Mammoet crews have replaced a 40-year-old main electric generator at a nuclear power facility in Prairie Island, a Mdewakanton Sioux Indian reservation in Goodhue County, in the American (US) state of Minnesota.

The 454 metric tonne (one million pound) generator was one of the oldest operational generators in the US. It was lifted from its location in the Prairie Island Nuclear Power Plant utilising a gantry, and was then slid out of the facility and transported off site using 24 axle lines of Mammoet SPMT. The new generator was brought in and installed using the same method in reverse.

Mammoet’s selected method allowed the client to continue maintenance work until the last moment, optimising efficiency. During the generator switch, Mammoet also accelerated removal of equipment that was no longer needed. The re-installation operation was finished three days ahead of time.

Each of the two new pressurised water reactors can generate about 550 megawatts of electricity, enough to power approximately one million midwestern homes. The generator exchange completed by Mammoet means that the plant is now more likely to meet the set licence extension requirements, and prove its profitability, allowing it to continue operations.