ML24131A097

Annual Radiological Environmental Operating Report 2023

ML24131A097
Person / Time
Site:	Palo Verde
Issue date:	04/10/2024
From:	Dilorenzo M Arizona Public Service Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
102-08805-MDD/MSG
Download: ML24131A097 (1)

Text

Technical Specification 5.6.2 5.6.2

Palo Verde Nuclear Generating Station P.O. Box 52034 102-08805-MDD/MSG Phoenix, AZ 85072 April 10, 2024 Mail Station 7636 Tel: (623) 393-3495

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Palo Verde Nuclear Generating Station Units 1, 2, and 3 Renewed Operating License Nos. NPF-41, NPF-51, and NPF-74 Docket Nos. STN 50-528, STN 50-529, and STN 50-530 Annual Radiological Environmental Operating Report 2023

Enclosed please find the Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2, and 3 Annual Radiological Environmental Operating Report for 2023. Arizona Public Service Company is submitting this report pursuant to the PVNGS Technical Specification Reporting Requirement, Section 5.6.2.

No new commitments are being made to the Nuclear Regulatory Commission by this letter.

Should you need further information regarding this submittal, please contact me at (623) 393-3495.

Sincerely, Dilorenzo, Michael Digitally signed by Dilorenzo, Michael D(Z99838) D(Z99838)

Date: 2024.05.10 08:33:33 -07'00' Michael D. DiLorenzo Department Leader Nuclear Regulatory Affairs

MDD/MSG/cr

Enclosure:

Palo Verde Nuclear Generating Station Annual Radiological Environmental Operating Report 2023

cc: J. Monninger NRC Region IV Regional Administrator W. T. Orders NRC NRR Project Manager for PVNGS L. N. Merker NRC Senior Resident Inspector for PVNGS B. D. Goretzki Bureau Chief, Bureau of Radiation Control - Arizona Department of Health Services

A member of the STARS Alliance LLC Callaway

• Diablo Canyon

• Palo Verde

• Wolf Creek Enclosure Palo Verde Nuclear Generating Station Annual Radiological Environmental Operating Report 2023

PALO VERDE NUCLEAR GENERATING STATION ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING 2023

(

Reference:

RCTSAI 1643, Legacy Item No.036843.01)

Rhodes, James Digitally signed by Rhodes, James E(Z01681)

Prepared by: _________ E(Z01681) Date: 2024.05.09 06:52:40 -07'00'

Senior Health Physicist Radiological Engineering Donnelly, Patrick Digitally signed by Donnelly, Patrick T(Z32986)

Reviewed by: ________ T(Z32986) Date: 2024.05.09 08:08:05 -07'00' Supervisor, Radiological Engineering Digitally signed by Grusecki, Lori Grusecki, Lori J(Z39643) J(Z39643)

Approved by: ________ Date: 2024.05.09 08:40:32 -07'00' Director, Technical Support/Manager, Radiation Protection

1. TABLE OF CONTENTS

1. Introduction............................................................................................................................. 2 1.1 Overview.......................................................................................................................... 2 1.2 Radiation and Radioactivity............................................................................................. 3

2. Description of the Monitoring Program.................................................................................. 4 2.1 Radiological Environmental Monitoring Program........................................................... 4 2.2 Radiological Environmental Monitoring Program Changes for 2023............................. 4 2.3 REMP Deviations/Abnormal Events Summary............................................................... 4 2.4 Groundwater Protection................................................................................................... 5

3. Sample Collection Program.................................................................................................. 14 3.1 Water.............................................................................................................................. 14 3.2 Vegetation...................................................................................................................... 14 3.3 Milk................................................................................................................................ 14 3.4 Air................................................................................................................................... 14 3.5 Soil, Sludge, and Sediment............................................................................................ 14

4. Analytical Procedures........................................................................................................... 15 4.1 Air Particulate................................................................................................................ 15 4.1.1 Gross Beta.................................................................................................................... 15 4.1.2 Gamma Spectroscopy.................................................................................................. 15 4.2 Airborne Radioiodine..................................................................................................... 15 4.2.1 Gamma Spectroscopy.................................................................................................. 15 4.3 Milk................................................................................................................................ 15 4.3.1 Gamma Spectroscopy.................................................................................................. 15 4.3.2 Radiochemical I-131 Separation.................................................................................. 15 4.4 Vegetation...................................................................................................................... 15 4.4.1 Gamma Spectroscopy.................................................................................................. 15 4.5 Sludge/Sediment............................................................................................................. 16 4.5.1 Gamma Spectroscopy.................................................................................................. 16 4.6 Water.............................................................................................................................. 16 4.6.1 Gamma Spectroscopy.................................................................................................. 16 4.6.2 Tritium......................................................................................................................... 16 4.6.3 Gross Beta.................................................................................................................... 16 PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page ii 4.7 Soil................................................................................................................................. 16 4.7.1 Gamma Spectroscopy.................................................................................................. 16

5. Nuclear Instrumentation........................................................................................................ 17 5.1 Gamma Spectrometer..................................................................................................... 17 5.2 Liquid Scintillation Spectrometer.................................................................................. 17 5.3 Gas Flow Proportional Counter...................................................................................... 17

6. Isotopic Detection Limits and Reporting Criteria................................................................. 18 6.1 Lower Limits of Detection............................................................................................. 18 6.2 Data Reporting Criteria.................................................................................................. 18 6.3 LLD and Reporting Criteria Overview.......................................................................... 18

7. Interlaboratory Comparison Program................................................................................... 22 7.1 Quality Control Program................................................................................................ 22 7.2 Intercomparison Results................................................................................................. 22

8. Data Interpretation and Conclusions..................................................................................... 24 8.1 Air Particulates............................................................................................................... 24 8.2 Airborne Radioiodine..................................................................................................... 24 8.3 Vegetation...................................................................................................................... 24 8.4 Milk................................................................................................................................ 25 8.5 Drinking Water............................................................................................................... 25 8.6 Groundwater................................................................................................................... 25 8.7 Surface Water................................................................................................................. 25 8.8 Sludge and Sediment...................................................................................................... 26 8.8.1 Water Resources Centrifuge Waste Sludge................................................................. 26 8.8.2 Cooling Tower Sludge................................................................................................. 26 8.9 Data Trends.................................................................................................................... 26 8.10 Hard-To-Detect Radionuclide Results........................................................................ 26

9. Thermoluminescent Dosimeter (TLD) Results and Data..................................................... 48

10. Land Use Census................................................................................................................ 53 10.1 Introduction................................................................................................................ 53 10.2 Census Results............................................................................................................ 53

11. Summary and Conclusions................................................................................................ 58

12. References.......................................................................................................................... 62

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page iii LIST OF TABLES

Table 2-1 Sample Collection Locations.......................................................................................... 7 Table 2-2 Sample Collection Schedule........................................................................................... 8 Table 2-3 Summaries of the REMP Deviations/Abnormal Events................................................ 9 Table 6-1 ODCM Required Lower Limits of Detection (a priori)............................................... 20 Table 6-2 ODCM Required Reporting Levels.............................................................................. 21 Table 6-3 Typical MDA Values................................................................................................... 21 Table 7-1 Interlaboratory Comparison Results............................................................................. 23 Table 8-1 Particulate Gross Beta in Air - First and Second Quarters.......................................... 27 Table 8-2 Particulate Gross Beta in Air - Third and Forth Quarters............................................ 28 Table 8-3 Gamma in Air Filter Composites................................................................................. 29 Table 8-4 Radioiodine in Air - First and Second Quarters.......................................................... 30 Table 8-5 Radioiodine in Air - Third and Forth Quarters............................................................ 31 Table 8-6 Vegetation..................................................................................................................... 32 Table 8-7 Milk.............................................................................................................................. 33 Table 8-8 Drinking Water............................................................................................................. 34 Table 8-9 Groundwater................................................................................................................. 36 Table 8-10 Surface Water............................................................................................................. 37 Table 8-11 Sludge/Sediment......................................................................................................... 42 Table 8-12 Hard -To-Detect Radionuclide Results...................................................................... 43 Table 9-1 TLD Site Locations...................................................................................................... 49 Table 9-2 Environmental TLD Results......................................................................................... 50 Table 10-1 Land Use Census........................................................................................................ 54 Table 11-1 Environmental Radiological Monitoring Program Annual Summary........................ 59

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page iv TABLE OF FIGURES

Figure 1-1 Sources of Radiation Exposure in the United States..................................................... 3 Figure 2-1 REMP Sample Sites-Map (0-10 miles)...................................................................... 12 Figure 2-2 REMP Sample Sites-Map (10-35 Miles)................................................................... 13 Figure 8-1 Gross Beta in Air, 1st-2nd Quarters............................................................................ 44 Figure 8-2 Gross Beta in Air, 3rd-4th Quarters............................................................................ 44 Figure 8-3 Historical Gross Beta in Air (Weekly System Average)............................................ 45 Figure 8-4 Historical Gross Beta in Air (Annual Site to Site Comparisons) Compared to Pre-Op

....................................................................................................................................................... 45 Figure 8-5 Gross Beta in Drinking Water..................................................................................... 46 Figure 8-6 Evaporation Pond Tritium Activity (Pre-Op-2008)................................................... 46 Figure 8-7 Evaporation Pond Tritium Activity (2017-2023)........................................................ 47 Figure 8-8 Sedimentation Basin 2 Cs-137.................................................................................... 47 Figure 9-1 Network Environmental TLD Exposure Rates........................................................... 51 Figure 9-2 Environmental TLD Comparison: Pre-Operational versus 2023................................ 52 Figure 10-1 Historical Comparison of Nearest Resident Dose..................................................... 55 Figure 10-2 Historical Comparison of Nearest Milk Animal Dose.............................................. 56 Figure 10-3 Historical Comparison of Nearest Garden Dose....................................................... 57

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page v ABSTRACT

The Radiological Environmental Monitoring Program (REMP) is an ongoing program conducted by Arizona Public Service Company (APS) for the Palo Verde Nuclear Generating Station (PVNGS). Various types of environmental samples are collected near PVNGS and analyzed for plant-related radionuclide concentrations.

During 2023, the following categories of samples were collected by APS:

• Broadleaf vegetation

• Groundwater

• Drinking water

• Surface water

• Airborne particulate and radioiodine

• Goat milk

• Sludge

Thermoluminescent dosimeters (TLDs) were used to measure environmental gamma radiation.

The Environmental TLD program is also conducted by APS.

The Arizona Department of Health Services, Bureau of Radiation Control (BRC) performs radiochemistry analyses on various duplicate samples provided to them by APS. Samples analyzed by BRC include onsite samples from the Reservoirs, Evaporation Ponds, and two (2)

Deep Wells. Offsite samples analyzed by BRC include two (2) local resident wells. BRC also performs air sampling at seven (7) offsite locations identical to APS and maintains approximately fifty (50) environmental TLD monitoring locations, eighteen (18) of which are duplicates of APS locations.

A comparison of pre-operational and operational data indicates no changes to environmental radiation levels.

(NOTE: Reference to APS throughout this report refers to PVNGS personnel)

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 1

1. Introduction

This report presents the results of the operational Radiological Environmental Monitoring Program conducted by Arizona Public Service Company (APS). The Radiological Environmental Monitoring Program (REMP) was established for the Palo Verde Nuclear Generating Station (PVNGS) by APS in 1979.

This report contains the measurements and findings for 2023. All references are specifically identified in Section 12.

