Text

Transmittal of 2015 Annual Environmental and Annual Radiological Environmental Operating Reports
	ML16125A209
Person / Time
Site:	South Texas
Issue date:	04/27/2016
From:	Aguilera R; South Texas
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	NOC-AE-16003372, STI: 34311398
	Download: ML16125A209 (79)
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South Texas Project Electric Generating Station P.O. Box 289 Wadsworth, li:xas 77483 April 27, 2016 NOC-AE-16003372 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 ar:id 2 Docket Nos. STN 50-498, STN 50-499 2015 Annual Environmental arid Annual Radiological Environmental Operating Reports Pursuant to South Texas Project Unit 1 Operating License NPF-76 and Unit 2 Operating License NPF-80 Appendix B, Environ'mental Protection Plan (Non-radiological), and Technical Specification 6.9.1.3, the STP Nuclear Operating Company provides the attached 2015 Annual Environmental and Annual Radiological Environmental Operating Reports.

There are no commitments included in this report.

If there are any questions, please contact either Marilyn Kistler at (361) 972-8385 or me at (361) 972-8679.

MK

Attachment:

2015 Arinual Environmental and Annual Radiological Environmental Operating Reports STI: 34311398

NOC-AE-16003372 Page 2 of 2 cc: (electronic. copy)

(paper copy)

Morgan, Lewis & Bockius LLP Regional Administrator, Region IV Steve Frantz, Esquire U.S. Nuclear Regulatory Commission 1600 East Lamar Boulevard u.s: Nuclear Regulatory Commission Arlington, TX 76011-4511 Lisa M. Regner Lisa M. Regner Senior Project Manager NRG South Texas LP U.S. Nuclear Regulatory Commission Chris O'Hara One White Flint North (08H04) Jim von Suskil 11555 Rockville Pike Skip Zahn Rockville, MD 20852 NRC Resident Inspector, CPS Energy U. S. Nuclear Regulatory Commission Kevin Pollo P. 0. Box 289, Mail Code: MN116 Cris Eugster Wadsworth, TX 77483 L. D. Blaylock Matagorda County Judge Nate McDonald Crain Caton & James. P.C.

1700 7th Street Rm 301 Peter Nemeth Bay City, Texas 77414 Commissioner Pet. 1 City of Austin Daniel Pustka Elaina Ball 2604 Nichols Road John Wester Bay City, Texas 77414 Commissioner Pet. 2 Texas Dept. of State Health Services Kent Pollard Helen Watkins Box 571 Robert Free Matagorda, Texas 77 457 Commissioner Pet. 3 James Gibson 1200 Perryman Ave.

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

Attachment South Texas Project Units 1and2 2015 Annual Environmental and Annual Radiological Environmental Operating Reports

The 2015 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: Raihan Khondker Maps provided by Janice Hopes Photography performed by: Cheryl Bentley, Sandy Dannhardt, Gene Fisseler, Rodger Harris, Kenny Hilscher, Jodie Jankauskas, Raihan Khondker, Nancy Kubecka, Aubrey Passafuma, Gary Parkey, Rudy Perez, Pam Reis, Bill Sansing, John Savage, Robyn Savage and Gary Zink STP Nuclear Operating Company

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

NPF-76 and NPF-80 April 2016 Authored by:

Laura Stoicescu Staff Health Physicist Radiation Protection and P~ft&?z~

Environmental Supervisor Regulatory Affairs Technical Review:

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

Roger A. Aguilera V Manager Radiation Protection

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2015 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 Assur.ance .......................................................................................... 6-17 Program Deviations ........................................................................................ 6-17 2015 Radiological Environmental Monitoring Program Analysis Summary ... 6-27 List of Figures Figure 2-1: Plant Water Systems................................................................. 2-4 Figure 4-1: 2015 Nonradioactive Waste Management............................... 4~9 Figure 4-2: 2015 Nonradioactive Waste Generation .................................. 4-10 Figure 4-3: Hazardous Waste Shipped Historical Comparison .................... 4-10 STP Nuclear Operating Company

2015 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: 2015 Radiological Laboratory Quality Assurance Program Performance ....................................... ........... .... ............... 6-18 Figure 6-16: Duplicate & Split Agreement of Environmental Samples in 2015 ... 6-18 List of Tables Table 1: Radiological Environmental Monitoring Program ........................... 6-19 Table 2: Sample Media and Location Descriptions ....................................... 6-22 Table 3: 2015 Radiological Environmental Monitoring Program Analysis Summary ............................................ ............................... 6-28 STP Nuclear Operating Company

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Executive Summary The 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 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 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 monitoring programs, radiological and nonradiological, conducted at the South Texas Project during 2015. 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 conditions. In 2015, nonradiological 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 specified minimum limits for certain types of samples. This ensures that radiation measurements are 1-2 STP Nuclear Operating Company

2015 Environmental Report 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 2015 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 only 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 than 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 2015. 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, cobalt-60 and cesium -137, were detected in the reservoir sediment this year at designated sample locations at very low concentrations. Additional samples had detectable cesium-137 consistent with preoperational concentrations and which is normally present in the environment. Onsite sediment samples continue to occasionally indicate traces of plant-related nuclides such as cobalt-60. Offsite sediment samples continue to show no radioactivity from the South Texas Project. In summary, the station produces 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, preoperational measurements and continue to show no effect from plant 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.

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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 Electric Generating Station is owned by NRG South Texas LP, City of Austin, and City Public Service Board of San Antonio as tenants in common. Houston Lighting & Power Company was the original project manager of the South Texas Project and was responsible for the engineering, design, licensing, construction, startup, and initial commercial operation of the two-unit facility.

In 1997, the STP Nuclear Operating Company assumed operational control of the South Texas Project and responsibility for implementation of associated environmental programs.

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. 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. The process for preparation of the final supplemental impact statement included consultation with other applicable regulating agencies, review of information provided by the South Texas Project, the Nuclear Regulatory Commission's own independent environmental review and consideration of public comments received during the process. In September of 2007, a Combined Construction and Operating License Photo courtesy of Nancy Kubecka 2-2 STP Nuclear Operating Company

2015 Environmental Report 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. The process for preparation of the final impact statement included consultation with other applicable regulating agencies, review of information provided by the South Texas Project, the Nuclear Regulatory Commission's own independent environmental review and consideration of public comments received during the process. In November of 2015, the United States Nuclear Regulatory Commission held a hearing on the combined license application to construct and operate two new nuclear reactors at the South Texas Project site in Matagorda County,Texas. Issuance of the combined licenses was subsequently authorized February 12, 2016.

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 Project, 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 reservoir turns 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.

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Site and Area Description PLANT WATER SYSTEMS SECONDARY LOOP PRESSURIZER CONDENSATE 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 that would 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 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 2014, the most recent year for which data is available, nuclear generation in the United States prevented 595.03 million metric tons of carbon dioxide, 0.96 million short tons of sulfur dioxide, and 0.48 million short tons of nitrogen oxide from entering the Earth's atmosphere. 1 Nuclear power plants also generated approximately 63 percent of all clean-air electricity in the United States in 2014. 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. Em issions Avoided by the U.S. Nuclear Industry. http://www.nei.org/KnowledgeCenter/

Nuclear-Statistics/Environment-Emissions-Prevented/ Emissions-Avoided -by-the-US-Nuclear-Industry. May 2015.

