Calvert Cliffs Nuclear Power Plant
| Company type | Nuclear power plant |
|---|---|
| Industry | Energy |
| Founded | 1975 |
| Founder | Constellation Energy |
| Headquarters | Lusby, Calvert County , United States |
Area served | Mid-Atlantic United States |
| Products | Electricity generation (nuclear) |
| Owner | Constellation Energy (now part of Exelon) |
The Calvert Cliffs Nuclear Power Plant (CCNPP) is a nuclear power plant situated on the western shore of the Chesapeake Bay near Lusby in Calvert County, Maryland, within the Mid-Atlantic United States. It stands as the sole nuclear energy facility in the state of Maryland.
Overview
Operated and owned by Constellation Energy, this facility comprises two 2737 MW thermal (MWth) Combustion Engineering Generation II two-loop pressurized water reactor units. Each reactor (CCNPP Units 1 and 2) generates approximately 850 megawatts electrical (MWe) net output, or about 900 MWe gross, with roughly 50 MWe utilized internally. These plants produce saturated steam and achieve an efficiency close to 33% (900 MWe gross from a 2700 MWth core). The exhaust steam from the single high-pressure main turbine undergoes slight superheating through a two-stage reheater before powering three low-pressure turbines. Unit 1 features turbine and generator equipment designed by General Electric, while Unit 2 employs Westinghouse technology. The heat generated by the reactors is released into the bay, which serves as the cooling medium.
Unit 1 commenced commercial operation in 1975, followed by Unit 2 in 1977. The total construction expenditure was approximately $766 million, equivalent to nearly $2 billion when adjusted for inflation. This plant played a pivotal role in a landmark legal case in 1971 that set precedents for regulatory agencies to conduct environmental impact assessments proactively.
Significant modernization efforts include replacing Unit 1’s steam generators in 2002 and its reactor vessel closure head in 2006; Unit 2 underwent similar replacements in 2003 and 2007 respectively.
Each reactor unit draws about 1.2 million gallons per minute of water from the bay to cool steam turbine condensers and other heat exchangers, discharging water back into the bay at no more than a 12 °F increase in temperature. Unlike many nuclear plants that utilize cooling towers, Calvert Cliffs relies exclusively on direct bay water cooling, which produces strong currents that affect local fishing activities. The proposed addition of CCNPP Unit 3 is expected to require only about one-tenth of the current cooling water volume, resulting in minimal further environmental impact.
In February 2009, Calvert Cliffs set a global record among pressurized water reactors when Unit 2 operated continuously for an unprecedented 692 days. Additionally, Unit 2 achieved an exceptional capacity factor of 101.37% during the year 2008.
Electricity production
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Total Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2001 | 1,293,872 | 1,168,618 | 963,457 | 623,493 | 938,578 | 1,202,772 | 1,252,634 | 1,245,846 | 1,212,574 | 1,223,040 | 1,244,048 | 1,287,335 | 13,656,267 |
| 2002 | 1,288,202 | 862,457 | 645,092 | 619,921 | 639,467 | 829,551 | 1,146,622 | 1,242,220 | 1,211,273 | 1,271,399 | 1,079,479 | 1,292,322 | 12,128,005 |
| 2003 | 1,292,663 | 872,233 | 647,476 | 784,844 | 1,259,096 | 1,240,051 | 1,270,234 | 1,258,254 | 1,226,338 | 1,293,673 | 1,245,064 | 1,300,787 | 13,690,713 |
| 2004 | 1,245,680 | 1,218,948 | 1,261,451 | 816,454 | 1,104,627 | 1,250,809 | 1,278,968 | 1,272,708 | 1,231,056 | 1,301,634 | 1,274 ,705 </ small > | < small > 1323220 </ small > | 14 ,580 ,260 |
| 2005 | < small > 1322990 </ small > | < small >1047379 </ small > | < small >949726 </ small > | < small >1267648 </ small > | < small >1307731 </ small > | < small >1240130 </ small > | < small >1254931 </ small > | < small >1252361 </ small > | < small >1218377 </ small > | < small >1283417 </ small > | < small >1249369 </ small > | < small >1309162 </ small > | 14 ,703 ,221 |
| 2006 | < small >1296648 </ small > | < small >992845 </ small > | < small >648193 </ small > | < small >1014558 </ small > | < small >1303841 </ small > | < small >1246405 </ small > | < small >1264266 </ small > | < small >1258643 </ small > | < small >1233168 </ small > | < small >1287865 </ small > | < small >1153244 </ small > | < small >1130735 </ small > | 13 ,830 ,411 |
| 2007 | < small >1297997 </ small > | < small >1086076 </ small > | < small >661313 </ small > | < small >1182021 </ small > | < small >1303229 </ small > | < small >1241232 </ small > | < small >1266519 </ small > | < small >1251396 </ small > | < small >1223218 </ small > | < small >1264543 </ small > | < small >1262781 </ small > | < small >1312867 </ small > | 14 ,353 ,192 |
| 2008 | < small >1315326 </ small > | < small >1069745 </ small > | < small >976840 </ small > | < small >1262420 </ small > | < small >1292113 </ small > | < small >1231842 </ small > | < small >1242086 </ small > | < small >1235296 </ small > | < small >1213153 </.small> | <.small>1273123</.small> | <.small>1261192</.small> | <.small>1305559</smal l > | 14 ,678 ,695 |
| 2009 | 1303777 | 1045223 | 940839 | 1260328 | 1291934 | 1226644 | 1158547 | 1245982 | 1225916 | 1282637 | 1259342 | 1308950 | 14 ,550 ,119 |
2010
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Surrounding population
The Nuclear Regulatory Commission (NRC) establishes two distinct emergency planning zones around nuclear facilities: a 10-mile plume exposure pathway zone that focuses on airborne radioactive hazards, and a 50-mile ingestion pathway zone which addresses the risk of contaminated food and beverages.
