The Millstone Nuclear Power Plant is the only nuclear power generation site in Connecticut. It is located at a former quarry (from which it takes its name) in Waterford. Of the three reactors built here, units two and three are still operating at a combined output rating of 2020 MWe.

The Millstone Nuclear Power Plant covers about 500 acres (2 km²). The power generation complex was built by a consortium of utilities, using Niantic Bay (which is connected to Long Island Sound and the Atlantic Ocean) as a source of coolant water.

Although located in Waterford, Millstone is most clearly seen from downtown Niantic. It is visible from the Niantic Boardwalk area and from the Niantic River Bridge, and is also visible to Amtrak customers on the NEC line which as it skirts Niantic Bay.

Millstone Nuclear Power Plant earned OSHA's top award for workplace safety on October 14, 2004, and earned the Top Industry Practice/ Framatone ANP Vendor Award for its work developing novel ultrasonic leak inspection techniques in March 2001.^[2]

Millstone Nuclear Power Plant Units 2 and 3, both pressurized water reactors (one from Westinghouse and one from Combustion Engineering), were sold to Dominion by Northeast Utilities in 2000 and continue to operate.

On November 28, 2005, after a 22-month application and evaluation process, Millstone was granted a 20-year license extension to both units 2 and 3 by the NRC.

Unit 1

Millstone 1 was a General Electric boiling water reactor, producing 660 MWe, shut down in November 1995 before being permanently closed in July 1998. On February 20, 1996 a leaking valve forced the shutdown of this unit, and unit 2; multiple equipment failures were found.

• Construction Permit Issued: May 19, 1966
• Final Safety Analysis Report (FSAR) Filed: November 1, 1968
• Provisional Operating License Issued: October 7, 1970
• Full Term Operating License Issued: October 31, 1986
• Full Power License: October 7, 1970
• Initial Criticality: October 26, 1970
• Synchronized to the Grid: November 1970
• Commercial Operation: December 28, 1970
• 100% Power: January 6, 1971
• Leaking valve forced shutdown multiple equipment failures detected: February 20, 1996
• Permanently Ceased Operations: July 21, 1998

Unit 2

Millstone 2 is a Combustion Engineering plant built in the 1970s, and has a maximum power output of 2700 MWth (870 MWe). It has 2 steam generators, and 4 reactor cooling pumps (RCP). It is currently undergoing an upgrade to its safe shutdown system which already met NRC standards. During its refueling outage in October 2006, the operator installed a new pressurizer.

• Construction Permit Issued: December 11, 1970
• Final Safety Analysis Report (FSAR) Filed: August 15, 1972
• Full Term Operating Licensing Issued: September 26, 1975
• Full Power License: September 26, 1975
• Initial Criticality: October 17, 1975
• Commercial Operation: December 26, 1975
• 100% Power: March 20, 1976
• “Stretch Power”: June 25, 1979
• Operating License Extension Requested: December 22, 1986
• Operating License Extension Issued: January 12, 1988
• Full Term Operating License Expires: December 11, 2010
• Operating License Expires: July 31, 2015
• Extended Operating License Expires: July 31, 2035

Unit 3

Millstone 3 is a Westinghouse plant that started operating in 1986, and has a maximum power output of 3411 MWth (1150 MWe). Recently, the NRC approved a power uprate for Unit 3 that will increase its electrical output 7.006% to 3650 MWth (1230 MWe. The increase will take effect by the end of 2008.

• Construction Permit Issued: August 9, 1974
• Initial Criticality: January 23, 1986
• Commercial Operation: April 23, 1986
• Operating License Expires: November 25, 2025
• Extended Operating License Expires: November 25, 2045

Events and Nuclear Accident

• On February 26, 1996, A leaking valve forced the shutdown of units 1 and 2, multiple equipment failures were found.
• On April 17, 2005, Millstone plant safely shut down without incident when a circuit board monitoring a steam pressure line short-circuited, which caused the board to malfunction and indicate an unsafe drop in pressure in the reactor's steam system, when in reality there was no drop in steam pressure. The cause was attributed to "tin whiskers". In response to this event, Millstone implemented a procedure to inspect for these whiskers at every refueling outage, or 18 months. David Lochbaum, a scientist affiliated with the Union of Concerned Scientists, while remaining critical of the processes leading to the discovery of the whiskers, praised Millstone for its handling of the situation.
• In September, 2009, unit-2 shut down when an electrical storm caused power fluctuations. When workers tried to restart the unit, they discovered a small leak in the reactor coolant pump.
• 12/21/2009 Millstone Unit 3 Reactor Trip and Shutdown Greater Than 72 Hours.
• 07/27/2009 Millstone Unit 2 Reactor Trip and Shutdown Greater Than 72 Hours

Millstone Nuclear Power Plant
Country	United States
Locale	Waterford, Connecticut
Status	Operational
Commission date	Unit 2: December 26, 1975 Unit 3: April 23, 1986
Licence expiration	Unit 2: July 31, 2035 Unit 3: November 25, 2045
Construction cost	Unit 2: $424 million Unit 3: $3.77 billion
Operator(s)	Dominion
Architect(s)	Unit 2: Bechtel Unit 3: Stone & Webster
Reactor information
Reactor type(s)	PWR
Reactor supplier(s)	Unit 2: Combustion Engineering Unit 3:Westinghouse
Power generation information
Installed capacity	Unit 2: 882 MW Unit 3: 1,155
Annual generation	Unit 2: 7,686 GWh Unit 3: 8,699