Off-Site Power Failure Shuts Down Two Millstone Reactors
WATERFORD The Millstone nuclear power plant's number 2 and 3 reactors were shut down early Sunday morning due to a loss of "off-site power," according to a spokesman for the Nuclear Regulatory Commission.
Neil Sheehan, public affairs officer for the NRC, said Sunday in a release that all safety systems functioned as designed and that there were no health or safety issues to the public as a result.
Sheehan said the plant's emergency diesel generators activated and provided power to the safety systems until power could be restored.
Sheehan said the shutdown, which occurred at about 7:15 a.m., was classified by the NRC as an "unusual event," the lowest of the agency's four emergency classifications.
http://www.courant.com/news/connecticut/hc-waterford-millstone-0526-20140525,0,1946531.story
They state that the reactors are still shutdown pending a review of the incident, but I also know that when a reactor is SCRAM'd or tripped after a long operation they tend to develop "neutron poison" isotopes that take a few days to decay away. The Neutron poisons prevent fission of uranium and so the reactor cannot restart until they are gone.