More than 70 years' worth of information and up to 30 million digital records are to be stored at Nucleus in Wick, Caithness.
They include papers, photographs and plans from nearby Dounreay, as well as Harwell in Oxfordshire, Trawsfynydd in Snowdonia and Sellafield in Cumbria. Nucleus will also store local archives dating back to the 16th Century.
The striking triangular shaped building designed by Reiach and Hall took 12-months to construct. The facility boasts a large public area, a reading room and community space.
Rob Higgins, Nuclear Decommissioning Authority Business Services Director: "We are extremely happy with Morrison Construction who completed the project on time and within budget."
In December 2017 the building won Public Building of the Year and the Editor's Choice of the Year at the at the inaugural Architects' Journal Architecture of the Year Awards.
Architects' Journal Architecture Awards judges commented: "This is an exceptional piece of architecture materially, aesthetically and functionally: it's made well, looks stunning and fulfils, indeed exceeds, its brief – effectively reimagining what an archive building can be in both form and function."