Fort Calhoun Nuclear Generating Station
Encyclopedia
The Fort Calhoun Nuclear Generating Station is a nuclear power plant
located on 660 acres (267.1 ha) between Fort Calhoun
, and Blair, Nebraska
adjacent to the Missouri River
between mile markers 645.6 and 646.0. The utility has an easement
for another 580 acres (234.7 ha) which is maintained in a natural state. The power plant is owned and operated by the Omaha Public Power District
of Omaha, Nebraska
and accounts for 25 percent of OPPD's net generation capabilities.
This plant has one Combustion Engineering
pressurized water reactor
generating 484 megawatts of electricity. This is currently the smallest rated capacity among all operating commercial power reactors in North America, and as a single-unit plant, this also qualifies it as the smallest rated capacity nuclear power plant. OPPD's two Nebraska City
coal-fired plants at 682 (opened 2009) and 649 (opened 1979) MW are both significantly larger.
Fort Calhoun houses spent fuel rods in a 40 foot deep spent fuel pool
next to the reactor, and when the pool had nearly reached capacity in 2006, OPPD began to store spent fuel rods above ground in dry cask storage
as well. In total, the Ft. Calhoun reactor has 600,000 to 800,000 pounds of high level nuclear waste. The storage was not designed to house spent fuel permanently, but when plans for Yucca Mountain nuclear waste repository were terminated, OPPD stated that they are "prepared to safely store material on-site as long as necessary".
The plant underwent refurbishment in 2006 by having its steam generators
, pressurizer, reactor vessel head, low pressure turbines and main transformer replaced. In 2003, the plant had its operating license renewed for an additional twenty years. With the renewal, the license for Fort Calhoun was extended from August 9, 2013, to August 9, 2033.
The 2011 Missouri River floods
surrounded the plant with flood water, an unprecedented event for a U.S. nuclear power plant due to both the level of flooding and the anticipated period of time the flood is expected to persist.
defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of about 10 miles (16.1 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80.5 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity. In 2010, the population within 10 miles of Fort Calhoun was 20,639; the population within 50 miles was 953,410. The closest major city is Omaha, with a population of 408,958, whose center is 18 miles (29 km) from the plant.
ing event and though by June 14, 2011, much of the facility was surrounded by the swollen Missouri River, Omaha Public Power District officials were confident that enough redundancies were in place to ensure adequate safety. It was reported on June 17, 2011 that the plant was in "safe cold shutdown" mode for refueling and the anticipation of flooding, and that four weeks worth of additional fuel had been brought in to power backup generators, should they be needed. The Army Corps of Engineers
indicated that with average precipitation, the Missouri River would not go above 1008 feet (307.2 m) above sea level and OPPD officials stated that the current flood protection efforts would protect the plant to 1010–1012 ft (307.8–308.5 ) feet above sea level. Officials indicated the spent fuel pool is at 1038.5 feet (316.5 m) above sea level.
On June 7, 2011, an electrical component in a switch gear room caused a small fire with Halon extinguisher activation which forced a partial evacuation. The fire was no longer burning when the on site fire brigade arrived and according to officials, the public was never in any danger. The fire impacted pumping of coolant water through the spent fuel pool. Cooling was interrupted for 90 minutes while the estimated time for the pool to reach boiling temperature was over 88 hours. In response, the Omaha Public Power District declared an alert (second level on a 4 level taxonomy). The evacuation was the first at the facility since 1992, when 20000 gallons (75,708.2 l) (ca. 76 t
) of coolant leaked into a containment building from the reactor.
On June 23 a helicopter contracted by OPPD to survey transmission lines made an unplanned landing 1.5 miles south of the plant. Reports described it as an unplanned landing although photographs showed it on its side in a field. Nobody was injured. The Federal Aviation Administration
had declared a "temporary flight restriction," in a two nautical mile radius, centered on the Fort Calhoun nuclear facility. This restriction went into effect on June 6, 2011, at 4:31 PM, and remains in effect "until further notice." Officials noted that the June 6 FAA directive was actually a reminder to a standing order creating no flight zones over all U.S. nuclear power plants which had been in effect after the 2001 9/11 attacks.
