Text

Independent Spent Fuel Storage Installation, 2020 Annual Radiological Environmental Operating Report
	ML21133A252
Person / Time
Site:	San Onofre
Issue date:	05/11/2021
From:	Bates A; Southern California Edison Co
To:	; Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
	Download: ML21133A252 (69)
	v • d • e

Al Bates

!:i E"DiSO'N An £D!SO INTER ATIONAL Company Manager Regulatory Affairs 10 CFR 50, Appx. I May 11 , 2021 ATTN : Document Control Desk U. S. Nuclear Regulatory Commission Washington , D.C. 20555-0001

Subject:

Docket Nos. 50-206, 50-361, 50-362 and 72-41 2020 Annual Radiological Environmental Operating Report San Onofre Nuclear Generating Station (SONGS), Units 1, 2 and 3 and Independent Spent Fuel Storage Installation In accordance with the San Onofre Nuclear Generating Station (SONGS) Licensee Controlled Specification 5. 7.1.2, Southern California Edison (SCE) is submitting the 2020 Annual Radiological Environmental Operating Report (AREOR) for SONGS Units 1, 2 and 3. The AREOR covers the operation of SONGS during January 1, 2020 through December 31, 2020 and includes summaries, interpretations, and analyses of trends of the results of the Radiological Environmental Monitoring Program (REMP).

In addition, the AREOR includes the results for direct radiation monitoring near the Independent Spent Fuel Storage Installation .

There are no commitments in this letter or the enclosure.

If you have any questions, please contact me at (949) 368-7024.

Enclosure:

2020 San Onofre Nuclear Generating Station Annual Radiological Environmental Operating Report J:6Z5 cc: S. A. Morris, Regional Administrator, NRC Region IV A. M. Snyder, NRC Project Manager, SONGS Units 1, 2 and 3 R.K. Lupo , California Department of Public Health tt/"155 Z/4 JV~/__

/...)t-j.55 P. 0 . Box 128 San Clemente, CA 92672

ENCLOSURE 2020 San Onofre Nuclear Generating Station Annual Radiological Environmental Operating Report

San Onofre Nuclear Generating Station 2020 Annual Radiological Environmental Operating Report

~ I ED I sON .

SOUTH ERN CALI FORNIA License Numbers:

~ DPR-13, NPF-10, NPF-15 An EDISO l TER ATIONAL, Company

2020 AREOR This 2020 Annual Radiological Environmental Operating Report (AREOR) for the San Onofre Nuclear Generating Station (SONGS) fulfills the requirements of the SONGS Licensee Controlled Specification 5.7.1.2 and the Independent Spent Fuel Storage Installation (ISFSI) facility. The 2020 ARE OR covers the results of the environmental monitoring performed around SONGS during the time period January 1, 2020 through December 31 , 2020.

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2020 AREOR Table of Contents 1 Executive Summary ......... ... .. ........................................................................... .... .... ... .. ...... . 1 2 Radiological Environmental Monitoring Program .................... .... .. ... ......... .. .... .. ...... .. ............ 2 3 Land Use Census Results .................................................................................................... 9 4 Quality Assurance .. ............. ...... ... ....... .. .. ... ... .... ... ................ ..... ..... .. ...... ... ..... ...... .. .. .. .. .. ..... 10 5 Program Deviations ... ... ... ..... .. ..... .. .. ... ... ... ... .... ........ .... ............ .. ...................... .. ...... .... .... ... . 11 6 Conclusion ......... ...... ...................... ..... ..... ... .. ................ ... .... .... .... .... ......... ............... .... ... ... . 11 7 References ..... ....... .. ... ...... .... .............. ... ... ... .......... .. ............. ... ... .. ...... ... ........... ... ...... ... .. .... . 11 APPENDIX A. SAMPLE TYPE AND SAMPLING LOCATIONS .... ..... ... ........ .. .......... .. ............... 12 APPENDIX B. RESULTS AND DISCUSSIONS OF 2020 ENVIRONMENTAL DATA ................ 22 APPENDIX C.

SUMMARY

OF QUALITY CONTROL PROGRAMS ........................................... 36 APPENDIX D. COMPARISON OF 2020 REMP DATA TO HISTORICAL DATA ........ ................ 42 APPENDIX E. DEVIATIONS FROM ODCM SAMPLING REQUIREMENTS IN 2020 .... ... ... ... ... 52 APPENDIX F. ERRATA TO PREVIOUS AREORs ......... .... ..................... ...... .. .. ................ .. ...... 54 APPENDIX G. CDPH CO-LOCATED TLDs .. ...................... ...................... ... ..... .. ........ .. .. ......... ..55 APPENDIX H. ISFSI TLD DATA. ..... .. ...... ..... .. .. .. ......... ................................ ............ ..... .. ... ..... ...56 APPENDIX I. OFFSITE GROUND WATER SAMPLING .......... ...... .......................................... 60 Glossary ..... .... ..... ........... .. ............. .............................................................................. ...... .. ... ... 61 FIGURES Figure 1 - SONGS 45 mile REMP Radius ... ...... ...... ... .... ................ ...... ...... ...... .. ............. 3 Figure 2 - SONGS Location ................................. .... ............... .... .... .. ..... .. ..... .... .. ........... . 4 Figure 3 - Examples of Exposure Pathways ....... ... ... ................. ...... .................... ............ 9 Figure 4 - SONGS REMP One Mile Radius .................................... ........ ... ................... 17 Figure 5 - SONGS REMP Two Mile Radius ...... .... ... ................. ............. ....................... 18 Figure 6 - SONGS REMP Five Mile Radius .................................................................. 19 Figure 7 - SONGS REMP 30-mile Radius North .................................... .................... ... 20 Figure 8 - SONGS REMP 45-mile Radius South ............................................. ... .... ... ... 21 Figure 9 - Monthly Average Airborne Particulate Gross Beta Preoperational and Operational Data for Units 2 and 3, (1976 - Jan 2020) ............... .. .......... ........ .. .....44 Figure 10 - SONGS ISFSI and Selected REMP TLD Locations ................. .... ............... 59 Figure 11 - Closest Drinking Water Wells ..... ......................................... ....... ... .... ...... ... . 60 Page I ii

2020 AREOR Acronyms AREOR Annual Radiological Environmental Operating Report ARERR Annual Radioactive Effluent Release Report CDPH California Department of Public Health CEAL Contracted Environmental Analysis Laboratory DOE Department of Energy EAB Exclusion Area Boundary EPA U.S. Environmental Protection Agency ISFSI Independent Spent Fuel Storage Installation LCS Licensee Controlled Specifications LLD Lower Limit of Detection LUC Land Use Census MDC Minimum Detectable Concentration MDD Minimum Differential Dose ND Not Detected NEI Nuclear Energy Institute NRC Nuclear Regulatory Commission ODCM Offsite Dose Calculation Manual QA Quality Assurance QC Quality Control REMP Radiological Environmental Monitoring Program TLD Thermoluminescent Dosimeter Page I iii

2020 AREOR 1 Executive Summary On June 12, 2013, Southern California Edison notified the Nuclear Regulatory Commission (NRC) that it had permanently ceased operation for both Units 2 and 3 on June 7, 2013. While all power operations have ceased , spent fuel remains stored on site. San Onofre Nuclear Generating Station (hereafter referred to as San Onofre or SONGS) continues to fulfill its regulatory commitment to monitor the environment and potential exposure pathways. The Radiological Environmental Monitoring Program (REMP) supports the conclusion that San Onofre has had an inconsequential radiological impact on the environment and that it is well within applicable state and federal regulations.

The REMP includes the sampling of environmental media and measuring radiation levels in the environment surrounding SONGS. Its purpose is to identify any levels of radioactivity or radiation associated with SONGS that have a potential exposure to a member of the general public. This is accomplished through the measurement of direct radiation and by the sampling and analyses of various environmental media, including :

soil

shoreline sediment (beach sand)

air (particulate)

local crops

non-migratory marine species

kelp

drinking water

ocean water

ocean bottom sediments Samples are analyzed for both naturally occurring and SONGS plant related radionuclides.

A detailed description of the 2020 sampling locations and location maps are included in Appendix A of this report.

The California Department of Public Health (CDPH) Drinking Water and Sanitation Laboratory participated in an inter-laboratory split sampling program with SONGS, including ocean water tritium samples and gamma isotopic samples from various environmental media. The results are discussed in Appendix C. The CDPH also conducted a direct radiation (TLD) monitoring program in conjunction with SONGS. Refer to Appendix H.

This report describes the REMP as conducted at SONGS during the period from January 1, 2020 through December 31 , 2020. The REMP produces scientifically defensible data indicating SONGS had no significant radiological environmental impact in 2020. This report fulfills applicable license commitments, as described in the Offsite Dose Calculation Manual (ODCM) , submitted to the NRC as part of the 2020 Annual Radioactive Effluent Release Report (ARERR) .

Beyond the immediate area of the ISFSI , the REMP data collected during 2020, as in previous years, continues to be representative of background levels. The data is summarized in the Statistical Summary of REMP Data found in Appendix 8 . As in previous years, cesium-137 (Cs-137) was identified in soil and fish. Cs-137 in soil is attributable to fallout from nuclear weapons testing and sources external to SONGS, such as the Chernobyl accident. The Cs-137 in fish is consistent with concentrations detected in other west coast marine species and may be attributable to the legacy Pacific Ocean discharges from Fukushima. Cs-137 has been detected at indicator locations, as well as at control locations, in past years. Naturally occurring radionuclides, including beryllium-? (Be-7) , potassium-40 (K-40) , thorium-228 (Th-228) and thorium-230 (Th-230) were detected in both control and indicator locations at similar Page 11

2020 AREOR concentrations and are not related to SONGS. Refer to Appendix B for a more detailed discussion.

There is a natural and manmade radiation background. Natural background is comprised of the terrestrial and cosmic radiation sources while manmade background results from past weapons testing fallout and routine medical applications. Prior to the construction of SONGS, environmental samples and measurements were collected and analyzed to determine the baseline natural radiation levels. The results from the indicator stations are compared to this pre-operational data, as well as control samples, to evaluate if changes in any radiation levels can be attributed to SONGS or other causes such as natural variations in the environment or manmade contributions external to SONGS.

In summary, the environmental monitoring data collected during 2020 supports a conclusion of no adverse effect on the population or the environment from SONGS. The radiation exposures to people living in the surrounding area from SONGS remains less than the detection level, and is a small fraction of the radiation exposures in the environment from the natural background from terrestrial and cosmic radiation .

2 Radiological Environmental Monitoring Program Program Overview The purpose of the REMP is to characterize the radiological environment outside of the Site Boundary and to detect potential radiological impacts resulting from activities at SONGS Units 2 and 3. The REMP monitors credible pathways of exposure to the public and fulfills the radiolog ical environmental monitoring requirements of the ODCM .

Exposure pathways are the different routes by which people can potentially be exposed to radiation or radioactive materials. The pathways may be characterized into four general types, shown below along with a brief description of the monitoring as performed at SONGS :

AIRBORNE. The airborne pathway represents the inhalation intake of airborne radioactive materials. This pathway is sampled in areas around SONGS by continuously drawing air through specialized filters 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months a day, 7 days a week. Although both units at SONGS ceased operation in June 2013, these air samples continue to be collected on a weekly basis.

WATERBORNE. The waterborne pathways include the exposure to radioactive materials accumulated in aquatic biota (fish, shellfish) and in shoreline sediments.

These pathways are assessed through the collection of fish and shellfish samples in the environment around the plant. Sediment samples are also collected to evaluate any long-term buildup in the environment.

INGESTION. The ingestion pathway includes broadleaf vegetation , agricultural products, and food products. Atmospheric releases from the plant can deposit on these food products, representing an intake exposure pathway through the consumption of these food products. Samples of crops (e.g., tomato, lettuce, sorrel) are collected from the local area around the plant to evaluate any impact on this pathway.

DIRECT RADIATION. The direct radiation pathway represents the external exposure from sources on the plant site and directly from any radioactive effluents released to the air or water. This direct environmental radiation dose is measured through the use of direct measurement dosimeters, such as thermoluminescent dosimeters (TLDs) that are placed around the plant site and in the local environment.

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2020 AREOR Site Area and Description San Onofre Nuclear Generating Station is located next to San Onofre State Beach , adjoining Camp Pendleton Marine Corps Base, in San Diego County, 64 miles south of Los Angeles, California. At this time there are no operating reactors, but in the past, there were three operating pressurized water reactors with a total rated capacity of 2664 net megawatts electrical.

Figure 1 - SONGS 45 mile REMP Radius Unit 1, rated at 41 O net megawatts electrical , was supplied by Westinghouse Electric Company.

Unit 1 began commercial operation on January 1, 1968. The unit was permanently shut down on November 30, 1992, and all above-ground structures have been dismantled . By August 31 ,

2004, all fuel was transferred to the ISFSI. By November 29, 2006, all remaining monitored effluent pathways were permanently removed from service or routed to Unit 2 discharge to the outfall. The remaining portions of Unit 1 are owned by Southern California Edison (80%) and San Diego Gas and Electric (20%) .

Unit 2 and Unit 3 were supplied by Combustion Engineering, Inc. , with turbine generators supplied by G.E.C. Turbine Generators, Ltd ., of England. The units began commercial operation in August 1983, and April 1984, respectively , and were rated at 1127 net megawatts electrical each . The twin units are owned by Southern California Edison (78.21 %) , San Diego Gas and Electric (20%) , and the City of Riverside (1 .79%) .

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2020 AREOR

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Figure 2 - SONGS Location Effective December 29, 2006, the City of Anaheim transferred its ownership interests in San Onofre Units 2 and 3 and the entitlement to the Units 2 and 3 output to Southern California Edison Company , except that it retains its ownership interests in its spent nuclear fuel and Units 2 and 3's ISFSI located on the facility's site. In addition , the City of Anaheim retains financial responsibility for its spent fuel and for a portion of the Units 2 and 3 decommissioning costs.

The City of Anaheim remains a licensee for purposes of its retained interests and liabilities.

Southern California Edison notified the NRC on June 12, 2013, that it had permanently ceased operation of Units 2 and 3 on June 7, 2013. The NRC notification , called a Certification of Permanent Cessation of Power Operations, sets the stage for SCE to begin preparations for decommissioning . In a letter to the NRC dated August 7, 2020, SCE certified that all spent fuel has been removed from the Spent Fuel Pools of Units 2 and 3 and on August 10, 2020 had put in place programmatic changes that were previously approved by the NRC for ISFSI-Only operation. SCE continues to monitor environmental conditions in accordance with 10 CFR 50 ,

Appendix I.

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2020 AREOR Sample Collection and Analyses Samples of environmental media were obtained in accordance with the requirements of the ODCM to meet the regulatory requirements. Refer to Appendix A for a complete list of REMP sample locations as described in Table 5-4 of the ODCM .

Indicator samples close to SONGS are compared to control samples located in areas that are beyond the measurable influence of San Onofre. The control sample results are considered representative of background levels with no potential for contribution from releases and sources at SONGS . The control stations also serve as indicators of radioactive sources unrelated to activities at SONGS, such as remote sewage plant discharges of nuclear medicine applications or nuclear fallout attributable to external sources (legacy fallout from nuclear weapons, the nuclear accident at Chernobyl , and the nuclear accident at Fukushima) . The indicator location samples are used to detect environmental radioactivity attributable to SONGS. Indicator sample locations can be located either onsite or offsite.

The SONGS REMP is conducted in accordance with a Quality Assurance Program , meeting the requirements of NRC Regulatory Guide 4.15, Rev. 1. Samples are collected using approved methods; radiochemical analyses of these samples are performed using standardized analytical methods. The Contracted Environmental Analysis Laboratory (CEAL) participates in an inter-laboratory comparison program in partial fulfillment of the quality assurance requirements for environmental monitoring. The CEAL participated in cross check programs which meet the intent of Reg . Guide 4.15. See Appendix C for additional details.

