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Entergy reduces Massachusetts Pilgrim reactor to clean condenser

March 19 (Reuters) - Entergy Corp reduced the 685-megawatt Pilgrim nuclear power plant in Massachusetts early Wednesday to clean the condenser, the U.S. Nuclear Regulatory Commission said in an email.

Electricity traders said the unit was reduced to about half power early Wednesday from full power earlier in the day.

The NRC said the company cleans the condenser on a semi-regular basis to reduce the buildup of biological material, such as algae.

Traders estimated the unit would return to full power in a day or so.

---------------------------------------------------------- PLANT BACKGROUND/TIMELINE STATE: Massachusetts COUNTY: Plymouth TOWN: Plymouth OPERATOR: Entergy OWNER(S): Entergy UNIT(S): 685 MW Nuclear FUEL: Nuclear DISPATCH: Baseload COST: $462.25 million in 2007 US dollars TIMELINE: 1972 - Pilgrim enters service 2006 - Entergy files with NRC to renew the original 40-year operating license for an additional 20 years 2012 - NRC renews reactor license 2032 - License expires (Reporting by Scott DiSavino)