When an Earthquake Shuts a Reactor, New York Times blog by Matthew L. Wald, September 8, 2011:
[...] So while an interruption of power from the transformer would have shut down the [North Anna nuclear] plant, this now appears not to have been the first event in the sequence.
Rather, the reactors themselves seem to have undergone changes that caused automatic systems to shut them, [Eugene S. Grecheck, Dominion’s vice president for nuclear development] said. [...]
In the reactor, a uranium atom splits, giving off neutrons [...] Water is crucial to this process because it slows down the neutrons [...]
Because the earthquake moved the water in the reactors, the sensors indicated that the neutron population there was no longer distributed properly, and the system called for the automatic shutdown [...]
Published: September 8th, 2011 at 12:59 pm ET