LLD 5.7

< LLD 10.5

< LLD 6.2

< LLD 5.3

< LLD 8.3

< LLD 8.1

< LLD 6.7

< LLD 13.2

< LLD 5.9

< LLD 5.2

< LLD 21.7

< LLD 5.6

< LLD Docket No.

Reporting Period Location with Highest Annual Mean Location*

Mean (F) c Range c Pathway Ingestion Pathway 0.05 5.63 (2/2)

D-15 7.19 (1/1)

(4.07-7.19) 0.009

< LLD 0.020

< LLD 0.007

< LLD 0.009

< LLD 0.018

< LLD 0.012

< LLD 0.016

< LLD 0.009

< LLD 0.089

< LLD 0.018

< LLD 0.009

< LLD 0.011

< LLD 0.017

< LLD 0.063

<LLD 20 50-331 January-December, 2024 Control Number Locations Non-Mean (F) c Routine Range c Results *

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

< LLD 0

None 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

Table 5.7 Radiological Environmental Monitoring Program Summary.

Duane Arnold Energy Center 50-331 Name of Facility Location of Facility Linn, Iowa Docket No.

Reporting Period January-December, 2024 (County, State)

Type and Indicator Location with Highest Annual Mean Control Sample Locations Locations Type Number of LLD b Mean (F) c Mean (F) c Mean (F) c (Units)

Analyses a Range c Location d Range c Range c Ingestion Pathway (cont.)

GS 4

Vegetation (Grain and Forage)

K-40 0.05 5.16 (4/4)

D-15 5.62 (2/2)

None (pCi/gwet)

(3.77-6.21)

(5.04-6.21)

Mn-54 0.023

< LLD Fe-59 0.035

< LLD Co-58 0.018

< LLD Co-60 0.014

< LLD Zn-65 0.046

< LLD Nb-95 0.026

< LLD Zr-95 0.037

< LLD Ru-103 0.013

< LLD Ru-106 0.177

< LLD 1-131 0.022

< LLD Cs-134 0.020

< LLD Cs-137 0.024

< LLD Ce-141 0.035

< LLD Ce-144 0.153

< LLD Fish GS 8

(pCi/gwet)

K-40 1.0 3.67 (4/4)

D-49 3.92 (4/4) 3.81 (3/3)

(3.29-4.47)

(3.61-4.30)

(3.27-4.67)

Mn-54 0.013

< LLD

< LLD Fe-59 0.031

< LLD

<LLD Co-58 0.016

< LLD

<LLD Co-60 0.019

< LLD

< LLD Zn-65 0.027

< LLD

< LLD Nb-95 0.021

< LLD

< LLD Zr-95 0.025

< LLD

< LLD Ru-103 0.020

< LLD

<LLD Ru-106 0.133

< LLD

< LLD Cs-134 0.018

< LLD

< LLD Cs-137 0.017

< LLD

< LLD Ce-141 0.033

< LLD

< LLD Ce-144 0.085

< LLD

< LLD a GB= Gross beta; GS= Gamma spectroscopy b LLD = Nominal lower limit of detection based on 4.66 sigma counting error for the background sample.

c Mean and range based upon detectable measurements only. Fraction of detectable measurements at specified locations is indicated in parentheses (F).

d Locations are specified by: (1) Name and code (Table 5.3); and (2) distance, direction and sector relative to reactor site.

• Non-routine results are those which exceed ten times the control station value for the location. If a control station value is not available, the result is considered non-routine if it exceeds ten times the preoperational value for the location.

21 Number Non-Routine Results

• 0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

Figure 5-1 Environmental Monitoring Programs Sampling Near the Duane Arnold Energy Center Small Area See Table 5.3 for sampling locations and Table 5.4 for Type and Frequency of collection.

22

Figure 5-2 Radiological Environmental Monitoring Program Sampling Stations Outside 0.5 Miles from DAEC Large Area See Table 5.3 for sampling locations and Table 5.4 for Type and Frequency of collection.

23

6.0 REFERENCES

CITED Arnold, J. R. and H. A. AI-Salih. 1955. Beryllium-7 Produced by Cosmic Rays. Science 121: 451-453.

Eisenbud, M. 1963. Environmental Radioactivity, McGraw-Hill, New York, New York, pp. 213, 275-276.

Environmental, Inc., Midwest Laboratory.

_ ___.2015 Study Plan, SP-DAEC-8001, revIsIon 24 February 12, 2015, The Operational Radiological Environmental Monitoring Program for the Duane Arnold Energy Center, Cedar Rapids, Iowa

____.2001 through 2022. Environmental Radiological Monitoring Program for the Duane Arnold Energy Center, Annual Report - Part II, Data Tabulations and Analyses, January - December, 2001 - 2019.

_ ___ 1984 to 2000. (formerly Teledyne Brown Engineering, Environmental Services, Midwest Laboratory)

Environmental Radiological Monitoring Program for the Duane Arnold Energy Center, Annual Report

- Part II, Data Tabulations and Analyses, January - December, 1983 - 1999.

____ 1982 to 1984. (formerly Hazleton Environmental Sciences Corporation) Environmental Radiation Monitoring for the Duane Arnold Energy Center, Annual Report - Part II, Data Tabulations and Analyses, January-December 1981 - 1983.

____ 2024.

Quality Manual, Rev. 10, 28 October 2024.

_ _ _ _ 2012.

Quality Assurance Program Manual, Rev. 3, 14 November 2012.

____ 2022.

Quality Control Procedures Manual, Rev. 5, 9 May 2022.

____.2009.

Quality Control Program, Rev. 2, 12 November 2009.

Microbac Laboratories-Northbrook (Before June 1, 2023 Environmental Inc.)

_ ___ 2023.

Quality Manual, Rev. 9, 25 August 2023.

Gold, S., H. W. Barkhau, 8. Shlein, and B. Kahn, 1964. Measurement of Naturally Occurring Radionuclides in Air, in the Natural Environment, University of Chicago Press, Chicago, Illinois, 369-382.

National Center for Radiological Health, 1968. Radiological Health and Data Reports, Vol. 9, Number 12, 730-746.

U. S. Department of Energy. 1978. Environmental Quarterly, Appendix E. Half-Life Tables, 1 January 1978, EML-334.

U. S. Nuclear Regulatory Commission. 1977. Regulatory Guide 1.109, Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 1 0CFR Part 50, Appendix I.

Wilson, D. W., G. M. Ward and J. E. Johnson. 1969. In Environmental Contamination by Radioactive Materials, International Atomic Energy Agency. p.125.

24

©) MICROBAC '"

700 Landwehr Road

• Northbrook, IL 60062-2310 phone (847) 564-0700

• fax (847) 564-4517 NOTE:

APPENDIX A INTERLABORATORY AND INTRALABORATORY COMPARISON PROGRAM RESULTS Appendix A is updated four times a year. The complete appendix is included in March, June, September and December monthly progress reports only.

January, 2024 through December, 2024

Appendix A lnterlaboratory/ Intra laboratory Comparison Program Results Microbac Laboratories - Northbrook (previously Environmental Inc.) has participated in interlaboratory comparison (crosscheck) programs since the formulation of its quality program in December 1971.

These programs are operated by agencies and/or companies which supply environmental sample types containing concentrations of radionuclides known to the issuing entity but not to participant laboratories.

The purpose of such a program is to provide an independent check on a laboratory's analytical procedures and to alert it of any possible problems.

Participant laboratories measure the concentration of specified radionuclides and report them to the issuing agency. Several months later, the agency reports the known values to the participant laboratories and specifies control limits. Results consistently higher or lower than the known values or outside the control limits indicate a need to check the instruments or procedures used.

Results in Table A-1 were obtained through participation in the RAD PT Study Proficiency Testing Program administered by Environmental Resource Associates, serving as a replacement for studies conducted previously by the U.S. EPA Environmental Monitoring Systems Laboratory, Las Vegas, Nevada.

Table A-2 lists results for thermoluminescent dosimeters (TLDs), via irradiation and evaluation by the University of Wisconsin-Madison Radiation Calibration Laboratory at the University of Wisconsin Medical Radiation Research Center.

Table A-3 lists results of the analyses on intralaboratory "spiked" samples for the past twelve months. All samples are prepared using NIST traceable sources. Data for previous years available upon request.

Table A-4 lists results of the analyses on intralaboratory "blank" samples for the past twelve months. Data for previous years available upon request.

Table A-5 lists analytical results from the intralaboratory "duplicate" program for the past twelve months. Acceptance is based on each result being within 25% of the mean of the two results or the two sigma uncertainties of each result overlap.

The results in Table A-6 were obtained through participation in the Mixed Analyte Performance Evaluation Program.

Results in Table A-7 were obtained through participation in the MRAD PT Study Proficiency Testing Program administered by Environmental Resource Associates, serving as a replacement for studies conducted previously by the Environmental Measurement Laboratory Quality Assessment Program (EML}.

Attachment A lists the laboratory acceptance criteria for various analyses.

Out-of-limit results are explained directly below the result.

A-1

Analysis Gamma Emitters Strontium-89, Strontium-90 Potassium-40 Gross alpha Gross beta Tritium Radium-226, Radium-228 Plutonium lodine-129, lodine-131 Nickel-63, Technetium-99, Uranium-238 lron-55 Other Analyses Attachment A ACCEPTANCE CRITERIA FOR INTRALABORATORY "SPIKED" SAMPLES Ratio of lab result to known value.

0.8 to 1.2 0.8 to 1.2 0.8 to 1.2 0.5 to 1.5 0.8 to 1.2 0.8 to 1.2 0.7 to 1.3 0.8 to 1.2 0.8 to 1.2 0.7 to 1.3 0.8 to 1.2 0.8 to 1.2 A-2

TABLE A-1. lnterlaboratory Comparison Crosscheck program, Environmental Resource Associates (ERA)".

