NOC-AE-21003802, 2020 South Texas Project Electric Generating Station Annual Environmental Operating Report

2020 South Texas Project Electric Generating Station Annual Environmental Operating Report

ML21116A414
Person / Time
Site:	South Texas
Issue date:	04/26/2021
From:	Stone C South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-21003802, STI: 35157452
Download: ML21116A414 (76)

Text

Nuclear Operating Company South Texas Pro/ect Electric Generating Station P.O. Box 289 Wadnmrth, Texas 77483 April 26, 2021 NOC-AE-21003802 10CFR50.36b STI: 35157452 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket Nos. 50-498; 50-499 2020 South Texas Project Electric Generating Station Annual Environmental Operating Report Pursuant to the South Texas Project Unit 1 Renewed Operating License NPF-76 and Unit 2 Renewed Operating License NPF-80 Appendix B, Environmental Protection Plan (Non-radiological), and Technical Specification 6.9.1,3, the STP Nuclear Operating Company provides the attached South Texas Project Electric Generating Station 2020 Annual Environmental Operating Report.

There are no commitments in this letter.

If there are any questions about this report, please contact me at 361-972-8168, or Zachary Dibbern at 361-972-4336.

Clayton B. Stone Manager, Health Physics ZD

Attachment:

2020 Annual Environmental Operating Report

NOC-AE-21003802 Page 2 of 2 ec:

Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 1600 E. Lamar Boulevard Arlington, TX 76011-4511 Matagorda County Judge Nate McDonald 1700 7th Street Room 301 Bay City, TX 77414-5094 Commissioner PCT. 1 Edward Cook 2604 Nichols Road Bay City, TX 77414 Commissioner PCT. 2 Kent Pollard P.O. Box 571 Matagorda, TX 77457 Commissioner PCT. 3 Troy Shimek 25000 Hwy 35 South Palacios,TX 77465 Commissioner PCT. 4 Charles Frick P.O. Box 99 El Maton, TX 77440 Texas Dept. of State Health Services Robert Free PO Box 149347 Austin, TX 78714-9347

S OUTH TEXAS PROJECT ELECTRIC GENERATION STATION 2020 ANNUAL ENVIRONMENTAL OPERATING REPORT

The 2020 Annual Environmental Operating Report for the South Texas Project Electric Generating Station combines in one report the requirements for the Annual Environmental Operating Report (Non-radiological) found in Appendix B to the renewed Facility Operating License Nos. NPF-76 and NPF-80 and the requirements for the Annual Radiological Environmental Operating Report found in Part A of the stations Offsite Dose Calculation Manual.

Completed in accordance with Technical Specifications for United States Nuclear Regulatory Commission Renewed License Nos.NPF-76 and NPF-80 April 2021 Authored by: _______________________

Laura Stoicescu, CHP Consulting Health Physicist Health Physics Division and _______________________

Kenneth M. Cunningham Environmental Supervisor Regulatory Affairs Technical Review: _______________________

Edmond Hardcastle Jr.

Staff Environmental Radiological Services Specialist Health Physics Division Approved by: _______________________

Clayton B. Stone Manager Health Physics Division 2020 Annual Environmental Operating Report Maps provided by Janice Hopes Photos courtesy of:

Cheryl Bentley, Aubrey Passafuma, Christie Dement, Greg McMullin, Joe King, Kimberly Smith, Roger Dement, Ronnie Ormand, Rudy Perez and Susan Branson Graphics by Diane Davis Design STP ANNUAL ENVI RONM E N TAL OP E RAT I N G RE P ORT

TA B L E O F C O N T E N T S CHAPTERS CHAPTER ONE: EXECUTIVE

SUMMARY

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 CHAPTER TWO: SITE AND AREA DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 CHAPTER THREE: NON-RADIOLOGICAL ENVIRONMENTAL INTRODUCTION AND

SUMMARY

. . . . 3-1 CHAPTER FOUR: NON-RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT . . . . . . . . . . . . . . 4-1 Environmental Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Aquatic and Ecological Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Water Quality Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Air Quality Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Non-radioactive Waste Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Chemical Control and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9 Environmental Protection Plan Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 CHAPTER FIVE: RADIOLOGICAL ENVIRONMENTAL INTRODUCTION AND

SUMMARY

. . . . . . . . . . 5-1 CHAPTER SIX: RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT. . . . . . . . . . . . . . . . . . . . . 6-1 Program Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 Airborne Pathway. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6 Direct Exposure Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 Sediment Samples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 Waterborne Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9 NEI Groundwater Protection Initiative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13 Land Use Census. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 Quality Assurance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18 Program Deviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18 Radiological Environmental Monitoring Program Analysis Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28 LIST OF FIGURES Figure 2-1: Plant Water Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 Figure 4-1: 2020 Nonradioactive Waste Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8 Figure 4-2: 2020 Nonradioactive Waste Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9 Figure 4-3: Hazardous Waste Shipped Historical Comparison. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9 Figure 6-1: Radiological Environmental Monitoring Program Designated Sample Location Map. . . . . . . . . . . . . . . . . . 6-3 Figure 6-2: Radiological Environmental Monitoring Program Onsite Sample Location Map . . . . . . . . . . . . . . . . . . . . . 6-4 Figure 6-3: Radiological Environmental Monitoring Program Zone Location Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 Figure 6-4: Historical Comparison of Average Quarterly Beta Activity from Indicator and Control Air Samples . . . . . . . 6-6 Figure 6-5: Environmental Dosimeter Comparisons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 Figure 6-6: Historical Comparison of Cobalt-60 in Main Cooling Reservoir Sediment. . . . . . . . . . . . . . . . . . . . . . . . . . 6-8 Figure 6-7: Calculated Cumulative Curies of Cobalt-60 in the Main Cooling Reservoir. . . . . . . . . . . . . . . . . . . . . . . . . 6-8 Figure 6-8: Historical Comparison of Tritium Added to and Remaining in the Main Cooling Reservoir. . . . . . . . . . . . . . 6-10 Figure 6-9: Historical Comparison of Tritium Activity in Reservoir Relief Wells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10 Figure 6-10: Historical Comparison of Tritium Activity in Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11 Figure 6-11: Historical Comparison of Tritium Activity in Shallow Aquifer Ground Water. . . . . . . . . . . . . . . . . . . . . . . . 6-12 Figure 6-12: Tritium Activity in Shallow Ground Water West of the Main Cooling Reservoir. . . . . . . . . . . . . . . . . . . . . . 6-13 Figure 6-13: STP Protected Area Ground Water Monitoring Wells Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14 Figure 6-14: STP Protected Area Ground Water Monitoring Wells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14 Figure 6-15: 2020 Radiological Laboratory Quality Assurance Program Performance . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 Figure 6-16: Duplicate & Split Agreement of Environmental Samples in 2020 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 L I S T O F TA B L E S Table 1: Radiological Environmental Monitoring Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-19 to 6-21 Table 2: Sample Media and Location Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23 to 6-27 Table 3: 2020 Radiological Environmental Monitoring Program Analysis Summary. . . . . . . . . . . . . . . . . . . . . . 6-29 to 6-45

STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT MESSAGE FROM THE PRESIDENT AND CEO For over thirty years, STP has produced safe, carbon-free, clean-air energy at our site in beautiful Matagorda County with great respect and admiration for the land, water and air we all share.

Matagorda County prides itself on the beauty and variety of the ecosystems and wildlife that thrive here.

It harbors a unique convergence of those ecosystems, including secluded, extensive forests, waterways, riparian wetlands, an expansive prairie and 40 miles of beautiful, wild coastline. Its uniqueness as prime habitat for wildlife is evidenced by it being consistently named as the county with the greatest variety of migratory birds than in any other county in the United States. STP is committed to caring for the natural resources with which we have been entrusted. We want Matagorda County residents to know that STPs dedication to protecting the environment will not diminish, and it is our great privilege to operate on this land that we all call home. Transparency in our environmental operations is a key element to maintaining our trust and good relationship with our community. This report exemplifies our dedication to maintaining this open communication.

Thank you for allowing us to continue to be your trusted neighbor. We look forward to serving this community and being a steward of our environment for many years to come.

Tim Powell President and CEO STP Nuclear Operating Company Photo courtesy of Greg McMullin M E S SAG E F R O M T H E P R E SID ENT AND C EO

EXECUTIVE

SUMMARY

1-1 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

CHAPTER: ONE The South Texas Project Electric Generating Station Non-radiological environmental monitoring is performed each (South Texas Project) continues to operate with no year as part of the stations overall Environmental Protection adverse effect on the population or the environment. The Plan which is intended to provide for protection of non-dose equivalent for people living in the area remains at radiological environmental parameters during station operations.

less than one millirem per year. Environmental programs Non-radiological monitoring encompasses, as a minimum, at the site monitor known and predictable relationships water quality, air quality, waste generation and minimization, between the operation of the South Texas Project and and local aquatic and terrestrial ecological conditions. In the surrounding area. These monitoring programs 2020, non-radiological monitoring by the station confirmed verify that the operation of the South Texas Project has that the South Texas Projects efforts to respect and protect no impact offsite and is well below state and federal local environmental conditions were successful. The operation regulations and guidelines. These programs are verified of South Texas Project continued to provide high-quality by the State of Texas through collection and analysis habitat areas for a variety of flora and fauna and continued to of samples and placement of the States monitoring have no indications of negative non-radiological impacts to dosimeters and other onsite and offsite inspections.

local environmental conditions.