On June 26, at 1:30 a.m., a 8 feet (2.4 m) high, 2000 feet (609.6 m) long water filled rubber flood berm surrounding portions of the plant, was punctured by a small earth mover ("Bobcat") and collapsed. The collapse of the flood berm allowed flood waters to surround the auxiliary and containment buildings at the plant, and also forced the temporary transfer of power from the external electricity grid to backup electrical generators. It was reported more than 2 foot (0.6096 m) of water rushed in around buildings and electrical transformers. Backup generators were then used to ensure the facility maintained electrical power for cooling. The rupturing of the flood berm also resulted in approximately 100 gallons (378.5 l) of petroleum being released into the river as many fuel containers were washed out. The fuel/oil containers were staged around the facility to supply fuel for pumps which remove water within the flood containment barriers. The rubber berm was a secondary measure not mandated by the NRC and was put in place by OPPD to provide additional room for work immediately outside the reactor buildings. According the NRC, the water-filled berm "protects several pieces of equipment that have been brought onsite, including an additional emergency diesel generator for supplying AC electrical power, water pumps, firefighting equipment and sandbagging supplies".
According to OPPD, the plant is designed to withstand waters up to 1,014 feet above mean sea level. The river is not expected to exceed 1,008 feet. NRC officials were at the plant at the time and NRC statements said the plant remains safe. NRC Chairman Gregory Jaczko
confirmed the plant's safety when he visited the plant on June 27.
On June 30 one of the pumps used to remove seepage caught fire when a worker was refilling it with gasoline. The worker put the fire out with a fire extinguisher but was burned on his arms and face and he was airlifted via helicopter to Lincoln, Nebraska
. OPPD said the fire was in an auxiliary security building area and not in the reactor area and that the plant was never in danger.
On July 11 OPPD installed a new 8 foot inflatable berm to replace the one that was punctured and failed on June 26.
The NRC gave the plant a "D" rating in early September 2011 due to the 2009 flood mitigation and control issues (flood preparedness) and for a faulty electrical connector issue from 2010. Though flood waters from the 2011 Missouri River flood had subsided, the plant would remain shutdown until federal regulators were convinced that OPPD had demonstrated improved compliance. The plant may still be under a "D" rating and still be allowed to operate. NRC officials were confident OPPD would be able to operate the plant safely.
Nuclear power plant
A nuclear power plant is a thermal power station in which the heat source is one or more nuclear reactors. As in a conventional thermal power station the heat is used to generate steam which drives a steam turbine connected to a generator which produces electricity.Nuclear power plants are usually...
located on 660 acres (267.1 ha) between Fort Calhoun
Fort Calhoun, Nebraska
Fort Calhoun is a city in Washington County, Nebraska, United States. The population was 856 at the 2000 census.Fort Calhoun Nuclear Generating Station is built on...
, and Blair, Nebraska
Blair, Nebraska
Blair is a city in and the county seat of Washington County, Nebraska, United States. The population was 7,990 at the 2000 census. Blair is a part of the Omaha-Council Bluffs Metropolitan Statistical Area.- History :...
adjacent to the Missouri River
Missouri River
The Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
between mile markers 645.6 and 646.0. The utility has an easement
Easement
An easement is a certain right to use the real property of another without possessing it.Easements are helpful for providing pathways across two or more pieces of property or allowing an individual to fish in a privately owned pond...
for another 580 acres (234.7 ha) which is maintained in a natural state. The power plant is owned and operated by the Omaha Public Power District
Omaha Public Power District
Omaha Public Power District, or OPPD, is a public electric utility in the State of Nebraska. It is one of the largest publicly owned electric utilities in the United States, serving more than 340,000 customers in 13 southeast Nebraska counties. OPPD was formed in 1946 as a political subdivision of...
of Omaha, Nebraska
Omaha, Nebraska
Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County. It is located in the Midwestern United States on the Missouri River, about 20 miles north of the mouth of the Platte River...
and accounts for 25 percent of OPPD's net generation capabilities.
This plant has one Combustion Engineering
Combustion Engineering
Combustion Engineering was an American engineering firm and leading firm in the development of power systems in the United States with approximately 30,000 employees in about a dozen states at its peak. Headquartered in Stamford, Connecticut, C-E owned over two dozen other companies including...
pressurized water reactor
Pressurized water reactor
Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
generating 484 megawatts of electricity. This is currently the smallest rated capacity among all operating commercial power reactors in North America, and as a single-unit plant, this also qualifies it as the smallest rated capacity nuclear power plant. OPPD's two Nebraska City
Nebraska City, Nebraska
Nebraska City is a city in Otoe County, Nebraska, United States. The population was 7,228 at the 2000 census. It is the county seat of Otoe County...
coal-fired plants at 682 (opened 2009) and 649 (opened 1979) MW are both significantly larger.
