Text

Submittal of 2016 South Texas Project Electric Generating Station Annual Environmental Operating Report
	ML17125A253
Person / Time
Site:	South Texas
Issue date:	04/19/2017
From:	Stone C; South Texas
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
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	NOC-AE-17003467
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Nuclear Operating Company South Texas Project Electric Generating Station P.O Box 28.9 Wadsworth. kms77-183 April 19, 2017 NOC-AE-17003467 File No.: G25 10 CFR 50.36b Attention: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 2016 South Texas Project Electric Generating Station Annual Environmental Operating Report Pu rsuant to South Texas Project Unit 1 Operating License NPF-76 and Unit 2 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 2016 Annual Environmental Operating Report.

There are no commitments included in this report.

If there are any questions, please contact Marilyn Kistler at (361) 972-8385.

Clayton B. Stone Manager, Health Physics MK

Attachment:

2016 South Texas Project Electric Generating Station Annual Environmental Operating Report STI: 34482055

NOC-AE-17003467 Page 2 of 2 cc:

(paper copy) (electronic copy)

Regiona l Administrator, Region IV Morgan, Lewis & Beckius LLP U.S. Nuclear Regulatory Commission Steve Frantz, Esquire 1600 East Lamar Boulevard Paul Bessette Arlington, TX 76011-4511 U.S. Nuclear Regulatory Comm ission Lisa M. Regner Lisa M. Regner Senior Project Manager U.S. Nuclear Regulatory Commission NRG South Texas LP One White Flint North (08H04) Mark Walker 11555 Rockville Pike Jim von Suski!

Rockville, MD 20852 Skip Zahn NRC Resident Inspector CPS Energy U. S. Nuclear Regulatory Commission Kevin Pollo P. 0. Box 289, Mail Code: MN116 Cris Eugster Wadsworth, TX 77 483 L. D. Blaylock Matagorda County Judge City of Austin Nate McDonald Elaina Ball 1700 7th Street Rm 301 John Wester Bay City, Texas 77414 Texas Dept. of State Health Services Commissioner Pet. 1 Helen Watkins Gary Graham Robert Free 2604 Nichols Road Bay City, Texas 77414 Commissioner Pet. 2 Kent Pollard Box 571 Matagorda , Texas 77457 Commissioner Pet. 3 James Gibson 25000 Hwy 35 South.

Palacios, Texas 77465 Commissioner Pet. 4 Charles Frick Box 99 El Maton , Texas 77440

The 2016 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 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 station's Offsite Dose Calculation Manual.

Graphics and artwork performed by Barbara Carnley Cover photo by: Kenneth Hilscher Maps provided by Janice Hopes Photography performed by: Cheryl Bentley, Brandon Cox, Gene Fisseler, Kenneth Hilscher, Lesley Hoffman, Jodie Jankauskas, Frank Jacobus, Raihan Khondker, Connie Milliff, Gary Parkey, Aubrey Passafuma, Rodolfo Perez, Robyn Savage, Debbie Schultz, Tammy Stevens, and Cheryl Yeamans SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Completed in accordance with Technical Specifications for United States Nuclear Regulatory Commission License Nos.

NPF-76 and NPF-80 April 2017 Authored by: £e..

L'?ura Stoicescu S-i--01°£:.e,s c'. u.

Staff Health Physicist Radiation Protection and avis, J.D.

Environmental Supervisor Regulatory Affairs Technical Review:

Ken K. Kawabata, CHP Consulting Health Physicist Radiation Protection Approved by: ~

Clayton B. Stone Manager Radiation Protection 2016 Annual Environmental Operating Report SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Table of Contents Executive Summary .................................................................................................. 1-2 Site and Area Description...................................................... ... ................................. 2-2 Nonradiological Environmental Introduction and Summary..................................... 3-2 Nonradiological Environmental Operating Report............ ........................................ 4-2 Environmental Conditions........ .................. ... ................................................. 4-2 Aquatic and Ecological Monitoring...... ..................................... ... ........ 4-2 Water Quality Management......................................................... ... .. .. 4-3 Air Quality Management ..................................................................... 4-7 Nonradioactive Waste Management.............. ..... ................................ 4-8 Chemical Control and Management .. .................................................. 4-11 Environmental Protection Plan Status ............................................................ 4-11 Radiological Environmental Introduction and Summary........................................... 5-2 Radiological Environmental Operating Report.......................................................... 6-2 Program Description................................................................. ...... ................ 6-2 Analysis of Results and Trends............................................................. 6-6 NEI Groundwater Protection Initiative ........................................................... 6-14 Land Use Census ......................................................... ................................... 6-16 Quality Assurance .......................................................................................... 6-17 Program Deviations ........................................................................................ 6-17 2016 Radiological Environmental Monitoring Program Analysis Summary ... 6-27 List of Figures Figure 2-1: Plant Water Systems..................................... .. .......................... 2-4 Figure 4-1: 2016 Nonradioactive Waste Management............................... 4-9 Figure 4-2: 2016 Nonradioactive Waste Generation ... ............................... 4-10 Figure 4-3: Hazardous Waste Shipped Historical Comparison .................... 4-10 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report 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......................................................................................... 6-9 Figure 6-7: Calculated Cumulative Curies of Cobalt-60 in the Main Cooling Reservoir............................................................................. 6-9 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 ............ 6-12 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 ..................... 6-15 Figure 6-15: 2016 Radiological Laboratory Quality Assurance Program Performance ................ ..................................................... 6-18 Figure 6-16: Duplicate & Split Agreement of Environmental Samples in 2016 ... 6-18 List of Tables Table 1: Radiological Environmental Monitoring Program ........................... 6-19 Table 2: Sample Media and Location Descriptions ....................................... 6-22 Table 3: 2016 Radiological Environmental Monitoring Program Analysis Summary ........................................................................... 6-28 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Photo courtesy of Raihan Khondker SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Executive Summary The South Texas Project Eletric Generating Station (South Texas Project) continues to operate with no adverse effect on the population or the environment. The exposure for people living in the area remains at less than one mil/irem 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 offsite and is well below state and federal regulations and guidelines. These programs are verified by the State of Texas through collection and analysis of samples and placement of the State's monitoring dosimeters and other onsite and offsite inspections.

This report describes the environmental monito ring programs, radiological and nonradiological, conducted at the South Texas Project during 2016. Included in this report are the Environmental Protection Plan Status, the results of the Radiological Environmental Monitoring Program, and the Land Use Census.

Non radiological environmental monitoring is performed each year as part of the station's overall Environmental Protection Plan which is intended to provide for protection of nonradiological environmental values during station operations . Nonradiological monitoring encompasses, as a minimum, water quality, air quality, waste generation and minimization, and local aquatic and terrestrial ecological cond itions. In 2016, non radiological monitoring by the station confirmed that the South Texas Project's efforts to respect and protect local environmental conditions were successful.

The South Texas Project continued to be rated by the Texas Commission on Environmental Quality as a high performer in the area of environmental compliance, continued to provide high-quality habitat areas for a variety of flora and fauna, and continued to have no indications of negative non radiological impacts to local environmental conditions.

The environment within a 15-mile radius of the South Texas Project is routinely monitored for radiation and radioactivity. Sampling locations are selected using weather, land use, and water use information. Two types of sampling locations are used . The first type, control stations, are located in areas that are beyond the measurable influence of the South Texas Project or any other nuclear facility. The sample results from these stations are used to explain radiation from sources other than the South Texas Project. Indicator stations are the second type of station. The samples from these stations measure any radiation contributed to the environment that could be caused by the South Texas Project. Indicator stations are located in areas close to the 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 " preoperational baseline."

Results from the indicator stations are compared to both current control sample results and the preoperational 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 Project's 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 1-2 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report 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 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 below.

The airborne pathway is sampled in areas around the South Texas Project by measuring the levels of radioactive iodine and particulate radioactivity on air filters . The 2016 airborne results were similar to preoperational levels detecting only naturally occurring radioactive material unrelated to the operation of the South Texas Project.

The waterborne pathway includes samples taken from surface water, groundwater, and drinking water. Also included in this pathway are sediment samples taken from the Main Cooling Reservoir and the Colorado River. Tritium was the on ly man-made nuclide consistently detected in water samples and was measured in the shallow aquifer, the Main Cooling Reservoir, ditches, and sloughs consistent with the South Texas Project Main Cooling Reservoir operating design . The levels of tritium found were near or lower t han the concentration of tritium in the Main Cooling Reservoir. Additional onsite wells have been sampled to map tritium migration. The average tritium level in the Main Cooling Reservoir remained stable throughout 2016. Tritium levels remain well below United States Nuclear Regulatory Commission reporting limits and within United States Environmental Protection Agency drinking water standards. Previously detected plant-related nuclides, such as cobalt-60 and cesium -137, were detected in the re servoir sediment at designated sample locations at very low concentrations. Additional samples had detectable cesium-137 which is normally present in the environment and is consistent with preoperational concentrations . Offsite sediment samples continue to show no radioactivity from the South Texas Project. In summary, the station produced no detectable waterborne effects offsite.

The ingestion pathway includes broad leaf vegetation, agricultural products, and food products .

Naturally occurring nuclides were detected at average environmental levels in the samples. The data indicated there were no man-made nuclides detected in these types of samples.

The direct exposure pathway measures environmental radiation doses using thermoluminescent dosimeters. These results are consistent with the readings from previous years and preoperational measurements indicating no effect from South Texas Project operations .

The South Texas Project continues to operate with no negative effect on the population or the environment. The dose 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 offsite and is well within state and federal regulations and guidelines. These programs are verified by United States Nuclear Regulatory Commission inspections, STP Nuclear Operating Company sponsored quality assurance audits, and the State of Texas through collection and analysis of samples and State radiation monitoring dosimeters.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 1-3

Photo courtesy of Frank Jacobus 1-4 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Site and Area Description 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 Publ ic 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 .

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 originally designed for a net electrical power output of 1,250 megawatts-electric (MWe) . Unit 1 received a low-power testing license on August 21, 1987, achieved initial criticality on March 8, 1988, and was declared commercially operational on August 25, 1988. Unit 2 received a low-power testing license on December 16, 1988, achieved initial criticality on March 12, 1989, and was declared commercially operational on June 19, 1989. The combined units currently produce enough electricity to serve more than two million homes and businesses throughout Texas . With nearly 1,200 baseline employees, the STP Nuclear Operating Company is the largest employer and source of revenue for Matagorda County.

The South Texas Project initiated activities in 2008 to pursue renewal of the operating licenses for Units 1 and 2 from the United States Nuclear Regulatory Commission. The license renewal application was submitted to the United States Nuclear Regulatory Commission in October of 2010 to request authorization to operate the South Texas Project, Units 1 and 2, for an additional 20 years beyond the period specified in the current licenses. Approval is anticipated in the fall of 2017. The Nuclear Regulatory Commission issued the final Supplemental Environmental Impact Statement for the license renewal in November of 2013 . The final Supplemental Environmental Impact Statement was prepared in compliance with the National Environmental Policy Act.

In September of 2007, a Combined Construction and Operating License Application (COLA) was filed with the United States Nuclear Regulatory Commission to build and operate two additional units, Units 3 and 4, at the South Texas Project. The Nuclear Regulatory Commission issued the Final Environmental Impact Statement for Units 3 and 4 in February of 2011. The Final Environmental Impact Statement was prepared in compliance with the National Environmental Policy Act. Issuance of the combined licenses for Units 3 and 4 was subsequently authorized by the United States Nuclear Regulatory Commission in February of 2016. Photo courtesy of Tammy Stevens 2-2 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report Nuclear energy continues to provide long-term cost stability and promote energy independence. It is our nation's largest source of carbon -free energy. As we work collectively to secure our state's long-term energy future, nuclear energy will continue to play an important role as a safe and reliable supply of clean baseload electricity.

HOW THE SOUTH TEXAS PROJECT WORKS Fossil-fueled and nuclear-powered steam generating plants operate on the same principle.

