Monticello Nuclear Generating Plant

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Monticello Nuclear Generating Plant
Country United States
Location Monticello, Minnesota
Coordinates 45°20′1″N 93°50′57″W / 45.33361°N 93.84917°W / 45.33361; -93.84917Coordinates: 45°20′1″N 93°50′57″W / 45.33361°N 93.84917°W / 45.33361; -93.84917
Status Operational
Commission date June 30, 1971
Owner(s) Xcel Energy
Operator(s) Xcel Energy Nuclear Department
Nuclear power station
Reactor type BWR-3
Reactor supplier General Electric
Power generation
Units operational 1 x 671 MW
Annual generation 4,192 GWh
Website
[3]

The Monticello Nuclear Generating Plant is a nuclear power plant located in Monticello, Minnesota, along the Mississippi River. The site, which began operating in 1971, has a single nuclear reactor (boiling water reactor) of the General Electric BWR-3 design generating 671 MWe.

Currently the plant is both owned and operated by Xcel Energy [1] The reactor was originally licensed to operate until 2010, however on November 8, 2006, it was extended to operate until 2030.

Surrounding population[edit]

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.[2]

The 2010 U.S. population within 10 miles (16 km) of Monticello was 62,976, an increase of 36.5 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 2,977,934, an increase of 8.6 percent since 2000. Cities within 50 miles include Minneapolis (38 miles to city center) and St. Paul (45 miles to city center).[3]

Incidents and updates[edit]

Roughly 1,300 gallons of radioactive water which accidentally leaked from the plant into the Mississippi River in an incident on 5 May 1982, was determined to be "no threat" to the public.[4]

The Monticello Nuclear Power Plant Control Room Simulator

In January 2007 a 13-ton control box fell eight to twelve inches and caused an unexpected shutdown. This control box was located in the condenser room of the turbine building and contained valves which controlled steam pressure. Emergency response teams at the station deemed that the event was likely caused by inadequate welds at the time of installation and fatigue due to vibrations over the life of the plant.

Construction of the on-site independent spent fuel storage installation (ISFSI) pad began in June 2007. The target date for the completion of the pads is December 2007 with insertion of the first ten dry storage containers (holding spent fuel assemblies) into horizontal storage modules (HSMs) in mid-2008. Initially, 12 HSMs will be placed on the storage pad. Each HSM — a thick, reinforced, pre-cast concrete structure about the size of a single car garage —  has the capacity to hold 61 fuel bundles.

On September 11, 2008, a cable fault tripped the transformer which supplied power to the site. This resulted in a loss of off-site power and the plant automatically shut down.[5]

On September 18, 2008, an employee for a rental equipment company was electrocuted by one phase of the 115-kV power line outside of the plant due to a lack of situational awareness. The individual was raising a bucket lift without watching overhead and contacted one phase of the 115-kV line. The plant was offline at the time due to the forced outage described above.[6]

In February 2011, the site's plant officials determined that four control rod blades could be affected by a potentially substantial safety hazard. Vice President Tim O'Connor indicated that the blades would be replaced in March.[7][8]

Update as Required for License Extension[edit]

In March 2013, the plant was shut down for a routine refueling. During this time, workers replaced several plant components. This increased the plant's electrical output from the original 600 MWe to 671 MWe. Due to Xcel's excellent maintenance of Monticello since its commission in 1971, these were the original components installed when the plant opened. In early August, the plant was brought back online with the new equipment.

Seismic risk[edit]

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Monticello was 1 in 52,632, according to an NRC study published in August 2010.[9][10]

References[edit]

  1. ^ "Nuclear plant operating licenses transferred to Xcel Energy operating utility". Xcel Energy. 2008-09-22. Retrieved 2011-03-24. 
  2. ^ http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/emerg-plan-prep-nuc-power-bg.html
  3. ^ 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.
  4. ^ "Reactor leak 'no threat'". The Montreal Gazette. May 5, 1982. Retrieved March 24, 2011. 
  5. ^ [1][dead link]
  6. ^ [2][dead link]
  7. ^ "Possible fuel rod hazard at Xcel's Monticello nuclear plant". Star Tribune. February 16, 2011. 
  8. ^ Gram, Dave (February 17, 2011). "Possible fuel rod hazard seen at some nuke plants". BusinessWeek. 
  9. ^ 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.
  10. ^ http://msnbcmedia.msn.com/i/msnbc/Sections/NEWS/quake%20nrc%20risk%20estimates.pdf

footnote number 6:

Nuclear Regulatory Commission, Preliminary Notification – Region III, Sept. 15, 2008, Preliminary Notification Of Event Or Unusual Occurrence - PNO-III-08-009; <http://pbadupws.nrc.gov/docs/ML0825/ML082590668.pdf>

External links[edit]