ML22116A233

Annual Environmental Operating Report

ML22116A233
Person / Time
Site:	South Texas
Issue date:	04/26/2022
From:	Stone C South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-22003887
Download: ML22116A233 (71)

Text

Nuclear Operaitng Corrspany South Texas Project Electric Generating Station P.O. Box 289 Wadsworth. Texas 77483 April 26, 2022 NOC-AE-22003887 10CFR50.36b STI: 35307197 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 2021 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 2021 Annual Environmental Operating Report.

There are no commitments in this letter.

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

Clayton B. Stone Manager, Health Physics

Attachment:

2021 Annual Environmental Operating Report ec:

Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 1600 E. Lamar Boulevard Arlington, TX 76011-4511

S OUTH TEXAS PROJECT ELECTRIC GENERATING STATION 2021 ANNUAL ENVIRONMENTAL OPERATING REPORT

The 2021 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 2022 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 2021 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 Coordination and support by Corporate Communications STP ANNUAL ENVI RONM E N TAL OP E RATI 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8 Waterborne Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10 NEI Groundwater Protection Initiative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13 Land Use Census. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15 Quality Assurance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16 Program Deviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18 Radiological Environmental Monitoring Program Analysis Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-30 LIST OF FIGURES Figure 2-1: Plant Water Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 Figure 4-1: 2021 Non-radioactive Waste Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7 Figure 4-2: 2021 Non-radioactive 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. . . . . . . . . . . . . . 6-9 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: 2021 Radiological Laboratory Quality Assurance Program Performance . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 Figure 6-16: Duplicate & Split Agreement of Environmental Samples in 2021 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17 L I S T O F TA B L E S Table 1: Radiological Environmental Monitoring Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20 to 6-22 Table 2: Sample Media and Location Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 to 6-28 Table 3: 2021 Radiological Environmental Monitoring Program Analysis Summary. . . . . . . . . . . . . . . . . . . . . . 6-31 to 6-40

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 Gary Parkey M E S SAG E F R O M T H E P R E S I D E N T 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 monitoring encompasses, as a minimum, (South Texas Project) continues to operate with no water quality, air quality, waste generation and minimization, adverse effect on the population or the environment. and local aquatic and terrestrial ecological conditions. In The dose equivalent for people living in the area 2021, non-radiological remains at less than one millirem per year. monitoring by the Environmental programs at the site monitor known station confirmed and predictable relationships between the operation that the South Texas of the South Texas Project and the surrounding area. Projects efforts to These monitoring programs verify that the operation respect and protect of the South Texas Project has no impact offsite local environmental and is well below state and federal regulations and conditions were guidelines. These programs are verified by the State of successful. The Photo courtesy of Greg McMullin Texas through collection and analysis of samples and operation of South placement of the States monitoring dosimeters and Texas Project continued to provide high-quality habitat other onsite and offsite inspections. areas for a variety of flora and fauna and continued to have no indications of negative non-radiological impacts to local This report describes the environmental monitoring environmental conditions.

programs, non-radiological and radiological, conducted at the South Texas Project during 2021. Included in this report The environment within a 15-mile radius of the South Texas are the Environmental Protection Plan Status, the results of Project is routinely monitored for radiation and radioactivity.

the Radiological Environmental Monitoring Program, and the Sampling locations are selected using weather, land use, Land Use Census. and water use information. Two types of sampling locations are used. The first type, Control Stations, are located in Non-radiological environmental monitoring is performed areas that are beyond the measurable influence of the each year as part of the stations overall Environmental South Texas Project or any other nuclear facility. The sample Protection Plan which is intended to provide for protection results from these stations are used to explain radiation of non-radiological environmental parameters during from sources other than the South Texas Project. Indicator station operations.

Stations are the second type of station. The samples from Photo courtesy of Greg McMullin Photo courtesy of Rudy Perez CH A PT E R 0 N E l E X E CU T I V E

SUMMARY

1 - 2

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 dose equivalent for people living in the area is maintained at less than one millirem per year. Environmental programs at the site monitor known and predictable relationships between the operation of the South Texas Project and the surrounding area. These monitoring programs verify that the operation of the South Texas Project has no impact Photo courtesy of Greg McMullin offsite and is well within state and federal regulations and these stations measure any radiation contributed to the guidelines. These programs are verified by United States environment that could be caused by the South Texas Nuclear Regulatory Commission inspections and the State Project. Indicator Stations are located in areas close to the of Texas through collection and analysis of samples and South Texas Project where any plant releases would be detected.

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.

Radioactivity levels in the South Texas Projects environment frequently fall below the minimum detection capabilities 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 Photo courtesy of Christi Dement equal to or greater than this reporting level. No sample from the South Texas Project has ever reached or exceeded this reporting level. Measurements performed are divided into state radiation monitoring dosimeters.

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

• The 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 2021 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 2021. Tritium levels results are consistent with the readings from previous years 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

1 - 4

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 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.

Photo courtesy of Greg McMullin The South Texas Project has two Westinghouse pressurized licenses an additional twenty years through 2047 and 2048.

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

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

heat to convert water into high-pressure steam. The steam The fuel for a nuclear reactor is uranium. It is formed into cylindrical ceramic pellets, each about the size of the end of your little finger. One pellet has the energy potential of about a ton of coal. Millions of these pellets are stacked in fuel rods that are arranged into assemblies that make up the core of the reactor. The use of uranium allows us to conserve natural gas, oil, and coal and to avoid the associated production of greenhouse gases. The fission process and generation of usable heat begins in a nuclear Photo courtesy of Rudy Perez reactor when control rods in the core are withdrawn. In pressurized water reactors, like those at the South Texas Project, the fuel rods heat water circulating in sealed, Photo courtesy of Greg McMullin stainless steel piping that passes through large heat exchangers called steam generators. The water in the is directed through a turbine to turn a generator. In a fossil reactor is under pressure to prevent boiling. This is why fuel plant, either coal, lignite, oil, or natural gas is burned in the South Texas Projects Units 1 and 2 reactors are called a boiler to produce the heat. In a nuclear plant, the reactor pressurized water reactors.