As of 2010, the number of residents living within a 10-mile radius of Calvert Cliffs was 48,798, representing an increase of 86.4% since 2000. Within the broader 50-mile zone, the population totaled 2,890,702, reflecting a 2.0% decline from the year 2000. Notable urban centers in this range include Washington, D.C., situated approximately 45 miles away.
Proximity to LNG plant
In 2001, local community members expressed apprehensions regarding the reopening of the Dominion Cove Point LNG facility located merely three miles from the nuclear site. Critics contended that the Federal Energy Regulatory Commission had inadequately evaluated potential threats stemming from explosions or deliberate attacks prior to granting operational approval.
Seismic risk
A 2010 NRC assessment determined the likelihood of an earthquake causing core damage at Calvert Cliffs to be minimal, estimating an annual risk of about 1 in 100,000 for Reactor 1 and approximately 1 in 83,333 for Reactor 2.
Environmental concerns
During the 1960s, researchers at Johns Hopkins University voiced worries that thermal discharge from the plant’s cooling system could negatively impact the Chesapeake Bay ecosystem, particularly affecting blue crab populations. Legal action under the National Environmental Policy Act of 1970 culminated in a 1971 ruling by the U.S. Court of Appeals mandating that the Atomic Energy Commission (the NRC’s predecessor) conduct environmental impact evaluations related to the plant’s construction and operation.
2000 renewal of operating license
In the year 2000, Calvert Cliffs became the first nuclear power station in the United States to receive a 20-year extension on its operating license from the NRC. In 2005, President George W. Bush visited the facility, marking the first presidential visit to a nuclear power plant in nearly two decades.
Proposal to add a third reactor
UniStar Nuclear Energy—a partnership between Constellation Energy (CEG) and Électricité de France (EDF)—proposed constructing a third reactor unit at Calvert Cliffs utilizing AREVA’s Generation III+ US Evolutionary Power Reactor (US-EPR) design. This new unit was intended to generate approximately twice the output of each existing reactor and was planned for a location south of units 1 and 2. The design included a larger site footprint and featured a closed-loop cooling system with a hybrid mechanical draft cooling tower equipped with plume abatement technology.
On July 13, 2007, UniStar submitted a partial application to the NRC for review concerning Calvert Cliffs Nuclear Power Plant Unit 3 (CCNPP 3). The initiative aimed to address increasing baseload electricity demand in the Mid-Atlantic region. Alstom was contracted to provide the main steam turbine and generator equipment.
In November 2007, UniStar sought a certificate of public convenience and necessity from the Maryland Public Service Commission. Public hearings revealed opposition driven by health and safety concerns, while UniStar’s CEO advocated strongly for project approval.
By October 2010, Constellation Energy discontinued negotiations over a federal loan guarantee due to an $880 million proposed fee on a $7.6 billion guarantee, which they argued would adversely affect project viability. Subsequently, in November 2010, Constellation sold its entire 50% interest in UniStar to EDF for $140 million, transferring full ownership along with corresponding board changes.
In April 2011, the NRC determined UniStar was no longer eligible to construct the reactor because it ceased to be U.S.-owned after Constellation’s withdrawal; licensing would require compliance with ownership regulations. The projected cost stood at $9.6 billion. Constellation merged into Exelon in 2012.
In 2015, AREVA withdrew from certifying the US-EPR design amid corporate restructuring efforts, effectively halting plans to deploy this European reactor model within the United States and resulting in withdrawal of Calvert Cliffs Unit 3’s combined license application.
Incidents
On September 5, 2013, Unit 2 at the Calvert Cliffs nuclear facility was taken offline following a testing-related malfunction. After completing necessary repairs, the unit recommenced operations on September 10, 2013.
Reactor data
The Calvert Cliffs Nuclear Power Plant currently operates two reactors. Although a third reactor was proposed in 2007, the plan was subsequently abandoned.
| Reactor unit | Reactor type | Capacity (MW) | Construction start date | Grid connection date | Commercial operation date | Decommissioning date | |
|---|---|---|---|---|---|---|---|
| Net | Gross | ||||||
| Calvert Cliffs-1 | CE 2-loop | 855 | 918 | 06/01/1968 | 01/03/1975 | 05/08/1975 | |
| Calvert Cliffs-2 | 850 | 911 | 06/01/1968 | 12/07/1976 | 04/01/1977 | ||
| Calvert Cliffs-3 (proposed) | US-EPR | 1600 | ? | ||||
See also