RAD study Concentration (pCi/L)

Lab Code Date Analysis Laboratory ERA Acceptance Result Value Limits Acceptance RAD-022724M (study dates 2/27/24 - 3/11/24)

ERDW-323 10/7/2022 Ba-133 67.3 +/-4.1 79.4 62.3 -97.0 Pass ERDW-323 10/7/2022 Cs-134 20.6 +/- 2.6 30.5 18.2 -42.8 Pass ERDW-323 10/7/2022 Cs-137 221 +/- 7 212 172 -252 Pass ERDW-323 10/7/2022 Co-60 48.8 +/- 4.2 51.4 37.1 - 65.7 Pass ERDW-323 10/7/2022 Zn-65 82.6 +/- 9 216 167 -265 Fail 0 ERDW-325 10/7/2022 Gr. Alpha 15.4+/-1.6 16.9 11.1 - 22.7 Pass ERDW-325 10/7/2022 G. Beta 48.2 +/- 1.4 53.0 39.1 -66.9 Pass ERDW-321 10/7/2022 Ra-226 15.9 +/- 0.9 19.0 16.2 - 21.8 Fail c ERDW-321 10/7/2022 Ra-228 3.81 +/- 1.04 2.33 1.04 -3.60 Fail d ERDW-321 10/7/2022 Uranium 8.745 +/- 1.070 8.53 7.10 -10.0 Pass ERDW-327 4/10/2023 H-3 12,740 +/- 366 12,700 10,500 - 14,900 Pass RAD-137 Study (study dates 4/08/24 - 5/23/24)

ERDW-715 4/8/2024 Ba-133 71.2 +/- 5.5 65.9 50.1 - 81.7 Pass ERDW-715 4/8/2024 Cs-134 70.4 +/- 9.5 57.8 42.8 - 72.8 Pass ERDW-715 4/8/2024 Cs-137 188 +/- 11 186 149 - 233 Pass ERDW-715 4/8/2024 Co-60 100 +/- 10 98.8 79.7 -118 Pass ERDW-715 4/8/2024 Zn-65 231 +/- 15 240 188 - 292 Pass ERDW-713 4/8/2024 Gr. Alpha 39.4 +/- 1.9 52.6 39.6 - 65.8 Fail*

ERDW-713 4/8/2024 G. Beta 45.5 +/- 1.4 46.5 33.9 - 59.1 Pass ERDW-711 4/8/2024 Ra-226 14.3 +/- 0.8 13.4 11.10 -15.7 Pass ERDW-711 4/8/2024 Ra-228 6.01 +/- 1.19 6.24 4.2 -8.3 Pass ERDW-711 4/8/2024 Uranium 63.5 +/- 2.4 59.3 52.8 - 65.8 Pass ERDW-717 4/8/2024 H-3 20,400 +/- 448 21,300 18,200 - 24,400 Pass RAD-138 Study (study dates 7/08/24 - 8/22/24)

ERDW-1546 7/8/2024 Ba-133 41.4 +/- 5.9 38.2 25.2 - 51.2 Pass ERDW-1546 7/8/2024 Cs-134 18.6 +/- 8.0 18.9 7.81 - 30.0 Pass ERDW-1546 7/8/2024 Cs-137 54.4 +/- 13.3 57.0 32.9 -81.1 Pass ERDW-1546 7/8/2024 Co-60 82.8 +/- 7.1 76.8 59.9 - 93.7 Pass ERDW-1546 7/8/2024 Zn-65 348 +/- 30 312 253 - 371 Pass ERDW-1548 7/8/2024 Gr. Alpha 9.05 +/- 1.26 13.0 7.94 -18.1 Pass ERDW-1548 7/8/2024 G. Beta 17.3 +/- 1.0 20.6 13.2 -28.0 Pass ERDW-1552 7/8/2024 Ra-226 20.4+/-1.0 17.2 14.6 - 19.8 Fail 1 ERDW-1552 7/8/2024 Ra-228 3.72 +/- 0.96 4.63 2.88 - 6.38 Pass ERDW-1552 7/8/2024 Uranium 36.2 +/- 2.4 36.8 32.5 -41.1 Pass ERDW-1554 7/8/2024 H-3 7,840 +/- 290 7,550 5,870 - 9,230 Pass ERDW-1550 7/8/2024 1-131 20.1 +/- 0.9 27.9 24.2 - 31.6 Fail 9

• Results obtained by Microbac Laboratories Inc. - Northbrook as a participant in the crosscheck program for proficiency testing in drinking water conducted by Environmental Resource Associates (ERA).

0 An incorrect reference date was used in the calculation of the gamma emitters. If the correct date was used, all analytes would have passed ERA acceptance criteria. The Zn-65 result would have been 212 +/- 30 pCi/L.

' No obvious conclusion could be determined for the low result. It's possible that a small leak from the radon bubbler may have allowed radon gas to escape thereby leading to the low result. Subsequent ERA study RAO-137 passed for Ra-226.

• The batch recovery value as determined by the EPA method could have been biased artificially low thereby causing the result to have a high bias outside the upper acceptance limit. Subsequent ERA studies RAD-137, 138 passed for Ra-228.

• Data was reviewed but no obvious issue could be determined. Subsequent ERA study RAD-138 passed for both Gross Alpha and Gross Beta.

1 The lab continues to investigate the Ra-226 performance issues. The procedure has been revised to more closely follow the EPA method. Results are being compiled and a subsequent ERA study >MIi be ordered to validate the revised procedure.

9 ERA added stable iodine carrier to the PT sample at a concentration of 0.20 mg/L. The calculation of the results that were submitted for this study did not take this added iodine into account when calculating the chemical yield or recovery.

Incorporating the ERA added stable iodine into the calculattions; recoveries dropped from 88.32% and 90.52% to 64.56% and 66.17%. The adjusted results are: 29.42 pCi/L and 28.06 pCi/L which are both within the acceptance range.

A-3

TABLE A-2. Thermoluminescent Dosimetry, (TLD, CaSO4: Dy Cards)."

mrem Lab Code Irradiation Delivered Reportedb Performancec Date Description Dose Dose Quotient (P)

Environmental, Inc.

Group 1 2024-25-1 1/6/2025 Spike 92.0 91.8 0.00 2024-25-1 1/6/2025 Spike 2 92.0 89.7

-0.03 2024-25-1 1/6/2025 Spike 3 92.0 92.0 0.00 2024-25-1 1/6/2025 Spike 4 92.0 92.9 0.01 2024-25-1 1/6/2025 Spike 5 92.0 91.8 0.00 2024-25-1 1/6/2025 Spike 6 92.0 98.0 0.07 2024-25-1 1/6/2025 Spike 7 92.0 94.6 0.03 2024-25-1 1/6/2025 Spike 8 92.0 94.2 0.02 2024-25-1 1/6/2025 Spike 9 92.0 95.4 0.04 2024-25-1 1/6/2025 Spike 10 92.0 91.3

-0.01 2024-25-1 1/6/2025 Spike 11 92.0 89.4

-0.03 2024-25-1 1/6/2025 Spike 12 92.0 97.7 0.06 2024-25-1 1/6/2025 Spike 13 92.0 94.1 0.02 2024-25-1 1/6/2025 Spike 14 92.0 92.2 0.00 2024-25-1 1/6/2025 Spike 15 92.0 92.9 0.01 2024-25-1 1/6/2025 Spike 16 92.0 91.7 0.00 2024-25-1 1/6/2025 Spike 17 92.0 87.4

-0.05 2024-25-1 1/6/2025 Spike 18 92.0 94.7 0.03 2024-25-1 1/6/2025 Spike 19 92.0 91.0

-0.01 2024-25-1 1/6/2025 Spike 20 92.0 92.5 0.01 Mean (Spike 1-20) 92.8 0.01 Passd Standard Deviation (Spike 1-20) 2.6 0.03 Passd a TLD's were irradiated by the University of Wisconsin-Madison Radiation Calibration Laboratory following ANSI N13.37 protocol from a known air kerma rate. TLD's were read and the results were submitted by Microbac Laboratories - Northbrook to the University of Wisconsin-Madison Radiation Calibration Laboratory for comparison to the delivered dose.

b Reported dose was converted from exposure (R) to Air Kerma (cGy) using a conversion of 0.876. Conversion from air kerma to ambient dose equivalent for Cs-137 at the reference dose point H*(1 0)Ka = 1.20. mrem/cGy = 1000.

c Performance Quotient (P) is calculated as ((reported dose - conventionally true value) + conventionally true value) where the conventionally true value is the delivered dose.

d Acceptance is achieved when neither the absolute value of the mean of the P values, nor the standard deviation of the P values exceed 0.15.

A-4

TABLE A-2. Thermoluminescent Dosimetry, (TLD, CaSO4: Dy Cards).a mrem Lab Code Irradiation Delivered Reportedb Performance 0

Date Descrietion Dose Dose Quotient (Pl Environmental, Inc.

Group 2 2024-25-2 1/6/2025 Spike 21 74.0 77.5 0.05 2024-25-2 1/6/2025 Spike 22 74.0 77.6 0.05 2024-25-2 1/6/2025 Spike 23 74.0 73.2

-0.01 2024-25-2 1/6/2025 Spike 24 74.0 75.4 0.02 2024-25-2 1/6/2025 Spike 25 74.0 75.3 0.02 2024-25-2 1/6/2025 Spike 26 74.0 77.8 0.05 2024-25-2 1/6/2025 Spike 27 74.0 73.1

-0.01 2024-25-2 1/6/2025 Spike 28 74.0 74.0 0.00 2024-25-2 1/6/2025 Spike 29 74.0 75.8 0.02 2024-25-2 1/6/2025 Spike 30 74.0 76.5 0.03 2024-25-2 1/6/2025 Spike 31 74.0 73.5

-0.01 2024-25-2 1/6/2025 Spike 32 74.0 75.5 0.02 2024-25-2 1/6/2025 Spike 33 74.0 76.5 0.03 2024-25-2 1/6/2025 Spike 34 74.0 76.4 0.03 2024-25-2 1/6/2025 Spike 35 74.0 75.1 0.01 2024-25-2 1/6/2025 Spike 36 74.0 72.8

-0.02 2024-25-2 1/6/2025 Spike 37 74.0 76.0 0.03 2024-25-2 1/6/2025 Spike 38 74.0 74.9 0.01 2024-25-2 1/6/2025 Spike 39 74.0 75.4 0.02 2024-25-2 1/6/2025 Spike 40 74.0 70.8

-0.04 Mean (Spike 21-40) 75.2 0.02 Passd Standard Deviation (Spike 21-40) 1.8 0.02 Passd a TL D's were irradiated by the University of Wisconsin-Madison Radiation Calibration Laboratory following ANSI N1 3.37 protocol from a known air kerma rate. TLD's were read and the results were submitted by Microbac Laboratories - Northbrook to the University of Wisconsin-Madison Radiation Calibration Laboratory for comparison to the delivered dose.

b Reported dose was converted from exposure (R) to Air Kerma (cGy) using a conversion of 0.876. Conversion from air kerma to ambient dose equivalent for Cs-137 at the reference dose point H*(1 0)Ka = 1.20. mrem/cGy = 1000.

c Performance Quotient (P) is calculated as ((reported dose - conventionally true value) + conventionally true value) where the conventionally true value is the delivered dose.

d Acceptance is achieved when neither the absolute value of the mean of the P values, nor the standard deviation of the P values exceed 0.15.