1.1 Overview

The Radiological Environmental Monitoring Program ( R E M P ) provides representative measurements of radiation and radioactive materials in exposure pathways. The REMP measures radionuclides that lead to the highest potential radiation exposures to members of the public resulting from station operation. This monitoring program implements Title 10 of the Code of Federal Regulations (CFR) Part 50, Appendix I,Section IV.B.2., and thereby supplements the radiological effluent monitoring program by verifying that the measurable concentrations of radioactive materials and levels of radiation are not higher than expected based on the effluent measurements and the modeling of the environmental exposure pathways. Guidance for this monitoring program is provided by the US Nuclear Regulatory Commission (USNRC) in their Radiological Assessment Branch Technical Position on Environmental Monitoring, Revision 1, November 1979 (incorporated into NUREG 1301). Results from the REMP help to evaluate sources of elevated levels of radioactivity in the environment (i.e., atmospheric nuclear detonations or abnormal plant releases).

The Land Use Census ensures that changes in the use of areas at, and beyond the site boundary, are identified and that modifications to the REMP are made if required by the results of this census. This census satisfies the requirements of Section IV.B.3 of Appendix I to 10 CFR Part 50.

The Interlaboratory Comparison Program is provided to ensure that independent checks on the precision and accuracy of the measurements of radioactive material in environmental sample matrices. The interlaboratory comparisons are performed as part of the quality assurance program for environmental monitoring to demonstrate that the results are valid for the purposes of 10 CFR 50, Appendix I, Section IV.B.2.

Results of the PVNGS pre-operational environmental monitoring program are presented in Reference 1.

The initial criticality of Unit 1 occurred May 25, 1985. Initial criticality for Units 2 and 3 were April 18, 1986, and October 25, 1987, respectively. PVNGS operational findings (historical) are presented in Reference 2.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 2 1.2 Radiation and Radioactivity

Atoms are the basic building blocks of matter. Unstable atoms emit radiation; material that spontaneously emits radiation is referred to as radioactive. Radioactive material is frequently categorized as either Natural or Man-made.

Some sources of radiation exist naturally in the environment and include radon, thoron, cosmic, terrestrial, and internal. The sun and stars are sources of cosmic radiation. Atmospheric conditions, the Earths magnetic field, and differences in elevation can affect the amount of cosmic radiation an individual receives, also referred to as dose. The Earth is a source of terrestrial radiation. Uranium, thorium, and radium exist naturally in rock and soil. All organic matter contains carbon and potassium, and water contains small amounts of dissolved uranium and thorium.

The largest contributor of dose to Americans from natural sources is attributed to radon. Radon is naturally released from rocks, soil and water and found in air. All people are a source of internal radiation. Potassium-40 and carbon-14 are radioactive nuclides and inside all people from birth, making people a source of exposure.

Man-made sources of radiation include consumer products, such as smoke detectors, thorium lantern mantles, color televisions, potassium salt and even tobacco. Some other consumer products that are sources of radiation include building and road construction materials, and combustible fuels, such as gas and coal. Nuclear medicine such as x-rays, diagnostic imaging, and therapeutic procedures are all widely used. Some of the occupational areas that result in individual exposures to radiation include radiography, radiation oncology, commercial power generation and research laboratories. Personnel radiation exposures are tracked in accordance with rules and regulations set forth by the Nuclear Regulatory Commission (NRC). The NRC requires licensees to limit radiation exposures to 5,000 mrem per year, Total Effective Dose Equivalent (TEDE). The largest contributor to personnel radiation exposure from man-made sources come from diagnostic x-rays, and from medical sources, such as Iodine-131, Thallium-201, Technetium-99m and Cesium-134.

The NRC and the U.S. Environmental Protection Agency both state that the average member of the public receives an annual exposure of 620 mrem from ionizing radiation. Approximately half of the exposure is attributed to manmade sources and the other half to natural sources. Figure 1-1 illustrates the contribution of various sources of radiation and the contribution to exposure in the United States (NCRP Report No. 160 (2009)).

Figure 1-1 Sources of Radiation Exposure in the United States

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 3

2. Description of the Monitoring Program

APS and vendor organizations performed the pre-operational Radiological Environmental Monitoring Program between 1979 and 1985. APS and vendors continued the program into the operational phase.

2.1 Radiological Environmental Monitoring Program

The assessment program consists of routine measurements of environmental gamma radiation and radionuclide concentrations in media such as air, groundwater, drinking water, surface water, vegetation, milk, sludge, and sediment.

`Samples are collected by APS at the monitoring sites shown in Figures 2-1 and 2-2. The specific sample types, sampling locations, and sampling frequencies, as set forth in the PVNGS Offsite Dose Calculation Manual (ODCM), Reference 4, are presented in Tables 2-l, 2-2, and 9-1.

Additional onsite sampling (outside the scope of the ODCM) is performed to supplement the REMP. Results are included in this report. Routine sample analyses were performed at the onsite Central Chemistry Laboratory and Operating Unit laboratories. Analyses for hard-to-detect radionuclides were performed by GEL Laboratories LLC.

Environmental gamma radiation measurements were performed by APS using TLDs at fifty (50) locations near PVNGS. The PVNGS Dosimetry Department is accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) to process personnel ionizing radiation dosimeters.

In addition to monitoring environmental media, a Land Use Census is performed annually to identify the nearest milk animals, residents, and gardens. This information is used to evaluate the potential dose to members of the public for those exposure pathways that are indicated.

2.2 Radiological Environmental Monitoring Program Changes for 2023

Changes to the REMP were identified in December 2023. These changes are reflected in the Offsite Dose Calculation Manual (ODCM) revision 31, which became effective in March 2024.

These changes include the addition of a milk and vegetation donor, which is reflected in the ODCM as Site #66. Also changed is the number of ground water wells, which changed from 4 to

3. The decrease in the number of wells is because of 1 well being removed from service.

Changes were made to the 0 - 10 miles map for clarification and ease of use.

2.3 REMP Deviations/Abnormal Events Summary

During calendar year 2023, there were twenty-four (24) deviations/abnormal events pertaining to the monitoring program. Refer to Table 2-3 for more detail and corrective actions taken.

There were three (3) events involving environmental dosimetry in 2023. A Neutron dosimeter used to monitor location 69 indicated an anomalous reading. An investigation found that there were 6Li10BO phosphors adhered one of the Teflon substrates, causing non-radiation induced luminescence. This TLD reading is invalid. The dosimeter was removed from service. Neutron

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 4 dosimeters are placed in the field to verify the absence of neutron radiation and are not part of the REMP reporting criteria. One event involving environmental dosimetry was documented because of a missing stanchion, along with the assigned dosimeters used for monitoring location 12 during the third quarter. The stanchion was replaced along with the two dosimeters. The final event was for location 1 during the third quarter. The dosimeter was found to have been damaged, and the reading was invalid. The dosimeter results were not used in analysis and the TLD was removed from service.

Three (3) events were recorded because of the LLD not being achieved. Two of the events occurred on March 21, 2023. Both were attributed to incorrect procedure usage regarding count times. One of the locations was the Sedimentation Basin #2, and the other was the Water Reclamation Facility (WRF) Influent. One event when the LLD was not met for Cs-134 for WRF centrifuge waste sludge. The sample reading of 152 pCi/L was just over the LLD of 150 pCi/L.

This sample is not required by the ODCM; however, WR Influent Samples are collected to analyze for non-plant related radionuclides.

There were (3) three events related to the collection and analysis of Milk samples. One February sample, and one for December were not collected. Both were attributed to scheduling errors. One event occurred due when a software anomaly caused a LLD to not be achieved. The analysis stopped prior to enough time to meet the LLD.

Vegetation samples for the month of February were not collected. Both were attributed to scheduling errors. Air sample data collected during this period confirms that there were no abnormal results during this time and no impact to the Environment. In the other event, the LLD of 60 pCi/kg for I-131 was not achieved for Site 62. The MDA achieved was 62 pCi/L.

There were ten (10) events within the air sampling program during 2023. Five of the events were pertaining to Estimated Time Meters, or ETM.

Twelve (12) events occurred during 2023 pertaining to Air Sampling. Of these, one ETM failure was recorded at location 17A for weeks 20 and 21. Both counts were considered valid due to normal dust loading. An ETM failure for was found to have occurred at location 21 for week 26 (6/20/2023-6/27/23). The sample media did appear to have normal dust loading, and the volume was calculated based on the documented run time. A ETM malfunction was recorded at Location 21 for week 27 (7/05/2023). One event was recorded a ETM failure for the week 7/5/23 to 7/11/2023 (week 28) at Location 21. The following week, the ETM failed at Location 21 again.

This failure was for the period of 7/11/2023 to 7/18/2023 (week 29). This locations ETM failure was also documented in weeks 26 and 27. Location 17A was found to be without power for week 16 and therefore, no sample was available. Site 21 air sampler experienced a vein failure for week 25. This sample is not valid, as it did not normal dust loading. There were two (2) sample pump failures that occurred during 2023: One failure was for week 49 at Location 21.

The other pump failure occurred during week 50 at Location 4.

2.4 Groundwater Protection

PVNGS has implemented a groundwater protection initiative developed by the Nuclear Energy Institute (NEI). The implementing guidance of this initiative, NEI 07-07 (Industry Ground Water Protection Initiative - Final Guidance Document, August 2007), and later

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 5 revised in March of 2019, provides added assurance that groundwater will not be adversely affected by PVNGS operations.

In 2018, following a revision, several of the wells included in the PVNGS REMP program were removed from mandated sampling. Now referred to as Legacy Wells, they continue to be sampled for data continuity and in support of the Groundwater Protection Initiative. Sample results for the shallow aquifer wells are reported in the PVNGS Annual Radioactive Effluent Release Report (ARERR). The Area Wide Aquifer Protection Permit (APP) No. 100388-89315 was revised in December 2023. The new permit is APP P-100388-98240 and reflects the efforts to institute advanced evaporation technology. There is no degradation to the Groundwater Protection Program.

Three subsurface samples were obtained, one each from Units 2 and 3 tritium monitoring wells, and one from the shallow aquifer outside of the Unit 1 Radiologically Controlled Area (RCA).

These samples were analyzed for hard-to-detect radionuclides (i.e., C-14, Fe-55, Ni-63, Sr-90) as verification that there are no underground leaks from plant systems that may affect groundwater. All results were <MDA. Refer to Table 8-12 for sample results.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 6 Table 2-1 Sample Collection Locations SAMPLE SITE # SAMPLE TYPE LOCATION (a) LOCATION DESCRIPTION 4 Air E16 APS Office 6A* Air SSE13 Old US 80 7A Air ESE3 Arlint Ave. and Buckeye-Salome Rd. gton School 14A Air NNE2 371s 15 Air NE2 NE Site Boundary 17A Air E3 351st Ave.

21 Air S3 S Site Boundary 29 Air W1 W Site Boundary 35 Air NNW8 Tonopah 40 Air N2 Transmission Rd 46 Drinking Water NNW8 Local resident 47 Vegetation N3 Local resident 48 Drinking Water SW1 Local resident Drinking Water 49 Milk-goat N2 Local resident Vegetation 53* Milk-goat NE30 Local resident 54 Milk-goat NNE4 Local resident 55 Drinking Water resident (Supplemental) SW3 Local 57 Groundwater ONSITE Well 27ddc 58 Groundwater ONSITE Well 34abb 58A Groundwater ONSITE Well 27dcb 59 Surface Water ONSITE Evaporation Pond 1A 60 Surface Water ONSITE 85 Acre Reservoir 61 Surface Water ONSITE 45 Acre Reservoir 62* Vegetation ENE26 Commercial Farm 63 Surface Water ONSITE Evaporation Pond 2A 64 Surface Water ONSITE Evaporation Pond 3A 65 Groundwater ONSITE Well 34aab NOTES:

• Designates a control site (a) D i r e c t i o n a n d d istances are from the centerline of Unit 2 containment and rounded to the nearest mile.