Detection Limit Terminology The NRC requires that equipment and analytical methods used for radiological monitoring must be able to detect specified minimum limits for the type sample and the radionuclide of the analysis. The a priori detection capability for the analytical system used for the measurement is referred to as the Lower Limit of Detection (LLD) . This LLD ensures that radiation measurements are sufficiently sensitive to detect any levels of concern and small changes in the environment. Samples with no detectable radiation levels are typically referred to as less than the Minimum Detectable Concentration (MDC) . The MDC is evaluated for each sample and is used to ensure that the specific analysis has sufficient sensitivity to detect levels consistent with the requirements for analysis by the system LLD. For a more thorough discussion, refer to NUREG/CR-4007.

Lower Limit of Detection (LLD) - The LLD is the a priori (before the fact) lower limit of detection for the method used for the analysis. It is a measure of the detection capability for the analytical method and not for any single sample analysis. This value is calculated for each isotope and every matrix based on typical or expected values of decay time, sample size, counter efficiency, etc. The LLD values are listed in the ODCM and represent the detection capability that the analytical methods must meet for each the specified sample media.

Minimum Detectable Concentration (MDC) - The MDC is the a posteriori (after the fact) lower limit of detection based on actual decay time, measured sample size, and counting efficiency for an individual sample analysis. The MDC is compared to the LLD to verify that the measurement met the ODCM requirements for the maximum value of the LLD for the listed radionuclides. Values flagged by the CEAL as being confirmed above the MDC are presumed to be valid detected levels of radioactivity.

Not Detected (ND) - The term ND refers to TLD data analyzed per ANSI N13.37-2014 (Environmental Dosimetry-Criteria for System Design and Implementation) that is less than the ANSI calculated detection limit above a specific location's baseline. A baseline is calculated per ANSI methods for each specific location because the direct radiation Page 15

2020 AREOR signal is a strong function of very local conditions. If the TLD data for a specific location is less than that specific location's baseline plus the ANSI calculated detection limit, then the value is "ND" for that specific measurement.

The sampling and analyses for the REMP are conducted in accordance with the ODCM and the applicable regulatory requirements.

Regulations and Guidance 10 CFR 50 1 Appendix I 10 CFR 50 , Appendix I establishes the per unit limits on releases of radioactivity to the environment and the resulting dose to the public. These limits are more restrictive than the 10 CFR 20 limits. The 10 CFR 50, Appendix I limits are :

Source NRC Limits for SONGS Liquid Effluent Less than or equal to 3 mrem/yr to whole body from all pathways of exposure Less than or equal to 1O mrem/yr to any organ from all pathways of exposure Gaseous Effluents - Noble Less than or equal to 1O mrad/yr gamma air dose Gases Less than 20 mrad/yr, beta air dose Less than 5 mrem/yr, total body dose to an offsite exposed individual of the public Tritium and particulates with Less than or equal to 15 mrem to any organ for an offsite half-life greater than 8 days individual from all pathways of exposure 40 CFR 190 The Environmental Protection Agency (EPA) has established environmental radiation protection standards in 40 CFR 190 for the uranium fuel cycle that includes nuclear power plants. These limits are applicable to the sum of liquid effluent, gaseous effluents and direct radiation.

The dose limits from all applicable pathways to any offsite individual are:

o 25 mrem/year to the whole body o 75 mrem/year to the thyroid o 25 mrem to any other organ As discussed in the 2020 SONGS ARE RR , the calculated dose to a member of the public as a result of SONGS is a small fraction of the dose standard established by the EPA. This conclusion is supported by the results of the REMP , as reflected by the absence of measurable levels of radiation or radioactive materials in the offsite environment attributable to SONGS.

The following regulatory and industry guidance has been identified as applicable to the SONGS REMP.

US NRC Regulatory Guide 4.1, Programs for Monitoring Radioactivity in the Environs of Nuclear Power Plants, 1975 Page 16

2020 AREOR

US NRC Regulatory Guide 4.2, Preparation of Environmental Reports for Nuclear Power Stations, 1976

US NRC Regulatory Guide 1.109, Calculation of Annual Doses to Man from Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I, 1977

NUREG-1301 , Offsite Dose Calculations Manual Guidance: Standard Radiological Effluent Controls for Pressurized Water Reactors, Generic Letter 89-01 , Supplement No. 1, 1991

US NRG Regulatory Guide 4.13, Revision 2, June 2019, Environmental Dosimetry Performance Specifications, Testing , and Data Analysis

ANSI/HPS N13.37, "Environmental Dosimetry- Criteria for System Design and Implementation", 2014

US NRG Regulatory Guide 4.15, Rev. 1, Quality Assurance for Radiological Monitoring Programs (Normal Operations) - Effluent Streams and the Environment, 1979

NUREG-1576, Multi-agency Radiological Laboratory Analytical Protocols

NUREG/CR-4007, Lower Limit of Detection : Definition and Elaboration of a Proposed Position for Radiological Effluent and Environmental Measurements, 1984 NRC Reporting Limits The NRG has established required reporting levels that represent thresholds above which an investigation is needed to evaluate and ensure compliance with radiation safety standards for the public. Licensed nuclear facilities must prepare a special report if any environmental sample value exceeds the corresponding reporting limit. SONGS did not submit any special reports to the NRG in 2020 as no reporting limits were exceeded .

Summary of Analysis of Results and Trends The 2020 SONGS REMP was conducted in accordance with 10 CFR 50, Appendix I, the SONGS LCS and Section 5.0 of the SONGS ODCM. The REMP sample data have been summarized in the format specified in NUREG-1301 . Data have been evaluated to identify the levels of any plant related environmental radioactivity above background levels (i.e. , plant related contributions that are distinguishable from background) . For data distinguishable from background , a comparison has been made between current environmental monitoring results and pre-operational or previous operational data as appropriate, for trending environmental radioactivity.

To conform with 10 CFR 50 , Appendix I, Section IV B.2, data on measurable levels of radiation and radioactive materials in the environment are provided to allow for a comparison to the predicted (calculated) values in the environment from radioactive material released in effluents.

The tabulated means, ranges, and standard deviations are presented in Appendix B.

Comparisons with background and pre-operational baseline data are presented in Appendix D.

The REMP data are reviewed for accuracy and are compared against NRG reporting levels.

Measurements exceeding the administrative levels (10% of the NRG reporting levels) are flagged. Analyses are performed using instrumentation and methods that provide analytical results with a level of detection as required by the ODCM. The a posteriori MDC is compared to the maximum value for the a priori LLD specified in the ODCM . This ensures that regulatory limits for the maximum LLD are met.

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2020 AREOR Table 1 - Maximum LLDs as Specified in SONGS ODCM Airborne Marine Local Particulate Animals Crops Sediment Water or Gases (pCi/kg , (pCi/kg, (pCi/kg, Anal sis Ci/L Ci/m 3 wet wet d Gross beta 4 1E-02 H-3 2000 Mn-54 15 130 Fe-59 30 260 Co-58, 60 15 130 Zn-65 30 260 Zr-95, Nb-95 15 1-131 1 Cs-134 15 130 150 Cs-137 18 150 180 Ba-140, La-140 15 The impact of SONGS on the surrounding environment is assessed through a series of analyses . These analyses include: comparisons of indicator to control locations (Appendix B) ;

comparison of 2020 REMP data to historical environmental data (Appendix D) ; and the summary of deviations from sampling requirements and corrective actions taken (Appendix E).

A detailed discussion of the 2020 analytical results is presented in this report. Analytical values from offsite indicator sample stations continue to trend with the control stations. The data indicate that SONGS had no significant radiological impact on the environment during 2020.

In addition , dose to members of the public attributable to SONGS related radiological activities remain well below regulatory limit of 100 mrem per year, as specified in 10 CFR 20 , § 20.1301 and in keeping with the philosophy of "as low as is reasonably achievable" (ALARA) , as specified in 10 CFR 20.1101 (b).

The data are summarized in the Statistical Summary of REMP Data found in Appendix B. The level of Cs-137 found in control and indicator samples is consistent with historical and expected data. The Cs-137 is attributable to fallout from legacy atmospheric nuclear weapons testing , to fallout from Chernobyl , and to the legacy Fukushima discharges into the Pacific Ocean .

Naturally occurring radionuclides, including beryllium-? (Be-7) , potassium-40 (K-40) ,

thorium-228 (Th-228) and thorium-230 (Th-230) were detected in both control and indicator locations at similar concentrations and are not related to SONGS. Refer to Appendix B for a more detailed discussion.

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2020 AREOR 3 Land Use Census Results l I t,o,, 1111d $uOm61,-

Figure 3 - Examples of Exposure Pathways In accordance with the ODCM , each year a Land Use Census (LUC) is performed to identify any changes in the use of areas at and beyond the site boundary. Modifications to the monitoring program may be made if the LUC identifies either new pathways of exposure, or significant changes to the existing pathways around the plant. The 2020 LUC did not identify any new pathways.

Summary of Changes to the LUC:

The 2020 LUC did identify some minor changes to the occupancy and location of some existing receptors. Based on data from the Camp Pendleton base Game Warden the distance to the closest deer habitat range was adjusted for each sector. The occupancy of some employment locations changed because of impacts from the COVID pandemic. The findings of the 2020 LUC did not require any changes to the sampling media or the sample locations listed in the current monitoring program .

Land Use Changes identified in the 2020 LUC report:

The 2019 LUC reported the distance between SONGS and the area closest to SONGS containing vegetation that may be consumed by deer. The 2020 LUC reports the distance between SONGS and the area closest to SONGS containing deer habitat as reported by the Camp Pendleton Base Game Warden . This revision changes the location for the deer consumption pathway in all landward sectors.

The occupancy for the State Parks Surfing Beach entrance structure changed from 1500 hours0.0174 days 0.417 hours 0.00248 weeks 5.7075e-4 months to 2000 hours0.0231 days 0.556 hours 0.00331 weeks 7.61e-4 months .

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2020 AREOR

The occupancy for the State Parks Surfing Beach life-guard tower changed from 800 hours0.00926 days 0.222 hours 0.00132 weeks 3.044e-4 months to 1000 hours0.0116 days 0.278 hours 0.00165 weeks 3.805e-4 months .

The Endless Summer Surf Camp overnight activity did not occur in 2020 because of the COVID pandemic.

LUC # R-G 1 (San Onofre State Park campground host) occupied spaces 103 to 104 in 2020. Two hosts occupied this location for six months each. The Campground host (located adjacent to the former Endless Summer Surf Camp) was occupied by two hosts each on site for six months in 2020. Occupancy changed to 4380 hours0.0507 days 1.217 hours 0.00724 weeks 0.00167 months for 2020 - adult only. No other age group occupied this location. In 2019 this location was reported as Full Time Residence "FTR."

Deleted LUC# 22 (SCE land uses). This location referred to the SONGS Mesa facility .

Members of the general public are not allowed on the SONGS Mesa and there is no specific location to map.

4 Quality Assurance A portion of REMP sampling activity is devoted to quality assurance. All REMP activities ,

including support contractors, are assessed as defined in Regulatory Guide 4.15, Rev. 1. The quality assurance program 's main aspects include process quality control , instrument quality control, comprehensive data reviews, cross-check analyses, and audits. Routine REMP assessments ensure that the program , procedures and personnel are performing satisfactorily.

Samples are collected using approved methods; radiochemical analyses of these samples are performed using standardized analytical methods. Quality audits and independent technical reviews help determine areas that need attention. These areas are addressed in accordance with the station's Corrective Action Program .

The CDPH participates in a split sampling program in accordance with the site's REMP procedures. Duplicate radiological split sampling is performed by SONGS to demonstrate repeatability of the sample collection , preparation , and analysis process . Split sample analysis is performed for the evaluation of the precision and bias trends of the method of analysis without the added variables introduced by sampling . The 2020 CDPH data resulted in similar conclusions to the 2020 SONGS REMP data.

GEL Laboratories, LLC (GEL) performs the radiochemistry analysis of samples noted within this report. GEL performs the requested analysis under its Quality Assurance Program , which meets the requirements of 10 CFR 50, Appendix B, ASME NQA-1 and Regulatory Guide 4.15 Revision 1. The measurement capabilities of the radiological laboratory are demonstrated by participating in an inter-laboratory measurement assurance program and performing duplicate and split sample analyses. Approximately 10% of the analyses performed are quality control samples , consisting of inter-laboratory measurement assurance program samples, duplicate samples, and split samples. The inter-laboratory measurement assurance program provides samples that are similar in matrix and size to those sampled and measured by the REMP . This program assures that equipment calibrations and sample preparation methods accurately measure radioactive material in samples. See Appendix C for detailed QA measurement data.

Stanford Dosimetry performs the environmental TLD analyses noted in this report. Stanford Dosimetry performs the requested analyses under its Quality Assurance Program which meets the requirement of 10 CFR 50, Appendix B, ASME NQA-1 , Regulatory Guide 4.15 Revision 1 and Regulatory Guide 4.13 Revision 2 (Environmental Dosimetry - Performance Standards, Testing and Data Analysis) .

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2020 AREOR 5 Program Deviations Any deviation in the conduct of the program as required , either in terms of sample collection or analysis, requires an investigation as to the cause and identification of measures to prevent recurrence. Deviations from the sampling program or sensitivity requirements are acknowledged and explained in Appendix E to this report.

6 Conclusion Radiological environmental data collected throughout 2020 have been evaluated to determine if SONGS had any measurable impact on the surrounding environment.

The Cs-137 detected in soil and fish is due to factors external to SONGS. The Cs- 137 in soil is attributable to the legacy fallout from nuclear weapons testing and to the fallout from the Chernobyl accident. The Cs-137 in fish is attributable to the legacy discharges to the Pacific Ocean from Fukushima. The work process at SONGS during 2020 had an insignificant radiological impact on the environment.

7 References

1. SONGS Offsite Dose Calculation Manual (ODCM) , Section 5.0 .

2. SONGS Radiological Monitoring (RM) Procedures established for the Radiological Environmental Monitoring Program.

3. NUREG/CR-4007, "Lower Limit of Detection: Definition and Elaboration of a Proposed Position for Radiological Effluent and Environmental Measurements," August 1984.

