UPDATE 1-PG&E Calif Diablo Canyon reactor cut to 50 pct

(Adds reason for reduced output)

HOUSTON Oct 15 (Reuters) - PG&E Corp's (PCG.N) 1,122-megawatt Diablo Canyon 1 nuclear power unit in California was reduced to 50 percent output on Thursday to clean debris from the cooling water system, a plant spokeswoman said on Thursday.

Tuesday's storm that crossed the California coast pushed kelp and debris into the station's cooling water system, the spokeswoman said, prompting operators to move up a scheduled condenser cleaning.

The curtailment is is expected to be short, she said, but declined to give a specific timeline.

Diablo Canyon 2, rated at 1,118-MW, shut in early October for an expected month-long refueling outage.

The station is located in Avila Beach, in San Luis Obispo County, about 195 miles northwest of Los Angeles.

One MW powers about 700 homes in California.

PG&E, of San Francisco, owns and operates more than 6,200 MW of generating capacity, markets energy commodities, and transmits and distributes electricity to almost 5.3 million customers and natural gas to 4.2 million customers in California. (Reporting by Eileen O'Grady; Editing by Steve Orlofsky)