From Rockford Register Star (1/30/2012 8:43PM):
ROCKFORD — A loss of power coming into the Byron nuclear plant caused one of two reactors to automatically shut down about 10:15 a.m. today.
Backup diesel generators were activated after the power outage and were being used for safety equipment that vents heat from the reactor, according to a spokeswoman from the Nuclear Regulatory Commission in Lisle.
“Right now, we believe the plant is in a stable condition,” said the NRC’s Viktoria Mitlyng. “There is no danger to the workers or the public.”
Exelon, which operates the Byron plant, declared an “unusual event” — the lowest of four emergency classifications established by the NRC — after the outage.
Mitlyng said two NRC resident inspectors are monitoring the plant.
Byron station spokesman Paul Dempsey said crews are still trying to determine how power coming to the generator was interrupted. The steam release, which he said made a whooshing sound, was expected to continue into the evening.
The steam contains tritium, a hydrogen isotope with low levels of radioactivity. Exelon, in a news release, said tritium occurs naturally and is found in virtually all surface water, although it is found in greater concentrations near nuclear reactors.
It was the first automatic shutdown of the plant since 2007 when a dime-sized hole in a water cooling pipe led to the shutdown of both reactors.
(Full article at the link)
They all say the same thing. It is safe, radioactive materials are natural. Soon they'll be talking about bananas and transcontinental flights and X-rays.
From wiki on tritium from fission:
Tritium is an uncommon product of the nuclear fission of uranium-235, plutonium-239, and uranium-233, with a production of about one per each 10,000 fissions. This means that the release or recovery of tritium needs to be considered in the operation of nuclear reactors, especially in the reprocessing of nuclear fuels and in the storage of spent nuclear fuel. The production of tritium was not a goal, but is rather just a side-effect.