South Texas Nuclear Generating Station

South Texas Nuclear Project (STNP) Electric Generating Station
Location of South Texas Nuclear Project (STNP) Electric Generating Station in Texas
Country United States
Location Matagorda County, near Bay City, Texas
Coordinates 28°47′44″N 96°2′56″W / 28.79556°N 96.04889°W / 28.79556; -96.04889Coordinates: 28°47′44″N 96°2′56″W / 28.79556°N 96.04889°W / 28.79556; -96.04889
Status Operational
Construction began 1975–89
Commission date Unit 1: August 25, 1988
Unit 2: June 19, 1989
Construction cost $5.5 billion
Owner(s) NRG Energy 44%
City of San Antonio 40%
City of Austin 16%
Operator(s) STP Nuclear Operating Company (STPNOC)
Nuclear power station
Reactor type Pressurized water reactor
Reactor supplier Westinghouse
Cooling source Colorado River
Cooling towers no
Power generation
Units operational 2 × 1,380 MW
Nameplate capacity 2,760 MW
Capacity factor 91.7%
Average generation 22,179 GWh

The South Texas Nuclear Project Electric Generating Station (also known as STNP, STPEGS, South Texas Nuclear Project), is a nuclear power station southwest of Bay City, Texas, United States. The STNP occupies a 12,200-acre (4,900 ha) site on the Colorado River about 90 miles (140 km) southwest of Houston. It consists of two Westinghouse Pressurized Water Reactors and is cooled by a 7,000-acre (2,800 ha) reservoir, which eliminates the need for cooling towers. Only recently the capacity of Palo Verde Nuclear Generating Station surpassed these Texas units.[1]


On December 6, 1971, Houston Lighting & Power Co. (HL&P), the City of Austin, the City of San Antonio, and the Central Power and Light Co. (CPL) initiated a feasibility study of constructing a jointly-owned nuclear plant. The initial cost estimate for the plant was $974 million (equivalent to approximately $5,700,741,167 in 2015 United States Dollars[2]).

By mid-1973, HL&P and CPL had chosen Bay City as the site for the project and San Antonio had signed on as a partner in the project. Brown and Root was selected as the architect and construction company. On November 17, 1973 voters in Austin narrowly approved their city's participation[3] and the city signed onto the project on December 1. Austin held several more referendums through the years on whether to stay in the project or not.[4][5][6]

An application for plant construction permits was submitted to the Atomic Energy Commission (now the Nuclear Regulatory Commission (NRC)) in May 1974 and the NRC issued the permits on December 22, 1975. Construction started at December 22, 1975.[7]

By 1978, the South Texas Project was two years behind schedule and had substantial cost overruns. A new management team had been put in place by HL&P in late 1978 to deal with the cost overruns, schedule delays and other challenges. However, events at Three Mile Island in March 1979 had a substantial impact on the nuclear industry including STNP. The new team again moved forward with developing a new budget and schedule. Brown and Root revised their completion schedule to June, 1989 and the cost estimate to $4.4–$4.8 billion. HL&P executives consulted with its own project manager and concluded that Brown and Root was not making satisfactory progress and a decision was reached to terminate their role as architect/engineer but retain them as constructor. Brown and Root was relieved as architect/engineer in September 1981 and Bechtel Corporation contracted to replace them. Less than two months later, Brown and Root withdrew as the construction contractor and Ebasco Constructors was hired to replace them in February 1982 as constructor. With the new management team of HL&P, Bechtel, and Ebasco in place they overcame incredible regulatory and political obstacles to set the project on a path to successful completion.

Austin voters authorized the City Council on November 3, 1981 to sell the city's 16 percent interest in the STP.[8] No buyers were found.

Unit 1 reached initial criticality on March 8, 1988 and went into commercial operation on August 25. Unit 2 reached initial criticality on March 12, 1989 and went into commercial operation on June 19.

In February 1993, both units had to be taken offline to resolve problems with the steam-driven auxiliary feedwater pumps. They were not back in service until March (Unit 1) and May (Unit 2) of 1994. The history of STNP is somewhat unique when most nuclear plants that were in the early stages of engineering construction at the time of the Three Mile Island event were never completed. STNP operating team has been noted highly for its stellar operating history which must also be based upon a solid design and construction plan.