2 Nuclear Energy Institute . Environment: Emissions Prevented . http ://www.nei .org/Knowledge-Center/Nucle-arStatistics/Environment-Emissions-Prevented . Sources of Emission -Free Electricity lnfographic (2014) . Viewed on February 28, 2016.

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2015 Environmental Report THE PLANT SITE Sixty-five of the total 12,220 acres at the South Texas Project are occupied by the two current power plants. Plant facilities include a 7,000-acre main cooling reservoir and a 47 -acre essential cooling pond. Many smaller bodies of water onsite include wetlands, Kelly Lake, drainage ditches, sloughs, and depressions. Much of the land east of the cooling reservoir is leased for cattle grazing. Approximately 1,700 acres remain in a more natural state as a lowland habitat. A 110-acre wetland habitat area was established in 1996 on previously unused land located northeast of the power plants. The area surrounding the South Texas Project is characterized by coastal plain with farmland and pasture predominating. Local 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 and the common tern, 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. Drought conditions continued in Texas for much of 2015, however, the state was practically drought free by the end of the year. 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 Bill Sansing STP Nuclear Operating Company 2-5

Site and Area Description Photo courtesy of Gene Fisseler 2-6 STP Nuclear Operating Company

Nonradiological Environmental Introduction and Summary Nonradiological environmental conditions and performance at the South Texas Project during 2015 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 2015.

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 is illustrated by the following successes in 2015 .

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;

Successful renewal of the station's wastewater discharge permit; and,

Continued emphasis on waste minimization and source reduction allowing the station to maintain its classification as a small quantity generator of industrial waste.

Everyone 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.

Photo courtesy of Raihan Khondker 3

Per Compliance History Report for CN601658669, RN102395654, Rating Year 2015; as prepared by the Texas Com-mission on Environmental Quality on January 27, 2016.

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2015 Environmental Report Photo courtesy of Gene Fisseler STP Nuclear Operating Company 3-3

Photo courtesy of Raihan Khondker 3-4 STP Nuclear Operating Company

Nonradiological Environmental Operating Report ENVIRONMENTAL CONDITIONS This section of the report describes the South Texas Project's nonradiological environmental program performance and environmental conditions from January 1 through December 31, 2015.

The STP Nuclear Operating Company closely monitors environmental conditions and performance 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 two air quality permit compliance file reviews in 2015.

The Texas Commission on Environmental Quality rated the South Texas Project as a high performer in 2015 based on the station's environmental compliance record . Facilities, such as the South Texas Project, are 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 Projec't 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 organ izations, co-sponsored and participated in the annual Matagorda County Household Hazardous Waste Collection Day in the fall of 2015, and station employees also participated in other community area environmental projects such as the county's 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 2015 sponsored by federal and state agencies and volunteer organizations such as the annual National Audubon Society Christmas Bird Count, the Great Texas Birding Classic, and the United States Fish and Wildlife Service 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 bottom land 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 2015 remained generally unchanged and satisfactory.

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, which includes the South Texas Project, consistently ranks at or near the top of the National 4-2 STP Nuclear Operating Company

2015 Environmental Report Audubon Society's annual Christmas Bird Count for the number of species identified. Several 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 by station and NRG Energy, Inc. personnel 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. Photo courtesy of Pam Reis STP Nuclear Operating Company 4-3

Nonradiological Environmental Operating Report 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 pumping periods. Surface water diverted to the Main Cooling Reservoir from the Colorado River accounted for almost 98 percent of the water used at the South Texas Project in 2015. 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. The South Texas Project diverted 66,355 acre-feet in 2015 from the Colorado River for intermittent Main Cooling Reservoir fill operations as conditions allowed, mainly in the second quarter of the year following improved drought conditions, while preserving adequate freshwater flow conditions for downstream bay and estuarine ecosystems. Approximately two percent, or 1,099 acre-feet, of the water used by the station was withdrawn from onsite groundwater sources in 2015.

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 station meets the stringent levels set in the permit. A monthly monitoring report is submitted to the Texas Commission on Environmental Quality for wastewater discharges. In 2014, the South Texas Project applied for a renewal of this wastewater discharge permit and the renewed permit was issued by the state in April of 2015. Reports identifying groundwater use, surface water use and water conservation are submitted annually to the Texas Water Development Board . Reports of 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.

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2015 Environmental Report 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 reservoir in 2015. Station conditions neither required site aquatic monitoring studies be conducted in 2015, nor were any additional studies required by the United States Environmental Protection Agency or the State of Texas either by way of station discharge permits or otherwise. Wastewater discharges met state and federal water quality standards during the year, while conserving and maximizing efficient water usage at the station.

In addition to the wastewater discharge permit program, the Federal Clean Water Act, as amended, requires permits for storm water discharges associated with industrial activity. The South Texas Project Storm Water Pollution Prevention Plan ensures that potential pollution sources at the site 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 working 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.

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 commenced in 2011 and will conclude 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 will be incorporated into the state water plan which will be 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 athttp://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 STP Nuclear Operating Company 4-5

Nonradiological Environmental Operating Report 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/.

In 2007, in further recognition of the importance of water conservation to meet future demands in the state, Senate Bill 3, enacted by the Texas Legislature, created a stakeholder-driven process for the development of environmental flows. Environmental flows are the amount of water necessary for a river, estuary, or other freshwater system to maintain its health and productivity.

The law established 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. The South Texas Project participates as a member of the stakeholder committee that includes the Colorado River and Matagorda Bay. In August of 2011, the stakeholder committee recommendations for the Colorado River Basin were submitted to the Texas Commission on Environmental Quality. The commission, after considering these recommendations along with public input, adopted formal environmental flow standards that must be maintained. 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. As a follow up to the initial flow recommendations, the stakeholder committee submitted a Draft Work Plan to the Texas Commission on Environmental Quality in June of 2012. The Draft Work Plan addressed additional efforts needed for research and data development to support a planned review of the environmental flow standards in 2021. In 2013, the stakeholder committee evaluated and recommended additional environmental studies for the Matagorda Bay and Estuaries and subsequently submitted this recommendation to the Texas Water Development Board for approval and funding. Accordingly, additional field studies were initiated and conducted in 2014 and 2015.

The existing South Texas Project surface water diversion right is not impacted by this legislation.

Additional information regarding environmental flows can be found at http://www.tceq.texas.gov/

permitting/water_supply/water_rights/eflows/.

In January 2010, the Texas Commission on Environmental Quality approved a revised Lower Colorado River Authority Water Management Plan. The 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. As part of the January 2010 approval of the revised Water Management Plan, the Texas Commission on Environmental Quality directed the Lower Colorado River Authority to file an application to revise the Water Management Plan no later than July of 2013. To assist with this update, 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 advisory committee started in July 2010 and completed its recommendations in late 2011. The South 4-6 STP Nuclear Operating Company

2015 Environmental Report Texas Project represented industrial firm water customers on the advisory committee. The Lower Colorado River Authority Board of Directors approved the revised plan in 2012 and forwarded it to the Texas Commission on Environmental Quality for final approval. The Texas Commission on Environmental Quality subsequently determined that it was necessary to update the plan to include more recent drought data. The Lower Colorado River Authority filed an amended application incorporating the updated data with stakeholder input in 2014. The Texas Commission on Environmental Quality approved the plan in November 2015. Additional information on the Water Management Plan can be found at http://www.lcra.org.

