Millstone Nuclear Power Plant#Events

File:Millstone containment structure.jpg at the Millstone Nuclear Power Plant.]]

Millstone 1 was a General Electric boiling water reactor, producing 660 MWe, shut down in November 1995 before being permanently closed in July 1998.

• Construction permit issued: May 19, 1966{{cite book|title=Millstone Nuclear Power Station, Unit 2, Construction: Environmental Impact Statement|url=https://books.google.com/books?id=9WA5AQAAMAAJ|year=1973}}
• Final safety analysis report filed: November 1, 1968
• Provisional operating license issued: October 7, 1970{{cite book|title=Transactions of the American Nuclear Society|url=https://books.google.com/books?id=EJFVAAAAMAAJ|year=1972|publisher=Academic Press}}{{cite book|title=Millstone Nuclear Power Station Unit 3, Operation: Environmental Impact Statement|url=https://books.google.com/books?id=Bek3AQAAMAAJ&pg=PR19|year=1985|pages=19–}}
• Full term operating license issued: October 31, 1986
• Full power license: October 7, 1970
• Initial criticality: October 26, 1970{{cite book|author=Janette Sherman|title=Life's Delicate Balance: Causes and Prevention of Breast Cancer|url=https://books.google.com/books?id=8FJ9AwAAQBAJ&pg=PA73|date=1 May 2014|publisher=Taylor & Francis|isbn=978-1-135-91406-6|pages=73–}}
• Synchronized to the grid: November 1970
• Commercial operation: December 28, 1970
• 100% power: January 6, 1971
• The U.S. Nuclear Regulatory Commission began a safety investigation relating to refueling procedures, based on information provided by George Galatis, a senior nuclear engineer, 1995.{{Cite web |date=December 21, 1995 |title=NRC Failure to Adequately Regulate - Millstone Unit 1 |url=https://www.nrc.gov/docs/ML1526/ML15265A408.pdf |archive-url=https://web.archive.org/web/20090514073255/http://www.nrc.gov/reading-rm/doc-collections/insp-gen/1996/95-077i.pdf |archive-date=May 14, 2009 |access-date=June 21, 2022 |website=U.S. Nuclear Regulatory Commission}}
• Leaking valve forced shutdown multiple equipment failures detected: February 20, 1996
• Permanently ceased operations: July 21, 1998{{cite web|title=Millstone - Unit 1|url=https://www.nrc.gov/info-finder/decommissioning/power-reactor/millstone-unit-1.html|website=US NRC|access-date=17 December 2016}}

Millstone 2 is a Combustion Engineering pressurized water reactor plant built in the 1970s, and has a maximum power output of 2700 thermal megawatts, or MWth (870 MWe). It has 2 steam generators, and 4 reactor cooling pumps. It is{{when|date=June 2023}} 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 filed: August 15, 1972
• Full term operating licensing issued: September 26, 1975
• Full power license: September 26, 1975
• Initial criticality: January 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

Millstone 3 is a Westinghouse plant that started operating in 1986, and has a maximum power output of 3650 MWth (1260 MWe). In the summer of 2008, the NRC approved a power uprate for Unit 3 that increased its electrical output 7.006% to 3650 MWth (1230 MWe). The increase took effect by the end of 2008.{{Cite web |date=August 12, 2008 |title=NRC Approves Power Uprate for Millstone Nuclear Power Plant |url=https://www.nrc.gov/docs/ML0822/ML082250586.pdf |website=U.S. Nuclear Regulatory Commission}}

• 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

In December 1977, two hydrogen explosions occurred at the plant.{{cite book|title=Licensee Contractor and Vendor Inspection Status Report|url=https://books.google.com/books?id=4SVIAQAAMAAJ|year=1978|publisher=Office of Inspection and Enforcement, Nuclear Regulatory Commission}}{{cite journal|author=Mother Jones|title=Mother Jones Magazine|url=https://books.google.com/books?id=r-YDAAAAMBAJ&pg=PA18|date=January 1979|journal=Mother Jones|pages=18–|issn=0362-8841}}