Air sample sites designated with the letter A are sites that have the same site number as a TLD location, but are not in the same location (i.e., site #6 TLD location is different from site #6A air sample location; site #4 TLD location is the same as site #4 air sample location)

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 7 Table 2-2 Sample Collection Schedule

SAMPLE AIRBORNE AIRBORNE GROUND DRINKING SURFACE SITE # PARTICULATE MILK RADIOIODINE VEGETATION WATER WATER WATER 4 W W 6A W W 7A W W 14A W W 15 W W 17A W W 21 W W 29 W W 35 W W 40 W W 46 W 47 M/AA 48 W 49 M/AA M/AA W 53 M/AA 54 M/AA 55 W 57 Q 58A Q 59 (A, B, C) Q 60 Q 61 Q 62 M/AA 63 (A&B) Q 64 (A&B) Q 65 Q

W = WEEKLY M/AA = MONTHLY AS AVAILABLE Q = QUARTERLY

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 8 Table 2-3 Summaries of the REMP Deviations/Abnormal Events Deviation/Abnormal Actions Taken Event

1. Neutron dosimeter used The Neutron dosimeter used for monitoring location #69 (west for monitoring location #69 site boundary #29) indicated an anomalous reading. The reading had an anomalous reading was considered invalid, the TLD was removed from service and for First Quarter, 2023. the exposure changed to zero. This is documented in CR 23-06382.

2. Environmental holder and On 1/12/2024 it was discovered that site 12 TLD's and the holder both dosimeters used for for the Radiological Environmental Monitoring Program was monitoring location #12 missing from its location. A new 1st Qtr. TLD was placed in its were missing for 4th Quarter, location. CR 24-00356-002 was generated to record this event.

2023 See Table 9-1, Note 2.

3. One of the 2 dosimeters One of the two dosimeters used for monitoring location #1 used for monitoring location indicated an anomalous reading. The dosimeter was inspected 1 was found to be damaged and found to be damaged. The reading is invalid and details following processing. regarding this event can be seen in CR 24-01610. See Table 9-1, Note 1

4. Duplicate sample taken for In addition to Location 48 composite sample (C23-0234), a location 48 for the month of duplicate sample, (C23-0242), was performed. The average of August. the two samples were used in analysis. See Table 8-8, Note 1

5. No Milk Sample for Site Due to a scheduling error, there was no milk sample available for 53 for the month of February the month of February for location 53. Condition Report 23-2023. 05726 includes applicable data for this deviation. See Table 8-7 Note 1

6. Milk Sample for Site 53 Due to an unforeseen error, the counting for this sample stopped did not meet the criteria for prior to sufficient time to meet the LLD for I-131. Reference CR the Lower Limit of Detection 23-05484 for detailed information. See Table 8-7 Note 2.

(LLD).

7. No December Milk No Milk samples were available at the collection time for Samples available for Locations 49 and 53. The CR number associated with this event Locations 49 and 53. is CR 23-05726. See Table 8-7 Note 1.

8. Air Sample Site 17A is On 5/16/2023, it was discovered that the ETM at Air Sample Site valid. ETM Failure #17A stopped working during the sample period 5/9/2023-5/16/2023. The filter paper had normal dust loading; but sample duration time is not known. Sample was calculated by using the sample run time. Sample is valid. CR 23-05482. See Table 8.1, Note 2.

9. Air Sample Site 17A Site 17A ETM was inoperable for weeks 20 and 21. The sample found to have inoperable media did show normal loading and thus considered to be valid.

ETM for weeks 20 and 21. CR 23-05482 was generated to document this deviation. See Table 8-1, Note 2.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 9

10. Air Sample Site 21 A Vein failure for the air sample pump located at Site 21caused considered invalid due to the sample to be invalid for week 25. There appeared to be less vein failure. than normal dust loading and was analyzed for information only.

Sample is invalid. See CR 23-06794 - See Table 8-1, Note 3

11. Air Sample Site 21 found The ETM was found to be inoperable at Site Location 21 for to have inoperable ETM for week 26 (6/20/23 - 6/27/23). The sample media had normal dust week 26. loading and the volume was calculated based on documented run time. CR 23-06793. Sample is valid. See Table 8-1, Note 4.

12. Air Sample Site 21 Degraded air sample flow found for Site Location 21 on 7/5/23 showed degraded sample (week 27). In addition, the ETM malfunctioned and failed to roll-flow and experienced ETM over at max count time. The sample did however appear to have malfunction. normal dust loading on the media and was considered valid.

Reference CR 23-07026. See Table 8-1, Note 5.

13. ETM failed during The ETM failed during the week of 7/5/23 to 7/11/23 for sampling period for week 28 Location 21 (week 28). The sample had normal dust loading and at Site Location 21. determined to be valid based on logged time duration. See CR 23-07640. See Table 8-1, Note 6

14. ETM failed during The ETM failed during the week of 7/11/23 to 7/18/23 for sampling period for week 29 Location 21. The sample had normal dust loading and at Site Location 21. determined to be valid based on logged time duration. See CR 23-07640. See Table 8-1, Note 6

15. Pump failure during The air sample pump at Location 21 for week 49 failed during sampling period for week 49 the week of 11/28/23 to 12/05/23. The sample was considered at Location 21. valid due to normal dust loading. See CR 23-12693. See Table 8-1, Note 7 16.Site 4 has invalid results Air sample pump failure at location 4 caused the results for week due to pump failure for week 50 to be invalid. Reference CR 23-12897. See Table 8-1, Note 8 50.

17. The results for The March 21, 2023, results for Sedimentation Basin #2 were not Sedimentation Basin #2 were valid because of using the incorrect procedure. This resulted in considered invalid. missed LLDs that were not discovered in time to perform a recount. Reference CR 23-04635. See Table 8-10, Note 1

18. The results for WRF The results for WRF Influent for March 21, 2023, were not valid Influent were considered because of using the incorrect procedure. This resulted in missed invalid. LLDs that were not discovered in time to perform a recount.

Reference CR 23-04635. See Table 8-10, Note 1

19. WRF Centrifuge Waste The LLD of 150 pCi/L for Cs-134 was missed. CR 23-07088 Sludge Missed LLD gives detailed information. See Table 8-11, Note 1

20. Duplicate sample taken A duplicate sample was taken for Site 48. Values reported are the for Site 48 Local Residence average of the two samples. See Table 8-6 Drinking Water.

21. No monthly vegetation On 3/1/23 during review of Radiological Environmental samples were collected for Monitoring Program sample analysis, it was identified the Commercial Farm Site #62. monthly analysis of Gamma radioactivity on vegetable samples was missed for February for Commercial Farm Site #62.

Reference CR 23-04847. See Table 8-6, Note 1 PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 10

22. I-131 LLD was not The I-131 LLD for Site 62 was not achieved for Green Romaine.

achieved for Vegetation The Oregano and Green Leaf did meet the LLD, as did the Sample (Green Romaine) for control location. CR 23-07777. See Table 8-10, Note 2 Commercial Farm Site #62.

23. REMP Site 21 Air REMP SITE 21 HAD AN PUMP FAIL FOR WEEK 49B1:B24 -

Sample Pump failure. This Level 8 Enhancement Action Item was created to include the lost sample in the 2023 Annual Environmental Radiological Release Report. On 12/5/2023 it was discovered that site 21 Air pump for REMP sampling failed, due to the Pump failing we did swap the Pump with a new one, the sample is not valid due to this, but we will still test the sample since it does have some dust loading on it. A validation check of the new pump's operation was performed to ensure that the pump or ETM has not failed and a PM schedule for the pumps has been reinstituted with an initial monthly rotation. This CR is for trending purposes only.

Recommend N-0-8, Condition Not Adverse to Quality with a Level 8 AI to Unit 8843 to include the event in the 2023 AREOR. See CR 23-12693-002. See Table 8-2, Note 9

24. REMP Site 4 OOS and to REMP Site 4 Air Monitor Station was found missing. Station be relocated at another site. was removed due to the selling of property. Efforts are underway to finalize the relocation to a location close in proximity to the previous location. CR 24-02928 was written to document the move and provides detailed information regarding the process.

The Air Monitor Station was temporarily located at near the entrance to Maricopa Recycling, which is across 4th St. from the Buckeye Yard (power pole 247486). All samples have been valid.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 11 Figure 2-1 REMP Sample Sites-Map (0-10 miles)

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 12 Figure 2-2 REMP Sample Sites-Map (10-35 Miles)

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 13

3. Sample Collection Program

APS Personnel, using PVNGS procedures, collected all samples.

3.1 Water

Weekly samples were collected from four (4) residence wells for monthly and quarterly composites. Samples were collected in one-gallon containers (plastic cubitainers) and 500 mL glass bottles. The samples were analyzed for gross beta, gamma-emitting radionuclides, and tritium.

Quarterly grab samples were collected from the 45-acre and 85-acre Reservoirs, a c t i v e Evaporation Ponds 1A/B/C, 2A/B, and 3A/B, and onsite wells 27ddc, 34aab, and 27dcb.

Samples were collected in one-gallon containers (plastic cubitainers) and 500 mL glass bottles.

Samples were analyzed for gamma-emitting radionuclides and tritium.

Treated sewage effluent from the City of Phoenix was sampled as a weekly composite at the onsite Water Resources (WR) and analyzed for gamma-emitting radionuclides. A monthly composite was analyzed for tritium.

3.2 Vegetation

Vegetation samples were collected monthly, as available, and were analyzed for gamma-emitting radionuclides.

3.3 Milk

Goat milk samples were collected monthly, as available, and were analyzed for gamma-emitting radionuclides, including low level I-131.

3.4 Air

Air particulate filters and charcoal cartridges were collected at ten (10) sites on a weekly basis. Particulate filters were analyzed for gross beta. Charcoal cartridges were analyzed for Iodine-131. Particulate filters were composited quarterly, by location, and analyzed for gamma-emitting radionuclides.

3.5 Soil, Sludge, and Sediment

Sludge samples were obtained weekly from the WR waste centrifuge (during operational periods) and analyzed for gamma-emitting radionuclides. Cooling tower sludge was analyzed for gamma-emitting radionuclides prior to disposal in the WR sludge landfill.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 14

4. Analytical Procedures

The procedures described in this report are those used by APS to routinely analyze samples.

4.1 Air Particulate

4.1.1 Gross Beta

A glass fiber filter sample is placed in a stainless steel planchet and counted for gross beta activity utilizing a low background gas flow proportional counter.

4.1.2 Gamma Spectroscopy

The glass fiber filters are counted on a multichannel analyzer equipped with a H i g h -

p u r i t y G e r m a n i u m ( HPGe) detector. The resulting spectrum is analyzed by a computer for specific radionuclides and verified by trained technicians.

4.2 Airborne Radioiodine

4.2.1 Gamma Spectroscopy

A charcoal cartridge is counted on a multichannel analyzer equipped with an HPGe detector. The resulting spectrum is analyzed by a computer for Iodine-131.

4.3 Milk

4.3.1 Gamma Spectroscopy

The sample is placed in a plastic Marinelli beaker and counted on a multichannel analyzer equipped with an HPGe detector. The resulting spectrum is analyzed by a computer for specific radionuclides and verified by trained technicians.

4.3.2 Radiochemical I-131 Separation

Iodine in milk sample is reduced with sodium bisulfite and iodine is absorbed by the anion exchange resin. The iodine is eluted with NaOCl. Iodine is extracted from the sample with carbon tetrachloride. The iodine is back extracted from the organic phase with water containing sodium bisulfate and t h e n p r e c i p i t a t e d as C u I. The precipitate is mounted in a planchet and counted for gross beta.