Fuel is used to produce heat to convert water into high-pressure steam. The steam is directed through a turbine to turn a generator. In a fossil fuel plant, either coal, lignite, oil or natural gas is burned in a boiler to produce the heat. In a nuclear plant, the reactor replaces the boiler and the "fissioning" or splitting of uranium atoms inside the reactor produces the heat.

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 reactor when control rods in the core are withdrawn. In pressurized water reactors, like those at the South Texas Proj ect, the fuel rods heat water circulating in sealed, stainless steel piping that passes through large heat exchangers called steam generators . The water in the reactor is under pressure to prevent boiling. This is why the South Texas Project's Units 1 and 2 reactors are called "pressurized water reactors."

This hot, pressurized water heats a separate supply of water in the steam generators to produce steam that is directed through the blades of a turbine generator to produce electricity. The steam is then fed to a condenser where a separate supply of cooling water from the Main Cooling Reservoir condenses it back into water that is then pumped back to the steam generator for reuse. A diagram of the plant water systems is shown in Figure 2-1. Photo courtesy of' Debbie Schultz SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 2-3

Site and Area Description PLANT WATER SYSTEMS SECONDARY LOOP PRESSURIZER COND ENSATE PUMP RESERVOIR (7000 ACRE LAKE)

CONTAINMENT PRIMARY LOOP WALL COOLING LOOP Figure 2-1 In addition to its safety systems, the South Texas Project has many built-in physical barriers designed to prevent the release of radioactive materials in the unlikely event of an accident.

The most visible ones are the 200-foot-tall, domed containment buildings with steel reinforced concrete walls four feet thick. Inside each of these massive structures, two more concrete walls provide another 11 feet of radiation shielding. The reactor vessel itself has steel walls six inches thick, and the fuel pellets inside it are sheathed in hardened metal tubes .

Nuclear energy has one of the lowest impacts on the environment. It is the most eco-efficient energy source because it produces the most electricity in relation to its minimal environmental impact. In 2015, the most recent year for which data is available, nuclear generation in the United States prevented 563.8 million metric tons of carbon dioxide, 0.67 million short tons of sulfur dioxide, and 0.4 million short tons of nitrogen oxide from entering the Earth's atmosphere. 1 Nuclear power plants also generated approximately 62 percent of all clean-air electricity in the United States in 2015. 2 Additional information on nuclear energy and the environment can be found on the website maintained by the Nuclear Energy Institute at http://www.nei.org.

1 Nuclear Energy Institute. Emissions Avoided by the U.S. Nuclear Industry. http ://www.nei.org/

KnowledgeCenter/ Nuclear-Statistics/ Environment-Emissions-Prevented/Emissions-Avoided-by-the-US-Nuclear-lndustry. April 2016.

2 Nuclear Energy Institute. Environment: Emissions Prevented . http ://www.ne i.org/Knowledge-Center/

NuclearStatistics/Environment -Em issions-Prevented . Viewed on February 13, 2017 .

2-4 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report THE PLANT SITE Sixty-five o~ 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 relief of the area is characterized by flat land, approximately 23 feet above sea level.

THE AREA Matagorda County's economy is based primarily on ranching, farming, oil and natural gas production and refinement, petrochemical production, electricity generation, and commercial fishing and fisheries. The area within 10 miles of the site is generally rural and characterized as farmland, which is primarily pastureland used for livestock ranching. Although the surrounding area is heavily cultivated, significant amounts of woodlands, thicket, brush, fields, marsh, and open water exist to support wildlife. The area lies in the southern region of the central flyway and is host to an abundance of migratory birds . The local estuary environments provide the necessary habitat for a variety of fish types to complete their life cycles. The area also affords opportunity for recreational hunting and fishing.

The South Texas Project is home to many species of animals. Inhabitants include American alligators, a variety of birds, and several hundred deer. In winter, literally hundreds of thousands of waterfowl, principally migratory geese as well as white pelicans, have found that the plant's 7,000-acre cooling reservoir provides a good resting place during their migrations.

The climate of the region is subtropical maritime, with continental influence. It is characterized by short, mild winters and long, hot and humid summers. Rainfall normally ranges from about two inches per month in February peaking to about four to five inches per month in May, June, September and October. The prevailing wind direction is from the south-southeast, shifting to north -northeast for short intervals during the winter months. Photo courtesy of Connie Milli.ff SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 2-5

Site and Area Description Photo courtesy of Gene Fisseler 2-6 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Nonradiological Environmental Introduction and Summary Nonradiological environmental conditions and performance at the South Texas Project during 2016 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 2016.

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

The station's commitment to sound environmental management in 2016 is illustrated by the following :

Continued classification as a high performer 3 by the Texas Commission on Environmental Quality based on the station's environmental compliance record in all areas considered, including water quality, waste management, and air quality compliance;

Completion of two onsite regulatory inspections by the Texas Commission on Environmental Quality with no violations identified; and,

Continued emphasis on waste minimization and source reduction allowing the station to maintain its classification as a small quantity generator of industrial waste . Photo courtesy of Robyn Savage 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 for station activities.

3 Per Compliance History Report for CN601658669, RN102395654, Rating Year 2016; as prepared by the Texas Commission on Environmental Quality on February 14, 2017.

3-2 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report Photo courtesy of Tammy Stevens SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 3-3

Photo courtesy of Cheryl Bentley 3-4 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Nonradiological Environmental Operating Report ENVIRONMENTAL CONDITIONS This section of the report describes the South Texas Project's non radiological environmental program performance and environmental conditions from January 1 through December 31, 2016. The STP Nuclear Operating Company closely monitors environmenta l 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 conducted one onsite air quality permit compliance inspection and one onsite potable water compliance inspection in 2016.

The Texas Commission on Environmental Quality rated the South Texas Project as a high performer in 2016 based on the station's 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 facility's compliance history. The state's classification of the South Texas Project as a high performer was based on the station's environmental performance over the last five year period.

The South Texas Project, along with other local industries and organizations, co-sponsored and participated in the annual Matagorda County Household Hazardous Waste Collection Day in the fall of 2016, and station employees also participated in other community area environmental projects such as the Matagorda County Beach Cleanup . During the period of this report, the station continued to promote "green" initiatives including encouraging carpooling among employees and the recycling of paper, plastics and aluminum by site employees. The station also continued to support various bird counts and surveys in 2016 sponsored by federal and state agencies and volunteer organizations such as the annual National Audubon Society Christma s Bird Count, the Great Texas Birding Classic, and the United States Fish and Wildlife Service's Colonial Waterbird Survey.

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 based on topography, soils, and vegetation. The bottomland lowland habitat is a swampy, marshy area that provides an important habitat for birds and other wildlife and occupies approximately 1, 700 acres of the site near the Colorado River. An upland spoil containment area, originally constructed in 1972 by the United States Army Corps of Engineers, is included in this area. In addition, a 110-acre wetland habitat area that attracts a variety of bird groups and other wildlife was established in 1996 on previously unused land located northeast of the power plants. In 2012, the Matagorda County chapter of Ducks Unlimited awarded the station the John Runnels Good Steward Award for maintenance of the wetland habitat area. The remaining area of the site offers diverse habitats for mammals and several types of birds. The South Texas Project regularly monitors the site's environs for changing conditions. Ecological conditions onsite in 2016 rema ined 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, 4-2 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report in which the South Texas Project is located, consistently ranks at or near the top of the National Audubon Society's 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 site's diverse natural and man-made habitats. Intensive bird nesting continues throughout the lowland habitat, particularly in a heron rookery around the perimeter of Kelly Lake and on the internal dikes of the Main Cooling Reservoir at the South Texas Project. The South Texas Project continues to provide vital habitat for more than an estimated 125 different 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 live. The site continues to attract extensive wildlife populations, offering a 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 areas, offer the key ingredients necessary to sustain the extensive wildlife population at the South Texas Project.

WATER QUALITY MANAGEMENT Water is an essential component in electricity production, and all 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 water supplies and maintaining the integrity of state and federal waters. Regulating agencies that administer these requirements include the United States Army Corps of Engineers, the United States Environmental Protection Agency, the Texas Commission on Environmental Quality, the Texas General Land Office, the Lower Colorado River Authority and the Coastal Plains Groundwater Conservation District. The Texas Commission on Environmental Quality conducted an onsite potable water compliance inspection in 2016. One area of concern was identified regarding a water well flow totalizer that was not indicating flow at the time of the inspection. The issue with the flow totalizer, self-identified by station personnel, was resolved promptly and no further action was required.

The South Texas Project uses both surface water and groundwater for station purposes.

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.

Consistent with the station's environmental principles encouraging efficient water usage and conservation, surface and groundwater usage is carefully managed to conserve this important resource . Water from the Main Cooling Reservoir and the Essential Cooling Pond is used as cooling water for plant activities. Water from the Colorado River replenishes the Main Cooling Reservoir via intermittent diversion periods. Surface water diverted to the Main Cooling Reservoir SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 4-3

Nonradiological Environmental Operating Report from the Colorado River accounted for 92 percent of the water used at the South Texas Project in 2016. Information regarding water use in Texas can be found on the website maintained by the Texas Water Development Board at http://www.twdb.state.tx .us/.

Most of the water used by the South Texas Project is needed to condense steam and provide cooling for plant generating systems. The majority of this water is drawn from and returned to the station's Main Cooling Reservoir. The Main Cooling Reservoir is a 7,000-acre, above grade, off-channel reservoir capable of impounding 202,600 acre-feet of water at its maximum level.

Water is diverted intermittently from the adjacent Colorado River to replenish the Main Cooling Reservoir. In addition, the Essential Cooling Pond, a 47-acre, below grade, off-channel reservoir that supplies water to cool crucial plant components, is capable of impounding 388 acre-feet of water. Various water rights permits, contractual agreements, and compliance documents authorize the South Texas Project to maintain these reservoirs, impound water diverted from the Colorado River, and to circulate, divert, and use water from the reservoirs for industrial purposes to operate the plant. These authorizations also limit the amount and rate of diversion from the Colorado River to protect downstream environmental flow requirements for bays and estuaries. The South Texas Project diverted 15,420 acre-feet in 2016 from the Colorado River for Main Cooling Reservoir fill operations while preserving adequate freshwater flow conditions for downstream bay and estuarine ecosystems. Approximately 1,294 acre-feet, of the water used by the station was withdrawn from onsite groundwater sources in 2016.

Existing federal and state water quality standards are implemented and enforced through the Texas Pollutant Discharge Elimination System (TPDES) permit program to restore and maintain the state's 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. A monthly monitoring report is submitted to the Texas Commission on Environmental Quality for wastewater discharges.

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 the Coastal Plains Groundwater Conservation District in accordance with groundwater district requirements.

Wastewater generated at the South Texas Project is processed and discharged to the onsite Main Cooling Reservoir to be re-used by the station as cooling water for plant systems. No water was discharged from the Main Cooling Reservoir in 2016.

No aquatic monitoring was required to be conducted at the site in 2016 by the United States Environmental Protection Agency or the Texas Commission on Environmental Quality.

Wastewater discharges met state and federal water quality standards during the year, while conserving and maximizing Photo courtesy of Lesley Hoffman efficient water usage at the South Texas Project.

4-4 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report In addition to the wastewater discharge permit program, the Federal Clean Wate r Act, as amended, requires permits for storm water discharges associated with industrial activity. The South Texas Project's Storm Water Pollution Prevention Plan ensures that potential pollution sources at the sit e are evaluated and that appropriate measures are selected and implemented to prevent or control the discharge of pollutants in storm water runoff. This plan is a document that is revised whenever there is a change in design, construction, operation, or maintenance that has a significant effect on the potential for the discharge of pollutants from the station . The station's Multi-Sector General Permit for storm water discharges was renewed in 2016.

