The Nuclear Regulatory Commission expects to decide as soon as March whether to allow Southern California Edison to restart a nuclear plant that has been down for nearly a year due to a leak of radioactive steam.

The NRC plans to issue a notice of intent by March, with a decision to come within 30 days of that, the agency said before a meeting yesterday on the utility's request to restart the San Onofre Nuclear Generating Station's Unit 2. Edison has proposed running the 1,070-megawatt unit at 70 percent power for five months and then shutting it down for an inspection.

Both Units 2 and 3, which produce 2,200 megawatts of electricity combined, have been shuttered since January, when plant operators discovered a small amount of radiation leaking from a steam generator tube in Unit 3. Problems were subsequently found in Unit 2, as well. There is no timeline to restart Unit 3.

At yesterday's meeting at NRC headquarters in Maryland, agency officials questioned Edison's executives closely on their plan and several third-party analyses of the steam generators. They said they might have more questions before making their decision. Another public meeting is scheduled for mid-February in Southern California. The timeline for a decision could change, an NRC spokesman said.

Utility officials said that running Unit 2 at 70 percent power should eliminate vibrations causing "tube-to-tube wear" -- the type of degradation that caused reactor coolant to leak into the steam generator in Unit 3 (Greenwire, Oct. 4).

Agency staff asked Edison executives to explain technical assumptions underlying their plan, including how long it took the tubes to wear against each other to the point of damage. "We know that Unit 3 experienced an instability and consequential damage," said Emmett Murphy, an NRC engineer. "What is not obvious is the time interval." Utility officials said they would attempt to define when the instability started.

Environmentalists are skeptical, saying the utility has not gotten to the bottom of the issues behind the tubes' degradation.

"We are approaching the first anniversary of this nuclear plant having sprung a radioactive leak, and they haven't figured out what's wrong with it," said David Freeman, a consultant for Friends of the Earth and former general manager at the Los Angeles Department of Water and Power. "They have a proposal to start half the plant up at 70 percent speed without having repaired what was broken -- or even having a clear picture of the fact that 70 percent might make any difference."

On Monday, Edison officials asked California regulators to allow them to continue charging customers for costs related to the plant's operations, citing the pending NRC decision. In their filing with the California Public Utilities Commission, they proposed keeping $176 million of the $739 million that regulators had already authorized Edison to collect on the plant in 2012.

The CPUC by law must examine the need for any plant that has been offline for more than nine months. It has the ability to declare the plant -- which provided power to 1.4 million households -- no longer financially viable (Greenwire, Oct. 17). The commission's investigation is expected to continue until 2014.

"It is not in SCE's customers' best interest to precipitously make a decision to adjust rates now before all of the facts surrounding the status of the units are known," the utility said. "While the NRC considers SCE's plan for restarting Unit 2, SCE must maintain a staff in readiness to respond to the NRC's questions and to operate Unit 2 when the NRC approves SCE's restart of Unit 2 safely."

Edison will cut the plant's staff by 750 employees, from 2,250 to 1,500, officials said in Monday's filing. They had previously estimated 500 layoffs, "but after further consideration of staffing needs for [the San Onofre plant], SCE is now planning for a downsizing of approximately 750 personnel." The first 30 employees are being laid off this month, a utility spokeswoman said.

Utility employees are challenging that plan, saying the CPUC should prevent layoffs while it considers what to do with the plant. "These workers are the very employees who will be necessary for the safe restart and operation of the units if they come back on line," a group of unions called the Coalition of California Utility Employees wrote in a filing earlier this month.