4.4 Vegetation

4.4.1 Gamma Spectroscopy

The sample is pureed in a food processor, placed in a one-liter plastic Marinelli beaker, weighed, and counted on a multichannel analyzer equipped with an HPGe detector. The resulting spectrum is analyzed by a computer for specific radionuclides and verified by trained technicians.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 15 4.5 Sludge/Sediment

4.5.1 Gamma Spectroscopy

The wet/dry sample is placed in a one-liter plastic Marinelli beaker, weighed, and counted on a multichannel analyzer equipped with an HPGe detector. The resulting spectrum is analyzed by a computer for specific radionuclides and verified by trained technicians.

4.6 Water

4.6.1 Gamma Spectroscopy

The sample is placed in a one-liter plastic Marinelli beaker and counted on a multichannel analyzer equipped with a HPGe detector. The resulting spectrum is analyzed by a computer for specific radionuclides and verified by trained technicians.

4.6.2 Tritium

The sample is evaluated to determine the appropriate method of preparation prior to counting. If the sample contains suspended solids or is turbid, it may be filtered, distilled, and/or de-ionized, as appropriate. Eight (8) milliliters of sample are mixed with fifteen (15) milliliters of liquid scintillation cocktail. The mixture is dark adapted and counted for tritium activity using a liquid scintillation counting system.

4.6.3 Gross Beta

A 200-250 milliliter sample is placed in a beaker. Five (5) milliliters of concentrated nitric (HNO3) acid are added and the sample is evaporated down to approximately twenty (20) milliliters. The remaining sample is transferred to a stainless steel planchet.

The sample is heated to dryness and counted for gross beta in a gas flow proportional counter.

4.7 Soil

4.7.1 Gamma Spectroscopy

The samples are sieved, placed in a one-liter plastic Marinelli beaker, and weighed. The samples are then counted on a multichannel analyzer equipped with an HPGe detector.

The resulting spectrum is analyzed by a computer for specific radionuclides and verified by trained technicians.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 16

5. Nuclear Instrumentation

5.1 Gamma Spectrometer

The Canberra Gamma Spectrometer consists of a Canberra System equipped with HPGe detectors, having resolutions of 1.73 keV and 1.88 keV (as determined by full width half max with an energy of 0.5 keV per channel) and respective efficiencies of 21.5% and 38.4% (as determined by the manufacturer with Co-60). The Canberra System is used for all gamma counting. The system uses Canberra developed software to search, identify, and quantify the peaks of interest.

5.2 Liquid Scintillation Spectrometer

A Beckman LS-6500 Liquid Scintillation Counter is used for tritium determinations. The system background averages approximately 12-16 cpm with a counting efficiency of approximately 40% using a quenched standard.

5.3 Gas Flow Proportional Counter

The Tennelec S5E is a low background gas flow proportional counter for gross beta analysis.

The system contains an automatic sample changer capable of counting 50 samples in succession. Average beta background count rate is about 1-2 cpm with a beta efficiency of approximately 30% for Cs-137.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 17

6. Isotopic Detection Limits and Reporting Criteria 6.1 Lower Limits of Detection

The lower limits of detection (LLD) and the method for calculation are specified in the PVNGS ODCM, Reference 4. The ODCM required a priori LLDs are presented in Table 6-1.

6.2 Data Reporting Criteria

Any results that i n d i c a t e a greater than the Minimum Detectable Activity (MDA) (a posteriori LLD) are reported as positive activity with its associated 2 counting error. All results that are less than the MDA are reported as less than values at the associated MDA. For example, if the MDA is 12 pCi/liter, the value is reported as <12.

Typical MDA values are presented in Table 6-3.

Occasionally, the PVNGS ODCM a priori LLDs may not be achieved as a result of:

• Background fluctuations

• Unavoidably small sample sizes

• The presence of interfering radionuclides

• Self-absorption corrections

• Decay corrections for short half-life radionuclides

• Other uncontrollable circumstances

In these instances, the contributing factors will be noted in the table where the data are presented. A summary of deviations/abnormal events is presented in Table 2-3 and includes a description of any sample results that did not meet a priori LLD requirements.

6.3 LLD and Reporting Criteria Overview

Making a reasonable estimate of the limits of detection for a counting procedure or a radiochemical method is usually complicated by the presence of significant background. It must be considered that the background or blank is not a fixed value but that a series of replicates would be normally distributed. The desired net activity is the difference between the gross and background activity distributions. The interpretation of this difference becomes a problem if the two di st ri but i ons intersect as indicated in the diagram.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 18 If sufficient replicate analyses are run, it is expected that the results would fall in a normal Ga us s i a n d i s t r i b u t i o n. Standard statistics allow a n e s t i m a t e of t h e p r o b a b i l i t y of a n y deviation from the mean value. It is common practice to report the mean +/- one or two standard deviations as the result. In routine analysis, such replication is not carried out, and it is not possible to report a Gaussian standard deviation. With counting procedures, however, it is possible to estimate a Poisson standard deviation directly from the count. Data are commonly reported as the measured value +/- one or two Poisson standard deviations. The reported values are then considered to give an indication of the range in which the true value might be expected to occur.

LLD is the smallest amount of sample activity that will yield a net count for which there is confidence at a p r e d e t e r m i n e d level t h a t a c t i v i t y is p r e s e n t. LLDs a r e c a l c u l a t e d values f o r individual radionuclides based on several different factors including sample size, counting efficiency and background count rate of the instrument, the background and sample counting time, the decay time, and the chemical recovery of the analytical procedures. A minimum detectable activity value (MDA) is the smallest amount of activity that can be detected in an actual sample and uses the values obtained from the instrument and outcome of the analytical process. Therefore, the MDA values may differ from the calculated LLD values if the sample size and chemical recovery, decay values, or the instrument efficiency, background, or count time differed from those used in the LLD calculation.

The factors governing the calculation of the LLD and MDA values are discussed below:

1. Sample Size: The number of observations included in a statistical analysis.

Sample size dictates the amount of information available about a studied subject to make accurate inferences.

2. Counting Efficiency: The fundamental quantity in the measurement of a radioactive substance is the number of disintegrations per unit time. As with most physical measurements in analytical chemistry, an absolute measurement of the disintegration rate is seldom possible, rather it is necessary to compare the sample with one or more standards. The standards determine the counter efficiency that may then be used to convert sample counts per minute (cpm) to disintegrations per minute (dpm).

3. Background Count Rate: Any counter will show a certain counting rate without a sample in position. This background counting rate comes from several sources: 1) natural environmental radiation from the surrounding materials, 2) cosmic radiation, and 3) the natural radioactivity in the counter material itself. The background counting rate will depend on the amounts of these types of radiation and the sensitivity of the counter to the radiation.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 19

4. Background and Sample Counting Time: The amount of time devoted to the counting of the background depends on the level of activity being measured. In general, with low level samples, this time should be about equal to that devoted to counting a sample.

5. Time Interval between Sample Collection and Counting: Decay measurements are useful in identifying certain short-lived nuclides. The disintegration constant is one of the basic characteristics of a specific radionuclide and is readily determined if the half-life is s u f f i c i e n t l y short.

To ensure the required LLDs are achieved, appropriate decay correction values are used to account for radioactive decay during transit time and sample processing.

Table 6-1 ODCM Required Lower Limits of Detection (a priori)

• If no drinking water pathway exists, a value of 3000 pCi/liter may be used

• • If no drinking water pathway exists, a value of 15 pCi/liter may be used

NOTES:

This list does not mean that only these nuclides are to be detected and reported. Other peaks that are measurable and identifiable, together with the above nuclides, shall also be identified and reported.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 20 Table 6-2 ODCM Required Reporting Levels

• For drinking water samples. This is a 40 CFR 141 value. If no drinking water pathway exists, a value of 30,000 pCi/L may be used.

• • If no drinking water pathway exists, a reporting level of 20 pCi/L may be used.

Table 6-3 Typical MDA Values Analysis/Nuclide Water Milk Airborne Particulate Vegetation (pCi/liter) (pCi/liter) or Gas (pCi/m3) (pCi/kg, wet)

Gross Beta 2.08 0.004 H-3 326 Mn-54 10 Fe-59 20 Co-58 9 Co-60 11 Zn-65 22 Zr-95 16 Nb-95 10 I-131 10a 1 0.04b 49 Cs-134 9 1 0.003b 47 Cs-137 10 1 0.003b 61 Ba-140 33 3 La-140 13 1 NOTES:

a - low level I-131 is not required since there is no drinking water pathway b - Based on 433 m3, the normal weekly sample volume

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 21

7. Interlaboratory Comparison Program 7.1 Quality Control Program

APS maintains an extensive QA/QC Program to provide assurance that samples are collected, handled, tracked, and analyzed to specified requirements. This program includes appropriate elements of USNRC Regulatory Guide 4.15, Quality Assurance for Radiological Monitoring Programs (Normal Operations) - Effluent Streams and the Environment, Revision 1. The program includes procedures for sample collection preparation and tracking, sample analysis, equipment calibration and checks, and ongoing participation in an interlaboratory comparison program. Duplicate/replicate samples are analyzed to verify analytical precision and sample methodology. Comprehensive data reviews are performed including trending of data where appropriate.

During 2023, APS analyzed the following sample types under the interlaboratory comparison program:

• Beta/Gamma/ in Air Filter

• I-131 in Air

• Beta in Water

• Gamma in Water

• Tritium in Water

• Gamma in Milk

7.2 Intercomparison Results

APS participates in a crosscheck program using vendor supplied blind radionuclide samples. Results for the interlaboratory comparison program are presented in Table 7-1

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 22 Table 7-1 Interlaboratory Comparison Results 2023 Eckert & Ziegler Analytics Environme nta l Cross Check Re sults

Sample Analysis 1 sigma Known NRC Type Type Nuclide PV N GS ValueE rror Value Re solution* Ratio AcceptableRange?