In 1999, the South Texas Project developed, submitted and implemented an initial 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. Plans are 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 use of water resources and reduction of water waste.

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 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-fuel 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 2015, one excess opacity event occurred and was reported to the Texas Commission on Environmental Quality. This event was associated with visib.le emissions resulting from a grass fire that occurred in August of 2015 as a result of a lightning strike that damaged an electric power line.

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. 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 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

STP Nuclear Operating Company 4-7

Nonradiological Environmental Operating Report 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 July 2015. The permit is required to be amended to incorporate new emission sources if added. The station notified the Texas Commission on Environmental Quality of the installation of four new emergency diesel generators and associated fuel supply tanks in 2015.

The applicable requirements associated with these changes will be incorporated into the permit during the renewal process. 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. Two deviations were identified in 2015. In addition to the visible emission event discussed earlier in this section, a second deviation associated with a small, non-reportable halon emission from a fire protection system occurred in August of 2015.

Both deviation events will be included in the station's semi-annual deviation report to the Texas Commission on Environmental Quality in accordance with applicable permit requirements. In addition, two offsite file reviews were completed by the Texas Commission on Environmental Quality in 2015 for compliance with applicable requirements for air quality as identified in the station's Federal Operating Permit. Following the offsite file review conducted in February 2015, the Texas Commission on Environmental Quality issued two minor violations for recordkeeping and reporting deviations associated with gaps in a continuous strip chart record of auxiliary boiler flue gas content that were self-identified and included in the station's semi-annual deviation reports in 2013. No emission limits were exceeded. Both violations were categorized by the state as minor and the corrective actions implemented in 2013 were considered adequate. The Texas Commission on Environmental Quality required no further actions. A second offsite file review was completed in November 2015. No findings or violations were identified.

Unlike conventional electrical generating stations, nuclear power plants do not burn fossil fuel for production of electricity. Therefore, the South Texas Project produces virtually no greenhouse gases or other 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.

NONRADIOACTIVE WASTE MANAGEMENT Solid waste management procedures for hazardous 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.

4-8 STP Nuclear Operating Company

2015 Environmental Report 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 2015 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. Plant personnel routinely inspect areas throughout the site to ensure wastes are not stored or accumulated inappropriately.

Station 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 95 percent of the industrial nonradioactive waste generated in 2015 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 are sent to a recycling vendor for reprocessing. Empty polyethylene drums are returned, when possible, to the original manufacturer for reuse. Non-hazardous blast grit and construction 2015 Nonradioactive Waste Management South Texas Project Recycle 94.63%

Landfill 2.94%

Incineration &

Fuel Blending Treatment 0.54%

1.89%

Figure 4-1 STP Nuclear Operating Company 4-9

Nonradiological Environmental Operating Report 2015 Nonradioactive Waste Generation South Texas Project Non-Hazardous Waste 99.88%

Universal Waste Hazardous Waste 0.10%

0.02%

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

3

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{2. 2 1

0 2011 2012 2013 2014 2015 Figure 4-3 4-10 STP Nuclear Operating Company

2015 Environmental Report debris were also shipped for recycle in 2015. In addition, the station supports recycling programs for cardboard, paper, aluminum, printer cartridges and plastic. Approximately 89 tons of scrap metal, in addition to tin and steel recovered from building demolitions, were removed from the station for recycle in 2015. The station 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. Hazardous waste accounts for only a small portion of the waste generated at the South Texas Project; however, minimization and reduction of hazardous waste generation where feasible remains an important goal at the station .

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. Successful waste minimization and source reduction efforts by employees have allowed the South Texas Project to remain classified as a small-quantity generator since 2004. {Reference Figures 4-2 and 4-3}

CHEMICAL CONTROL AND MANAGEMENT The station's Integrated Spill Contingency Plan for the South Texas Project Electric Generating Station, 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 proposed 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 station 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 spills occurred in 2015.

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 2015 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 Corrective Action Program to document these conditions and track corrective actions to completion. Internal assessments, reviews and inspections are also used to document compliance .

STP Nuclear Operating Company 4-11

Nonradiological Environmental Operating Report This 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 2015.

Events that require reports 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 report at the time it is submitted to the cognizant agency. If a non routine 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 report was required in 2015.

Photo courtesy of Cheryl Bentley 4-12 STP Nuclear Operating Company

2015 Environmental Report Photo courtesy of Bill Sansing STP Nuclear Operating Company 4- 13

Photo courtesy of John Savage 4-14 STP Nuclear Operating Company

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 analyz ing 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 2015. Samples of fish and meat collected and analyzed show no plant-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 water molecule. Due to the design of the Main Cooling Reservoir, the presence of tritium in various Photo courtesy of' John Savage 5-2 STP Nuclear Operating Company

2015 Environmental Report sloughs and ditches onsite and the shallow aquifer is expected. Tritium has been detected in these types of samples and the concentrations remain 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 trending. Wells are sampled semi-annually, annually, and 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 2015 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 Aubrey Passafama STP Nuclear Operating Company 5-3

Photo courtesy of Jodie Jankauskas 5-4 STP Nuclear Operating Company

Radiological Environmental Operating Report PROGRAM DESCRIPTION The South Texas Project initiated a comprehensive preoperational Radiological Environmental Monitoring Program in July 1985. That program term inated 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 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 complaiment permanent, numbered sample stations.

6-2 STP Nuclear Operating Company

2015 Environmental Report RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM DESIGNATED SAMPLE LOCATION MAP Figure 6-1 STP Nuclear Operating Company 6-3

Radiological Environmental Operating Report RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ONSITE SAMPLE LOCATION MAP 27

300 271 258 I 259 27Q Figure 6-2 6-4 STP Nuclear Operating Company

2015 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 STP Nuclear Operating Company 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. Analytical values from offsite indicator sample stations continue to trend with the control stations. Measurements from onsite indicator samples continued to fluctuate within normal historical ranges.

{)~"""'""""'""""'""""'""""'""""'""""'""""'"""'*-*-*!!!!!!!!! Airborne Pathway Average quarterly air particulate sample beta activity from three onsite indicator stations and a single control station have been compared historically from 2001 through 2015 (see Figure 6-4). The average of the onsite indicators trends closely with the offsite control values. The comparison illustrates that plant operations are not having an impact on air particulate activity even at the Sensitive Indicator Stations (#1, #15, and #16). These stations are located near the site boundary downwind from the plant, based on the prevailing wind direction. The beta activity measured in the air particulate samples is from naturally occurring radioactive material.

Gamma 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- 2015 0.035 . . . - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - .

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2015 Environmental Report

-0~!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!............. 1!!!!!!!!!! Direct Exposure Pathway1!! ! ! ! ! ......... !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!IC.

Direct gamma radiation is monitored in the environment by thermoluminescent dosimeters (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 for three different types of stations. South Texas Project started using a vendor for offsite processing of the thermoluminescent dosimeters for environmental measurement of direct radiation during the third and fourth quarter of 2014.

The Control Stations, Stations #23 and #37, are greater than 10 miles from the site in the minimal wind direction. The prevailing wind direction was into the NNW 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 adding to the direct radiation in the offsite environment.

Environmental Dosimeter Comparisons

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Radiological Environmental Operating Report

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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 a depository of cobalt-60 still remains. Figure 6-6 shows the positive results from the plant-produced radioactive material cobalt-60 . 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 2015, cobalt-60 was identified in five out of six 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.

