The LaSalle County Nuclear Generating Station is located eleven miles southeast of Ottawa, Illinois and serves the Chicago area. The plant contains two twelve hundred megawatt General Electric boiling water reactors. Unit One was put into operation in 1982 and Unit Two was put into operation in 1984. The reactor uses LaSalle Lake, a man-made two thousand acre lake, for cooling. The plant was built by Commonwealth Edison Company. Exelon Corporation currently owns and operates the plant.
The population in the NRC plume exposure pathway zone with a radius of ten miles around the plant contains about seventeen thousand seven hundred people. The NRC ingestion pathway zone with a radius of fifty miles around the plant contains about one million nine hundred thousand people. The NRC estimates that there is a extremely risk of an earthquake that could damage the plant.
In April of 1994, LaSalle was fined by the NRC for failing to deal with problems involving electrical circuit breakers. In May of 1994, the NRC fined LaSalle for improperly handling radioactive materials.
In February of 1995, a problem with the main steam isolation valves was discovered when Unit Two was being shut down for refueling. Later, one of the isolation valves for Unit One failed to operate correctly.
In June of 1996, there were problems in the water system with strainers that experienced increased pressure. The problem was blamed on sandblasting material clogging the strainers but the same problem recurred and this time it was blamed on foam used for repairs clogging the intake system. Unit One had to be shut down because of the foam in the intake system
In July of 1996, the NRC sent a special inspection team to LaSalle because of a two year trend of declining performance in the water system. The NRC was concerned that the system could not operate safely in case there was an accident. The operators had been given repeated warnings and had repeatedly promised to deal with the problems. Unit One was shut down because of the intake being clogged and Unit Two was shut down for refueling. The operators had to address the problems reported by the NRC before they could restart either Unit. Resolving problems with both Units required over two years to resolve.
In 2006, Unit One was being shut down for refueling when the control system for the turbine malfunctioned. This caused an automatic insertion of control rods to halt power generation. When the instrument panel indicated that three of the one hundred and eighty five control rods had not been fully inserted into the core, a site area emergency was declared. After a reset, only one rod appeared to have failed to insert. The emergency was cancelled in a few hours with no release of radioactivity. Review of the incident found that the problem lay in the sensors and that all the rods had actually been inserted correctly when the automatic shutdown occurred.
Although there were no major accidents at LaSalle, there were repeated problems with equipment that were not addressed by the operators despite repeated warnings by the NRC.