E1883 Ga mma DET1 Water Ce-141 8.26E+01 9.69E+00 8.25E+01 9 1.00 0.60 - 1.66 YES Co-58 9.29E+019.85E+009.47E+01 9 0.98 0.60- 1.66 YES Co-60 2.47E+02 1.61E+01 2.52E+02 15 0.98 0.60 - 1.66 YES Cr-51 1.87E+02 3.71E+01 2.01E+02 5 0.93 0.50 - 2.00 YES Cs-134 1.18E+02 8.04E+00 1.26E+02 15 0.94 0.60 - 1.66 YES Cs-137 1.52E+02 1.48E+01 1.58E+02 10 0.96 0.60 - 1.66 YES Fe-59 1.20E+02 1.14E+01 1.18E+02 11 1.02 0.60 - 1.66 YES Mn-54 1.19E+02 1.19E+01 1.12E+02 10 1.06 0.60 - 1.66 YES Zn-65 1.81E+02 1.80E+01 1.70E+02 10 1.06 0.60 - 1.66 YES I-131 6.27E+01 9.72E+00 5.57E+01 6 1.13 0.50 - 2.00 YES E13883 Ga mma DET2 Water Ce-141 8.17E+01 8.91E+00 8.25E+01 9 0.99 0.60 - 1.66 YES Co-58 9.36E+019.54E+009.47E+01 10 0.99 0.60- 1.66 YES Co-60 2.45E+02 1.48E+01 2.52E+02 17 0.97 0.75 - 1.33 YES Cr-51 1.96E+02 3.58E+01 2.01E+02 5 0.98 0.50 - 2.00 YES Cs-134 1.14E+02 7.91E+00 1.26E+02 14 0.90 0.60 - 1.66 YES Cs-137 1.58E+02 1.57E+01 1.58E+02 10 1.00 0.60 - 1.66 YES Fe-59 1.29E+02 1.10E+01 1.18E+02 12 1.09 0.60 - 1.66 YES Mn-54 1.16E+02 1.12E+01 1.12E+02 10 1.04 0.60 - 1.66 YES Zn-65 1.74E+02 1.63E+01 1.70E+02 11 1.02 0.60 - 1.66 YES I-131 5.71E+01 1.06E+01 5.57E+01 5 1.03 0.50 - 2.00 YES E13886 Ga mma DET1 Filter Ce-141 7.82E+01 9.13E+00 7.86E+01 9 0.99 0.60 - 1.66 YES Co-58 8.94E+01 1.22E+01 8.82E+01 7 1.01 0.50 - 2.00 YES Co-60 2.45E+02 2.45E+02 2.35E+02 1 1.04 0.40 - 2.50 YES Cr-51 2.08E+02 4.62E+01 1.87E+02 5 1.11 0.50 - 2.00 YES Cs-134 1.10E+02 8.95E+00 1.17E+02 12 0.94 0.60 - 1.66 YES Cs-137 1.57E+02 2.15E+01 1.47E+02 7 1.07 0.50 - 2.00 YES Fe-59 1.20E+02 1.44E+01 1.10E+02 8 1.09 0.60 - 1.66 YES Mn-54 1.09E+02 1.36E+01 1.04E+02 8 1.05 0.60 - 1.66 YES Zn-65 1.77E+02 2.47E+01 1.59E+02 7 1.11 0.50 - 2.00 YES E13886 Ga mma DET2 Filter Ce-141 8.26E+01 9.51E+00 7.68E+01 9 1.08 0.60 - 1.66 YES Co-58 1.00E+02 1.26E+01 8.82E+01 8 1.13 0.60 - 1.66 YES Co-60 2.34E+02 1.53E+01 2.35E+02 15 1.00 0.60 - 1.66 YES Cr-51 1.90E+02 3.56E+01 1.87E+02 5 1.02 0.50 - 2.00 YES Cs-134 9.87E+01 7.33E+00 1.17E+02 13 0.84 0.60 - 1.66 YES Cs-137 1.60E+02 2.08E+01 1.47E+02 8 1.09 0.60 - 1.66 YES Fe-59 1.29E+02 1.32E+01 1.10E+02 10 1.17 0.60 - 1.66 YES Mn-54 1.21E+02 1.04E+00 1.04E+02 116 1.16 0.80 - 1.25 YES Zn-65 1.98E+02 2.27E+01 1.59E+02 9 1.25 0.60 - 1.66 YES E13885 I-131 DET1 Cartridge I-131 6.52E+01 8.98E+00 6.66E+01 7 0.98 0.50 - 2.00 YES E13885 I-131 DET2 Cartridge I-131 6.72E+01 6.12E+00 6.66E+01 11 1.01 0.60 - 1.66 YES E13884A Gross Beta Air g beta 8.76E+01 2.01E+00 8.85E+01 44 0.99 0.75 - 1.33 YES E13887 Gamma DET 1 Milk I-131 3.96E+01 2.76E+00 3.99E+01 14 0.99 0.60 - 1.66 YES Ce-141 1.20E+01 2.20E+00 1.19E+01 5 1.01 0.50 - 2.00 YES Co-58 1.34E+01 1.63E+00 1.37E+01 8 0.98 0.60 - 1.66 YES Co-60 3.32E+01 2.26E+00 3.65E+01 15 0.91 0.60 - 1.66 YES Cr-51 3.05E+01 9.35E+00 2.91E+01 3 1.05 0.40 - 2.50 YES Cs-134 1.72E+01 1.14E+00 1.82E+01 15 0.95 0.60 - 1.66 YES Cs-137 2.10E+01 2.28E+00 2.29E+01 9 0.92 0.60 - 1.66 YES Fe-59 1.64E+01 1.96E+00 1.71E+01 8 0.96 0.60 - 1.66 YES Mn-54 1.67E+01 1.76E+00 1.62E+01 9 1.03 0.60 - 1.66 YES Zn-65 2.63E+01 2.76E+00 2.47E+01 10 1.06 0.60 - 1.66 YES E13887 Gamma DET 2 Milk I-131 3.82E+01 3.72E+00 3.99E+01 10 0.96 0.60 - 1.66 YES Ce-141 1.15E+01 2.00E+00 1.19E+01 6 0.97 0.50 - 2.00 YES Co-58 1.28E+01 1.59E+00 1.37E+01 8 0.93 0.60 - 1.66 YES Co-60 3.52E+01 2.28E+00 3.65E+01 15 0.96 0.60 - 1.66 YES Cr-51 3.43E+01 1.11E+01 1.82E+01 3 1.88 0.40 - 2.50 YES Cs-134 1.59E+01 1.00E+00 1.82E+01 16 0.87 0.75 - 1.33 YES Cs-137 2.26E+01 2.71E+00 2.29E+01 8 0.99 0.60 - 1.66 YES Fe-59 1.66E+01 2.14E+00 1.71E+01 8 0.97 0.60 - 1.66 YES Mn-54 1.65E+01 1.54E+00 1.62E+01 11 1.02 0.60 - 1.66 YES Zn-65 2.55E+01 2.28E+00 2.47E+01 11 1.03 0.60 - 1.66 YES

E13888 Gross Beta Water g beta 2.23E+02 3.44E+00 2.05E+02 65 1.09 0.80 - 1.25 YES

E13889 H-3 Water H-3 1.09E+04 3.44E+02 1.21E+04 32 0.90 0.75 - 1.33 YES

• calculated from PVNGS value/1 sigma error value

NRC Acceptance Criteria 1 Re sol uti on Ra ti o

<4 0.4-2.5 4-7 0.5-2.0 8-15 0.6-1.66 16-50 0.75-1.33 51-200 0.80-1.25

>200 0.85-1.18

1 From C Y -NISP-201, Rev1, A ttachm ent E

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 23

8. Data Interpretation and Conclusions

Associated with the analytical process are potential random and systematic errors. Systematic errors can be caused by instrument malfunctions, incomplete precipitation, back scattering, and self-absorption.

Efforts are made to minimize both systematic and random errors in the data reported. Systematic errors are minimized by performing reviews throughout the year. For example, instruments are checked routinely with radioactive sources, and recovery and self-absorption factors based on individual sample analyses are incorporated into the calculation equations where necessary. Random errors are reduced by comparing all data to historical data for the same site and performing comparisons between analytical results when available. In addition, when data appears to not match historical results, analyses may be rerun on a separate aliquot of the sample to verify the presence of the activity. The acceptance of data is dependent upon the results of quality control samples and is part of the data review process for all analytical results.

The "plus or minus value" reported with each analytical result represents the counting error associated with the result and gives the 95% confidence (2 ) interval around the data.

Most samples contain radioactivity associated with natural background/cosmic radioactivity (i.e., K-40, Th-234, Be-7). Gross beta results for drinking water and air are due to natural background. Gamma-emitting radionuclides, which can be attributed to natural background sources, are not indicated in this report.

Results and interpretation of the data for samples analyzed during 2023 are presented in the following sections.

8.1 Air Particulates

Weekly gross beta results, in quarterly format, are presented in Table 8-1and Table 8-2. Gross beta activity at indicator locations ranged from 0.006 to 0.083 pCi/m3. Mean quarterly activity is normally calculated using weekly activity over a thirteen (13) week period. Also presented in the tables are the weekly mean values of all the sites as well as the percent relative standard deviation (RSD %) for the data.

Table 8-3 displays the results of gamma spectroscopy on the quarterly composites of the weekly samples. No plant-related activity was identified.

8.2 Airborne Radioiodine

Table 8-4 and Table 8-5Error! Reference source not found. present the quarterly radioiodine results.

Radioiodine was not observed in any samples.

8.3 Vegetation

Table 8-6 presents gamma isotopic data for the vegetation samples. One of three vegetation samples from Site 62 in April 2023 did not meet the required LLD of 60 pCi/kg. An MDA of 62 pCi/kg was achieved. The remaining two samples met the required LLD. Due to the short-lived half-life of I-131 of approximately 8 days, a recount would likely have not met the required LLD.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 24 8.4 Milk

Table 8-7 presents gamma isotopic data for the goat milk samples. No gamma-emitting radionuclides were observed in any of the samples.

8.5 Drinking Water

Samples were analyzed for gross beta, tritium, and gamma-emitting radionuclides. Results of these analyses are presented in Table 8-8. No tritium or gamma-emitting radionuclides were detected in any samples. Gross beta activity ranged from less than detectable to a high of 8.44 pCi/liter. The gross beta activity is attributable to natural (background) radioactive materials.

8.6 Groundwater

Groundwater samples were analyzed from three onsite wells (regional aquifer) for tritium and gamma-emitting radionuclides. Results obtained from the analysis of the samples are presented in Table 8-9.

No tritium or gamma-emitting radionuclides were observed in any of the samples.

8.7 Surface Water

Surface water samples from the Reservoirs and Evaporation Ponds were analyzed for tritium and gamma-emitting radionuclides. The two Reservoirs contain processed sewage water from the City of Phoenix and are approximately 45 and 85 acres in size. The three Evaporation Ponds receive mostly circulating water from main turbine condenser cooling and are about 200-250 acres each.

Sample results are presented in Table 8-10. I-131 is sometimes observed in Reservoirs and Evaporation Ponds, which is the result of radiopharmaceutical I-131 in the Phoenix sewage effluent and is not attributable to plant effluents. Except for WRF Influent, I-131 was not observed in these surface water samples during 2023.

Tritium was routinely observed in the Evaporation Ponds. The highest concentration was 1059 pCi/liter. Tritium was not detected in the Reservoirs. The tritium identified in the Evaporation Ponds has been attributed to permitted plant gaseous effluent releases and secondary plant liquid discharges (i.e., condensate overboard discharge, secondary side steam generator drains, secondary plant sumps, demineralizer regeneration waste).

The tritium concentrations were compared to historical values and are considered typical for the Evaporation Ponds. Evaporation Pond 3A has been drained for liner repairs and has not received any influent from the plant since 2016; therefore, no sample was obtained.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 25 8.8 Sludge and Sediment

8.8.1 Water Resources Centrifuge Waste Sludge

Sludge samples were obtained from the Water Resources (WR) centrifuge and analyzed by gamma spectroscopy. I-131 activity in the sludge is consistent with historical values and, as previously discussed, is due to radiopharmaceuticals in the WR Influent. The concentration of I-131 ranged from no detectable to 1370 pCi/kg.

Results for WR centrifuge waste sludge can be found in Table 8-11.

8.8.2 Cooling Tower Sludge

Sludge/sediment originating from the Unit 1 and Unit 2 Cooling Towers and Circulating Water canals was disposed of in the WR sludge landfill during 2023. Sample results can be found in Table 8-11.

8.9 Data Trends

Figure 8-1 through Figure 8-8 present data in graphical format. Historical data are displayed for comparison where practical. All data are consistent with historical values.