This report describes the environmental monitoring programs, The environment within a 15-mile radius of the South Texas non-radiological and radiological, conducted at the South Project is routinely monitored for radiation and radioactivity.

Texas Project during 2020. Included in this report are the Sampling locations are selected using weather, land use, Environmental Protection Plan Status, the results of the and water use information. Two types of sampling locations Radiological Environmental Monitoring Program, and the are used. The first type, control stations, are located in areas Land Use Census.

Photo courtesy of Rudy Perez Photo courtesy of Aubrey Passafuma CH A PT E R 0 N E l E X E CU T I V E

SUMMARY

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of state-of-the-art scientific instruments. Samples with radiation levels that cannot be detected are below the Lower Limits of Detection. The United States Nuclear Regulatory Commission requires that equipment used for radiological monitoring must be able to detect specified minimum limits for certain types of samples. This ensures that radiation measurements are sufficiently sensitive to detect small changes in the environment. The United States Nuclear Regulatory Commission also has a required reporting level.

Licensed nuclear facilities must prepare a special report and increase their sampling if any measured radiation level is equal to or greater than this reporting level. No sample from Photo courtesy of Aubrey Passafuma the South Texas Project has ever reached or exceeded this reporting level. Measurements performed are divided into four categories, or pathways, based upon how the results may affect the public. Airborne, waterborne, ingestion, and direct radiation are the four pathways that are sampled. Each pathway is described on page 1-4.

The South Texas Project continues to operate with no adverse effect on the population or the environment. The Photo courtesy of Kimberly Smith dose equivalent for people living in the area is maintained at that are beyond the measurable influence of the South Texas less than one millirem per year. Environmental programs at Project or any other nuclear facility. The sample results from the site monitor known and predictable relationships between these stations are used to explain radiation from sources the operation of the South Texas Project and the surrounding other than the South Texas Project. Indicator stations are area. These monitoring programs verify that the operation the second type of station. The samples from these stations of the South Texas Project has no impact offsite and is well measure any radiation contributed to the environment that within state and federal regulations and guidelines. These could be caused by the South Texas Project. Indicator programs are verified by United States Nuclear Regulatory stations are located in areas close to the South Texas Project Commission inspections and the State of Texas through where any plant releases would be detected. collection and analysis of samples and state radiation monitoring dosimeters.

Prior to initial operation of the South Texas Project, samples were collected and analyzed to determine the amount of radioactivity present in the area. These results are used as a pre-operational baseline. Results from the indicator stations are compared to both current control sample results and the pre-operational baseline values to determine if changes in radioactivity levels are attributable to station operations or other causes such as previous nuclear weapons testing programs and natural variations.

Photo courtesy of Rudy Perez Radioactivity levels in the South Texas Projects environment frequently fall below the minimum detection capabilities 1-3 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Greg McMullin EACH OF THE FOUR PATHWAYS

• T  he airborne pathway is sampled in areas around the South Previously detected plant-related nuclides, such as cobalt-60 Texas Project by measuring the levels of radioactive iodine and cesium-137, were detected in the reservoir sediment at and particulate radioactivity on air filters. The 2020 airborne designated sample locations at very low concentrations.

results were similar to pre-operational levels detecting only Additional samples had detectable cesium-137 which is naturally occurring radioactive material unrelated to the normally present in the environment and is consistent with operation of the South Texas Project. pre-operational concentrations. Onsite sediment samples continue to occasionally indicate traces of plant-related

• The waterborne pathway includes samples taken from nuclides such as cobalt-60. Offsite sediment samples surface water, groundwater, and drinking water. Also continue to show no radioactivity from the South Texas included in this pathway are sediment samples taken from Project. In summary, the station produced no detectable the Main Cooling Reservoir and the Colorado River. Tritium waterborne effects offsite.

was the only man-made nuclide consistently detected in water samples and was measured in the shallow aquifer, the * The ingestion pathway includes broadleaf vegetation, Main Cooling Reservoir, ditches, and sloughs consistent with agricultural products, and food products. Naturally occurring the South Texas Project Main Cooling Reservoir operating nuclides were detected at average environmental levels in design. The levels of tritium found were near or lower than the samples. The data indicated there were no man-made the concentration of tritium in the Main Cooling Reservoir. nuclides detected in these types of samples.

Additional onsite wells have been sampled to map tritium

• The direct exposure pathway measures environmental migration. The average tritium level in the Main Cooling radiation doses using thermoluminescent dosimeters. These Reservoir remained stable throughout 2020. Tritium results are consistent with the readings from previous years levels remain well below United States Nuclear Regulatory and pre-operational measurements indicating no effect from Commission reporting limits and within United States South Texas Project operations.

Environmental Protection Agency drinking water standards.

CH A PT E R 0 N E l E X E CU T I V E

SUMMARY

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SITE AND AREA DESCRIPTION 2-1 ST P ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

CHAPTER: TWO The South Texas Project is located on 12,220 acres in Matagorda County, Texas, approximately 15 miles southwest of Bay City along the west bank of the Colorado River. The South Texas Project is owned by NRG South Texas LP, City of Austin, and City Public Service Board of San Antonio as tenants in common.

Houston Lighting & Power Company was the original project manager of the South Texas Project and was responsible for the engineering, design, licensing, construction, startup, and initial commercial operation of Photo courtesy of Greg McMullin the two-unit facility. In 1997, the STP Nuclear Operating Company assumed operational control of the South Texas Project and responsibility for implementation of associated environmental programs.

The South Texas Project has two Westinghouse pressurized water reactors. The rated core thermal power of each unit is 3,853 megawatts-thermal (MWt). Each unit was Photo courtesy of Kimberly Smith originally designed for a net electrical power output of The combined units currently produce enough electricity 1,250 megawatts-electric (MWe). Unit 1 received a low- to serve more than two million homes and businesses power testing license on August 21, 1987, achieved initial throughout Texas. With approximately 1,100 baseline criticality on March 8, 1988, and was declared commercially employees, the STP Nuclear Operating Company is the operational on August 25, 1988. Unit 2 received a low- largest employer and source of revenue for Matagorda power testing license on December 16, 1988, achieved initial County. Nuclear energy continues to provide long-term cost criticality on March 12, 1989, and was declared commercially stability and promote energy independence. It is our nations operational on June 19, 1989. On September 28, 2017, the largest source of carbon- free energy. As we work collectively United States Nuclear Regulatory Commission approved to secure our states long-term energy future, nuclear energy the South Texas Projects request to extend the operating will continue to play an important role as a safe and reliable licenses an additional twenty years through 2047 and 2048. supply of clean baseload electricity.

HOW THE SOUTH TEXAS PROJECT WORKS Fossil-fueled and nuclear-powered steam generating plants a boiler to produce the heat. In a nuclear plant, the reactor operate on the same principle. Fuel is used to produce heat replaces the boiler and the fissioning or splitting of uranium to convert atoms inside the reactor produces the heat.

water into high-The fuel for a nuclear reactor is uranium. It is formed into pressure steam.

cylindrical ceramic pellets, each about the size of the end of The steam is Photo courtesy of Greg McMullin your little finger. One pellet has the energy potential of about directed through a ton of coal. Millions of these pellets are stacked in fuel rods a turbine to turn that are arranged into assemblies that make up the core of a generator. In a the reactor. The use of uranium allows us to conserve natural fossil fuel plant, gas, oil and coal and to avoid the associated production of either coal, lignite, greenhouse gases. The fission process and generation of oil or natural usable heat begins in a nuclear reactor when control rods gas is burned in Photo courtesy of Greg McMullin CH A PT E R T WO l S I T E A N D A R E A D E S C R IPT ION 2-2

PLANT WATER SYSTEMS Figure. 2-1 in the core are withdrawn. In pressurized water reactors, built-in physical barriers designed to prevent the release of like those at the South Texas Project, the fuel rods heat radioactive materials in the unlikely event of an accident. The water circulating in sealed, stainless steel piping that passes most visible ones are the 200-foot-tall, domed containment through large heat exchangers called steam generators. The buildings with steel reinforced concrete walls four feet thick.

water in the reactor is under pressure to prevent boiling. This Inside each of these massive structures, two more concrete is why the South Texas Projects Units 1 and 2 reactors are walls provide another 11 feet of radiation shielding. The called pressurized water reactors. reactor vessel itself has steel walls six inches thick, and the fuel pellets inside it are sheathed in hardened metal tubes.

