Fort Calhoun Nuclear Station
Operator: Omaha Public Power District
Location: 19 Miles North of Omaha, NE
Fort Calhoun Nuclear Station
9610 Power Lane
Blair, NE 68008
Operating License Unit 1: Issued – August 9, 1973, Expires – August 9, 2033
Reactor Type: Pressurized Water Reactor (PWR)
Electrical Output Unit 1: 500 Megawatts Electrical (MWe)
Fort Calhoun Station (FCS) is a Pressurized Water Reactor (PWR) and generates about 35% of the retail energy produced by the Omaha Public Power District (OPPD). The plant is located on a 660 acre site along the west bank of the Missouri River between the cities of Blair and Fort Calhoun approximately 19 miles north of Omaha, Nebraska. The plant originally broke ground for construction in 1968, began initial fuel loading in 1973 and reached initial criticality at 5:47 P.M. on August 5, 1973. The plant reached full power output for the first time on May 4, 1974. A slight power up-rate from 1420 MW Thermal to 1500 MW Thermal was approved on August 15, 1980. In 2003, OPPD received an operating license extension from the U.S. Nuclear Regulatory Commission which extended the current operating license from 2013 through 2033. The unit is in the process of upgrading several key components to gain an additional 75-80 MW Electric by the end of 2012.
• Nebraska is the only state in the United States which mandates public ownership of the state’s electricity industry. Fort Calhoun Station is owned and operated by the Omaha Public Power District and has a publicly elected Board of Directors.
• As of 2009, OPPD had a total generating capability of 3,224 megawatts and approximately 2400 employees serving 343,200 electric customers.
• OPPD rates rank well below (24.1% to 32.5%) the national average and is the 12th-largest public power utility in the United States.
• OPPD serves 47 towns at retail and five at wholesale in a 5,000 square-mile service area in 13 Nebraska counties.
• OPPD (Fort Calhoun Station) was one of the seven original founders of the Utilities Service Alliance.
• The plant’s single generating unit has a capacity of about 500 megawatts, enough energy to power approximately 420,000 homes.
• In a pressurized water reactor, such as FCS; the controlled fissioning of uranium atoms in the reactor core generates heat which is carried by the reactor coolant system (very pure water) through U-tubes in two steam generators, which transfer the heat to a secondary water system in the secondary side of the plant. The cooled reactor coolant is then pumped back into the reactor to complete the primary loop and again pick up heat from the fission process. The secondary system water turns to steam on the outside of the tubes in the steam generators and then passes through a series of steam turbines connected to a large generator. The exhausted steam is then cooled back into water in the plant’s main condenser and pumped back into the steam generators to complete the secondary loop. The cooling loop is Missouri River water which is pumped through tubes in the main condenser to pick up heat from the secondary system on the outside of the tubes and then is returned to the river. All three basic water systems never touch each other. All heat transfer is completed through a series of tubes in the steam generators or the main condenser.
• The plant’s reactor core holds 133 fuel assemblies. Each assembly consists of a matrix of fuel rods with a composition of natural, depleted, or slightly enriched uranium dioxide (UO2) material. Reactor control is accomplished with a system of 49 control element assemblies (CEA’s) which are made of materials that “absorb” neutrons and can easily stop the fission process in the reactor. Along with the CEA’s, reactivity is also controlled by use of a boron solution added to the primary coolant system. Boron is also a “neutron absorber.”
• The primary coolant system and reactor were designed by Combustion Engineering and is comprised of two “E-Loops” and two steam generators (one per loop). The “E-Loops” have one hot leg (water coming from the reactor to the steam generator) and two cold legs, each with a reactor coolant pump for circulation (water returning from the steam generators to the reactor).
• The Pressurized Water Reactor normally operates at a controlled pressure of approximate 2100 pounds per square inch absolute. The pressure control is maintained by a Pressurizer which is a controlled volume tank connected to the primary coolant loop and has a series of heaters (to increase pressure, when needed) and a water spray system (to decrease pressure, when needed).
• The entire reactor and primary coolant system is enclosed in a reactor containment structure. The containment structure provides a highly reliable, essentially leak-tight barrier against the escape of radioactivity to the environment should a failure of the reactor coolant system occur. The cylindrical, domed structure is constructed of post-tensioned concrete with a continuous carbon steel liner.
• The reactor is shutdown approximately every 18 months for refueling and maintenance of major components. During a typical refueling, about one-third of the 133 fuel assemblies are replaced. A typical fuel assembly is used for a total time period of approximately 54 months or 4½ years.
Plant Operational Facts
• The station runs essentially 24 hours a day, seven days a week, except during refueling or emergent maintenance outages. The unit is considered a base-load plant and operated at essentially 100% reactor power during normal operations.
• Cost of the initial plant construction was only $178M (land and plant).
• The first electricity generated at FCS and supplied to the transmission system occurred on August 25, 1973.
• The plant began commercial operation, generating 180,000 KWH on September 26, 1973.
• The plant set a world record in 1988 for continuous operation of 477 days.
• The plant set another record “breaker to breaker” run of 483 days in 1998-99.
• The shortest refueling outage to date at the site was completed on June 3, 2002 and lasted 29.1 days.
Used Fuel Storage
• Initially upon removal from the reactor, used fuel is stored in a pool inside of the plant until it has cooled sufficiently to be safely stored in an air cooled Independent Spent Fuel Storage Installation (ISFSI).
• The spent fuel pool is a reinforced concrete structure lined with stainless steel and has the capacity to hold 1083 fuel assemblies. The pool is full of boronated water and is cooled by a separate cooling and purification system to maintain normal water temperatures below 120°F.
• After assemblies have sufficiently been cooled and decay heat generation is minimized, the assemblies are then loaded into stainless steel canisters which hold a total of 32 spent fuel assemblies each. The canisters are then drained, vacuum dried and filled with an inert gas after seal welding redundant lids onto the top of the canisters.
• By use of an engineered cask transfer system, the canisters are then placed horizontally into concrete horizontal storage modules located within the protected area of the station, with concrete shield walls, concrete approach slabs, all built on an elevated basemat.
• The site is built to hold up to forty of the horizontal storage modules in rows of 20 each, back-to-back.
Go to www.oppd.com and click on the “About Us” tab, then select the “Speaker’s Bureau” for directions on how to schedule a speaker and presentation.