This will be a quick throwaway diary to update some of the latest news in nuclear safety. Those who are prone to follow such things will recall that a magnitude 5.8 earthquake occurred on August 23 of this year. It was located in the vicinity (about 11 miles) of the North Anna Nuclear Power Plant in Louisa County, Virginia. This earthquake was felt along the East Coast of the United States as far away as New York City. It was responsible for the National Park Service closing the Washington Monument in D.C. to assess the damage caused by the event.
The two reactors at North Anna were scrammed as a result of the quake, and they have been off-line ever since. Today, the Nuclear Regulatory Commission (NRC) approved the restart of these reactors after an inspection and careful analysis of the findings of this inspection.
The PDF of the announcement can be found online. It states the following:
The Nuclear Regulatory Commission, after careful analysis of inspection findings and related information, has concluded Dominion Generation’s North Anna Unit 1 and 2 reactors can be restarted. The North Anna reactors, in Louisa, Va., have been shut down since Aug. 23, when a magnitude 5.8 earthquake occurred about 11 miles from the plant.
Since, however, "the earthquake shook the reactors more strongly than the plant’s design anticipated," the NRC did not allow the owner of the plant (Dominion Generation) to restart the plant until the company answered "dozens of detailed questions." That process, including detailed inspections, has taken several months, but now the NRC staff is "satisfied the plant meets our requirements to restart safely."
Is Dominion now off the hook? Not at all. They are still required to meet the following commitments (taken from the NRC announcement cited above):
- Updating North Anna’s Final Safety Analysis Report to incorporate
information from the quake and subsequent analysis;
- Additional characterization of the fault responsible for the
Aug. 23 quake, as well as any special ground motion effects at
North Anna;
- Re-evaluating plant equipment (including an assessment of
potential improvements) identified in earlier seismic reviews;
- Developing any needed inspections or evaluations for components
within the North Anna reactor vessels; and
- Permanently updating seismic monitoring equipment for the North
Anna reactors and dry-cask spent fuel storage facility.
The NRC will also be carefully monitoring the restart of the two reactors.
This is how regulation is supposed to work.
UPDATE (11/15): The North Anna Nuclear Plant is ready to begin generating electricity. (source)