4. The Procedures Manual of the Environmental Measurements Laboratory (US DOE HASL-300)

Page I 11

APPENDIX A 2020 AREOR APPENDIX A. SAMPLE TYPE AND SAMPLING LOCATIONS Table 2 - Direct Radiation Measuring Locations DISTANCE* DIRECTION*

DIRECT RADIATION MEASURING LOCATION (miles) (Sector) 1 City of San Clemente (Former SDG&E Offices) (Control) 5.7 NW 2 Camp San Mateo - (MCB , Camp Pendleton) 3.6 N 3 Camp San Onofre - (MCB, Camp Pendleton) 2.8 NE 4 Camp Homo - (MCB, Camp Pendleton) 4.4 E 6 Old El Camino Real (AKA Old Highway 101) 3.0 ESE 8 Noncommissioned Officers Beach Club 1.4 NW 10 Bluff 0.7 WNW 11 Former Visitors Center 0,4b NW 12 South Edge of Switchyard 0.2b E 13 Southeast Site Boundary (Bluff) 0,4b ESE 15 Southeast Site Boundary (Office Building) 0.1 b SSE 16 East Southeast Site Boundary 0,4b ESE 19 San Clemente Highlands 4.9 NNW 22 Former US Coast Guard Station - San Mateo Point 2.7 WNW 23 SDG&E Service Center Yard (Control) 8.1 NW 31 Aurora Park - Mission Viejo (Control) 18.6 NNW 33 Camp Talega - (MCB , Camp Pendleton) (Control) 5.9 N 34 San Onofre School - (MCB , Camp Pendleton) 1.9 NW 35 Range 312 - (MCB , Camp Pendleton) 4.8 NNE 36 Range 208C - (MCB , Camp Pendleton) 4.1 NE 38 San Onofre State Beach Park 3.4 SE 40 SCE Training Center - Mesa 0.7 NNW 41 Old Route 101 - East 0.3b E 44 Fallbrook Fire Station (Control) 17.7 E 46 San Onofre State Beach Park 1.0 SE 47 Camp Las Flores - (MCB , Camp Pendleton) (Control) 8.6 SE 49 Camp Chappo - MCB (Control) 12.9 ESE 50 Oceanside Fire Station (Control) 15.6 SE 53 San Diego County Operations Center (Control) 44.2 SE 54 Escondido Fire Station (Control) 31 .8 ESE Page I 12

APPENDIX A 2020 AREOR DISTANCE* DIRECTION*

DIRECT RADIATION MEASURING LOCATION (miles) (Sector) 55 San Onofre State Beach (U1 West) 0.2 b WNW 56 San Onofre State Beach (U1 West) 0.2 b w 57 San Onofre State Beach (Un it 2) 0.1 b SW 58 San Onofre State Beach (Unit 3) 0.1 b s 59 SONGS Meteorological Tower 0.3 b WNW 61 Mesa - East Boundary 0.7 N 62 MCB - Camp Pendleton 0.7 NNE 63 MCB - Camp Pendleton 0.6 NE 64 MCB - Camp Pendleton 0.6 ENE 65 MCB - Camp Pendleton 0.7 E 66 San Onofre State Beach 0.6 ESE 67 Former SONGS Evaporation Pond 0.6 NW 68 Range 21 0C - (MCB , Camp Pendleton) 4.4 ENE 73 South Yard Facility 0.4 b ESE 74 Oceanside City Hall (Backup Control) 15.6 SE 75 Gate 25 MCB 4.6 SE 76 Former El Camino Real Mobil Station 4.6 NW 77 Area 62 Heavy Lift Pad 4.2 N 78 Homo Canyon (AKA Sheep Valley) 4.4 ESE Table 3 - Airborne Radioactivity Sampling Locations AIRBORNE (AP and AC) SAMPLING LOCATION DISTANCE* DIRECTION*

(miles) (Sector) 1 City of San Clemente (City Hall) 5.1 NW 7e AWS Roof 0.18 b NW 9 State Beach Park 0.6 ESE 10 e Bluff 0.7 WNW 11 e Mesa EOF 0.7 NNW 12 Former SONGS Evaporation Pond 0.6 NW 13 Marine Corp Base (Camp Pendleton East) 0.7 E 16 San Luis Rey Substation (Control) 16.7 SE Page I 13

APPENDIX A 2020 AREOR Table 4 - Soil Sampling Locations SOIL (TSC SO) SAMPLING LOCATIONc DISTANCE* DIRECTION*

(miles) (Sector) 1 Camp San Onofre 2.8 NE 2 Old Route 101 - (East Southeast) 3.0 ESE 3 Basilone Road / 1-5 Freeway Off ramp 2.0 NW 5 Former Visitors Center 0.4 b NW 7 Prince of Peace Abbey - Oceanside (Control) 15 SE Table 5 - Ocean Water Radioactivity Sampling Locations OCEAN WATER (SW) SAMPLING LOCATION DISTANCE* DIRECTION*

(miles) (Sector)

A Station Discharge Outfall - Unit 1 0.6 SW B Outfall - Unit 2 1.5 SW C Outfall - Unit 3 1.2 SSW D Newport Beach (Control) 30.0 NW Table 6 - Drinking Water Radioactivity Sampling Locations DRINKING WATER (WGC DW) SAMPLING LOCATION DISTANCE* DIRECTION*

(miles) (Sector) 4 Camp Pendleton Drinking Water Reservoir 2.0 NW 5 Oceanside City Hall (Control) 15.6 SE Table 7 - Shoreline Sediment Radioactivity Sampling Locations SHORELINE SEDIMENT (SSA SO) SAMPLING LOCATION DISTANCE* DIRECTION*

(miles) (Sector) 1 San Onofre State Beach (Southeast) 0.6 SE 2 San Onofre Surfing Beach 0.8 WNW 3 San Onofre State Beach (Southeast) 3.5 SE 4 Newport Beach North End (Control) 29.2 NW Table 8 - Local Crops Sampling Locations LOCAL CROPS SAMPLING (TFB VG) LOCATION DISTANCE* DIRECTION*

(miles) (Sector) 2 Oceanside (Control) 15 to 25 SE to ESE 6 SONGS Garden Mesa EOF 0.7 NNW Page 114

APPENDIX A 2020 AREOR Table 9 - Non-Migratory Marine Animal Sampling Locations MARINE ANIMAL (MOA) SAMPLING LOCATION DISTANCE

DIRECTION *

(miles) (Sector)

A Un it 1 Outfall 0.9 WSW B Units 2/3 Outfall 1.5 SSW C Laguna Beach (Control) 20 to 25 WNW to NW Table 1O - Kelp Sampling Locations KELP (VG) SAMPLING LOCATION d DISTANCE* DIRECTION*

(miles) (Sector)

A San Onofre Kelp Bed 1.5 s B San Mateo Kelp Bed 3.8 WNW C Barn Kelp Bed 6.3 SSE to SE E Salt Creek (Control) 11 to 13 WNW to NW Page I 15

APPENDIX A 2020 AREOR Table 11 - Ocean Bottom Sediment Sampling Locations OCEAN BOTTOM (SEB SO) SAMPLING LOCATION DISTANCE* DIRECTION*

(miles) (Sector)

B Unit 1 Outfall 0.8 SSW C Unit 2 Outfall 1.6 SW D Unit 3 Outfall 1.2 SSW E Laguna Beach (Control) 20-25 NW F SONGS Up-coast 0.9 WSW NOTES for TABLES 3 - 11:

a Distance (miles) and Direction (sector) are measured relative to Units 2/3 midpoint as described in the ODCM .

Direction determined from degrees true north.

b Distances are within the Un its 2/3 Excl us ion Area Boundary (EAB) c Soil samples are not requ ired by the SONGS ODCM.

d Kelp samples are not requ ired by the SONGS ODCM.

e Not required by the SONGS ODCM .

MCB = Marine Corps Base (Camp Pendleton )

Table 12 - Sector and Direction Designations DEGREES TRUE NORTH NOMENCLATURE FROM SONGS 2 AND 3 MIDPOINT Sector Center Sector 22.5° Direction Limit Line Limit Sector 348.75 0 & 360 11 .25 A N 11 .25 22.5 33.75 B NNE 33.75 45.0 56.25 C NE 56.25 67.5 78.75 D ENE 78.75 90.0 101 .25 E E 101 .25 112.0 123.75 F ESE 123.75 135.0 146.25 G SE 146.25 157.0 168.75 H SSE 168.75 180.0 191 .25 J s 191 .25 202.5 213.75 K SSW 213.75 225.0 236.25 L SW 236.25 247.5 258.75 M WSW 258.75 270.0 281 .25 N w 281 .25 292.5 303.75 p WNW 303.75 315.0 326.25 Q NW 326.25 337 .5 348.75 R NNW Page I 16

APPENDIX A 2020 AREOR P.4.ClFIC OC.EAN San Onofre REIMP One-Mile Radius C *m l.iGdl)C n*

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APPENDIX A 2020 AREOR 15--mile/

San Onofre REMP radius 4S..M le South Figure 8 - SONGS REMP 45-mile Radius South Page 121

APPENDIX B 2020AREOR APPENDIX B. RESULTS AND DISCUSSIONS OF 2020 ENVIRONMENTAL DATA Summary The 2020 REMP analysis results support the conclusion that the measured levels of radioactivity in samples collected are attributable to sources external to SONGS (fallout and ongoing liquid discharges to the Pacific Ocean from the nuclear accident at the Fukushima Daiichi Nuclear Power Station , Chernobyl , and residual fallout from legacy atmospheric nuclear weapons testing) . Cs-137 has been intermittently detected in the indicator and in the control soil samples in past years and no correlation between Cs-137 level in soil and proximity to the plant has been observed . The CS-137 detected in both indicator and control samples of non-migratory marine animals is attributable to sources external to SONGS. The direct radiation results (from TLD data) are ND (not detected) outside the immediate area of the ISFSI.

Results and Discussions of 2020 Environmental Data Direct Radiation Direct gamma radiation is monitored in the environment by calcium sulfate (CaSO4) TLDs placed at 49 locations and analyzed quarterly per the methodology described in Regulatory Guide 4.13 revision 2 (based on ANSI/HPS N 13.37-2014, "Environmental Dosimetry - Criteria for System Design and Implementation"). The Annual Public Dose, as referenced in Table 13, is based on the potential member of the public exposure at the listed locations. For onsite locations, at or near the EAB, the occupancy factor is determined per site procedure for Direct Radiation Exposure Controls and Monitoring . The hypothetical maximum associated exposure to a member of the general public, adjusted for occupancy, is less than the minimum detectable dose as calculated using the ANSI method.

The 2020 quarterly dose measurements (accounting for background) at all TLD locations outside the SONGS EAB were ND. The criteria for establishing a detectable dose, in accordance with Reg . Guide 4.13 , is 5 mrem per quarter above the baseline and 10 mrem per year. Dose measurements less than these values are reported as ND. In accordance with ANSI N 13.37 , the annual facility dose is calculated using the sum of the four quarterly dose measurements and subtracting the annual baseline. Refer to Table 13 for a summary of all 2020 SONGS REMP TLD data. The data for offsite locations indicate no significant change since 2019.

The 2020 REMP quarterly dose measurements within the EAB were detectable at TLD 55 and at TLD 13. REMP TLD 13, Southeast Site Boundary (Bluff) is within the EAB at the southwest corner of SONGS facility footprint and has been used for radioactive equipment and materials storage for a number of years; TLD location 13 is not readily accessible to the public. REMP TLD 55 , (located on the beach walkway between the ISFSI and the ocean) , is readily accessible to the general public and had detectable quarterly dose measurements during the first three quarters of 2020 when TLD 55 data was available. REMP TLD 55 data includes the estimated neutron dose. In 2020, the measurable doses at REMP TLD 55 are attributable to the loading operation of the SONGS ISFSI located in the near vicinity.

The annual dose measurements at TLD 13, TLD 55, TLD 56 , TLD 59, and TLD 73 were also detectable. The detectable dose measurement at TLD 73 (located close to TLD 13) is also attributable to the transport, loading and storage of radioactive materials at SONGS. The detectable dose measurements at TLDs 56 (located close to 55) is also attributable to the operation of the ISFSI. The measured dose rates at TLD 59 can be attributed to a locally elevated baseline dose rate at this location. There are no SONGS related activities near TLD Page I 22

APPENDIX B 2020 AREOR 59 that could account for the elevated dose rate observed here. The area around TLD 59 is not accessible to members of the general public.

Separate TLDs are used to compensate for transit dose and a fade TLD is used to evaluate for the time and temperature dependent "fade" that may affect dosimeter data. After the samples were analyzed , the measured doses were corrected for pre and post field exposure times.

A neutron dosimeter package was co-located with REMP TLD 55 and at selected ISFSI TLD locations around the ISFSI. Any detected neutron dose was added to the gamma dose to report a total dose for each station with a neutron package. The maximum detected neutron dose in any quarter of 2020 was 3.0 mrem at some of the SONGS ISFSI locations. This was due to the increased movement and storage of spent fuel at the SONGS ISFSI.

The fourth quarter 2020 data for TLDs 55 and 56 was not available. In accordance with the ANSI guidance, a normalized annual dose to members of the general public was calculated for TLDs 55 and 56 based on the three quarters of available data. In addition , two supplemental dosimeters were deployed at two locations between TLD 55 and 56 along the seawall. Data from the supplemental locations was available for all of 2020. The empirical data gathered from these four locations immediately adjacent to the ISFSI indicate that dose to a member of the general public was less than one millirem per year based on the estimated occupancy at this location as per the ANSI guidance.

Direct Radiation baseline evaluation and estimation of natural background An in-depth baseline exposure analysis of the environmental radiation results for the period of 2001 through 2010 was completed for all the REMP TLD monitoring locations. It was determined that if the standard deviation was low and no additional exposure above background was identified at a particular station , the average of that station's radiation exposure results should be equal to natural background (baseline) at that location. The baseline results for REMP TLDs have been summarized with the annual and quarterly values in Table 13.

Natural background radiation is variable and a minor shift in location can yield a measurable change in background radiation. Therefore, if a TLD is moved , the baseline (background) for that location may be affected. The natural direct gamma radiation varies according to location because of differences in the natural radioactive materials in the soil , soil moisture content, buildings, and other factors.

The baseline environmental exposure analysis included an assessment of the standard deviation of the quarterly results and annual totals at each location. This is an appropriate methodology to determine the ability to detect radiation exposure above background , described in ANSI/HPS N13.37-2014. The 2020 quarterly and annual results expressed in Table 13 are positive exposures if they exceed either 5 mrem above the baseline quarterly or 1O mrem above the baseline annually. If not, the measurement is noted as ND.

In 1980 the Department of Energy (DOE) conducted an Aerial Radiological Survey of SONGS and the surrounding area . The currently used baseline/background value of 15.8 mrem per standard quarter within the SONGS EAB is consistent with the 1980 gamma exposure rates reported by the DOE for the areas immediately north and south of SONGS , taking into account the reduction in environmental radioactivity and background dose rates caused by the decay of atmospheric nuclear weapons testing fallout since 1980.

An empirical determination of the background baseline for stations within the EAB is not possible due to the known plant related radiological activities (e.g., storage and transport of radioactive materials) that occurred during the baseline calculation study period . The average of nearby proxy locations outside the EAB was used to estimate the baseline within the EAB. A value of 15.8 mrem per quarter was determined as the appropriate baseline for the REMP Page 123

APPENDIX B 2020 AREOR stations located within the EAB. However, local baseline variations within the EAB are possible because the baseline study period did not predate the introduction of licensed material to the REMP TLD locations within the EAB.