CH A PT E R T WO l S I T E A N D A R E A D ES C R IPT ION 2 - 2

PLANT WATER SYSTEMS Figure. 2-1 This hot, pressurized water heats a separate supply of water Nuclear energy has one of in the steam generators to produce steam that is directed the lowest impacts on the through the blades of a turbine generator to produce environment. It is the most electricity. The steam is then fed to a condenser where a eco-efficient energy source separate supply of cooling water from the Main Cooling because it produces the Reservoir condenses it back into water that is then pumped most electricity in relation back to the steam generator for reuse. A diagram of the to its minimal environmental plant water systems is shown in Figure 2-1. impact. In 2019, the most recent year for which data is In addition to its safety Photo courtesy of Kelly Callais available, nuclear generation systems, the South Texas in the United States prevented 506 million metric tons of Project has many built-in carbon dioxide, 0.27 million short tons of sulfur dioxide, and physical barriers designed 0.24 million short tons of nitrogen oxide from entering the to prevent the release of Earths atmosphere.1 Nuclear power plants also generated radioactive materials in approximately 55 percent of the emission-free electricity the unlikely event of an generation in the United States in 2019.1 Additional accident. The most visible information on nuclear energy and the environment can ones are the 200-foot be found on the website maintained by the Nuclear Energy tall, domed containment Photo courtesy of Rudy Perez Institute at www.nei.org.

buildings with steel reinforced concrete walls four feet thick. Inside each of 1 Nuclear Energy Institute. Nuclear by the Numbers; August these massive structures, two more concrete walls provide 2020. As viewed at www.nei.org/CorporateSite/media/

another 11 feet of radiation shielding. The reactor vessel filefolder/resources/ fact-sheets/nei-nuclear-by-the-numbers-itself has steel walls six inches thick, and the fuel pellets 092520-final.pdf.

inside it are sheathed in hardened metal tubes.

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 habitat. A 110-acre wetland habitat area was established Project are occupied by the two current power plants. Plant in 1996 on previously unused land located northeast of the facilities include a 7,000-acre main cooling reservoir and power plants. The area surrounding the South Texas Project a 47-acre essential cooling pond. Many smaller bodies of is characterized by coastal plain with farmland and pasture water onsite include wetlands, Kelly Lake, drainage ditches, predominating. Local relief of the area is characterized by sloughs, and depressions. Much of the land east of the flat land, approximately 23 feet above sea level.

cooling reservoir is leased for cattle grazing. Approximately 1,700 acres remain in a more natural state as a lowland THE AREA Matagorda Countys economy is based primarily on The South Texas Project is home to many species of ranching, farming, oil and natural gas production and animals. Inhabitants include American alligators, a variety of refinement, petrochemical production, electricity generation, birds, and several hundred deer. In winter, literally hundreds and commercial fishing and fisheries. The area within of thousands of waterfowl, principally migratory geese as 10 miles of the site is generally rural and characterized well as white pelicans, have found that the plants 7,000-as farmland, which is primarily pastureland used for acre cooling reservoir provides a good resting place during livestock ranching. Although the surrounding area is heavily their migrations.

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

from the south-southeast, shifting to north-northeast for short intervals during the winter months.

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

NON-RADIOLOGICAL ENVIRONMENTAL INTRODUCTION AND

SUMMARY

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

CHAPTER: THREE Non-radiological environmental conditions and performance at the South Texas Project during 2021 remained satisfactory and demonstrated that the South Texas Project continued to operate in an environmentally responsible manner during the year.

The South Texas Project achieved and maintained high standards of environmental performance and compliance throughout 2021.

The South Texas Project is committed to the production of electricity in a safe, reliable, and economical manner using nuclear energy. The stations programs, policies, and business plan objectives also incorporate a commitment to environmental protection and management. The stations commitment to sound environmental management in 2021 is illustrated below.

Everyone at the South Texas Project has a responsibility to protect the environment. Commitment to environmental safety is an integral component of the South Texas Project operating policy and core values. This responsibility reaches further than mere compliance with laws and regulations to encompass the integration of sound environmental practices into our daily operational and business decisions. The people at the South Texas Project understand the need to balance economic, operational, and environmental issues for the benefit of the station and the public. We recognize our responsibility to hold ourselves to the highest principles of environmental stewardship.

Photo courtesy of Rudy Perez THE STATIONS COMMITMENT TO S OUND ENVIRONMENTAL MANAGEMENT IN 2021

• Satisfactory performance * Continued emphasis on waste * Completion of a wastewater classification2 by the Texas minimization and source reduction inspection by the Texas Commission on Environmental allowing the station to maintain Commission on Environmental Quality based on the stations its classification as a small quantity Quality with no violations or environmental compliance record generator of industrial waste. findings identified.

in all areas considered, including water quality, waste management, Photo courtesy of Rudy Perez and air quality compliance.

Per Compliance History Report for CN601658669, RN102395654, Rating Year 2021; as prepared by the Texas Commission 2

on Environmental Quality.

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

3 -2

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 wildlife and occupies approximately 1,700 acres of the site Projects non-radiological environmental program near the Colorado River. An upland spoil containment area, performance and environmental conditions for 2021. originally constructed in 1972 by the United States Army The STP Nuclear Operating Company employees Corps of Engineers, is included in this area. In addition, closely monitor environmental conditions at the South a 110-acre wetland habitat area that attracts a variety of Texas Project. NRG Energy, Inc. provides support and bird groups and other wildlife was established in 1996 on technical assistance to the South Texas Project. previously unused land located northeast of the power plants. The remaining area of the site offers diverse habitats The Texas Commission on Environmental Quality rated the for mammals and several types of birds. The South Texas South Texas Project as a satisfactory performer in 2021 Project regularly monitors the sites environs for changing based on the stations environmental compliance record.

conditions. Ecological conditions onsite in 2021 remained Facilities, such as the South Texas Project, can be classified generally unchanged and stable.

by the state as a high performer, satisfactory performer, or 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 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 and white) have been observed during informal surveys of the sites diverse natural and man-made habitats.

Photo courtesy of Greg McMullin Intensive bird nesting continues throughout the lowland unsatisfactory performer based on that facilitys compliance habitat, particularly in a heron rookery around the perimeter history. The states classification of the South Texas Project of Kelly Lake and on the internal dikes of the Main Cooling as a satisfactory performer was based on the stations Reservoir at the South Texas Project. The South Texas environmental performance over the last five-year period. Project continues to provide vital habitat for more than an estimated 125 species of wintering and resident birds.

