Project Kr was a project run by Cadmus with the intention of cloning Superman. The product of this project was Superboy, whom Cadmus intended to replace Superman if he ever died or "turned from the Light". Superboy himself is sometimes referred to as "Project Kr" or "the weapon" by Cadmus staff, such as Mark Desmond.
Superboy was telepathically controlled and educated by three G-Gnomes that lived with him in his pod. He was fed yellow sun radiation by a solar suit. On July 4, 16 weeks after Superboy's creation, Superboy was released by Robin, Aqualad and Kid Flash. Project Kr was exposed and presumably dismantled.
Kr is the atomic symbol for the element krypton.