Page 124

APPENDIX B 2020 AR EOR Table 13 - SONGS REMP TLD Data TLD 2020 Quarterly Results Baseline Adjusted Quarterly Annual Annual Qtr. Annual Annual Location Distance Baseline (mrem) Results Facility Public

1 (miles) (mrem) Baseline Total (mrem) (mrem) (mrem) Dose Dose (SCE-#) (mrem) (mrern) 1 2 3 4 1 2 3 4 1 City of San Clemente 5.7 18.4 18.4 17.9 18.0 19.2 ND ND ND ND 73.6 73.5 ND ND 2 Camp San Mateo - MCB 3.6 19.6 18.4 20.0 18.5 21.0 ND ND ND ND 78.2 77.9 ND ND 3 Camp San Onofre - MCB 2.8 17.2 16.7 18.1 17.8 18.7 ND ND ND ND 69.0 71.2 ND ND 4 Camp Horno - MCB 4.4 19.0 17.5 18.7 17.8 20. 1 ND ND ND ND 76.1 74.2 ND ND 6 Old Route 101 (ESE) 3.0 12.0 10.0 12.4 9.9 12.7 ND ND ND ND 47.9 45.0 ND ND Noncom missioned Officers' 8

Beach Club 1.4 16.2 15.2 15.7 15.1 16.7 ND ND ND ND 64.8 62.7 ND ND 10 Bluff 0.7 17.2 16.6 16.1 16.2 17.6 ND ND ND ND 69.0 66.6 ND ND 19 San Clemente Highland s 4.9 18.7 19.0 19.1 18.9 19.2 ND ND ND ND 74.8 76.2 ND ND Former US Coast Guard 22 Station 2.7 18.8 18.4 18 .7 19.0 20.2 ND ND ND ND 75.3 76.2 ND ND SDG&E Service Center Yard 23 (Control) 8.1 16.6 16.0 16.4 15.7 16.6 ND ND ND ND 66.4 64.8 ND ND Aurora Park - Mission Viejo 31 (Control) 18.6 19.4 20.3 19.8 19.4 20.0 ND ND ND ND 77.8 79.5 ND ND Camp Talega - MCB 33 (Control) 5.9 19.9 18.5 19.8 18.4 20.4 ND ND ND ND 79.5 77.1 ND ND 34 San Onofre School - MCB 1.9 17.0 16.9 17.3 16.8 17.4 ND ND ND ND 68. 1 68.4 ND ND 35 Ra nge 312 - MCB 4.8 17.8 15.3 16.8 14.8 16.9 ND ND ND ND 71 .1 63.8 ND ND 36 Range 208C - MCB 4.1 20.5 18.8 21.0 19.1 21.1 ND ND ND ND 82.0 79.9 ND ND 38 San Onofre State Beach Park 3.4 15.0 12.4 14.9 13.0 13.9 ND ND ND ND 60.1 54.2 ND ND 40 SCE Tra ining Center - Mesa 0. 7 18.0 17.4 18.6 17.6 18.7 ND ND ND ND 71.9 72.2 ND ND Fall brook Fire Station 44 (Control) 17.7 14.7 15 .4 15.5 15.4 15.8 ND ND ND ND 58.9 62.2 ND ND 46 San Onofre State Beach Park 1.0 12.8 12.9 14.8 13.0 14.3 ND ND ND ND 51.3 54.9 ND ND Camp Las Flores - MCB 47 (Control) 8.6 14.0 15 .8 15.6 16.0 17.0 ND ND ND ND 55.9 64.4 ND ND Camp Chappo - MCB 49 (Control) 12.9 14.9 15.5 15.0 15.3 16.4 ND ND ND ND 59.7 62. 3 ND ND Oceanside Fire Station 50 (Control) 15.6 17.4 17.5 17.3 16 .4 18.3 ND ND ND ND 69.8 69.5 ND ND San Diego County 53 Operations Center (Control) 44.2 19.1 19.8 20.1 19.3 20.0 ND ND ND ND 76 .5 79.3 ND ND Escondido Fire Station 54 (Control) 31.8 16.9 18.7 18.6 18.8 19.8 ND ND ND ND 67.7 75.9 ND ND '

61 Mes a - East Boundary 0.7 16.2 15.3 16.3 14.8 16.5 ND ND ND ND 64.8 62.9 ND ND 62 Camp Pendleton 0.7 13.9 12.4 14.1 12.0 13.7 ND ND ND ND 55.5 52.2 ND ND 63 Camp Pendleton 0.6 14.6 13.2 15.1 13.9 14.7 ND ND ND ND 58.4 57.0 ND ND 64 Camp Pendleton 0.6 15.8 15.0 15.9 14.3 16.3 ND ND ND ND 63.1 61.5 ND ND Page I 25

APPENDIX B 2020 AREOR Baseline Adjusted Quarterly Annual Annual TLD Qtr. 2020 Quarterly Results Annual Annual Distance Results Facility Public

1 Location Baseline (mrem) Baseline Total (miles) (mrem) Dose Dose (SCE-#) (mrem) (mrem) (mrem) 1 2 3 4 1 2 3 4 (mrem) (mrem) 65 Camp Pendleton 0.7 14.1 13.0 14.3 12.5 14.7 ND ND ND ND 56.3 54.5 ND ND 66 San Onofre State Beach 0.6 14.7 14.1 14.7 14.1 16.2 ND ND ND ND 58.9 59.1 ND ND Former SONGS Evaporation 67 Pond 0.6 17.8 17.7 17.4 17.2 19.0 ND ND ND ND 71.1 71.3 ND ND 68 Range 210C - MCB 4.4 15.8 15.6 17.8 15.7 18.0 ND ND ND ND 63.1 67.2 ND ND Oceanside City Hall (Backup 74 Control) 15.6 14.0 13.5 13.9 13.5 14.8 ND ND ND ND 55.9 55.6 ND ND 75 Gate 25 MCB 4.6 16.7 15.9 17.7 15.9 17.9 ND ND ND ND 66.9 67.3 ND ND 76 El Camino Real Mobil Station 4.6 18.2 17.8 18.2 18.4 19.0 ND ND ND ND 72.7 73.4 ND ND 77 Area 62 Heavy Lift Pad 4.2 20.2 17.8 20.4 18.6 20.4 ND ND ND ND 80.7 77.1 ND ND 78 b Homo Canyon 4.4 11 .7 11.5 - - - ND - - - 46.7 - - .

11 Former Visitors' Center 0.4* 15.8 16.4 16.0 16.4 17.5 ND ND ND ND 63.1 66.3 ND ND 12

South Edge of Switchyard 0.2* 15.8 18.4 17.9 16.6 19.4 ND ND ND ND 63.1 72.3 ND ND 13 e Southeast Site Boundary 0.4* 15.8 6.0 5.6 ND 5.0 63.1 84.7 21.6 ND (Bluff)

21.8 21.4 20.7 20.8 15 ab Southeast Site Boundary 0.1* 15.8 ND ND ND ND 63.1 71.7 ND ND (Office BldQ) ' 17.4 18.2 17.5 18.6 16 '

East Southeast Site 0.4* 15.8 ND ND ND ND 63.1 68.2 ND ND Boundary

17.3 17.1 16.8 17.0 41 C Old Route 101 - East 0.3* 15.8 15.6 17.3 15.0 17.1 ND ND ND ND 63.1 64.9 ND ND 55 a bd San Onofre State Beach (U1 0.2* 15.8 5.2 6.8 5.9 - 63.1 86.9 23.8 ND West) 21.0 22.5 21.7 -

56 ab San Onofre State Beach (U1 0.2* 15.8 ND ND ND - 63.1 75.2 12.2 ND West) 19.2 18.5 18.7 -

57

San Onofre State Beach (Unit 0.1* 15.8 ND ND ND ND 63.1 70.8 ND ND

2) 18.3 17.2 17.6 17.7 58 ° San Onofre State Beach (Unit 0.1* 15.8 ND ND ND ND 63.1 71.9 ND ND

3) 18.0 17.8 18.0 18.1 59 C SONGS Meteorological 0.3* 15.8 ND ND ND ND 63.1 79.5 16.4 ND Tower 20.1 20.0 19.4 19.9 73 C South Ya rd Facility 0.4* 15.8 19.0 18.8 17.8 19.4 ND ND ND ND 63.1 75.0 11.9 ND Indicates that the station is within the EAB . The baseline has been estimated to be 15.8 mrem per standard 91-day quarter within the EAB .

a The dose to members of the public is based on a default non-office area annual occupancy time of 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months per year.

b TLD 55 and TLD 56 were not on station for the fourth quarter 2020 . The annual dose was estimated based on the remaining three quarter's data per ANSI guidance. TLD 78 data was not available for three quarters due to construction activity. An annual dose for TLD 78 is not available due to the lim ited amount of data.

C This location is not accessible to members of the general publ ic d A neutron dosimeter was co-located with REMP TLD 55 and selected ISFSI TLDs. The estimated neutron dose was added to the gamma dose.

e Adjusted for occupancy in accordance with Radiation Monitoring and Exposure Controls procedure.

For off-site locations with no available occupancy the public dose is ND.

Page 126

APPENDIX B 2020 AREOR Quality Control Duplicate Direct Radiation Samples Duplicate Quality Control (QC) TLD was installed adjacent to TLD 66 and TLD 67. The duplicate TLDs agreed closely with the indicator TLDs , see Appendix C for results. These TLDs were not required by the ODCM and are not included in the Statistical Summary of REMP Data.

ISFSI Direct Radiation Samples ISFSI TLDs were placed in the vicinity of the ISFSI. Though data from these TLDs are not included in the statistical summary of REMP data because they are not part of the ODCM , the ISFSI data are listed and discussed in Appendix I.

Airborne Particulate, Iodine, and Composite Isotopic Analyses Air particulate samples were collected from the control location (#16) and seven indicator stations, including four stations required by the ODCM (#1 , #9, #12, and #13) and three optional stations (#7, #10 , and #11) not required by the ODCM . The data from these eight stations are included in the statistical summary. The samples were analyzed for gross beta activity , 1-131 ,

and composited quarterly for gamma isotopic analysis. Air Sampler #7 (AWS roof) was permanently removed from service in November 2020 due to planned demolition of the AWS building.

Gross beta analysis is a measure of total radioactivity of beta-emitting radionuclides in a sample. Beta radiation is emitted by many radionuclides and the gross beta measurements are used to identify samples with elevated levels of beta activity that would warrant further analysis.

All of the weekly gross beta activity analysis results were above the MDC. The indicator data trends closely with the control data. The seasonal variability observed in the data is attributable to a factor external to SONGS. The 2020 gross beta data is similar to the gross beta data from the past few years.

The gross beta analysis does not identify specific radionuclides. To identify specific radionuclides, the weekly particulate media is composited quarterly and is analyzed for gamma emitters. During 2020, only naturally occurring radionuclides were identified and no SONGS related radionuclides were detected . Beryllium-? (a naturally occurring radionuclide) was present in all of the quarterly composites.

1-131 is a fission product and can no longer be produced at SONGS with the reactor incapable of operation. As in previous years since SONGS power operation has halted , all samples analyzed for 1-131 were below the MDC. Based on the station no longer being capable of generating 1-131 , the ODCM was revised in November 2020 to discontinue its inclusion in the program . Therefore, sampling and analysis was performed for iodine throughout 2020.

However, it will no longer be included in the AREOR going forward .

Ocean Water Monthly ocean water samples were collected from three indicator locations near each station discharge and from the control location at Newport Beach. The samples were analyzed for naturally occurring and SONGS related gamma-emitting radionuclides, including tritium .

Quarterly composite ocean water samples were analyzed for tritium according to ODCM requirements.

Throughout 2020, only naturally occurring radionuclides were detected in the monthly gamma spectral analyses of ocean water. Monthly ocean water samples were also analyzed for tritium ,

consistent with the CDPH split sample program. During 2020, all the SONGS REMP and the duplicate CPDH tritium ocean water sample results were less than detectable.

Page 127

APPENDIX B 2020 AREOR The data indicate that SONGS had no measurable impact on the environment as measured by ocean water.

Drinking Water In 2020, monthly drinking water samples were collected from one indicator location and from the Oceanside control location. Samples were analyzed for tritium , gross beta , naturally occurring radionuclides, and SONGS related gamma emitting radionuclides. There is no drinking water pathway for liquid effluent at SONGS.

No station related radionuclides were detected in drinking water during 2020. Gross beta activity was identified in some samples, but gamma spectroscopy identified only natural radionuclides. SONGS had no impact on the environment as .measured by drinking water.

Shoreline Sediment (Beach Sand)

Beach sand was collected semiannually in 2020 from three indicator locations and from a control location situated in Newport Beach. After collection , the samples were analyzed for plant related and naturally occurring radionuclides. Only naturally occurring radionuclides were detected in all samples. No plant related radionuclides were reported above the MDC. SONGS had no impact on the environment as measured in beach sand .

Ocean Bottom Sediments Ocean bottom sediments were collected from four indicator locations and the Laguna Beach control location. The samples were analyzed by gamma spectral analysis for naturally occurring and station related radionuclides . Only naturally occurring radionuclides were detected in ocean bottom sediment samples collected during 2020. The Ocean Bottom Sediments analyzed in 2020 did not yield any radionuclides attributable to SONGS.

Marine Species (Flesh)

Species of adult fish , crustacean and mollusks were collected on a semi-annual basis at the SONGS Unit 1 outfall , the SONGS Units 2/3 outfall , and from the Laguna Beach control location. The edible portion of each sample type was analyzed for gamma-emitting station related and naturally occurring radionuclides. The results were subsequently reported to SONGS in terms of wet sample weights. Because results based on a wet sample weight are most useful for calculating doses, the results of sample analyses are summarized in terms of "as received" wet weights. Cs-137 was detected in indicator and control samples above the MDC and below the LLD . This is consistent with the conclusion that the Cs-137 is attributable to sources external to SONGS. Some samples were split with the CDPH and the Cs-137 result (greater than the MDC but less than the LLD) is consistent with results from other marine species samples collected at other west coast locations. Publicly available research from scientific organizations indicates that the presence of Cs-137 in Pacific Ocean sea creatures is attributable to the legacy radioactive contamination from Global weapons testing , Chernobyl ,

and Fukushima (Woods Hole Oceanographic Institution website 3-30-2021). Naturally occurring radionuclides, such as K-40, were also detected in marine species samples collected during 2020, (refer to Table 28 for comparison results) . SONGS had no measurable impact on the environment as measured by this sample medium.

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APPENDIX B 2020 AREOR Local Crops Fleshy and leafy crops were collected semiannually in 2020 from the SONGS garden and from the control location 21 miles SE from SONGS Units 2/3 midpoint. Only naturally occurring radionuclides were identified and no plant related radioactivity was detected during 2020.

SONGS had no measurable impact on local crops.

Soil To determine ifthere is evidence of a build-up of radionuclides in the land near SONGS ,

indicator soil samples were collected from Camp San Onofre, Old Route 101 , Basilone Road and the East Site Boundary (Former Visitors Center). A control sample was obtained from Prince of Peace Abbey in Oceanside. Surface soil was collected from all indicator and control locations at the depth of three inches. The sampling protocol is consistent with the procedure described in HASL-300. Soil sampling is not required by the ODCM.

Soil samples were analyzed for naturally occurring and SONGS related gamma-emitting radionuclides using gamma spectral analysis. The 2020 soil samples showed measurable levels of naturally occurring radionuclides and measurable Cs-137 which is consistent with the decay of legacy Cs-137 in soil attributable to factors external to SONGS (e.g., residual nuclear weapons testing fallout and the Chernobyl accident).

Cs-137 and strontium-90 (Sr-90) were detected in soil profile analyses conducted in previous years. These radionuclides are attributable to the nuclear weapons testing fallout depositing on soil and retention of these radionuclides due to their long half-lives. The presence of Cs-137 in indicator and in control samples at similar levels supports the conclusion that the source of this radionuclide to a factor external to SONGS (fallout deposition). During 2020, SONGS did not have a detectable effect on the environment as measured by soil samples.

Kelp Only one Kelp sample was collected during 2020, at Salt Creek control station . The kelp canopy was absent at all the other locations and was only present at the Salt Creek control location in October 2020. No plant related radionuclides were detected. Kelp sampling is not required by the ODCM .

Correlation of Effluent Concentration to Concentrations in the Environment In accordance with 10 CFR 50 Appendix I, Section IV, B.2, data on measurable levels of radiation and radioactive materials in the environment have been evaluated to determine the relationship between quantities of radioactive material released in effluents and resultant radiation doses to individuals from principal pathways of exposure.

REMP samples, both terrestrial and marine, indicated no accumulation of plant related radioactivity in the environs. Samples with detectable activity were not statistically different from control samples. Plant related radionuclides detected during 2020 were attributed to sources external to SONGS (past nuclear weapons fallout, Chernobyl , and Fukushima) . The regulatory requirement to evaluate the relationship between quantities of radioactive materials released in effluents and the resultant radiation doses to individuals may be summarized by the following conclusion :

Effluent program releases are evaluated annually to determine the receptor(s) with the highest hypothetical dose. The 2020 REMP sample data indicated no accumulation of plant related radionuclides in the environment attributable to SONGS, thereby lending confirmation to the adequacy of the in-plant effluent controls program and dose assessments. Furthermore, the SONGS REMP data are consistent with the conclusion that SONGS has had an insignificant radiological impact on the environment in 2020.

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APPENDIX B 2020 AREOR Statistical Summary of REMP Data for 2020 For the tables below, the numbers in parentheses next to the mean value indicate the number of samples with positive results compared to the total number of samples. The smaller font numbers in parentheses indicate the range of results.

Table 14 -Weekly Airborne Particulates Gross Beta Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Performed* (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Air Filter 0.034 (358/358) Mesa EOF 0.039 (52/52) 0.039 (52/52 )

Inhalation Gross Beta 410 0.0 1 0 (0.012 - 0.090) 0.7 Mi . NNW (0.01 5 - 0.090) (0.01 7 - 0.08 3)

(pCi/m 3 )

NOTES:

a. Though not required by the ODCM , data for optional Air Samplers #7, #10 , #11 are included since valid samples were collected for 2020. Air Sampler #7 was permanently discontinued in November 2020 due to the planned dismantlement of the nearby AWS bu ild ing.