The second explosion injured one man, who required hospitalization.{{cite web|title=Bulletin 78-03: Potential Explosive Gas Mixture Accumulations Associated With BWR Offgas System Operations|url=https://www.nrc.gov/reading-rm/doc-collections/gen-comm/bulletins/1978/bl78003.html|website=Nuclear Regulatory Commission|access-date=17 December 2016}}

In October 1990, operator error during a routine test caused a shutdown of unit 2.{{cite book|author1=Paul W. MacAvoy|author2=Jean W. Rosenthal|title=Corporate Profit and Nuclear Safety: Strategy at Northeast Utilities in the 1990s|url=https://books.google.com/books?id=NEYYkiCeVbUC&pg=PA48|year=2005|publisher=Princeton University Press|isbn=0-691-11994-5|pages=48–}}

In September 1991, twenty reactor operators failed required licensing examinations. The shortfall of licensed operators necessitated a shutdown of unit 1 until March 1992.

In 1995 the U.S. Nuclear Regulatory Commission began a safety investigation relating to refueling procedures at Millstone unit 1, based on information provided by George Galatis, a senior nuclear engineer.

On February 26, 1996, a leaking valve forced the shutdown of units 1 and 2.

Multiple equipment failures were found.{{cite book|author1=Benjamin K. Sovacool|author2=Scott Victor Valentine|title=The National Politics of Nuclear Power: Economics, Security, and Governance|url=https://books.google.com/books?id=CfddxpE6TFwC&pg=PA260|date=16 May 2012|publisher=Routledge|isbn=978-1-136-29437-2|pages=260–}}{{cite book|author=United States. Congress. House. Committee on Commerce. Subcommittee on Energy and Power|title=Oversight hearing on the Nuclear Regulatory Commission: hearing before the Subcommittee on Energy and Power of the Committee on Commerce, House of Representatives, One Hundred Fourth Congress, second session, September 5, 1996|url=https://books.google.com/books?id=LMdojnPASlQC|year=1996|publisher=U.S. Government Printing Office|isbn=978-0-16-053701-1}}

Time magazine featured the plant on its cover, calling its operator a "rogue utility", and the Nuclear Regulatory Commission singled out Millstone for additional attention.

Also in 1996, the plant released one gallon per hour of hydrazine into Long Island Sound.

The plant's operators were convicted in 1999 for falsifying environmental records related to the hydrazine release.

Following the Time article and the subsequent shutdown of all reactors, unit 2 restarted May 11, 1999 and unit 3 restarted July 1, 1998.

Unit 1 was never restarted as the cost of remedying numerous safety issues was too high.{{cite web|last1=Lochbaum|first1=David|title=Longstanding Nuclear Safety Impairments|url=http://allthingsnuclear.org/dlochbaum/longstanding-nuclear-safety-impairments|website=Union of Concerned Scientists|date=24 November 2015|access-date=18 December 2016}}

In 2002 Millstone's operators were fined $288,000 for failing to have properly accounted for two uranium fuel rod components that had been misplaced 30 years earlier in 1972.{{cite book|title=Nuclear Regulatory Commission NRC needs to do more to ensure that power plants are effectively controlling spent nuclear fuel: report to Congressional requesters|url=https://books.google.com/books?id=tDsacGLeeEsC&pg=PA11|publisher= United States Government Accountability Office|isbn=978-1-4289-3176-3|pages=11–12}}