Whistleblowing case

Nuclear whistleblower Ronald J. Goldstein was a supervisor employed by EBASCO, which was a major contractor for the construction of the South Texas plants. In the summer of 1985, Goldstein identified safety problems to SAFETEAM, an internal compliance program established by EBASCO and Houston Lighting, including noncompliance with safety procedures, the failure to issue safety compliance reports, and quality control violations affecting the safety of the plant.

SAFETEAM was promoted as an independent safe haven for employees to voice their safety concerns. The two companies did not inform their employees that they did not believe complaints reported to SAFETEAM had any legal protection. After he filed his report to SAFETEAM, Goldstein was fired. Subsequently, Goldstein filed suit under federal nuclear whistleblower statutes.

The U.S. Department of Labor ruled that his submissions to SAFETEAM were protected and his dismissal was invalid, a finding upheld by Labor Secretary Lynn Martin. The ruling was appealed and overturned by the Fifth Circuit Court of Appeals, which ruled that private programs offered no protection to whistleblowers. After Goldstein lost his case, Congress amended the federal nuclear whistleblower law to provide protection for reports made to internal systems and prevent retaliation against whistleblowers.[9]


The STPEGS reactors are operated by the STP Nuclear Operating Company (STPNOC). Ownership is divided among NRG Energy at 44 percent, San Antonio municipal utility CPS Energy at 40 percent and Austin Energy at 16 percent.[10]

Surrounding population

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.[11]

The 2010 U.S. population within 10 miles (16 km) of South Texas Project was 5,651, a decrease of 2.4 percent in a decade, according to an analysis of U.S. Census data for The 2010 U.S. population within 50 miles (80 km) was 254,049, an increase of 10.2 percent since 2000. Cities within 50 miles include Lake Jackson (40 miles to city center) and Bay City.[12]

Recent developments

On June 19, 2006, NRG Energy filed a Letter Of Intent with the Nuclear Regulatory Commission to build two 1,358-MWe Advanced Boiling Water Reactors (ABWRs) at the South Texas Nuclear Project site.[13] South Texas Nuclear Project Partners CPS Energy and Austin Energy were not involved in the initial Letter of Intent and development plans.

On September 24, 2007, NRG Energy filed a full application with the NRC to build two Toshiba ABWRs at the South Texas Nuclear Project site.[13] This was the first full application to be submitted to the NRC since 1979. This proposed expansion of the South Texas Project would generate an additional 2700 MW of electrical generating capacity, which would ultimately double the capacity of the current site.[14] The total estimated cost of constructing the two reactors is $10 billion, or $13 billion with financing, according to Steve Bartley, interim general manager at CPS Energy

In October 2009 main contractor, Toshiba, had informed CPS Energy that the cost would be "substantially greater," possibly up to $4 billion more. As a result of the escalating cost estimates for units 3 and 4,[15] in 2010 CPS Energy reached an agreement with NRG Energy to reduce CPS's stake in the new units from 50% to 7.625%. To that point, CPS Energy had invested $370 Million in the expanded plant. CPS Energy's withdrawal from the project put the expansion into jeopardy.

In October 2010, the South Texas Project announced that the Tokyo Electric Power Company, or TEPCO, had entered into an agreement with Nuclear Innovation North America (a joint venture between the reactor manufacturer, Toshiba, and plant partner NRG Energy) which was the largest of the two stakeholders in the proposed reactors, to purchase an initial 9.2375% stake in the expansion for $125 Million, and $30 Million for an option to purchase an additional stake in the new units for $125 Million more (resulting in approximately 18% ownership by TEPCO, or 500MW of generation capacity). The agreement was made conditional upon STNP securing construction loan guarantees from the United States Department of Energy.[16][17][18]

On 19 April 2011 in a conference call with shareholders, NRG announced they had decided to abandon the permitting process on the two new units in Texas. NRG attributed the cancellation to the ongoing expense of planning the reactor, combined with slow permitting process. Anti-nuclear campaigners alleged that the financial situation of new partner TEPCO, combined with the ongoing Fukushima nuclear accident were also key factors in the decision.[19] NRG has written off its investment of $331 million in the project.[20]

Despite the announcement of the reactor's cancellation by NRG Energy in the Spring of 2011, the Nuclear Regulatory Commission continued the COL process for the new reactors in October 2011.[21] It was not clear at the time why the reactor license application was proceeding. Some pre-construction activities were performed on site during early 2015 and initial NRC documents list the original targeted commercial operational dates as March 2015 for unit 3 and a year later for the other unit.[22] The COL was approved by the NRC on February 9, 2016.[23] Due to market conditions, no construction events were occurring at the time of COL approval. These two planned units may never be built and do not have a planned construction date.[24]

Seismic risk

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at South Texas was 1 in 158,730, according to an NRC study published in August 2010.[25][26]

Reactor data

The South Texas Generating Station consists of two operational reactors, two additional are planned.

