The companies include Sellafield, Magnox, Research Sites Restoration, Dounreay Site Restoration, National Nuclear Laboratory and Springfield Fuels.
The contract is scheduled to commence in August 2013 and valued at £380m.
Kaefer C&D operations director Paul Hoyle said, "We are delighted that the quality of our work, our proposals for innovative working and the professionalism and experience of our people has been recognized by us being awarded this prestigious contract.
"It further enhances our reputation within the industry and reinforces our intention to continue to grow the business via the competitive tendering process," Hoyle added.
Kaefer C&D will utilize local labor and suppliers and employ modern techniques and processes that were proved at various sites of Kaefer across Europe.
Kaefer C&D operations manager Paul McKeown said, "The experience that KAEFER C&D can bring to delivering this contract cannot be overstated."
"In addition, the contract is expected to provide major training opportunities with added benefits to the local economy and local suppliers particularly in the Sellafield/Cumbria area," McKeown added.
