Calvert Cliffs Nuclear Power Plant

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Calvert Cliffs Nuclear Power Plant
The Calvert Cliffs Nuclear Power Plant (CCNPP) is a nuclear power plant located on the western shore of the Chesapeake Bay near Lusby, Calvert County, Maryland.

The plant, owned and operated by Constellation Energy, has two 2700 megawatt thermal (MWth) Combustion Engineering Generation II, two loop pressurized water reactors. Each generating plant (CCNPP 1&2) produces approximately 850 megawatt electrical (MWe) net or 900 MWe gross. Each plant's electrical load consumes approximately 50 MWe. These are saturated steam plants (non-superheated) and are approximately 33% efficient (ratio of 900 MWe gross/2700 MWth core). Only the exhaust of the single High Pressure Main Turbine is slightly superheated by a two stage reheater before delivering the superheated steam in parallel to the three Low Pressure Turbines. Unit 1 uses a General Electric designed main turbine and generator, while Unit 2 uses a Westinghouse designed main turbine and generator. The heat produced by the reactor is returned to the bay, which operates as a cooling heat-sink for the plant. Unit 1 went into commercial service in 1975 and Unit 2 in 1977. The total cost of the two units was approximately 766 million USD. Unit 1 had its two steam generators replaced in 2002 and its reactor vessel closure head replaced in 2006, while unit 2 had its two steam generators replaced in 2003, and its vessel closure head replaced in 2007. The water around the plant (see lower-right-center of photograph) is a very popular place for anglers. Unit 1 & 2 each takes in bay water (from the fenced-in area) to cool its steam driven turbine condensers plus other bay water cooled primary and secondary system heat exchangers. The bay water is pumped out at a nominal flow rate of 1.2 million gallons per minute (75,000 L/s) per unit (Unit 1 and 2) for each steam turbine condenser. The water is returned to the bay no more than 12 °F (6.7 °C) warmer than the bay water. Unlike many other nuclear power plants, Calvert Cliffs did not have to utilize water cooling towers to return the hot water to its original temperature. As the water comes out very quickly and creates a sort of artificial rip current, it can be a dangerous place to fish. CCNPP 3 will only need about 10% of the bay cooling water volume needed for Unit 1 and 2 combined. The increase in fish and shellfish impingement and entrainment will be less than 3.5% over Unit 1 and 2 existing conditions. In February 2009, Calvert Cliffs set a world record for Pressurized Water Reactors (PWRs) by operating 692 days non-stop. (US-EPR), Generation III+ In addition, Unit 2's capacity factor in 2008 was a world-record high of 101.37 percent.

2000 renewal of operating license
In 2000, the Nuclear Regulatory Commission extended the license of the plant for 20 additional years, making Calvert Cliffs the first nuclear plant in the United States to receive such an extension. President George W. Bush visited the plant in June 2005, the first time a president had visited a nuclear power plant in nearly two decades.

Proposal to add a third reactor
UniStar Nuclear Energy announced it will probably build a new advanced US-Evolutionary Power Reactor (US-EPR) at this site. UniStar Nuclear Energy, a Delaware limited liability company, is jointly owned by Constellation Energy (CEG) and Électricité de France (EdF), a builder and supplier of nuclear power plants in Europe. This proposed single nuclear unit will produce approximately twice the energy of each individual existing plant. See Nuclear Power 2010 Program. On July 13, 2007, UniStar Nuclear Energy filed a partial application to the Nuclear Regulatory Commission to review its plans to build a new nuclear power plant, Calvert Cliffs Nuclear Power Plant 3 (CCNPP 3) based on the AREVA U.S. Evolutionary Power Reactor (US-EPR), Generation III+, four loop pressurized water reactor. The remainder of the license application was submitted to the NRC in March 2008. The NRC confirmed its acceptance for technical review in June 2008. The CCNPP 3 reactor will be rated at 4590 MW thermal/1710 MW electrical gross. Plant loads will be approximately 110 Mwe, thus the net generation is 1600 MWe. Plant thermal efficiency will be approximately 36% (ratio of 1710 MWe to 4590 MWth). A final decision by Constellation to start construction is expected by the end of 2009, paving the way for pre-construction activities. This third reactor will help address the need for more baseload, generating power in the Mid-Atlantic region. The plant will be located south of the existing CCNPP 1&2 and will be set back from the shoreline. Although only a single unit, its power plant footprint will be almost 2 times the size of the twin units CCNPP 1&2. It will have a closed-loop cooling system using a single hybrid mechanical draft cooling tower. It will incorporate plume abatement (no visible water vapor plume). Units 1&2 use an open-cycle heat dissipation system (no cooling towers). Two thirds of the heat produced by the Unit 3 reactor will be released to the atmosphere via the cooling tower. This also is a saturated steam plant with a Main Steam Turbine (one high pressure turbine in tandem with three low pressure turbines) and a Main Generator design similar to Unit 1 & 2. ALSTOM will supply the Main Steam Turbine and Main Generator. Units 1 and 2 and their support facilities use a well water system for their potable water supply. It consists of five wells that pump water from the second highest aquifer, the Aquia Aquifer, at the minus 400”“500 foot below sea level elevation. The State of Maryland limits daily usage for these five wells to 450,000 gallons per day (gpd). Actual daily usage averages 225,000 gpd. Unlike units 1 and 2, Unit 3 will have a desalination plant to produce potable water using reverse osmosis. The desalination plant will produce up to 1,250,000 gallon of potable water per day for Unit 3 and supporting facilities with total dissolved solids (TDS) less than 400 parts per million (ppm). The source for the desalination plant will be the brackish bay water from the makeup supply to the circulating water system. The TDS for the brackish bay water runs 10,000-15,000 ppm. The potable water will be distributed as makeup water for the demineralized water system, miscellaneous potable water services, fire protection and source water for the four ultimate heatsink cooling towers used during normal shutdown and power operation. On November 13, 2007, UniStar Nuclear Energy filed an application for a certificate of public convenience and necessity with the Maryland Public Service Commission for authority to construct CCNPP 3. This application is being considered in Case Number 9127. Opponents and supporters of the proposed third reactor at Calvert Cliffs have been involved in a series of public hearings before officials of the U.S. Nuclear Regulatory Commission. In March 2009, Bill Peil of southern Calvert County asked the Nuclear Regulatory Commission to deny an emissions permit for the reactor due to health and safety concerns he maintains the plant poses to the community. UniStar Nuclear Energy President and CEO George Vanderheyden urged the NRC to approve the air permit application. In October 2010, Constellation Energy said that it had reached an impasse in negotiations for a federal loan guarantee to build the proposed third nuclear reactor at Calvert Cliffs. The government was seeking a fee of $880 million on a guarantee of about $7.6 billion, to compensate taxpayers for the risk of default. However, Constellation Energy has said that fee would doom the project, “or the economics of any nuclear project, for that matter”.

Environmental concerns
Scientists at Johns Hopkins University became concerned that the discharge of heated cooling water from the plant would be detrimental to a crucial element of the Chesapeake Bay ecosystem, the bay's famed blue crabs. In the late 1960s, litigation borne of Congress's National Environmental Policy Act eventually spawned one of the most celebrated environmental cases in American history, Calvert Cliffs Coordinating Council v. Atomic Energy Commission, forcing the Atomic Agency Commission to consider the environmental impact of building and maintaining such an atomic energy plant.

Building Activity

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