This hot, pressurized water heats a separate supply of water in the steam generators to produce steam that is directed Nuclear energy has one of the lowest impacts on the through the blades of a turbine generator to produce environment. It is the most eco-efficient energy source electricity. The steam is because it produces the most electricity in relation to its then fed to a condenser minimal environmental impact. In 2018, the most recent year where a separate for which data is available, nuclear generation in the United supply of cooling water States prevented 528 million metric tons of carbon dioxide, from the Main Cooling 0.35 million short tons of sulfur dioxide, and 0.29 million short Reservoir condenses it tons of nitrogen oxide from entering the Earths atmosphere.1 back into water that is Nuclear power plants also generated approximately 55 then pumped back to percent of the emission-free electricity generation in the United Photo courtesy of Greg McMullin the steam generator for States in 2018.1 Additional information on nuclear energy and reuse. A diagram of the the environment can be found on the website maintained by plant water systems is the Nuclear Energy Institute at www.nei.org.

shown in Figure 2-1.

Nuclear Energy Institute. Nuclear by the Numbers; August 2020.

1

In addition to its safety As viewed at www.nei.org/CorporateSite/media/filefolder/resources/

systems, the South fact-sheets/nei-nuclear-by-the-numbers-092520-final.pdf.

Photo courtesy of Greg McMullin Texas Project has many 2-3 ST P ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

THE PLANT SITE Sixty-five of the total 12,220 acres at the South Texas Project are occupied by the two current power plants. Plant facilities include a 7,000-acre main cooling reservoir and a 47-acre essential cooling pond. Many smaller bodies of water onsite include wetlands, Kelly Lake, drainage ditches, sloughs, and depressions. Much of the land east of the cooling reservoir is leased for cattle grazing. Approximately 1,700 acres remain in a more natural state as a lowland habitat. A 110-acre wetland habitat area was established in 1996 on previously unused land located northeast of the power plants. The area surrounding the South Texas Project is characterized by coastal plain with farmland and pasture predominating. Local Photo courtesy of Greg McMullin relief of the area is characterized by flat land, approximately 23 feet above sea level.

THE AREA Matagorda Countys economy is based primarily on ranching, The South Texas Project is home to many species of animals.

farming, oil and natural gas production and refinement, Inhabitants include American alligators, a variety of birds, petrochemical production, electricity generation, and and several hundred deer. In winter, literally hundreds of commercial fishing and fisheries. The area within 10 miles thousands of waterfowl, principally migratory geese as well as of the site is generally rural and characterized as farmland, white pelicans, have found that the plants 7,000-acre cooling which is primarily pastureland used for livestock ranching. reservoir provides a good resting place during their migrations.

Although the surrounding area is heavily cultivated, significant The climate of the region is subtropical maritime, with amounts of woodlands, thicket, brush, fields, marsh, and continental influence. It is characterized by short, mild winters open water exist to support wildlife. The area lies in the and long, hot and humid summers. Rainfall normally ranges southern region of the central flyway and is host to an from about two inches per month in February peaking to abundance of migratory birds. The local estuary environments about four to five inches per month in May, June, September provide the necessary habitat for a variety of fish types to and October. The prevailing wind direction is from the south-complete their life cycles. The area also affords opportunity southeast, shifting to north-northeast for short intervals during for recreational hunting and fishing.

the winter months.

Photo courtesy of Aubrey Passafuma CH A PT E R T WO l S I T E A N D A R E A D E S C R IPT ION 2-4

NON-RADIOLOGICAL ENVIRONMENTAL INTRODUCTION AND

SUMMARY

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CHAPTER: THREE Nonradiological environmental conditions and commitment to sound environmental management in performance at the South Texas Project during 2020 2020 is illustrated below.

remained satisfactory and demonstrated that the South Everyone at the South Texas Project has a responsibility to Texas Project continued to operate in an environmentally protect the environment. Commitment to environmental safety responsible manner during the year. The South Texas is an integral component of the South Texas Project operating Project achieved and maintained high standards of policy and core values. This responsibility reaches further than environmental performance and compliance mere compliance with laws and regulations to encompass throughout 2020.

the integration of sound environmental practices into our daily The South Texas Project is committed to the production operational and business decisions. The people at the South of electricity in a safe, reliable, and economical manner Texas Project understand the need to balance economic, using nuclear energy. The stations programs, policies, and operational and environmental issues for the benefit of the business plan objectives also incorporate a commitment to station and the public. We recognize our responsibility to hold environmental protection and management. The stations ourselves to the highest principles of environmental stewardship.

THE STATIONS COMMITMENT TO S OUND ENVIRONMENTAL MANAGEMENT IN 2020

• Satisfactory performance * Maintained safe, reliable and * Completion of a wastewater classification2 by the Texas environmentally compliant inspection by the Texas Commission on Environmental operations throughout the Commission on Environmental Quality based on the stations Covid-19 pandemic. Quality with no violations or environmental compliance record findings identified.

in all areas considered, including water quality, waste management, and air quality compliance.

2

 er Compliance History Report for CN601658669, RN102395654, Rating Year 2020; as prepared by the Texas Commission on P

Environmental Quality.

Photo courtesy of Christie Dement Photo courtesy of Greg McMullin C H APT E R T H RE E l N O N - R A D I O LO G I CA L E N V I R O N M E N TA L I N T R O D U CT I O N A N D

SUMMARY

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NON-RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT 4-1 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

CHAPTER: FOUR E N V I R O N M E N TA L C O N D I T I O N S This section of the report describes the South Texas Projects nonradiological environmental program performance and environmental conditions for 2020.

The STP Nuclear Operating Company employees closely monitor environmental conditions at the South Texas Project. NRG Energy, Inc. provides support and technical assistance to the South Texas Project.

The Texas Commission on Environmental Quality rated the South Texas Project as a satisfactory performer in 2020 based on the stations environmental compliance record.

Facilities, such as the South Texas Project, can be classified by the state as a high performer, satisfactory performer, or unsatisfactory performer based on that facilitys compliance Photo courtesy of Greg McMullin history. The states classification of the South Texas Project be divided into two broad ecological areas bottomland and as a satisfactory performer was based on the stations upland areas - based on topography, soils, and vegetation.

environmental performance over the last five-year period.

The bottomland lowland habitat is a swampy, marshy area During the period of this report, the station continued to that provides an important habitat for birds and other wildlife promote green initiatives including the recycling of paper, and occupies approximately 1,700 acres of the site near the plastics and aluminum by site employees. The station also Colorado River. An upland spoil containment area, originally continued to support various bird counts and surveys in constructed in 1972 by the United States Army Corps of 2020 sponsored by federal and state agencies and volunteer Engineers, is included in this area. In addition, a 110-acre organizations such as the annual National Audubon Society wetland habitat area that attracts a variety of bird groups and Christmas Bird Count and the United States Fish and Wildlife other wildlife was established in 1996 on previously unused Services Colonial Waterbird Survey. land located northeast of the power plants. The remaining area of the site offers diverse habitats for mammals and AQUATIC AND ECOLOGICAL MONITORING several types of birds. The South Texas Project regularly The location of the South Texas Project falls within the Texas monitors the sites environs for changing conditions.

Land Resource Area designation as coastal prairie and can Ecological conditions onsite in 2020 remained generally unchanged and stable.

The South Texas Project is located on the state-sponsored Great Texas Coastal Birding Trail that spans the entire Texas Gulf Coast from Brownsville to the Louisiana border.

Matagorda County, in which the South Texas Project is Photo courtesy of Aubrey Passafuma located, consistently ranks at or near the top of the National Audubon Societys annual Christmas Bird Count for the number of species identified. Many bird species have been observed visiting the wetland habitat and elsewhere onsite.

These include the bald eagle, white-faced ibis, and brown pelican. Additional migratory and resident bird species such as a variety of ducks, geese, turkey and pelicans (both brown Photo courtesy of Kimberly Smith and white) have been observed during informal surveys of the C H A PT E R FO U R l N O N - R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 4-2

sites diverse natural and man-made habitats. Intensive bird virtually every aspect of business operations at the South nesting continues throughout the lowland habitat, particularly Texas Project. Water usage, wastewater treatment onsite in a heron rookery around the perimeter of Kelly Lake and and certain maintenance and repair activities are regulated on the internal dikes of the Main Cooling Reservoir at the under the Safe Drinking Water Act, the Federal Clean Water South Texas Project. The South Texas Project continues to Act, and the Texas Water Quality Act. Collectively, these acts provide vital habitat for more than an estimated 125 species of wintering and resident birds.

The South Texas Project continues to monitor important wildlife species to detect population changes. Informal observations continue to indicate that the site provides high-quality habitat in which a wide range of animals thrive. The site continues to attract extensive wildlife populations, offering a Photo courtesy of Greg McMullin refuge for resident species as well as seasonal migrants. The lowland habitat located between the Colorado River and the east bank of the Main Cooling Reservoir offers a significant source of water year-round. These natural resource areas, in concert with numerous additional wetland and grassland Photo courtesy of Greg McMullin areas, offer the key ingredients necessary to sustain the provide for the safeguarding of public drinking water supplies extensive wildlife population at the South Texas Project.

and maintaining the integrity of state and federal waters.

