Reopening a damaged nuclear plant in Southern California without an open federal review would put millions of people at risk, some who live near the facility charged yesterday.

Nearly 900 people packed a Dana Point hotel ballroom to lobby Nuclear Regulatory Commission representatives as that agency evaluates the future of the San Onofre Nuclear Generating Station. The plant has been closed since a Jan. 31 radiation leak.

NRC Regional Administrator Elmo Collins told the crowd that the agency will not allow San Onofre to reopen unless it's safe.

That failed to appease many who called for NRC to order a public vetting of utility Southern California Edison's restart bid. They urged a license amendment, which would launch hearings featuring cross-examination from independent experts.

"I'm a scientist," said Donald Mosier, a physician and Del Mar councilman who was among those calling for the hearings. "If someone wants to convince me of an argument, I say, 'Show me the data.' That's what I want to see."

After the Fukushima Daiichi nuclear disaster in Japan following the March 11, 2011, earthquake and tsunami, "one of the lessons that I take home is don't trust experts until you see the data," Mosier said, to cheers from some in the audience.

The audience was raucous and occasionally unruly throughout the three-hour session. Rival groups of residents and plant workers hooted and applauded when they agreed with statements, and sometimes booed when they disagreed. When one woman at the microphone paused to look at notes while speaking about nuclear dangers, some in the crowd shouted, "Next speaker."

The meeting took place just five days after Edison announced that it is seeking NRC permission to restart one of two steam generators at the San Diego County plant (Greenwire, Oct. 4).

Edison wants to run the Unit 2 equipment at 70 percent capacity, saying that would prevent 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.

The facility -- which provided power to about 1.4 million residences -- cannot restart without NRC's permission.

"This is going to take a number of months for us to get through," Collins said of NRC's review. "It's our objective to make sure there's a sound technical basis for safety before NRC gives the green light to start up Unit 2."

He also said NRC would hold a future public meeting on Edison's request to restart Unit 2.

The decision must be made at the commission level about whether to order a license amendment, Collins said. Commissioners will be considering a request from Friends of the Earth and the Natural Resources Defense Council.

Gene Stone, with the nuclear watchdog group Residents Organized for a Safe Environment, urged audience members to call NRC Chairwoman Allison Macfarlane and Senate Environment and Public Works Chairwoman Barbara Boxer (D-Calif.), urging the in-depth review.

Dueling arguments

During the meeting yesterday, split reactions from the audience illustrated the divide in opinion about San Onofre.

Plant workers clad in orange T-shirts cheered and hollered when any of the panelists -- particularly Edison's chief nuclear officer, Pete Dietrich -- talked about the utility's commitment to safety.

They also applauded when two of the panelists urged allowing San Onofre to reopen.

"It's a technical problem" at the plant, said Richard McPherson, a Laguna Niguel resident who has worked with the nuclear energy industry since 1963. "The people who are involved know how to fix it. We need to get on and get our electricity back."

California has had to import more power with San Onofre down, McPherson said, and that has been at a higher cost.

But residents and others in the crowd raised a host of concerns about San Onofre, including who will pay the cost of repairs and replacement power, whether there are added risks when operating a plant in quake-prone California and how difficult it would be to evacuate the more than 8 million people who live within 50 miles of the plant.

Cathy Iwane, a Solano Beach resident, was living in Japan at the time of the nuclear disaster there, about 380 miles southwest of the reactors. The utility in charge of that plant had said that it could withstand earthquakes and tsunamis, she said, but no one imagined the extent of devastation that followed the magnitude-9.0 temblor.

"I cannot remind the NRC commissioners and staff enough of their immense responsibility to protect us from a nuclear disaster at San Onofre," Iwane said, to cheers and applause from the audience. "It is an abomination that amidst the wakeup call of Fukushima, Edison has proposed a restart of the defective reactor at San Onofre."

Rochelle Becker, executive director of the Alliance for Nuclear Responsibility, rejected that Edison or San Diego Gas & Electric Co. ratepayers should have to fund expenses connected to the plant's problems.

"We are the ratepayers of Southern California, and we are tired of paying for Edison's mistakes," Becker said. "We've had enough."

Shuttered generators differ

Several in the audience and on a round-table panel asked for more information about why Edison believes it would be safe to restart Unit 2.

If Unit 2 and Unit 3 generators have an identical design and Unit 3 has been pulled from service, Mosier asked, how can the issues with Unit 2 be "fundamentally different." Both generators came from Mitsubishi Heavy Industries in Japan.

An NRC and Edison investigation found that a high velocity of fluids in the generators caused the problematic vibrations that triggered tube wear. For that to occur, Dietrich said, there need to be both adverse thermal hydraulic conditions and insufficient supports.

Unit 2, which was manufactured slightly later than Unit 3, has a better support structure, he said.

Running Unit 2 at 70 percent will prevent the velocity problem, Dietrich said. As well, he said, the utility proposes operating the generator for five months and then inspecting all of its tubes again.

"We feel there are adequate amounts of conservatism there," Dietrich said.

Ray Lutz, founder of the activist group Citizens' Oversight, said that neither NRC nor Edison is talking about the actual cause of the leak. The larger problem, he said, was the number of changes made to the generators when they were installed in 2010 and 2011 as replacements.

He argues that Edison should have gone through the license amendment process at that point. NRC has said that Edison followed proper procedures at the time.

"Are you going to look at this problem of how this crept through your system?" Lutz asked. "It was a design mistake by Edison and they are liable for. The ratepayers should not be paying for anything at this point."

NRC's Collins said he agreed that "there was a design failure here." The agency is continuing to follow up on that issue, he said.