Last week reactor 1 of Plant Vogtle nuclear plant, near Waynesboro, Georgia, shut down, on 20 April 2011, without explanation.  Company officials say they are replacing a breaker and other electronic equipment.  They don’t know why the equipment failed.

In Delaware, on 21 April 2011, the Salem 1 nuclear reactor was shut down because of grass.  The Salem plant is along the Delaware river, and plants periodically grow over the water intakes of the nuke plant.  Salem 1 had to be shut down because the plant growth was blocking cooling water from coming into the reactor.  Officials say it’s back on line now.

Surprisingly, the U.S. Nuclear Regulatory Commission says unexpected shutdowns of nuclear reactors happen every year.