The £17m earthworks contract is the first major job secured by Keltbray at the Sellafield site in Cumbria.
Keltbray will deliver a development platform for the construction of the Lightly Shielded Store 1, a partnership-led project which will safely store intermediate-level waste.
The firm will also provide a new access road and drainage to the Sellafield site and temporary utility supplies to both the LSS1 construction plot and the adjacent temporary accommodation plot.
Darren James, chief executive officer at Keltbray, said: “We’re delighted to be selected to deliver this critical contract, which will showcase our expertise in delivering to a high specification in safety-critical nuclear environments.”