Following a severe drought in 1996, the Texas Legislature recognized the need to address a wide range of state water resource management issues. In 1997, the Texas Senate drafted legislation known as Senate Bill 1 to address these issues and to develop a comprehensive state water policy. Towards this end, this legislation required that the Texas Water Development Board create a statewide water plan that emphasizes regional planning. Sixteen planning regions were created, each tasked to prepare a regional plan for the orderly development, management, and conservation of water resources . The South Texas Project was chosen to represent the electric generating utility interest for the water-planning region, Region K, encompassing the lower Colorado River Basin . A state water plan is prepared by the Texas Water Development Board based on the regional water plans that are developed every five years by the regional water planning groups. The fourth cycle of regional and state water planning concluded in 2015 and the fifth planning cycle commenced in 2016. 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 December of 2015, the water plan adopted by the Region K water planning group was submitted to the Texas Water Development Board for approval. This plan was incorporated into the state water plan which was published in 2016 for all water user groups in the state. 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 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 http ://www.twdb.state .tx .us/.

Senate Bill 1 also required groundwater conservation districts to develop groundwater management plans with estimates on the availability of groundwater in the district, details of how the district would manage groundwater, and management goals for the district.

The water planning and management provisions were further clarified in 2001 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. The station's groundwater wells' operating permits were last renewed in 2014 as required every three years. Station personnel continue to monitor onsite groundwater usage according to the requirements of the District's rules . Additional information regarding the Coastal Plains Groundwater Conservation District can be found on its website at http://

www.coastalplainsgcd.com/.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 4-5

Nonradio/ogical Environmental Operating Report In 2007, in further recognition of the importance of wate r conservation to meet future demands in the state, Senate Bill 3, enacted by the Texas Legislature, created a stakeholder-driven process fo r the development of environmental flows. Environmental flows are the amount of wate r necessary for a river, estuary, or other freshwater system to maintain its health and productivity. The law establ ished a process to develop environmental flow regime recommendations for each major river basin in Texas. The process tasked a team of stakeholders for each area of the state, working with a science team, to develop a set of recommendations to submit to the Texas Commission on Environmental Quality and to perform ongoing periodic reviews of the recommendations. The South Texas Project participates as a member of the stakeholder committee that includes 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 surface water diversion right is not impacted by this legis lation . Additional information regarding environmental flows can be found athttp ://www.tceq .texas .gov/ permitting/

water_supply/water_rights/eflows/.

In November 2015, the Texas Commission on Environmental Quality approved a revised Lower Colorado River Authority Water Management Plan . The Lower Colorado River Authority Water Management Plan determines how water is allocated from the Highland Lakes (specifically, Lakes Travis and Buchanan) to meet the needs of water users, including the South Texas Project, during water supply shortages. To assist with the development of a revised plan, the Lower Colorado River Authority assembled an advisory committee to represent the diverse interests that rely on the Highlands Lakes water supply. The advisory committee included representatives from cities, industry, lake area business and residents, the environment and agriculture. The South Texas Project represented industrial firm water customers on the advisory comm ittee. Additional information on the Lower Colorado River Authority Water Management Plan can be found at http ://

www.lcra.org.

In 1999, the South Texas Project implemented a station Water Conservation Plan in accordance with state water use regulations. The purpose of the station's Water Conservation Plan is to identify and establish principles, practices, and standards to effectively conserve and efficiently use available ground and surface water supplies and provide historical and projected average industrial water demand. Annual implementation reports are submitted to the Texas Water Development Board and the plan is required to be updated every five years .

The station reviewed, updated and re-submitted a revised plan to the Texas Water Development Board in 2014. The South Texas Project personnel understand that the water resources of the state are a critical natural resource requiring careful management and conservation to preserve water quality and availability. Accordingly, the station continues to explore and support efforts focusing on the efficient Photo courtesy of Robyn Savage use and conservation of water resources .

4-6 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report AIR QUALITY MANAGEMENT Air emission sources at the South Texas Project fall under the scope of air pollution regulations promulgated under the Texas Clean Air Act and the Federal Clean Air Act and the numerous associated amendments. The purpose of these regulations is to protect air resources from pollution by controlling or abating air pollution and harmful emissions . The South Texas Project uses small amounts of fossil fuel for backup and emergency equipment. Regulated emission sources at the South Texas Project include a fossil-fueled auxiliary boiler, fossil -fueled emergency generators and fire pumps, fire-fighting training, and other minor maintenance equipment and activities. The station submits a report of air emissions annually to the Texas Commission on Environmental Quality. In 2016, one emission event occurred and was reported to the Texas Commission on Environmental Quality. This event was associated with a halon release that occurred in August of 2016 as a result of a pressure test gauge assembly internal valve core manufacturing defect. Halon is used in limited applications at the station for fire protection purposes .

The South Texas Project has one fossil fuel-fired auxiliary steam boiler available to furnish steam for plant use when steam is not available from the nuclear steam supply system . In addition to the auxiliary steam boiler, a number of fossil-fueled emergency generators are located onsite . These generators are designed to provide power to various plant systems or buildings in the event of a loss of power from normal sources . This equipment is not normally needed for daily operations and the station does not use it to produce electricity for distribution. Routine maintenance runs are conducted to ensure availability if needed and for required equipment maintenance.

The Federal Clean Air Act mandates a permitting program to clearly define applicable air quality requirements for affected facilities such as the South Texas Project. This program is commonly known as the Title V Federal Operating Permit Program and is administered by the state . The station's Federal Operating Permit grants authority to operate identified emission sources at the station in accordance with applicable permit and regulatory requirements. The South Texas Project submitted an application to the Texas Commission on Environmental Quality for renewal of this permit in 2015 and the renewed permit was received in 2016. Under the terms and conditions of the permit, the station is also required to submit deviation reports, if identified, to the Texas Commission on Environmental Quality on a semi-annual basis. Three deviations occurred in 2016 in addition to the emission event discussed earlier in this section . Two of the deviations from permit conditions were associated with the operation and maintenance of two small emergency diesel generators and were included in the station's semi-annual deviation report to the Texas Commission on Environmental Quality in accordance with applicable permit requirements . A separate deviation was included for not identifying one of the deviations in the period in which it occurred.

An onsite inspection was conducted by the Texas Commission on Environmental Quality in 2016 for compliance with applicable requirements for air quality as identified in the station's Federal Operating Permit. No findings or violations were identified .

Unlike conventional electrical generating stations, nuclear power plants do not burn fossil fuel for the production of electricity. Therefore, the South Texas Project produces virtually no greenhouse gases or othe r air pollutants that are the typical by-products of industrial production processes. The use of emissions-free nuclear power is a significant contributor to the preservation of our community's clean air resources .

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 4-7

Nonradiological Environmental Operating Report NONRADIOACTIVE WASTE MANAGEMENT Solid waste management procedures for haza rdous and non-hazardous wastes generated at the South Texas Project ensure that wastes are properly dispositioned in accordance with applicable federal, state, and local environmental and health regulations . By regulatory definition, solid waste includes solid, semi-solid, liquid, and gaseous waste material. The Texas Commission on Environmental Quality, which administers the Texas Solid Waste Disposal Act and also the federal Resource Conservation and Recovery Act program, is the primary agency regulating nonradioactive wastes generated at the South Texas Project. The Texas Commission on Environmental Quality regulates the collection, handling, storage, and disposal of solid wastes, including hazardous wastes. The transportation of waste materials is regulated by the United States Department of Transportation.

The South Texas Project is classified as a small quantity generator of industrial solid wastes.

Texas Commission on Environmental Quality regulations require that industrial solid wastes generated at the South Texas Project be identified to the Commission. These are listed in the 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 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 station's five -year Source Reduction and Waste Minimization plan for hazardous waste was last updated and the associated executive summary submitted to the Texas Commission on Environmental Quality in 2014.

Hazardous waste accumulation at the South Texas Project in 2016 was limited to a maximum holding period of 180 days. The Resource Conservation and Recovery Act and Texas Solid Waste Disposal Act also requires the use of proper storage and shipping containers, labels, manifests, reports, personnel training, a spill control plan, and an accident contingency plan. South Texas Project personnel routinely inspect areas throughout the site to ensure wastes are not stored or accumulated inappropriately.

2016 Matagorda County Household Hazardous Waste Collection Day.

Photo courtesy of Brandon Cox 4-8 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report South Texas Project policies and regulations encourage the recycling, recovery, or reuse of waste when possible to reduce the amount of waste generated or disposed of in landfills.

Approximately 92 percent of the industrial nonradioactive waste generated in 2016 at the South Texas Project was 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.

Non-hazardous blast grit, spent batteries, and construction debris were also shipped for recycle in 2016. In addition, the station supports recycling programs for cardboard, paper, aluminum, printer cartridges and plastic. Approximately 123 tons of scrap metal were removed from the station for recycle in 2016. The South Texas Project continues to explore new areas where recycling may be expanded or initiated.

Nonradioactive solid waste that cannot be shipped for recycling is shipped for disposal. Municipal-type trash is transported to an offsite landfill. Of the waste generated at the South Texas Project, hazardous waste accounts for only a small portion. Minimization and reduction of hazardous waste generation where feasible remains an important goal. Changes in the amount of hazardous waste shipped each year generally reflect differences in operation and maintenance activities that result in the generation of hazardous waste . An increase in the amount of hazardous waste shipped in 2016 is attributable to a one-time generation of chemical waste generated from station maintenance improvement activities associated with Unit 2 chemical feed pumps. Successful waste minimization and source reduction efforts by employees have allowed the South Texas Project to remain classified as a small-quantity waste generator since 2004. (Reference Figures 4-2 and 4-3) 2016 Nonradioactive Waste Management South Texas Project Recyde 92" Landfill 6%

Biological Treatment Incineration & Fuel 0% Blending 2%

Figure 4-1 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 4-9

Nonradiological Environmental Operating Report 2016 Nonradioactive Waste Generation South Texas Project Non-Hazardous Waste 99.2%

...__ _ _ Universal Waste 0.1%

Hazardous Waste 0.1% Used Batteries 0.6%

Figure 4-2 Hazardous Waste Shipped Historical Comparison South Texas Project 4

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2016 Environmental Report CHEMICAL CONTROL AND MANAGEMENT The station's Integrated Spill Contingency Plan for the South Texas Project, last updated and recertified in 2014, consolidates multiple federal and state requirements into one plan . The plan is implemented through standard site operating procedures and guidelines. The South Texas Project uses standard operating procedures, policies, and programs to minimize the generation of waste materials, control chemical use, and prevent spills. The South Texas Project also evaluates chemicals and products prior to their approval for use at the station . Site procedures that implement the station's Integrated Spill Contingency Plan and the station's Chemical Control Program address the evaluation, storage, use, labeling, spill control, and disposal requirements of chemicals. These guidelines also assist in reducing waste generation, ensuring proper packaging for disposal and mitigating the consequences of inadvertent spillage.

The South Texas Project emphasizes awareness training for spill prevention and maintains spi ll response readiness to respond should a spill occur. Spill response team members receive annual refresher training in hazardous material incident response. No reportable, significant, or consequential liquid spills occurred in 2016.

ENVIRONMENTAL PROTECTION PLAN STATUS The South Texas Project's Environmental Protection Plan was issued in March of 1989 to protect non radiological environmental values during operation of the South Texas Project.

This report reviews Environmental Protection Plan non-compliances, if any, identified by the plant in 2016 and the associated corrective actions taken to prevent their recurrence.

Potential nonconformities are promptly addressed, as identified, to maintain operations in an environmentally acceptable manner. The station uses its Condition Reporting Process to document these conditions and track corrective actions to completion . Internal assessments, reviews and inspections are also used to document compliance .

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 adverse environmental impact previously evaluated in the Final Environmental Statement related to the Operation of South Texas Project, Units 1 and 2 (Docket Nos. 50-498 and 50-499),

environmental impact appraisals, or in any decisions of the Atomic Safety and Licensing Board; or, 2} A significant change in effluents or power level; or, 3} A matter not previously reviewed and evaluated in the documents specified in (1) above, that may have a significant adverse environmental impact.

