Prairie Island Nuclear Power Plant
|Prairie Island Nuclear Generating Plant|
Location of Prairie Island Nuclear Generating Plant in Minnesota
|Location||Red Wing, Minnesota|
|Commission date||Unit 1: December 16, 1973
Unit 2: December 21, 1974
|Nuclear power station|
|Reactor type||pressurized water reactor|
|Units operational||2 x 548 MW|
|Annual generation||8,914 GWh|
The Prairie Island Nuclear Generating Plant is an electricity-generating facility located in Red Wing, Minnesota along the Mississippi River, adjacent to the Prairie Island Indian Community reservation. The nuclear power plant, which began operating in 1973, has two nuclear reactors (pressurized water reactors) manufactured by Westinghouse that produce a total 1,076 megawatts of power. Units 1 and 2 are licensed to operate through 2033 and 2034, respectively.
The plant is owned by Northern States Power Company (NSP), a subsidiary of Xcel Energy, and is operated by Xcel Energy.
Prairie Island is one of two nuclear power plants in Minnesota (the other being Monticello Nuclear Generating Plant in Monticello, MN) and has proven to be the more controversial due to the storage of nuclear waste in large steel casks on-site, an area which is a floodplain of the Mississippi.
In April 2008, Xcel requested that the U.S. Nuclear Regulatory Commission (NRC) renew the licenses of both reactors, extending them for an additional twenty years. The license renewals were approved in June 2011.
The company has also requested the use of a similar storage system at its Monticello plant, which is currently licensed through 2030.
In May 2006 repair workers at the plant were exposed to very low levels of radiation due to inhalation of radioactive iodine-131 (131I) gas. The gas leaked from the steam generators, which were opened for inspection. 131I gas is normally removed by means of a carbon-based filter; in this case the filter had developed a small leak. The NRC deemed this event to be of very low safety significance and notes that it did not result in any overdose.
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 Prairie Island was 27,996, an increase of 4.6 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 2,945,237, an increase of 7.8 percent since 2000. Cities within 50 miles include Minneapolis (39 miles to city center) and St. Paul (32 miles to city center).
Spent fuel storage
NSP had initially intended to send radioactive waste to a storage facility operated by the United States federal government, but no such site is yet open for use (the Yucca Mountain nuclear waste repository is under construction, but following heavy opposition is no longer considered an option by the Obama Administration). In 1991, the company requested permission from the Minnesota Public Utilities Commission to eventually store waste in 48 dry casks on the site. Opposition by environmentalists and the neighboring Prairie Island tribe led the Minnesota Legislature to decrease the number of allowed casks to 17, enough to keep the plant operating through approximately 2003.
Eventually, those casks filled, and Xcel Energy requested that the limit be expanded beyond 17 casks. The legislature granted the request, but required the company to make greater use of renewable energy such as wind power and to pay the local Indian community up to $2.25 million per year to help with evacuation improvements and the acquisition and development of new land and to help pay for a health study and emergency management activities.
Steam Generator Replacement
Operators at Prairie Island Nuclear Generating Plant began a refueling outage on Unit 2 at 12:01 a.m. 9/23/2013. In addition to refueling the reactor, an expanded workforce replaced the unit's two steam generators. Unit 2 was expected to come back online within eight weeks; however, it did not resume operation until January 13, 2014. At 2 AM on January 14th, Unit 2 reached 100% power output.
The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Prairie Island was 1 in 333,333, according to an NRC study published in August 2010.
Xcel Energy performed an emergency shutdown, in late January 2015, of the Unit 1 reactor after a cloud of steam built up in the pressurized cooling system following cooling down process to replace a seal in one of the reactor cooling pumps. The plant returned to full power in February 2015.
Unit 2 of the plant has been shutdown due to an emergency on 5 March 2015 due to a fire alarm at 4:00 am CST. Xcel energy plant operators declared a “notification of an unusual event,” the lowest of four emergency classifications established by the U.S. Nuclear Regulatory Commission.
Unit 2 shut down automatically Dec 17, 2015 due to a turbine problem, and the fire alarm also went off. Operators declared a "notification of unusual event". 
- "Prairie Island Nuclear Generating Plant, Units 1 and 2 - License Renewal Application". Nuclear Regulatory Commission. Retrieved 16 March 2011.
- Karnowski, Steve (June 28, 2011). "Prairie Island nuclear plant licenses renewed". Associated Press. Retrieved 30 June 2011.
- 4Q/2007 Inspection Findings - Prairie Island 2
- 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.
- 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.
- "Prairie Island Nuclear Plant, Minnesota". Energy Information Administration, U.S. Department of Energy (DOE). August 29, 2008. Retrieved 2008-11-22.
- "Prairie Island 1 Pressurized Water Reactor". Operating Nuclear Power Reactors. U.S. Nuclear Regulatory Commission (NRC). February 14, 2008. Retrieved 2008-11-22.
- "Prairie Island 2 Pressurized Water Reactor". Operating Nuclear Power Reactors. NRC. February 14, 2008. Retrieved 2008-11-22.
- Prairie Island Coalition – a group opposing the storage of reactor waste
- Nuclear Tourist: Prairie Island Nuclear Power Plant
- Minnesota Legislative Reference Library: Prairie Island Nuclear Waste Storage