Fort Calhoun houses spent fuel rods in a 40 foot deep spent fuel pool
Spent fuel pool
Spent fuel pools are storage pools for spent fuel from nuclear reactors. They are typically 40 or more feet deep, with the bottom 14 feet equipped with storage racks designed to hold fuel assemblies removed from the reactor. A reactor's pool is specially designed for the reactor in which the...
next to the reactor, and when the pool had nearly reached capacity in 2006, OPPD began to store spent fuel rods above ground in dry cask storage
Dry cask storage
Dry cask storage is a method of storing high-level radioactive waste, such as spent nuclear fuel that has already been cooled in the spent fuel pool for at least one year.. These casks are typically steel cylinders that are either welded or bolted closed. When inside, the fuel rods are surrounded...
as well. In total, the Ft. Calhoun reactor has 600,000 to 800,000 pounds of high level nuclear waste. The storage was not designed to house spent fuel permanently, but when plans for Yucca Mountain nuclear waste repository were terminated, OPPD stated that they are "prepared to safely store material on-site as long as necessary".
The plant underwent refurbishment in 2006 by having its steam generators
Steam generator (nuclear power)
Steam generators are heat exchangers used to convert water into steam from heat produced in a nuclear reactor core. They are used in pressurized water reactors between the primary and secondary coolant loops....
, pressurizer, reactor vessel head, low pressure turbines and main transformer replaced. In 2003, the plant had its operating license renewed for an additional twenty years. With the renewal, the license for Fort Calhoun was extended from August 9, 2013, to August 9, 2033.
The 2011 Missouri River floods
2011 Missouri River floods
The 2011 Missouri River floods are a flooding event on the Missouri River in the United States. The flooding has been triggered by record snowfall in the Rocky Mountains of Montana and Wyoming along with near record spring rainfall in central and eastern Montana...
surrounded the plant with flood water, an unprecedented event for a U.S. nuclear power plant due to both the level of flooding and the anticipated period of time the flood is expected to persist.
Surrounding population
The Nuclear Regulatory CommissionNuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of about 10 miles (16.1 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80.5 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity. In 2010, the population within 10 miles of Fort Calhoun was 20,639; the population within 50 miles was 953,410. The closest major city is Omaha, with a population of 408,958, whose center is 18 miles (29 km) from the plant.
Seismic risk
The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Fort Calhoun was 1 in 76,923, according to a NRC study published in August 2010.Flooding risk
A flood assessment performed by the Nuclear Regulatory Commission in 2010 indicated that the Fort Calhoun Nuclear Generating Station, "did not have adequate procedures to protect the intake structure and auxiliary building against external flooding events." The assessment also indicated that the facility was not adequately prepared for a "worst-case" flooding scenario. A number of potential flood water penetration points were discovered that could have impacted the raw feed water supply to the cooling system, the auxiliary water supply and main switchgear (electrical) room. By early 2011, corrective measures had been implemented. In 2009 the NRC did a flood risk assessment which found that the protection measures were only designed to handle floods to 1009 feet (307.5 m) above sea level which was below the NRC mandated elevation of 1014 feet (309.1 m) for the plant. The risk assessment stated that at 1010 feet (307.8 m), flooding would have "led to a 100 percent chance of a fuel damage if the emergency gasoline pumps didn't work."Events
On June 6, 2011 the Omaha Public Power District, as required by Nuclear Regulatory Commission guidelines, declared a Notification of Unusual Event (minimal level on a 4 level taxonomy) due to flooding of the Missouri River. The Missouri River is above flood stage and is expected to rise further and remain above flood stage for several weeks to a month. Contractors have been busy installing sandbags and earthen berms to protect the facility from flooding. According to officials, the plant was built to withstand a 500 year flood100-year flood
A one-hundred-year flood is calculated to be the level of flood water expected to be equaled or exceeded every 100 years on average. The 100-year flood is more accurately referred to as the 1% annual exceedance probability flood, since it is a flood that has a 1% chance of being equaled or exceeded...
ing event and though by June 14, 2011, much of the facility was surrounded by the swollen Missouri River, Omaha Public Power District officials were confident that enough redundancies were in place to ensure adequate safety. It was reported on June 17, 2011 that the plant was in "safe cold shutdown" mode for refueling and the anticipation of flooding, and that four weeks worth of additional fuel had been brought in to power backup generators, should they be needed. The Army Corps of Engineers
United States Army Corps of Engineers
The United States Army Corps of Engineers is a federal agency and a major Army command made up of some 38,000 civilian and military personnel, making it the world's largest public engineering, design and construction management agency...
indicated that with average precipitation, the Missouri River would not go above 1008 feet (307.2 m) above sea level and OPPD officials stated that the current flood protection efforts would protect the plant to 1010–1012 ft (307.8–308.5 ) feet above sea level. Officials indicated the spent fuel pool is at 1038.5 feet (316.5 m) above sea level.