No unreviewed environmental questions were identified in 2016.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 4-11

Nonradiological Environmental Operating Report Events that require notifications to federal, state or local agencies, other than the United States Nuclear Regulatory Commission, are reported in accordance with the applicable reporting requirements. The United States Nuclear Regulatory Commission is provided with a copy of any such reports at the time they are submitted to the cognizant agency. If a nonroutine event occurs and a report is not required by another agency, then a 30-day report to the United States Nuclear Regulatory Commission is required by the Environmental Protection Plan. No such 30-day or other non-routine event report was required in 2016.

Photo courtesy of Robyn Savage 4-12 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report Photo courtesy of Robyn Savage SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 4-13

Photo courtesy of Raihan Khondker 4-14 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Radiological Environmental Introduction and Summary 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 2016. Samples of fish and meat collected and analyzed showed no South Texas Project related nuclides were present. Water samples from the onsite drinking water supply from the deep aquifer and from offsite sampling stations on the Colorado River show only natural background radioactivity. The station also continues to monitor for radioactivity in onsite sediment of the Main Cooling Reservoir and ditches. Measurements of direct radiation onsite and offsite indicated no 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 a part of the Photo courtesy of Cheryl Bentley 5-2 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report water molecule . Due to the design of the Main Cool ing Reservoir, the presence of tritium in various sloughs and ditches onsite and the shallow aquifer is expected. Tritium has bee n detected in these types of samples and the concentrations remai n below the United States Environmental Protection Agency drinking water limits.

A sampling program was developed to monitor the tritium in the immediate area around the plant for long term trend ing. 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 2016 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 that the operation of the South Texas Project has no adverse offsite radiological impact.

Photo courtesy of Kenny Hilscher SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 5-3

Photo courtesy of Kenny Hilscher 5-4 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

Radiological Environmental Operating Report PROGRAM DESCRIPTION The South Texas Project initiated a comprehensive preoperational Radiological Environmental Monitoring Program in July 1985. That program terminated on March 7, 1988, when the operational program was implemented . The data from the preoperational monitoring program forms 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 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 the site that may be influenced by plant discharges during plant operation .

Control stations are located beyond the measurable influence of the South Texas Project.

Although most samples analyzed are accompanied by a control sample, it should be noted that this practice is not always possible or meaningful with all sample types. Fluctuations in the concentration of radionuclides and direct radiation exposure at indicator stations are evaluated in relation to historical data and against the control stations.

Indicator stations are compared with characteristics identified during the preoperational program to monitor for radiological effects from plant operation.

Two sample identification methods are used in the program. Figures 6-1 and 6-2 are maps that identify permanent sample stations.

Descriptions of sample stations shown on Figure 6-1 and 6-2 are found in Table 2. Table 2 also includes supplemental sampling locations and media types that may be used for additional information .

Figure 6-3 illustrates zones that may be used to complement permanent, numbered sample stations. Photo courtesy of Cheryl Yeamans 6-2 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM DESIGNATED SAMPLE LOCATION MAP Figure 6-1 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-3

Radiological Environmental Operating Report RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ONSITE SAMPLE LOCATION MAP 2

Figure 6-2 6-4 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ZONE LOCATION MAP The zone station is determined in the following manner:

The first character of the station number "Z" to identify it as a zone station.

The second character is the direction coordinate number 1-8.

The third character is the distance from the site number 1-6.

Figure 6-3 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-5

Radiological Environmental Operating Report ANALYSIS OF RESULTS AND TRENDS Environmental samples from areas surrounding the South Texas Project continue to indicate no radiological effects from plant operation . Measured values from offsite indicator sample stations continue to trend with the control stations. Measurements from onsite indicator samples continued to flu ctuate within normal historical ranges.

e ** I Airborne Pathway I ** e Average quarterly air particulate sample beta activity from three onsite indicator stations and a single control station have been compared historically from 2001 through 2016 (see Figure 6-4). The average of the onsite ind icators 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 analyses are performed on quarterly composites of the 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.

Historical Comparison of Average Quarterly Beta Activity from Indicator and Control Air Samples 2001- 2016

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I Direct Exposure Pathway Direct gamma radiation is mon itored in the environment by thermoluminescent dosimeters I ** e (TLDs) located at 40 sites. The natural direct gamma radiation varies according to location because of differences in the natural radioactive materials in the soil, soil moisture content, and other factors . Figure 6-5 compares the amount of direct gamma radiation measured at the plant since the fourth 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 rad iation 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 NW 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 stations. The values plotted are the averages for all of the stations according to type . The average of the Control Stations is higher than the other stations because station #23 is in an area that has a slightly higher natural background radiation. The trends of Figure 6-5 show that South Texas Project is not contributing to the direct radiation in the offsite environment.

Environmental Dosimeter Comparisons

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Radiological Environmental Operating Report

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The cobalt-60 inventory in the reservoir has decreased since 1992 because of radioactive decay and equipment installed to reduce radioactive effluents. Although the total activity of cobalt-60 has decreased over time, an inventory of cobalt-60 is still in the reservoir as seen occasionally at Stations #215 and #216 . In 2016, cobalt-60 was identified in seven out of seven sediment samples taken, but all results were less than the reporting levels. Figure 6-7 demonstrates the calculated decline in the total amount of cobalt-60 in the reservoir. Bottom sediment samples are taken from the Main Cooling Reservoir each year. A study was performed in 2010 to locate the distribution and concentrations of cobalt-60 and cesium-137 in the Main Cooling Reservoir.

Although no cobalt-60 was detected from 2007 through 2010 at Stations #215 and #216, the concentration of cobalt-60 is not uniformly distributed in the reservoir sediment and some cobalt-60 still remains . Figure 6-6 shows the positive results from the plant-produced cobalt-60.

Cesium-137 was measured in seven out of seven bottom sediment samples from Stations

215 and #216 in the Main Cooling Reservoir. The highest measurement was 99.4 pCi/kg at Station #216. The highest measurement at Station #215 was 79.8 pCi/kg. Cesium-137 is often found in environmental media including soil and sediment from residual radioactive material resulting from nuclear weapons testing . Soil and sediment samples taken in 1986 and 1987 prior to operation of the South Texas Project contained cesium -137 from weapons testing. The preoperational average cesium-137 concentration was 118 pCi/kg when it was detected in soil and sediment samples but the highest sample measured was 383 pCi/kg. Cesium-137 activities measured at Station #216 in 2016 were slightly higher than previously detected due to sampling nonhomogeneous media. In addition, results remained considerably less than reportable levels.

The measured values at Station #215 and #216 are consistent with preoperational concentrations reduced by 30 years of radioactive decay.

* * *

Waterborne Pathway * * * *

Tritium has been detected in the shallow aquifer since 1997 on the south side of the Main Cooling Reservoir. Models used when licensing the site predicted tritium in the shallow aquifer. These models were validated with additional studies for the proposed Units 3 and 4. A site conceptual model, developed in 2008 and updated in 2014, validated the original predictions of the site hydrology study.

Tritium is a radioactive isotope of hydrogen and is produced during plant operation. Tritium produced in the reactors is a part of the water molecule. Wastewater is treated to remove impurities before release, but tritium cannot be removed because it is chemically part of the water molecule. Some of the tritium is released into the atmosphere, and the remainder is released into the Main Cooling Reservoir. The tritium escapes from the Main Cooling Reservoir by evaporation, movement into the shallow aquifer, and by percolation from the relief wells which are a part of the reservoir embankment's stabilization system. Figure 6-8 shows the amount of tritium released to the Main Cooling Reservoir each year and the amount present during the last quarter of each year.

The concentration of tritium in the Main Cooling Reservoir was relatively stable in 2016. The amount of tritium measured in the Main Cooling Reservoir was consistent with the amount usually released to the Main Cooling Reservoir. The amount of rainfall and reservoir makeup from 6-8 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report Historical Comparison of Cobalt-60 in the Main Cooling Reservoir Sediment 2001- 2016 350

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1. Radioactive decay is the only mechanism for removal from the Main Cooling Reservoir.

2. The initial time for calcu lating the remaining radioactivity is July 1 of t he year released .

Figure 6-7 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-9

Radiological Environmental Operating Report Historical Comparison of Tritium Added to and Remaining in the Main Cooling Reservoir 2001- 2016 3500 3000 2500 E

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2016 Environmental Report 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 2016, tritium levels remained consistent with historical values in the relief wells as shown in Figure 6-9. Sampling of the Main Cooling Reservoir relief well #701 has been discontinued due to no water flow at that location . A new 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 just west of the discontinued relief well #701 on the south side of the Main Cooling Reservoir. Due to different flow rates of water through the relief wells, the base concentration is slightly higher at relief well #707 compared to #701. The highest 2016 sample from relief well #707 indicated approximately 7,853 pCi/kg, which is less than required reporting levels.

The tritium concentrations in eight surface water sample points from 2001 through 2016 are shown in Figure 6-10. The specific sample point locations can be found in Table 2. Tritium levels in the onsite sloughs and ditches vary with the concentration in the reservoir and the amount of rainfall received. The average tritium concentration in the relief well, sloughs, and ditches are less than the reservoir because the water is diluted as it migrates through the reservoir relief well system. In 2016, six out of eight surface water sample locations tested positive for tritium.

All test results were below the United States Environmental Protection Agency drinking water limit of 20,000 pCi/kg. Rainwater was collected and analyzed during 2016 to determine if the tritium from the reservoir precipitated in the local area. Tritium was not measured in any of the rainwater samples offsite. The highest onsite rainwater sample result was 975 pCi/kg in the protected area.

Tritium was identified in the shallow (i.e. ten to thirty feet deep) aquifer test wells at Station

235 approximately seventy-five yards south of the reservoir embankment base during 1999.

Starting in 2000, samples were collected from the shallow aquifer well at Station #251 south of the Main Cooling Reservoir. The tritium results from these two shallow aquifer wells are shown in Figure 6-11. In 2016, the concentration of tritium at Station #235 was consistent with values over the past four years . Shallow aquifer tritium concentrations have remained near the concentrations found in the relief wells. Wells at Stations #258 and #259 on the west side of the site boundary have been sampled since 2006. Wells at Stations #270 and #271 were installed during the last quarter of 2008. The sample results are shown in Figure 6-12 . The well at Station

271, located adjacent to site property on a county road easement directly west of the Main Cooling Reservoir, indicated its highest concentration in 2016 at 1,419 pCi/kg. In 2016, with a maximum value of 6,820 pCi/ kg for ons ite test wells, tritium continued to remain below the United States Environmental Protection Agency drinking water limit (20,000 pCi/kg).

Tritium has not been detected in the deep aquifer that is the source of drinking water for the local communities and homes. These measurements follow the hydrological model described in the original license basis and the updated site conceptual model discussed earlier in this section.

Photo courtesy of Kenny Hilscher SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-11

Radiological Environmental Operating Report Historical Comparison of Tritium Activity in Surface Water 2001 - 2016 30,000 picoCuri es per Kilogram - Nuclea r Regulatory Commision Reporting Level 30000 E 25000 20,000 picoCuries per Kilog ram - Environmental Protect ion Agency Reporting Level

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-*c.. 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 20 15 2016 D River Sample Upstream of Plant (Offsite) #Q02 D River Sample Downstream of Plant (Offsite) #QOl D West Branch of River (Onsite) #213 D Little Robbins Slough (Onsite) #212

East Branch of Little Robbins Slough (Onsite) #211

Ditch NE of Main Cooling Reservoi r (Onsite) #229 D M ain Cooling Reservoir Blowdown (Onsite) #237 D Main Cooling Reservoir (Onsite) #216 Figure 6-10 Historical Comparison of Tritium Activity in Shallow Aquifer Ground Water 2001- 2016 E

30000 30,000 picoCuries per Kilogra m - Nuclear Regul ato ry Commision Reporti ng Level t10 25000 20,000 picoCu ries pe r Ki logram - Environmental Protection Agency Reporting Level

.!2 20000 -

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I QI

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DTest Well B-3 directly south fro m MCR (onsite) #235

Test We ll B-4 Upper Aq uifer (onsite) #251 Figure 6-11 6-12 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report Tritium Activity in Shallow Ground Water West of the Main Cooling Reservoir 2006 - 2016 5000 E 4500 bO 4000

.2 3500 S2 E ....QJ 3000

I 2500

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VI 2000 QJ

1500

I u 1000 0

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El El El D #271 M onitoring We ll #MW-080SU * #258 Pie zom et er Well #435-01

#270 Mon itoring W ell #MW-0805L D #259 Piezometer W ell #435-02 Figure 6-12 A windmill-powered groundwat er well, sample station #267, indicated tritium activity below 300 pCi/kg in 2016. This onsite ground wat er sample station is the most distant location from the Main Cooling Reservoir which has historically measured between 244 and 579 pCi/kg since fi rst detected in 2011. Th is well is not used for human con sumption.

