South Texas Nuclear Generating Station
|South Texas Project Electric Generating Station|
|Location||Matagorda County, near Bay City, Texas|
|Commission date||Unit 1: August 25, 1988
Unit 2: June 19, 1989
|Licence expiration||Unit 1: August 20, 2027
Unit 2: December 15, 2028
|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)|
|Architect(s)||Start: Brown & Root
Finish: Bechtel Corp.
|Constructor(s)||Start: Brown & Root
Finish: Ebasco Const., Inc.
|Reactors operational||2 x 1250 MW|
|Reactors planned||2 x 1358 MW|
|Reactor type(s)||Pressurized water reactor|
|Power generation information|
|Annual generation||22,179 GW·h|
|As of 2009-03-25|
The South Texas Project Electric Generating Station (also known as STPEGS, South Texas Project or STP), is a nuclear power station southwest of Bay City, Texas, United States. The STP 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.
STP was the first nuclear power plant in Texas, beginning operation in 1988. In 1996, the two South Texas units were two of the top 20 electricity-generating nuclear units worldwide.
STP is unique in its design of the safety systems for the reactors. Each unit has three, rather than the customary two, fully independent emergency core-cooling systems (ECCS) and associated support systems. However the addition of the third safety train was not fully recognized and credited by nuclear safety regulations during the plant licensing process. The third ECCS system provides significant real-risk reduction, and the utility undertook efforts to gain regulatory recognition of these features. These efforts led in part to the plant's engineering staff becoming early industry leaders in analytical risk modeling and real-time risk management during operations and maintenance activities.
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.
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 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.
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.
By 1981, the South Texas Project was four years behind schedule and had substantial cost overruns. Brown and Root revised their completion schedule to June, 1989 and the cost estimate to $4.4–$4.8 billion. Brown and Root was relieved as architect in September 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.
Austin voters authorized the City Council on November 3, 1981 to sell the city's 16 percent interest in the STP. 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 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.
 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.
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 msnbc.com. 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.
 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 Project site. South Texas 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 Project site. This was the first full application to be submitted to the NRC since the year 1979. This proposed expansion of the South Texas Project will generate an additional 2,700 MW of electrical generating capacity, which will ultimately double the capacity of the current site. 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, has informed CPS Energy that cost would be "substantially greater," possibly up to $4 billion more. As a result of the escalating cost estimates for units 3 and 4, 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 STP securing construction loan guarantees from the United States Department of Energy.
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. NRG has written off its investment of $331 million in the project.
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. It was not clear at the time why the reactor license application was proceeding.
 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.
 Reactor data
The South Texas Generating Station consist of two operational reactors, two additional are planned.
|Reactor unit||Reactor type||Capacity||Construction started||Electricity grid connection||Commercial operation||Current License Expiration|
|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)||ABWR||1350 MW||0 MW|
|South Texas-4 (planned)||ABWR||1350 MW||0 MW|
- "General Municipal Election: November 17, 1973" City of Austin
- "General Municipal Election: August 14, 1976" City of Austin
- "General Municipal Election: January 20, 1979" City of Austin
- "General Municipal Election: April 7, 1979" City of Austin
- Power Reactor Information System of the IAEA: South Texas
- "General Municipal Election: November 3, 1981" City of Austin
- "About Us" South Texas Project Nucler Operating Company
- Bill Dedman, Nuclear neighbors: Population rises near US reactors, msnbc.com, April 14, 2011 http://www.msnbc.msn.com/id/42555888/ns/us_news-life/ Accessed May 1, 2011.
- "EPC Next Step In CPS Energy's Evaluation of Nuclear Option" CPS Energy
- "NRG Files First Full Application for U.S. Reactor" Bloomberg.com
- "$6.1 million spent to end nuclear deal" Express News CPS Energy STP Expansion Termination Article
- "TEPCO Partners in STP Expansion" STP Press Release
- "CPS Energy sees need for new STP units". World Nuclear News. June 30, 2009. Retrieved 2009-06-28.
- "Nuclear cost estimate rises by as much as $4 billion". October 28, 2009. Retrieved 2009-10-28.
- NRG ends project to build new nuclear reactors
- Matthew L. Wald (April 19, 2011). "NRG Abandons Project for 2 Reactors in Texas". New York Times.
- "Licensing Board to Conduct Hearing Oct. 31 in Rockville, Md., on South Texas Project New Nuclear Reactor Application". US NRC Press Releases. US Federal Government. Retrieved 13 October 2011.
- Bill Dedman, "What are the odds? US nuke plants ranked by quake risk," msnbc.com, March 17, 2011 http://www.msnbc.msn.com/id/42103936/ Accessed April 19, 2011.
- Power Reactor Information System of the IAEA: „United States of America: Nuclear Power Reactors- Alphabetic“
- Power Reactor Information System of the IAEA: „Nuclear Power Reactor Details - SOUTH TEXAS-3“
- Power Reactor Information System of the IAEA: „Nuclear Power Reactor Details - SOUTH TEXAS-4“
- "Milestones". South Texas Project Nuclear Operating Company. Retrieved Jul. 14, 2005.
- "CenterPoint Energy Historical Timeline". CenterPoint Energy. Retrieved Jul. 14, 2005.