On June 7, 2011, an electrical component in a switch gear room caused a small fire with Halon extinguisher activation which forced a partial evacuation. The fire was no longer burning when the on site fire brigade arrived and according to officials, the public was never in any danger. The fire impacted pumping of coolant water through the spent fuel pool. Cooling was interrupted for 90 minutes while the estimated time for the pool to reach boiling temperature was over 88 hours. In response, the Omaha Public Power District declared an alert (second level on a 4 level taxonomy). The evacuation was the first at the facility since 1992, when 20000 gallons (75,708.2 l) (ca. 76 t
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
) of coolant leaked into a containment building from the reactor.
On June 23 a helicopter contracted by OPPD to survey transmission lines made an unplanned landing 1.5 miles south of the plant. Reports described it as an unplanned landing although photographs showed it on its side in a field. Nobody was injured. The Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
had declared a "temporary flight restriction," in a two nautical mile radius, centered on the Fort Calhoun nuclear facility. This restriction went into effect on June 6, 2011, at 4:31 PM, and remains in effect "until further notice." Officials noted that the June 6 FAA directive was actually a reminder to a standing order creating no flight zones over all U.S. nuclear power plants which had been in effect after the 2001 9/11 attacks.
On June 26, at 1:30 a.m., a 8 feet (2.4 m) high, 2000 feet (609.6 m) long water filled rubber flood berm surrounding portions of the plant, was punctured by a small earth mover ("Bobcat") and collapsed. The collapse of the flood berm allowed flood waters to surround the auxiliary and containment buildings at the plant, and also forced the temporary transfer of power from the external electricity grid to backup electrical generators. It was reported more than 2 foot (0.6096 m) of water rushed in around buildings and electrical transformers. Backup generators were then used to ensure the facility maintained electrical power for cooling. The rupturing of the flood berm also resulted in approximately 100 gallons (378.5 l) of petroleum being released into the river as many fuel containers were washed out. The fuel/oil containers were staged around the facility to supply fuel for pumps which remove water within the flood containment barriers. The rubber berm was a secondary measure not mandated by the NRC and was put in place by OPPD to provide additional room for work immediately outside the reactor buildings. According the NRC, the water-filled berm "protects several pieces of equipment that have been brought onsite, including an additional emergency diesel generator for supplying AC electrical power, water pumps, firefighting equipment and sandbagging supplies".
According to OPPD, the plant is designed to withstand waters up to 1,014 feet above mean sea level. The river is not expected to exceed 1,008 feet. NRC officials were at the plant at the time and NRC statements said the plant remains safe. NRC Chairman Gregory Jaczko
Gregory Jaczko
Gregory B. Jaczko is the Chairman of the U.S. Nuclear Regulatory Commission .-Early life and education:Jaczko was raised in Albany, New York. He studied physics and philosophy at Cornell University in Ithaca, New York, and earned a bachelor in the two disciplines, there, in 1993...
confirmed the plant's safety when he visited the plant on June 27.
On June 30 one of the pumps used to remove seepage caught fire when a worker was refilling it with gasoline. The worker put the fire out with a fire extinguisher but was burned on his arms and face and he was airlifted via helicopter to Lincoln, Nebraska
Lincoln, Nebraska
The City of Lincoln is the capital and the second-most populous city of the US state of Nebraska. Lincoln is also the county seat of Lancaster County and the home of the University of Nebraska. Lincoln's 2010 Census population was 258,379....
. OPPD said the fire was in an auxiliary security building area and not in the reactor area and that the plant was never in danger.
On July 11 OPPD installed a new 8 foot inflatable berm to replace the one that was punctured and failed on June 26.
The NRC gave the plant a "D" rating in early September 2011 due to the 2009 flood mitigation and control issues (flood preparedness) and for a faulty electrical connector issue from 2010. Though flood waters from the 2011 Missouri River flood had subsided, the plant would remain shutdown until federal regulators were convinced that OPPD had demonstrated improved compliance. The plant may still be under a "D" rating and still be allowed to operate. NRC officials were confident OPPD would be able to operate the plant safely.