WATER QUALITY MANAGEMENT Regulating agencies that administer these requirements Water is an essential component in electricity production, include the United States Army Corps of Engineers, the and electric utilities must comply with extensive federal, United States Environmental Protection Agency, the Texas state and local water regulations. These regulations govern Commission on Environmental Quality, the Texas General Photo courtesy of Greg McMullin 4-3 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Land Office the Lower Colorado River Authority and the Coastal Plains Groundwater Conservation District.

The South Texas Project uses both surface water and groundwater for station purposes. Consistent with the stations environmental principles encouraging efficient water usage and conservation, surface and groundwater usage are carefully managed to conserve this important resource.

Groundwater is pumped from deep aquifer wells to provide onsite drinking water for station personnel, to replenish the Essential Cooling Pond, and for other industrial purposes onsite. Water from the Main Cooling Reservoir and the Essential Cooling Pond is used as cooling water for plant operations. Water from the Colorado River replenishes the Main Cooling Reservoir via intermittent diversion periods.

Surface water diverted to the Main Cooling Reservoir from the Colorado River accounted for approximately 90 percent of the water used at the South Texas Project in 2020.

Information regarding water use in Texas can be found on the website maintained by the Texas Water Development Board at www.twdb.texas.gov.

Most of the water used by the South Texas Project is needed to condense steam and provide cooling for plant generating Photo courtesy of Joe King systems. The majority of this water is drawn from and was withdrawn from onsite groundwater sources in 2020.

returned to the stations Main Cooling Reservoir. The Main Cooling Reservoir is a 7,000-acre, above grade, off-channel Existing federal and state water quality standards are reservoir capable of impounding 202,600 acre- feet of water implemented and enforced through the Texas Pollutant at its maximum level. Water is diverted intermittently from Discharge Elimination System (TPDES) permit program to the adjacent Colorado River to replenish the Main Cooling restore and maintain the states waters. Under this permit Reservoir. In addition, the Essential Cooling Pond, a 47-acre, program, the South Texas Project monitors, records, and below grade, off-channel reservoir that supplies water to cool reports the types and quantities of pollutants from wastewater crucial plant components, is capable of impounding 388 discharges to ensure that the South Texas Project meets acre-feet of water. Various water rights permits, contractual the stringent levels set in the permit. The TPDES permit was agreements, and compliance documents authorize the South renewed in 2020. A monthly monitoring report is submitted Texas Project to maintain these reservoirs, impound water to the Texas Commission on Environmental Quality for diverted from the Colorado River, and to circulate, divert, wastewater discharges. In 2020, the Texas Commission and use water from the reservoirs for industrial purposes to on Environmental Quality conducted an extensive virtual operate the plant. These authorizations also limit the amount wastewater inspection and records review. No findings or and rate of diversion from the Colorado River to protect violations were identified during the inspection. Reports downstream environmental flow requirements for bays and identifying groundwater use, surface water use and water estuaries. The South Texas Project diverted 12,795 acre-feet conservation are submitted annually to the Texas Water in 2020 from the Colorado River for Main Cooling Reservoir Development Board. Reports of surface water diversion and fill operations while preserving adequate freshwater flow consumptive use are submitted to the Texas Commission conditions for downstream bay and estuarine ecosystems. on Environmental Quality and the Lower Colorado River Approximately 1,301 acre-feet of the water used by the station Authority. An annual groundwater use report is also submitted C H A PT E R FO U R l N O N - R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 4-4

to the Coastal Plains Groundwater Conservation District in drafted legislation known as Senate Bill 1 to address these accordance with groundwater district requirements. issues and to develop a comprehensive state water policy.

The legislation required the Texas Water Development Wastewater generated at the South Texas Project is Board to create a statewide water plan that emphasizes processed and discharged to the onsite Main Cooling regional planning. Sixteen planning regions were created, Reservoir to be re-used by the station as cooling water for each tasked to prepare a plan for the orderly development, plant systems. No water was discharged from the Main management, and conservation of water resources. The Cooling Reservoir in 2020 other than from the relief wells that South Texas Project was chosen to represent the interests are part of the reservoir embankment stabilization system.

of electric generating utilities for water-planning Region K, No aquatic monitoring was required to be conducted at the encompassing the lower Colorado River Basin. A state water site in 2020 by the United States Environmental Protection plan is prepared by the Texas Water Development Board Agency or the Texas Commission on Environmental Quality.

every five years based on the regional water plans. The fifth Wastewater discharges met state and federal water quality cycle of regional and state water planning concluded in 2020 standards during the year, while conserving and maximizing and the sixth planning cycle will commence in 2021. The efficient water usage at the South Texas Project. In addition to regional water plans are revised each planning cycle based the wastewater discharge permit program, the Federal Clean on updated population and water demand projections, water Water Act, as amended, requires permits for storm water supply analyses, and water management strategies for a discharges associated with industrial activity. The South Texas water planning horizon out to the year 2070. In November of 2020, the water plan adopted by the Region K water planning group was submitted to the Texas Water Development Board for approval. The South Texas Project continues to actively participate in the Lower Colorado Regional Water Planning Group to identify strategies to meet future water supply demand projections for the region and to update the existing plan accordingly. Additional information regarding regional water planning in Texas can be found on the website maintained by the Texas Water Development Board at www.

twdb.texas.gov.

Senate Bill 1 also required groundwater conservation districts to develop groundwater management plans with estimates Photo courtesy of Aubry Passafuma on the availability of groundwater in the district, details of how Projects Storm Water Pollution Prevention Plan ensures the district would manage groundwater, and management that potential pollution sources at the site are evaluated and goals for the district. The water planning and management that appropriate measures are selected and implemented to provisions were further clarified in 2001 with the enactment prevent or control the discharge of pollutants in storm water of Senate Bill 2. Accordingly, the Coastal Plains Groundwater runoff. This plan is a document that is revised whenever Conservation District, encompassing Matagorda County, was there is a change in design, construction, operation, or confirmed by local election in late 2001. The purpose of the maintenance that has a significant effect on the potential for District is to manage and protect the groundwater resources the discharge of pollutants from the station. The stations of the District. The South Texas Project groundwater wells are Multi-Sector General Permit for storm water discharges was registered with the Coastal Plains Groundwater Conservation last renewed in 2016. District. Operating permits for the groundwater wells were renewed in 2020, as required every three years. Station Following a severe drought in 1996, the Texas Legislature personnel continue to monitor onsite groundwater usage recognized the need to address a wide range of state water according to the requirements of District rules. Additional resource management issues. In 1997, the Texas Senate 4-5 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

the state, working with a science team, to develop a set of recommendations to the Texas Commission on Environmental Quality and to perform ongoing periodic reviews of the recommendations. The South Texas Project participated as a member of the stakeholder committee that included the Colorado River and Matagorda Bay. The environmental flow standards set flow levels at various points in rivers and streams to protect water in the rivers and estuaries along the coast. The existing South Texas Project right to divert surface water was not impacted by this legislation. Additional information regarding environmental flows can be found at www.tceq.texas.gov/permitting/water_rights/wr_technical-resources/eflows.

Photo courtesy of Greg McMullin information regarding the Coastal Plains Groundwater In February 2020, the Texas Commission on Environmental Conservation District can be found on its website at www. Quality approved a revised Lower Colorado River Authority coastalplainsgcd.com. In 2007, in further recognition of the Water Management Plan. The Lower Colorado River Authority importance of water conservation to meet future demands Water Management Plan determines how water is allocated in the state, Senate Bill 3, enacted by the Texas Legislature, from the Highland Lakes (specifically Lakes Travis and created a stakeholder-driven process for the development Buchanan) to meet the needs of water users, including the of environmental flows. Environmental flows are the amount South Texas Project, during water supply shortages. The of water necessary for a river, estuary, or other freshwater process started in 2019 when the Lower Colorado River system to maintain its health and productivity. The law Authority submitted an updated Water Management Plan to established a process to develop environmental flow regime the Texas Commission on Environmental Quality for approval.

recommendations for each major river basin in Texas. The The South Texas Project participated in the development of process tasked a team of stakeholders forom each area of the revision for presentation to and approval by the Texas Photo courtesy of Rudy Perez C H A PT E R FO U R l N O N - R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 4-6

Commission on Environmental Quality. Stakeholders included emission sources representatives from cities, industry, lake area businesses and at the South residents, environmental interests and agriculture. Additional Texas Project information on the Lower Colorado River Authority Water include fossil-Management Plan can be found at www.lcra.org. fueled emergency generators and fire In 1999, the South Texas Project implemented a station pumps, fire-fighting Water Conservation Plan in accordance with state water training, and other use regulations. The purpose of the Water Conservation minor maintenance Plan is to identify and establish principles, practices, and Photo courtesy of Greg McMullin equipment and standards to effectively conserve and efficiently use available activities. The station notified the Texas Commission on ground and surface water supplies and meet historical Environmental Quality of a change related to removal of one and projected average industrial water demand. Annual emergency diesel generator in 2020 and inapplicability of the implementation reports are submitted to the Texas Water Emissions Inventory program.