During the period of this report, the station continued to promote green initiatives including the recycling of paper, plastics, and aluminum by site employees. The station also continued to support various bird counts and surveys in 2021 sponsored by federal and state agencies and volunteer organizations such as the annual National Audubon Society Christmas Bird Count and the United States Fish and Wildlife Services Colonial Waterbird Survey.

Photo courtesy of Greg McMullin AQUATIC AND ECOLOGICAL MONITORING The location of the South Texas Project falls within the Texas Land Resource Area designation as coastal prairie and can be divided into two broad ecological areas - bottomland and upland areas - based on topography, soils, and vegetation.

The bottomland lowland habitat is a swampy, marshy area that provides an important habitat for birds and other Photo courtesy of Greg McMullin C H APT 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 N G R EPORT 4 - 2

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 98 percent of the water used at the South Texas Project in 2021.

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

The South Texas Project continues to monitor important wildlife species to detect population changes. Informal Most of the water used by the South Texas Project is observations continue to indicate that the site provides needed to condense steam and provide cooling for plant high-quality habitat in which a wide range of animals thrive. generating systems. The majority of this water is drawn The site continues to attract extensive wildlife populations, from and returned to the stations Main Cooling Reservoir.

offering a refuge for resident species as well as seasonal The Main Cooling Reservoir is a 7,000-acre, above grade, migrants. The lowland habitat located between the Colorado off-channel reservoir capable of impounding 202,600 River and the east bank of the Main Cooling Reservoir offers acre-feet of water at its maximum level. Water is diverted a significant source of water year-round. These natural intermittently from the adjacent Colorado River to replenish resource areas, in concert with numerous additional wetland the Main Cooling Reservoir. In addition, the Essential and grassland areas, offer the key ingredients necessary Cooling Pond, a 47-acre, below grade, off-channel reservoir to sustain the extensive wildlife population at the South Texas Project.

WATER QUALITY MANAGEMENT Water is an essential component in electricity production, and electric utilities must comply with extensive federal, state, and local water regulations. These regulations govern virtually every aspect of business operations at the South Texas Project. Water usage, wastewater treatment onsite and certain maintenance and repair activities are regulated under the Safe Drinking Water Act, the Federal Clean Water Act, and the Texas Water Quality Act. Collectively, these Acts provide for the safeguarding of public drinking Photo courtesy of Greg McMullin water supplies and maintaining the integrity of state and that supplies water to cool crucial plant components, is federal waters. Regulating agencies that administer these capable of impounding 388 acre-feet of water. Various water requirements include the United States Army Corps of rights permits, contractual agreements, and compliance Engineers, the United States Environmental Protection documents authorize the South Texas Project to maintain Agency, the Texas Commission on Environmental these reservoirs, impound water diverted from the Colorado Quality, the Texas General Land Office the Lower Colorado River, and to circulate, divert, and use water from the River Authority, and the Coastal Plains Groundwater reservoirs for industrial purposes to operate the plant.

Conservation District.

These authorizations also limit the amount and rate of The South Texas Project uses both surface water and diversion from the Colorado River to protect downstream groundwater for station purposes. Consistent with the environmental flow requirements for bays and estuaries. The stations environmental principles encouraging efficient water South Texas Project diverted 79,715 acre-feet in 2021 from 4-3 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

the Colorado River for Main Cooling Reservoir fill operations state and federal water quality standards during the year, while preserving adequate freshwater flow conditions for while conserving and maximizing efficient water usage at downstream bay and estuarine ecosystems. Approximately the South Texas Project. In addition to the wastewater 1,329 acre-feet of the water used by the station was discharge permit program, the Federal Clean Water Act, withdrawn from onsite groundwater sources in 2021. as amended, requires permits for storm water discharges associated with industrial activity. The South Texas Projects Existing federal and state water quality standards are Storm Water Pollution Prevention Plan ensures that implemented and enforced through the Texas Pollutant potential pollution sources at the site are evaluated and that Discharge Elimination System (TPDES) permit program appropriate measures are selected and implemented to to restore and maintain the states waters. Under this permit program, the South Texas Project monitors, records, and reports the types and quantities of pollutants from wastewater discharges to ensure that the South Texas Project meets the stringent levels set in the permit. The TPDES permit was renewed in 2020. A monthly monitoring report is submitted to the Texas Commission on Environmental Quality for wastewater discharges.

In 2021, the Texas Commission on Environmental Quality conducted an extensive onsite wastewater inspection. No findings or violations were identified during the inspection.

Reports identifying groundwater use, surface water use, and water conservation are submitted annually to the Texas Water Development Board.

Reports of surface water diversion and consumptive use are submitted to the Texas Commission on Environmental Quality and the Lower Colorado River Authority. An annual groundwater use report is also submitted to Photo courtesy of Lee Rahrlien the Coastal Plains Groundwater prevent or control the discharge of pollutants in storm water Conservation District in accordance with groundwater runoff. This plan is a document that is revised whenever district requirements.

there is a change in design, construction, operation, or Wastewater generated at the South Texas Project is maintenance that has a significant effect on the potential for processed and discharged to the onsite Main Cooling the discharge of pollutants from the station. The stations Reservoir to be re-used by the station as cooling water Multi-Sector General Permit for storm water discharges was for plant systems. No water was discharged from the renewed in 2021.

Main Cooling Reservoir in 2021 other than from the Following a severe drought in 1996, the Texas Legislature relief wells that are part of the reservoir embankment recognized the need to address a wide range of state water stabilization system. No aquatic monitoring was required resource management issues. In 1997, the Texas Senate to be conducted at the site in 2021 by the United States drafted legislation known as Senate Bill 1 to address these Environmental Protection Agency or the Texas Commission issues and to develop a comprehensive state water policy.

on Environmental Quality. Wastewater discharges met The legislation required the Texas Water Development C H APT 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 N G R EPORT 4 - 4

with the enactment of Senate Bill 2. Accordingly, the Coastal Plains Groundwater Conservation District, encompassing Matagorda County, was confirmed by local election in late 2001. The purpose of the district is to manage and protect the groundwater resources of the district. The South Texas Project groundwater wells are registered with the Coastal Plains Groundwater Conservation District. Operating permits for the groundwater wells were renewed in 2020, as required every three years.