Table 15 -Weekly Radioiodine 1-131 Activity Lower Location with Highest Annual Mean Pathway* Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Performed d (Range) Mean (Range) Mean (Range) Measurements (LLD) b Direction Activated Charcoal 1-131 410 0.07 < MDC c (0/358) All locations < MDC < MDC (0/52) 0 Inhalation (pCi/m 3 )

NOTES:

a This table summarizes the weekly air iodine-13 1 cartridge data above the MDC. lodine-131 has an 8-day half-life. With reactor shutdown , it is no longer a radionuclide attributable to SONGS.

b LLD is the a priori limit as prescribed by the ODCM .

c The Term <MDC as used means that results had no activity above the minimum detectable activity .

d Though not required by the ODCM , data for optional Air Samplers #7, #10, #11 are included since valid samples were collected for 2020. Air Sampler #7 was discontinued in November 2020.

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APPENDIX B 2020 AREOR Table 16 - Quarterly Composite Airborne Particulate Gamma Activity Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Name, Distance and Locations Reported Detection Unit) Performed* (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Air Filter Cs-1 34 32 0.05 < MDC (0/28) < MDC < MDC < MDC (0/4) 0 Inhalation (pCi/m 3 ) Cs- 137 32 0.06 < MDC (0/28) < MDC < MDC < MDC (0/4) 0 NOTES:

a As expected , natural occu rring Be-7 was detected in all quarterly composite air particulate samples . Other naturally occurring radionuclides (such as K-40) were observed in some 2020 quarterly composite air samples . Though not required by the ODCM , data for optional Air Sampler's #7, #10, #1 1 are included since valid samples were collected fo r 2020.

Table 17 - Monthly Ocean Water Activity Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Performed* (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Ba-1 40 48 15 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 Cs- 134 48 15 < MDC(0/36) < MDC < MDC < MDC(0/1 2) 0 Cs-1 37 48 18 < MDC(0/36) < MDC < MDC < MDC(0/1 2) 0 Co-58 48 15 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 Co-60 48 15 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 1-1 31 48 15 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 Ocean Water Fe-59 48 30 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 (pCi/L)

La-140 48 15 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 Mn-54 48 15 < MDC (0/36) < MDC < MDC < MDC(0/1 2) 0 Nb-95 48 15 < MDC(0/36) < MDC < MDC < MDC(0/12) 0 Tritium 48 2000 < MDC (0/36) < MDC < MDC < MDC (0/12) 0 Zn-65 48 30 < MDC (0/36) < MDC < MDC < MDC (0/1 2) 0 Zr-95 48 15 < MDC (0/36) < MDC < MDC < MDC (0/12) 0 NOTES:

a Naturally occurring K-40 was observed in most 2020 ocean water samples .

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APPENDIX B 2020 AREOR Table 18 - Quarterly Ocean Water Tritium Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Name, Distance and Locations Reported Detection Mean (Range)

Unit) Performed (Range) Direction Mean (Range) Measurements (LLD)

Ocean Water Tritium 16 2000 < MDC (0/12) < MDC < MDC < MDC (0/4) 0 (pCi/L)

Table 19 - Monthly Drinking Water Activity Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Name, Distance and Locations Reported Detection (Range) Mean (Range)

Unit) Performed Direction Mean (Range) Measurements (LLD)

Oceanside City Hall (Control) 3.83 (2/12) 3.83 (2/12)

Gross Beta 24 4 < MDC (0/12) 0 (3.82 - 3. 85) (3.82 - 3.85) 15.6 Mi SE Ba-140 24 15 < MDC (0/1 2) < MDC * < MDC < MDC (0/12) 0 Cs-134 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Cs-137 24 18 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Co-58 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Drinking Water Co-60 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 (pCi/L) 1-131 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Fe-59 24 30 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 La-140 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Mn-54 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Nb-95 24 15 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Tritium 24 2000 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Zn-65 24 30 < MDC (0/12) < MDC < MDC < MDC (0/12) 0 Zr-95 24 15 < MDC (0/12) < MDC <MDC < MDC (0/12) 0 Page 132

APPENDIX B 2020 AREOR Table 20 - Semi-annual Shoreline Sediment Gamma Activity (pCi/g)

Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysts Locations Mean Locations Reported Detection Name, Distance and Unit) Perfonned * (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Beach Sand Cs-134 8 0.150 < MDC (0/6) < MDC < MDC < MDC (0/2) 0 Direct Exposure (pCi/g) Cs-137 8 0.180 < MDC (0/6) < MDC < MDC < MDC (0/2) 0 NOTES:

a Naturally occurring radionuclides (K-40 and others) were detected in the 2020 shoreline sediment samples.

Table 21 - Semi-annual Ocean Bottom Sediment Gamma Activity (pCi/g)

Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Perfonned * (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Waterborne Cs-134 10 0.150 < MDC (0/8) < MDC < MDC < MDC (0/2) 0 Ocean Bottom Sediment (pC i/g) Cs-137 10 0.180 < MDC (0/8) < MDC < MDC < MDC (0/2) 0 NOTES:

a Naturally occurring radi onuclides (K-40 and others) were detected in the 2020 ocean bottom sediment samples .

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APPENDIX B 2020 AREOR Table 22 - Sem i-annual Marine Animal Gamma Activity (pCi/g)

Lower Location with Highest Annual Mean Pathway Type and Number AU Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Performed * (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Cs-1 34 24 0.130 < MDC (0/1 6) < MDC < MDC < MDC (0/8) 0 0.0063 (2/1 6) Laguna Beach 0.011 2 (1/8) 0.0112 (1/8)

Cs- 137 24 0.150 0 (0.0052 - 0.0075) 20- 25 Mi NW (0.0112 - 0.011 2) (0.011 2 - 0.011 2)

Non-Mig ratory Co-58 24 0.130 < MDC < MDC < MDC < MDC 0 Marine Animals Co-60 24 0.130 < MDC < MDC < MDC < MDC 0 (pCi/g)

Fe-59 24 0.260 < MDC < MDC < MDC < MDC 0 Mn-54 24 0.130 < MDC < MDC < MDC < MDC 0 Zn-65 24 0.260 < MDC < MDC < MDC < MDC 0 NOTES a Naturally occurring radionuclides (K-40 and others) were detected in the 2020 non-migratory marine an imal samples.

Table 23 - Sem i-annual Local Crops Gamma Activity (pCi/g)

Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Performed* (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Local Crops Cs-134 8 0.06 < MDC (0/4) < MDC < MDC < MDC (0/4) 0 ingestion Cs- 137 8 0.08 < MDC (0/4) < MDC < MDC < MDC (0/4) 0 (pCi/g) 1- 131 8 0.06 < MDC (0/4) < MDC < MDC < MDC (0/4) 0 NOTES:

a Naturally occurring radionuclides (K-40 and others) were observed in the 2020 local crop samples.

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APPENDIX B 2020 AREOR Table 24 -Annual Soil Gamma Activity, 3" Depth (pCi/g)

Lower Location with Highest Annual Mean Pathway _Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Perfonned * (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Soil Cs-134 5 0.150 < MDC < MDC <MDC < MDC 0 Direct Exposure 0.0834 (2/4) Camp San Onofre 0.109 (2/4) 0.0868 (1/1)

(pCi/g) Cs-137 b 5 0.180 0 (0.0576 - 0.109) 2.8 Mi. NE (0.109-0.109) (0.0868 - 0.0868)

NOTES:

a K-40 and other naturally occurring radionuclides were detected in the 2020 REMP soil samples.

b The Cs-137 detected in the control and in two indicator samples at the same level (approximately 0.1 pCi/g). This is due to factors external to SONGS (legacy fallout from nuclear weapons testing and Chernobyl) and are not attributable to SONGS. All indicator sample results have been included in the statistical summary above .

Table 25 -Semi-Annual Kelp Gamma Activity (pCi/g)

Lower Location with Highest Annual Mean Pathway Type and Number All Indicator Control Non-routine Limit of (Measurement of Analysis Locations Mean Locations Reported Detection Name, Distance and Unit) Perfonned b (Range) Mean (Range) Mean (Range) Measurements (LLD) Direction Kelp Ingestion (pCi/g) 1-131 a 1 0.06 NA < MDC < MDC < MDC (0/1) 0 NOTES:

a 1-131 in kelp was not detected above the MDC during 2020.

b Only one kelp sample at the control location (Salt Creek) was available during all of 2020 . No indicator samples were available.

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APPENDIX C 2020 AREOR APPENDIX C.

SUMMARY

OF QUALITY CONTROL PROGRAMS Summary All REMP samples are collected , shipped , and analyzed in accordance with Regulatory Guide 4.15. Marine radiological environmental samples are collected by a vendor, MBC Environmental, per the vendor's Quality Assurance manual. REMP sample analysis is performed by GEL in accordance with GEL's Laboratory Quality Assurance Plan. The CEAL for REMP TLDs was Stanford Dosimetry. The raw data for TLDs was reported as milli-Roentgen/standard quarter and converted to millirem per standard quarter using conversion factors in ANSI N13.37.

Quarterly Duplicate TLDs SONGS deployed a duplicate TLD package, TLD 200, in the same canister as TLD 66. The quarterly dose measured by the duplicate TLD package was statistically equivalent.

Table 26 - 2020 Quarterly Duplicate TLD Data Comparison TLD# 15 TQUARTER 2N°QUARTER 3RDQUARTER 4'QUARTER (mrem) +/- 1 sigma (mrem) +/- 1 sigma (mrem) +/- 1 sigma (mrem) +/- 1 sigma TLD 66 14.05 +/- 0.68 a 14.74 +/- 0.64 14.14 +/- 0.90 16.19 +/- 1.05 TLD 200 13.73 +/- 0.68 14.68 +/- 0.60 14.46 +/- 0.75 15.05 +/- 0.91 NOTES a Data is reported as mrem per standard quarter +/- 1 sigma Annual Duplicate TLDs SONGS deployed an annual duplicate TLD package, TLD 201 , in the same location and canister as REMP TLD 67. The average of four the quarterly TLD 67 exposure results is statistically equal to the annual TLD 201 results for 2020 expressed as mrem/91 days.

Table 27 - 2020 Annual Duplicate TLD Data compared to data from the same canister January 2020 to December 2020 TLD# Average of the quarterly values (mrem/91 days +/- 1 sigma)

TLD 67 17.82 +/- 0.84 TLD 201 17.70 +/- 0.63 Calibration of Air Sampler Volume Meters All REMP air sampler volume meters are calibrated annually using standards referenced to National Institute of Standard and Technology . Calibration of REMP air samplers that are required by the ODCM is verified quarterly to ensure the volume meters remain within limits.

Meters are removed from service if they fail the quarterly test. This is an a posteriori review of the volume meter performance to evaluate method bias and to identify possible outlier analysis results. A bias was not detected in 2020. A review of the air particulate beta results over the course of the year did not indicate a particular bias for any particular sampler. The trends in the beta results over the course of the year were consistent, within the limitations of the gross beta method of analysis.

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APPENDIX C 2020 AREOR lnterlaboratory Cross-Check Program The CDPH participates in a comprehensive radiological environmental split sampling program in conjunction with SONGS. In 2020, the CDPH acquired split samples, collected by an independent third party, from the following SONGS media: atmospheric radioactivity, non-migratory marine animals, kelp, ocean bottom sediments, ocean water gamma emitters, and ocean water tritium. The CDPH also conducts a parallel terrestrial direct radiation (TLD) measurement effort at SONGS, (refer to Appendix H for a discussion of the CDPH TLD data) .

CDPH Atmospheric Radioactivity Gross Beta, 1-131 and quarterly gamma analysis results were substantially similar to the SONGS results for the same media. As expected , both the CDPH Drinking Water and Radiation Laboratory (DWRL) and the SONGS contracted GEL found a gross beta signal above the detection limit. Both labs detected naturally occurring Be-7 in the quarterly composite gamma particulate media samples. Both labs did not detect anthropogenic radionuclides in the split samples with the exception of non-migratory marine animals.

Since ocean water tritium and non-migratory marine animals have the potential for human consumption , their raw data are tabulated below. Fourteen split sample analyses for marine species was conducted. Analysis methodologies are different in that the SONGS contracted laboratory reported a wet weight result, where the CDPH lab reported a dry weight result. The low level Cs-137 was detected in some samples. The variability in the detection of positive results is due to the low activity of the samples, the differences in sample processing , the uncertainty of isotope detection and detection limits at low concentrations. (For a discussion on the presence of Cs-137 in fish , refer to Appendix B.)

Table 28 - Non-migratory marine animals analysis results SONGS data (wet weight) CDPH data (dry weight)

Sample SPLIT SAMPLE Date/ gamma result Gamma result LOCATION MDC MDC Time +I- 2 sigma (pCl/g) +/- uncertainty (pCl/g)

K-40 8.58 +/- 0.526 12-Oct-20 I 1.30 +/- 0.224 7.47E-02 Dry I wet ratio 0.194 6.20E-01 1145 Cs-137 1.34E-2 +/-7.82E-3 Station Discharge 1.48E-3 +/- 5.23E-3 9.23E-03 Dry I wet ratio 0.194 1.93E-02 A

Outfall - Unit 1 K-40 20 .3 +/- 0.917 28-Oct-20 I 4.15 +/- 0.349 5.52E-02 Dry I wet ratio 0.220 5.33E-01 1200 Cs-137 4.22E-2+/- 1.16E-2 9.68E-4 +/- 6.40E-3 1.06E-02 Dry I wet ratio 0.220 2.46E-02 K-40 19.4 +/- 0.988 20-Apr-20 / 2.80 +/- 0.313 9.57E-02 Dry /wet ratio 0.219 4.64E-01 0900 Cs-137 3.67E-2+/- 1.03E-2 4.05E-3 +/- 1.05E-2 9.25E-03 Dry I wet ratio 0.219 2.17E-02 K-40 11.4 +/- 0.748 20-Apr-20 I 2.22 +/- 0.252 7.69E-02 Dry I wet ratio 0.191 7.17E-01 0925 Cs-137 7 .82E-3 +/- 1.21 E-2 5.7 8E-4 +/- 4.81E-3 8.16E-03 Dry I wet ratio 0.191 2.86E-02 B Outfall - Unit 2 K-40 14.1 +/- 0.639 20-Apr-20 / 3.38 +/- 0.320 7.62 E-02 Dry I wet ratio 0.276 3.75E-01 1055 Cs-137 1.87E-2 +/-6.74E-3 3.76E-3 +/- 5.29E-3 9.70E-03 Dry I wet ratio 0.276 1.45E-02 20-Apr-20 / K-40 19.6 +/- 0.852 1115 2.09 +/- 0.136 3.18E-01 Dry I wet ratio 0.239 4.15E-01 20-Apr-20 / Cs-137 (UI) 3.23E-2+/- 8.50E-3 1115 7.48E-3 +/- 6.33E-3 4.99E-03 Dry I wet ratio 0.239 1.78E-02 Page I 37

APPENDIX C 2020 AREOR SONGS data (wet weight) CDPH data (dry weight)

Sample SPLIT SAMPLE Date/ gamma result Gamma result LOCATION MDC MDC Time +/- 2 sigma (pCl/g) +/- uncertainty (pCl/g)

K-40 17.9 +/- 0.959 12-Oct-20 I 3.89 +/- 0.307 5.94E-02 Dry I wet ratio 0.239 7.14E-01 0955 Cs-137 2.53E-2 +/-1.2 2E-2 1.33E-3 +/- 5.25E-3 9.15E-03 Dry I wet ratio 0.239 2.72E-02 K-40 1.47E-1 +/-8.31 E-2 12-Oct-20 I 3.54+/- 0.407 1.08E-01 Dry I wet ratio 0.259 1.97E-01 1000 Cs-137 1.33E-2+/- 6.97E-3