Development Board and the plan is updated every five years.

The station re-submitted a revised plan to the Texas Water The Federal Clean Air act mandates a permitting program to Development Board in 2019. Managers and staff at the South clearly define applicable air quality requirements for affected Texas Project understand the water resources of the state facilities such as the South Texas Project. This program is are a critical natural resource requiring careful management commonly known as the Title V Federal Operating Permit and conservation to preserve water quality and availability. Program and is administered by the state. In 2019, South Accordingly, the station continues to support efforts focusing Texas Project voided its Title V Federal Operating Permit in on the efficient use and conservation of water resources. lieu of certifying its emissions. The station is now registered under Permit By Rule Registration No. 154767. Certified AIR QUALITY MANAGEMENT emissions controls, like Title V, are federally enforceable Air emission sources at the South Texas Project fall under and must follow the guidelines of the Federal Clean Air act.

the scope of air pollution regulations promulgated under This Permit By Rule Registration grants authority to operate the Texas Clean Air Act and the Federal Clean Air Act and identified emission sources at the station in accordance with the numerous associated amendments. The purpose of applicable permit and regulatory requirements.

these regulations is to protect air resources from pollution by controlling or abating air pollution and harmful emissions. In 2020, South Texas Project had no reportable air emissions A report of air emissions is submitted annually to the Texas events and no violations.

Commission on Environmental Quality. Although nuclear Unlike conventional electrical generating stations, nuclear generation of electricity is a form of zero- emission clean power plants do not burn fossil fuel to produce electricity.

energy, the South Texas Project uses small amounts of Therefore, the South Texas Project produces virtually no fossil fuel for backup and emergency equipment. Regulated greenhouse gases or other air pollutants that are the typical Photo courtesy of Rudy Perez 4-7 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

by-products of industrial power production processes. and disposal activities are summarized and documented in The use of emissions-free nuclear power is a significant a waste summary report for the South Texas Project that is contributor to the preservation of our communitys clean submitted annually to the Texas Commission on Environmental air resources. Quality. The South Texas Porject five-year Source Reduction and Waste Minimization plan for hazardous waste was NONRADIOACTIVE WASTE MANAGEMENT last updated and the associated executive summary was Solid waste management procedures for hazardous and submitted to the non-hazardous wastes generated at the South Texas Project Texas Commission on ensure that wastes are properly dispositioned in accordance Environmental Quality with applicable federal, state, and local environmental and in 2019.

health regulations. By regulatory definition, solid waste includes solid, semi-solid, liquid, and gaseous waste material. Hazardous waste The Texas Commission on Environmental Quality, which accumulation at the administers the Texas Solid Waste Disposal Act and the South Texas Project federal Resource Conservation and Recovery Act program, in 2020 was limited to is the primary agency regulating non- radioactive wastes a maximum holding Photo courtesy of Greg McMullin generated at the South Texas Project. The Texas Commission period of 180 days.

on Environmental Quality regulates the collection, handling, The Resource Conservation and Recovery Act and Texas storage, and disposal of solid wastes, including hazardous Solid Waste Disposal Act also requires the use of proper wastes. The transportation of waste materials is regulated by storage and shipping containers, labels, manifests, reports, the United States Department of Transportation. personnel training, a spill control plan, and an accident contingency plan. South Texas Project personnel routinely The South Texas Project is classified as a small quantity inspect areas throughout the site to ensure wastes are not generator of industrial solid wastes. Texas Commission on stored or accumulated inappropriately.

Environmental Quality regulations require industrial solid wastes generated at the South Texas Project to be identified South Texas Project policies and regulations encourage the to the Commission. These are listed in the Texas Commission recycling, recovery, or reuse of waste when possible to reduce on Environmental Quality Notice of Registration for the South the amount of waste generated or disposed of in landfills.

Texas Project. The registration is revised whenever there is a Approximately 74 percent of the industrial nonradioactive change in waste management practices change at the site. waste generated in 2020 at the South Texas Project was Hazardous waste and Class I non- hazardous waste handling recycled or processed for reuse (Reference Figure 4-1). Used oil, diesel fuels, electro-hydraulic fluid, and used oil filters were sent to a recycling vendor for reprocessing. Empty polyethylene drums are returned, when possible, to the original manufacturer for reuse. In addition, the station supports recycling programs for cardboard, paper, aluminum, printer cartridges and plastic.

Approximately 49 tons of scrap metal were removed from the station for recycle in 2020.

The South Texas Project continues to explore new areas where recycling may be expanded or initiated.

Non-radioactive solid waste that cannot be Figure 4-1 shipped for recycling is shipped for disposal.

C H A PT E R FO U R l N O N - R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 4-8

Municipal type trash is transported to an offsite landfill. remain classified as a small-quantity waste generator since Hazardous waste accounts for only a small portion of the 2004. (Reference Figures 4-2 and 4-3).

waste generated at the South Texas Porject. Minimization CHEMICAL CONTROL AND MANAGEMENT and reduction of hazardous waste generation where feasible The stations Integrated Spill Contingency Plan for the remains an important goal.

South Texas Project, last updated and re-certified in 2019, Changes in the amount of consolidates multiple federal and state requirements into one hazardous waste shipped plan. The plan is implemented through standard site operating each year generally reflect procedures and guidelines. The South Texas Project uses differences in operation standard operating procedures, policies, and programs to and maintenance minimize the generation of waste materials, control chemical activities. Successful use, and prevent spills. The South Texas Project also waste minimization and evaluates chemicals and products prior to their approval source reduction efforts by for use at the station. Site procedures that implement the employees have allowed stations Integrated Spill Contingency Plan and the stations Photo courtesy of Greg McMullin the South Texas Project to Figure 4-2 Figure 4-3 4-9 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Chemical Control Program address the evaluation, storage, prevention and maintains readiness to respond should a spill use, labeling, spill control, and disposal requirements of occur. Spill response team members receive annual refresher chemicals. These guidelines also assist in reducing waste training in hazardous material incident response. The South generation, ensuring proper packaging for disposal and Texas Project did not have any reportable liquid spills in 2020.

mitigating the consequences of inadvertent spillage. The South Texas Project emphasizes awareness training for spill E N V I R O N M E N TA L P R OT E C T I O N P L A N S TAT U S The South Texas Projects Environmental Protection Plan at the time they are submitted to the cognizant agency.

was issued in March of 1989 to protect nonradiological If a nonroutine event occurs and a report is not required environmental monitoring parameters during operation of the by another agency, then a 30-day report to the United nuclear plants. This report reviews Environmental Protection States Nuclear Regulatory Commission is required by the Plan non-compliances, if any, identified in 2020 and the Environmental Protection Plan. No such 30-day or other non-associated corrective actions taken to prevent recurrence. routine event report was required in 2020.

Potential nonconformities are promptly addressed to maintain operations in compliance with plan requirements.

Plant personnel use a condition reporting process to document these conditions and track corrective actions to completion. Internal assessments, reviews and inspections are also used to ensure compliance.

Events that require notifications to federal, state or local agencies are reported in accordance with the applicable reporting requirements. The United States Nuclear Regulatory Photo courtesy of Greg McMullin Commission is provided with a copy of any such reports NO N- R O U T INE REP ORT REV IEW S This annual report also reviews non-routine reports submitted by plant personnel and any activities that involved a potentially significant unreviewed environmental question. A proposed change, test or experiment is considered to present an unreviewed environmental question if it concerns:

1. A matter that may result in a significant increase in any 2. A significant change in effluents or power level.

adverse environmental impact previously evaluated in the 3. A matter not previously reviewed and evaluated in Final Environmental Statement related to the Operation the documents specified in (1) above, that may have a of South Texas Project, Units 1 and 2 (Docket Nos. 50-498 significant adverse environmental impact.

and 50- 499), environmental impact appraisals, or in any decisions of the Atomic Safety and Licensing Board.

No unreviewed environmental questions were identified in 2020.

C H A PT E R FO U R l N O N - R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT ING R EPORT 4- 1 0

RADIOLOGICAL ENVIRONMENTAL INTRODUCTION &

SUMMARY

5-1 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

CHAPTER: FIVE The Radiological Environmental Monitoring Program is designed to evaluate the radiological impact of the South Texas Project on the environment by collecting and analyzing samples for low levels of radioactivity.

Measurements of samples from the different pathways indicate that there continues to be no adverse effect offsite from the operation of the South Texas Project.

Only tritium and naturally occurring radioactive material were identified in the offsite environmental samples in 2020.