Station personnel continue to monitor onsite groundwater usage according to the requirements of Photo courtesy of Greg McMullin District rules. Additional information regarding the Coastal Board to create a statewide water plan that emphasizes Plains Groundwater Conservation District can be found regional planning. Sixteen planning regions were created, on its website at www.coastalplainsgcd.com. In 2007, in each tasked to prepare a plan for the orderly development, further recognition of the importance of water conservation management, and conservation of water resources. The to meet future demands in the state, Senate Bill 3, enacted South Texas Project was chosen to represent the interests by the Texas Legislature, created a stakeholder-driven of electric generating utilities for water-planning Region process for the development of environmental flows.

K, encompassing the lower Colorado River Basin. A state Environmental flows are the amount of water necessary water plan is prepared by the Texas Water Development Board every five years based on the regional water plans.

The regional water plans are revised each planning cycle based on updated population and water demand projections, water supply analyses, and water management strategies for a 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 in January 2021. The South Texas Project continues to actively participate in the Lower Colorado Regional Water Planning Group to identify Photo courtesy of Gary Parkey strategies to meet future water supply demand projections for the region and to update the existing plan accordingly. for a river, estuary, or other freshwater system to maintain Additional information regarding regional water planning in its health and productivity. The law established a process Texas can be found on the website maintained by the Texas to develop environmental flow regime recommendations Water Development Board at www.twdb.texas.gov. for each major river basin in Texas. The process tasked a Senate Bill 1 also required groundwater conservation team of stakeholders from each area of the state, working districts to develop groundwater management plans with with a science team, to develop a set of recommendations estimates on the availability of groundwater in the district, to the Texas Commission on Environmental Quality and to details of how the district would manage groundwater, perform ongoing periodic reviews of the recommendations.

and management goals for the district. The water planning The South Texas Project participated as a member of the and management provisions were further clarified in 2001 stakeholder committee that included the Colorado River and 4-5 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

Matagorda Bay. The The process started in 2019 when the Lower Colorado environmental flow River Authority submitted an updated Water Management standards set flow Plan to the Texas Commission on Environmental Quality levels at various points for approval. The South Texas Project participated in the in rivers and streams development of the revision for presentation to and approval to protect water in the by the Texas Commission on Environmental Quality.

rivers and estuaries Stakeholders included representatives from cities, industry, along the coast. The lake area businesses and residents, environmental interests, existing South Texas and agriculture. Additional information on the Lower Project right to divert Colorado River Authority Water Management Plan can be surface water was found at www.lcra.org.

not impacted by this In 1999, the South Texas Project implemented a station Photo courtesy of Christie Dement legislation. Additional Water Conservation Plan in accordance with state water information regarding environmental flows can be found at use regulations. The purpose of the Water Conservation www.tceq.texas.gov/permitting/water_rights/wr_technical-Plan is to identify and establish principles, practices, and resources/eflows.

standards to effectively conserve and efficiently use available In February 2020, the Texas Commission on Environmental ground and surface water supplies and meet historical Quality approved a revised Lower Colorado River Authority and projected average industrial water demand. Annual Water Management Plan. The Lower Colorado River implementation reports are submitted to the Texas Water Authority Water Management Plan determines how water is Development Board and the plan is updated every five allocated from the Highland Lakes (specifically Lakes Travis years. The station re-submitted a revised plan to the Texas and Buchanan) to meet the needs of water users, including Water Development Board in 2019. Managers and staff the South Texas Project, during water supply shortages. at the South Texas Project understand the water resources Photo courtesy of Arthur Miller C H APT 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 N G R EPORT 4 - 6

of the state are a critical natural resource requiring careful management and conservation to preserve water quality and availability. Accordingly, the station continues to support efforts focusing on the efficient use and conservation of water resources.

AIR QUALITY MANAGEMENT Air emission sources at the South Texas Project fall under the scope of air pollution regulations promulgated under Photo courtesy of Greg McMullin fossil fuel for backup and emergency equipment. Regulated emission sources at the South Texas Project include fossil-fueled emergency generators and fire pumps, fire-fighting training, and other minor maintenance equipment and activities.

The Federal Clean Air Act mandates a permitting program to Photo courtesy of Greg McMullin clearly define applicable air quality requirements for affected the Texas Clean Air Act and the Federal Clean Air Act and facilities such as the South Texas Project. This program is the numerous associated amendments. The purpose of commonly known as the Title V Federal Operating Permit these regulations is to protect air resources from pollution Program and is administered by the state. In 2019, South by controlling or abating air pollution and harmful emissions. Texas Project voided its Title V Federal Operating Permit in A report of air emissions is submitted annually to the Texas lieu of certifying its emissions. The station is now registered Commission on Environmental Quality. Although nuclear under Permit By Rule Registration No. 154767. Certified generation of electricity is a form of zero-emission clean emissions controls, like Title V, are federally enforceable energy, the South Texas Project uses small amounts of and must follow the guidelines of the Federal Clean Air Act.

Figure 4-1 4-7 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

This Permit By Rule Registration grants authority to operate The South Texas Project is classified as a small quantity identified emission sources at the station in accordance generator of industrial solid wastes. Texas Commission with applicable permit and regulatory requirements. on Environmental Quality regulations require industrial solid wastes generated at the South Texas Project to In 2021, the South Texas Project had no reportable air be identified to the Commission. These are listed in the emissions events and no violations.

Texas Commission on Environmental Quality Notice of Registration for the South Texas Project. The registration is revised whenever there is a change in waste management practices change at the site. Hazardous waste and Class I non-hazardous waste handling and disposal activities are summarized and documented in a waste summary report for the South Texas Project that is submitted annually to the Texas Commission on Environmental Quality. The South Texas Project five-year Source Reduction and Waste Minimization plan for hazardous waste was last updated and the associated executive summary was submitted to the Texas Commission on Environmental Quality in 2019.

Photo courtesy of Rudy Perez Unlike conventional electrical generating stations, nuclear power plants do not burn fossil fuel to produce electricity.

