LaSalle County Nuclear Generating Station
From Wikipedia, the free encyclopedia
The LaSalle County nuclear power station, located 11 miles southeast of Ottawa, Illinois serves Chicago and northern Illinois with electricity. It has two General Electric boiling water reactors. The plant is owned and operated by the Exelon Corporation.
[edit] Site Area Emergency
On 20-Feb-2006 the Chicago Tribune reported that a "site area emergency" (a classification only one level down from the "general emergency" that occurred at Three Mile Island) was declared at the plant at 12:28 a.m. This was the first SAE decleared at a US nuclear plant since the 1991 SAE at the Nine Mile Point Unit 2 reactor in New York, although several SAEs have occurred in intervening years at fuel cycle plants or US government owned facilities regulated by the US Department of Energy instead of the Nuclear Regulatory Commission. It was the fourth NRC SAE in US nuclear history.
Workers were shutting down Unit 1 for refueling at 12:28 AM when the plant's turbine control system malfunctioned, SCRAMing the reactor. The reactor had been operating at 6 percent power output at the time of the SCRAM. Plant instruments indicated three of 185 control rods used to shut down the reactor were not fully inserted triggering the emergency declaration. After a reset, the plant's instruments indicated that only one control rod was not fully inserted, not three. The emergency ended at 4:27 AM with no release of radioactivity.
Post trip evaluations have confirmed that all control rods were fully inserted within four minutes of the reactor scram. A review of the post-trip data suggests that there were only control rod indication problems on the three subject rods and all control rods were fully inserted immediately at the time of the reactor scram. Follow-up evaluations also demonstrated that even if the three subject control rods remained fully withdrawn in a cold shutdown condition, the reactor would have remained adequately shutdown. (ref NRC Event Number 42348)