Davis–Besse Nuclear Power Station

Davis–Besse Nuclear Power Station
Company type	Nuclear power plant
Industry	Electric power generation
Founded	September 1, 1970; 56 years ago in Carroll Township, Ohio, United States
Headquarters	Carroll Township, Ohio, United States
Area served	Ohio, United States
Products	Electricity
Owner	Vistra Corp.

Davis–Besse Nuclear Power Station is a nuclear facility with a capacity of 894 megawatts (MW), situated northeast of Oak Harbor, Ohio, United States. It operates a single pressurized water reactor and is under the ownership and management of Vistra Corp.

This power station has encountered multiple critical safety events impacting its functionality. According to the Nuclear Regulatory Commission (NRC), Davis–Besse is responsible for two of the five most serious nuclear safety incidents in the U.S. since 1979. The most notable occurred in March 2002 when corrosion caused a large hole, roughly the size of a football, in the reactor vessel head. This issue necessitated a shutdown lasting until March 2004 for comprehensive repairs. The NRC levied fines exceeding $5 million—the highest penalty ever imposed on a nuclear facility—against FirstEnergy, which also settled with the Department of Justice for $28 million related to this event.

Originally, Davis–Besse was projected to cease operations by 2020 due to financial challenges competing with natural gas power plants. Plans were updated to reflect a shutdown date of May 31, 2020. Nevertheless, Ohio House Bill 6, enacted in July 2019, introduced a charge on utility bills that funded $150 million annually to support both Davis–Besse and the Perry Nuclear Generating Station, allowing them to remain operational. This legislation later became central to the Ohio nuclear bribery scandal revealed by the DOJ in July 2020.

Location and history

Located on the southwest shore of Lake Erie, the Davis–Besse Nuclear Generating Station lies about north of Oak Harbor, Ohio, occupying a site within Carroll Township. The facility covers , with an adjacent area designated as part of the Ottawa National Wildlife Refuge. Approximately 5 miles east is the entrance to the nearby Magee Marsh Wildlife Area. The plant’s name honors former Toledo Edison Chairman John K. Davis and Cleveland Electric Illuminating Chairman Ralph M. Besse. Construction commenced on September 1, 1970, marking it as the 57th commercial power reactor built in the United States, with operations starting on July 31, 1978.

The single Unit One reactor is an 879 MWe pressurized water design provided by Babcock & Wilcox. It was taken offline from 2002 until early 2004 to undergo safety improvements. In 2012, this unit produced 7,101.7 GWh of electricity. Two additional reactors ordered in 1973 were canceled before construction began in 1981.

Electricity production

**Davis-Besse Nuclear Power Station Electricity Generation (MWh)**
Year	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Annual (Total)
2001	659,778	601,935	655,630	634,920	658,726	633,332	648,532	655,159	637,346	624,363	615,007	659,590	7,684,318
2002	664,299	257,171
890,092
2003
-70,160
2004
48,988	616,820	654,538	635,521	656,635	550,253	636,241	662,232	644,274	663,959	5,722,795

Annual electricity output has fluctuated over time due to periodic maintenance and upgrades. In recent decades, production has generally ranged between roughly 5.7 million and 7.9 million MWh per year.

1977 initial stuck-open pilot-operated relief valve

On September 24, 1977, during a shutdown at 9% reactor power caused by a feedwater system interruption, the pilot-operated relief valve on the reactor pressurizer failed to close properly. This malfunction was an early indicator of the Three Mile Island accident, where a comparable valve remained open, leading to substantial coolant loss.

1985 feedwater supply failure

On June 9, 1985, the main feedwater pumps responsible for delivering water to the reactor steam generators unexpectedly stopped. Efforts to activate auxiliary pumps were unsuccessful as both units tripped due to overspeed, a result of operator mistakes. Initially designated as an NRC "Unusual Event," the situation was subsequently escalated to a "site area emergency" to reflect its increased seriousness.

1998 tornado impact

An F2 tornado struck the plant’s switchyard on June 24, 1998, severing external power and triggering an automatic reactor shutdown at 8:42 pm. An alert was issued at 9:18 pm, while emergency diesel generators maintained essential safety functions until external power was restored.

2002 reactor head corrosion

In March 2002, personnel detected borated water leaking from cracked control rod drive mechanisms that had corroded over six inches (150 mm) of the carbon steel reactor pressure vessel head across an area approximately the size of a football. This deterioration left only the stainless steel cladding intact, containing high-pressure (~2155 psi, 14.6 MPa) reactor coolant. A breach at this site could have resulted in a severe loss-of-coolant accident, releasing coolant into the containment structure and initiating emergency safety protocols. The damage also posed a threat to nearby control rod drive mechanisms, potentially hindering reactor shutdown capabilities.

Subsequent evaluations revealed major safety concerns involving:

the containment sump used for reclaiming reactor coolant;
high-pressure injection pumps;
emergency diesel generators;
containment air coolers;
reactor coolant isolation valves; and
electrical distribution systems.

Remediation efforts included extensive repairs and engineering enhancements over two years at a cost of $600 million. The Davis–Besse reactor resumed operation in March 2004. FirstEnergy procured the replacement reactor vessel head from the decommissioned Midland Nuclear Power Plant in Michigan.

