Cause to Worry? VA Earthquake Shifted Nuclear Power Plant Storage Casks

Last week, a nuclear power plant near the Mineral, Va., epicenter of the 5-8 magnitude earthquake that rocked the East Coast was taken offline. At the time, officials said "as far as they knew, everything was safe." While that's still the case, further investigation into the damage revealed reports 25 of 27 spent-fuel storage casks shifted 1 to 4 inches.

How this will affect the plant is still being investigated. The reactors have remained offline since the earthquake.

USA Today has more:

"They vibrated," but each of the 16-foot-tall, 115-ton casks remained upright, safe and "fully intact," said Richard Zuercher, spokesman for Dominion Virginia Power, which runs the North Anna Power Station near the quake's epicenter in Mineral, Va. He said the shifting was noticed shortly after the quake Aug. 23 but wasn't reported to the public, because "it was not considered damage."

This is the first time nuclear storage casks have moved as a result of an earthquake in the USA, says David McIntyre, spokesman for the Nuclear Regulatory Commission. The NRC sent additional inspectors Tuesday to the facility after Dominion reported last Friday that the "seismic activity potentially exceeded" the plant's design.

The North Anna plant was built to withstand shaking of 12% to 18% of the force of gravity, which USA Today reported Dominion spokesman Jim Norvelle as saying is equal to magnitude 5.9 to 6.2. Dominion, according to Zuercher, is still analyzing data from ground sensors: "It's complicated," he said.

The Washington Post reported that the 25 0r 27 casks that moved were located on one concrete pad. There are 53 total casks on two separate pads. These casks store spent fuel rods, which can remain radioactive for thousands of years. The Washington Post has more on the casks:

“This indicates that reactors that have these dry casks in these earthquake-prone areas, they’re going to have to do more to protect them from ground motion,” said Robert Alvarez of the Institute for Policy Studies, who has extensively studied nuclear waste storage. “One thing is to bolt them to the pads, and that’s not a Home Depot-type job. The pads themselves also need to be examined to see if they’re durable enough.”

. . .

Dry casks were designed for temporary storage, Alvarez said, but they have become de facto long-term waste warehouses because the United States has not built a permanent waste repository.

According to the NRC, 55 sites in the United States have nuclear waste in dry-cask storage, including two sites in Virginia and one in Maryland, at the Calvert Cliffs facility in Lusby.

The federal government in 1986 began planning to move the nation’s nuclear waste to a permanent repository at Yucca Mountain in Nevada. But President Obama defunded the partially built project and declared it closed.

While the final report on how the earthquake affected the casks is still out, other reported damage was minimal at the plant.