The drinking water onsite is pumped from deep aquifer wells and is tested mont hly and composited quarterly to verify tritium is not present. The South Texas Project uses no water from the reservo ir, shallow aqu ifers or other surface water for drinking. If the water with the highest tritium concentration that leaves the site (Little Robbins Slough) was used for drinking, the maximum dose to an individual would be less than one mil Ii rem in a year. Th is dose is insignificant compared to the approximately 620 millirem the public receives a year from natural radioactivity in the environment and the radiation rece ived from medical procedures. 4 Other samples are collected and analyzed in addition to those requ ired by our licensing documents or internal procedures. These samples are collected to give additional assurance that the public and the environment are protected from any adverse effects from the plant. These samples include pasture grass, sediment samples, rain water, shallow aquifer well water, water from various ditches and sloughs onsite, direct radiation, and air samples near communities or other areas of interest. The results of these analyses indicate that plant operation has no health impact offsite and is well with in state and federal regulati ons and gu idelines.

4 NCRP (2006). Nationa l Council on Radiation Protection and Measurem ents, Ionizi ng Radiation Ex posure of th e Popu lation of the Un ited States, (Bethesda, Maryland), NCRP Report No. 160.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-13

Radiological Environmental Operating Report NEI GROUNDWATER PROTECTION INITIATIVE 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 high concentrations are sampled more frequently. Figure 6-13 contains the 2016 results for wells that were sampled along with the historical highs measured prior to 2016 for each station since sampling began in 2006. Their locations are shown in Figure 6-14.

Sample Station 2016 Measurements Historical High (well) (pCi/kg) (pCi/kg) 811 1410 1410 806 1320 1320 805 1050 1050 821 1020 1020 844 680 920 809 428 590 807 420 15300 808 less than 300 2858 801 less than 300 1150 838 less than 300 less than 300 842 less than 300 less than 300 843 less than 300 less than 300 Figure 6-13 Two wells sampled semi-annually (Stations #807 and #808) are adjacent to where a pipe was damaged and repaired several years ago. The tritium concentration at these two wells continued to decrease as expected in 2016. Station #809 tritium concentrations were related to the previously referenced pipe and subsequent repair. Station #844 tritium had a concentration of 680 pCi/kilogram and the source of that tritium is influenced by the Main Cooling Reservoir.

All the other wells sampled in 2016 that had detectable tritium are influenced by groundwater originating in the Main Cooling Reservoir. Their concentrations remain in the range of groundwater tritium concentrations associated with the Main Cooling Reservoir. All of the 2016 measurements of tritium in groundwater are only 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 6-14 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report STP PROTECTED AREA GROUND WATER MONITORING WELLS

~.

W~ E s

06-02-2015

~

TGB 1 842 Figure 6-14 Main Cooling Reservoir. Information regarding the steam traps and subsequent response was documented in the station's condition reporting process. This evaluation identified no new effluent release pathways and no impact to the drinking water or the health and safety of the public.

By the end of 2014, the majority of the protected area wells had undergone a modification to enhance the protection of the structural integrity of the water well casing used for sampling the upper aquifer. The modifications were completed in 2015 with continued improvements into 2016.

In 2016, there we re three occurrences where small amounts of condensed steam or water contacted the ground onsite. This did not result in any dose impact to the public or the environment. No discharge occurred offsite or to groundwater that may be used as a source of drinking water. Where applicable, the water was quickly recovered, recaptured, and clean up completed with no impact to groundwater.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-15

Radiological Environmental Operating Report LAND USE CENSUS The Annual Land Use Ce ns us 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 generating units. The information is used to determine whether any changes are needed in the Radiological Environment al Monitoring Program. The census is performed by contacting area residents and local government agencies that provide the information. In addition, a survey is performed to verify the nearest res idents within five miles of the South Texas Project generating units in each of 16 sectors. The results of the survey indicated no changes for 2016. The eleven sectors that have resident s within five miles and the distance to the nearest residence in each sector are listed below.

SECTOR DISTANCE (MILES} LOCATION ENE 4.5 CR 23 2 (Ryman Rd .)

ESE 3.5 Selkirk Dr.

SE 3.5 Selkirk Dr.

SW 4.5 CR 386 (Corporo n Rd .)

SSW 4. 5 CR 391 (Robbins Slough Rd .)

WSW 2.5 CR 358 w 4.5 FM 1095 WNW 4.5 CR 356 (Ashby-Bu ckeye Road)

NW 4.5 CR 354 (Mondrik Road)

NNW 3. 0 Runn ells Ranch - RM 1468 N 3.0 Runnells Ranch - RM 1468 The following items of interest were noted during the census:

No commercial dairy operates within Matagorda County.

There were no identified animals producing milk for human consumption located within five miles of STP.

A commercial olive tree orchard is located approximately 4.9 miles WSW of the plant.

Two commercial fish farms continue to operate . One is two miles west of the plant near FM 521 and the second is approximately four to five miles southwest of the plant located in the area north of Robbins Slough Road and east of South Citrus Grove Road. The water supply for the ponds is not affected by the operations of the South Texas Project.

Colorado River water from below the Bay City Dam has not been used to irrigate crops .

There were no identified commercial vegetable farms located within the five mile zone .

Broad leaf vegetation sampling is performed at the site boundary in the three most leeward sectors and at a control location in lieu of a garden census . The broad leaf vegetation samples collected also satisfy t he collection requirement when milk samples are not available.

6-16 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report 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 station's Condition Reporting Process.

The measurement capabilities of the Radiological Laboratory are demonstrated by participating in an interlaboratory measurement assurance program as well as performing duplicate and split sample analyses. Approximately 11% of the analyses performed are quality control samples .

These consist of interlaboratory measurement assurance program samples, duplicate samples, and split samples. Approximately 21% of the analyses includes National Institute of Standards and Technology samples, blanks, intercomparison testing, duplicates and splits out of a total of 1181 samples.

The interlaboratory measurement assurance program provides samples that are similar in matrix and size to those measured by the Radiological Environmental Monitoring Program .

This program assures that equipment calibrations and sample preparation methods accurately measure radioactive material in samples. Figure 6-15 summarizes the results of the interlaboratory comparison programs.

Duplicate sampling of the environment allows the South Texas Project to estimate the repeatability of the sample collection, preparation, and analysis process. Splitting samples allows estimation of the precision and bias trends of the method of analysis without the added variables introduced by sampling. Generally, two samples split from the same original sample material should agree better than two separate samples collected in the same area and time period . The 2016 variances for Duplicates and Splits are shown in Figure 6-16 .

PROGRAM DEVIATIONS 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 2016 did not impact the abilit y to demonstrate that the South Texas Project continues to operate with no negative effect on the population or the environment. During 2016, the following samples were not collected or were unacceptable for analysis:

One out of 176 direct radiation measurement samples was missed due to vandalism.

Twelve out of 265 air samples were not continuously collected for the full time interval because of loss of power or equipment failures.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-17

Radiological Environmental Operating Report 2016 Radiological Laboratory Quality Assurance Program Performance 78 Total Analyses Figure 6-15 Duplicate & Split Agreement of Environmental Samples in 2016 Air Alpha Variances 0.8%

All other variances are less than 0.01%

Figure 6-16 6-18 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM EXPOSURE: DIRECT RADIATION 40 TOTAL SAMPLING STATIONS Sample Media, Number, Approximate Location Sampling and Minimum Routine Sampling Analysis and Distance of Sample Stations from Collection Analysis Mode Type Containment. Frequency Frequency Exposure Media: TLD 16- Located in all 16 meteorological sectors, 0.2* Continuously Quarte rl y Gam ma dose Quarterly to 4 miles.

16- Located in al l 16 meteorological sectors, 2 to 7 miles.

§- Located in special interest areas (e.g. school, population centers), within 14 miles.

l- Contro l stations located in areas of minimal wind direction (WSW,ENE), 10-16 miles.

The inner ring of stations in the southern sectors are located within 1 mile becau se of the main cooling reservoir EXPOSURE: AIRBORNE 2 TOTAL SAMPLING STATIONS Sample Media, Number, Approximate Location, Minimum Routine Sampling Nominal Collection Analysis and Di stance of Sample Stations from Analysis Mode Frequency Type Containment. Frequency Charcoal and Particulate Filters 1- Located at the exclusion zone, N, NNW, NW Continuou s samp ler Weekly or more Radioiodine Weekly Sectors, 1 mile. operations frequently if Canister:

required by dust 1-131 1- Located in Bay City, 14 miles. loading Particulate 1- Control Station, located in a minimal wind Sampler:

direction (WSW), 10 miles. Gross Beta Following filter Activity change Gamma - Quarterly Isotopic of composite (by location)

MCR-STP Main Cooling Reservoir STP- South Texas Project SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-19

Radiological Environmental Operating Report TABLE 1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM {Continued)

EXPOSURE : WATERBORN E 13 TOTAL SAMP LI NG STATIONS Nominal Min imum Sample Med ia, Number And Approximate Location Routine Sampling Ana lysis Co ll ection Ana lysis of Sample Station s Mode Type Frequency Frequency Surface 1- Located in MCR at the MCR blowdown Composite samp le Monthly Gamma - Monthly structure. over a 1 month Isotopic period (grab if not 1- Located above the site on the Co lorado River available) Tritium Quarterly not influenced by plant discharge (contro l). Composite 1- Located downstream from blow down entrance into the Colorado River.

Ground Grab Quarterly Gamma - Quarterly 2- Located in we ll s used to monitor tritium Isotopic &

migration in the shallow aquifer. Tritium Drin ki ng Water 1- Located on site.

Grab Month ly Gross Beta & Monthly Gamma -

1- Located at a control station . Isotopic Tritium Quarterly Composites Sediment 1- Located above the site on the Colorado River, Grab Semiannua lly Gamma - Semiannually not in flu enced by plant discharge. Isotopic 1- Located downstream from blowdown entrance into the Colora do River.

1- Located in MCR.

No mu nicipa l water syste ms are affected by STP . This sample taken from deep aquifer supplying drinking water to emp loyees while at work.

MCR-STP Main Cooling Reservoi r STP- South Texas Project 6-20 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM (Continued)

EXPOSURE: INGESTION l TOTAL SAM PLING STATIONS Nomina l Minimum Sample Media, Number And Approximate Location Rout ine Sam pl ing Analysis Co ll ection Ana lysis of Sample Stations Mode Type Frequency Frequency Milk Grab Semi-month ly Gamma- Se mi-month ly when anim als are Isotopic w hen animals are on pa sture; And Low Level on pasture; monthly at oth er 1-131 monthly at other times . t im es.

Broad leaf Vegetation ** Grab Monthly durin g Gamma- As co 11ected growing season Isotopic l- Located at th e exclusion zone, N, NW, or (When ava il ab le)

NNW sectors.

1- Located in a mi nim al wind direction.

