Exelon (NYSE:EXC) plant operators removed Unit 2 of the Dresden nuclear station from service Jan. 13 at 7:04 p.m. CT, after receiving a system notification for an elevated water level in the reactor.
The unit shut down and performed as expected, and the water has been returned to normal operating levels, Exelon said in a news release.
Station technical experts are looking into the cause of the issue. Dresden Unit 3 continues to run at full power.
Dresden 2 was still listed at zero generation in a daily reactor status report issued early Jan. 14 by the Nuclear Regulatory Commission (NRC).
“The source of the transient was a failure of both controllers in the Feedwater Level Control system,” according to an NRC event notification report.
Located about 60 miles southwest of Chicago, the plant’s two boiling water reactors (BWRs) are capable of together producing about 1,900 MW at full power. Dresden Unit 3 returned to service in late November after a regularly-scheduled refueling and maintenance outage.
Dresden and Exelon’s other nuclear units in Illinois have been the focus of much attention in recent months as Exelon CEO Chris Crane has been making the case that current market structures don’t properly reward carbon-free baseload power.
The Illinois Legislature recently had state agencies issue a report on the importance of the Exelon nuclear fleet to grid reliability and controlling growth of greenhouse gas emissions.