Therefore, the South Texas Project produces virtually no greenhouse gases or other air pollutants that are the typical by-products of industrial power production processes.

The use of emissions-free nuclear power is a significant Photo courtesy of Greg McMullin contributor to the preservation of our communitys clean Hazardous waste accumulation at the South Texas Project in air resources.

2021 was limited to a maximum holding period of 180 days.

NON-RADIOACTIVE WASTE MANAGEMENT The Resource Conservation and Recovery Act and Texas Solid waste management procedures for hazardous and Solid Waste Disposal Act also requires the use of proper non-hazardous wastes generated at the South Texas Project storage and shipping containers, labels, manifests, reports, ensure that wastes are properly dispositioned in accordance personnel training, a spill control plan, and an accident with applicable federal, state, and local environmental and contingency plan. South Texas Project personnel routinely health regulations. By regulatory definition, solid waste inspect areas throughout the site to ensure wastes are not includes solid, semi-solid, liquid, and gaseous waste stored or accumulated inappropriately.

material. The Texas Commission on Environmental Quality, South Texas Project policies and regulations encourage the which administers the Texas Solid Waste Disposal Act recycling, recovery, or reuse of waste, when possible, to and the federal Resource Conservation and Recovery Act reduce the amount of waste generated or disposed of in program, is the primary agency regulating non-radioactive landfills. Approximately 52 percent of the industrial Non-wastes generated at the South Texas Project. The Texas radioactive waste generated in 2021 at the South Texas Commission on Environmental Quality regulates the Project was recycled or processed for reuse (Reference collection, handling, storage, and disposal of solid wastes, Figure 4-1). Used oil, diesel fuels, electro-hydraulic fluid, including hazardous wastes. The transportation of waste and used oil filters were sent to a recycling vendor for materials is regulated by the United States Department reprocessing. Empty polyethylene drums are returned, of Transportation.

when possible, to the original manufacturer for reuse.

C H APT 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 N G R EPORT 4 - 8

Figure 4-2 Figure 4-3 In addition, the station supports recycling programs for amount of hazardous waste shipped each year generally cardboard, paper, aluminum, printer cartridges and plastic. reflect differences in operation and maintenance activities.

Approximately 225 tons of scrap metal were removed from Successful waste minimization and source reduction efforts the station for recycle in 2021. The South Texas Project by employees have allowed the South Texas Project to continues to explore new areas where recycling may be remain classified as a small-quantity waste generator since expanded or initiated. 2004. (Reference Figures 4-2 and 4-3).

Non-radioactive solid waste that cannot be shipped for CHEMICAL CONTROL AND MANAGEMENT recycling is shipped for disposal. The stations Integrated Spill Contingency Plan for the South Texas Project, last updated and re-certified in 2019, Municipal type trash is transported to an offsite landfill.

consolidates multiple federal and state requirements into Hazardous waste accounts for only a small portion of the one plan. The plan is implemented through standard site waste generated at the South Texas Project. Minimization operating procedures and guidelines. The South Texas and reduction of hazardous waste generation where Project uses standard operating procedures, policies, and feasible remains an important goal. Changes in the programs to minimize the generation of waste materials, 4-9 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

control chemical use, and prevent spills. The South Texas spillage. The South Texas Project emphasizes awareness Project also evaluates chemicals and products prior to training for spill prevention and maintains readiness to their approval for use at the station. Site procedures that respond should a spill occur. Spill response team members implement the stations Integrated Spill Contingency Plan receive annual refresher training in hazardous material and the stations Chemical Control Program address the incident response. The South Texas Project did not have evaluation, storage, use, labeling, spill control, and disposal any reportable liquid spills in 2021.

requirements of chemicals. These guidelines also assist in reducing waste generation, ensuring proper packaging for disposal, and mitigating the consequences of inadvertent 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 Regulatory Commission is was issued in March of 1989 to protect non-radiological provided with a copy of any environmental monitoring parameters during operation of the such reports at the time they nuclear plants. This report reviews Environmental Protection are submitted to the cognizant Plan non-compliances, if any, identified in 2021 and the agency. If a non-routine associated corrective actions taken to prevent recurrence. event occurs and a report Potential non-conformities are promptly addressed to is not required by another maintain operations in compliance with plan requirements. agency, then a 30-day report to the United States Nuclear Plant personnel use a condition reporting process to Regulatory Commission is document these conditions and track corrective actions to required by the Environmental completion. Internal assessments, reviews and inspections Protection Plan. No such are also used to ensure compliance.

30-day or other non-routine Events that require notifications to federal, state, or local event report was required agencies are reported in accordance with the applicable in 2021.

Photo courtesy of Christie Dement reporting requirements. The United States Nuclear 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:

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

adverse environmental impact previously evaluated in the * 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 2021.

C H APT 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 N G 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 A sampling program was developed to monitor the Tritium is designed to evaluate the radiological impact of the in the immediate area around the plant for long term South Texas Project on the environment by collecting trending. Wells are sampled either semi-annually, annually, and analyzing samples for low levels of radioactivity. or once every five years, depending on location and the Measurements of samples from the different pathways amount of Tritium present. The Tritium concentration indicate that there continues to be no adverse effect remained below the United States Environmental Protection offsite from the operation of the South Texas Project. Agency drinking water limits in 2021 and within the design basis of the South Texas Project.

Only Tritium and naturally occurring radioactive material were identified in the offsite environmental samples in 2021. Analyses of the data collected from the implementation Samples of fish and meat collected and analyzed showed of the Radiological Environmental Monitoring Program no South Texas Project related nuclides were present. indicates that the operation of the South Texas Project Water samples from the onsite drinking water supply from has no adverse radiological impact.

the deep aquifer and from offsite sampling stations on the Colorado River show only natural background radioactivity.

The station also monitors for radioactivity in onsite sediment from the Main Cooling Reservoir and ditches. Measurements of direct radiation onsite and offsite indicated no federal dose limits were exceeded.

Tritium is a radioactive isotope of hydrogen that is produced in the reactor and cannot be removed from effluents released to the Main Cooling Reservoir because it is part of the water molecule.