Fi sh and Invertebrat es (edible 1;1ortions) Grab Sam pl e semi- Gamma- As co ll ected annua lly Isotopic on 1- Representin g co mm ercia lly or recreational edib le portions important species in vici nity of STP that maybe influ enced by plant ope rati on.

1- Same or analogous species in area not influenced by STP.

1- Same or ana logous species in the MCR.

Agricultural Products Grab At time of harvest Gamma- As co 11ected Isotopic Analysis in

- - edib le portion Domestic Meat Grab Annual ly Gam ma - As co ll ected Isot opic 1- Represents domestic stock fed on crops grown exclusively within 10 miles of the pla nt.

Limited so urce of sample in vicinity of the So uth Texas Project. (Attem pts will be made to obtain sa mpl es wh en avai labl e.)

- Three different kin ds of broa d lea f vegetation are t o be col lected over th e growing season, not each coll ection period .

- - No samp le stations have bee n id entified in the vicinity of the sit e. Prese ntly no agricultural land is irri gat ed by water into which liquid plant wastes wil l be di sc harged . Agri cultura l products will be co nsid ered if these co ndition s change .

MCR-STP Main Cooling Reservoir STP- South Texas Project SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-21

Radiological Environmental Operating Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS Al AIRBORNE RADIOIODINE MG GOAT MILK AP AIRBORNE PARTICULATE Ml BEEF MEAT Bl RESIDENT DABBLER DUCK M2 POULTRY MEAT B2 RESIDENT DIVER DUCK M3 WILD SWINE B3 MIGRATORY DABBLER DUCK M4 DOMESTIC SWINE B4 MIGRATORY DIVER DUCK MS EGGS BS GOOSE M6 GAME DEER B6 DOVE M7 ALLIGATOR B7 QUAIL M8 RABBIT B8 PIGEON OY OYSTER cc CRUSTACEAN CRAB R4 TURNIP cs CRUSTACEAN SHRIMP so SOIL DR DIRECT RADIATION Sl SEDIMENT - SHORELINE Fl FISH - PISCIVOROUS S2 SEDIMENT - BOTIOM ANY COMBINATION OF BROAD LEAF F2 FISH - CRUSTACEAN & INSECT FEEDERS VB SAMPLES (Ll thru L7)

F3 FISH - PLANKIVORES & DETRITUS FEEDERS VP PASTURE GRASS L1 BANANA LEAVES WD DRINKING WATER L2 CANA LEAVES WG GROUND WATER L4 TURNIP GREENS WR RAIN WATER LS CABBAGE ws SURFACE WATER L6 COLLARD GREENS WW (relief) WELL WATER L7 MUSTARD GREENS 6-22 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS (Continued)

STATION VECTOR MEDIA CODE LOCATION CODE (Approximate)

DR Al AP VB VP SO 1 1 mile N FM 521 DR 2 1 mile NNE FM 521 DR 3 1 mile NE FM 521 DR 4 1 mile ENE FM 521 DR 5 1 mile E FM 521 Site near Rese rvoir Makeup Pumping DR Al AP SO 6 3.5 miles ESE Facility DR 7 3.5 miles SE MCR Dike DR 8 0.25 mile SSE MCR Dike DR 9 0.25 mile S MCR Dike DR 10 0.25 mile SSW MCR Dike DR 11 0.5 mile SW MCR Dike DR 12 1.5 mile WSW MCR Dike DR 13 1.5 mile W FM 521 DR 14 1.5 mile WNW FM 521 DR Al AP VB SO VP 15 1 mile NW FM 521 DR Al AP VB SO VP 16 1 mile NNW FM 521 SE corner @ intersection of FM 1468 DR 17 6.5 miles N (Buckeye RD) and CR 306 (Brown RD)

DR Al AP SO 18 5.5 miles NNE OXEA Corp. - FM 3057 DR 19 5.5 miles NE FM 2668 DR 20 5 miles ENE FM 2668 & FM 2078 DR 21 5 miles E FM 521& FM 2668 DR 22 7 miles E Lyondellbasell Chemical Plant on SH 60 DR 23* 16 miles ENE Intersection of FM 521 and FM 2540 DR 24 4 miles SSE MCR Dike DR 25 4 miles S MCR Dike DR 26 4 mil es SSW MCR Dike DR 27 2.5 miles SW MCR Dike DR 28 5 miles WSW FM 1095 & Ellis Road (CR 380)

DR SO 29 4.5 miles W FM 1095 DR 30 6 miles WNW Tres Palacios Oaks, FM 2853 DR 31 5.5 miles NW Wilson Creek Road DR 32 3.5 miles NNW FM 1468 Microwave Tower at end of Kilowatt road DR Al AP SO 33 14 miles NNE in Bay City Wadsworth Water Supply Pump Station on DR 34 7.5 miles ENE Main St.

ORAi AP SO 35 8.5 miles SSE Matagorda on Fisher St.

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 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-23

Radiological Environmental Operating Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS (Continued)

STATION VECTOR MEDIA CODE LOCATION CODE (Approximate)

DR 36 9 miles WSW College Port on FM 1095 Palacios AEP Substation on Harrison Rd .

DR Al AP VB VP SO 037

10 mil es WSW (CR 323)

AEP Substation on SH 71 near Blessing (0.2 DR 38 10.5 m iles NW miles North of SH -35)

ORAi AP SO 39 9 miles NW SH 35 under High Voltage lines DR 40 4.5 miles SW Citrus Grove Rd . (CR 385)

DR 41 2.0 miles ESE MCR Dike Site boundary just south of the sp illway DR 43 4.5 miles SE discharge channel Piezometer Wel l #446A. Alternate for WG WG 205 4.0 m iles SE is Station Code 206 WG 206 4.0 miles SE Piezomete r We ll #446 ws 209 2 mil es ESE Kelly Lake WD 210 On Site Approved drinking water supply from STP WS Sl F(l, 2, or 3) 211+ 3.5 m iles S East Branch Litt le Robbins Slough WS Sl F(l, 2, or 3) 212+ 4 miles S Litt le Robb ins Slough WSSl 213 4 miles SE West Branch Colorado River MCR at Makeup Water Discharge. Alternate F(l, 2, or 3) CC 214 2.5 miles SE for F(l, 2, or 3) in any location in the MCR MCR at Circulating Water Discharge (S2 S2 215 0.5 mile SW Alternate is any location in MCR)

WSS2 216 3.5 miles SSE MCR at blowdown structure WS S(l OR 2) F(l, 2 Mouth of Colorado River and lntracoastal 211+ 7-9 miles SSE or 3) Waterway (Region 1) 6-9 miles Co lorado River between lntracoastal WS F(l, 2 OR 3) 218+

SE-SSE Waterway and station 227 (Region 2)

Colorado River between Station 227 and WS F(l, 2 OR 3) 219 3-6 miles E-SE FM 521 (Region 3)

Co lorado River between FM 521 and the F(l, 2, or 3) 220 3-10 miles E-N LCRA Dam (Region 4)

S(l or 2) 221 >10 miles N-NE Above the LCRA Dam (Region 5)

F.(l, 2, or 3) CC 222+ >10 miles West Matagorda Bay CS-OY F(l, 2, or 3) 224 9 miles SSE West lntracoastal Canal F(l, 2, or 3) 225 9 miles SE East lntracoastal Canal West bank of Colorado River downstream WS S(l or 2) 221+ 6 miles SE of STP. Alternate for WS or S(l or 2) is station 233

+This station may be used to obtain the required aquatic samp les in the v1cin1ty of STP that may be influenced by pla nt operations.

MCR-STP Ma in Coo ling 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.

Contro l Station 6-24 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS (Continued)

STATION VECTOR MEDIA CODE LOCATION CODE (Approximate)

WD 228* 14 miles NNE Le Tu lle Park Public Water Supply on SH 35 Plant Area Drainage Ditch north of WSSl 229 2 miles ESE reservoir that empties into Colorado River Colorado River at point where drainage S(l or 2) 230+ 3.5 miles ESE ditch (#229) empties into it Colorado River approx . 0.5 km south of the S(l or 2) WS 233+ 4.5 miles SE Spillway discharge channel empties into it.

WG 235 4 miles S Well B-3 directly south from MCR B8 236 N/A STP Protected Area ws 237 3.7 miles SSE Spillway discharge channel from MCR F(l, 2, or 3) 241 <l mile S MCR circu lating water intake S(l or 2) WS 242* >10 miles N Co lorado River where it intersects SH 35 Colorado River upstream of dam at the Lower Colorado River Authority pumping ws 243* >10 miles N station near Bay City. Alternate for WS is station 242 Water well (wi ndmi ll) located on private WG 245 4.5 mile SSE property approx. 1 mile south of the MCR Drainage ditch originating at protected area WS Sl 246 <1 mi le N fence north of Un it 2 ws 247 <1 mile E Essential Cooling Pond Po int in drainage ditch north of protected WSSl 248 <l mile N area downstream of Unit #1 Protected Area storm drain discharge Control samp le purchased from a local F(l,2, or 3) CS 249* N/A retailer WG 251 4.0 miles SSE Test Well B-4, upper shal low aquife r WG 255 4.2 miles SE Piezometer Well #415 110' deep WG 256 2.8 miles ESE Piezometer Well #417 100' deep Piezometer Well #421-02, 80' deep 1.1 miles down STP Road from Station Code WG 257 3.9 miles SSW

258 approximately 20' in side east of site boundary fence Piezometer Well #435-01, 1.5 mil es down WG 258 2.9 miles SW STP Road from FM 521 along east of site boundary fence Piezometer Well #435-02, 1.5 miles down WG 259 2.9 miles SW STP Road from FM 521 20' ea st of fence (site boundary) WG Alternate is station 258 WG 260 3.7 miles S Piezometer Well #437 74' deep

+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 sati sfy collection requirement described in Tabl e 1.

Station codes typed in bold identify offsite locations.

Control Station SOUTH TEXAS PROJECT ELECTR IC GENERATIN G STATION 6-25

Radiological Environmental Operating Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS (Continued)

STATION VECTOR MEDIA CODE LOCATION CODE (Approximate)

WG 263 3.2 miles ESE Pi ezomete r Well #447 104' deep WG 264 3.2 mi les ESE Piezomete r Well #447A 46' deep WG 266 0.7 mi les NW Piezomete r Well #602A 40' deep WG 267 2.7 mi les ESE Windmill north of Heavy Haul Road WG 268 3.0 miles SE W indmill east of MCR Windmill south of STP owner cont rolled WG 269 4.2 miles SSE area on private land Monitor w ell MW-805L 49' deep. Across WG 270 2.9 mi les SW Rd from station # 258 & 259 Monitor well MW-805U Across Rd from WG 271 2.9 m iles SW station # 258 & 259 WR 272 NA Unit 1 WR 273 NA Unit 2 First catfish pond NW of plant next to FM ws 278 1.8 WNW 521 Beginning at Plant Area Discharge Ditch S(l or 2) WS 280 0.2 miles ESE (PADD) west of the Nuclear Support Center Main Spill Gate, Located north of the ws 281 0.2 miles ESE beginning of the PADD (Protected Area Drainage Ditch)

Point in drainage ditch at the Protected ws 282 <1 mile N Area storm drainage discharge pipe located West of station # 246 F(l, 2, or 3) CC S2 300 s STP Main Cooling Reservoir F(l, 2, or 3) S2 301-631 s Grids located in Main Cooling Reservoir.

WW 701 4 miles S MCR Relief Well #W-440 WW 702 4 miles S MCR Relief Well #W-500 WW 703 4 miles S MCR Relief Well #W-505 WW 704 4 miles S MCR Relief Well #W-404 WW 705 4 miles S MCR Relief Well #W-497 WW 706 4 miles S MCR Relief Well #W-522 WW 707 4 miles S MCR Relief Well #W-455 Quarterly composite of station #227 and/or ws QOl N/A alternate #233 Quarterly composite of station #243 and/or ws Q02 N/A alternate #242

+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 Rese rvoir STP- South Texas Project Med ia codes typed in bold satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

Control Station 6-26 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

A summary of all required samples is given in Table 3. The table has been formatted to resemble a United States Nuclear Regulatory Commission industry standard . Modifications have been made for the sole purpose of reading ease. Only positive values are given in this table .

