A demolition team is preparing to move into Craig More House at Dounreay.
The redundant three-story building, known as D9807, served as an office block until tenants Nuvia moved out last year.
It is now surplus to requirements.
Strip-out of the building is due to begin in September with the removal of asbestos. Demolition is scheduled for December.
Built of pre-cast concrete in 1961, the block has a floorspace in excess of 8000 sq ft.
More than 160 different facilities have been demolished so far during site decommissioning.
Demolition has averaged almost 100 sq ft a day since the formation of the Nuclear Decommissioning Authority in 2005.