Reactor unit[27] Reactor type Capacity Construction started Electricity grid connection Commercial operation Current License Expiration
Net Gross
South Texas-1 Westinghouse 4-loop 1280 MW 1354 MW 22 December 1975 30 March 1988 25 August 1988 20 August 2027 (extension pending)
South Texas-2 Westinghouse 4-loop 1280 MW 1354 MW 22 December 1975 11 April 1989 19 June 1989 15 December 2028 (extension pending)
South Texas-3 (planned)[28] ABWR 1350 MW 0 MW License Issued (2016)[29]
South Texas-4 (planned)[30] ABWR 1350 MW 0 MW License Issued (2016)[29]

See also


  1. State of Texas. Public Utility Commission of Texas. Railroad Commission of Texas. (November 2012). "Public Utility Commission Section-New Energy Resources" Texas Energy Assurance Plan. Retrieved February 23, 2015.
  2. Federal Reserve Bank of Minneapolis Community Development Project. "Consumer Price Index (estimate) 1800–". Federal Reserve Bank of Minneapolis. Retrieved October 21, 2016.
  3. "General Municipal Election: November 17, 1973" City of Austin
  4. "General Municipal Election: August 14, 1976" City of Austin
  5. "General Municipal Election: January 20, 1979" City of Austin
  6. "General Municipal Election: April 7, 1979" City of Austin
  7. Power Reactor Information System of the IAEA: South Texas
  8. "General Municipal Election: November 3, 1981" City of Austin
  9. Kohn, Stephen Martin (2011). The Whistleblower's Handbook: A Step-by-Step Guide to Doing What's Right and Protecting Yourself. Guilford, CT: Globe Pequot Press. pp. 116–18. ISBN 9780762774791.
  10. "About Us" South Texas Project Nucler Operating Company
  12. Bill Dedman, Nuclear neighbors: Population rises near US reactors,, April 14, 2011 Accessed May 1, 2011.
  13. 1 2 "EPC Next Step In CPS Energy's Evaluation of Nuclear Option" CPS Energy
  14. "NRG Files First Full Application for U.S. Reactor"
  15. "$6.1 million spent to end nuclear deal" Express News CPS Energy STNP Expansion Termination Article
  16. "TEPCO Partners in STP Expansion" STP Press Release
  17. "CPS Energy sees need for new STP units". World Nuclear News. June 30, 2009. Retrieved 2009-06-28.
  18. "Nuclear cost estimate rises by as much as $4 billion". October 28, 2009. Retrieved 2009-10-28.
  19. "NRG ends project to build new nuclear reactors". The Dallas Morning New. April 19, 2011. Retrieved 2015-03-14.
  20. Matthew L. Wald (April 19, 2011). "NRG Abandons Project for 2 Reactors in Texas". New York Times.
  21. "Licensing Board to Conduct Hearing Oct. 31 in Rockville, Md., on South Texas Nuclear Project New Nuclear Reactor Application" (PDF). US NRC Press Releases. US Federal Government. Retrieved 13 October 2011.
  22. United States Nuclear Regulatory Commission. (October 29, 2013). "STP 3 & 4 Environmental Report- Proposed Dates for Major Activities". South Texas Project Units 3 & 4 COLA (Environmental Report), Rev. 10. Retrieved February 23, 2015.
  25. Bill Dedman, "What are the odds? US nuke plants ranked by quake risk,", March 17, 2011 Accessed April 19, 2011.
  27. Power Reactor Information System of the IAEA: „United States of America: Nuclear Power Reactors- Alphabetic“
  28. Power Reactor Information System of the IAEA: „Nuclear Power Reactor Details - SOUTH TEXAS-3“
  29. 1 2 [ Issued Combined Licenses for South Texas Project, Units 3 and 4 by the NRC
  30. Power Reactor Information System of the IAEA: „Nuclear Power Reactor Details - SOUTH TEXAS-4“


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