The plant located on the coastline in San Diego County has been idled for more than 10 months following the discovery of unexpected wear on tubes carrying radioactive water.
Edison has proposed to restart one of the plant's two reactors at 70 percent power, saying running the unit at the reduced level is safe as it would alleviate the conditions that led to the wear on the tubes, the Los Angeles Times reported Tuesday.
During a meeting Tuesday in Maryland between Edison officials and regulators with the Nuclear Regulatory Commission, NRC experts expressed concerns about the safety of some tubes that were taken out of service and plugged, if the plant is re-opened.
Some of them "are adjacent to a retainer bar that vibrates, and this vibration was the cause of wear in some tubes," NRC senior materials engineer Emmett Murphy said.
He expressed concern that resuming operations could mean the plugged tubes could wear through and break, damaging still more tubes.
Edison officials said they would answer those concerns in a response to the commission by mid-January, ahead of another meeting between the company and the NRC set for February.
A tentative NRC timeline indicates March is the earliest the agency could decide whether to approve Edison's plan.