Minnesota’s most serious nuclear power plant emergency apparently posed no threat to the public and, in the end, was not all that serious.
The Thursday Prairie Island power plant incident amounted to spilling 522 gallons of chlorine bleach, but forced the state and Xcel Energy to activate a 29-point plan that included considering actions such as preparing to decontaminate the public and notifying school districts within 10 miles to have buses on standby in case evacuation was needed.
No significant action was needed at the Red Wing, Minn., area plant other than cleaning up the bleach, although school districts across the Mississippi River in Prescott and Ellsworth, Wis., delayed classes.
Chlorine bleach is used to clean river water that cools the two Prairie Island nuclear reactors, and a break in a 2-inch PVC pipe allowed bleach to spill into an area surrounded by concrete berms.
The Minnesota Emergency Operations Center in St. Paul that opened early Thursday closed at mid-afternoon after the bleach was removed. Xcel workers still were cleaning up the area and fixing the pipe.
State Emergency Management spokesman Doug Neville said Xcel will be responsible for paying to operate the state center, but he did not expect it to be very costly since the incident was relatively minor.
Representatives from state and private agencies manned the state facility.
There were no injuries and officials said there never was a danger to the nuclear reactors.
“This is a non-radiological event,” state Emergency Management Director Kris Eide said.
Eide and Dennis Koehl of Xcel Energy said the public faced no threat.
An alert like Thursday’s is the second-lowest form of emergency declaration at nuclear power plants. Xcel reported that neither the Prairie Island or Monticello plant has issued an alert or more serious emergency declaration before. Prairie Island began operation in 1973.
Koehl said Xcel is investigating why the PVC pipe sprung a leak. He said the bleach did not get into the Mississippi River or anywhere else outside the area surrounded by berms.
Xcel workers pumped the bleach into another container.
Workers discovered the leak at 3:53 a.m., and Xcel immediately reported the incident to state officials, as required by law. The state opened its Emergency Operations Center in St. Paul, staffed by up to 60 workers from state and private organizations. It closed at 2:08 p.m.
Gov. Mark Dayton said he was notified of the incident at 5:20 a.m. and praised workers for containing the spill.
The leak occurred in what is called a “screen house,” a facility where water pumped from the Mississippi River is treated so it can be used to cool two nuclear reactors. Koehl said bleach is used to kill bacteria in the water.
The pipe that leaked is connected to one of two bleach tanks, and Koehl said the second tank was used to keep both reactors functioning. The nuclear facilities were not affected, he added, and power was not interrupted.
Koehl said air near the leak of what is known as sodium hypochloride was safe, and Xcel workers did not need breathing apparatus to work around the bleach.
Minnesota and Wisconsin officials said the public did not need to take any action and there was no danger.
While Prescott and Ellsworth, Wis., schools delayed their start, Eide said that decision was up to individual school district superintendents; state officials did not recommend the action.
“We are not asking for any kind of protective action,” Eide said.
Emergency operations centers opened in Goodhue and Dakota counties, Minn., and Pierce County, Wis. Wisconsin state officials also opened their operations center.
In the Minnesota Emergency Operations Center, the atmosphere Thursday was calm with few people working on the spill incident. However, officials said, the center was staffed with a variety of state and private agencies just in case something was needed.
The Prairie Island plant, next to an American Indian community of the same name, is 28 miles southeast of St. Paul and six miles northwest of Red Wing. The two reactors in the plant produce enough electricity to power a million homes.
A hotline for people who have questions about their safety has been set up at (651) 297-1304 (for the Twin Cities) and (800) 657-3504.