Prairie Island Nuclear Power Plant

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone has a radius of , and is related primarily to exposure to, and inhalation of, airborne radioactive contamination. Secondly, an ingestion pathway zone with a radius of about , is concerned primarily with ingestion of food and liquid by residents that could be contaminated by radioactivity. The 2010 U.S. population within 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. The 2010 U.S. population within 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 from this plant 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 given strong opposition in the region, the Obama administration no longer thought this was an option.) In 1991, Xcel Energy had requested permission from the Minnesota Public Utilities Commission to eventually store waste in 48 dry casks on the Prairie Island site. Opposition by environmentalists and the neighboring Prairie Island tribe led the Minnesota Legislature to decrease the number of allowed casks to 17; this was sufficient to keep the plant operating through approximately 2003. When those casks filled, 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 in generating power, such as wind power. In addition, it was required to pay the adjacent Prairie Island Indian Community up to $2.25 million per year to help with evacuation improvements, and the acquisition and development of new land for their reservation. In addition, this money was to help pay for a health study and emergency management activities by the small tribe. ==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 14, Unit 2 reached 100% power output. ==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 Prairie Island was 1 in 333,333, according to an NRC study published in August 2010. == Emergency shutdowns ==

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 a 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 shut down due to an emergency on 5 March 2015, indicated by 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 on December 17, 2015, due to a turbine problem, and the fire alarm went off at the time. Operators declared a "notification of unusual event". On May 27, 2023, Xcel Energy reported that Prairie Island Unit 2 automatically shut down after an "unusual event" was declared due to a malfunctioning external transformer. This triggered fire alarms, though no fire was found, nor was there a safety threat to staff or the public. Resident inspectors from the U.S. Nuclear Regulatory Commission (NRC) verified that the plant was in a safe condition. Unit 1 continued normal operations, and Unit 2 was expected to resume service later that week pending repairs and standard restart procedures. Prairie Island Unit 2 was taken offline on November 22, 2023, for its routine refueling cycle. Shortly thereafter, Unit 1 was shut down due to an electrical issue between the turbine and the electric grid. Xcel Energy said the power plant outage would last until January but would not affect customer service. ==Hydrogen production==

Prairie Island will start producing green hydrogen from high-temperature electrolysis. Xcel Energy is going to build two natural gas power plants that can use a mix of 30% hydrogen. Natural gas power plants could be replaced/retrofitted with combined cycle hydrogen power plants to transition away from hydrocarbons. Ships and trains could also run on hydrogen fuel cells. ==See also==