-2 .26E-4 +/- 7.58E-3 1.29E-02 Dry I wet ratio 0.259 1.54E-02 K-40 16.6 +/- 0.920 14-Apr-20 / 3.62 +/- 0.335 7.99E-02 Dry I wet ratio 0.233 5.78E-01 1040 Cs-137 3.02E-2 +/-1 .58E-2 2.77E-3 +/- 7.15E-3 1.13E-02 Dry I wet ratio 0.233 3.51 E-02 K-40 13.8 +/- 0.770 14-Apr-20 / 3.63 +/- 0.235 5.32E-02 Dry I wet ratio 0.243 4.94E-01 1110 Cs-137 1.7 4E-2+/- 1.18E-2

-6 .26E-4 +/- 4.10E-3 6.79E-03 Dry I wet ratio 0.243 2.66E-02 K-40 8.99 +/- 0.708 14-Apr-20 / 1.10+/-0.189 9.31E-02 Dry I wet ratio 0.161 1.00 1315 Cs-137 8.48E-3+/- 1.21 E-2 Laguna Beach - 9.20E-3 +/- 8.27E-3 7.87E-03 Dry I wet ratio 0.161 2.87E-02 C

Control K-40 9.71 +/- 64.7 20-Oct-20 I 1.79+/-0.166 5.78 E-02 Dry I wet ratio 0.676 6.41 E-01 0900 Cs-137 1.51 E-2+/- 1.00E-2 2.27E-3 +/- 3.92E-3 4.46E-03 Dry I wet ratio 0.676 2.48E-02 K-40 15.9 +/- 0.717 20-Oct-20 I 3.41 +/- 0.263 8.18E-02 Dry I wet ratio 0.254 4.07E-01 1100 Cs-137 1.33E-2 +/-9.25E-3

-1 .71E-3 +/- 5.13E-3 7.99E-03 Dry I wet ratio 0.254 2.10E-02 K-40 15.4 +/- 0.827 20-Oct-20 I 3.42 +/- 0.207 3.79E-02 Dry I wet ratio 0.72 4.47E-01 1230 Cs-137 (UI) 2.89E-2 +/-1 .15E-2

5. 70E-3 +/- 5.39E-3 4.80E-03 Dry I wet ratio 0.72 2.48E-02 UI - Uncertain identification for gamma spectroscopy MDC - minimum detectable concentration (SONGS lab)

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APPENDIX C 2020 AREOR Table 29 below shows the results from ocean water tritium samples. All the SONGS and the available CDPH results for 2020 tritium in ocean water were less than detectable. The December 2020 CDPH data was not available.

NOTE: When sample results are analyzed to be lower in activity than the laboratory background result, the result is depicted as a negative value.

Table 29 - CDPH and SONGS split sample tritium in ocean water SONGS bitlum data CDPH tritium data SPLIT SAMPLE LOCATION Sample Date H-3 result H-3 result MDC MDC

+/- 2 sigma (pCI/L) +/. uncertainty (pCI/L)

A Station Discharge 15-Jan-20 -70.1 +/-114 215 -11 .0 +/- 180 307 Outfall - Unit 1 18-Feb-20 -112 +/- 357 619 -115 +/- 128 226 20-Mar-20 81 .9 +/- 313 511 -3.65 +/- 131 226 15-Apr-20 366 +/- 309 461 -13 .3+/- 134 230 21-May-20 234 +/- 323 508 133 +/- 138 230 15-Jun-20 -427 +/- 362 685 -15.3 +/- 137 236 15-Jul-20 -79.8+/-414 709 -57 .3 +/- 136 236 17-Aug-20 -141+/-411 717 -84.9 +/- 135 236 17-Sep-20 59 .1 +/- 356 589 57 .9 +/- 139 236 19-Oct-20 151 +/-307 493 -43.6 +/- 129 224 17-Nov-20 225 +/- 328 515 -24 .7 +/- 130 224 16-Dec-20 -310 +/- 302 558 Data not available (b) -

B Outfall - Unit 2 15-Jan-20 -68 .5 +/- 124 232 -82 .2 +/-.179 307 18-Feb-20 .0933 +/- 351 588 -85 .8 +/- 129 226 20-Mar-20 -13 .5 +/- 283 477 -27.4 +/- 131 226 15-Apr-20 99.3 +/- 289 469 -58 .9 +/- 132 230 21-May-20 152+/-318 512 -20.9 +/- 133 230 15-Jun-20 -282 +/- 387 699 -95.6 +/- 135 236 15-Jul-20 146 +/- 442 715 -59.2 +/- 136 236 17-Aug-20 1.61 +/- 422 707 -27.0 +/- 137 236 17-Sep-20 280 +/- 378 592 15.4 +/- 138 236 19-Oct-20 12.1 +/- 295 494 43.6+/-131 224 17-Nov-20 18.1 +/- 312 521 85.4 +/- 133 224 16-Dec-20 -315 +/- 304 562 Data not available (b) -

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APPENDIX C 2020 AREOR SONGS tritium data CDPH tritium data SPLIT SAMPLE LOCATION Sample Date H-3 resuH H-3 result MDC MDC

+/* 2 sigma (pCI/L) +/- uncertainty (pCI/L)

C Outfall - Unit 3 15-Jan-20 88 .6 +/- 154 231 98.6 +/- 182 307 18-Feb-20 -240 +/- 323 585 -51 .1 +/- 130 226 20-Mar-20 16.1 +/- 293 489 -29.2 +/- 131 226 15-Apr-20 82 .2 +/- 280 456 38.0 +/- 135 230 21-May-20 167 +/- 322 517 -53 .2 +/- 133 230 15-Jun-20 -92 .1 +/- 430 737 -24 .8 +/- 137 236 15-Jul-20 135 +/- 431 698 -112.8 +/- 134 236 17-Aug-20 -154 +/- 394 691 -81.0 +/-135 236 17-Sep-20 - 182 +/- 325 574 -84.9 +/- 135 236 19-Oct-20 318 +/- 321 493 17.1+/-131 224 17-Nov-20 12.7 +/- 315 527 24.7 +/- 131 224 16-Dec-20 229 +/- 346 545 Data not available (b) -

D Newport Beach (Control) 15-Jan-20 255 +/- 334 525 159 +/- 183 307 18-Feb-20 -208 +/- 330 590 40.2 +/- 132 226 20-Mar-20 216 +/- 312 488 -55 .6 (a) 226 15-Apr-20 200 +/- 298 468 28.5 +/- 135 230 21-May-20 -157 +/- 295 520 38.0 +/- 135 230 15-Jun-20 -325 +/- 379 693 -89.8 +/- 135 236 15-Jul-20 98 .7+/- 414 677 17.2 +/- 138 236 17-Aug-20 -73 .5 +/- 398 682 -3 .86 +/- 137 236 17-Sep-20 -171 +/- 342 601 3.86 +/- 137 236 19-Oct-20 164 +/- 307 490 64.5 +/- 132 224 17-Nov-20 325 +/- 330 504 30.4+/-131 224 16-Dec-20 -239 +/- 314 566 Data not available (b) -

Note that the EPA drinking water maximum perm1ss1ble tritium actIvIty Is 20 ,000 pC1 / liter. Both labs only detected naturally occurring radionuclides in ocean bottom sediments and ocean water. No plants related radionuclides were reported above the MDC.

Notes:

(a) The uncertainty for this sample is not available (b) The December 2020 CDPH data is not available per the CDPH Page 140

APPENDIX C 2020 AREOR GEL participates in three independent cross check programs. GEL's QA programs consists of these testing vendors: Eckert & Ziegler Analytics, U.S. DOE MAPEP, and ERA's MARO Proficiency Testing Program. Non-agreement results were resolved in accordance with GEL's corrective action program.

In 2020, the environmental TLDs, routine quality control (QC) testing was performed for the types of dosimeters issued by the Environmental Dosimetry Company (EDC) . During 2020, 100% (72/72) of individual dosimeters evaluated against the EDC internal performance acceptance criteria (high-energy photons only) met the criterion for accuracy and 100% (72/72) met the criterion for precision.

The GEL and Stanford Dosimetry performance meets the criteria described in Reg . Guide 4.15 and ANSI/HPS N13.37-2014.

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APPENDIX D 2020 AREOR APPENDIX D. COMPARISON OF 2020 REMP DATA TO HISTORICAL DATA Comparison of 2020 REMP data to Historical Data and Analysis of Trends Unit 1 achieved criticality on June 14, 1967 and was permanently retired from service on November 30 , 1992. Unit 2 attained initial criticality on July 26, 1982 and Unit 3 on August 29, 1983.

A variety of environmental samples were analyzed and the analytical results (January 1, 1979 to July 31 , 1982) were compared with the 2020 REMP data obtained for SONGS Units 2/3.

The following media were evaluated and compared with the operational data of SONGS Units 1, 2 and 3:

External Radiation

Air Particulates

Radioiodine

Ocean Water

Shoreline Sediment (Sand)

Ocean Bottom Sediments

Marine Species

Local Crops

Soil

Kelp

Drinking Water The measurements obtained from the SONGS Unit 1 operational Radiological Environmental Monitoring Program (REMP) during the period from January 1979 to July 1982 are used as the pre-operational baseline for SONGS Units 2/3. This is in accordance with San Onofre Units 2/3, Environmental Report, Operating License Stage, Appendix 6A, Pre-operational Radiological Environmental Monitoring , May 31 , 1978. Comparisons of pre-operational data to 2020 REMP data are possible for each of the following exposure pathways: (1) direct radiation , (2) air particulates (inhalation) , and (3) ocean water (marine pathway for ingestion) . Comparisons can also be made between pre-operational and 2020 REMP data for ocean bottom sediment data to ascertain if there has been any significant increase in radioactivity in ocean bottom sediments near the SONGS Units 2/3 outfalls.

Currently the pre-operational data are higher than the 2020 REMP data. The decrease in radioactivity is due primarily to the cessation of atmospheric nuclear weapons testing and to the decay of fallout radionuclides. There is a close correlation between indicator and control data over several decades. There are no indications of adverse effects from SONGS on the environment.

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APPENDIX D 2020 AREOR Direct Radiation The direct radiation measurements for the SONGS REMP were made by TLDs on a quarterly collection cycle at 49 locations in 2020. (See Appendix I for ISFSI TLD data). The TLDs were located at inner and outer ring locations as specified by the ODCM. During the pre-operational period from January 1979 to July 31 , 1982, the indicator stations ranged from 16. 1 to 46.6 mrem. The preoperational indicator average was 25.3 mrem. The pre-operational control range was 19.3 to 30 .1 and the control mean was 23.1 mrem . During the 2020 REMP year for Units 2/3, the SONGS REMP TLD data was processed in accordance with ANSI/HPS N13.37-2014.

Accordingly, the data from individual REMP TLD locations are evaluated against the baseline for each location . The individual REMP TLD locations are not compared with distant control locations for evaluation per the current regulatory guidance, Reg . Guide 4.13 Revision 2, 2019 (Environmental Dosimetry - Performance Specifications, Testing , and Data Analysis) . Refer to Appendix B for a detailed discussion of the REMP TLD data evaluation process.

Factors such as meteorology, local geology, the fallout from atmospheric nuclear weapons testing , and seasonal fluctuations account for the variability in the data as observed during the preoperational period for each location . The decrease in radiation levels at all TLD sample locations is attributable to the curtailment of the atmospheric nuclear weapons testing , and the continued decay of the manmade background from fallout from past nuclear weapons tests.

Simultaneous variation in the radiation levels at both the control and indicator locations shows that the variations are due to factors external to SONGS. Outside the EAB there were no measurable levels of increased direct radiation associated with SONGS as measured by TLDs.

Airborne Particulates From January 1979 through December 1982 (considered to be the pre-operational period for SONGS Units 2/3), there was a noticeably higher gross beta activity in air at all sample locations. This period extends from the fourth quarter of 1980 through the fourth quarter of 1981 . These higher activity levels were attributable to the Chinese atmospheric nuclear weapons test conducted on October 15, 1980.

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APPENDIX D 2020 AREOR 0 .6 l*a'IOJI kof'I hines~

N..c eur Weripora I<Sing pl 1977 0.5 0.4 M

<3 0.3 0..

0.2 0 .1 0

~ ~ ~

- -HB Control - - oside Control - SLR Control San aemente - State Beach Park Bluff Figure 9 - Monthly Average Airborne Particulate Gross Beta Preoperational and Operational Data for Units 2 and 3, (1976 - Jan 2020)

For 2020, the maximum average annual airborne particulate gross beta result was 0.039 pCi/m 3 . This result is in line with recent history.

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APPENDIX D 2020 AREOR Radioiodine Most of the preoperational data for 1-131 level was below the detection limit. All the 2020 REMP 1-131 data were below the detection limit. This is expected , as the shutdown and defueled SONGS is no longer producing 1-131 , and all previously produced 1-131 has decayed away.

SONGS had no effect on the environment as measured by the radioiodine cartridge data in 2020.

Ocean Water Monthly ocean water samples were collected near each of the Station discharge outfalls , and from the Newport Beach control location. The ocean water samples are analyzed for naturally occurring and station-related gamma-emitting radionuclides. Samples were composited quarterly and analyzed for tritium.

During the pre-operational period , naturally occurring potassium-40 was detected in each of the samples collected from both indicator and control locations. Other gamma-emitting radionuclides were detected in only one ocean water sample. In May 1980, Co-58, Co-60, Cs-134 , and Cs-137 were detected in an ocean water sample collected from the SONGS Unit 1 outfall. Concentrations of the radionuclides in this sample were 11 , 6, 380, and 430 pCi/I respectively. Tritium was also detected in two of the ocean water samples collected in May 1980 from the SONGS Unit 2 outfall and in and from the Newport Beach control location.

No plant related radionuclides were detected in ocean water during 2020. SONGS had no impact on the environment as measured by this exposure pathway in 2020.

Drinking Water Due to its location near the beach , there is no drinking water pathway for SONGS.

Nonetheless, drinking water samples from Oceanside and Camp Pendleton were collected and analyzed. No plant related radionuclides were detected in drinking water in 2020. Gross beta activity (from natural radionuclides) was detected during 2020 and during the pre-operational periods at both the indicator and the control locations. No trends have been noted. SONGS had no impact on the environment as measured by this exposure pathway.

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APPENDIX D 2020 AREOR Shoreline Sediments (Sand)

Beach sand is collected semiannually from three indicator locations and from a control location situated at Newport Beach. The samples are analyzed for naturally occurring and plant related radionuclides.

To assess the impact of SONGS operations on this environmental medium, pre-operational data were compared to the 2020 REMP data (refer to Table 30). The radionuclide detected in shoreline sediment in the preoperational time frame was Cs-137 with a range of 0.012 to 0.022 pCi/g , averaging 0.019 in five sediment samples. One control sample with a Cs-137 activity of 0.032 pCi/g was observed in July 1979. The presence of Cs-137 in both control and indicator locations during the preoperational period leads to the conclusion that the activity is external to SONGS and is most likely attributable to atmospheric nuclear weapons testing . No SONGS related radionuclides were detected in shoreline sediment during 2020. SONGS had no impact on the environment as measured by this exposure pathway in 2020.

Table 30 - Shoreline Sediment Concentration INDICATOR CONTROL Radionuclide Period* Range b Average Range Average (pCi/g, wet) (pCi/g, wet) (pCl/g, wet) (pCi/g, wet)

Cs-137 PreOp 0.012 - 0.022 0.019 < LLD - 0.032 < LLD 2020 C < LLD < LLD < LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionuclides 2020 C < LLD < LLD < LLD < LLD NOTES:

a Preoperational period is January 1979 - July 1982.

b LLD for operational data are listed in Appendix B c During 2020, all station related radionuclides from all sample locations were < LLD Page I 46

APPENDIX D 2020 AREOR Ocean Bottom Sediments In 2020 and during the pre-operational periods, representative samples of ocean bottom sediments were collected semiannually from each of the Station discharge outfalls and from a control station in Laguna Beach. The samples were analyzed for naturally occurring and SONGS related radionuclides.