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 lists the type of radioactivity or specific radionuclide for which each sample was analyzed. The second column gives the total number of analyses performed and the total number of non-routine analyses for each indicated nuclide. A non-routine 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:

The mean positive values

The number of positive measrements I 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 site's 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 2016 by 15 direct radiation measurements, 28 additional surface water samples, one additional drinking water, eight additional pasture grass, four additional rain water samples, four additional relief well water sample, one additional wild swine sample and five additional sediment samples. Fish and crustacean samples vary in number according to availability, but exceeded the minimum number required by Table 1. Also, 256 additional air station samples were collected from weekly air sample stations and 21 additional ground water samples were collected, in addition to the minimum number of samples required by Table 1 in order to strengthen the Radiological Environmental Monitoring Program.

The minimum required Radiological Environmental Monitoring Program is presented in Table 1.

The table is organized by exposure pathway. Specific requirements such as location, sampling method, collection frequency, and analyses are given for each pathway.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-27

Radiological Environmental Operating Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium : Direct Radiation Units: MilliRo entgen/Standard Qu arter ANALYSIS TOTAL ANALYSES LOWER INDICATOR LO CATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTRO L LOCATIONS TYPE fNONRO UTIN E LIM ITOF M EAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Gamma 175f 0 5.0E+OO l.3E+ol ( 163f 163 ) 1.S milesW 1.6E+ol ( 8 f 8) 1.4E+ol ( 12 f 12)

( 9.0E+OO - 1.8E+ol) (#013) (1.SE+ol - 1.8E+ol) ( l.lE+Ol - l.6E+ol) t Number of pos1t1ve measurements f total measurements at spec1f1ed locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Me dium: Airborne Particu late & Radioiodine Uni ts: Pi coCuries pe r cubic met er ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE fNONROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREM ENTS DETECTI ON RANGE INFORMATION RANG E RANGE Gross Beta 258f 0 l.4E-03 1.9E-02 ( 206 f 206 ) 1 mile NW 2.0E-02 ( Sl f 51 ) 2.0E-02 ( 52 f 52 )

( 6.6 E 4.SE-02) (#015) ( 7.4E 4.6E-02) ( 8 .3E 4.7 E-02) lodine-131 258f 0 l.lE-02 --- ( of 206 l -- -- --- ( of s2 l Cesium-134 20f 0 4.7E-04 -- ( Of 16) -- -- -- ( Of 4)

Cesium-137 20f 0 4.7E-04 -- ( Of 16) -* -- -* ( Of 4)

Manganese- 54 20f 0 5.3E-04 -- ( Of 16) -* -* -* ( Of 4) lron-59 20f 0 2.4E-03 *- ( Of 16) -* -* -* ( Of 4)

Cobalt-58 20f 0 7.7E-04 -- ( Of 16) -* -* -* ( Of 4)

Cobalt-60 20f 0 5.4E-04 -- ( Of 16) -* -* -- ( Of 4)

Zinc-65 20f 0 1.4E-03 -- ( Of 16) -* -* -* ( Of 4)

Zirconium-95 20f O l.4E-03 *- ( Of 16) -* -* -* ( Of 4)

Niobium-95 20f O 8.2E-04 *- ( Of 16) -* -* -* ( Of 4)

Lanthanum-140 20f 0 8.2E-03 -- ( Of 16) -- -- -- ( Of 4)

Barium-140 t Number of positive measurements/ total measurements at specified locations.

Photo courtesy of Rodolfo Perez 6-28 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 3 2016 RADIOLOGICAL ENVIRONM ENTAL MONITORI NG PROGRAM ANALYSIS SU MM ARY Medium : Surface Water Units: PicoCuries per Kilogram ANA LYSIS TOTAL ANALYSES LOWER IND ICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL M EAN CONTROL LOCATIONS TYPE /NONROUTINE LIMITOF ME AN t LOCATION MEAN t MEAN t MEASUREME NTS DETECTION RANGE INFORMATION RANGE RANGE Hydrogen-3 12/0 2.8E+02 9.7E+03 ( 4 I 8) 3 miles SSE 9.7E+03 ( 4 I 4) --- ( 0/ 4)

( 8.7E+03 - l.1E+04) (#216) ( 8.7E+03 - l.1E+04) lodine-131 41/ 0 4.7E+OO --- ( o I 26 I --- --- --- ( 0/ 13)

Cesium-134 41/ 0 2.0E+OO --- ( oI 26) --- --- --- ( oI 13 I Cesium-137 41/ 0 2. lE+OO --- ( oI 26) --- --- --- ( 0 / 13)

Manganese-S4 41/0 2.lE+OO --- ( oI 26) --- --- --- ( oI 13) lron-S9 41/ 0 4.8E+OO --- ( 0 / 26) --- --- --- ( oI 13 I Cobalt-SB 41/ 0 2.2E+OO --- ( oI 26) --- --- --- ( oI 13 J Cobalt-60 41/ 0 2.2E+OO --- ( oI 26) --- --- --- ( oI 13)

Zinc-6S 41/0 4.7E+OO --- ( 0/ 26) --- --- --- ( 0 / 13)

Zirconium-95 41/0 3.7E+OO --- ( 0/ 26) --- --- --- ( oI 13 J Niobium-95 41/ 0 2.lE+OO --- ( 0/ 26) --- --- --- ( oI 13 J Lanthanum-140 41/ 0 4.7E+OO -- ( o I 26 J -- --- --- ( oI 13)

Barium-140 t Number of pos1t1ve measurements/ total measurements at spec1 f1ed locations.

TABLE 3 2016 RAD I OLO G ICAL ENVI RO NM EN TAL M O NITOR I NG PROG R A M ANALYSIS SUMM ARY Medium: Ground Wate r (On site test well) Un its: PicoCuries p e r Ki lo g ram ANALYSIS TOTAL ANALYSES LOWER INDI CATO R LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTRO L LOCATIONS TYPE f NONROUTINE LIMITOF MEAN t LOCATION MEAN + MEAN t MEASUREME NTS DETECTION RANGE INFORMATIO N RANGE RANGE Hydrogen-3 22f 0 2.8E+02 4.3E+o3 ( 14 f 22 ) 4.0 miles SSE 6 .3 E+03 ( 4f 4) no samples

( 2.6E + 03 - 6.8E+o3 ) (#251) ( S.7E+o3 - 6.8E+03 )

lodine-1 31 22f 0 3.SE+OO -- ( Of 22) -- -- no samp les Cesi um -134 22f 0 2.7E+OO -- ( Of 22) -- -- no sa mples Cesium-137 22f O 2.8E+OO -- ( Of 22) -- -- no samples Ma n ganese-54 22f O 2.GE+OO -- ( of 22) -- -- n o sa mpl es lron-59 22f0 5.SE+OO -- ( Of 22) -- -- n o samples Co balt- 58 22f O 2.7E+o0 --- ( Of 22) -- -- no samples Co b alt-60 22f O 2.SE+oO --- ( Of 22) -- -- no samples Zi nc-65 22f 0 7.lE+oO --- ( of 22) -- -- no samples Z irconium -95 22f 0 4 . SE+oO --- ( o f 22) -- -- n o sa mpl e s Niobium-95 22f 0 2.9E+o0 --- ( of 22 l -- -- no samp les Lanthanum-140 22f 0 4 .lE+oO --- ( of 22 l -- -- no samples Barium-140 t Number of positi ve mea surement s/ total measurements at spec1f1ed locations.

SO UTH TEXAS PROJ ECT ELECTRI C GENE RATING STATION 6-29

Radiological Environmental Operating Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Rain Water Units: PicoCuries per Kil ogram ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WI TH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE f NONROUTINE LIM ITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANG E RANGE Hydrogen-3 4f O 2.8E+02 --- ( of 4 l -- -- no samples lodine-131 4f0 3.lE+OO --- ( of 4 l -- -- no samples Cesium-134 4f0 2.7E+OO --- ( of 4 l -- -- no samples Cesium-137 4f 0 2.8E+OO --- ( of 4 l -- -- no samples Manganese- 54 4f0 2.8E+OO --- ( of 4 l -- -- no samples lron-59 4f0 5.6E+OO --- ( of 4 l -- -- no samples Cobalt-58 4f0 2.7E+OO --- ( of 4 l -- -- no samples Cobalt-60 4f 0 3 .l E+OO --- ( of 4 l -- -- no samples Zinc-£5 4f0 6.2E+OO --- ( of 4 l -- -- no samples Zircon ium-95 4f O 4.8E+OO --- ( of 4 l -- -- no samples Niobium-95 4f O 2.9E+OO --- ( Of 4) -- -- no samples Lanthanum-140 4f0 4.2E+OO --- ( Of 4) -- -- no samples Ba rium-140 t Number of pos1t1ve measurements I total measurements at spec1f1ed locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Drink ing Water Units: PicoCuri es per Kilogram ANALYSIS TOTAL ANALYSES LOWER IN DI CATOR LOCATIONS LOCATION W ITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE fNONROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANG E RANGE Gross Beta 25f 0 1.0E+OO 2.2E+DO ( 13 f 13) 14 mile s NNE 7.lE+OO ( 12 f 12 ) 7.lE+DO ( 12 f 12 )

( l.2E+OO - 3.8E+DO) (#228) ( 4 .6E+DO- 1.2E+Ol ) ( 4.6E+DO - 1.2E+Dl)

Hydrogen-3 8f0 2.8E+02 --- ( of 4) -- -- -- ( Of 4) lodine-131 25f 0 3.6E+OO -- ( Of 13) -- -- --- ( of 12 l Cesium-134 25f 0 2.7 E+OO -- ( Of 13) -- -- --- ( of 12)

Cesium-137 25f O 2.8E+OO -- ( Of 13) -- -- --- ( of 12 l Manganese-54 25f 0 2.8E+OO -- ( Of 13) -- -- --- ( of 12) lron-59 25f 0 5.7E+OO -- ( Of 13) -- -- --- ( of 12 l Cobalt-58 25f 0 2.7E+OO -- ( Of 13) -- -- --- ( of 12)

Cobalt-60 25f 0 2.9E+OO -- ( Of 13) -- -- --- ( of 12 l Zinc-£5 25f 0 7.SE+OO -- ( Of 13) -- -- --- ( of 12)

Zi rconium-95 25f 0 4.6E+OO -- ( Of 13) -- -- --- ( of 12)

Niobium-95 25f 0 2.9E+OO -- ( Of 13) -- -- --- ( of 12)

Lanthanum-140 25f 0 4.3E+OO -- ( Of 13) -- -- --- ( of 12)

Ba rium-140 t Number of poS1t1ve measurements f total measurements at spec1f1ed locations.