A-5

TABLE A-3. lntralaboratory "Spiked" Samples Concentration*

Lab Codeb Reference Analysis Laboratory results Known Control Ratio Date 2s, n=1 c Activity Limitsd Acceptance Lab/Known SPDW-60025 1/12/2024 Gr. Alpha 43.3 +/- 2.4 47.9 24.0 - 57.5 Pass 0.90 SPDW-60025 1/12/2024 Gr. Beta 28.9+/-1.3 28.6 22.9 - 34.3 Pass 1.01 SPDW-60042 2/2/2024 H-3 21,225 459 22,100 17,680 - 26,520 Pass 0.96 SPDW-60059 2/14/2024 Gr. Alpha 37.6 +/- 2.8 32.2 16.1-38.6 Pass 1.17 SPDW-60059 2/14/2024 Gr. Beta 168 +/- 3 160 128.0 - 192.0 Pass 1.05 SPDW-60067 2/13/2024 H-3 20,925 451 22,100 17,680 - 26,520 Pass 0.95 SPDW-60097 2/28/2024 Gr. Alpha 27.7 +/- 2.1 32.2 16.1 - 38.6 Pass 0.86 SPDW-60097 2/28/2024 Gr. Beta 160 +/- 3 160 128.0 - 192.0 Pass 1.00 SPDW-60100 2/26/2024 H-3 21,582 +/- 462 22,100 17,680 - 26,520 Pass 0.98 SPDW-60016 3/7/2024 H-3 20,572 +/- 449 22,100 17,680 - 26,520 Pass 0.93 SPDW-60133 3/14/2024 Gr. Alpha 23.6 +/- 2.1 32.2 16.1-38.6 Pass 0.73 SPDW-60133 3/14/2024 Gr. Beta 171 +/- 3 160 128.0 - 192.0 Pass 1.07 SPDW-60150 3/22/2024 H-3 20,618 +/- 450 22,100 17,680 - 26,520 Pass 0.93 SPDW-60191 3/21 /2024 Ra-226 13.2 +/- 0.4 12.3 8.6 - 16.0 Pass 1.07 SPDW-60154 3/25/2024 Ra-228 12.7+/-1.6 15.4 10.8 - 20.0 Pass 0.82 LCS-W-052924 4/8/2024 Ba-133 55.7 +/- 4.3 65.9 52.7-79.1 Pass 0.85 LCS-W-052924 4/8/2024 Cs-134 50.1 +/- 3.4 57.8 46,2 - 69.4 Pass 0.87 LCS-W-052924 4/8/2024 Cs-137 172 +/- 6 186 149 - 223 Pass 0.92 LCS-W-052924 4/8/2024 Co-60 95.3 +/- 4.0 99 79.0 - 119 Pass 0.96 LCS-W-052924 4/8/2024 Zn-65 224 +/- 12 240 192 - 288 Pass 0.93 SPDW-60184 4/9/2024 Gr. Alpha 21.0 +/- 2.0 32.2 16.1 - 38.6 Pass 0.65 SPDW-60184 4/9/2024 Gr. Beta 158 +/- 3 160 128.0 - 192.0 Pass 0.99 SPDW-60198 4/15/2024 H-3 20,822 +/- 453 22,100 17,680 - 26,520 Pass 0.94 SPDW-60213 4/25/2024 Ra-228 15.4+/-2.0 15.3 10.7 - 19.9 Pass 1.01 SPDW-60215 4/26/2024 H-3 20,400 +/- 447 22,100 17,680 - 26,520 Pass 0.92 SPDW-60267 4/11 /2024 Ra-226 10.8 +/- 0.3 12.3 8.6 - 16.0 Pass 0.88 SPDW-60236 5/10/2024 H-3 20,415 +/- 448 22,100 17,680 - 26,520 Pass 0.92 SPDW-60253 5/16/2024 Ra-228 13.6 +/- 1.8 15.3 10.7 - 19.9 Pass 0.89 SPDW-60302 5/29/2024 Gr. Alpha 18.1 +/- 1.7 32.2 16.1 - 38.6 Pass 0.56 SPDW-60302 5/29/2024 Gr. Beta 163 +/- 3 160 128 - 192 Pass 1.02 SPDW-60307 5/23/2024 Ra-226 13.0 +/- 0.5 12.3 8.6 - 16.0 Pass 1.05 SPDW-60294 5/28/2024 H-3 20,840 +/- 463 22,100 17,680 - 26,520 Pass 0.94 SPDW-60314 6/6/2024 Ra-228 11.9 +/- 1.6 15.3 10.7 - 19.9 Pass 0.78 SPDW-60331 6/10/2024 H-3 20,602 +/- 459 22,100 17,680 - 26,520 Pass 0.93 SPDW-60357 5/30/2024 Ra-226 11.8+/-0.4 12.3 8.6 - 16.0 Pass 0.96 SPDW-60361 6/27/2024 Gr. Alpha 21.7 +/- 2.0 32.2 16.1-38.6 Pass 0.67 SPDW-60361 6/27/2024 Gr. Beta 151 +/- 2 160 128 +/- 192 Pass 0.94 SPDW-60425 6/24/2024 Ra-226 12.8 +/- 0.4 12.3 8.6 - 16.0 Pass 1.04 SPDW-60393 7/10/2024 H-3 20,368 +/- 454 22,100 17,680 - 26,520 Pass 0.92

• Liquid sample results are reported in pCi/Liter, air filters ( pCi/m3), charcoal (pCi/charcoal canister), and solid samples (pCi/kg).

b Laboratory codes: W & SPW (Water), Ml (milk), AP (air filter), SO (soil), VE (vegetation), CH (charcoal canister), F (fish), U (urine).

c Results are based on single determinations.

d Acceptance criteria are listed in Attachment A of this report.

A-6

TABLE A-3. lntralaboratory "Spiked" Samples Concentration" Lab Codeb Reference Analysis Laboratory results Known Control Ratio Date 2s, n=1° Activity Limitsd Acceptance Lab/Known SPDW-60411 7/22/2024 Gr. Alpha 18.2 +/- 1.9 32.2 16.1 - 38.6 Pass 0.57 SPDW-60411 7/22/2024 Gr. Beta 155 +/- 3 160 128 -192 Pass 0.97 SPDW-60417 7/23/2024 U (Natural) 8.14 +/- 0.92 7.36 5.15 - 9.57 Pass 1.11 SPDW-60452 7/31/2024 Ra-226 11.5+/-0.4 12.3 8.6 - 16.0 Pass 0.93 SPDW-60530 8/12/2024 Ra-226 12.3 +/- 0.4 12.3 8.6 -16.0 Pass 1.00 LCS-08/26/24 7/8/2024 Ba-133 31.2 +/- 4.3 38.2 30.6 - 45.8 Pass 0.82 LCS-08/26/24 7/8/2024 Cs-134 22.0 +/- 3.0 18.9 15.1 - 22.7 Pass 1.16 LCS-08/26/24 7/8/2024 Cs-137 68.0 +/- 6.5 57.0 45.6 - 68.4 Pass 1.19 LCS-08/26/24 7/8/2024 Co-60 80.8 +/- 5.0 76.8 61.4 - 92.2 Pass 1.05 LCS-08/26/24 7/8/2024 Zn-65 337 +/- 15 312 250 - 374 Pass 1.08 LCS-S-09/04/24 3/19/2018 Ac-228 1,122 +/- 120 1,240 992 - 1,488 Pass 0.90 LCS-S-09/04/24 3/19/2018 Bi-212 1,105 +/- 293 1,240 992 - 1,488 Pass 0.89 LCS-S-09/04/24 3/19/2018 Bi-214 1,563 +/- 49 1,760 1,408 - 2,112 Pass 0.89 LCS-S-09/04/24 3/19/2018 Co-60 7,251 +/- 94 8,060 6,448 - 9,672 Pass 0.90 LCS-S-09/04/24 3/19/2018 Pb-214 1,489 +/- 54 1,850 1,480 - 2,220 Pass 0.80 SPDW-60527 9/10/2024 H-3 20,297 +/- 453 22,100 17,680 - 26,520 Pass 0.92 SPDW-60546 9/13/2024 S-90 15.9 +/- 1.0 15.4 12.3 -18.5 Pass 1.03 SPDW-60559 9/25/2024 Gr. Alpha 7.5+/-1.1 13.0 6.5 - 15.6 Pass 0.58 SPDW-60559 9/25/2024 Gr. Beta 21.5+/-1.3 20.6 16.5 - 24.7 Pass 1.04 SPDW-60584 10/9/2024 H-3 20,016 +/- 452 22,100 17,680 - 26,520 Pass 0.91 LCS-W-090324 4/8/2024 Ba-133 65.5 +/- 5.8 65.9 53 - 79 Pass 0.99 LCS-W-090324 4/8/2024 Cs-134 54.5 +/- 5.1 57.8 46 -69 Pass 0.94 LCS-W-090324 4/8/2024 Cs-137 189 +/- 12 186 149 - 223 Pass 1.02 LCS-W-090324 4/8/2024 Co-60 101 +/- 9 98.8 79 - 119 Pass 1.02 LCS-W-090324 4/8/2024 Zn-65 260 +/- 25 240 192 - 288 Pass 1.08 LCS-W-10/03/24 8/1/2023 Cs-134 288 +/- 5 305 244 - 366 Pass 0.94 LCS-W-10/03/24 8/1/2023 Cs-137 257 +/- 8 235 188 - 282 Pass 1.09 LCS-W-10/03/24 8/1/2023 Co-57 550 +/- 16 521 417 - 625 Pass 1.06 LCS-W-10/03/24 8/1/2023 Mn-54 364 +/- 16 343 274 -412 Pass 1.06 LCS-W-10/03/24 8/1/2023 Zn-65 489 +/- 28 516 413-619 Pass 0.95 LCS-W-10/05/24 7/12/2021 Ba-133 42.5 +/- 3.5 45.5 36 - 55 Pass 0.93 LCS-W-10/05/24 7/12/2021 Cs-134 88.1 +/- 6.2 87.5 70 - 105 Pass 1.01 LCS-W-10/05/24 7/12/2021 Cs-137 219 +/- 6 208 166 - 250 Pass 1.05 LCS-W-10/05/24 7/12/2021 Co-60 88.8 +/- 5.1 87.1 70 - 105 Pass 1.02 LCS-AP-10/05/24 8/1/2022 Cs-137 52.1 +/- 2.0 47.5 38 - 57 Pass 1.10 LCS-AP-10/05/24 8/1/2022 Co-57 99.8 +/- 6.5 94.5 76 - 113 Pass 1.06 LCS-AP-10/05/24 8/1/2022 Co-60 59.9+/-2.1 57.0 46 -68 Pass 1.05 LCS-AP-10/05/24 8/1/2022 Mn-54 61.2 +/- 7.7 58.9 47 - 71 Pass 1.04 LCS-AP-10/05/24 8/1/2022 Zn-65 43.1 +/- 13.5 49.4 40 - 59 Pass 0.87

