Steam generators en route to San Onofre nuclear power plant

The first of four new steam generators needed to keep the San Onofre nuclear power plant in operation is making its way -- slowly and carefully -- to the facility in northern San Diego County by ship, barge and a tractor-trailer-like vehicle with 256 wheels.

The 650-ton pieces of equipment are intended to extend the life span of the power plant, which has come under scrutiny from regulators in the last year because of safety lapses.

The aging generators will join the facility’s original nuclear reactor, now retired, in the power plant’s growing storehouse of spent radioactive machinery.

The installation is “a major milestone in the station’s history,” said Ross Ridenoure, Southern California Edison senior vice president and chief nuclear officer. “We’re committed to making sure it’s done right.”

To maneuver the 22-foot-diameter generators into the plant’s two reactor domes, crews must cut a 28-foot-wide opening through the 4 to 6 feet of concrete, steel reinforcement bars and thick cables that secure each building. Two generators will be installed by crane inside the power plant’s northern dome this fall, with two more going in the southern dome in fall 2010, according to Southern California Edison officials. The generators create steam that is piped to turbines, which produce electricity.

Similar steam generator projects have been completed dozens of times at other nuclear plants around the country, so the San Onofre undertaking is not new territory, Ridenoure said. However, a 2005 environmental report on the project filed with the state said that most of the cables aren’t designed to be removed. Each reactor will be shut off for about four months while the steam generators are replaced; Edison will purchase additional power to make up for the lost electricity.

“We are taking every reasonable precaution to make sure that this project goes off without a hitch,” Ridenoure said.

But at least one antinuclear watchdog group expressed alarm at the risks of cutting open nuclear facilities in a seismically active region.

“Our concern is actually how much is this going to end up costing if anything goes wrong, and who’s really going to pay?” said David Weisman, outreach coordinator with the Alliance for Nuclear Responsibility, a statewide advocacy group.

Some of the 9,500 tubes in the aging generators have begun to wear down after more than two decades of constant pounding by hot, high-pressure water. The $670-million project is intended to keep the power plant running for 30 to 40 more years, Ridenoure said. The plant’s federal license is valid through 2022 for one reactor and 2023 for the second, Ridenoure said. Edison is considering requesting a 20-year extension from the U.S. Nuclear Regulatory Commission.

The first two mushroom-shaped generators, each 65 feet long, arrived at the Port of Long Beach from Kobe, Japan, several weeks ago; a barge then took the two gargantuan machines to shore at the Camp Pendleton boat basin in Oceanside. Now, the first generator is making its way 15 miles back up the coast, traveling across beach and road.

Edison officials declined to specify the exact route, say whether the generators would travel on Interstate 5 or when they would arrive, citing security concerns. The first two machines are expected to arrive at the plant sometime next month.

The old generators will be stored at a specially constructed facility at the plant, Ridenoure said. Edison officials might move the devices to another facility in Utah in the future. The nonoperational reactor, retired in 1992, is also stored at the plant. Previous attempts to transport the reactor to a disposal site in South Carolina by rail or by sea fizzled.

Federal nuclear officials announced greater oversight of the nuclear generating station in December after discovering that a battery intended to power safety systems had not been operable for four years because of poor maintenance. The plant was previously cited for a number of other, low-level safety problems including falsified safety records

The 2,200 megawatt power plant adjacent to San Onofre State Beach is 78% owned by Southern California Edison and 20% owned by San Diego Gas & Electric and can power 1.5 million homes at any given time.

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susannah.rosenblatt@ latimes.com