Cesium-137 was measured in six out of six bottom sediment samples from Stations #215 and

216 in the Main Cooling Reservoir. The highest measurement was 150 pCi/kg at Station

216. The highest measurement at Station #215 was 60 pCi/kg. Cesium-137 is often found in environmental media including soil and sediment from residual radioactive material from nuclear weapons testing. Soil and sediment samples taken in 1986 and 1987 prior to operation of STP 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 2015 were slightly higher than previously detected due to sampling non homogeneous media . In addition 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 monitored 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 2015. The amount of tritium measured in the Main Cooling Reservoir was consistent with the amount released. The amount of rainfall and river makeup influences the concentration of tritium in 6-8 STP Nuclear Operating Company

2015 Environmental Report Historical Comparison of Cobalt-GO in the Main Cooling Reservoir Sediment 2001- 2015 3SO

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

2. The initial time for calculating the remaining radioactivity is July 1 of the year released.

Figure 6-7 STP Nuclear Operating Company 6-9

Radiological Environmental Operating Report Historical Comparison of Tritium Added to and Remaining in the Main Cooling Reservoir 2001- 2015 3500 3000 2500 E

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Tritium Released to the Main Cooling Reservoir OTrit ium M easured in t he M ai n Cooling Reservoir Figure 6-8 Historical Comparison of Tritium Activity in Reservoir Relief Wells 2001- 2015 30000 30,000 picoCuries per Kilogram - Nuclear Regulatory Commision Reporting Level E

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Main Cool ing Rese rvoir Re li ef W ell (onsite} # 707 Figure 6-9 6-10 STP Nuclear Operating Company

2015 Environmental Report 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 2015, tritium levels remained consistent with historical values in the relief wells as shown in Figure 6-9.

Quarterly sampling of the Main Cooling Reservoir relief well #701 has been discontinued due to no water flow contributing to the inability to collect a sample 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 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 2015 sample from relief #707 well had indicated approximately 8,200 pCi/kg, which is less than required reporting levels.

The tritium concentrations in eight surface water sample points from 2001 through 2015 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 2015, six 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 2015 to determine if the tritium from the reservoir precipitated in the local area.

Tritium was not measured in any of the rainwater samples.

Photo courtesy of Sandy Dannhardt 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 2015, the concentration of tritium at Station #235 was consistent with values over the past three 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 2015 at 1,500 pCi/kg. In 2015 with a maximum value of onsite test wells at 5,900 pCi/ kg and remained below the United States Environmental Protection Agency drinking water limit {20,000 pCi/kg) .

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

STP Nuclear Operating Company 6-11

Radiological Environmental Operating Report Historical Comparison of Tritium Activity in Surface Water 2001- 2015 30,000 picoCuries per Kilogram - Nuclear Regulatory Comm ision Reporting Level 30000 20,000 picoCuries per Kilogram - Environm ental Protection Agency Reporting Leve l E

...ra

!>.I) 25000

.2

20000 E

J QI

.;::; c..

15000

~ "'

QI

J u 10000 0

u

c.. 5000 0

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 D River Sample Upstream of Plant (Offsite) #002 D River Sample Downstream of Plant (Offsite) #001 D West Branch of River (Onsite) #213 D little Robbins Slough (Onsite) #212

East Branch of Little Robbin s Slough (Onsite) #211

Ditch NE of Main Cooling Reservoir (Onsite) #229 D Main Cool ing Reservoir Slowdown (Onsite) #237 D M ain Cooling Reservoi r (Onsite) #216 Figure 6-10 Historical Comparison of Tritium Activity in Shallow Aquifer Ground Water 2001- 2015 30000 30,000 picoCuries per Kilogram - Nuclear Regulatory Comm ision Reporting Leve l E

ra

!>.I) 2SOOO -

.2 20,000 picoCuries per Kilogram - Environme ntal Protection Agency Reporting Level E

J QI 20000 -

.;::; c..

~ "'QI 15000 -

J u

0 u

c..

D Test Well B-3 directly south from MCR (on site) #235

Test Well B-4 Upper Aquifer (onsite) #251 Figure 6-11 6-12 STP Nuclear Operating Company

2015 Environmental Report Tritium Activity in Shallow Ground Water West of the Main Cooling Reservoir 2006- 2015 5000 E 4500

~ 4000 QI)

..9 3500

~

E Qj 3000

J

a. 2500

~ *;:: "'cu 2000

J u 1500 0

u 1000

§:

500 0

27 1 M onitoring We ll #MW-0805U * #258 Pi ezo meter Wel l #43 5-01

#2 70 M onitoring Well #MW-0805L D #259 Piezometer Well #435-02 Figure 6-12 A windmill-powered groundwater well, sample station #267, indicated tritium activity at 640 pCi/kg in 2015. This onsite ground water sample station is the most distant location from the Main Cooling Reservoir that tritium has been detected. This well is not used for human consumption .

The drinking water onsite is pumped from deep aquifer wells and is t ested monthly and composited quarterly to verify tritium is not present. The South Texas Project uses no water from the reservoir, shallow aquifers 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. This dose is insignificant compared to the approximately 620 millirem the public receives a year from natural radioactivity in the environment and the radiation received from medical procedures. 4 Other samples are collected and analyzed in addition to those required 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 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 within state and federal regulations and guidelines.

4 NCRP (2006) . Nationa l Council on Radiation Protection and Measurements, Ionizing Radiation Exposure of the Populatio n of the United States, (Bethesda , Maryland), NCRP Report No. 160.

STP Nuclear Operating Company 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 2015 results for wells that were sampled along with the historical highs measured prior to 2015 for each station since sampling began in 2006. Their locations are shown in Figure 6-14.

Sample Station 2015 Measurements Historical High (well) (pCi/kg) (pCi/kg) :

807 510 15300 808 400 2858 801 250 1152 844 920 920 809 590 424 824 less than 300 less than 300 835 less than 300 less than 300 842 less than 300 less than 300 843 less than 300 less than 300 838 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 2015. Station #809 tritium concentrations were related to the previously referenced pipe and subsequent repair. Station #844 tritium had a concentration of 800 pCi/kilogram and the source of that tritium is influenced by the Main Cooling Reservoir.

All the other wells sampled in 2015 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 2015 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 Main Cooling Reservoir. Information regarding the steam traps and subsequent response was 6-14 STP Nuclear Operating Company

2015 Environmental Report STP PROTECTED AREA GROUND WATER MONITORING WELLS N

~

W~ E s

06-02-2015 Figure 6-14 documented in the station's Corrective Action Program. 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 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 and completed in 2015.

In 2015, there were four non-significant instances where secondary water contacted the ground onsite. No discharge occurred offsite or to groundwater that may be used as a source of drinking water. The water was quickly recovered, recaptured, and clean up completed with no impact to groundwater.

STP Nuclear Operating Company 6-15

Radiological Environmental Operating Report LAND USE CENSUS The Annual Land Use Census is performed to determine if any changes have occurred in the location of residents and the use of the land within five miles of the South Texas Project generating units. The information is used to determine whether any changes are needed in the Radiological Environmental Monitoring Program. The census is performed by contacting area residents and local government agencies that provide the information. In addition, a survey is performed to verify the nearest residents within five miles of the South Texas Project generating units in each of 16 sectors. The results of the survey indicated no changes for 2015. The eleven sectors that have residents within five miles and the distance to the nearest residence in each sector are listed below.