" Liquid sample results are reported in pCi/Liter, air filters ( pCi/m3), charcoal (pCi/charcoal canister), and solid samples (pCi/kg).

" Laboratory codes : W & SPW (Water), Ml (milk), AP (air filter), SO (soil), VE (vegetation), CH (charcoal canister), F (fish), U (urine).

c Results are based on single determinations.

0 Acceptance criteria are listed in Attachment A of this report.

A-7

TABLE A-3. lntralaboratory "Spiked" Samples Concentration*

Lab Code Reference Analysis Laboratory results Known Control Ratio Date 2s, n=1c Activity Limitsd Acceptance Lab/Known LCS-S-092424 3/19/2018 K-40 9,021 +/- 385 10,600 8,480 - 12720 Pass 0.85 LCS-S-092424 3/19/2018 Cs-134 4,450 +/- 235 5,330 4,264 - 6396 Pass 0.83 LCS-S-092424 3/19/2018 Cs-137 3,773 +/- 55 4,210 3,368 - 5052 Pass 0.90 LCS-S-092424 3/19/2018 Co-60 6,958 +/- 96 8,060 6,448 - 9672 Pass 0.86 LCS-S-092424 3/19/2018 Pb-214 1,638 +/- 59 1,850 1,480 - 2220 Pass 0.89 LCS-S-092424 3/19/2018 Bi-214 1,608 +/- 50 1,760 1,408-2112 Pass 0.91 LCS-S-092424 3/19/2018 Ac-228 1,105 +/- 117 1,240 992 - 1488 Pass 0.89 LCS-S-101424 2/1/2024 Co-60 15,340 +/- 87 17,820 14,256 - 21,384 Pass 0.86 LCS-S-101424 2/1/2024 Cs-134 8,700 +/- 62 8,694 6,955 - 10,433 Pass 1.00 LCS-S-101424 2/1/2024 Cs-137 37,330 +/- 26 41,850 33,480 - 50,220 Pass 0.89 LCS-S-101424 2/1/2024 K-40 11,550 +/- 411 13,095 10,476 - 15,714 Pass 0.88 LCS-S-101424 2/1/2024 Mn-54 8,080 +/- 125 8,964 7,171 - 10,757 Pass 0.90 LCS-S-101424 2/1/2024 Zn-65 16,260 +/- 273 18,981 15,185 - 22,777 Pass 0.86 LCS-W-1014224 2/1/2024 Co-57 544 +/- 24 554 443 - 664 Pass 0.98 LCS-W-1014224 2/1/2024 Cs-134 281 +/- 8 289 231 - 347 Pass 0.97 LCS-W-1014224 2/1/2024 Cs-137 254 +/- 11 257 205 - 308 Pass 0.99 LCS-W-1014224 2/1/2024 Mn-54 369 +/- 21 365 292 - 437 Pass 1.01 LCS-W-1014224 2/1/2024 Zn-65 501 +/- 38 489 391 - 586 Pass 1.03 LCS-VE-100524 2/1/2024 Co-57 544 +/- 5 521 417 - 625 Pass 1.04 LCS-VE-100524 2/1/2024 Cs-134 281 +/- 8 305 244 - 366 Pass 0.92 LCS-VE-100524 2/1/2024 Cs-137 254 +/- 11 235 188 - 282 Pass 1.08 LCS-VE-100524 2/1/2024 Zn-65 501 +/- 38 516 413 - 619 Pass 0.97 LCS-VE-100524 2/1/2024 Mn-54 369 +/- 21 343 274 - 411 Pass 1.08 SPDW-60583 10/9/2024 H-3 20,016 +/- 452 22,100 17,680 - 26,520 Pass 0.91 SPDW-60604 10/25/2024 H-3 19,814 +/- 447 22,100 17,680 - 26,520 Pass 0.90 SPDW-60622 11/14/2024 Gr. Alpha 12.5 +/- 2.9 13.0 6.5 - 15.6 Pass 0.96 SPDW-60622 11/14/2024 Gr. Beta 17.8 +/- 2.3 20.6 16.5 - 24.7 Pass 0.86 SPDW-60635 10/10/2024 Ra-226 14.9 +/- 0.5 12.3 8.6 - 16.0 Pass 1.21 SPDW-60631 12/2/2024 H-3 20,384 +/- 453 22,100 17,680 - 26,520 Pass 0.92 SPDW-60641 12/17/2024 H-3 21,520 +/- 468 22,100 17,680 - 26,520 Pass 0.97

• Liquid sample results are reported in pCi/Liter, air filters ( pCi/m3), charcoal (pCi/charcoal canister), and solid samples (pCi/kg).

vegetation (pCi/sample) b Laboratory codes: W & SPW (Water), Ml (milk), AP (air filter), SO (soil), VE (vegetation), CH (charcoal canister), F (fish), U (urine).

c Results are based on single determinations.

d Acceptance criteria are listed in Attachment A of this report.

A-8

TABLE A-4. lntralaboratory "Blank" Samples Concentration*

Lab Codeb Sample Collection Analysis<

Laboratory results (4.66cr)

Acceptance Type Date LLD Activiti Criteria (4.66 cr)

SPDW-60024 Water 1/12/2024 Gr. Alpha 0.70 0.14 +/- 0.50 2

SPDW-60024 Water 1/12/2024 Gr. Beta 0.83

-0.60 +/- 0.56 4

SPW-3913 Water 2/2/2024 Tc-99 11.8

-12.3 +/- 7.0 200 SPDW-60041 Water 2/2/2024 H-3 177 68 +/- 96 200 SPDW-60058 Water 2/14/2024 Gr. Alpha 0.51

-0.10 +/- 0.35 2

SPDW-60058 Water 2/14/2024 Gr. Beta 0.71 0.19 +/-0.50 4

SPDW-60147 Water 2/21/2024 Ra-226 0.04 0.18 +/- 0.03 2

SPDW-60099 Water 2/26/2024 H-3 179

-89 +/- 84 200 SPDW-60097 Water 2/28/2024 Gr. Alpha 0.53 0.29 +/- 0.39 2

SPDW-60097 Water 2/28/2024 Gr. Beta 0.79

-0.42 +/- 0.54 4

SPDW-60141 Water 3/19/2024 1-131 0.18

-0.10 +/-0.10 SPDW-60149 Water 3/22/2024 H-3 174

-2 +/- 86 200 SPDW-60115 Water 3/7/2024 H-3 175 20 +/- 85 200 SPDW-60129 Water 3/11/2024 Ra-228 0.74 0.07 +/- 0.35 2

SPDW-60132 Water 3/14/2024 Gr. Alpha 0.51

-0.20 +/- 0.34 2

SPDW-60132 Water 3/14/2024 Gr. Beta 0.75

-0.07 +/- 0.52 4

SPDW-60190 Water 3/21/2024 Ra-226 0.04

-0.14 +/- 0.03 2

SPDW-60155 Water 3/25/2024 Ra-228 1.46

-0.1 3 +/-0.66 2

SPDW-60183 Water 4/9/2024 Gr. Alpha 0.66

-0.09 +/- 0.46 2

SPDW-60183 Water 4/9/2024 Gr. Beta 0.76 0.11 +/- 0.54 4

SPDW-60266 Water 4/11/2024 Ra-226 0.04

-0.15 +/- 0.03 2

SPDW-60197 Water 4/15/2024 H-3 174 53 +/- 84 200 SPDW-60212 Water 4/25/2024 Ra-228 0.90 0.03 +/- 0.42 2

SPDW-60214 Water 4/26/2024 H-3 170 27 +/- 80 200 SPDW-60235 Water 5/10/2024 H-3 174

-7 +/- 81 200 SPDW-60252 Water 5/16/2024 Ra-228 0.68 0.72 +/- 0.39 2

SPDW-60294 Water 5/28/2024 H-3 188

-43 +/- 88 200 SPDW-60295 Water 5/28/2024 Sr-89 0.62 0.16 +/-0.44 5

SPDW-60295 Water 5/28/2024 Sr-90 0.66

-0.20 +/- 0.28 SPDW-60301 Water 5/29/2024 Gr. Alpha 0.49

-0.16 +/-0.33 2

SPDW-60301 Water 5/29/2024 Gr. Beta 0.76 0.14 +/- 0.54 4

SPDW-60306 Water 5/23/2024 Ra-228 0.17

-0.30 +/- 0.38 2

SPDW-60356 Water 5/30/2024 Ra-226 0.04 0.12 +/- 0.03 2

SPDW-60313 Water 6/6/2024 Ra-228 0.76

-0.01 +/- 0.35 2

SPDW-60330 Water 6/10/2024 H-3 183 12 +/- 85 200 SPDW-60340 Water 6/17/2024 1-131 0.15

-0.04 +/- 0.08 SPDW-60360 Water 6/27/2024 Gr. Alpha 0.46

-0.12 +/-0.31 2

SPDW-60360 Water 6/27/2024 Gr. Beta 0.75 0.10 +/- 0.53 4

SPDW-60424 Water 6/24/2024 Ra-226 0.04

-0.1 4 +/-0.09 2

• Liquid sample results are reported in pCi/Liter, air filters ( pCi/m 3), charcoal (pCi/charcoal canister), and solid samples (pCi/g).

b Laboratory codes : W & SPW (Water), Ml (milk), AP (air filter), SO (soil), VE (vegetation), CH (charcoal canister), F (fish), U (urine).

c l-131(G); iodine-131 as analyzed by gamma spectroscopy.

d Activity reported is a net activity result.