8.10 Hard-To-Detect Radionuclide Results

Table 8-12 shows the results of the three subsurface samples obtained from 3 tritium monitoring points. These samples were analyzed for hard-to-detect radionuclides (i.e., C-14, Fe-55, Ni-63, Sr-90) and all results were

<MDA. These results indicate that no leaks from plant systems have affected groundwater.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 26

Table 8-6 Vegetation V E GE TA TI O N ODCM required sampl e s de noted by

• uni ts ar e pCi /kg, wet

DATE L O C A TI O N TY P ECOLLECTED I-131 Cs-134 Cs-137 Note

• • January-No Sample Available**

• • February-No Sample Aquired** 1

• • March-No Sample Available**

• • April-No Sample Available**

LOCAL **May-No Sample Available**

RESIDENCE **J une-No Sample Available**

(Site #47)* **J uly-No Sample Available**

• • August-No Sample Available**

• • September-No Sample Available**

• • October-No Sample Available**

• • November-No Sample Available**

• • December-No Sample Available**

Arugula 19-Jan-23 <3 0 <3 3 <4 1 Ba b y Sp i na c h 19-Jan-23 <18 <29 <42 Baby Spinach 19-Jan-23 <3 8 <3 2 <4 9

• • February-No Sample Aquired** 1 Baby Spinach 23-Mar-23 <35 <44 <31 Re d Ro ma i ne 23-Mar-23 <35 <29 <45 Green Romaine 23-Mar-23 <3 9 <3 3 <5 3 Green Romaine 20-Apr-23 <6 2 <4 1 <4 0 2 Red Leaf 20-Apr-23 <4 1 <4 0 <4 6 Red Leaf 20-Apr-23 <39 <44 <37 CO M M ERCIAL Baby Red Leaf 18-May-23 <48 <49 <61 FARM Oregano 18-May-23 <5 4 <5 8 <5 5 (Site #62)* Green Leaf 18-May-23 <46 <48 <15

• • J une-No Sample Available**

• • J uly-No Sample Available**

• • Aug-No Sample Available**

• • September-No Sample Available**

Spinach 19-Oct-23 <54 <44 <70 Baby Green Romaine 19-Oct-23 <45 <56 <59 Green Romaine 15-Nov-23 <56 <58 <76 Baby Red Leaf 15-Nov-23 <5 9 <1 8 <6 8 Red Romaine 15-Nov-23 <5 2 <5 6 <6 3

Baby Green Oak Leaf 21-Dec-23 <5 3 <4 6 <1 5 Baby Red Romaine 21-Dec-23 <4 9 <5 0 <1 6 Baby Spinach 21-Dec-23 <57 <16 <73

• • January-No Sample Available**

• • February-No Sample Aquired** 1

• • March-No Sample Available**

• • April-No Sample Available**

• • May-No Sample Available**

LOCAL *

• J u me - N o S a mp l e A v a i l a b l e *

• RESIDENCE **J uly-No Sample Available**

(Site #49) * **Aug-No Sample Available**

• • October-No Sample Available**

• • November-No Sample Available**

• • December-No Sample Available**

Note 1: Monthl y Ve ge ta ti on sa mpl e s w e r e not c ol l e cte d due to s che dul i ng e r r or. A r e vi ew of the a i r sample data revelas no abnormal results, confirming that no impact to the environment was missed during thi s s a mpling period. CR 23-04847 Note 2: LLD for Site 62 was not achived for I-131. Required LLD is 60 pCi/kg; achieved MDA is 62 pCi/kg. CR: 23-07777

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 32 Table 8-7 Milk MI L K ODCM required s amples de noted by

• units are pCi/liter SAMP L E DAT E LOCATION COLLECTED I-131 Cs-134 Cs-137 Ba-140 La-140 Note 19-J a n-23 <1 <1 <1 <3 <1

• • February-No Sample Collected** 1 23-Mar-23 <1 <1 <1 <3 <1 Local Resident 20-Apr-23 <4 <3 <4 <11 <3 2 Goats 18-Ma y-23 <1 <1 <1 <3 <1 (Site #53)* 22-J un-23 <1 <1 <1 <3 <1 20-J ul-23 <1 <1 <1 <3 <1 17-A ug-23 <1 <1 <1 <4 <1 21-Se p-23 <1 <1 <1 <4 <1 19-O c t-23 <1 <1 <1 <3 <1 08-N ov-23 <1 <1 <1 <4 <1

• • December-No Sample Available**

13-J a n-23 <1 <1 <1 <3 <1 Local Resident 17-Fe b-23 <1 <1 <1 <3 <1 Goats 16-Mar-23 <1 <1 <1 <3 <1 (Site #54)* 13-A pr-23 <1 <1 <1 <3 <1 11-Ma y-23 <1 <1 <1 <3 <1 15-J un-23 <1 <1 <1 <3 <1 13-J ul-23 <1 <1 <1 <3 <1 10-A ug-23 <1 <1 <1 <4 <1 14-Se p-23 <1 <1 <1 <4 <1 12-O c t-23 <1 <1 <1 <4 <1 08-N ov-23 <1 <1 <1 <3 <1 19-D e c -23 <1 <1 <1 <3 <1

• • January-No Sample Available**

• • February-No Sample Available**

• • March-No Sample Available**

• • April-No Sample Available**

• • May-No Sample Available**

LOCAL **June-No Sample Available**

RESIDENCE **July-No Sample Available**

(Site #49) * **August-No Sample Available**

• • September-No Sample Available**

• • October-No Sample Available**

• • November-No Sample Available**

• • December-No Sample Available**

Note 1: Due to scheduling error, February Milk sampls were not collected. CR 23-05726 Note 2: APEX softw are stopped analysis prior to meeting desired LLD for I-131. CR 23-05484

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 33

Table 8-10 Surface Water

SURFACE WATER ODCM required samples denoted by

• units are pCi/liter SAMPLE DATE LOCATION COLLECTED Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 Tritium Notes 45 ACRE 31-Jan-23 <11 <12 <23 <11 <20 <10 <12 <12 <7 <5 <27 <12 <353 RE SE RVOI R 25-Apr-23 <8 <9 <20 <11 <24 <8 <15 <9 <9 <10 <34 <9 <380 (Site #61)

• 25-Jul-23 <10 <11 <22 <11 <20 <10 <14 <11 <10 <8 <35 <11 <333 31-Oct-23 <7 <9 <12 <11 <19 <9 <15 <11 <9 <8 <31 <9 <361 8 5 AC RE 31-Jan-23 <10 <10 <15 <10 <17 <9 <16 <12 <8 <10 <34 <10 <362 RE SE RVOI R 25-Apr-23 <12 <9 <18 <13 <23 <9 <16 <9 <8 <11 <34 <9 <386 (Site #60)

• 25-Jul-23 <8 <8 <14 <8 <23 <8 <11 <11 <8 <11 <29 <8 <327 31-Oct-23 <11 <10 <20 <10 <21 <7 <18 <10 <9 <11 <38 <10 <326 1 EVAP POND 1 31-Jan-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE (Site #59) *CELL 25-Apr-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 1A 25-Jul-23 <11 <9 <18 <11 <24 <9 <17 <11 <9 <11 <33 <8 466+/-202 31-Oct-23 <11 <11 <21 <13 <25 <9 <19 <9 <9 <11 <36 <13 411+/-223 31-Jan-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE CELL 1B 25-Apr-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 25-Jul-23 <10 <9 <19 <9 <20 <9 <18 <11 <8 <10 <31 <8 807+/-210 31-Oct-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 31-Jan-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE CELL 1C 25-Apr-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 25-Jul-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 31-Oct-23 <12 <10 <26 <12 <28 <11 <18 <10 <9 <14 <37 <8 <360 EVAP POND 2 31-Jan-23 <9 <9 <19 <9 <19 <11 <19 <9 <8 <11 <34 <8 811+/-219 (Site #63) *CELL 25-Apr-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 2A 25-Jul-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 31-Oct-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 31-Jan-23 <10 <10 <19 <10 <21 <10 <18 <9 <8 <10 <32 <7 1059+/-224 CELL 2B 25-Apr-23 <10 <11 <21 <14 <23 <10 <20 <10 <8 <8 <32 <9 <380 25-Jul-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE 31-Oct-23 NO SAMPLE REQUIRED-NO INFLUENT SINCE LAST SAMPLE EVAP POND 3 31-Jan-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT (Site #64) *CELL 25-Apr-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT 3A 25-Jul-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT 31-Oct-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT 31-Jan-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT CELL 3B 25-Apr-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT 25-Jul-23 NO SAMPLE REQUIREED-POND IS DRAINED FOR REPAIRS AND HAS NO INFLUENT 31-Oct-23 <10 <13 <23 <10 <24 <11 <16 <10 <10 <12 <35 <10 <352

1 Resampled due to an unidentifiable peak and positive H3 - See Analysis Report C23-0316

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 37

Table 8-11 Sludge/Sediment S L UDGE / S E DIME NT O DCM r equi r ed sampl es denote d by

• units are pCi/kg, wet SAM P LE DATE LOCATION COLLECTED I-131 Cs-134 Cs-137 In-111 Notes 2-Jan-23 <66 <144 10-Jan-23 <124 <141 17-Jan-23 <122 <128 24-Jan-23 767+/-213 <130 <111 31-Jan-23 498+/-158 <152 <149 1 7-Feb-23 1370+/-279 <136 <127 13-Feb-23 751+/-189 <101 <107 21-Feb-23 920+/-255 <34 <145 28-Feb-23 557+/-190 <132 <133 7-Mar-23 <71 <143 14-Mar-23 487+/-162 <75 <135 WR F 21-Mar-23 1300+/-294 <54 <159 CENTRIF UGE 28-Mar-23 594+/-195 <125 <109 WASTE SLUDGE 4-Apr-23 643+/-191 <70 <110 11-Apr-23 <103 <136 18-Apr-23 **WR Outage-No Sample Available**

25-Apr-23 **WR Outage-No Sample Available**

2-May-23 **WR Outage-No Sample Available**

9-May-23 526+/-187 <114 <153 16-May-23 <34 <168 23-May-23 523+/-201 <137 <151 30-May-23 785+/-172 <76 <94 6-Jun-23 405+/-123 <85 <73 13-Jun-23 376+/-40 <14 <16 25+/-10 20-Jun-23 329+/-166 <129 <46 27-Jun-23 916+/-241 <119 <131 5-Jul-23 862+/-214 <130 <113 11-Jul-23 <28 <95 18-Jul-23 <106 <172 25-Jul-23 561+/-182 <137 <103 1-Aug-23 970+/-197 <86 <72 8-Aug-23 <87 <85 15-Aug-23 <130 <159 22-Aug-23 <135 <143 29-Aug-23 < 88 < 136 5-Sep-23 <113 <152 12-Sep-23 <29 <141 WR F 19-Sep-23 <83 <105 CENTRIF UGE 26-Sep-23 338+/-133 <37 <174 WASTE SLUDGE 3-Oct-23 <137 <137 10-Oct-23 <94 <116 17-Oct-23 **WR Outage-No Sample Available**

24-Oct-23 **WR Outage-No Sample Available**

31-Oct-23 **WR Outage-No Sample Available**

7-Nov-23 340+/-124 <85 <84 14-Nov-23 <106 <80 21-Nov-23 154+/-90 <36 <150 28-Nov-23 295+/-107 <84 <91 5-Dec-23 <99 <84 12-Dec-23 353+/-127 <81 <145 19-Dec-23 305+/-121 <79 <114 26-Dec-23 574+/-193 <145 <178 Note 1: Missed Cs-134 LLD of 150 pCi/L; MDA of 152 pCi/L achieved. CR 23-07088

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 42 Table 8-11 Sludge/Sediment (Continued)

Cooling Tower Sludge

Unit Cycle Approximate Isotope Activity Range Sample Type Volume (yd3) (pCi/g)

U3R23 582 All principal gamma-emitters <MDA Towers/Canal Sludge U2R24 273 All principal gamma-emitters <MDA Towers/Canal Sludge

Table 8-12 Hard -To-Detect Radionuclide Results

Hard-To-Detect Radionuclide (pCi/Liter)

Sample Location Well number Sample Date C-14 Fe-55 Ni-63 Sr-90 Unit 1 (outside RCA) APP-12 11/14/2023 <70.6 <21.1 <3.99 <1.90 Unit 2 (inside RCA) H0A 9/16/2023 <84.1 <21.1 <3.83 <1.74 Unit 3 (inside RCA) H11 9/15/2023 <1.93 <19.6 <4.44 <1.93

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 43 Figure 8-1 Gross Beta in Air, 1st-2nd Quarters

Figure 8-2 Gross Beta in Air, 3rd-4th Quarters

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 44 Figure 8-3 Historical Gross Beta in Air (Weekly System Average)

Figure 8-4 Historical Gross Beta in Air (Annual Site to Site Comparisons) Compared to Pre-Op Note: 7A is not included due to the location change since pre-operational period.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 45 Figure 8-5 Gross Beta in Drinking Water Notes: MDA values are plotted as activity (i.e., <2.3 is plotted as 2.3). The action level is 30 pCi/liter.