Samples of fish and meat collected and analyzed showed Photo courtesy of Greg McMullin no South Texas Project related nuclides were present. Water samples from the onsite drinking water supply from the deep Photo courtesy of Greg McMullin aquifer and from offsite sampling stations on the Colorado River show only natural background radioactivity. The station Due to the design of the Main Cooling Reservoir, the also monitors for radioactivity in onsite sediment from the presence of tritium in various sloughs and ditches onsite and Main Cooling Reservoir and ditches. Measurements of direct the shallow aquifer is expected. Tritium has been detected radiation onsite and offsite indicated no federal dose limits in these types of samples and the concentrations remain were exceeded. below the United States Environmental Protection Agency drinking Tritium is a radioactive isotope of hydrogen that is produced water limits.

in the reactor and cannot be removed from effluents released to the Main Cooling Reservoir because it is part of the A sampling water molecule. program was developed to monitor the tritium in the immediate area around the plant for long term Photo courtesy of Greg McMullin trending. Wells are sampled either semi-annually, annually, or once every five years, depending on location and the amount of tritium present. The tritium concentration remained below the United States Environmental Protection Agency drinking water limits in 2020 and within the design basis of the South Texas Project.

Analyses of the data collected from the implementation of the Radiological Environmental Monitoring Program indicates Photo courtesy of Aubrey Passafuma that the operation of the South Texas Project has no adverse radiological impact.

Photo courtesy of Greg McMullin C H APT E R F I V E l R A D I O LO G I CA L E N V I R O N M E N TA L I N T R O D U CT I O N &

SUMMARY

5 - 2

RADIOLOGICAL ENVIRONMENTAL OPERATING REPORT 6-1 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

CHAPTER: SIX PROGRAM DESCRIPTION The South Texas Project initiated a comprehensive pre-operational Radiological Environmental Monitoring Program in July 1985. That program terminated on March 7, 1988, when the operational program was implemented. The data from the pre-operational monitoring program form the baseline against which operational changes are measured.

Analyses of the environmental pathways require that samples be taken from water, air, and land environments. These samples are obtained to evaluate potential radiation exposure Photo courtesy of Greg McMullin to people. Sample types are based on established pathways the control stations. Indicator stations are compared with and experience gained at other nuclear facilities. Sample characteristics identified during the pre-operational program locations were determined after considering site meteorology, to monitor for radiological effects from plant operation.

site hydrology, local demography, and land use. Sampling Two sample identification methods are used in the program.

locations are further evaluated and modified according to field Figures 6-1 and 6-2 are maps that identify permanent sample and analysis experience. Table 1 at the end of this section lists stations. Descriptions of sample stations shown on Figures the required sampling locations and frequency of collection.

6-1 and 6-2 are found in Table 2. Table 2 also includes Additional discretionary samples were also collected.

supplemental sampling locations and media types that may Sampling locations consist of indicator stations and control be used for additional information. Figure 6-3 illustrates zones stations. Indicator stations are locations on or off the site that that may be used to complement permanent, numbered may be influenced by plant discharges during plant operation. sample stations.

Control stations are located beyond the measurable influence Environmental samples from areas surrounding the South of the South Texas Project. Although most samples analyzed Texas Project continue to indicate no radiological effects are accompanied by a control sample, it should be noted from plant operation. Measured values from offsite indicator that this practice is not always possible or meaningful sample stations continue to trend with the control stations.

with all sample types. Fluctuations in the concentration of Measurements from onsite indicator samples continued to radionuclides and direct radiation exposure at indicator fluctuate within normal historical ranges.

stations are evaluated in relation to historical data and against Photo courtesy of Cheryl Bentley Photo courtesy of Rudy Perez CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 6-2

RAD I O LO G ICAL E NV I RO N M EN TA L M O N I TO RI N G P RO GR A M DE S I G NAT E D SA M P L E LO CATI O N M A P (Offsite locations are numbered)

Figure 6-1 6-3 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

R AD I O LO G ICAL E NV I R O N M EN TA L M O N I TO RI N G P RO GR A M O NS I T E SA M P L E LO CATI O N M A P Figure 6-2 CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 6-4

R AD I O LO G ICAL E NV I R O N M EN TA L M O N I TO RI N G P RO GR A M ZO N E LO CATI O N M A P Figure 6-3 6-5 STP ANNUAL ENVIRON M E N TAL OP E RAT I N G RE P ORT

A I R B O R N E PAT H WAY Average quarterly air particulate sample beta radiation activity from three onsite indicator stations and a single control station have been compared historically from 2001 through 2020 (see Figure 6-4). The average of the onsite indicators trends closely with the offsite control values. The comparison illustrates that plant operations are not having an impact on air particulate activity even at the Sensitive Indicator Stations (#1, #15, and #16). These stations are located near the site boundary downwind from the plant, based on the prevailing wind direction. The beta activity measured in the air particulate samples is from naturally occurring radioactive material. Gamma radiation analyses are performed on quarterly composites of the weekly air particulate samples to determine if any activity is from the South Texas Project. The gamma analyses revealed no radioactivity from the South Texas Project. Photo courtesy of Greg McMullin Figure 6-4 CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 6 - 6

D I R E C T E X P O S U R E PAT H WAY Direct gamma exposure is monitored in the environment with NNW, and N from the plants on FM 521 at Stations #15, #16 thermoluminescent dosimeters (TLDs) located at 40 locations and #1 respectively. The Indicator Stations are the remainder around the site. The natural direct gamma exposure varies of the required according to location because of differences in the natural monitoring radioactive materials in the soil, soil moisture content, and stations.

other factors. Figure 6-5 compares the amount of direct The values gamma exposure measured at the plant since the first quarter plotted are the of 2001 from three different types of stations. The South averages for Texas Project started using a vendor for offsite processing all the stations of the thermoluminescent dosimeters for environmental Photo courtesy of Aubrey Passafuma according to measurement of direct radiation during the third and fourth type. The average of the Control Stations is higher than the quarter of 2014. The Control Stations, Stations #23 and #37, other stations because Station #23 is in an area that has are greater than 10 miles from the site in the minimal wind slightly higher natural background radiation. The trends of direction. The prevailing wind direction was into the northwest Figure 6-5 show that South Texas Project is not contributing sector. The Sensitive Indicator Stations are one-mile NW, to the direct radiation in the offsite environment.

Figure 6-5 SEDIMENT SAMPLES The cobalt-60 inventory in the reservoir has decreased since and #216. In 2020, cobalt-60 was identified in three out of six 1992 because of radioactive decay and installed equipment Main Cooling Reservoir sediment samples taken, all results to reduce radioactive effluents. Although the total activity of were less than the reporting levels. Figure 6-7 demonstrates cobalt-60 has decreased over time, an inventory of cobalt-60 the calculated decline in the total amount of cobalt-60 in the is still in the reservoir as seen occasionally at Stations #215 reservoir. Bottom sediment samples are taken from the Main 6-7 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Cooling Reservoir each year. A study was performed in 2010 cobalt-60 remains. Figure 6-6 and Figure 6-7 show the results to locate the distribution and concentrations of cobalt-60 from the plant-produced cobalt-60 from the Main Cooling and cesium-137 in the Main Cooling Reservoir. Although Reservoir. One additional sample from onsite at Station 280, no cobalt-60 was detected from 2007 through 2010 at identified 40.1 pCi/kg of cobalt-60.

Stations #215 and #216, the concentration of cobalt-60 is Cesium-137 was measured in six out of six bottom sediment not uniformly distributed in the reservoir sediment and some samples from Stations #215 and #216 in the Main Cooling Figure 6-6 Figure 6-7 CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 6 - 8

Reservoir in 2020. The highest measurement was Station #216 in 2020 were 83.6 pCi/kg at Station #215. The highest measurement at slightly lower than previously Station #216 was 41.6 pCi/ kg. Cesium-137 is often found in detected due to sampling environmental media including soil and sediment as residual nonhomogeneous media.

radioactive material resulting from aboveground nuclear Results remained considerably weapons testing conducted in the 1950s and 1960s. Soil less than reportable levels.

and sediment samples taken in 1986 and 1987 prior to The measured values at operation of the South Texas Project contained cesium-137 Station #215 and #216 are from weapons testing. The average pre-operational consistent with pre-operational cesium-137 concentration was 118 pCi/kg in soil and concentrations reduced by 30 Photo courtesy of Greg McMullin sediment samples, andt the highest sample concentration years of radioactive decay.

was 383 pCi/kg. Cesium-137 activities measured at WAT E R B O R N E PAT H WAY Tritium has been detected in the shallow aquifer on the sout the remainder is released into the Main Cooling Reservoir.

side of the Main Cooling Reservoir since 1999. Models used The tritium escapes from the Main Cooling Reservoir by when licensing the site predicted tritium in the shallow aquifer. evaporation, movement into the shallow aquifer, and by These models were validated with additional studies in 2013. percolation from the relief wells which are a part of the A site conceptual model, developed in 2008 and updated in reservoir embankments stabilization system. Figure 6-8 2014, validated the original predictions of the site hydrology shows the amount of tritium released to the Main Cooling study. A revision was completed in 2018 to include Independent Reservoir each year and the amount present during the last Spent Fuel Storage Installation Project construction. quarter of each year.