A-9

TABLE A-4. lntralaboratory "Blank" Samples Concentration" Lab Codeb Sample Collection Analysisc Laborato!}'. results (4.66cr)

Acceptance Type Date LLD Activit/1 Criteria (4.66 cr)

SPDW-60392 Water 7/10/2024 H-3 183

-28 +/- 83 200 SPDW-60411 Water 7/22/2024 Gr. Alpha 0.42

-0.06 +/- 0.29 2

SPDW-60411 Water 7/22/2024 Gr. Beta 0.71 0.40 +/- 0.51 4

SPDW-60416 Water 7/23/2024 U (Natural) 0.56

-0.16 +/-0.66 1

SPDW-60418 Water 7/24/2024 Ra-228 0.65 0.93 +/- 0.40 2

SPDW-60451 Water 7/31/2024 Ra-226 0.07 0.02 +/- 0.06 2

SPW-1901 Water 8/6/2024 Ni-63 87

-144 +/- 51 200 SPDW-60462 Water 8/16/2024 Ra-228 0.58 0.08 +/- 0.28 2

SPDW-60529 Water 8/12/2024 Ra-226 0.04

-0.07 +/- 0.03 2

SPDW-60522 Water 9/5/2024 1-131 0.11

-0.09 +/- 0.07 SPDW-60526 Water 9/10/2024 H-3 183 9 +/- 86 200 SPDW-60592 Water 9/11/2024 Ra-226 0.06

-0.11 +/- 0.05 2

SPDW-60545 Water 9/13/2024 Sr-89 0.56

-0.06 +/- 0.43 5

SPDW-60545 Water 9/13/2024 Sr-90 0.52 0.06 +/- 0.25 1

SPDW-60560 Water 9/26/2024 H-3 180 88 +/- 89 200 SPDW-60594 Water 10/16/2024 Ra-228 0.73 0.43 +/- 0.39 2

SPDW-60634 Water 10/10/2024 Ra-226 0.05

-0.07 +/- 0.04 2

MB-102124 Water 10/21/2024 Co-57 4.76 0.87 +/- 2.53 10 MB-102124 Water 10/21/2024 Cs-134 3.88

-3.36 +/- 2.68 10 MB-102124 Water 10/21/2024 Cs-137 5.73 1.08 +/- 2.64 10 MB-102124 Water 10/21/2024 Mn-54 5.17 0.03 +/- 2.65 10 MB-102124 Water 10/21/2024 Zn-65 6.83

-1.76+/-5.61 10 SPDW-60614 Water 11/8/2024 H-3 185

-29 +/- 84 200 SPDW-60630 Water 12/2/2024 H-3 184

-12 +/- 86 200 MB-120924 Water 12/9/2024 Co-57 1.08 0.04 +/- 0.66 10 MB-120924 Water 12/9/2024 Cs-134 1.06 0.22 +/- 0.61 10 MB-120924 Water 12/9/2024 Cs-137 1.39 0.65 +/- 0.68 10 MB-120924 Water 12/9/2024 Mn-54 0.93 0.07 +/- 0.55 10 MB-120924 Water 12/9/2024 Zn-65 2.28 0.33 +/- 1.12 10 MB-121224 Water 12/12/2024 Co-57 1.56

-1.64 +/- 1.28 10 MB-121224 Water 12/12/2024 Cs-134 1.85

-2.84 +/- 1.36 10 MB-121224 Water 12/12/2024 Cs-137 1.39

-0.10 +/- 1.44 10 MB-121224 Water 12/12/2024 Mn-54 2.56 1.81 +/- 1.30 10 MB-121224 Water 12/12/2024 Zn-65 3.05

-6.22 +/- 2.99 10 SPDW-60638 Water 12/12/2024 1-131 0.17

-0.19 +/- 0.08 SPDW-60641 Water 12/17/2024 H-3 182 3 +/- 85 200

• Liquid sample results are reported in pCi/Liter, air filters ( pCi/m3J, charcoal (pCi/charcoal canister), and solid samples (pCi/g).

b Laboratory codes : W & SPW (Water), Ml (milk), AP (air filter), SO (soil), VE (vegetation), CH (charcoal canister), F (fish), U (urine).

c l-131(G); iodine-131 as analyzed by gamma spectroscopy.

d Activity reported is a net activity result.

A-10

TABLE A-5. lntralaboratory "Duplicate" Samples Concentration" Collection Averaged Lab Codeb Date Analysis First Result Second Result Result Acceptance DW-60006 1/5/2024 Gr. Alpha 2.03 +/- 0.83 1.59 +/- 0.83 1.81 +/- 0.59 Pass DW-60006 1/5/2024 Gr. Beta 1.36 +/- 0.58 1.22 +/- 0.62 1.29 +/- 0.42 Pass W-41 1/5/2024 Ra-226 1.67 +/- 0.35 1.03 +/- 0.35 1.35 +/- 0.25 Pass W-41 1/5/2024 Ra-228 4.19+/-0.85 3.45 +/- 0.83 3.82 +/- 0.59 Pass W-62 1/8/2024 Ra-226 0.54 +/- 0.30 0.12 +/- 0.41 0.33 +/- 0.25 Pass DW-60018 1/16/2024 Gr. Alpha 1.75 +/- 0.74 0.98 +/- 0.80 1.37 +/- 0.54 Pass W-125,126 1/16/2024 Ra-226 0.37 +/- 0.18 0.66 +/- 0.27 0.52 +/-0.16 Pass DW-60034,60035 1/29/2024 Gr. Alpha 2.10 +/- 0.74 1.41 +/- 0.79 1.76 +/- 0.54 Pass DW-60034,60035 1/29/2024 Gr. Beta 1.13 +/- 0.57 0.57 +/- 0.57 0.85 +/- 0.40 Pass DW-60049,60050 2/5/2024 Gr. Alpha 0.61 +/- 1.02 1.20 +/- 0.87 0.90 +/- 0.67 Pass DW-60049,60050 2/5/2024 Gr. Beta 0.99 +/- 0.64 1.19 +/- 0.07 1.09 +/- 0.32 Pass DW-60054,60055 2/8/2024 Gr. Beta 0.25 +/- 0.53 0.62 +/- 0.61 0.44 +/- 0.40 Pass DW-60071,60072 2/16/2024 Ra-226 2.33 +/- 0.21 1.73 +/- 0.17 2.03 +/- 0.14 Pass DW-60071,60072 2/16/2024 Ra-228 0.48 +/- 0.42 0.60 +/- 0.45 0.54 +/- 0.31 Pass DW-60107,60108 3/2/2024 Gr. Alpha 1.26 +/- 0.98 1.59 +/- 0.99 1.42 +/- 0.70 Pass DW-60107,60108 3/2/2024 Gr. Beta 0.63 +/- 0.57 0.14 +/-0.59 0.38 +/- 0.41 Pass DW-60120,60121 3/8/2024 Gr. Beta 1.15+/-0.56 1.04 +/- 0.58 1.10+/-0.40 Pass LW-582,583 3/19/2024 Be-7 3.80 +/- 0.70 1.76 +/- 0.60 2.78 +/- 0.46 Pass SWT-708,709 3/26/2024 H-3 186 +/- 90 136 +/- 87 161 +/- 62 Pass SW-624,625 4/2/2024 H-3 1,174 +/- 133 1,302 +/- 138 1,238 +/- 96 Pass AP-865,866 4/3/2024 Be-7 0.040 +/- 0.007 0.053 +/- 0.008 0.047 +/- 0.005 Pass DW-60180,60181 4/5/2024 Ra-226 0.97 +/- 0.25 1.30 +/- 0.21 1.135 +/-0.16 Pass DW-60180,60181 4/5/2024 Ra-228 0.85 +/- 0.48 1.34 +/- 0.54 1.095 +/- 0.36 Pass WW-949,950 4/16/2024 H-3 229 +/- 94 136 +/- 90 183 +/- 65 Pass S-886,887 4/18/2024 Pb-214 0.93 +/- 0.04 0.94 +/- 0.04 0.93 +/- 0.03 Pass S-886,887 4/18/2024 Ac-228 0.82 +/- 0.08 0.83 +/- 0.06 0.82 +/- 0.05 Pass DW-60206,60207 4/19/2024 Ra-226 2.35 +/- 0.27 3.49 +/- 0.25 2.92 +/- 0.18 Pass DW-60203,60204 4/19/2024 Gr. Alpha 2.12 +/- 0.64 1.74 +/-0.73 1.93 +/- 0.49 Pass DW-60206,60207 4/19/2024 Ra-228 0.50 +/- 0.59

-0.21 +/- 0.53 0.15 +/-0.40 Pass WW-1075,1076 4/30/2024 H-3 278 +/- 107 311 +/-109 294 +/- 76 Pass SG-1017,1018 5/1/2024 Gr. Alpha 27.2 +/- 4.00 32.0 +/- 4.00 29.6 +/- 2.83 Pass SG-1017,1018 5/1/2024 Gr. Beta 25.7 +/- 1.80 24.5 +/- 1.90 25.1 +/- 1.31 Pass SG-1017,1018 5/1/2024 Pb-214 3.28 +/- 0.14 4.61 +/- 0.11 3.95 +/- 0.09 Pass SG-1017,1018 5/1/2024 Ac-228 4.86 +/- 0.18 4.98 +/- 0.37 4.92 +/- 0.21 Pass DW-60273,60274 5/21/2024 Ra-228 2.12 +/- 0.63 1.33 +/- 0.45 1.73 +/- 0.39 Pass XW-1138,1139 5/31/2024 H-3 732 +/- 124 688 +/- 122 710 +/- 87 Pass A-11