Figure 8-6 Evaporation Pond Tritium Activity (Pre-Op-2008)

Note: Zero values represent no sample taken for sampling period, per procedural guidance or lack of sample material.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 46 Figure 8-7 Evaporation Pond Tritium Activity (2017-2023)

Note: Zero values represent no sample taken for sampling period, per procedural guidance or lack of sample material.

Figure 8-8 Sedimentation Basin 2 Cs-137

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 47

9. Thermoluminescent Dosimeter (TLD) Results and Data

The environmental TLD used at PVNGS is the Panasonic Model 812 Dosimeter. The Model 812 is a multi-element dosimeter combining two elements of lithium borate and two elements of calcium sulfate under various filters.

TLDs were placed in fifty locations from one to thirty-five miles from the PVNGS. TLD locations are shown in Figure 2-1 and Figure 2-2 and are described in Table 9-1. TLD results for 2023 are presented in Table 9-2. D e f i n i t i o n s f o r Table 9-2 a r e a s f o l l o w s :

MDDQ: Minimum differential dose, quarterly, 3 times 90th percentile sQ determined from analysis (mRem).

MDDA: Minimum differential dose, annual, 3 times 90th percentile sA determined from analysis (mRem).

BQ: Quarterly baseline (mRem) (average of previous 5 years)

MQ: Locations 91-day standard quarter normalized dose (mRem per standard quarter)

LQ: Quarterly investigation level dose (mRem)

BA: Baseline background dose (mRem) (annual)

MA: Annual monitoring data - MA determined by normalizing available quarterly data to 4 full quarters

LA: Annual investigation level dose (mRem)

ND: Non-Detectable

The baseline is calculated as the average of the previous 5-year measurements. The minimum differential dose (MDD) is calculated as 3 times the 90th percentile standard deviation of the data from the previous 5 years; quarterly MDD is calculated using the quarterly data and annual MDD is calculated using the annual summation of the quarterly data. Investigation level is calculated by the difference of the data measurement and the baseline; results less than, or equal to the MDD are Non-Detectable (ND) and any result exceeding the MDD meets the threshold for the investigation level.

Locations exceeding the investigation level will be evaluated for cause and impact to the public and environment.

Historical environmental gamma radiation results for 1985 through 2023 are presented in graphical form on Figure 9-1 (excluding transit control TLD #45). Figure 9-2 depicts the environmental TLD results from 2023 as compared to the pre-operational TLD results (excluding sites #41 and #43, as they were deleted and later assigned to a new location, and #46-50, as they had no pre-op TLD at the location for comparison). The site-to-site comparisons indicate a direct correlation with respect to pre-operational results. It is indicated that the offsite dose, as measured by TLDs, has not changed since Palo Verde became operational.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 48 Table 9-1 TLD Site Locations (Distance and direction are relative to Unit 2 in miles)

• Site #6 and site #44 are the control locations.

• • Site #45 is the transit control TLD (stored in lead pig).

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 49 Table 9-2 Environmental TLD Results 2023 Annual Environmental TLD Monitoring Report Palo Verde 2021 MDDQ: 5 mrem Palo V erde 2021 MDDA: 10 mrem

Quarterly (mrem) Annual (mrem)

Location Description BQ MQQ1 MQQ2 MQQ3 MQQ4 LQQ1 LQQ2 LQQ3 LQQ4 BA MA LA 1 APS Western Division Office, Goodyear 24.5 25.4 26.0 25.6 28.4 N D N D N D N D 98.0 105.4 N D 1 2 Scott-Libby School, Perryville a nd Perryville Roa ds 21.5 21.5 22.3 22.0 19.6 N D N D N D N D 85.9 85.5 N D 3 Liberty School, 19800 West Hi ghwa y 85 23.1 24.8 23.8 25.4 21.5 N D N D N D N D 92.3 95.5 N D 4 APS Buckeye Office, 615 N orth 4th Street, Buckeye 23.9 24.5 24.6 24.9 24.8 N D N D N D N D 95.7 98.8 N D 5 Pa l o Verde School, 291st Ave a nd Old US 80 19.6 20.6 19.6 20.7 19.4 N D N D N D N D 78.2 80.3 N D 6 APS Gila Bend Substa tion, Service Roa d west of town off I-8 25.7 27.1 26.4 28.3 25.2 N D N D N D N D 102.6 107.0 N D 7 N ortheast corner of Old US 80 and Arlington School Road 25.2 25.5 24.9 25.8 24.2 N D N D N D N D 100.6 100.4 N D 8 Southern Pa cific Pipeline Roa d, 1.4 miles SW of 355th Ave 23.6 25.4 24.4 24.3 24.0 N D N D N D N D 94.5 98.2 N D 9 Southern Pa cific Pipeline Roa d, 2.5 miles SW of 355th Ave 27.7 28.9 27.8 29.8 27.4 N D N D N D N D 110.9 113.8 N D 10 Southeast corner of 355th Ave and Elliot Road 23.5 24.7 24.1 24.4 22.3 N D N D N D N D 94.0 95.5 N D 11 N orthwest corner of 339th Ave a nd Dobbins Roa d 24.5 24.7 24.4 24.9 24.5 N D N D N D N D 97.8 98.4 N D 12 N ortheast corner of 339th Ave and Buckeye-Salome Road 23.5 23.4 24.1 25.1 N D N D N D 94.2 96.8 N D 2 13 N orth site bounda ry 24.9 25.7 25.5 27.1 25.6 N D N D N D N D 99.6 103.8 N D 14 North Northeast site boundary 24.7 25.1 24.9 26.4 22.1 N D N D N D N D 98.6 98.5 N D 15 N ortheast si te boundary, on WRF access roa d 23.6 23.9 23.0 25.6 22.1 N D N D N D N D 94.6 94.6 N D 16 Ea st N orthea st site bounda ry 23.2 24.5 23.6 24.5 22.2 N D N D N D N D 92.9 94.8 N D 17 East site boundary 24.3 25.6 24.1 25.6 23.7 N D N D N D N D 97.0 98.9 N D 18 Ea st Southea st site bounda ry 22.8 25.1 23.5 23.9 22.8 N D N D N D N D 91.1 95.3 N D 19 Southeast si te boundary 24.7 26.9 25.8 25.7 23.7 N D N D N D N D 98.7 102.1 N D 20 South Southeast site boundary 24.1 26.0 23.8 24.1 22.2 N D N D N D N D 96.4 96.1 N D 21 South site bounda ry 25.5 28.0 25.1 25.6 22.5 N D N D N D N D 101.9 101.3 N D 22 South Southwest site bounda ry 25.5 28.0 25.9 27.5 22.8 N D N D N D N D 102.0 104.2 N D 23 2 miles north of Elliot Road, 3 miles west of Wintersburg Rd 22.7 25.6 23.8 24.2 21.3 ND ND ND ND 90.8 94.8 ND 24 Elli ot Road, 2 miles west of Wi ntersburg at Desert Farms 22.0 24.1 23.6 23.7 19.5 N D N D N D N D 87.8 90.9 N D 25 Elli ot Roa d, 3.5 miles west of Wintersburg a t ca ttle gua rd 23.1 24.5 24.4 24.0 23.0 N D N D N D N D 92.4 95.8 N D 26 Duke Power Plant on entry gate 27.4 28.5 28.5 28.9 29.1 N D N D N D N D 109.5 114.9 N D 27 Southwest site bounda ry 26.7 28.1 26.9 27.9 26.8 N D N D N D N D 106.6 109.7 N D 28 West Southwest site bounda ry 25.4 25.6 26.1 26.1 26.0 N D N D N D N D 101.7 103.8 N D 29 West site bounda ry 23.8 24.5 24.5 24.2 26.0 N D N D N D N D 95.3 99.2 N D 30 West N orthwest site bounda ry 25.1 26.7 24.7 26.4 24.6 N D N D N D N D 100.5 102.4 N D 31 N orthwest site bounda ry 22.7 23.9 22.5 23.2 22.0 N D N D N D N D 90.6 91.6 N D 32 N orth N orthwest site bounda ry 24.8 24.8 25.0 25.4 24.6 N D N D N D N D 99.3 99.9 N D 33 Buckeye Roa d, 0.5 miles west of 359th Ave 25.3 26.8 26.3 25.9 25.9 N D N D N D N D 101.2 104.9 N D 34 Southeast corner of 395th Ave and Van Buren Road 27.6 29.7 27.6 27.6 27.8 N D N D N D N D 110.5 112.7 N D 35 Pal o Verde Inn Fire Station, 40901 W. Osborn Road, Tonopah 30.5 32.5 30.4 31.0 30.9 N D N D N D N D 121.8 124.9 N D 36 Southwest corner of Wintersburg a nd Va n Buren Roa d 25.6 26.8 26.1 26.7 26.0 N D N D N D N D 102.6 105.5 N D 37 Southeast corner of 363rd Ave and Van Buren Road 23.7 24.2 23.6 23.6 24.6 N D N D N D N D 94.6 95.9 N D 38 355th Ave, 0.2 miles south of Buckeye Roa d on ea st side of Rd 26.9 28.1 26.2 28.6 26.8 N D N D N D N D 107.5 109.7 N D 39 343rd Ave, 0.5 miles south of Lower Buckeye Roa d 24.1 25.1 23.2 23.9 24.5 N D N D N D N D 96.3 96.8 N D 40 Wintersburg, Tra nsmission Roa d a t telephone pole 24.5 25.7 24.4 26.5 24.3 N D N D N D N D 98.1 100.9 N D 41 N ew Arlington School 26.2 27.8 25.2 27.4 27.7 N D N D N D N D 104.8 108.1 N D 42 Ruth Fisher School, India n School Roa d a nd Wintersburg Roa d 26.1 29.0 26.8 28.5 26.2 N D N D N D N D 104.6 110.5 N D 43 Winters Well Elementary School 26.5 28.5 26.6 23.8 27.6 N D N D N D N D 106.0 110.7 N D 44 El M irage, 12315 N W Grand Ave. inside rental center 23.9 22.4 21.6 23.2 22.3 N D N D N D N D 71.7 67.8 N D 45 Pal o Verde Central Chemistry Lab, Bldg. E, lead pig 5.2 6.8 6.4 6.9 5.7 ND ND ND N D 20.8 25.8 N D 46 Litchfield Pa rk School, Litchfield & Sa gebrush Roa ds 23.3 26.9 23.4 24.9 25.2 N D N D N D N D 93.2 100.4 N D 47 Littleton School, 115th Ave and Highway 85, Ca shion 23.1 24.2 23.7 24.4 23.7 N D N D N D N D 92.3 96.0 N D 48 Jackrabbit Trail S. of I-10, W si de of road, S of rental center 23.3 23.4 23.7 25.1 23.4 N D N D N D N D 93.3 95.7 N D 49 Pa l o Verde Roa d, 0.25 miles south of I-10 22.1 22.6 23.0 23.8 24.3 N D N D N D N D 88.2 93.7 N D 50 Oli nski Road, 2 miles south of Buckeye-Salome Road 19.2 20.2 19.0 20.7 20.1 N D N D N D N D 76.8 80.0 N D Note 1 - Location 1 Fourth Quarter 2023 TLD 63241 - Anomalous reading. See CR 24-01610 Note 2 - Location 12 Four th Q uar te r - T he 2 TLD s us e d for monitor ing w e r e mis s ing at the time of e x change.