The Nuclear Regulatory Commission ranked this event as the fifth most severe nuclear incident in the United States since 1979 and levied its largest penalty—exceeding $5 million—against FirstEnergy for failures related to corrosion.

Criminal prosecutions

In January 2006, FirstEnergy, the proprietor of Davis–Besse, admitted to safety violations committed by former staff members and entered into a deferred prosecution agreement with the United States Department of Justice (DOJ) concerning the March 2002 event. The NRC's decision to defer prosecution was influenced by engineering assessments that initially deemed inspections sufficient, although subsequent evaluations demonstrated these inspections were inadequate. Due to FirstEnergy's cooperative stance, more severe penalties were avoided. The company agreed to a $28 million settlement, which comprised $23.7 million in fines and $4.3 million allocated to organizations such as the National Park Service, U.S. Fish and Wildlife Service, Habitat for Humanity, and the University of Toledo, in addition to covering investigative expenses.

Indictments were issued against two former employees and one contractor for deliberately hiding evidence of reactor pressure vessel corrosion caused by boric acid, with potential sentences reaching up to 25 years imprisonment. The indictment also referenced other employees who provided false information but did not identify them by name. In 2007, one individual was found guilty while another was acquitted of concealing information from the NRC; a subsequent trial in 2008 resulted in the conviction of the remaining engineer on similar charges.

2003 slammer worm computer virus

In January 2003, the plant’s internal network was compromised by the slammer worm, leading to a disruption in safety monitoring systems lasting approximately five hours.

2008 discovery of tritium leak

On October 22, 2008, both the NRC and the Ohio Environmental Protection Agency were alerted to a tritium leak identified during a fire safety inspection. Initial assessments indicated no radioactive water had escaped beyond the plant’s groundwater boundaries.

2010 replacement reactor head problems

During a refueling outage in 2010, ultrasonic examinations revealed that two control rod drive mechanism nozzles within the reactor vessel closure head did not meet acceptance standards. Further scrutiny uncovered new cracks in 24 out of 69 nozzles, including one that exhibited boric acid leakage. Repairs employing established methods were completed before operations resumed later that year. Replacement of the reactor vessel head was planned for 2011.

2011 shield building cracks

A maintenance shutdown conducted in October 2011 exposed a hairline crack measuring approximately 30 feet within the concrete shield building encasing the containment vessel.

2012 reactor coolant pump seal pinhole leak

On June 6, 2012, routine inspection detected a minor pinhole leak estimated at about 0.1 gallons per minute in a seal weld of a reactor coolant pump. The facility operated under limited conditions while an investigation into the root cause was underway.

2015 steam leak incident and shutdown

On May 9, 2015, a steam leak occurred within the turbine building, leading FirstEnergy personnel to declare an Unusual Event and initiate a reactor shutdown for necessary repairs. The facility recommenced operations and reconnected to the local electrical grid by May 12.

Future outlook

The plant's initial operating license reached its expiration on April 22, 2017. FirstEnergy Nuclear Operating Company (FENOC) expressed its intent to pursue renewal in August 2006 and formally submitted the application on August 10, 2010. The Nuclear Regulatory Commission approved a two-decade extension on December 8, 2015, prolonging the license until April 22, 2037.

On March 31, 2018, FENOC filed for bankruptcy protection and announced intentions to decommission the nuclear facility. In 2019, Ohio legislators considered implementing a $9 per megawatt-hour subsidy aimed at maintaining Davis–Besse’s operation. Following the enactment of House Bill 6 on July 23, 2019, FirstEnergy declared plans to refuel the plant and withdraw its previous shutdown notification.

Subsequent investigations uncovered that House Bill 6 was linked to a corruption scheme involving FirstEnergy disbursing roughly $61 million to Ohio House Speaker Larry Householder and his associates to ensure the bill’s passage and prevent its repeal. Householder was convicted, removed from office, and sentenced to two decades in prison; one co-conspirator died by suicide.

Seismic hazard

According to a 2010 assessment by the Nuclear Regulatory Commission, the likelihood of an earthquake causing core damage at Davis–Besse is estimated at one in 149,254 annually.

Population in proximity

The NRC designates two emergency planning zones surrounding nuclear facilities: a 10-mile radius plume exposure pathway zone focused on airborne radioactive hazards, and a broader 50-mile ingestion pathway zone addressing risks from contaminated food and beverages.

In 2010, the population residing within 10 miles of Davis–Besse was recorded at 18,635, reflecting a growth of 14.2% over ten years. Within the larger 50-mile radius, the population was approximately 1,791,856, marking a modest increase of 1.4% since 2000. Cities located within this range include Sandusky (22 miles), Toledo (26 miles), and Detroit (50 miles). Canadian cities such as Leamington (39 miles) and Windsor (49 miles) also lie within this area.

The plant’s cooling tower stands at 493 feet tall and serves as a notable landmark visible across the western portion of Lake Erie, including views from both Michigan’s and Ontario’s shores, contributing to its regional prominence.

External links