SECTOR DISTANCE {MILES) LOCATION ENE 4.5 CR 232 (Ryman Rd.)

ESE 3.5 Selkirk Dr.

SE 3.5 Selkirk Dr.

SW 4.5 CR 386 (Corporon 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-Buckeye Road)

NW 4.5 CR 354 (Mondrik Road)

NNW 3.0 Runnells 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.

A commercial olive tree orchard was planted 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 t

sectors and at a control location in lieu of a garden census. The broad leaf vegetation samples collected also satisfy the collection requirement when milk samples are not available.

6-16 STP Nuclear Operating Company

2015 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 adequate and perform satisfactorily.

Quality audits and independent technical reviews help to determine areas that need attention.

These areas are addressed in accordance with the station's Corrective Action Program .

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. A total of approximately 11% of the analyses performed are quality control samples consisting of interlaboratory measurement assurance program samples, duplicate samples, and split 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 STP Nuclear Operating Company 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 2015 variances for Duplicates and Splits are shown in Figure 6-16.

Photo courtesy of Gary Parkey 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. During 2015 the following samples were not collected or were unacceptable for analysis:

One out of 176 direct radiation measurement samples was missed due to a damaged thermoluminescent dosimeter.

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

STP Nuclear Operating Company 6-17

Radiological Environmental Operating Report 2015 Radiological Laboratory Quality Assurance Program Performance 0-5% Difference 5-10% Difference 78 Total Analyses Figure 6-15 Duplicate & Split Agreement of Environmental Samples in 2015 Accceptable 96.8%

Air Alpha Variances 0.8%

- - -All Other Variances 2.4%

Figure 6-16 6-18 STP Nuclear Operating Company

2015 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 Quarterly Gamma dose Quarterly to 4 miles.

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

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

.!,- Control 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 because of the main cooling reservoir EXPOSURE: AIRBORNE .2 TOTAL SAMPLING STATIONS Sample Media, Number, Approximate Location, Minimum Routine Sampling Nominal Collection Analysis and Distance of Sample Stations from Analysis Mode Frequency Type Containment. Frequency.

Charcoal and Particulate Filters 1- Located at the exclusion zone, N, NNW, NW Continuous sampler 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 STP Nuclear Operating Company 6-19

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

EXPOSURE: WATERBORNE 13 TOTAL SAMPLING STATIONS Nominal Minimum Sample Media, Number And Approximate Location Routine Sampling Analysis Collection Analysis of Sample Stations Mode Type Frequency Frequency Surface 1- Located in MCR at the MCR blowdown Composite sample Monthly Gamma- Monthly structure. over a 1 month Isotopic period (grab if not 1- Located above the site on the Colorado River available) Tritium Quarterly not influenced by plant discharge (control). Composite 1- Located downstream from blow down entrance into the Colorado River.

Ground Grab Quarterly Gamma- Quarterly

~- Located in wells used to monitor tritium Isotopic &

migration in the shallow aquifer. Tritium Drinking Water 1- Located on site.

Grab Monthly Gross Beta & Monthly Gamma-1- Located at a control station. Isotopic Tritium Quarterly Composites Sediment Grab Semiannually Gamma- Semiannually Isotopic 1- Located above the site on the Colorado River, not influenced by plant discharge.

1- Located downstream from blowdown entrance into the Colorado River.

1- Located in MCR.

No municipal water systems are affected by STP. This sample taken from deep aquifer supplying drinking water to employees while at work.

MCR-STP Main Cooling Reservoir STP- South Texas Project 6-20 STP Nuclear Operating Company

2015 Environmental Report TABLE 1 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM (Continued)

EXPOSURE: INGESTION Z TOTAL SAMPLING STATIONS Nominal Minimum Sample Media, Number And Approximate Location Routine Sampling Analysis Collection Analysis of Sample Stations Mode Type Frequency Frequency Milk Grab Semi-monthly Gamma- Semi-monthly

when animals are Isotopic when animals are on pasture; And Low Level on pasture; monthly at other 1-131 monthly at other times. times.

Broad leaf Vegetation**

£- Located at the exclusion zone, N, NW, or Grab Monthly during Gamma- As collected NNW sectors. growing season Isotopic (When available) 1- Located in a minimal wind direction.

Fish and lrwertebrates (edible Qortions) 1- Representing commercially or recreational Grab Sample semi- Gamma- As collected important species in vicinity of STP that annually Isotopic on maybe influenced by plant operation. edible portions 1- Same or analogous species in area not influenced by STP.

Gammac 1- Same or analogous species in the MCR. Grab At time ofharvest Isotopic As collected Analysis in Agricultural Products edible portion

- - Gamma-Domestic Meat Grab Annually Isotopic As collected 1- Represents domestic stock fed on crops grown exclusively within 10 miles of the plant.

Limited source of sample in vicinity of the South Texas Project. (Attempts will be made to obtain samples when available.)

Three differeAt kinds of broadleaf vegetation are to be collected over the growing season, not each collection period.

- - No sample stations have been identified in the vicinity of the site. Presently no agricultural land is irrigated by water into which liquid plant wastes will be discharged. Agricultural products will be considered if these conditions change.

MCR"STP Main Cooling Reservoir STP- South Texas Project STP Nuclear Operating Company 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 - BOTTOM ANY COMBINATION OF BROAD LEAF F2 FISH - CRUSTACEAN & INSECT FEEDERS VB SAMPLES (Ll thru L7)

F3 FISH - PLANKIVORES & DETRITUS FEEDERS VP PASTURE GRASS Ll 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 STP Nuclear Operating Company.

2015 Environmental Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS (Continued)

STATION VECTOR MEDIA CODE LOCATION CODE (Approximate)

DR Al AP VB VP SO 1 lmile 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 Reservoir Makeup Pumping DRAI 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)

DRAI 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 023* 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 miles SSW MCR Dike DR 27 2.5 miles SW MCR Dike DR 28 5 miles WSW FM 1095 & Ellis Road (CR 380)

ORSO 29 4.5 miles W FM 1095 DR 30 6milesWNW 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.

DRAI 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 STP Nuclear Operating Company 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* lOmilesWSW (CR 323)

AEP Substation on SH 71 near Blessing (0.2 DR 38 10.5 miles 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 spillway DR 43 4.5 miles SE discharge channel Piezometer Well #446A. Alternate for WG WG 205 4.0 miles SE is Station Code 206 WG 206 4.0 miles SE Piezometer Well #446 ws 209 2 miles ESE Kelly Lake WD . 210 On Site Approved drinking water supply from STP WS Sl F(l, 2, or 3) 211+ 3.5 miles S East Branch Little Robbins Slough WS Sl F(l, 2, or 3) 212+ 4 miles S Little Robbins 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 Colorado 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)

Colorado 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 ofSTP. Alternate for WS or S(l or 2) is station 233

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

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

Station codes typed in bold identify offsite locations.

