The NRC announced that they have sent an augmented team to assist with the inspections at the North Anna nuclear plant. No major damage is being cited by the NRC, but they mention the ground motion may have exceeded the plant design.
The NRC was under fire in the 1970′s for first ignoring the evidence of an earthquake fault directly under the North Anna reactors and later for going ahead and giving it a license to run. Now people are beginning to question the NRC’s 2003 license extension allowing North Anna to operate for more than 20 years past the plant design life.
We have also determined that seismic automatic shutdown equipment is not mandatory in nuclear power plants. The installation mandate was dropped as a priority over the cost and man hours involved. We have so far not found a clear answer about North Anna and if it has a seismic shutdown system. The events during the shut down cite the loss of offsite power as the event that automatically shut down the reactors. This lead to questions about the existence of a seismic trip system at North Anna. To date Dominion Virginia has not responded to our emails asking about a seismic trip system. The only public comment made by Dominion to the media was that they have sent a seismic “black box” unit to the manufacturer to determine if the plant shook beyond design basis.
There are also concerns about the cooling capacity of the artificial lake North Anna uses for cooling water. During the emergency shutdown unit 1 was cooled down first, leaving unit 2 in hot standby. Dominion reversed an earlier plan to add a third reactor to the lake cooling system, instead planning a cooling tower for it. Concerns submitted to the NRC that the lake could not sustain cooling for 3 reactors appears to have been the reason for the change. It is not clear if the lake has sufficient capacity to rapidly cool down both reactors at once if needed in an emergency.
The stack of questions for the NRC to answer regarding the North Anna nuclear plant are piling up.
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