6-30 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium : Sedim ent-Sho reline Units: PicoCuri es per Kilogram dry we ight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NONROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RAN GE IN FORMATION RANGE RANGE Cesiu m-134 4/0 2.lE+Ol --- ( o I 2 l -- --- -- ( 0/ 2)

Cesium-137 4/0 2.3E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2 )

Manganese-54 4/0 2.4E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2) lron-59 4/0 7.9E+Ol --- ( o I 2 l -- -- -- ( 0/ 2)

Cobalt-58 4/0 2.8E+Ol --- ( oI 2 l -- -- -- ( 0/ 2)

Cobalt-60 4/0 2.4E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2)

Zinc-65 4/0 7.3E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2)

Zirconium-95 4/ 0 5.4E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2)

Niobium-95 4/ 0 3.4E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2)

Lanthanum-140 4/ 0 2.0E+02 --- ( 0 / 2) -- -- -- ( 0/ 2)

Barium-140 t Number of pos1t1ve measurements I total measurements at spec1f1ed locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Sediment-Bottom Units: PicoCuri es per Kilo gram dry weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION W ITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 7/ 0 2.SE+Ol --- ! o I 7 l -- -- no samples Cesiu m-137 7/ 0 2.3E+Ol 7.6E+ol ( 7 I 7 ) 3 miles SSE 1.0E+02 ( 3 I 3) no sa mples

( 3.6E+Ol - 1.0E+o2) (#216) ( 9.5E+ol - l.OE+02 )

Manganese-54 7f0 2.9E+Ol --- ( o I 7 l -- -- no samples lron-59 7/ 0 8.7E+Ol --- ( Of 7) -- -- no sa mples Cobalt-58 7/ 0 3.lE+Ol --- ( 0/ 7) -- -- no samples Cobalt-60 7f 0 2.4E+Ol 6.3E+ol ( 7 f 7 ) 1 mile SW 6.5E+Ol ( 4 f 4 ) no sa mples

( 3.9 E+Ol - 9.6E+ol ) (#215) ( 3.9E+ol - 9.6E+Ol)

Zinc-65 7/ 0 8.lE+Ol --- ( Of 7) -- -- no samples Zirconium-95 7f0 6.lE+Ol --- ( Of 7) -- -- no samples Niobium-95 7f 0 3.9E+Ol --- ( Of 7) -- -- no sa mples Lanthanum-140 7f 0 l.8E+02 --- ( Of 7) -- -- no samples Barium-140 t Number of pos1t1ve measurements I total mea surements at spec1f1ed locations.

Photo courtesy of Aubrey Passafuma SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-31

Radiological Environmental Operating Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Ba nana Leaves Units: Pi coCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER INDI CATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE fNONRO UTINE LIMI T OF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE lodi ne-131 22f 0 1.6E+Ol --(Of15) -- -- --(Of7)

Cesium-134 22f 0 1.2E+Ol -- ( Of 15) -- -- -- ( Of 7)

Cesium-137 22f 0 1.3E+Ol -- ( Of 15) -- -- -- ( Of 7)

Manganese-54 22f 0 1.3E+Ol -- ( Of 15) -- -- -- ( Of 7) lron-59 22f 0 3.4E+Ol -- ( Of 15) -- -- -- ( Of 7)

Cobalt-58 22f 0 1.3E+Ol -- ( Of 15) -- --- --- ( Of 7)

Cobalt-60 22f 0 1.6E+Ol -- ( Of 15) -- -- -- ( Of 7)

Zinc-65 22f 0 4.lE+Ol -- ( Of 15) -- -- -- ( Of 7)

Zirconium-95 22f O 2.2E+Ol -- ( Of 15) -- -- -- ( Of 7)

Niobium-95 22f O 1.4E+Ol -- ( Of 15) -- -- -- ( Of 7)

Lanthanum-140 22f 0 1.7E+Ol -- ( Of 15) -- -- -- ( Of 7)

Ba rium-140 t Number of positive measurements f total measurements at specified locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Ca na Leaves Units: PicoCuries per Ki logram wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE fNONROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE lodine-131 9/0 1.SE+Ol --- ( 0/ 6) -- -- -- ( 0/ 3)

Cesiu m-134 9f 0 l.lE+Ol --- ( 0/ 6) -- -- -- ( 0/ 3)

Cesium-137 9/ 0 1.2E+Ol --- ( oI 6 l -- -- -- ( 0/ 3)

Manganese-54 9f 0 1.3E+Ol --- ( oI 6 l -- -- -- ( 0/ 3) lron-59 9/0 2.9 E+Ol --- ( 0/ 6) -- -- -- ( 0/ 3)

Cobalt-58 9/ 0 1.2E+Ol --- ( 0/ 6) -- -- -- ( 0/ 3)

Cobalt-60 9/ 0 1.4E+Ol --- ( oI 6 l -- -- -- ( 0/ 3)

Zinc-65 9/0 3.5E+Ol --- ( of 6 l -- -- -- ( Of 3)

Zirconium-95 9f O l.9E+Ol --- ( of 6 l -- -- -- ( Of 3)

Niobium-95 9/ 0 l.2E+Ol --- ( of 6 l -- -- -- ( Of 3)

Lanthanum-140 9f 0 l .5E+Ol --- ( oI 6 l -- -- -- ( 0/ 3)

Barium-140 t Number of positive measurements I total measurements at specified locations.

6-32 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medi um : Col la rd Greens Uni ts: PicoCuri es per Kilogra m wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE / NON ROUTINE LIMITOF MEAN t LOCATI ON MEAN t MEAN t MEASUREMENTS DET ECTION RANGE INFORMATION RANGE RANGE lodine-131 6/ 0 l.3E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Cesium-134 6/ 0 l.2E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Cesium-137 6/ 0 l .2E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Manganese-54 6/ 0 l .2E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2) lron-S9 6/0 2.8E+Ol --- ( 0/ 4) -- -- -- ( 0 / 2)

Cobalt-58 6/0 l.3E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Cobalt-60 6/ 0 1.4E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Zi nc-6S 6/0 3.6E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Zirconium -9 5 6/0 2.0E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Niobium-95 6/0 l.2E+Ol --- ( 0/ 4) -- -- -- ( 0/ 2)

Lanthanum-140 6/0 l .6 E+Ol --- ( 0 / 4) -- -- -- ( 0/ 2 )

Barium-140 t Number of pos1t1ve mea surements I total mea surements at spec1f1ed locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Fish - Piscivorous Units: PicoCuries per Kilogram wet weigh t ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGH EST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 9/0 3.lE+Ol --- ! oI 9l -- -- no sam ples Cesium-137 9/0 3.lE+Ol --- ( 0/ 9) -- -- no samples Manganese-54 9/0 3.3E+Ol --- ! oI 9l -- -- no sa mples lron-59 9/0 9.5E+Ol --- ! oI 9l -- -- no samples Cobalt-58 9/0 3.8E+Ol --- ! oI 9l -- -- no samples Cobalt-60 9/ 0 3.6E+Ol --- ! o I 9l -- -- no sa mples Zinc-65 9/ 0 7.9E+Ol --- ! oI 9l -- -- no sa mples Zirconium-95 9/ 0 6.8E+Ol --- ! oI 9l -- -- no sa mples Niobium-95 9/ 0 4.0E+Ol --- ! oI 9l -- -- no samples La nt hanum-140 9/ 0 l.9E+02 --- ! oI 9 l -- -- no sam ples Barium-140 t Number of pos1t1ve measurements I total measurements at spec1f1ed locations.

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-33

Radiological Environmental Operating Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Fish - Crustacean & Insect Feeders Units: PicoCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER INDI CATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NONROUTI NE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 5/ 0 3.0E+Ol --- ! oI 2l -- -- -- ( 0/ 3)

Cesium-137 5/ 0 3.0E+Ol --- ( oI 2 l -* -* -* ( 0/ 3)

Ma nganese-54 5/ 0 3.l E+Ol *** ! oI 2l -* -* -- ( 0/ 3) lron-59 5/ 0 8.8E+Ol --- ! oI 2) -* -- -* ( 0/ 3)

Cobalt-58 5/ 0 3.4E+Ol *** ! oI 2l -- -- -* ( 0/ 3)

Coba lt-60 5/ 0 3.SE+Ol *** ! oI 2l -- -- -- ( 0/ 3)

Zinc-SS 5/ 0 8.lE+Ol *** ! oI 2l -- -- -- ( 0/ 3)

Zirco nium-95 5/0 6.lE+Ol *** ! oI 2l -* -- -- ( 0/ 3)

Niobium-95 5/ 0 3.5E+Ol *** ! oI 2l -- -- -* ( 0/ 3)

Lanthanum-140 5/0 l.3 E+02 *** ! oI 2 l -* -- -* ( 0/ 3)

Barium-140 t Number of pos1t1ve measurements I total measurements at spec1f1ed locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium : Crustacean Shrimp Units: PicoCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NONROUTI NE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 4/0 3.4E+Ol --- ( o I 2 l -* -* -* ( 0/ 2)

Cesi um-137 4/0 3.4E+Ol -** ( 0/ 2) ... -- -* ( 0/ 2)

Manganese-54 4/0 3.SE+Ol ... ( 0/ 2) -- -- -- ( 0/ 2) lron-59 4/ 0 9.lE+Ol --* ( o I 2 l -- -- -- ( 0/ 2)

Cobalt-SB 4/ 0 3.7E+Ol --* ( oI 2 l -- -- -* ( 0/ 2)

Coba lt-60 4/ 0 3.7E+Ol --- ( o I 2 l -- -- -- ( 0/ 2)

Zinc-Q5 4/0 8.0E+Ol --- ( oI 2 l -- -- -- ( 0/ 2)

Zirconium-95 4/0 6.9E+Ol --- ( 0/ 2) -- -- -- ( 0/ 2)

Niobium-95 4/ 0 4.2E+Ol --- ( o I 2) -- -- -- ( 0/ 2)

Lanthanum-140 4/0 l.6E+02 --- ( 0/ 2) -- -- -- ( 0/ 2)

Barium-140 t Number of pos1t1ve measurements/ total measurements at spec1f1ed locations.

6-34 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

2016 Environmental Report TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Beef Meat Units : PicoCuries per Kilogra m wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE f NONROUTINE LIMIT OF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 2f0 2.9E+Ol --- ( of 2 l -- -- no samples Cesium-137 2f0 2.9E+Ol --- ( Of 2) -- -- no sa mples Manganese-54 2f0 3.2E+Ol --- ( of 2 l --- -- no samples lron-59 2f0 9.0E+Ol --- ( Of 2) -- -- no samples Cobalt-58 2f0 3.5E+Ol --- ( Of 2) -- -- no samples Cobalt-60 2f0 3.2E+Ol --- ( Of 2) -- -- no sa mples Zinc-65 2f 0 7.2E+Ol --- ( of 2 l -- -- no sa mples Zirconium-95 2f 0 6.5E+Ol --- ( of 2 l -- -- no samples Niobium-95 2f 0 3.7E+Ol --- ( Of 2) -- -- no sampl es Lanthanum-140 2f 0 2.2E+02 --- ( Of 2) -- -- no sa mples Barium -140 t Number of pos1 t1 ve measurements f total measurements at spec1f1ed locations.

TABLE 3 2016 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium : Wild Swine Units: PicoCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION W ITH HIGHEST ANNUAL M EAN CONTROL LOCATIONS TYPE / NONROUTINE LI MITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesi um -134 1/ 0 3.7E+Ol --- ( 0/ 1) -- -- no samples Cesium-137 1/ 0 3.9E+Ol --- ( Of 1) -- -- no samples Manganese-54 1/ 0 3 .8E+Ol --- ( Of 1) -- -- no samples lron -59 1/ 0 8.2E+Ol --- ( 0/ 1) -- -- no sa mpl es Cobalt-SB 1/0 4.0E+Ol --- ( 0/ 1) -- -- no samples Cobalt-60 1/ 0 3.SE+Ol --- ( 0/ 1) -- -- no samples Zinc-65 1/ 0 8.4E+Ol --- ( 0/ 1) -- -- no samples Zi rconium-95 1/ 0 7 .2 E+Ol --- ( 0/ 1) --- -- no sa mple s Niobium-95 1/ 0 4.4E+Ol --- ( Of 1) -- -- no sa mples Lanthanum-140 1/ 0 l.2E+02 --- ( 0/ 1) -- -- no samples Barium-1 40 t Number of pos1t1ve measurements/ total measurements at spec1f1ed locations.

Photo courtesy of Aubrey Passafi1ma SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION 6-35

Photo courtesy of Kenneth Hilscher 6-36 SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION

SOUTH TEXAS PROJECT ELECTRIC GENERATING STATION L

NOC-AE-17003467, Submittal of 2016 South Texas Project Electric Generating Station Annual Environmental Operating Report

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NOC-AE-17003467, Submittal of 2016 South Texas Project Electric Generating Station Annual Environmental Operating Report

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