Diablo Canyon’s dry cask spent fuel storage facility is beginning to take shape.

Twenty metal rings embedded in an 8-foot-thick concrete slab mark where large casks will one day be mounted. Each cask will contain 32 used but still highly radioactive reactor fuel assemblies.

Pacific Gas and Electric Co. is proceeding apace with the project despite a requested injunction to stop it. Construction on a hillside behind the plant is expected to be completed by year’s end but the first cask will not be loaded until November 2007.

Next to the slab sits another one in the making. It consists of a dense cage of metal reinforcing bars with 20 more metal rings perched atop it. On Tuesday, workers will fill that metal cage with more than 2,000 cubic yards of concrete, a job so big it will take 14 hours to complete.

The rings make this project unique, said Jearl Strickland, Diablo Canyon’s spent fuel manager. The cask will be bolted to the rings. At all other aboveground spent fuel storage facilities, the casks sit unattached on their concrete pads.

"We are the only site in the world that anchors the casks," Strickland said.

Bolting the casks to the pad is intended to prevent them from toppling over during an earthquake, a particular concern along the seismically active Central Coast. At 20 feet tall and weighing 170 tons each, the casks need 8 feet of concrete to provide a sufficient anchor.

PG&E is authorized by the Nuclear Regulatory Commission to build seven such pads to accommodate 138 dry casks. It will initially build only two — enough for 40 casks. The remaining slabs will be added as needed. When complete, it will cover an area the size of one and a half football fields.

Since the Sept. 11, 2001, terrorist attacks, storage facilities for high level radioactive waste have been lightning rods for controversy, none more so than the one at Diablo Canyon.

A federal appeals court recently ruled that the NRC should examine the environmental impacts of a terrorist attack on the dry cask facility. The NRC and PG&E are still deciding whether they will appeal the ruling.

In the meantime, the San Luis Obispo Mothers for Peace and other groups have asked the NRC to order PG&E to stop building the dry cask facility until the federal court case is resolved. Officials with the agency say the commission will rule on the injunction request sometime before the facility opens.

Spent fuel at Diablo Canyon has generated another lawsuit. PG&E has sued the federal Department of Energy in the Court of Federal Claims in Washington, D.C. for its failure to open an underground nuclear storage facility at Yucca Mountain.

The utility is seeking $100 million from the agency to offset the costs it incurred through 2004 developing on-site storage facilities at Diablo Canyon and its defunct Humboldt Bay nuclear plant. A ruling on that case is expected in early September, Strickland said.

Reach David Sneed at 781-7930
dsneed@thetribunenews.com

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