Davis–Besse Nuclear Power Station

Template:Fix bunching Template:Infobox Nuclear power plant Template:Nuke-NRC3 Template:Fix bunching Davis-Besse Nuclear Power Station is a nuclear power plant with a single pressurized water reactor, also referred to as a light water reactor. As of 2006, it is operated by the FirstEnergy Nuclear Operating Company subsidiary of FirstEnergy Corp. The power station is located on the southwest shore of Lake Erie about 10 miles north of Oak Harbor, Ohio and is on the north side of highway 2 just east of highway 19 on a 954 acre site in the Carroll Township. The plant only utilizes 221 acres with 733 acres devoted to the Ottawa National Wildlife Refuge. The entrance to the Magee Marsh Wildlife Area is less than a mile east of the power station. The official name according to the U.S. Energy Information Administration is the Davis-Besse Nuclear Generating Station. It is the 57th commercial power reactor to commence building in the United States of America (construction began on September 1, 1970) and the 50th to come on-line July 31, 1978. The plant was originally jointly owned by Cleveland Electric Illuminating (CEI) and Toledo Edison (TE) and was named for former TE Chairman John K. Davis and former CEI Chairman Ralph M. Besse.

According to the Nuclear Regulatory Commission, Davis-Besse has been the source of two of the top five most dangerous nuclear incidents in the United States since 1979.

Unit One

Unit One is an 879 MWe pressurized water reactor supplied by Babcock and Wilcox. The reactor was shut down from 2002 until early 2004 for safety repairs and upgrades, so recent operational statistics are not yet available for the unit.

The reactor head under inspection

Incident history

Over the years of its operation, the plant has experienced several incidents, none of which have resulted in exposure to dangerous levels of radiation.

First stuck-open pilot-operated relief valve

On September 24, 1977, the reactor, running at only 9% power, shut down because of a disruption in the feedwater system. This caused the relief valve for the steam generator to stick open. As of 2005, the NRC considers this to be the fourth highest ranked safety incident.

Loss of feedwater event

On June 9, 1985, the main feedwater pumps, used to supply water to the reactor steam generators, shut down. A control room operator then attempted to start the auxiliary (emergency) feedwater pumps. These pumps both tripped on overspeed conditions because of operator error. This incident was originally classified an "unusual event" (the lowest classification the NRC uses) but it was later determined that it should have been classified a "site area emergency".

Tornado

On June 24, 1998 the station was struck by an F2 tornado. The plant's switchyard was damaged and access to external power was disabled. The plant's reactor automatically shut down at 8:43 pm and an alert (the next to lowest of four levels of severity) was declared at 9:18 pm. The plant's emergency diesel generators powered critical facility safety systems until external power could be restored.

Erosion of the 6-inch thick carbon steel reactor head, caused by a persistent leak of borated water.

Reactor head hole

In March 2002, it was discovered that boric acid had eaten through more than six inches of the 6½-inch thick reactor pressure vessel head (see photo). A breach might have partially flooded the reactor's containment building with reactor coolant, and resulted in emergency safety procedures to protect from core damage. The resulting corrective maintenance took two years. Repairs and upgrades cost $600 million, and the Davis-Besse reactor was restarted in March 2004. The U.S. Justice Department investigated and penalized the owner of the plant over safety and reporting violations related to the incident.

Criminal prosecutions

On January 20, 2006, the owner of Davis-Besse, FirstEnergy Corporation of Akron, Ohio, acknowledged a series of safety violations by former workers, and entered into a deferred prosecution agreement with the U.S. Department of Justice. The deferred prosecution agreement relates to the March 2002 incident (see above). The deferment granted by the NRC were based on letters from Davis-Besse engineers stating that previous inspections were adequate. However, those inspections were not as thorough as the company suggested, and as proved by the material deficiency discovered later. In any case, because FirstEnergy cooperated with investigators on the matter, they were able to avoid more serious penalties. Therefore, the company agreed to pay fines of $23.7 million, with an additional $4.3 million to be contributed to various groups, including the National Park Service, the U.S. Fish and Wildlife Service, Habitat for Humanity, and the University of Toledo as well as to pay some costs related to the federal investigation.

Two former employees and one former contractor were indicted for statements made in multiple documents and one videotape, over several years, for hiding evidence that the reactor pressure vessel was being corroded by boric acid. The maximum penalty for the three is 25 years in prison. The indictment mentions that other employees also provided false information to inspectors, but does not name them.

2008 discovery Tritium leak

The NRC and Ohio EPA were notified of a tritium leak accidentally discovered during an unrelated fire inspection on October 22, 2008. Preliminary indications suggest radioactive water did not infiltrade groundwater outside plant boundaries

2009 accidental shooting

In November 2009, a plant security guard accidentally shot himself while in the locker room. The injuries sustained were not life-threatening

2010 Replacement reactor head problems

After the 2002 incident, Davis-Besse purchased a used replacement head from a mothballed reactor in Midland, Michigan. Davis-Besse operators replaced the original cracked reactor head before restarting in 2004.On March 12, 2010, during a scheduled refueling outage, ultrasonic examinations performed on the control rod drive mechanism nozzles penetrating the reactor vessel closure head identified that two of the nozzles inspected did not meet acceptance criteria. NRC investigators subsequently found new cracks in 24 of 69 nozzles, including one serious enough to leak boric acid. Root cause analysis is currently underway by the Department of Energy, First Energy, and the NRC to determine the cause of the premature failures.

Control Rod Drive Hot Cracking/ Replacement

Both indications required repair prior to returning the vessel head to service. Subsequent extent of condition examinations determined repairs are required to several additional nozzles. The control rod drive nozzle issues are expected to be resolved by AREVA nuclear, using techniques proven at other nuclear facilities. The plant was expected to resume operation in summer 2010.

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Davis-Besse as seen from Route 2 in 2005. (Photo courtesy of Shawn Mariani of otchster.com)

Future

The facility's original nuclear operating license expires on April 22, 2017. On August 11, 2006 FirstEnergy Nuclear Operating Company (FENOC) submitted a letter of intent (Adams Accession No. ML062290261). The submission date for the application is August 10, 2010. This initiates a long process that results in an application approval or revocation. Public hearings are a vital part of any application review and information on this process can be found on the U.S. Nuclear Regulatory Commission (NRC) website at NRC.gov. [4]. The site map contains many valuable links

External links

• "Davis-Besse Nuclear Generating Station, Ohio". Energy Information Administration, U.S. Department of Energy (DOE). October 3, 2008. Retrieved 2008-11-19.
• "Davis-Besse Pressurized Water Reactor". Operating Nuclear Power Reactors. U.S. Nuclear Regulatory Commission (NRC). February 14, 2008. Retrieved 2008-11-19.
• [5]
• Union of Concerned Scientists report on Davis-Besse
• U.S. Nuclear Regulatory Commission's "Davis-Besse Lessons Learned Task Force" (with links to the Task Force Report)