Reactor at illinois nuke plant shuts down after power loss
The Byron nuclear station northwest of Chicago and 17 miles from downtown Rockford in Ogle County, Illinois declared an "unusual event" this morning when an apparent fire that they claim wasn't a fire in a transformer caused loss of offsite power. Emergency diesel generators automatically started to keep vital systems - except, of course, for spent fuel pool circulatory cooling - going. Emergency relief valves outside containment opened to relieve steam pressure after the emergency shutdown, and that steam was reported by Exelon to contain an 'expected' amount of tritium contamination.
UPDATE: At 9:54 PM last night an earthquake measuring 3 on the Richter scale occurred near McHenry, Illinois, ~51 miles east-northeast of the Byron Station nuclear plant. Despite low intensity, the quake was felt from Wisconsin through northern Illinois and the Chicago area and into northeastern Indiana.
[A note for those keeping track, about "expected" amounts of tritium coming out of the SECONDARY system when it's vented - it got there due to leaks in the steam generators, and those absolutely DO NOT selectively allow just tritium to get out of the reactor coolant loop. It's just that they're only reporting tritium and not reporting any other isotopes - like, say, iodine or xenon or krypton - that might 'normally' come through those very same primary-secondary leaks. See NRC: Groundwater Contamination (Tritium) at Nuclear Plants.]
Byron has quite a history of tritium contamination of groundwater that the Nuclear Regulatory Commission hasn't actually required them to do anything about, any more than NRC has required Exelon to do anything about the very same problem at their Braidwood station near Braceville, Illinois. Or any of the other dozens of nukes under their jurisdiction that have notable tritium leak issues. At Byron, standing water in vaults along the river water 'blowdown' line was reported in February of 2006 to contain tritium concentrations of 86,000 pCi/L [picocuries per liter], which is more than four times the EPA limit for drinking water. The Illinois EPA, however, did issue a violation notice in April of 2006 for "impairment of resource groundwater" and discharging waste-containing contaminates from areas OTHER than permitted points, and other (unspecified) violations of the plant's discharge permit.
Since 1997 the Byron plant has been fined hundreds of thousands of dollars for various violations of its operating license, including falsifying surveillance reports, silt buildup, and Emergency Core Cooling System venting.
Workers were evacuated and area fire departments were called to standby status while the NRC Region III office in Lisle, Illinois activated its incident response center. The response from Viktoria Mitlyng of NRC Region III's incident response center was:
"It is not a huge concern."
That's ever so nice to know. If one is inclined to believe anything the nukes or their erstwhile regulator/promoters have to say about things.