Security equipment failure prompted 'unusual event'
Security equipment issues triggered a "notification of unusual event" at the Prairie Island nuclear plant Wednesday. The declaration was terminated after about three and a half hours.
Prairie Island plant officials made the declaration around 2:18 p.m. Oct. 31 after some security equipment temporarily failed, according to Xcel Energy, which owns the plant. Plant conditions were assessed and the declaration ended just before 6 p.m.
Details of the failure could not be released because they were related to security issues, an Xcel spokesman said.
"This event did not involve a hostile action and plant operators analyzed and addressed the issue and restored the equipment," he said.
The plant remained secure throughout the event, officials said, and there was no danger to the public or employees.
Operations also remained unaffected, Xcel representatives said. Unit 2 remained at full power while the planned refueling outage of Unit 1 that began Oct. 23 continued.
A notification of unusual event declaration is the lowest of four emergency classifications established by the U.S. Nuclear Regulatory Commission based on pre-determined criteria.
The declaration means there is a potential reduction in the level of safety at the plant, but no threat to public safety. It alerts plant staff to prepare for emergency response if it becomes necessary.
The Minnesota Public Utilities Commission on Thursday took a step toward agreeing with Xcel Energy's determination that a planned uprate at the Prairie Island nuclear plant is no longer a good idea.
Still, the commission will accept comments about whether the company should be allowed to terminate the uprate process in case there are objections. In 2008 Xcel Energy received permission for the increase in power at the Prairie Island plant. But this spring the company said it was re-evaluating the uprate and on Oct. 22 filed a new statement saying it no longer believed the uprate was "in the best interest of its customers."
During a spring refueling outage Xcel discovered a new system that will allow it to spread out the outages and eliminate one per year. That savings could be comparable to what ratepayers would have seen from the uprate, Xcel said in the October filing.