Due to the design of the Main Cooling Reservoir, the presence of Tritium in various sloughs and ditches onsite and the shallow aquifer is expected. Tritium has been Photo courtesy of Christie Dement detected in these types of samples and the concentrations remain below the United States Environmental Protection Agency drinking water limits.

Photo courtesy of Cheryl Bentley Photo courtesy of Rudy Perez 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 historical data and against the Control Stations. Indicator pre-operational Radiological Environmental Monitoring Stations are compared with characteristics identified during Program in July 1985. That program terminated on the pre-operational program to monitor for radiological March 7, 1988, when the operational program was effects from plant operation.

implemented. The data from the pre-operational Two sample identification methods are used in the program.

monitoring program form the baseline against which Figures 6-1 and 6-2 are maps that identify permanent operational changes are measured.

sample stations. Descriptions of sample stations shown Analyses of the environmental pathways require that on Figures 6-1 and 6-2 are found in Table 2. Table 2 also samples be taken from water, air, and land environments.

These samples are obtained to evaluate potential radiation exposure to people. Sample types are based on established pathways and experience gained at other nuclear facilities.

Sample locations were determined after considering site meteorology, site hydrology, local demography, and land use. Sampling locations are further evaluated and modified according to field and analysis experience. Table 1 at the end of this section lists the required sampling locations and frequency of collection. Additional discretionary samples were also collected.

Sampling locations consist of Indicator Stations and Control Stations. Indicator Stations are locations on or off Photo courtesy of Greg McMullin the site that may be influenced by plant discharges during includes supplemental sampling locations and media plant operation. Control Stations are located beyond the types that may be used for additional information. Figure measurable influence of the South Texas Project. Although 6-3 illustrates zones that may be used to complement most samples analyzed are accompanied by a control permanent, numbered sample stations.

sample, it should be noted that this practice is not always possible or meaningful with all sample types. Fluctuations Environmental samples from areas surrounding the South in the concentration of radionuclides and direct radiation Texas Project continue to indicate no radiological effects exposure at Indicator Stations are evaluated in relation to from plant operation. Measured values from offsite indicator sample stations continue to trend with the Control Stations.

Measurements from onsite indicator samples continued to fluctuate within normal historical ranges.

Photo courtesy of Christie Dement 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 -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 D E 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 N G 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 ENVIRONM 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 2021 (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 Photo courtesy of Rudy Perez gamma analyses revealed no radioactivity from the South Texas Project.

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 ING 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 The values plotted are the averages for all the stations with thermoluminescent dosimeters (TLDs) located at according to type. The average of the Control Stations is 40 locations around the site. The natural direct gamma higher than the other stations because Station #23 is exposure varies according to location because of differences in an area that has slightly higher natural background in the natural radioactive materials in the soil, soil moisture radiation. The trends of Figure 6-5 show that South Texas content, and other factors. Figure 6-5 compares the Project is not contributing to the direct radiation in the amount of direct gamma exposure measured at the plant offsite environment.

since the first quarter of 2001 from three different types of stations. The South Texas Project started using a vendor for offsite processing of the thermoluminescent dosimeters for environmental measurement of direct radiation during the third and fourth quarter of 2014. The Control Stations, Stations #23 and #37, are greater than 10 miles from the site in the minimal wind direction. The prevailing wind direction was into the northwest sector. The Sensitive Indicator Stations are one-mile NW, NNW, and N from the plants on FM 521 at Stations #15, #16 and #1 respectively.

The Indicator Stations are the remainder of the required Photo courtesy of Greg McMullin monitoring stations.

Figure 6-5 6-7 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

SEDIMENT SAMPLES Figure 6-6 Figure 6-7 The cobalt-60 inventory in the reservoir has decreased since and #216. In 2021, cobalt-60 was identified in zero out of 1992 because of radioactive decay and installed equipment seven Main Cooling Reservoir sediment samples taken, to reduce radioactive effluents. Although the total activity of all results were less than the reporting levels. Figure 6-7 cobalt-60 has decreased over time, an inventory of cobalt-60 demonstrates the calculated decline in the total amount is still in the reservoir as seen occasionally at Stations #215 of cobalt-60 in the reservoir. Bottom sediment samples 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 ING R EPORT 6 - 8

are taken from the Main Cooling Reservoir each year. A not identified in any other sediment sample in 2021.

study was performed in 2010 to locate the distribution and Cesium-137 was measured in four out of seven bottom concentrations of cobalt-60 and cesium-137 in the Main sediment samples from Stations #215 and #216 in the Main Cooling Reservoir. Although no cobalt-60 was detected Cooling Reservoir in 2021. The highest measurement was from 2007 through 2010 at Stations #215 and #216, the 28 pCi/kg at Station #216. The highest measurement at concentration of cobalt-60 is not uniformly distributed in the Station #215 was 20.6 pCi/ kg. Cesium-137 is often found in reservoir sediment and some cobalt-60 remains. Figure 6-6 environmental media including soil and sediment as residual and Figure 6-7 show the results from the plant-produced radioactive material resulting from aboveground nuclear cobalt-60 from the Main Cooling Reservoir. Cobalt-60 was Figure 6-8 Photo courtesy of Greg McMullin 6-9 ST P ANNUAL ENVIR ONM E N TAL OP E RAT I N G RE P ORT

weapons testing conducted in the 1950s and 1960s. Soil #216 in 2021 were slightly lower than previously detected and sediment samples taken in 1986 and 1987 prior to due to sampling non-homogeneous media. Results operation of the South Texas Project contained cesium-137 remained considerably less than reportable levels. The from weapons testing. The average pre-operational measured values at Station #215 and #216 are consistent cesium-137 concentration was 118 pCi/kg in soil and with pre-operational concentrations reduced by 30 years of sediment samples, and the highest sample concentration radioactive decay.

was 383 pCi/kg. Cesium-137 activities measured at Station Figure 6-9 WAT E R B O R N E PAT H WAY Tritium has been detected in the shallow aquifer on the the remainder is released into the Main Cooling Reservoir.

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

Project construction.

