When a 5.8 magnitude earthquake shook the Washington DC and Virgina regions on August 23, the North Anna nuclear plant automatically shut down.

Over a month later the plant is still idle, waiting for the Nuclear Regulatory Commission green light to restart. But when an NRC inspection team, dispatched in early September, found that 25 of the plant’s 27 steel dry cask storage containers had moved several inches during the quake, that restart date may have been pushed off for much longer than initially expected.

At the time, NRC spokesperson Dave McIntyre called the dry cask movement “unexpected and unprecedented.”

Now the NRC has issued a letter to North Anna operator, Dominion Generation, explaining that because the earthquake exceeded North Anna design parameters, the plant will not be allowed to reopen until Dominion can demonstrate that “no functional damage occurred to those features necessary for continued operation without undue risk to the health and safety of the public.”

Dominion emphasized that the letter was only a routine part of the formal process and did not mean the plant was particularly unsafe.

“We have known since the earthquake that we would need the NRC’s permission to restart and this letter is a formal step in this process,” Dominion Director of Media Relations Jim Norvelle told Breaking Energy. “In multiple, detailed inspections, we have found no significant damage at North Anna caused by the quake. We will continue to work with the NRC as it performs its necessary inspections.”

The NRC will closely monitor the plant to ensure that Dominion follows up on requested safety actions, said Administrator of the NRC Atlanta office Victor McCree.

“The plant won’t start up again until we’re satisfied,” said Director of NRC’s Office of Nuclear Reactor Regulation, Eric Leeds.

Photo Caption: Energy Secretary Steven Chu (right) talks with Nuclear Regulatory Commission Chairman, Gregory Jaczko (left) during a House Energy and Commerce Committee hearing, on March 16, 2010 in Washington, DC.