Control Station 6-24 STP Nuclear Operating Company

2015 Environmental Report TABLE 2 SAMPLE MEDIA AND LOCATION DESCRIPTIONS (Continued)

STATION VECTOR MEDIA CODE LOCATION CODE (Approximate)

WD 228* 14 miles NNE Le Tulle 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 <1 miles MCR circulating water intake S(l or 2) WS 242* >10 miles N Colorado 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 (windmill) located on private WG 245 4.5 mile SSE property approx. 1 mile south of the MCR Drainage ditch originating at protected area WSSl 246 <1 mile N fence north of Unit 2 ws 247 <1 mile E Essential Cooling Pond Point in drainage ditch north of protected WSSl 248 <1 mile N area downstream of Unit #1 Protected Area storm drain discharge Control sample 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 shallow aquifer 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' inside east of site boundary fence Piezometer Well #435-01, 1.5 miles 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' east 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 satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

Control Station STP Nuclear Operating Company 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 Piezometer Well #447 104' deep WG 264 3.2 miles ESE Piezometer Well #447 A 46' deep WG 266 0.7 miles NW Piezometer Well #602A 40' deep WG 267 2.7 miles ESE Windmill north of Heavy Haul Road WG 268 3.0 miles SE Windmill east of MCR Windmill south of STP owner controlled WG 269 4.2 miles SSE area on private land Monitor well MW-805L 49' deep. Across WG 270 2.9 miles SW Rd from station # 258 & 259 Monitor well MW-805U Across Rd from WG 271 2.9 miles 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 Reservoir STP- South Texas Project Media codes typed in bold satisfy collection requirement described in Table 1.

Station codes typed in bold identify offsite locations.

Control Station 6-26 STP Nuclear Operating Cornpany

2015 Environmental Report 2015 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 nonroutine 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 measurements 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 2015 by 15 direct radiation measurements, five additional surface water samples, one additional drinking water, eight additional pasture grass, 24 additional groundwater samples, four additional rain water samples, four additional relief well water sample and four additional sediment samples. Fish and crustacean samples vary in number according to availability but also exceeded the minimum number required by Table 1. Also, 260 additional air sample stations were collected from five weekly air sample stations and 28 additional surface 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.

STP Nuclear Operating Company 6-27

Radiological Environmental Operating Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium : Direct Radiation Units: Mill iRoentgen/Stand ard Quarter ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE / NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Ga mma 175f 0 5.0E+OO 1.3E+Ol ( 163f 163) 1.5 mi les W l.7E+Ol ( 8 f 8) l.3E+Ol ( 12 f 12)

( 9.0E+OO - 2.SE+Ol ) (#013) (1.5E+Ol - l.8E+Ol) ( 1.lE+Ol - l.6E+Ol )

t Number of pos1t1ve measurements f total measu rements at spec1f1ed locations.

TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Ai rborn e Particu lat e & Radioiodine Units: PicoCuri es per cubi c met er ANA LYSIS TOTAL ANALYSES LOWER IN DICATOR LOCATI ONS LOCATION WITH HIGHEST AN NU AL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATI ON M EAN t M EAN t MEASUREM ENTS DETECTION RANGE INFORMATION RA NGE RANGE Gross Bet a 260f O 1.4E-03 l.9E-02 ( 208 f 208 ) 1 mile N 1.9E-02 ( 52 f 52 ) 1.9E-02 ( 52 f 52 )

( 7.lE 4.3E-02 ) (#001) ( 8.6E 4.3E-02 ) ( 8.9 E 4.3E-02 )

lodine-13 1 260f O l.2E-02 --- ( of 208 l --- --- --- ( of 52 l Cesium-134 20f O 4.4E-04 --- ( of 16 l --- --- --- ( Of 4)

Cesium-137 20f O 4.lE-04 --- ( o I 16 l --- --- --- ( Of 4)

Manganese-54 20f O 4.9E-04 --- ( of 16 l --- --- --- ( Of 4) lron-59 20f O 2.lE-03 --- ( of 16 l --- --- --- ( Of 4)

Cobalt-58 20f 0 6.9E-04 --- ( of 16 l --- --- --- ( Of 4)

Coba lt-60 20f O 4.8E-04 --- ( Of 16) --- --- --- ( Of 4)

Zinc-65 20f O 1.3E-03 --- ( of 16 l --- --- --- ( of 4 l Zirconium-95 20f O 1.3E-03 --- ( of 16 l --- --- --- ( 0/ 4)

Niobium-95 20/ 0 7.SE-04 --- ( of 16 l --- --- --- ( Of 4)

Lanthanu m-140 20f O 7.0E-03 --- ( of 16 l --- --- --- ( Of 4)

Ba ri um-140 t Num ber of positi ve measure ments f total measurements at specified loca ti ons.

Photo courtesy of Robyn Savage 6-28 STP Nuclear Operating Company

2015 Environmental Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Surface Water Units: PicoCuries per Kilogram 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 RANGE INWRMATION RANGE RANGE Hydrogen-3 12f0 2.7E+02 9.2E+03 ( 4 f 8 ) 3 miles SSE 9.2E+03 ( 4 f 4 ) --- ( Of 4)

( 8.8E+03 - 9.8E+03 ) (#216) ( 8.8E+03 - 9.8E+03 )

lodine-131 41f 0 4.8E+OO --- ( Of 27) --- --- --- ( Of 14)

Cesium-134 41f O 1.8E+OO --- ( Of 27) --- --- --- ( Of 14)

Cesium-137 41f0 2.0E+OO --- ( Of 27) --- --- --- ( Of 14)

Manganese-54 41f O 2.1E+OO --- ( Of 27) --- --- --- ( Of 14) lron-59 41f O 4.8E+OO --- ( Of 27) --- --- --- ( Of 14)

Cobalt-58 41f 0 2.2E+OO --- ( Of 27) --- --- --- ( 0/ 14)

Cobalt-60 41/0 2.lE+OO --- ( 0/ 27) --- --- --- ( 0/ 14)

Zinc-65 41/0 4.5E+OO --- ( 0/ 27) --- --- --- ( Of 14)

Zirconium-95 41f0 3.7E+OO --- ( 0/ 27) --- --- --- ( 0/ 14)

Niobium-95 41f0 2.2E+OO --- ( 0/ 27) --- --- --- ( 0/ 14)

Lanthanum-140 41/0 4.9E+OO --- ( 0/ 27) --- --- --- ( 0/ 14)

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

TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Ground Water {On site test well) Units: PicoCuries per Kilogram ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION' MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Hydrogen-3 22/0 2.7E+02 4.2E+03 ( 14 f 22 ) 4.0 miles SSE 4.9E+03( 5f 5) no samples

( 3.0E+03 - 5.9E+03 ) (#251) ( 3.0E+03 - 5.9E+03 )

lodine-131 22f0 2.9E+OO --- ( Of 22) --- --- no samples Cesium-134 22/0 2.6E+OO --- ( 0/ 22) --- --- no samples Cesium-137 22/0 2.8E+OO --- ( 0/ 22) --- --- no samples Manganese-54 22f0 2.7E+OO --- ( 0/ 22) --- --- no samples lron-59 22/0 5.5E+OO --- ( Of 22) --- --- no samples Cobalt-58 22/ 0 2.7E+OO --- ( 0/ 22) --- --- no samples Cobalt-60 22f0 2.9E+OO --- ( 0/ 22) --- --- no samples Zinc-65 22/0 7.9E+OO --- ( 0/ 22) --- --- no samples Zirconium-95 22/0 4.4E+OO --- ( Of 22) --- --- no samples Niobium-95 22/0 3.0E+OO --- ( 0/ 22) --- --- no samples La ntha nu m-140 22/0 4.0E+OO --- ( Of 22) --- --- no samples Barium-140 t Number of positive measurements I total measurements at specified locations.