TABLE A-5. lntralaboratory "Duplicate" Samples Concentration*

Collection Averaged Lab Codeb Date Analysis First Result Second Result Result Acceptance AP-060324A,B 6/3/2024 Gr. Beta 0.021 +/- 0.005 0.018 +/- 0.005 0.020 +/- 0.003 Pass AP-061224A,B 6/12/2024 Gr. Beta 0.009 +/- 0.003 0.011 +/- 0.003 0.010 +/- 0.002 Pass AP-061724A,B 6/17/2024 Gr. Beta 0.031 +/- 0.005 0.023 +/- 0.005 0.027 +/- 0.004 Pass AP-062524A,B 6/25/2024 Gr. Beta 0.033 +/- 0.003 0.034 +/- 0.003 0.034 +/- 0.002 Pass SG-1432,1433 6/24/2024 Ra-226 2.36 +/- 0.09 2.36 +/- 0.08 2.36 +/- 0.06 Pass SG-1432,1433 6/24/2024 Ra-228 1.67+/-0.14 1.69 +/- 0.15 1.68 +/- 0.10 Pass SG-1472,1473 7/1/2024 Gr. Alpha 36.0 +/- 4.5 36.8 +/- 4.5 36.4 +/- 3.2 Pass SG-1472,1473 7/1/2024 Gr. Beta 30.4 +/- 2.1 31.2 +/- 2.2 30.8 +/- 1.5 Pass SG-1472,1473 7/1/2024 Pb-214 2.64 +/- 0.11 3.11 +/- 0.09 2.88 +/- 0.07 Pass SG-1472,1473 7/1/2024 Ac-228 5.55 +/- 0.21 5.79 +/- 0.25 5.67 +/- 0.16 Pass SG-1474,1475 7/1/2024 Gr. Alpha 43.6 +/- 5.7 37.5 +/- 5.4 40.6 +/- 3.9 Pass SG-1474,1 475 7/1/2024 Gr. Beta 40.6 +/- 2.8 34.2 +/- 2.7 37.4+/-1.9 Pass SG-1474, 1475 7/1/2024 Pb-214 3.58 +/- 0.10 3.93 +/- 0.10 3.76 +/- 0.07 Pass SG-1474,1475 7/1/2024 Ac-228 4.21 +/- 0.15 4.13 +/- 0.16 4.17 +/- 0.11 Pass AP-070324A,B 7/3/2024 Gr. Beta 0.013 +/- 0.003 0.014 +/- 0.003 0.013 +/- 0.002 Pass W-1 592,1593 7/9/2024 Gr. Alpha 1.23 +/- 0.67 0.36 +/- 0.54 0.80 +/- 0.43 Pass W-1592,1593 7/9/2024 Gr. Beta 1.45 +/- 0.60 0.60 +/- 0.53 1.03 +/- 0.40 Pass AP-071024A,B 7/10/2024 Gr. Beta 0.024 +/- 0.003 0.025 +/- 0.003 0.024 +/- 0.002 Pass S-1613,1614 7/11 /2024 Pb-214 197 +/- 1 200 +/- 1 199 +/- 1 Pass S-1613,1614 7/11 /2024 Ac-228 134 +/- 1 143 +/- 1 139 +/- 1 Pass AP-071724A,B 7/17/2024 Gr. Beta 0.038 +/- 0.001 0.032 +/- 0.003 0.035 +/- 0.001 Pass SG-1722, 1723 7/22/2024 Gr. Beta 16.4 +/- 3.4 17.5 +/- 3.4 16.9 +/- 2.4 Pass SG-1722, 1723 7/22/2024 Gr. Alpha 25.5 +/- 6.9 17.5 +/- 6.0 21.5 +/- 4.6 Pass SG-1722, 1723 7/22/2024 K-40 6.99 +/- 1.04 5.75 +/- 0.86 6.37 +/- 0.67 Pass SG-1722,1723 7/22/2024 Pb-214 7.62 +/-0.18 8.10 +/- 0.25 7.86 +/- 0.15 Pass SG-1 722,1723 7/22/2024 Ac-228 4.72 +/- 0.34 4.76 +/- 0.36 4.74 +/- 0.24 Pass DW-60413,60414 7/22/2024 Gr. Alpha 1.71 +/- 0.79 0.93 +/- 0.81 1.32 +/- 0.56 Pass DW-60413,60414 7/22/2024 Gr. Beta 1.18+/-0.58 1.26 +/- 0.59 1.22 +/- 0.41 Pass AP-080524A,B 8/5/2024 Gr. Beta 0.025 +/- 0.003 0.025 +/- 0.003 0.025 +/- 0.002 Pass AP-081324A,B 8/13/2024 Gr. Beta 0.030 +/- 0.004 0.028 +/- 0.004 0.029 +/- 0.003 Pass AP-082124A,B 8/21/2024 Gr. Beta 0.034 +/- 0.003 0.030 +/- 0.003 0.032 +/- 0.002 Pass AP-082824A,B 8/28/2024 Gr. Beta 0.033 +/- 0.003 0.034 +/- 0.003 0.033 +/- 0.002 Pass AP-090924A,B 9/9/2024 Gr. Beta 0,025 +/- 0.005 0.026 +/- 0.005 0.026 +/- 0.003 Pass SO-2132,2133 9/9/2024 Be-7 0.39 +/- 0.11 0.53 +/- 0.22 0.46 +/-0.12 Pass SO-2132,2133 9/9/2024 K-40 14.78 +/- 0.27 14.52 +/- 0.52 14.65 +/- 0.29 Pass SO-2132,2133 9/9/2024 Cs-137 0.10 +/- 0.01 0.08 +/- 0.02 0.09 +/- 0.01 Pass SO-2132,2133 9/9/2024 Tl-208 0.44 +/- 0.03 0.43 +/- 0.02 0.44 +/- 0.02 Pass SO-2132,2133 9/9/2024 Bi-212 1.40 +/- 0.34 1.25 +/- 0.15 1.32 +/- 0.19 Pass SO-2132,2133 9/9/2024 Bi-214 1.01 +/- 0.03 0.90 +/- 0.04 0.95 +/- 0.02 Pass SO-2132,2133 9/9/2024 Pb-212 1.29 +/- 0.02 1.18 +/-0.03 1.24 +/- 0.02 Pass SO-2132,2133 9/9/2024 Pb-214 0.88 +/- 0.03 1.07 +/- 0.03 0.98 +/- 0.02 Pass A-12 L

TABLE A-5. lntralaboratory "Duplicate" Samples Concentration*

Collection Averaged Lab Codeb Date Anal~sis First Result Second Result Result Acceetance SO-2132,2133 9/9/2024 Ra-226 2.38 +/- 0.36 2.31 +/- 0.16 2.34 +/- 0.20 Pass SO-2132,2133 9/9/2024 Ac-228 1.33 +/- 0.10 1.33 +/- 0.06 1.33 +/- 0.06 Pass SS-2206,2207 9/17/2024 Be-7 0.29 +/- 0.06 0.23 +/- 0.10 0.26 +/- 0.06 Pass SS-2206,2207 9/17/2024 K-40 6.54 +/- 0.29 6.19 +/-0.20 6.37 +/- 0.18 Pass SS-2206,2207 9/17/2024 Tl-208 0.20 +/- 0.02 0.22 +/- 0.02 0.21 +/- 0.01 Pass SS-2206,2207 9/17/2024 Bi-212 0.65 +/-0.14 0.69 +/- 0.19 0.67 +/-0.12 Pass SS-2206,2207 9/17/2024 Bi-214 0.68 +/- 0.02 0.61 +/- 0.02 0.65 +/- 0.02 Pass SS-2206,2207 9/17/2024 Pb-212 0.51 +/- 0.02 0.59 +/- 0.02 0.55 +/- 0.01 Pass SS-2206,2207 9/17/2024 Pb-214 0.73 +/- 0.03 0.63 +/- 0.02 0.68 +/- 0.02 Pass SS-2206,2207 9/17/2024 Ra-226 1.12+/-0.12 1.25 +/- 0.19 1.18 +/-0.11 Pass SS-2206,2207 9/17/2024 Ac-228 0.66 +/- 0.05 0.65 +/- 0.06 0.66 +/- 0.04 Pass VE-2111,2112 9/10/2024 Be-7 0.56 +/- 0.17 0.59 +/- 0.18 0.58 +/-0.12 Pass VE-2111,2112 9/10/2024 K-40 4.62 +/- 0.40 5.21 +/- 0.41 4.91 +/- 0.29 Pass AP-091624A,B 9/16/2024 Gr. Beta 0.044 +/- 0.004 0.043 +/- 0.004 0.044 +/- 0.002 Pass SS-2206,2207 9/17/2024 Be-7 0.29 +/- 0.06 0.23 +/- 0.10 0.26 +/- 0.06 Pass SS-2206,2207 9/17/2024 K-40 6.54 +/- 0.29 6.19 +/- 0.20 6.37 +/- 0.18 Pass SS-2206,2207 9/17/2024 Tl-208 0.20 +/- 0.02 0.22 +/- 0.02 0.21 +/- 0.01 Pass SS-2206,2207 9/17/2024 Bi-212 0.65 +/- 0.14 0.69+/-0.19 0.67 +/-0.12 Pass SS-2206,2207 9/17/2024 Bi-214 0.68 +/- 0.02 0.61 +/- 0.02 0.65 +/- 0.02 Pass SS-2206,2207 9/17/2024 Pb-212 0.51 +/- 0.02 0.59 +/- 0.02 0.55 +/- 0.01 Pass SS-2206,2207 9/17/2024 Pb-214 0.73 +/- 0.03 0.63 +/- 0.02 0.68 +/- 0.02 Pass SS-2206,2207 9/17/2024 Ra-226 1.12+/-0.12 1.25 +/- 0.19 1.18 +/-0.11 Pass SS-2206,2207 9/17/2024 Ac-228 0.66 +/- 0.05 0.65 +/- 0.06 0.66 +/- 0.04 Pass VE-2111,2112 9/10/2024 Be-7 0.56 +/- 0.17 0.59 +/-0.18 0.58 +/- 0.12 Pass VE-2111,2112 9/10/2024 K-40 4.62 +/- 0.40 5.21 +/- 0.41 4.91 +/- 0.29 Pass AP-092524A,B 9/25/2024 Gr. Beta 0.036 +/- 0.003 0.033 +/- 0.003 0.035 +/- 0.002 Pass AP-2773,2774 9/30/2024 Be-7 0.067 +/- 0.008 0.075 +/- 0.066 0.071 +/- 0.033 Pass SG-2353,2354 10/3/2024 K-40 3.68 +/- 0.34 2.79 +/- 0.59 3.24 +/- 0.34 Pass SG-2353,2354 10/3/2024 Tl-208 0.13 +/- 0.01 0.14 +/- 0.03 0.13 +/- 0.01 Pass SG-2353,2354 10/3/2024 Pb-212 0.36 +/- 0.02 0.27 +/- 0.03 0.32 +/- 0.02 Pass SG-2353,2354 10/3/2024 Pb-214 1.64 +/- 0.05 1.21 +/- 0.08 1.43 +/- 0.05 Pass SG-2353,2354 10/3/2024 Bi-214 1.56 +/- 0.05 1.32 +/- 0.10 1.44 +/- 0.06 Pass SG-2353,2354 10/3/2024 Ac-228 2.62 +/- 0.09 2.20 +/- 0.19 2.41 +/-0.11 Pass SG-2362,2363 10/4/2024 Gr. Alpha 31.50 +/- 3.70 23.00 +/- 3.30 27.25 +/- 2.48 Pass SG-2362,2363 10/4/2024 Gr. Beta 24.70 +/- 1.70 19.60 +/- 1.60 22.15 +/- 1.17 Pass SG-2362,2363 10/4/2024 Ra-226 4.08 +/- 0.23 4.03 +/-0.18 4.06 +/- 0.15 Pass SG-2362,2363 10/4/2024 Ra-228 5.90 +/- 0.41 5.85 +/- 0.34 5.88 +/- 0.27 Pass S-2541,2542 10/11/2024 K-40 14.20 +/- 0.44 14.82 +/- 0.44 14.51 +/- 0.31 Pass S-2541,2542 10/11/2024 Cs-137 0.08 +/- 0.01 0.10 +/- 0.01 0.09 +/- 0.01 Pass S-2541,2542 10/11/2024 Tl-208 0.26 +/- 0.02 0.27 +/- 0.02 0.27 +/- 0.01 Pass S-2541,2542 10/11/2024 Pb-212 0.75 +/- 0.03 0.54 +/- 0.03 0.64 +/- 0.02 Pass A-13

