WINTERSBURG, Ariz. (AP) -- Engineers at the Palo Verde Nuclear Generating Station 50 miles west of Phoenix have cut output from one of the plant's three reactors because of a problem with a valve.
Arizona Public Service spokesman Jim McDonald says operators discovered the problem with a steam valve Wednesday evening.
The plant's Unit 1 reactor was running at 60 percent Thursday. McDonald says it may take several days for the problem to be repaired.
Engineers are already working to fix a tiny leak in the reactor vessel at the plant's Unit 3 that was discovered after the reactor was shut down for refueling on Oct. 5. That unit isn't expected to be back online until next month.
Palo Verde supplies electricity to about 4 million customers in Arizona, New Mexico, Texas and California.