Table 31 compares historical information versus 2020 sample results. During the pre-operational period , manganese-54 (Mn-54) was detected in 5 of the 28 samples. Cobalt-58 (Co-58) was detected in nine samples . Cobalt-60 (Co-60) was measured in 15 of the 28 samples. Cs-137 was also detected in 16 of the 28 samples. The concentrations of Cs-137 in the samples ranged from 0.014 to 0.090 pCi/g , averaging 0.039 pCi/g. Cerium-144 (Ce-144) was found in two samples.

The concentration of station related radionuclides in all ocean bottom sediment samples analyzed in 2020 was below the MDC. SONGS had no impact on the environment as measured by this exposure pathway in 2020.

Table 31 - Ocean Bottom Sediment Concentration INDICATOR CONTROL Rangeb Average b Range Average Radionuclide Period*

(pCi/g, wet) (pCi/g, wet) (pCl/g, wet) (pCi/g, wet)

Mn-54 PreOp 0.015 - 0.49 0.129 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Co-58 PreOp 0.013 -1 .160 0.199 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Co-60 PreOp 0.014 - 8.100 0.788 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Ag-110m PreOp < LLD - 0.020 < LLD < LLD < LLD 2020 < LLD < LLD < LLD < LLD Cs-137 PreOp 0.014 - 0.090 0.039 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Ce-144 PreOp 0.060 - 0.260 0.160 < LLD < LLD 2020 < LLD < LLD < LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionuclides 2020 < LLD < LLD < LLD < LLD NOTES:

a Preoperational period is January 1979 - July 1982.

b LLD for operational data are listed in Appendi x B Page I 47

APPENDIX D 2020 AREOR Marine Species (Flesh)

Non-migratory marine species are collected semi-annually near SONGS. Non-migratory marine animals are collected near the SONGS outfalls and from Laguna Beach and analyzed for gamma-emitting radionuclides as specified in the ODCM . The results are subsequently reported as pCi/g , wet weight.

Results for several marine species for both 2020 and for the pre-operational period for Units 2/3 are summarized in Table 32. The marine species used for purposes of comparison include: two species of fish , Bay Mussel (a mollusk), and Spiny Lobster (a crustacean) . Radionuclides analyzed , but not included in Table 32, were below the lower limits of detection for both the pre-operational and operational periods.

During 2020 several samples (both indicator and control) had low level Cs-137 activity> MDC and < LLD. This is consistent with other Pacific Ocean marine organism samples at other locations and is consistent with the levels of Cs-137 in marine samples that may be attributable to the ocean water discharges from Fukushima. The data indicate no accumulation trends attributable to SONGS. SONGS had an insignificant impact on the environment as measured by this exposure pathway in 2020.

Table 32 - Marine Species Concentration INDICATOR CONTROL Range Average Range Average Radionuclide Period* (pCi/g, wet) (pCi/g, wet) (pCl/g, wet) (pCi/g, wet)

Fish Sample 1 Flesh d Co-58 PreOp 0.016 - 0.030 0.023 < LLD < LLD 2020 b < LLD < LLD < LLD < LLD Co-60 PreOp 0.005 - 0.044 0.017 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Ag-110m PreOp < LLD - 0.004 < LLD < LLD < LLD 2020 < LLD < LLD < LLD < LLD Cs-137 PreOp 0.004 - 0.018 0.007 0.005 - 0.012 0.007 2020 < LLD < LLD <LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionuclides 2020 < LLD < LLD < LLD < LLD Fish Sample 2 Flesh d Co-58 PreOp 0.009-0.011 0.010 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Co-60 PreOp 0.004-0.045 0.017 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Ag-110m PreOp 0.002-0.009 0.006 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Cs-137 PreOp 0.003-0.015 0.008 0.004-0.014 0.009 2020 < LLD <LLD < LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionuclides 2020 < LLD < LLD < LLD < LLD Page 148

APPENDIX D 2020 AREOR INDICATOR CONTROL Range Average Range Average Radionuclide Period* (pCi/g, wet) (pCi/g, wet) (pCi/g, wet) (pCl/g, wet)

Mussel Flesh (Bay or California) d Mn-54 PreOp 0.009 - 0.025 0.017 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Co-58 PreOp 0.008 - 0.080 0.028 -- --

2020 < LLD < LLD < LLD < LLD Co-60 PreOp 0.005 - 0.400 0.077 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Cs-137 PreOp 0.003 - 0.006 0.004 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Ru-103 PreOp < LLD - 0.045 < LLD < LLD < LLD 2020 < LLD < LLD < LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD Radionuclides 2020 C < LLD < LLD < LLD < LLD Spiny Lobster Flesh (Bay or California) d Co-58 PreOp 0.007 - 0.270 0.086 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Co-60 PreOp 0.014 - 0.210 0.060 < LLD < LLD 2020 < LLD < LLD < LLD < LLD Cs-137 PreOp 0.005 - 0.011 0.008 0.040 - 0.015 0.008 2020 < LLD < LLD < LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionucl ides 2020 C < LLD < LLD < LLD < LLD NOTES:

a Preoperational period is January 1979 - July 1982.

b LLD for the 2020 data are listed in Appendix B c During 2020 , all station related radionuclides from all sample locations were < LLD d Samples collected in 2020 include crustacea, mollusks, and two adult species of fish at each location and collection evolution.

Local Crops In the preoperational period of January 1979 through July 1982, Sr-90 was detected in the control samples of kale , parsley, and squash . Naturally occurring K-40 was detected in cucumber, kale, and tomato samples from the indicator and control locations. Ce-144 and Zr-95 were detected in one sample of parsley at the control location at concentrations of 0.12 and 0.09 pCi/g, wet weight respectively.

During 2020, only natural radionuclides were identified in local crops , at both the indicator and control locations. SONGS had no impact on the environment as measured by this exposure pathway in 2020.

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APPENDIX D 2020 AREOR Soil A comparison of operational and preoperational data does not reveal any accumulation pattern of SONGS related isotopes in soil (refer to Table 33). The intermittent detection of Cs-137 in both indicator and control locations is due to residual fallout from atmospheric nuclear weapons testing. SONGS had no impact on the environment as measured by this exposure pathway in 2020.

Table 33 - Soil Concentration Indicator Control Range Average Range Average Radionuclide Period (pCl/g) (pCl/g) (pCl/g) (pCi/g)

Sr-90 PreOp 0.02 - 0.08 0.044 < LLD - 0.03 < LLD 2020 N/A N/A N/A N/A Cs-137 PreOp 0.02 - 0.20 0.096 < LLD - 0.06 < 0.10 2020 <LLD <LLD <LLD <LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionuclides 2020 < LLD < LLD < LLD < LLD Page I 50

APPENDIX D 2020 AREOR Kelp Kelp is normally collected semiannually from three indicator locations and from a control location situated at Salt Creek. The samples are analyzed by gamma-spectral analysis for naturally occurring and SONGS related radionuclides.

To assess the impact of SONGS on kelp, pre-operational data were compared to 2020 REMP data in Table 34. Radionuclides detected during the pre-operational period for SONGS include Mn-54, Co-60 , Zr-95, 1-131 , and Cs-137.

Although 1-131 activity has been detected in kelp since 1977, there is no evidence that the concentrations of 1-131 are a result of operations at SONGS. The presence of 1-131 in kelp is due to the sewer release of medical administrations of radioisotopes, since it has been detected consistently in control as well as indicator locations. Since 1988, the concentration of 1-131 ,

when detected, has typically been highest at the control locations. There is correlation between indicator and control sample locations over an extended period of time.

During the 2020 REMP only one kelp sample, the October Salt Creek control location , was available. The kelp canopy was missing from all other locations in 2020. No SONGS related radionuclides were detected. Since there is no longer a viable production mechanism for 1-131 at SONGS, the detection of 1-131 in kelp is due to factors external to SONGS. SONGS had no impact on the environment as measured by this exposure pathway in 2020.

Table 34 - Kelp Concentration Indicator Control Range Average Range Average Radionuclide Period (pCi/g) (pCi/g) (pCi/g) (pCi/g)

Mn-54 PreOp < LLD - 0.005 < LLD < LLD < LLD 2020 N/A N/A < LLD < LLD Co-60 PreOp 0.006 - 0.009 0.008 < LLD < LLD 2020 N/A N/A < LLD < LLD Zr(Nb)-95 PreOp 0.014 - 0.090 0.046 0.018 - 0.053 0.036 2020 N/A N/A < LLD < LLD 1-131 PreOp 0.006 - 0.024 0.013 0.008 - 0.030 0.014 2020 N/A N/A < LLD < LLD Cs-137 PreOp 0.004 - 0.071 0.027 < LLD < LLD 2020 N/A N/A < LLD < LLD All other SONGS PreOp < LLD < LLD < LLD < LLD radionuclides 2020 N/A N/A < LLD < LLD Page I 51

APPENDIX E 2020 AREOR APPENDIX E. DEVIATIONS FROM ODCM SAMPLING REQUIREMENTS IN 2020 DEVIATIONS FROM ODCM SAMPLING REQUIREMENTS Deviations from the ODCM sampling requirements are identified below in accordance with section 5.0 of the ODCM . During 2020, the ODCM specified a priori LLD was achieved for all REMP samples. Deviations from the ODCM were associated with external factors not within the control of REMP personnel such as limited availability of marine samples at the locations specified in the ODCM , external power outages, and other unavoidable deviations. The 2020 ODCM deviations had no meaningful impact on the REMP data and does not compromise the validity of the reported conclusions.

Direct Radiation Thermoluminescent Dosimeters (TLDs)

1. TLD 78 was off station for the second , third , and fourth quarter 2020 due to construction activities.

2. TLDs 55 and 56 were off station during the fourth quarter of 2020 due to vandalism .

Air Sampling At SONGS , the ODCM requires a total of four Indicator stations and one Control station.

Downtime for each air sampler in 2020 was due to weekly sample collection , quarterly calibrator flow comparison checks , scheduled air sampler motor assembly / calibrator change-outs, and preventative air sampler motor assembly change-outs which was conducted if a motor assembly was observed to show signs of degraded performance (excessive bearing noise, vane erosion ,

flow decline, etc.). During 2020, there were no avoidable deviations from the ODCM .

Routine unavoidable air sampler down time (per sampler) includes the following :

Weekly sample collection events: 0.5 minutes (approx.) x 52 = 26 minutes Quarterly calibrator comparison check: 5 minutes (approx.) x 4 = 20 minutes Other air sampler maintenance: 10 minutes (approx.)

Other down times in excess of one hour are addressed below for each ODCM required air sampler.

1) Air Sampler #12 (Former SONGS Evaporation Pond) had 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months of down time during the collection period ending 02-11-2020 attributed to an external power outage .

2) Air Sampler #9 (State Beach Park) was out of service for an estimated 75 hours8.680556e-4 days 0.0208 hours 1.240079e-4 weeks 2.85375e-5 months due to a motor failure during the collection period ending 3-24-2020.

3) Air Sampler #9 (State Beach Park) was out of service for 72.1 hours1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months due to an external power outage during the collection period ending 5-5-2020. The power outage continued into the next collection period ending 5-12-2020 causing an additional 33.6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months of down time during the collection period ending 5-12-2020.

4) Air Sampler #16 (San Luis Rey Substation (control)) was out of service for 12.2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months during the collection period ending 6-23-2020 due to an external power outage.

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APPENDIX E 2020 AREOR

5) Air Sampler #9 (State Beach Park) was out of service for 5.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months due to an external power outage during the collection period ending 8-4-2020.

6) Air Sampler #12 (Former SONGS Evaporation Pond) was out of service for 5.8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months due to an external power outage during the collection period ending 8-4-2020.

7) Air Sampler #13 (Camp Pendleton East) was out of service for 11.4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months on during the collection period ending 9-1-2020 due to an external power outage.

8) Air Sampler #16 (San Luis Rey Substation (control)) was out of service for 1.9 hours1.041667e-4 days 0.0025 hours 1.488095e-5 weeks 3.4245e-6 months during the collection period ending 10-6-2020 due to an external power outage.

Ocean Water Sampling No deviations were observed .

Drinking Water No deviations were observed .

Shoreline Sediments No deviations were observed.

Ocean Bottom Sediments No deviations were observed .

Marine Species (Flesh)

No deviations were observed.

Local Crops No deviations were observed.

Soil No deviations were observed .

Kelp Kelp samples are not required by Section 5.1 of the ODCM . Normally, four kelp beds are collected twice a year for a total of eight kelp samples. Only one sample was available during 2020. The Kelp canopy was absent at all locations for the rest of the year. For the radionuclide of interest in kelp (l-131) , there is no credible source from the decommissioning activities at SONGS . This did not constitute a deviation from the ODCM.

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APPENDIX F 2020 AREOR APPENDIX F. ERRATA TO PREVIOUS AREORs The 2019 AREOR reported nine (9) as the total number of local crop samples collected during 2019 on page 38 of the report. The actual number of local crop samples collected was eight (8) as reported on page 25 of the 2019 AREOR .

The total number of indicator ocean bottom sediment samples collected every six months at SONGS was reported to be three (3) on page 31 of the 2019 AREOR . The actual number of indicator ocean bottom sediment samples was four (4).

The dose measured at TLD 59 was incorrectly reported to be attributable to the operation of the ISFSI in the 2019 AREOR. A review of the local conditions at TLD 59 indicate that the measured dose is attributable to a local variation in the baseline signal. The average baseline for the SONGS area was estimated to be 15.8 mrem per standard quarter based on the measured baselines at locations near SONGS. However, the baseline is not uniform throughout the SONGS footprint. The baseline at each specific location within the EAB could only have been precisely measured before SONGS was constructed . The technology for TLDs did not exist at that time.

On page 51 of the 2019 AREOR , the note below Figure 11 reported the maximum 2019 average airborne particulate gross beta result as 0.036 pCi/m 3

This value was stated to be the maximum monthly average but should have stated that it was the maximum annual average.

These errors do not change the conclusion of the 2019 AREOR.

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APPENDIX G 2020 AREOR APPENDIX G. CDPH CO-LOCATED TLDs DATA FROM THE CDPH TLDs CO-LOCATED WITH SONGS REMP TLDs DURING 2020 CDPH maintains a TLD program in the environs of SONGS. Per CDPH request, the 2020 exposure results from the CDPH dosimeters are reported in the table below. The Location Numbers refer to the current SONGS Decomm issioning Solutions (SOS) alphanumeric location identifier and the current CDPH location number. The first quarter TLDs were left on-station until the end of the second quarter due to the limitations imposed as a result of the COVID epidemic. The dose was divided equally between the first and second quarter 2020.

Table 35 - 2020 State of California Data from the CDPH TLD program (mrem/standard quarter) 1 st 2nd 3rd 4th Location Numbers Location Name Qtr. Qtr. Qtr. Qtr.

SDS-1 , CDPH #2 City of San Clemente 20.5 20.5 25 34 Former US Coast Guard Station -

SDS-22 , CDPH #4 M M 25 30 San Mateo Point SDS-34 , CDPH #5 San Onofre Elementary School 21 21 21 30 Bluff (Adjacent to PIC #1) (San SDS-10 , CDPH #6 21 .5 21 .5 25 30 Onofre Surfing Beach)

SDS-16 , CDPH #7 East Southeast Site Boundary 17.5 17.5 20 28 SDS-2 , CDPH #8 Camp San Mateo 21 .5 21.5 23 34 SDS-3 , CDPH #9 Camp San Onofre 20.5 20.5 24 28 Old El Camino Rea l (Old Highway SDS-6, CDPH #10 16 16 17 20 101 ) (ESE)

SDS-50, CDPH #13 Oceanside Fire Station 20.5 20.5 20 30 M=CDPH data is not available from CDPH #4 for the 1st and 2nd quarters 2020 since this TLD was not on station when the TLDs were collected in July 2020.

The CDPH TLD program does not conform to the same environmental dosimeter standard Reg .