Tritium is a radioactive isotope of hydrogen and is produced The concentration of tritium in the Main Cooling Reservoir in the reactors during plant operation. Wastewater is treated was relatively stable in 2020. The amount of tritium measured to remove impurities before release, but tritium cannot be in the Main Cooling Reservoir was consistent with the amount removed because it is chemically part of the water molecule. usually released to the reservoir. The amount of rainfall and Some of the tritium is released into the atmosphere and reservoir makeup from the Colorado River influences the concentration of tritium in the Main Cooling Reservoir and the shallow aquifer surrounding it. Tritium enters the sloughs and ditches of the site as runoff from the relief wells that surround the reservoir.

In 2020, tritium levels remained consistent with historical values in the relief wells as shown in Figure 6-9. Sampling of Main Cooling Reservoir relief well #701 has been discontinued due to no water flow at that location. Another existing Main Cooling Reservoir relief well #707, is now used as a representative substitute for sampling the relief well water from the Main Cooling Reservoir. Station #707 is Photo courtesy of Aubrey Passafuma just west of the discontinued relief well 6-9 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Figure 6-8 Figure 6-9 CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 1 0

Figure 6-10

1. 701 on the south side of the Main Cooling Reservoir. Due to reservoir precipitated in different flow rates of water through the relief wells, the base the local area. Tritium was concentration is slightly higher at relief well #707 compared not measured in any of the to #701. The highest 2020 sample from relief well #707 rainwater samples offsite.

indicated approximately 5,845 pCi/kg, which is less than Tritium was identified in the required reporting levels.

shallow (i.e. ten to thirty feet The tritium concentrations in eight surface water sample deep) aquifer test wells at Photo courtesy of Greg McMullin locations from 2001 through 2020 are shown in Figure Station #235 approximately 6-10. The specific sample point locations can be found in seventy-five yards south of the reservoir embankment base Table 2. Tritium levels in the onsite sloughs and ditches vary during 1999. Starting in 2000, samples were collected with the concentration from the shallow aquifer well at Station #251 south of the in the reservoir and Main Cooling Reservoir. The tritium results from these two the amount of rainfall shallow aquifer wells are shown in Figure 6-11. In 2020, the received. The average concentration of tritium at Station #235 was consistent with tritium concentration in values over the past ten years.

the relief well, sloughs, Shallow aquifer tritium concentrations have remained near the and ditches are less than concentrations found in the relief wells. Wells at Stations #258 Photo courtesy of Aubrey Passafuma the reservoir because the and #259 on the west side of the site boundary have been water is diluted as it migrates through the reservoir relief well sampled since 2006. Wells at Stations #270 and #271 were system. In 2020, eleven out of twelve surface water sample installed during the last quarter of 2008. The sample results locations tested positive for tritium. All test results were below are shown in Figure 6-12. The well at Station #271, located the United States Environmental Protection Agency drinking adjacent to site property on a county road easement directly water limit of 20,000 pCi/kg. Rainwater was collected and west of the Main Cooling Reservoir, indicated its highest analyzed during 2020 to determine if the tritium from the 6-11 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

concentration for 2020 at 4,329 pCi/kg. In 2020, a maximum approximately 620 millirem value of 5,601 pCi/ kg was identified for onsite test wells. the public receives a year Tritium levels continued to remain below the United States from natural radioactivity Environmental Protection Agency drinking water limit in the environment and (20,000 pCi/kg). the radiation received from medical procedures.3 Tritium has not been detected in the deep aquifer that is the source of drinking water for the local communities and Other samples are homes. These measurements follow the hydrological model collected and analyzed in described in the original license basis and the updated site addition to those required conceptual model discussed earlier in this section. by our licensing documents Photo courtesy of Greg McMullin or internal procedures.

A windmill-powered well, Station #267, indicated 519 These samples are collected to give additional assurance pCi/kg in 2020. This onsite ground water sample station is that the public and the environment are protected from the most distant location from the Main Cooling Reservoir any adverse effects from the plant. These samples include that tritium has been detected. This well is not used for pasture grass, sediment samples, rainwater, shallow aquifer human consumption.

well, water from various ditches and sloughs onsite, direct The drinking water onsite is pumped from deep aquifer radiation, and air samples near communities or other areas wells and is collected monthly and composited quarterly to of interest. The results of these analyses indicate that plant verify tritium is not present. The South Texas Project does operation has no health impact offsite and is well within state not use water from the reservoir, shallow aquifers or other and federal regulations and guidelines.

surface water for drinking. If the water with the highest tritium concentration that leaves the site was used for drinking, 3 NCRP (2006). National Council on Radiation Protection and the maximum dose to an individual would be less than one Measurements, Ionizing Radiation Exposure of the Population of millirem in a year. This dose is insignificant compared to the the United States, (Bethesda, Maryland), NCRP Report No. 160.

Figure 6-11 CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 1 2

Figure 6-12 N E I G R O U N D WAT E R P R OT E C T I O N I N I T I AT I V E In 2007, the Nuclear Energy Two wells sampled annually (Stations #807 and #808)

Institute (NEI) established a are adjacent to where a pipe was damaged and repaired standard for monitoring and several years ago. The tritium concentration at these two reporting radioactive isotopes wells continued to decrease as expected in 2020. Station in groundwater entitled NEI #809 tritium concentrations were related to the previously Groundwater Protection referenced pipe and subsequent repair. All the other wells Initiative, NEI 07-07. The sampled in 2020 that had detectable tritium are influenced by station implemented the recommendations of this industry standard and has broadened the groundwater Photo courtesy of Greg McMullin monitoring program to include additional samples collected near the plants. Some of the positive results of this broadened monitoring program reflect tritium associated with the Main Cooling Reservoir.

Wells near the plants are sampled semi-annually, annually, or once every five years depending on the concentration of tritium anticipated and the location of the wells. Wells with high concentrations are sampled more frequently. Figure 6-13 contains the 2020 results for wells that were sampled along with the historical highs measured prior to 2020 for each station since sampling began in 2006. Their locations are shown in Figure 6-14. Photo courtesy of Roger Dement 6-13 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

STP Protected Area Ground Water Monitoring Results Note: All measurements are reported in pCi/kg for increased accuracy and are equivalent to pCi/L for reporting purposes.

Figure 6-13 STP Protected Area Ground Water Monitoring Wells Figure 6-14 CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 1 4

groundwater originating in the Main Cooling Reservoir. Their concentrations remain in the range of groundwater tritium concentrations associated with the Main Cooling Reservoir.

All the 2020 measurements of tritium in groundwater are a small fraction of the United States Environmental Protection Agency drinking water limit (20,000 pCi/kg).

During 2012, steam traps for the auxiliary steam system that could potentially contain trace amounts of tritium were modified to re-direct the condensed steam or liquid water to the Main Cooling Reservoir. Information regarding the steam traps and subsequent response was documented in the Photo courtesy of Greg McMullin stations condition reporting process. of the protected area wells had undergone a modification to enhance the protection of the structural integrity of the This evaluation water well casing used for sampling the upper aquifer.

identified no new The modifications were completed in 2015 with continued effuent release improvements into 2016.

pathways and no impact to the drinking In 2020, there was one occurrence where condensed water or the health steam or water contacted the ground onsite. None of and safety of these occurrences resulted in impact to the public or the the public. environment. No discharge occurred offsite or to groundwater that may be used as a source of drinking water. Where By the end of applicable, the water was quickly recovered, recaptured, and Photo courtesy of Greg McMullin 2014, the majority clean up completed with no impact to groundwater.

Photo courtesy of Ronnie Ormand 6-15 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

LAND USE CENSUS The Annual Land Use Census is performed to determine if that have residents within five miles and the distance to the any changes have occurred in the location of residents and nearest residence in each sector are listed below.

the use of the land within five miles of the South Texas Project generating units. The information is used to determine whether any changes are needed in the Radiological Environmental Monitoring Program. The census is performed by contacting local government agencies that provide the information.

In addition, a survey is performed to verify the nearest residents within five miles of the South Texas Project generating units in each of 16 sectors. The results of the survey indicated no changes for 2020. The eleven sectors Photo courtesy of Aubrey Passafuma L AND U SE CENSU S ITEMS OF INTEREST

• No commercial dairies operate * One commercial fish farm * There were no identified within Matagorda County. continues to operate. It is located commercial vegetable farms approximately four to five miles located within the five-mile zone.

