Both reactors at the North Anna plant will be going into a cold shutdown this week, which changes the atmospheric conditions of the coolant system to make it safe for inspectors to walk through the containment structure and check for any quake damage.
[pullquote_left]Notification Date: 08/25/2011
Notification Time: 01:48 [ET]
Event Date: 08/25/2011
Event Time: 01:18 [EDT]
Last Update Date: 08/25/2011[/pullquote_left]
[quote]UNUSUAL EVENT DECLARED DUE TO AN AFTERSHOCK EARTHQUAKE
On August 25th at 0118 EDT, North Anna Power Station declare an Unusual Event due to seismic activity onsite (EAL HU 1.1). Both units are currently shutdown and electrical power is being supplied from offsite. There were no personnel injuries. There was no radiological release. Site structure and system inspections are in progress. No damage has been identified.
The NRC Resident Inspector and state and local authorities have been notified.[/quote]
Dominion reported no “major” damage to the facility on Tuesday as diesel generators were started to keep the reactors’ radioactive cores cool until off-site power was restored in a few hours.
Jim Norvelle, spokesman for plant operator Dominion Virginia Power, said Wednesday that the plant “will be shut down until it is safe to restart,” though he could not say when exactly that would be.
“They will go over this with a fine-tooth comb, with our resident inspectors beside them, to make sure there is no damage of any kind,” Ledford said.
“There will be an extensive walk-down, including inside the containment (vessel) once both units are in cold-shutdown,” said Joey Ledford, a spokesman for the Nuclear Regulatory Commission‘s regional office in Atlanta.
Coincidentally, the Nuclear Regulatory Commission had scheduled for Wednesday the announcement of a new senior resident inspector for the North Anna plant. At least two resident inspectors are assigned to every U.S. nuclear plant, according to the NRC. Despite the timing of that release, the new inspector had been on site at North Anna for several weeks, and the announcement was unrelated to the earthquake, Ledford said.
Combine that with the initial reports that the earthquake caused some of the asbestos insulation around the some of the piping to come loose is significant because that insulation isn’t just sort of lying around on top of the pipes, it is seriously glued into place. So for some of it to come loose means there was a whole lot of shaking going on.
So, a whole lot of shaking going on, combined with only one coolant pump per unit running (after a 24-hour [or more] down period), combined with going into cold shutdown. Add it up, folks. The damage at North Anna may have been quite serious.
Notably, part of North Anna’s back-up generator plan was among the concerns pointed out by the Nuclear Regulatory Commission just three months ago, when the NRC conducted inspections of all U.S. nuclear plants in the wake of the disaster at Japan’s Fukushima Daiichi plant.
“The inspector determined that during a loss of power scenario there was no procedural guidance to obtain on-site diesel fuel from an underground tank located away from the plant protected area,” the post-Fukushima report said.
In addition, the report noted that one of the plant’s portable generators was not functional when tested, though that was not one of the large, non-portable diesel generators used on Tuesday.
Among other concerns related to seismic risk, inspectors found other small vulnerabilities at the plant, such as seismic floodwalls being located in a non-seismic building and certain safety equipment that was not designed to withstand an earthquake.
- New Photos Of North Anna Nuclear Power Plant Venting Steam And Inspections After Earthquake (enformable.com)
- North Anna Update: Nuclear Power Plant Still Without Power – Venting Steam (enformable.com)
- BREAKING: 5.9 Earthquake Strikes Near 7th most At-Risk Nuclear Power Station for Earthquake Damage – If foreshock, then worse is yet to come (enformable.com)
- North Anna Nuclear Power Station Restores Off-Site Power – Still No Word On Restart of Reactor (enformable.com)
- Emergency diesel generator fails at Virginia nuke plant hit by 5.9 quake (enenews.com)
- Strange: Spokesman says workers at Virginia nuke plant were preparing to manually shut down reactors after quake when system went into automatic shut down – Another spokesman says “it was a manual shutdown” (enenews.com)
- Experts concerned about North Anna: “Uncomfortably close” to maximum quake that nuke plant was designed to withstand (enenews.com)