Guide 4.13 (ANSI N13.37-2014) used to generate direct radiation data for the SONGS REMP TLD program . CDPH lab reports results in different units of measurement and is therefore not technically equivalent to the SONGS TLD data set. The different methodologies and the different units of measurement make it unsuitable to directly compare individual REMP data to the corresponding individual CDPH TLD data. However, the CDPH results are consistent with conclusion that beyond the EAB there is no detectable direct radiation that is attributable to SONGS .

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APPENDIX H 2020 AREOR APPENDIX H. ISFSI TLD DA TA Summary Per 10 CFR 72 .126, SONGS implemented an area monitoring TLD program in the vicinity of the ISFSI.

An evaluation of the entire REMP TLD database yielded an estimated background exposure rate of approximately 15.8 mrem/std. quarter (91 days) . However, some local variability within the SONGS EAB is known to exist and cannot be precisely know at every location within the SONGS. This value would need to have been measured before SONGS was constructed and TLD technology did not exist at that time. Therefore, a comparison of pre-operational data to the 2020 data needs to be considered in conjunction with a comparison of ISFSI TLD data and the estimated baseline background exposure rate within the EAB.

Environmental exposure rates are variable and small changes in TLD location can measurably change the data. SONGS REMP TLD data show an environmental seasonal variability that is not related to any activities at SONGS. The ISFSI TLD data gathered to date follow a similar seasonal variability .

The measured exposure rate for the ISFSI TLDs close to the ISFSI is consistent with the exposure rate expected from known radiological work activities. The elevated exposure rate from TLDs 301 , 302 , 303, 304 , and 326 in 2020 is primarily due to the movement and storage of used fuel at the ISFSI during the year.

Publicly accessible REMP TLDs include SCE-55, SCE-56 and SCE-57. In 2020, ISFSI TLDs SCE-55 (San Onofre State Beach U1West), SCE-56 (located next to SCE-55) , and SCE-59 (SONGS Meteorological Tower) , recorded measurable annual facility doses. The occupancy adjusted dose to a member of the general public is less than one (1) mrem per year. This was reported in the 2020 Annual Radioactive Effluent Release Report.

I Starting in the fourth quarter 2010, neutron dosimeters were placed in ISFSI TLD canisters 311 ,

324, 325, and 326. Beginning in the fourth quarter of 2016, neutron TLDs were co-located with locations SCE-339 through SCE-343. The neutron TLDs were added to obtain neutron information prior to the off load of spent fuel from Units 2 and 3.

The 2020 neutron TLDs identified measurable levels of neutron radiation from movement of spent fuel to dry storage. A dose equivalent conversion factor for the TLD neutron signal based on a similar ISFSI facility at another site was adopted to estimate the neutron dose rate at SONGS. It is being applied to the SONGS TLD results only to provide an estimate of the neutron dose equivalent being measured. The neutron dose has been included in the quarterly results for these locations in Table 36. The results from all locations at the fence around the ISFSI pad show that the dose to a member of the public, when adjusted for occupancy, would be less than one (1) mrem per year.

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APPENDIX H 2020 AREOR Table 36 - 2020 ISFSI TLD Data Annual Annual Qtr. 2020 Quarterly Results Baseline Adjusted Quarterly Results TLD (mrem) Annual Dose Facility Public Location

Baseline (mrem)'

(SCE-##) (mrem) Dose Doseb (mrem)

(mrem) (mrem) 1 2 3 4 1 2 3 4 301 15.8 20.4 19.2 18.3 19.7 ND ND ND ND 77.7 14.6 -

302 15.8 27.0 24.3 24.2 23.3 11.3 8.5 8.4 7.5 98.7 35.7 -

303 15.8 24.1 23.3 22.7 22.6 8.4 7.6 6.9 6.9 92.8 29.7 -

304 15.8 22.5 21.7 20.3 20.0 6.7 5.9 ND ND 84.5 21.4 -

307 15.8 20.6 20.4 18.5 20.1 ND ND ND ND 79.6 16.5 -

308 15.8 19.2 17.7 18.1 20.2 ND ND ND ND 75.2 12.2 -

309 15.8 19.9 19.9 19.4 20.2 ND ND ND ND 79.3 16.2 -

310 15.8 20.8 20.5 20.3 20.8 5.0 ND ND 5.0 82.3 19.3 -

311 ISFSl-01 c 15.8 19.9 20.6 20.6 19.8 ND ND ND ND 81.0 18.0 -

312 15.8 16.2 15.9 15.9 15.7 ND ND ND ND 63.8 ND -

314 15.8 20.9 20.0 20.4 20.2 5.2 ND ND ND 81.5 18.4 -

315 15.8 21.3 19.2 18.6 18.8 5.5 ND ND ND 77.9 14.9 -

316 15.8 16.6 15.9 15.8 16.8 ND ND ND ND 65.2 ND -

317 15.8 19.4 16.7 16.2 17.8 ND ND ND ND 70.0 ND -

318° 15.8 18.6 19.3 18.8 19.2 ND ND ND ND 75.9 12.8 -

319° 15.8 18.6 19.1 18.3 20.1 ND ND ND ND 76.1 13.0 -

320° 15.8 19.2 18.4 18.3 19.1 ND ND ND ND 74.9 11.9 -

321" 15.8 19.2 19.5 18.7 19.9 ND ND ND ND 77.4 14.3 -

322 Discontinued 15.8 -- -- -- -- - - - - - - -

323 Discontinued 15.8 -- -- -- -- - - - - - - -

324 Discontinued 15.8 -- -- -- -- - - - - - - -

325 Discontinued 15.8 -- -- -- -- - - - - - - -

326 ISFSl-02 c 15.8 21.4 22.5 22.3 24.5 5.6 6.7 6.5 8.8 90.7 27.7 -

327 Discontinued 15.8 -- -- -- -- - - - - - - -

328 Discontinued 15.8 -- -- -- -- - - - - - - -

339 ISFSl-08 c 15.8 26.5 26.4 24.2 24.4 10.7 10.6 8.5 8.7 101.5 38.4 -

340 ISFSl-09 c 15.8 23.5 23.1 21.6 22.5 7.7 7.3 5.8 6.7 90.6 27.6 -

341 ISFSl-10 c 15.8 23.9 23.7 24.0 24.3 8.2 7.9 8.2 8.5 95.9 32.9 -

342 ISFSl-11 c 15.8 26.6 26.4 27.5 27.3 10.9 10.6 11.7 11.5 107.8 44.7 -

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APPENDIX H 2020 AREOR Qtr. 2020 Quarterly Results Baseline Adjusted Quarterly Results Annual Annual TLD (mrem) Annual Dose Facility Public Location

Baseline (mrem)'

(SCE-##) (mrem) Dose Doseb (mrem)

(mrem) (mrem) 1 2 3 4 1 2 3 4 343 ISFSl-12 c 15.8 22.2 20.8 23.7 23.6 6.4 5.0 7.9 7.8 90.2 27.2 -

344 15.8 21.9 20.3 20.0 21.2 6.1 ND ND 5.4 83.4 20.4 -

San Onofre State 55 de Beach (U 1 West) 15.8 5.2 6.8 5.9 - 86.9 N/A <1 ISFSl-07 c 21.0 22.5 21.7 --

San Onofre State 56 d Beach (U 1 West) 15.8 19.2 18.5 18.7 -- ND ND ND - 75.2 N/A <1 San Onofre State 57 d 15.8 ND ND ND ND 70.8 Beach (Unit 2) 18.3 17.2 17.6 17.7 ND <1 SONGS 59 15.8 ND ND ND ND 79.5 Meteorological Tower 20.1 20.0 19.4 19.9 16.4 -

Notes:

a ISFSI TLDs (SCE-301 through SCE-344) are placed around the ISFSI pad , and not in locations accessible to the general public. TLD 59 is in an area that is not accessible to the general public. A public dose to these locations is not applicable.

b Public dose is not applicable for those TLDs that are not accessible to the general public.

c Station has a collocated neutron dosimeter package. The neutron dose is estimated using a neutron signal conversion factor measured at a similar ISFSI installation (HPSTID 08-015).

d These TLDs are publicly accessible. The public dose is based on an estimated occupancy of 300 hours0.00347 days 0.0833 hours 4.960317e-4 weeks 1.1415e-4 months per year.

e For TLD 55 the estimated neutron dose contributed to the total measured dose in 2020.

f For locations with a co-located neutron dosimetry package the estimated neutron dose (if any) is included in the reported dose.

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APPENDIX H 2020 AREOR ISFSI TLDs and selected REMP TLDs near the ISFSI Foundation

+ ISFSI TLD REMP TLD s

00 0 00 Figure 10 - SONGS ISFSI and Selected REMP TLD Locations Page j 59

APPENDIX I 2020 AREOR APPENDIX I. OFFSITE GROUND WATER SAMPLING Offsite Drinking Water All investigations have shown that there are no drinking water pathways at SONGS.

Figure 11 below illustrates groundwater well locations along with the flow of the groundwater. SONGS had no impact on drinking water wells in the vicinity of SONGS.

Figure 11 - Closest Drinking Water Wells Page I 60

Glossary 2020 AREOR Glossary a posteriori After the fact a priori Before the fact ALARA As Low As is Reasonably Achievable means making every reasonable effort to maintain exposures to radiation as far below the dose limits in this part as is practical consistent with the purpose for which the licensed activity is undertaken , taking into account the state of technology , the economics of improvements in relation to state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest.

Cosmogenic Radionuclides (or isotopes) created when a high-energy cosmic ray nuclides interacts with the nucleus of an atom . These isotopes are produced within Earth materials such as rocks or soil , in Earth's atmosphere, and in extraterrestrial items such as meteorites. Radioactive isotopes beryllium-? and beryllium-1 O fall into this series of three light elements (lithium , beryllium , boron) formed mostly by cosmic ray spallation nucleosynthesis, both of these nuclides have half-lives too short for them to have been formed before the formation of the Solar System ,

and thus they cannot be primordial nuclides. Since the cosmic ray spallation route is the only possible source of beryllium-? and beryllium-10 occurrence naturally in the environment, they are therefore cosmogenic.

Below is a list of radioisotopes formed by the action of cosmic rays in the atmosphere; the list also contains the production mode of the isotope.

Isotope Mode of formation Isotope Mode of formation 3H 32p 14N (n , 12c)3H Spallation (Ar)

(tritium) 7Be Spallation (N and 0) 34mcI Spallation (Ar) 10 Be Spallation (N and 0) 3ss Spallation (Ar) 11 c Spallation (N and 0) 3scI 3scI (n , y) 3scI 14c 14N (n, p) 14c 37Ar 37 CI (p , n) 37 Ar 1sF 18 0 (p, n) 18F and 3scI Spallation (Ar)

Spallation (Ar) 22Na Spallation (Ar) 39Ar 3sAr (n , y) 39Ar 40Ar (n , np) 39 CI &

24Na Spallation (Ar) 39CI spallation (Ar) 2sMg Spallation (Ar) 41 Ar 40Ar (n , y)41 Ar 31 Si Spallation (Ar) s1 Kr 8°Kr (n , y) 81 Kr 32Si Spallation (Ar)

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Glossary 2020 AREOR Decay Series There are three naturally occurring decay series of heavy elements that transform into a series of various radioactive elements by releasing energy in the form of particles, (such as alpha or beta) , and/or gamma rays to end in a stable form of non-radioactive Lead . All three decay series start with extremely long lived radioactive, heavy elements that can be measured in geologic time units. They are Uranium-238 with an approximate half-life of 4.5 billion years, Uranium -235 with a half-life of about 700 million years, and Thorium- 232 with a half-life of 14 billion years. All three series contain some more well-known radioactive species , Radium and Radon .

Distinguishable Detectable concentration of a radionuclide that is statistically different from from the background concentration of that radionuclide at that location.

background Dose The amount of radiation that is absorbed by a person's body. In the radiation field the term dose is sometimes used interchangeably with dose equivalent.

Exclusion Area The boundary used for routine effluent calculations required by 10 CFR Boundary (EAB) 20 at San Onofre Units 2 and 3; formed by two semi-circles with rad ii of 1967.5 ft. from the containment centers with a tangent connecting the landward and the seaward arcs.

Half-life A measure of how fast half the mass of a radioactive element will transform itself into another element. Each radioactive element has its own unique rate of transformation. Consequently , if a radioactive element, such as lodine-131 has a half-life of 8 days, then in 8 days half of the original amount of lodine-131 will be gone; in another 8 days half of that half will be left and so on.

Gamma A scientific method used to analyze gamma rays emanating from Spectroscopy radioactive elements. The analytical system determines the gamma ray energy which acts as a "fingerprint" for specific radioactive materials.

For example , Potassium-40 (K-40) has a very, distinctive gamma energy at 1460 keV. This uniqueness allows the instrument to positively identify the K-40 1460 energy as its own unique fingerprint. A keV is an abbreviation for kilo electron volt, which is a measure of energy at the atomic level. A kilo is a scientific prefix for the multiplier 1,000.

Gross Beta A screening technique employed to measure the total number of beta particles emanating from a radioactive sample, without isotopic identification. At SONGS samples with an elevated gross beta are analyzed by gamma spectroscopy to identify the specific radionuclides causing the elevated gross beta signal. A beta particle is a negatively charged particle a mass equal to that of an orbiting electron.

Liquid The analytical technique by which tritium activity is measured in water.

Scintillation A sample is placed in a glass vial containing scintillation cocktail. The mixture is sealed and homogenized. When the tritium decays it emits a very low energy beta particle. The beta interacts with the scintillating medium and produces a light pulse that is counted by the instrument.

Millirem (mrem) One thousandth (1/1000) of a rem .

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Glossary 2020 AREOR milliRoentgen One thousandth (1/1000) of a Roentgen (mR) pCi/kg An acronym for a pico-curie per kilogram , which is a concentration unit that defines how much radioactivity is present in a unit mass, such as a kilogram . A "pico" is a scientific prefix for an exponential term that is equivalent to one trillionth (1/1 ,000,000,000 ,000) .

pCi/1 An acronym for a pico-curie per liter, which is a concentration unit that defines how much radioactivity is present in a unit volume, such as a liter.

Rem An acronym for roentgen equivalent man. It is a conventional unit of dose equivalent that is based on how much of the radiation energy is absorbed by the body multiplied by a quality factor, which is a measure of the relative hazard of energy transfer by different particles, (alpha, beta , neutrons, protons, etc.), gamma rays or x-rays. In comparison the average natural background radiation dose equivalent to the United States population is estimated to be 292 millirems per year, or 0.8 millirem per day, with 68 % of that dose coming from radon. A millirem is one thousandth , (1/1000) , of a rem.

Roentgen A special unit of exposure named after the discoverer of X-Rays, Wilhelm Roentgen. It is a measure of how much ionization is produced in the air when it is bombarded with X-Rays or Gamma Rays. Ionization is described as the removal of an orbital electron from an atom.

Skyshine Radiation from a radioactive source that bounces off air molecules in the sky, much like a cue ball does off the banking of a billiard table, and is scattered/redirected back down to the earth.

Thermolum ines Very small plastic-like phosphors or crystals that are placed in a small cent Dosimeters plastic cage and mounted on trees, posts, etc. to absorb any radiation (TLD) that impinges on the material. Special readers are then used to heat the plastic to release the energy that was stored when the radiation was absorbed by the plastic. The energy released is in the form of light and that light is counted by the TLD reader. The intensity of the light emitted from the crystals is directly proportional to the amount of radiation that the TLD phosphor was exposed to.

Tritium H-3 is the naturally occurring radioactive form of Hydrogen. All (Hydrogen-3 or radioactive elements are represented as a combination of their chemical H-3) symbol and their mass number. Therefore, Tritium , which is a heavy form of the Hydrogen molecule with one proton and two neutrons in the nucleus of its atom , is abbreviated and represented by its chemical symbol , H-3, for Hydrogen and 3 for the number of particles in its nucleus, or mass number. Similarly, other radioactive elements, such as Potassium-40, can be represented and abbreviated as K-40, and so on.

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