STP Nuclear Operating Company 6-29

Radiological Environmental Operating Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Drinking Water Units: PicoCuries per Kilogram ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Gross Beta 25f0 1.0E+OO 2.lE+OO ( 13 f 13 ) 14 miles NNE 6.8E+OO ( 12 f 12 ) 6.8E+OO ( 12 f 12 )

( 1.2E+OO - 3.6E+OO ) (#228) ( 1.9E+OO - 1.2E+01 ') ( 1.9E+OO - 1.2E+Ol )

Hydrogen-3 8f O 2.7E+02 --- ( Of 4) --- --- --- ( Of 4) lodine-131 25f O 3.2E+OO --- ( Of 13) --- --- --- ( Of 12)

Cesium-134 25f O 2.6E+OO --- ( Of 13) --- --- --- ( Of 12)

Cesium-137 25f O 2.8E+OO --- ( Of 13) --- --- --- ( Of 12)

Manganese-54 25f0 2.7E+OO --- ( Of 13) --- --- --- ( Of 12) lron-59 25f0 5.6E+OO --- ( Of 13) --- --- --- ( Of 12)

Cobalt-58 25f 0 2.6E+OO --- ( Of 13) --- --- --- ( Of 12)

Cobalt-60 25f O 2.9E+OO --- ( Of 13) --- --- --- ( Of 12)

Zinc-65 25f O 7.3E+OO --- ( Of 13) --- --- --- ( Of 12)

Zirconium-95 25f0 4.5E+OO --- ( Of 13) --- --- --- ( Of 12)

Niobium-95 25f0 2.9E+OO --- ( of 13) --- --- --- ( Of 12)

Lanthanum-140 25f O 4.0E+OO --- ( of 13) --- --- --- ( Of 12)

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

TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Rain Water Units: PicoCuries per Kilogram ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS, LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Hydrogen-3 4f0 2.7E+02 --- ( Of 4) --- --- no samples lodine-131 4f O 3.9E+OO --- ( Of 4) -- --- no samples Cesium-134 4f O 2.6E+OO --- ( Of 4) --- --- no samples Cesium-137 4f0 2.7E+OO --- ( Of 4) --- --- no samples Manganese-54 4f0 2.9E+OO --- ( Of 4) --- --- no samples lron-59 4f0 5.8E+OO --- ( Of 4) --- --- no samples Cobalt-58 4f0 2.8E+OO --- ( Of 4) --- --- no samples Cobalt-60 4f O 2.8E+OO --- ( Of 4) --- --- no samples Zinc-65 4f0 5.9E+OO --- ( Of 4) --- -- no samples Zirconium-95 4f0 4.9E+OO --- ( Of 4) --- --- no samples Niobium-95 4f O 2.9E+OO --- ( Of 4) --- --- no samples Lanthanum-140 4f0 4.3E+OO --- ( Of 4) --- --- no samples Barium-140 t Number of pos1t1ve measurements f total measurements at spec1f1ed locations .

6-30 STP Nuclear Operating Company

2015 *Environmental Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Sediment-Shoreline Units: PicoCuries per Kilogram dry weight 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 RANGE INFORMATION RANGE RANGE Cesium-134 4f0 1.8E+Ol --- ( Of 2) --- --- --- ( Of 2)

Cesium-137 4f O 2.lE+Ol 2.lE+Ol ( l f 2) 6 miles SE 2.lE+Ol ( l f 2) --- ( Of 2)

( 2.lE+Ol - 2.lE+Ol) (#227) ( 2.lE+Ol - 2.lE+Ol)

Manganese-54 4f O 2.3E+Ol --- ( Of 2) --- --- --- ( Of 2) lron-59 4f O 6.4E+Ol --- ( Of 2) --- --- --- ( Of 2)

Cobalt-58 4f O 2.SE+Ol --- ( Of 2) --- --- --- ( Of 2)

Cobalt-60 4f O 2.3E+Ol --- ( Of 2) --- --- --- ( Of 2)

Zinc-65 4f0 6.2E+Ol --- ( Of 2) --- --- --- ( Of 2)

Zirconium-95 4f O 4.7E+Ol --- ( Of 2) --- --- --- ( Of 2)

Niobium-95 4f O 3.0E+Ol --- ( Of 2) --- --- --- ( Of 2)

Lanthanum-140 4f O 1.1E+02 --- ( Of 2) --- -- --- ( Of 2)

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

TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Sediment-Bottom Units: PicoCuries per Kilogram dry weight 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 RANGE INFORMATION RANGE RANGE Cesium-134 6f O 2.8E+Ol --- ( Of 6) --- --- no samples Cesium-137 6f O 2.lE+Ol 8.8E+Ol ( 6f 6) 3 miles SSE 1.1E+02 ( 4f 4) no samples

( 3.2E+Ol - 1.5E+02 ) (#216) ( 8.2E+Ol - 1.5E+02 )

Manganese-54 6f O 3.3E+Ol --- ( Of 6) --- -- no samples lron-59 6f O 1.0E+02 --- ( Of 6) --- --- no samples Cobalt-58 6f0 3.6E+Ol --- ( Of 6) --- --- no samples Cobalt-60 6f O 3.0E+Ol 7.6E+Ol ( 5 f 6) lmileSW 8.2E+Ol ( l f 2) no samples

( 6.0E+Ol - 8.4E+Ol ) (#215) ( 8.2E+Ol - 8.2E+Ol )

Zinc-65 6f O 9.9E+Ol --- ( Of 6) --- --- no samples Zirconium-95 6f0 6.9E+Ol --- ( Of 6) --- --- no samples Niobium-95 6f0 4.3E+Ol --- ( Of 6) --- --- no samples Lanthanum-140 6f0 2.1E+02 --- ( Of 6) --- --- no samples Barium-140 t Number of pos1t1ve measurements f total measurements at spec1f1ed locations .

STP Nuclear Operating Company 6-31

Radiological Environmental Operating Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Banana Leaves Units: PicoCuries per Kilogram wet weight 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 RANGE INFORMATION RANGE RANGE lodine-131 16f O 1.8E+01 --- ( 0/ 11) --- --- --- ( 0/ 5)

Cesium-134 16f0 1.1E+01 --- ( 0/ 11) --- --- --- ( 0/ 5)

Cesium-137 16f O 1.2E+01 --- ( oI 11 l --- --- --- ( 0/ 5)

Manganese-54 16/0 1.2E+01 --- ( 0/ 11) --- --- --- ( 0/ 5) lron-59 16f O 3.0E+Ol --- ( 0/ 11) --- --- --- ( 0/ 5)

Cobalt-58 16/0 1.2E+01 --- ( Of 11) --- --- --- ( 0/ 5)

Cobalt-60 16/0 1.4E+01 --- ( 0/ 11) --- --- --- ( Of 5)

Zinc-65 16/ 0 3.6E+01 --- ( 0/ 11) --- --- --- ( 0/ 5)

Zirconium-95 16/ 0 2.0E+Ol --- ( Of 11) --- --- --- ( 0/ 5)

Niobium-95 16/0 1.2E+01 --- ( 0/ 11) --- --- --- ( 0/ 5)

Lanthanum-140 16/0 1.7E+01 --- ( Of 11) --- --- --- ( Of 5)