TABLE A-5. lntralaboratory "Duplicate" Samples Lab Codeb S-2541,2542 S-2541,2542 S-2541,2542 S-2752,2753 S-2752,2753 S-2752,2753 S-2752,2753 S-2752,2753 S-2752,2753 S-2752,2753 S-2752,2753 S-2752,2753 F-2899,2900 SW-2815,2816 SW-3046,3047 W-3067,3068 AP-3335,3336 Collection Date 10/11/2024 10/11/2024 10/11/2024 10/24/2024 10/24/2024 10/24/2024 10/24/2024 10/24/2024 10/24/2024 10/24/2024 10/24/2024 10/24/2024 11/6/2024 11/5/2024 12/4/2024 12/3/2024 12/30/2024 Analysis Bi-212 Pb-214 Ac-228 K-40 Cs-137 Tl-208 Pb-212 Bi-212 Pb-214 Bi-214 Ra-226 Ac-228 K-40 H-3 H-3 H-3 Be-7 First Result 1.17 +/-0.29 1.28 +/- 0.05 0.88 +/- 0.08 15.24 +/- 0.33 0.09 +/- 0.09 0.33 +/- 0.01 0.93 +/- 0.02 1.15 +/-0.12 1.33 +/- 0.03 1.37 +/- 0.04 2.61 +/- 0.36 1.10 +/- 0.07 2.38 +/- 0.35 265 +/- 100 109 +/- 91 206 +/- 96 0.034 +/- 0.005 Concentration*

Second Result 0.83 +/- 0.16 1.07 +/- 0.05 0.85 +/- 0.08 15.54 +/- 0.31 0.10+/-0.09 0.34 +/- 0.01 0.98 +/- 0.02 1.13 +/- 0.12 1.19 +/- 0.03 1.19 +/-0.03 2.28 +/- 0.15 1.10 +/- 0.04 3.06 +/- 0.13 214 +/- 97 178 +/- 94 329 +/- 102 0.050 +/- 0.005 Averaged Result 1.00 +/-0.16 1.17 +/- 0.04 0.86 +/- 0.06 15.39 +/- 0.22 0.09 +/- 0.06 0.34 +/- 0.01 0.96 +/- 0.01 1.14 +/- 0.08 1.26 +/- 0.02 1.28 +/- 0.03 2.45 +/- 0.20 1.10 +/- 0.04 2.72 +/- 0.18 240 +/- 70 144 +/- 65 268 +/- 70 0.042 +/- 0.003 Note: Duplicate analyses are performed on every twentieth sample received. Results are not listed for those analyses with activities that measure below the LLD.

• Results are reported in units of pCi/L, except for air filters (pCi/Filter or pCi/m3), food products, vegetation, soil and sediment (pCi/g).

b AP (Air Particulate), AV (Aquatic Vegetation), BS (Bottom Sediment), CF (Cattle Feed), CH (Charcoal Canister),

Acceptance Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass OW (Drinking Water), E (Egg), F (Fish), G (Grass), LW (Lake Water), Ml (Milk), P (Precipitation), PM (Powdered Milk),

S (Solid), SG (Sludge), SO (Soil), SS (Shoreline Sediment), SW (Surface Water), SWT (Surface Water Treated),

SWU (Surface Water Untreated), U (Urine), VE (Vegetation), W (Water), WW (Well Water).

A-14

TABLE A-6. Department of Energy's Mixed Analyte Performance Evaluation Program (MAPEP).

Concentration*

Reference Known Acceptance Lab Code b Date Analysis Laboratory result Activity Range c Acceptance MADW-429 2/1/2024 Gross Alpha 0.641 +/-0.048 1.01 0.30 - 1.72 Pass MADW-429 2/1/2024 Gross Beta 4.71 +/- 0.08 5.6 2.79 - 8.36 Pass MADW-457 2/1/2024 Cs-134 0.09 +/- 0.19 0

NA C Pass MADW-457 2/1/2024 Cs-137 11.1 +/- 0.4 9.7 6.8-12.6 Pass MADW-457 2/1/2024 Co-57 26.4 +/- 0.4 25.4 17.8 - 33.0 Pass MADW-457 2/1/2024 Co-60 11.2 +/- 0.3 10.27 7.19 -13.35 Pass MADW-457 2/1/2024 Mn-54 8.23 +/- 0.39 7.36 5.15 - 9.57 Pass MADW-457 2/1/2024 Zn-65 0.10 +/- 0.30 0

NA C Pass MADW-457 2/1/2024 K-40 3.16 +/- 2.49 0

NA C Pass MADW-457 2/1/2024 Ra-226 0.46 +/- 0.07 0.310 0.217 - 0.403 Fail d MAAP-459 2/1/2024 Cs-134 0.03 +/- 0.03 0

NA C Pass MAAP-459 2/1/2024 Cs-137 1.30 +/- 0.07 1.48 1.04 - 1.92 Pass MAAP-459 2/1/2024 Co-57 0.58 +/- 0.03 0.819 0.573 - 1.065 Pass MAAP-459 2/1/2024 Co-60 1.30 +/- 0.06 1.64 1.15 - 2.13 Pass MAAP-459 2/1/2024 Mn-54 0.51 +/- 0.05 0.555 0.389 - 0.722 Pass MAAP-459 2/1/2024 Zn-65 0.27 +/- 0.07 0.332 NA e Pass MASO-461 2/1/2024 Cs-134 345 +/- 2 404 283 - 525 Pass MASO-461 2/1/2024 Cs-137 1539 +/- 7 1550 1085 - 2015 Pass MASO-461 2/1/2024 Co-57 355 +/- 4 401 281 - 521 Pass MASO-461 2/1/2024 Co-60 619 +/- 4 660 462 - 858 Pass MASO-461 2/1/2024 Mn-54 332 +/- 13 332 232 - 432 Pass MASO-461 2/1/2024 Zn-65 543 +/- 9 703 492 - 914 Pass MASO-461 2/1/2024 K-40 510 +/- 20 485 340 - 631 Pass MAVE-464 2/1/2024 Cs-134 2.97 +/- 0.08 3.67 2.57 - 4.77 Pass MAVE-464 2/1/2024 Cs-137 2.36 +/- 0.15 2.57 1.80 - 3.34 Pass MAVE-464 2/1/2024 Co-57 1.78 +/- 0.09 2.53 1.77 - 3.29 Pass MAVE-464 2/1/2024 Co-60 2.61 +/- 0.13 2.96 2.07 - 3.85 Pass MAVE-464 2/1/2024 Mn-54 0.03 +/- 0.07 0

NAC Pass MAVE-464 2/1/2024 Zn-65 6.41 +/- 0.30 8.02 5.61 - 10.43 Pass A-15

TABLE A-6. Department of Energy's Mixed Analyte Performance Evaluation Program (MAPEP).

