Utility investigating vibrations that caused shutdown of nuclear reactor

Dominion Virginia Power had a crew of about 20 working Friday to determine what caused the shutdown of its North Anna power facility’s Unit 2 nuclear reactor earlier in the day.

The unit was idled April 7 for a scheduled refueling.

The utility was in the process of restarting it, and the unit was at 60 percent power shortly after 6 a.m. Friday, when operators detected greater-than-normal vibrations in part of the mechanism used to start the reactor. They manually shut it down.
The excessive vibrations were detected in the exciter, which is used during start-up to initiate the flow of electricity from the generator to the grid. The exciter spins with the turbines and electric generator on one long shaft.
[link to www.timesdispatch.com]
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