• There were no identified animals southwest of the plant located in producing milk for human * Broadleaf vegetation sampling is the area north of Robbins Slough consumption located within five performed at the site boundary Road and east of South Citrus miles of STP. in the three most leeward sectors Grove Road. The water supply for and at a control location in lieu of

• A commercial olive tree orchard is the ponds is not affected by the a garden census. The broadleaf located approximately 4.9 miles operations of the South Texas vegetation samples collected also WSW of the plant. Project.

satisfy the collection requirement

• Colorado River water from below when milk samples are not the Bay City Dam has not been available.

used to irrigate crops.

CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 1 6

Figure 6-15 Figure 6-16 6-17 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

QUALITY ASSURANCE Quality assurance encompasses planned and systematic provides samples that actions to ensure that an item or facility will perform are similar in matrix and satisfactorily. Reviews, surveillances, and audits have size to those measured determined that the programs, procedures and personnel by the Radiological are performing at a Environmental Monitoring satisfactory level. Program. This program assures that equipment Quality audits and calibrations and sample independent technical preparation methods reviews help to determine accurately measure areas that need attention.

radioactive material in These areas are addressed samples. Figure 6-15 in accordance with the summarizes the results stations Condition Reporting of the interlaboratory Process.

Photo courtesy of Joe King comparison programs.

Photo courtesy of Joe King The measurement Duplicate sampling of the environment allows the South Texas capabilities of the Radiological Laboratory are demonstrated Project to estimate the repeatability of the sample collection, by participating in an interlaboratory measurement assurance preparation, and analysis process. Splitting samples allows program as well as performing duplicate and split sample estimation of the precision and bias trends of the method of analyses. Approximately 21.7 percent of the analyses analysis without the added variables introduced by sampling.

performed are quality control samples. These consist of Generally, two samples split from the same original sample interlaboratory measurement assurance program samples, material should agree better than two separate samples duplicate samples, and split samples.

collected in the same area and time. The 2020 variances for The interlaboratory measurement assurance program duplicates and splits are shown in Figure 6-16.

P R O G R A M D E V I AT I O N S In addition to measurement accuracy, radiochemical measurements must meet sensitivity requirements at the Lower Level of Detection for environmental samples.

Deviations from the sampling program or sensitivity requirements must be acknowledged and explained in this report. The loss of a small fraction of the total samples collected in 2020 did not impact the ability to demonstrate that the South Texas Project continues to operate with no negative effect on the population or the environment.

During 2020 samples not collected or unacceptable for analysis:

• One out of 265 Offsite Dose Calculation Manual (ODCM) required radioiodine samples was not collected due to loss of power from station #16.

• Three air samples not required by the ODCM from station Photo courtesy of Greg McMullin

1. 39 were not continuously collected for the full-time interval January due to weather conditions, since this sample because of power or equipment failures. is outside the growing season it was not required by

• One broadleaf vegetation sample was not collected in the ODCM.

CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 1 8

TA B L E 1 R A D I O LO G I C A L E N V I R O N M E N TA L M O N I TO R I N G P R O G R A M MCR-STP Main Cooling Reservoir STP- South Texas Project 6-19 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

TA B L E 1 R A D I O L O G I C A L E N V I R O N M E N TA L M O N I T O R I N G P R O G R A M ( C O N T. )

MCR-STP Main Cooling Reservoir STP- South Texas Project CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 6- 2 0

TA B L E 1 R A D I O L O G I C A L E N V I R O N M E N TA L M O N I T O R I N G P R O G R A M ( C O N T. )

Photo courtesy of Greg McMullin 6-21 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 2 2 TA B L E 2 S A M P L E M E D I A A N D LO C AT I O N D E S C R I P T I O N S 6-23 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

TA B L E 2 S A M P L E M E D I A A N D L O C AT I O N D E S C R I P T I O N S ( C O N T. )

This station may be used to obtain the required aquatic samples in the vicinity of STP that may be influenced by plant operations.

MCR-STP Main Cooling Reservoir STP- South Texas Project Media codes typed in bold satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

• Control Station CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 2 4

TA B L E 2 S A M P L E M E D I A A N D L O C AT I O N D E S C R I P T I O N S ( C O N T. )

This station may be used to obtain the required aquatic samples in the vicinity of STP that may be influenced by plant operations.

MCR-STP Main Cooling Reservoir STP- South Texas Project Media codes typed in bold satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

• Control Station 6-25 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

TA B L E 2 S A M P L E M E D I A A N D L O C AT I O N D E S C R I P T I O N S ( C O N T. )

This station may be used to obtain the required aquatic samples in the vicinity of STP that may be influenced by plant operations.

MCR-STP Main Cooling Reservoir STP- South Texas Project Media codes typed in bold satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

• Control Station CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 2 6

TA B L E 2 S A M P L E M E D I A A N D L O C AT I O N D E S C R I P T I O N S ( C O N T. )

This station may be used to obtain the required aquatic samples in the vicinity of STP that may be influenced by plant operations.

MCR-STP Main Cooling Reservoir STP- South Texas Project Media codes typed in bold satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

• Control Station 6-27 STP ANNUAL ENVIR ON M E N TAL OP E RAT I N G RE P ORT

R A D I O LO G I C A L E N V I R O N M E N TA L M O N I T O R I N G P R O G R A M A N A LY S I S S U M M A R Y A summary of all required samples is given in Table 3. The * The number of table has been formatted to resemble a United States Nuclear positive measure-Regulatory Commission industry standard. Modifications have ments / the total been made for the sole purpose of reading ease. Only positive number of analyses values are given in this table. * The lowest and highest values for Media type is printed at the top left of each table, and the units the analysis of measurement are printed at the top right. The first column lists the type of radioactivity or specific radionuclide for which The data placed in Photo courtesy of Greg McMullin each sample was analyzed. The second column gives the Table 3 are from the samples required by the sites Offsite total number of analyses performed and the total number of Dose Calculation Manual as described in Table 1. Additional non-routine analyses for each indicated nuclide. A nonroutine thermoluminescent dosimeters were utilized each quarter measurement is a sample whose measured activity is greater for quality control than the reporting levels for Radioactivity Concentrations in purposes. The Environmental Samples. The LOWER LIMIT OF DETECTION minimum samples column lists the normal measurement sensitivities achieved. required by Table 1 The sensitivities were better than required by the United States were supplemented Nuclear Regulatory Commission. in 2020 by numerous direct radiation A set of statistical parameters is listed for each radionuclide in measurements, the remaining columns. The parameters contain information additional surface Photo courtesy of Greg McMullin from the indicator locations, the location having the highest water samples, ground water samples, additional pasture annual mean, and information from the control stations. Some grass, additional rainwater samples, additional relief well water samples, and additional sediment samples. Fish and crustacean samples vary in number according to availability, but exceeded the minimum number required by Table 1, as well as other meat samples. Also, Photo courtesy of Greg McMullin numerous air station samples were collected from weekly air sample stations, in addition to the minimum number of samples required by Table 1 to strengthen the Radiological Environmental Monitoring Program.

The minimum required Radiological Environmental Monitoring Program is presented in Table 1. The table is organized by Photo courtesy of Aubrey Passafuma exposure pathway. Specific requirements such as location, sample types do not have control stations. When this is the sampling method, collection frequency, and analyses are given case, no samples is listed in the control location column. for each pathway.

• For each of these groups of data, the following is calculated:

• The mean positive values CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 2 8

Photo courtesy of Aubrey Passafuma 6-29 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Aubrey Passafuma CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 3 0

Photo courtesy of Greg McMullin 6-31 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Greg McMullin CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 3 2

Photo courtesy of Aubrey Passafuma 6-33 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Aubrey Passafuma CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I NG R EPORT 6- 3 4

Photo courtesy of Greg McMullin Photo courtesy of Aubrey Passafuma Photo courtesy of Aubrey Passafuma 6-35 STP ANNUAL ENVIRON M E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Christie Dement CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 3 6

Photo courtesy of Rudy Perez Photo courtesy of Rudy Perez Photo courtesy of Greg McMullin Photo courtesy of Greg McMullin 6-37 STP ANNUAL ENVIR ONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Aubrey Passafuma CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 3 8

Photo courtesy of Aubrey Passafuma 6-39 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Greg McMullin CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 4 0

Photo courtesy of Christie Dement 6-41 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Rudy Perez CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 4 2

Photo courtesy of Greg McMullin 6-43 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Photo courtesy of Aubrey Passafuma CH A PT E R S I X l R A D I O LO G I CA L E N V I R O N M E N TA L O P E R AT I N G R EPORT 6- 4 4

Photo courtesy of Susan Branson 6-45 STP ANNUAL ENVIR ONM E N TAL OP E RAT I N G RE P ORT

The sculpture in front of the Nuclear Support Center was created by South Texas Artist James Phillips in honor of the men and women whose hard work and dedication have contributed to over 30 years of Excellence at STP.

The sculpture was carved from a live oak tree trunk donated by Chief Financial Officer George Harrison into a unique design to honor our history.

Photo courtesy of Greg McMullin