A California commission yesterday indicated it is likely to investigate a shuttered nuclear plant in San Diego County, a probe that will include a look at whether the facility should ever reopen.

The California Public Utilities Commission (CPUC) issued a draft order launching an inquiry into the San Onofre Nuclear Generating Station, which closed Jan. 31 after the escape of a small amount of radiation from a steam generator tube.

The CPUC will vote Oct. 25 on whether to open a formal inquiry. The commission's draft order signaled that regulators, if they go forward, will take a comprehensive look at the plant, known as SONGS.

"This investigation will consider the causes of the outages, the utilities' responses, the future of the SONGS units, and the resulting effects on the provision of safe and reliable electric service at just and reasonable rates," the order said.

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.

Plant operator Southern California Edison Co. said that it would "cooperate with the commission if an investigation regarding extended outages at the San Onofre plant is started."

Edison said that it has "provided regular updates to CPUC commissioners and staff" since the Unit 3 steam generator was taken offline Jan. 31. The Unit 2 generator was removed from service Jan. 9 for a planned outage and was not restarted because of a federal investigation.

An environmental group consultant praised the CPUC's decision.

"This is kind of a landmark decision by the PUC, to use their regulatory power to do their job," said David Freeman, a consultant for Friends of the Earth and former general manager at the Los Angeles Department of Water and Power.

"The whole future of San Onofre is now going to be on the table," Freeman added. "People will have a chance to make their case" in an open hearing.

The CPUC's decision takes place as the Nuclear Regulatory Commission considers whether to allow Edison to restart Unit 2. The utility filed paperwork seeking to run that generator at 70 percent capacity, saying that would prevent the conditions that caused the generators to vibrate, leading to wear on tubes carrying radioactive fluid. Tube degradation in the Unit 3 generator allowed the radiation leak.

NRC has said it does not have a deadline for making a decision on Edison's request. It also is considering whether to require the utility to go through a more formal, open proceeding with courtroom-style questioning. Friends of the Earth and the Natural Resources Defense Council have filed requests that NRC order a license amendment, which would launch public hearings.

The CPUC probe, if approved, would examine a number of issues including whether customers of plant owners Edison and San Diego Gas and Electric Co. should win a rate cut. Charges related to San Onofre could be removed from power rates and customers would receive refunds for SONGS-related costs already collected going back to Jan. 1, 2012.

San Onofre costs included in rates are about $1.1 billion annually, the CPUC said.

For the utility to collect those, the plant is supposed to be "used and useful," the CPUC's Division of Ratepayer Advocate said in August when it urged regulators to cut rates.

"The commission already has ample evidence that SONGS Unit 2 will not be online anytime soon and Unit 3 may never return to service," DRA said in a letter to CPUC commissioners.

In addition, there's the issue of the $650 million that Edison spent on the steam generators, which were installed as replacements in 2010 and 2011. They were supposed to last 40 years.

Regulators also could challenge whether Edison and SDG&E made reasonable purchases of "energy, capacity and other related services" to replace the power San Onofre would have generated.

The CPUC also is likely to assess:

• The cost-effectiveness of options for repairing or replacing one or both units of the steam generators.

• Any additional San Onofre issues that could affect electricity rates, including the availability of insurance or warranty coverage for any of the costs related to the San Onofre outage

• The "reasonableness and necessity of each SONGS-related operation and maintenance expense, and capital expenditure made, on and after January 1, 2012, reviewed within the context of the facts and circumstances of the extended outages of Units 2 and 3."