The concentration of Tritium in the Main Cooling Reservoir Tritium is a radioactive isotope of hydrogen and is produced was relatively stable in 2021. The amount of Tritium in the reactors during plant operation. Wastewater is treated measured in the Main Cooling Reservoir was consistent with to remove impurities before release, but Tritium cannot be the amount usually released to the reservoir. The amount removed because it is chemically part of the water molecule. of rainfall and reservoir makeup from the Colorado River Some of the Tritium is released into the atmosphere and influences the concentration of Tritium in the Main Cooling 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 -1 0

Figure 6-10 Reservoir and the shallow aquifer surrounding it. Tritium the water is diluted as it migrates through the reservoir enters the sloughs and ditches of the site as runoff from the relief well system. In 2021, ten out of twelve surface water relief wells that surround the reservoir. sample locations tested positive for Tritium. All test results were below the United States Environmental Protection In 2021, Tritium levels remained consistent with historical Agency drinking water limit of 20,000 pCi/kg. Rainwater values in the relief wells as shown in Figure 6-9. Sampling was collected and analyzed during 2021 to determine if of Main Cooling Reservoir relief well #701 has been the Tritium from the reservoir precipitated in the local area.

discontinued due to no water flow at that location. Another Tritium was not measured in any of the rainwater samples existing Main Cooling Reservoir relief well #707, is now used offsite.

as a representative substitute for sampling the relief well water from the Main Cooling Reservoir. Station #707 is just Tritium was identified in the shallow (i.e., ten to thirty feet west of the discontinued relief well #701 on the south side deep) aquifer test wells at Station #235 approximately of the Main Cooling Reservoir. Due to different flow rates seventy-five yards south of the reservoir embankment base of water through the relief wells, the base concentration during 1999. Starting in 2000, samples were collected is slightly higher at relief well #707 compared to #701. from the shallow aquifer well at Station #251 south of the The highest 2021 sample from relief well #707 indicated Main Cooling Reservoir. The Tritium results from these two approximately 6,394 pCi/kg, which is less than required shallow aquifer wells are shown in Figure 6-11. In 2021, the reporting levels. concentration of Tritium at Station #235 was consistent with values over the past ten years.

The Tritium concentrations in eight surface water sample locations from 2001 through 2021 are shown in Figure 6-10. Shallow aquifer Tritium concentrations have remained near The specific sample point locations can be found in Table the concentrations found in the relief wells. Wells at Stations

2. Tritium levels in the onsite sloughs and ditches vary with #258 and #259 on the west side of the site boundary have the concentration in the reservoir and the amount of rainfall been sampled since 2006. Wells at Stations #270 and #271 received. The average Tritium concentration in the relief well, were installed during the last quarter of 2008. The sample sloughs, and ditches are less than the reservoir because results are shown in Figure 6-12. The well at Station #271, 6-11 STP ANNUAL ENVIRONM E N TAL OP E RAT I N G RE P ORT

located adjacent to site property on a county road easement water for drinking. If the water with the highest Tritium directly west of the Main Cooling Reservoir, indicated its concentration that leaves the site was used for drinking, highest concentration for 2021 at 1,812 pCi/kg. In 2021, a the maximum dose to an individual would be less than one maximum value of 4,168 pCi/ kg was identified for onsite test millirem in a year. This dose is insignificant compared to the wells. Tritium levels continued to remain below the United approximately 620 millirem the public receives a year from States Environmental Protection Agency drinking water limit natural radioactivity in the environment and the radiation (20,000 pCi/kg). received from medical procedures.3 Tritium has not been detected in the deep aquifer that is Other samples are collected and analyzed in addition to the source of drinking water for the local communities and those required by our licensing documents or internal homes. These measurements follow the hydrological model procedures. These samples are collected to give additional described in the original license basis and the updated site assurance that the public and the environment are protected conceptual model discussed earlier in this section. from any adverse effects from the plant. These samples include pasture grass, sediment samples, rainwater, shallow A windmill-powered well, Station #267, was below detection aquifer well, water from various ditches and sloughs onsite, values in 2021. This onsite ground water sample station is direct radiation, and air samples near communities or other the most distant location from the Main Cooling Reservoir areas of interest. The results of these analyses indicate that that Tritium has been detected. This well is not used for plant operation has no health impact offsite and is well within human consumption.

state and federal regulations and guidelines.

The drinking water onsite is pumped from deep aquifer wells and is collected monthly and composited quarterly to verify 3 NCRP (2006). National Council on Radiation Protection and Tritium is not present. The South Texas Project does not use Measurements, Ionizing Radiation Exposure of the Population of water from the reservoir, shallow aquifers or other surface 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 NG 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 Institute (NEI) established a standard for monitoring and reporting radioactive isotopes in groundwater entitled NEI Groundwater Protection Initiative, NEI 07-07. The station implemented the recommendations of this industry standard and has broadened the groundwater 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 Photo courtesy of Greg McMullin high concentrations are sampled more frequently. Figure 6-13 contains the 2021 results for wells that were sampled other wells sampled in 2021 that had detectable Tritium are along with the historical highs measured prior to 2021 for influenced by groundwater originating in the Main Cooling each station since sampling began in 2006. Their locations Reservoir. Their concentrations remain in the range of are shown in Figure 6-14. groundwater Tritium concentrations associated with the Main Cooling Reservoir. All the 2021 measurements of Tritium Two wells sampled annually (Stations #807 and #808) in groundwater are a small fraction of the United States are adjacent to where a pipe was damaged and repaired Environmental Protection Agency drinking water limit (20,000 several years ago. The Tritium concentration at these pCi/kg).

two wells continued to decrease as expected in 2021.

Station #809 Tritium concentrations were related to the During 2012, steam traps for the auxiliary steam system previously referenced pipe and subsequent repair. All the that could potentially contain trace amounts of Tritium were 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 NG R EPORT 6-1 4

modified to re-direct the condensed steam or liquid water to for sampling the upper aquifer. The modifications were the Main Cooling Reservoir. Information regarding the steam completed in 2015 with continued improvements into 2016.

traps and subsequent response was documented in the In 2021, there was one occurrence where oily waste and stations condition reporting process.

three instances where condensed steam or water contacted This evaluation identified no new effluent release pathways the ground onsite. None of these occurrences resulted and no impact to the drinking water or the health and safety in impact to the public or the environment. No discharge of the public. occurred offsite or to groundwater that may be used as a source of drinking water. Where applicable, the water was By the end of 2014, the majority of the protected area wells quickly recovered, recaptured, and clean up completed had undergone a modification to enhance the protection with no impact to groundwater.

of the structural integrity of the water well casing used LAND USE CENSUS The Annual Land Use Census is performed to determine if any changes have occurred in the location of residents and the use of the land within five miles of the South Texas Project. 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 2021. The eleven sectors that have residents within five miles and the distance to the nearest residence in each sector are listed below.