On April 17, 2005, Millstone unit 3 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 on the board.{{cite book|author=John X. Wang|title=Green Electronics Manufacturing: Creating Environmental Sensible Products|url=https://books.google.com/books?id=ZRQmuJkM8PsC&pg=PA29|date=25 July 2012|publisher=CRC Press|isbn=978-1-4398-2669-0|pages=29–}} In response to this event, Millstone implemented a procedure to inspect for these whiskers at every refueling outage, or 18 months.{{Cite web |last=Daddona |first=Patricia |date= |title=Reactor Shutdown: Dominion Learns Big Lesson From A Tiny 'tin Whisker' |url=https://www.theday.com/article/20050704/DAYARC/307049932/0/searc |access-date=June 21, 2022 |website=The Day}}

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.{{Cite web|url=http://www.ctpost.com/news/article/Millstone-2-operating-again-after-shutdown-6891.php#ixzz1GtOgmyQM|title = Millstone 2 operating again after shutdown|date = September 2009}}

On December 21, 2009 the Unit 3 reactor tripped and shut down for longer than 72 hours.{{cite web|title=Preliminary Notification of Event or Unusual Occurrence -- PNO-I-09-007|url=https://www.nrc.gov/docs/ML0935/ML093550301.pdf|website=nrc.gov|access-date=18 December 2016}}

On July 27, 2009, the Unit 2 reactor tripped and shut down for longer than 72 hours.

On August 9, 2013, the Unit 3 reactor tripped and shut down due to a malfunction.

In 2016, unit 3 was shut down following a hydrogen gas leak.{{cite web|title=Millstone Reactor Shuts Down Due to Hydrogen Gas Leak|url=http://www.nbcconnecticut.com/news/local/Millstone-Reactor-Shuts-Down-Due-to-Hydrogen-Gas-Leak-379676311.html|website=nbcconnecticut.com|access-date=17 December 2016}}

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of {{convert|10|mi}}, concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about {{convert|50|mi}}, concerned primarily with ingestion of food and liquid contaminated by radioactivity.{{cite web|url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/emerg-plan-prep-nuc-power-bg.html |title=NRC: Backgrounder on Emergency Preparedness for Nuclear Power Plants |access-date=2012-03-14 |url-status=dead |archive-url=https://web.archive.org/web/20061002131207/http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/emerg-plan-prep-nuc-power-bg.html |archive-date=2006-10-02 }}

The 2010 U.S. population within {{convert|10|mi}} of Millstone was 123,482, an increase of 29.5 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within {{convert|50|mi}} was 2,996,756, an increase of 9.5 percent since 2000. Cities within 50 miles include Hartford (41 miles to city center) and New Haven (43 miles to city center).{{Cite web |date=2011-04-14 |title=Nuclear neighbors: Population rises near US reactors |url=https://www.nbcnews.com/id/wbna42555888 |access-date=2024-08-16 |website=NBC News |language=en}}

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Millstone was 1 in 90,909 for Reactor 2 and 1 in 66,667 for Reactor 3, according to an NRC study published in August 2010.{{Cite web |date=2011-03-16 |title=What are the odds? US nuke plants ranked by quake risk |url=https://www.nbcnews.com/id/wbna42103936 |access-date=2024-08-16 |website=NBC News |language=en}}{{Cite web |date=August 23, 2010 |title=Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States on Existing Plants |url=https://www.nrc.gov/docs/ML1002/ML100270639.pdf |access-date=June 21, 2022 |website=U.S. Nuclear Regulatory Commission}}

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• [https://www.dom.com/about-us/making-energy/nuclear/millstone-power-station Dominion's nuclear page]
• [http://www.eia.doe.gov/cneaf/nuclear/page/at_a_glance/reactors/millstone.html DoE Page]
• [https://web.archive.org/web/20050510055506/http://www.nukeworker.com/pictures/thumbnails81.html NukeWorker]

{{U.S. Nuclear Plants}}

Category:Energy infrastructure completed in 1970

Category:Energy infrastructure completed in 1975

Category:Energy infrastructure completed in 1986

Category:Nuclear power plants in Connecticut

Category:Buildings and structures in New London County, Connecticut

Category:Buildings and structures in Waterford, Connecticut

Category:Nuclear power stations using pressurized water reactors