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

TABLE. 3 201S RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Cana Leaves Units: PicoCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE lodine-131 15f O 1.3E+01 --- ( Of 10) --- --- --- ( 0/ 5)

Cesium-134 15f O 1.2E+01 --- ( Of 10) --- --- --- ( o I 5 l Cesium-137 15f O 1.3E+01 --- ( Of 10) --- --- --- ( oI 5 l Manganese-54 15f 0 1.3E+01 --- ( 0/ 10) --- --- --- ( Of 5) lron-59 15f O 3.2E+01 --- ( 0/ 10) --- --- --- ( 0/ 5)

Cobalt-58 15/ 0 1.3E+01 --- ( 0/ 10) --- --- --- ( 0/ 5)

C:obalt-60 15f O 1.6E+01 --- ( 0/ 10) --- --- --- ( 0/ 5)

Zinc-65 15/0 3.9E+01 --- ( 0/ 10) --- --- -~- ( oI 5 l Zirconium-95 15f O 2.2E+01 --- ( Of 10) --- --- --- ( 0/ 5)

Niobium-95 15/ 0 1.3E+01 --- ( 0/ 10) --- --- --- ( 0/ 5)

Lanthanum-140 15/ 0 1.5E+01 --- ( 0/ 10) --- --- --- ( 0/ 5)

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

6-32 STP Nuclear Operating Company

2015 Environmental Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Mustard Greens Units: PicoCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER 'INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL LOCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE lodine-131 7f O 1.lE+Ol --- ( Of 4) --- --- --- ( Of 3)

Cesium-134 7f O 1.0E+Ol --- ( Of 4) --- --- --- ( Of 3)

Cesium-137 7f O 1.1E+01 --- ( Of 4) --- --- --- ( Of 3)

Manganese-54 7f D 1.2E+Ol --- ( Of 4) --- --- --- ( Of 3) lron-59 7f O 2.6E+Dl --- ( Of 4) --- --- --- ( Of 3)

Cobalt-58 7f O 1.lE+Ol --- ( Of 4) --- --- --- ( Of 3)

Cobalt-60 7f0 1.3E+Ol --- ( Of 4) --- --- --- ( Of 3) ;

Zinc-65 7f 0 3.lE+Ol --- ( Of 4) --- --- --- ( Of 3)

Zirconium-95 7f O 1.9E+Ol --- ( Of 4) --- --- --- ( Of 3)

Niobium-95 7f O 1.2E+01 --- ( Of 4) --- --- --- (. Of 3)

Lanthanum-140 7f O 1.3E+Ol --- ( Of 4) --- --- --- ( Of 3)

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

TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Fish - Piscivorous Units: PicoCuries per Kilogram wet weight 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 RANGE INFORMATION RANGE RANGE Cesium-134 6f0 3.0E+Ol --- ( Of 6) --- --- no samples Cesium-137 6f0 3.lE+Ol --- ( Of 6) --- --- no samples Manganese-54 6f0 3.3E+Ol --- ( Of 6) --- --- no samples lron-59 6f0 9.2E+Ol --- ( Of 6) --- --- no samples Cobalt-58 6f0 3.SE+Ol --- ( Of 6) --- --- no samples Cobalt-60 6f0 3.5E+Ol --- ( Of 6) --- --- no samples Zinc-65 6f0 8.0E+Ol --- ( Of 6) --- --- no samples Zirconium-95 6f O 6.4E+Ol --- ( Of 6) --- --- no samples Niobium-95 6f O 3.6E+Ol --- ( Of 6) --- --- no samples Lanthanum-140 6f O 1.7E+02 --- ( Of 6) --- --- no samples Barium-140 t Number of positive measurements f total measurements at specified locations.

STP Nuclear Operating Company 6-33

Radiological Environmental Operating Report TABLE 3 2014 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Fish - Crustacean & Insect Feeders Units: PicoCuries per Kilogram wet weight ANALYSIS TOTAL ANALYSES LOWER INDICATOR LOCATIONS LOCATION WITH HIGHEST ANNUAL MEAN CONTROL toCATIONS TYPE /NON ROUTINE LIMITOF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 4/0 3.lE+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Cesium-137 4/0 3.2E+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Manganese-54 4/0 3.6E+Ol --- ( 0/ 2) --- J

--- --- ( 0/ 2) lron-59 4/0 8.lE+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Cobalt-58 4/0 3.6E+01 --- ( 0/ 2) --- --- --- ( 0/ 2)

Cobalt-60 4/0 3.7E+01 --- ( 0/ 2) --- --- --- ( 0/ 2)

Zinc-65 4/0 8.lE+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Zirconium-95 4/0 6.lE+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

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

Lanthanum-140" 4/0 1.3E+02 --- ( 0/ 2) ---, --- --- ( oI 2l Barium-140 t Number of pos1t1ve measurements/ total measurements at spec1f1ed locations .

TABLE 3 2015 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 /NON ROUTINE LIMIT OF MEAN t LOCATION MEAN t MEAN t MEASUREMENTS DETECTION RANGE INFORMATION RANGE RANGE Cesium-134 4/0 3.3E+Ol --- ( oI 2 l --- --- --- ( oI 2J Cesium-137 4/0 3.2E+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Manganese-54 4/0 3.6E+01 --- ( 0/ 2) --- --- --- ( 0/ 2) lron-59 4/0 8.2E+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Cobalt-58 4/0 3.8E+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Cobalt-60 4/0 3.6E+Ol --- ( 0/ 2) --- --- --- ( 0/ 2)

Zinc-65 4/0 7.8E+01 --- ( 0/ 2) --- --- --- ( oI 2 l Zirconium-95 4/0 6.3E+01 --- ( 0/ 2) --- --- --- ( 0/ 2)

Niobium-95 4/0 3.8E+01 --- ( 0/ 2) --- --- --- ( 0/ 2)

Lanthanum-140 4/0 1.3E+02 --- ( 0/ 2) --- --- --- ( 0/ 2)

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

6-34 STP Nuclear Operating Company

2015 Environmental Report TABLE 3 2015 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM ANALYSIS

SUMMARY

Medium: Beef Meat 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 Cesiu m -134 2/ 0 3.lE+Ol --- ( 0/ 2 ) --- --- n o samp les Ces iu m-137 2f 0 3.0E+Ol --- ( Of 2) --- --- n o samples Manganese-54 2f O 3.l E+Ol --- ( Of 2) --- --- no sa m ples lron-59 2f 0 9.4E+Ol --- ( Of 2) --- --- no sa mples Cobalt-58 2f O 3.8E+Ol --- ( Of 2) --- --- no sa mples Cobalt-60 2f O 3.3E+Ol --- ( Of 2) --- --- no sa mples Zinc-65 2f 0 8.0E+Ol --- ( Of 2) --- --- no sa mples Zirco nium-95 2f 0 7.0E+Ol --- ( Of 2) --- --- no samples Niobium-9 5 2f O 4.3E+Ol --- ( Of 2) --- --- no sa mples Lanthanum-140 2f O 2.0E+02 --- ( Of 2) --- --- no samples Barium-140 t Number of positive measurements f total measurements at spec ified locations.

Photo courtesy of' Rodger Harris STP Nuclear Operating Company 6-35

6-36 STP Nuclear Operating Company STP Nuclear Operating Company