Xcel launches $68M upgrade at Prairie Island nuclear plant

Xcel Energy Inc. has shut down one of its two nuclear reactors in Red Wing, Minn., for refueling and to replace an original generator and transformer in a monthlong $68 million project that will employ about 1,000 specialized contractors, the utility said Monday.

The project at the Prairie Island nuclear power plant Unit 2 is part of more than $1 billion in investment Xcel is making in its two Minnesota nuclear power plants to extend their operating lives beyond the original 40-year licenses. In 2013, Xcel replaced Unit 2's steam generator at a cost of more than $280 million.

"The upgrades we will make while the unit is offline are investments in the future of Prairie Island, the Red Wing area and the Upper Midwest as a whole," Scott Sharp, director of site operations, said in a statement.

Sharp said the electricity from nuclear power plants is the backbone of Xcel Energy's strategy to generate 63 percent carbon-free electricity in the region by 2030.

Major upgrades to reactors usually occur during refueling outages, which happen every 18 months. About one-third of the fuel rods in the pressurized water reactor will be replaced during this refueling, Xcel said. Unit 1 is still operating.

The Minneapolis-based utility said Unit 2's main electrical generator, which has reached its 40-year operational life, will be replaced at a cost of $55 million. The new turbine weighing 1 million pounds was manufactured in Japan and shipped through the Panama Canal and up the Mississippi River, Xcel said. The plant is located on the banks of the river.

In a second upgrade, contractors also will replace a step-up transformer at a cost of $13 million, Xcel said. It converts the generator's output from 22,000 volts to 345,000 volts for the power grid.

David Shaffer • 612-673-7090 Twitter: @ShafferStrib