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 commercial vegetable farms located approximately four to located within the five-mile zone.

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

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

also satisfy the collection

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

used to irrigate crops.

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

QUALITY ASSURANCE Quality assurance encompasses planned and systematic actions to ensure that an item or facility will perform satisfactorily. Reviews, surveillances, and audits have determined that the programs, procedures and personnel are performing at a satisfactory level.

Quality audits and independent technical reviews help to determine areas that need attention. These areas are addressed in accordance with the stations Condition Reporting Process.

The measurement capabilities of the Radiological Laboratory are demonstrated by participating in an interlaboratory Photo courtesy of Greg McMullin measurement assurance program as well as performing radioactive material in samples. Figure 6-15 summarizes duplicate and split sample analyses. Approximately 23 the results of the interlaboratory comparison programs.

percent of the analyses performed are quality control Duplicate sampling of the environment allows the South samples. These consist of interlaboratory measurement Texas Project to estimate the repeatability of the sample assurance program samples, duplicate samples, and split collection, preparation, and analysis process. Splitting samples. All analyses include National Institute of Standards samples allows estimation of the precision and bias trends and Technology samples, blanks, intercomparison testing, of the method of analysis without the added variables duplicates and splits out of a total of 1183 samples introduced by sampling. Generally, two samples split from analyzed for 2021.

the same original sample material should agree better than The interlaboratory measurement assurance program two separate samples collected in the same area and time.

provides samples that are similar in matrix and size to those The 2021 variances for duplicates and splits are shown measured by the Radiological Environmental Monitoring in Figure 6-16.

Program. This program assures that equipment calibrations and sample preparation methods accurately measure Photo courtesy of Zachary Phillips 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 6-1 6

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

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 2021 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.

Photo courtesy of Greg McMullin During 2021 samples not collected or unacceptable

• One broadleaf vegetation sample was not collected for analysis:

in March due to weather conditions, since this sample

• One out of 265 Offsite Dose Calculation Manual (ODCM) is outside the growing season it was not required by required air sample was not collected due to loss of power the ODCM.

from Station #1.

• One ODCM required thermoluminescent dosimeter (TLD)

• Fifteen air samples not required by the ODCM were not was not collected during the 4th quarter of 2021 because continuously collected for the full-time interval because of it was missing. An alternate TLD was in the same sector power or equipment failures.

during that period.

Photo courtesy of Zachary Bennett 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 6-1 8

6-19 STP ANNUAL ENVI RONM 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 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 Photo courtesy of Christie Dement 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 6-2 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. )

MCR-STP Main Cooling Reservoir STP- South Texas Project Photo courtesy of Rudy Perez Photo courtesy of Will Sharp 6-21 STP ANNUAL ENVIRON M 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. )

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 6-2 2

6-23 ST P ANNUAL ENVI RONM 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 LO C AT I O N D E S C R I P T I O N S Photo courtesy of Christie Dement 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 -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 Photo courtesy of Lee Carson 6-25 STP ANNUAL ENVIRON M 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 NG 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

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 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- 2 8

6-29 STP ANNUAL ENVIRON 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. according to availability, but exceeded the minimum number The table has been formatted to resemble a United required by Table 1, as well as other meat samples. Also, States Nuclear Regulatory Commission industry standard. numerous air station samples were collected from weekly Modifications have been made for the sole purpose of air sample stations, in addition to the minimum number of reading ease. Only positive values are given in this table. samples required by Table 1 to strengthen the Radiological Environmental Monitoring Program.

Media type is printed at the top left of each table, and the units of measurement are printed at the top right. The first column The minimum required Radiological Environmental Monitoring lists the type of radioactivity or specific radionuclide for which Program is presented in Table 1. The table is organized by each sample was analyzed. The second column gives the exposure pathway. Specific requirements such as location, total number of analyses performed and the total number of sampling method, collection frequency, and analyses are non-routine analyses for each indicated nuclide. A non-routine given for each pathway.

measurement is a sample whose measured activity is greater than the reporting levels for Radioactivity Concentrations in Environmental Samples. The LOWER LIMIT OF DETECTION column lists the normal measurement sensitivities achieved.

The sensitivities were better than required by the United States Nuclear Regulatory Commission.

A set of statistical parameters is listed for each radionuclide in the remaining columns. The parameters contain information from the indicator locations, the location having the highest annual mean, and information from the Control Stations. Some sample types do not have Control Stations.

When this is the case, no samples is listed in the control location column.

For each of these groups of data, the following is calculated: Photo courtesy of Greg McMullin

• The mean positive values

• The number of positive measurements / the total number of analyses

• The lowest and highest values for the analysis The data placed in Table 3 are from the samples required by the sites Offsite Dose Calculation Manual as described in Table 1. Additional thermoluminescent dosimeters were utilized each quarter for quality control purposes. The minimum samples required by Table 1 were supplemented in 2021 by numerous direct radiation measurements, additional surface water samples, ground water samples, Photo courtesy of Greg McMullin additional pasture grass, additional rainwater samples, additional relief well water samples, and additional sediment samples. Fish and crustacean samples vary in number Photo courtesy of Greg McMullin 6-29 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 Rudy Perez 6-31 ST P ANNUAL ENVIR ONM 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 NG R EPORT 6 -3 2 6-33 STP ANNUAL ENVIR ONM E N TAL OP E RAT I N G RE P ORT Photo courtesy of Gary Parkey 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

6-35 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 NG R EPORT 6-3 6 6-37 ST P ANNUAL ENVIRON M E N TAL OP E RAT I N G RE P ORT Photo courtesy of Rob Nies 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 8

6-39 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 NG R EPORT 6-4 0

Photo courtesy of Christie Dement Photo courtesy of Gary Parkey