The MA and LA wer e calcu lated us ing 1st, 2nd and 3rd Quarte r Data. BA was calculate d using BQ

• 3.

Docume nte d with C R 24-00356

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 50

10. Land Use Census 10.1 Introduction

In accordance with the PVNGS ODCM, Section 6.2, the f i e l d p o r t i o n o f t h e annual Land Use Census was performed by June 2023.

Observations were made in each of the 16 meteorological sectors to determine the nearest milking animals, residences, and food gardens of greater than 500 square feet that contain broadleaf vegetation.

This census was completed by driving the roads and speaking with residents.

The results of the Land Use Census are presented in Table 10-1 and discussed below. The directions and distances listed are in sectors and miles from the Unit 2 containment.

10.2 Census Results

The 2023 Land Use Census results identified new potential Radiological Effluent Release Report dose receptor locations. Each location was evaluated. The changes identified, and the evaluation results, are described below. The nearest Resident, Milk Animal, and Vegetable Garden were identified as being at the same location; therefore, dose for each of these locations is the same.

Nearest Resident There were no changes in nearest resident status from the previous year. Dose calculations indicated the highest dose to be 0.115 mrem.

Milk Animal There were six (6) changes in milk animal status from the previous year. There were five (5) residential locations with milk animals that indicated having the potential for doses greater than 20% than that of our current sampling location with the lowest dose potential. Three (3) of the five (5) locations had private gates and one (1) resident declined to participate. One (1) residential owner with milk goats agreed to provide samples as part of the REMP. This new doner will be added to the program and was able to start providing samples in 2024. Dose calculations indicated the highest dose to be 0.563 mrem, who is a current REMP participant (Site #49).

Vegetable Gardens There was one (1) change in the nearest gardens identified from the previous year. One (1) location was identified as having the potential for a dose greater than 20% than that of our current sampling location with the lowest dose potential. As of December 2023, the garden was not operational and no signs of preparation for the growing season. Dose calculations indicated the highest dose to be 0.563 mrem, who is a current REMP participant (Site #49).

See Table 10-1 for a summary of the specific results and Table 2-1 for current sample locations. Figure 10-1 through Figure 10-3 provide graphs depicting historical calculated doses for nearest residents, nearest milk receptor, and nearest garden receptor locations in each sector.

Differences in calculated doses are the result of numerous variables, including:

• Changes in receptor locations from year to year (proximity to the power plant)

• Changes in local meteorology (wind direction, wind speed, precipitation, and temperature)

• Concurrent meteorology at the time of effluent releases

• Exposure pathways PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 53 Table 10-1 Land Use Census

(Distance and direction are relative to Unit 2 in miles)

Nearest Nearest Milk Calculated Dose Change from Sector Nearest Resident Garden Animal (mrem) 2022 (Cow/Goat)

Resident 4.21E-2 N 1.55 1.63 1.63 Garden 5.63E-1 Milk 5.63E-1 NNE 1.52 NONE 2.59 Resident 7.55E-2 Milk Milk 3.01E-1 NE 2.37 NONE 3.41 Resident 1.15E-1 Milk Milk 3.95E-1 Resident 1.09E-1 ENE 1.91 3.90 NONE Garden 1.90E-1

E 2.81 NONE 4.23 Resident 6.97E-2 Milk 1.71E-1 Milk ESE 3.03 NONE 3.37 Resident 8.51E-2 Milk 4.36E-1 SE 3.39 NONE 3.66 Resident 9.78E-2 Milk 5.03E-1 Milk SSE NONE NONE NONE NA S NONE NONE NONE NA SSW NONE NONE NONE NA SW 1.48 NONE NONE Resident 1.12E-1 WSW 1.08 NONE NONE Resident 6.90E-2

W 0.79 NONE 1.44 Resident 3.80E-2 Milk Milk 2.29E-1 WNW NONE NONE NONE NA NW 0.92 NONE 3.42 Resident 2.77E-2 Milk 3.86E-2 Resident 2.53E-2 Garden NNW 1.31 4.05 3.68 Garden 5.63E-1 Milk Milk 7.37E-2 Comments: Dose calculations were performed using GASPAR code and 2023 meteorological data and source term. Dose reported for each location is the total for all three PVNGS Units and is the highest individual critical organ dose identified.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 54

11. Summary and Conclusions Summary

The conclusions are based on a review of the radioassay results and environmental gamma radiation measurements for the 2023 calendar year. Where possible, the data were compared to pre-operational sample data.

All sample results for 2023 are presented in Table 8-1 through Table 8-12 and do not include observations of naturally occurring radionuclides, except for gross beta in air and gross beta in drinking water. Table 11-1 summarizes the ODCM required samples and is in the format required by the NRC BTP on Environmental Monitoring.

I-131 i s o c c a s i o n a l l y identified in the e vaporation ponds, Water Resources influent, Water Resources centrifuge sludge, and reservoirs is the result of offsite sources and appears in the effluent sewage from Phoenix. The levels of I-131 detected in these locations are consistent with levels identified in previous years.

Tritium concentrations identified in surface water onsite have been attributed to PVNGS permitted gaseous effluent releases and secondary plant releases. These concentrations are consistent with historical values.

Environmental radiation levels are consistent with measurements reported in previous Pre-operational and Operational Radiological Environmental annual reports, References 1 and 2.

Conclusion

There was no measurable radiological impact on the environment in 2023 resulting from the operation of PVNGS.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 58 Table 11-1 Environmental Radiological Monitoring Program Annual Summary TABLE 11.1 ENVIRONMENTAL RADIOLOGICAL MONITORING PROGRAM ANNUAL

SUMMARY

Palo Verde Nuclear Generating Station Docket Nos. STN 50-528/529/530 Maricopa County, Arizona Calendar Year 2023 Medium or Type and Total Lower All Location with Highest Control Number of Pathway Number of Limit of Indicator Annual Mean Locations Nonroutine Sampled Analyses Detection Locations Reported (Unit of Performed (LLD) Measurements Measurement) (from Table Mean (f)a Name Mean Mean (f)a 6.1) Range (f)a Range Distance and Range Direction

Direct TLD - 199 NA 32.5 Site #35 25.0 (8/8) 24.5 (8/8) 0 Radiation (188/188)

(mrem/std. 16.0 - 31.6 8 miles 19 - 32.5 21.6-28.3 qtr.) 330°

Air Gross Beta - 520 0.01 0.027 Site # 4 0.030 0.042 (52/52) 0 Particulates (468/468) (52/52)

(pCi/m3) 0.006 - 16 miles 0.009 - 0.009 - 0.066 Gamma Spec 0.083 92º 0.083

Cs-134 Composite - 40 0.05 <LLD NA <LLD <LLD 0 (quarterly)

Cs-137 0.06 <LLD NA <LLD <LLD 0

(quarterly)

Air Gamma Spec. - 520 Radioiodine I-131 0.07 <LLD NA <LLD <LLD 0 (pCi/m3)

Broadleaf Gamma Spec. - 20 Vegetation I-131 60 <LLD NA <LLD <LLD 0 (pCi/Kg-wet) Cs-134 60 <LLD NA <LLD <LLD 0 Cs-137 80 <LLD NA <LLD <LLD 0

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 59 Groundwater H 12 2000 <LLD NA <LLD NA 0 (pCi/liter)

Gamma Spec. - 12 Mn-54 15 <LLD NA <LLD NA 0 Fe-59 30 <LLD NA <LLD NA 0 Co-58 15 <LLD NA <LLD NA 0 Co-60 15 <LLD NA <LLD NA 0 Zn-65 30 <LLD NA <LLD NA 0 Zr-95 30 <LLD NA <LLD NA 0 Nb-95 15 <LLD NA <LLD NA 0 I-131 15 <LLD NA <LLD NA 0 Cs-134 15 <LLD NA <LLD NA 0 Cs-137 18 <LLD NA <LLD NA 0 Ba-140 60 <LLD NA <LLD NA 0 La-140 15 <LLD NA <LLD NA 0 Gross Beta - 48 4 3.54 (25/48) Site #55 3.92 (11/12) NA 0 1.71 - 8.71 3 miles 1.74 -8.71 H-3 214° Gamma Spec. - 48 - 16 2000 <LLD NA <LLD NA 0

Drinking Mn-54 15 <LLD NA <LLD NA 0 Water Fe-59 30 <LLD NA <LLD NA 0 (pCi/liter) Co-58 15 <LLD NA <LLD NA 0

Co-60 15 <LLD NA <LLD NA 0 Zn-65 30 <LLD NA <LLD NA 0 Zr-95 30 <LLD NA <LLD NA 0 Nb-95 15 <LLD NA <LLD NA 0 I-131 15 <LLD NA <LLD NA 0 Cs-134 15 <LLD NA <LLD NA 0 Cs-137 18 <LLD NA <LLD NA 0 Ba-140 60 <LLD NA <LLD NA 0 La-140 15 <LLD NA <LLD NA 0

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 60 Milk Gamma Spec. - 22 (pCi/liter) I-131 1 <LLD NA <LLD <LLD 0 <LLD NA <LLD <LLD

Cs-134 15 <LLD NA <LLD <LLD 0 <LLD NA <LLD <LLD

Cs-137 18 <LLD NA <LLD <LLD 0 <LLD NA <LLD <LLD

Ba-140 60 <LLD NA <LLD <LLD 0 La-140 15 <LLD NA <LLD <LLD 0

Surface Water Gamma Spec. - 16 (pCi/liter) Mn-54 15 <LLD NA <LLD NA 0 Fe-59 30 <LLD NA <LLD NA 0 Co-58 15 <LLD NA <LLD NA 0 Co-60 15 <LLD NA <LLD NA 0 Zn-65 30 <LLD NA <LLD NA 0 Zr-95 30 <LLD NA <LLD NA 0 Nb-95 15 <LLD NA <LLD NA 0 I-131 15 <LLD NA <LLD NA 0 Cs-134 15 <LLD NA <LLD NA 0 Cs-137 18 <LLD NA <LLD NA 0 Ba-140 60 <LLD NA <LLD NA 0 La-140 15 <LLD NA <LLD NA 0 H 16 3000 711 (5/16) Site #63 1059 (5/8) NA 0 411-1059 Onsite 180° 411-1059 (a) Mean and range based upon detectable measurements only. Fraction of detectable measurements at specified locations is indicated in parentheses. (f)

NOTE: Miscellaneous samples that are not listed on Tables 2.1 and 9.1 (not ODCM required) are not included on this table.

PVNGS ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT-2023 Page 61

12. Re f e re nce s

1. Pre-Operational Radiological Monitoring Program, Summary Report 1979-1985

2. 1985-2023 Annual Radiological Environmental Operating Reports, Palo Verde Nuclear Generating Station

3. Palo Verde Nuclear Generating Station Technical Specifications and Technical Reference Manual

4. Offsite Dose Calculation Manual, Revision 30, PVNGS Units 1, 2, and 3

5. Regulatory Guide 4.1, Programs for Monitoring Radioactivity in the Environs of Nuclear Power Plants

6. Regulatory Guide 4.8, Environmental Technical Specifications for Nuclear Power Plants

7. NRC Radiological Assessment Branch Technical Position on Environmental Monitoring, Revision 1, November 1979 (Incorporated into NUREG-1301)

8. "Sources of Radiation." NRC: Sources of Radiation. Nuclear Regulatory Commission, 20 March.

2020. Web. 17-Apr-24.

9. "NCRP Report No. 160: Ionizing Radiation Exposure of the Population of the United States."

Journal of Radiological Protection J. Radiol. Prot. 29.3 (2009): 465. Web.

10. NEI 07-07, Nuclear Energy Institute, Industry Groundw ater Protection Initiative - Final Guidance Document, Rev. 1, March 20

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