Concentration" Reference Known Acceptance Lab Code b Date Analysis Laboratory result Activity Range c Acceptance MADW-2185 8/1/2024 Gross Alpha 0.88 +/- 0.01 1.29 0.39 - 2.19 Pass MADW-2185 8/1/2024 Gross Beta 4.35 +/- 0.01 5.09 2.55 - 7.64 Pass MASO-2187 8/1/2024 Cs-134 330 +/- 4 417 292 - 542 Pass MASO-2187 8/1/2024 Cs-137 1650 +/- 11 1650 1155 - 2145 Pass MASO-2187 8/1/2024 Co-57 311 +/- 5 330 231 - 429 Pass MASO-2187 8/1/2024 Co-60 669 +/ 700 490 - 910 Pass MASO-2187 8/1/2024 Mn-54 116 +/- 5 113 79 - 147 Pass MASO-2187 8/1/2024 Zn-65 330 +/- 8 415 291 - 540 Pass MASO-2187 8/1/2024 K-40 531 +/- 31 525 368 - 683 Pass MADW-2183 8/1/2024 Cs-134 19.9 +/- 0.3 22.3 15.6 - 29.0 Pass MADW-2183 8/1/2024 Cs-137 0.99 +/- 0.29 0

NA c,e Fail MADW-2183 8/1/2024 Co-57 25.3 +/- 0.4 26.4 18.5 - 34.3 Pass MADW-2183 8/1/2024 Co-60 14.7 +/- 0.4 15.0 10.5 - 19.5 Pass MADW-2183 8/1/2024 Mn-54 0.12 +/- 0.16 0

NA C Pass MADW-2183 8/1/2024 Zn-65 20.6+/-1.0 22.8 16.00 - 29.60 Pass MADW-2183 8/1/2024 K-40 8.92 +/- 1.23 0

NA c,e Fail MAAP-2191 8/1/2024 Cs-134 0.254 +/- 0.030 0.334 0.234 - 0.434 Pass MAAP-2191 8/1/2024 Cs-137 0.260 +/- 0.046 0.269 0.188 -0.350 Pass MAAP-2191 8/1/2024 Co-57

-0.0003 +/- 0.0126 0

NA C Pass MAAP-2191 8/1/2024 Co-60 0.333 +/- 0.045 0.361 0.253 - 0.469 Pass MAAP-2191 8/1/2024 Mn-54

-0.003 +/- 0.022 0

NA C Pass MAAP-2191 8/1/2024 Zn-65

-0.002 +/- 0.054 0

NA C Pass MAVE-2189 8/1/2024 Cs-134 2.10 +/- 0.07 2.89 2.02 - 3.76 Pass MAVE-2189 8/1/2024 Cs-137 1.53 +/- 0.11 1.91 1.34 - 2.48 Pass MAVE-2189 8/1/2024 Co-57 0.003 +/- 0.023 0

NA C Pass MAVE-2189 8/1/2024 Co-60 1.54 +/- 0.08 2.01 1.41 - 2.61 Pass MAVE-2189 8/1/2024 Mn-54 2.89 +/- 0.15 3.53 2.47 - 4.59 Pass MAVE-2189 8/1/2024 Zn-65 7.14 +/-0.29 9.13 6.39 - 11.87 Pass a Results are reported in units of Bq/kg (soil), Bq/L (water) or Bq/total sample (filters, vegetation).

b Laboratory codes as follows: MAW (water), MADW (water), MAAP (air filter), MASO (soil) and MAVE (vegetation).

c MAPEP results are presented as the known values and expected laboratory precision (1 sigma, 1 determination) and control limits as defined by the MAPEP. A known value of "zero" indicates an analysis was included in the testing series as a "false positive". MAPEP does not provide an acceptance range.

d No conclusive reason for the failure could be determined. The uncertainty overlapped the known activity (reference value).

• False positive detections could have occurred due to a combination of an inadequate background subtraction for this sample geometry compounded by a very long analysis time.

A-16

TABLE A-7. lnterlaboratory Comparison Crosscheck Program, Environmental Resource Associates (ERA)".

MRAD-40 Study Concentration

• Lab Code b Date Analysis Laboratory ERA Acceptance Result Value c Limits d Acceptance ERAP-574 3/18/2024 Cs-134 291 +/- 4 273 177 - 335 Pass ERAP-574 3/18/2024 Cs-137 131 +/- 6 106 87 - 139 Pass ERAP-574 3/18/2024 Co-60 1240 +/- 8 1120 952 - 1420 Pass ERAP-574 3/18/2024 Mn-54

< 3.1

< 35.0 0.00 - 35.0 Pass ERAP-574 3/18/2024 Zn-65 102 +/- 9 77.2 63.3 - 118 Pass ERAP-574 3/18/2024 Sr-90 173 +/- 5 158 99.9 - 215 Pass ERAP-600 3/18/2024 Gross Alpha 110 +/- 3 95.9 50.1 -158 Pass ERAP-600 3/18/2024 Gross Beta 31.7+/-1.6 22.2 13.5 - 33.5 Pass

• Results obtained by Microbac Laboratories - Northbrook as a participant in the crosscheck program for proficiency testing administered by Environmental Resource Associates, serving as a replacement for studies conducted previously by the Environmental Measurements Laboratory Quality Assessment Program (EML).

b Laboratory code ERAP (air filter). Results are reported in units of (pCi/Filter).

c The ERA Assigned values for the air filter standards are equal to 100% of the parameter present in the standard as determined by the gravimetric and/or volumetric measurements made during standard preparation as applicable.

d The acceptance limits are established per the guidelines contained in the Department of Energy (DOE) report EML-564, Analysis of Environmental Measurements Laboratory (EML) Quality Assessment Program (QAP)

Data Determination of Operational Criteria and Control Limits for Performance Evaluation Purposes or ERA's SOP for the generation of Performance Acceptance Limits.

A-17

©) MICROBAC "

700 Landwehr Road

• Northbrook, IL 60062-2310 phone (847) 564-0700

• fax (847) 564-4517 Appendix B Data Reporting Conventions

APPENDIX B.

DATA REPORTING CONVENTIONS Data Reporting Conventions 1.0. All activities, except gross alpha and gross beta, are decay corrected to collection time or the end of the collection period.

2.0. Single Measurements Each single measurement is reported as follows:

x +/- s where:

x = value of the measurement; s = 2cr counting uncertainty (corresponding to the 95% confidence level).

In cases where the activity is less than the lower limit of detection L, it is reported as: < L, where L = the lower limit of detection based on 4.66cr uncertainty for a background sample.

3.0. Duplicate analyses If duplicate analyses are reported, the convention is as follows. :

3.1 Individual results: For two analysis results; x1 +/- s1 and x2 +/- s2 Reported result:

x +/- s; where x = (1/2) (x1 + x2) ands= (1/2),Js~ + Si 3.2.

3.3.

Individual results:

< L1, < L2 Individual results:

x +/- s, < L 4.0. Computation of Averages and Standard Deviations Reported result: < L, where L = lower of L1 and L2 Reported result:

x +/- s if x 2: L; < L otherwise.

4.1 Averages and standard deviations listed in the tables are computed from all of the individual measurements over the period averaged; for exa~ple, an annual standard deviation would not be the average of quarterly standard deviations. The average x and standard deviation "s" of a set of n numbers x1, x2... xn are defined as follows:

4.2 Values below the highest lower limit of detection are not included in the average.

4.3 If all values in the averaging group are less than the highest LLD, the highest LLD is reported.

4.4 If all but one of the values are less than the highest LLD, the single value x and associated two sigma error is reported.

4.5 In rounding off, the following rules are followed:

4.5.1. If the number following those to be retained is less than 5, the number is dropped, and the retained numbers are kept unchanged. As an example, 11.443 is rounded off to 11.44.

4.5.2.

If the number following those to be retained is equal to or greater than 5, the number is dropped and the last retained number is raised by 1. As an example, 11.445 is rounded off to 11.45.

B-1

@ MICROBAC "

700 Landwehr Road

• Northbrook, ll 60062-2310 phone (847) 564-0700

• fax (847) 564-4517 Appendix C Maximum permissible concentrations of radioactivity in air and water above natural background in unrestricted areas

APPENDIX C Table C-1.

Maximum permissible concentrations of radioactivity in air and water above natural background in unrestricted areas 8

Air (pCi/m 3

)

Water (pCi/L)

Gross alpha 1 X 10-3 Strontium-89 8,000 Gross beta Strontium-90 500 lodine-131 b 2.8 X 10-1 Cesium-137 1,000 Barium-140 8,000 lodine-131 1,000 Potassium-40 c 4,000 Gross alpha 2

Gross beta 10 Tritium 1 X 10 6

a Taken from Table 2 of Appendix 8 to Code of Federal Regulations Title 10, Part 20, and appropriate footnotes.

Concentrations may be averaged over a period not greater than one year.

b Value adjusted by a factor of 700 to reduce the dose resulting from the air-grass-cow-milk-child pathway.

c A natural radionuclide.

C-1

APPENDIX D.

SUMMARY

OF THE LAND USE CENSUS No Land Use Census was performed in 2024.

APPENDIX E. ANNUAL RADIATION DOSE ASSESSMENT The annual offsite radiation dose to a member of the public was determined by assessment of environmental dosimetry results and by calculations based on monitored effluent releases.

Calculated Dose from Effluent Releases:

The contribution of dose to a member of the public most likely to be exposed from liquid and gaseous effluent releases was calculated. The calculation methods follow those prescribed by Regulatory Guide 1.109, "Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I".

Results of the Gaseous and Liquid Effluents are reported in the 2024 Annual Radiological Material Release Report.

Dose Contribution from Direct Radiation:

Direct radiation dose from the operation of the DAEC was reported by TLDs placed at locations in the surrounding environment as described in the Defueled Offsite Dose Assessment Manual (DODAM).

As stated in Part 1 of this report, no plant effect was indicated by the TLDs when dose results were compared to the estimated average natural background for the central United States.

==

Conclusion:==

A review of the calculation of offsite doses, the appropriateness of REMP sampling station types and locations was compared to requirements in Regulatory Guide 4.8 Environmental Technical. The current sampling scheme was determined to be adequate for the identified receptors.

There is no Appendix I limit for direct radiation. Compliance with 40 CFR 190 limits of 25 mrem whole body and 75 mrem thyroid is demonstrated in the Duane Arnold Energy Center 2024 Annual Radiological Environmental Operating Report, subsections "Ambient Radiation (TLDs)" and "ISFSI Facility Operations Monitoring".