South Texas Nuclear Generating Station
Encyclopedia
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 (49 km²) site on the Colorado River
about 90 miles (145 km) southwest of Houston
. It consists of two Westinghouse
Pressurized Water Reactor
s and is cooled by a 7000 acres (28.3 km²) 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.
, 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.
at 44 percent, San Antonio municipal utility CPS Energy
at 40 percent and Austin Energy
at 16 percent.
defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16.1 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80.5 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.
The 2010 U.S. population within 10 miles (16.1 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 (80.5 km) was 254,049, an increase of 10.2 percent since 2000. Cities within 50 miles include Lake Jackson (40 miles to city center).
filed a Letter Of Intent with the Nuclear Regulatory Commission
to build two 1,358-MWe Advanced Boiling Water Reactor
s (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.
Bay City, Texas
Bay City is a city in Matagorda County, Texas, United States. The population was 18,667 at the 2000 census. It is the county seat of Matagorda County. The current mayor is Mark Bricker.-Geography:Bay City is located at...
, United States. The STP occupies a 12,200 acre (49 km²) site on the Colorado River
Colorado River (Texas)
The Colorado River is a river that runs through the U.S. state of Texas; it should not be confused with the much longer Colorado River which flows from Colorado into the Gulf of California....
about 90 miles (145 km) southwest of Houston
Houston, Texas
Houston is the fourth-largest city in the United States, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of . Houston is the seat of Harris County and the economic center of , which is the ...
. It consists of two Westinghouse
Westinghouse Electric Company
Westinghouse Electric Company LLC is a nuclear power company, offering a wide range of nuclear products and services to utilities throughout the world, including nuclear fuel, service and maintenance, instrumentation and control and advanced nuclear plant designs...
Pressurized Water Reactor
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
s and is cooled by a 7000 acres (28.3 km²) reservoir, which eliminates the need for cooling towers.
STP was the first nuclear power plant in Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, 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
Nuclear safety
Nuclear safety covers the actions taken to prevent nuclear and radiation accidents or to limit their consequences. This covers nuclear power plants as well as all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power,...
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.
History
On December 6, 1971, Houston Lighting & Power Co. (HL&P), the City of AustinAustin, Texas
Austin is the capital city of the U.S. state of :Texas and the seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 14th most populous city in the United States. It was the third-fastest-growing large city in...
, the City of San Antonio
San Antonio, Texas
San Antonio is the seventh-largest city in the United States of America and the second-largest city within the state of Texas, with a population of 1.33 million. Located in the American Southwest and the south–central part of Texas, the city serves as the seat of Bexar County. In 2011,...
, and the Central Power and Light Co. (CPL) initiated a feasibility study
Feasibility study
Feasibility studies aim to objectively and rationally uncover the strengths and weaknesses of the existing business or proposed venture, opportunities and threats as presented by the environment, the resources required to carry through, and ultimately the prospects for success. In its simplest...
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
Kellogg, Brown and Root
KBR, Inc. is an American engineering, construction and private military contracting company, formerly a subsidiary of Halliburton, headquartered in Houston. The company also has large offices in Arlington, Birmingham, Newark, Delaware and Leatherhead, UK. After Halliburton acquired Dresser...
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
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
(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
Criticality
Criticality may refer to:* Critical thinking in education* Critical reflection in adult education* Critical mass in nuclear reactions* Criticality accident* Criticality matrix* Nuclear Criticality Safety...
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.
Ownership
The STPEGS reactors are operated by the STP Nuclear Operating Company (STPNOC). Ownership is divided among NRG EnergyNRG Energy
NRG Energy, Inc. is an American energy company headquartered in West Windsor Township, New Jersey, near Princeton.-Electrical Power Generation Operations:...
at 44 percent, San Antonio municipal utility CPS Energy
CPS Energy
CPS Energy of San Antonio, Texas is the United States' largest municipally owned utility company, with combined natural gas and electric service. Fourteen percent of all utility revenues are returned to the City of San Antonio, and those revenues make up more than 20 percent of the City of San...
at 40 percent and Austin Energy
Austin Energy
Austin Energy is the public utility providing electrical power service to a area including Austin, Texas and parts of the surrounding area in Travis and Williamson counties...
at 16 percent.
Surrounding population
The Nuclear Regulatory CommissionNuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16.1 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80.5 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.
The 2010 U.S. population within 10 miles (16.1 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 (80.5 km) was 254,049, an increase of 10.2 percent since 2000. Cities within 50 miles include Lake Jackson (40 miles to city center).
Recent developments
On June 19, 2006, NRG EnergyNRG Energy
NRG Energy, Inc. is an American energy company headquartered in West Windsor Township, New Jersey, near Princeton.-Electrical Power Generation Operations:...
filed a Letter Of Intent with the Nuclear Regulatory Commission
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
to build two 1,358-MWe Advanced Boiling Water Reactor
Advanced Boiling Water Reactor
The Advanced Boiling Water Reactor is a Generation III boiling water reactor. The ABWR is currently offered by GE Hitachi Nuclear Energy and Toshiba...
s (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
NRG Energy
NRG Energy, Inc. is an American energy company headquartered in West Windsor Township, New Jersey, near Princeton.-Electrical Power Generation Operations:...
filed a full application with the NRC
NRC
NRC may refer to:Research centres and other establishments* National Research Centre, Egypt* National Research Council * Nokia Research Center* United States National Research CouncilOther educational* National Resource Center, U.S...
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 | |
|---|---|---|---|---|---|---|---|
| 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) | ABWR | 1350 MW | 0 MW | ||||
| South Texas-4 (planned) | ABWR | 1350 MW | 0 MW | ||||
Sources
- "Milestones". South Texas Project Nuclear Operating Company. Retrieved Jul. 14, 2005.
- "CenterPoint Energy Historical Timeline". CenterPoint Energy. Retrieved Jul. 14, 2005.