The Danish Atomic Energy Commission (AEK) was created in 1955 with the remit to promote ‘the peaceful exploitation of atomic energy for the benefit of society.’ Between 1956 and 1963 the AEK, which had been preceded by a number of early private nuclear initiatives, established an ambitious atomic energy research facility at Riso, some 40 kilometers west of Copenhagen. For most of this period the AEK was chaired by the celebrated physicist Niels Bohr. In spite of strong support from relevant actors in Danish society and Riso’s management, Denmark never built commercial nuclear power stations. Today Riso has undergone a complete metamorphosis from atomic energy research facility to a national laboratory, doing research and development on a broad range of alternative energy sources. Using concepts and approaches like national innovation systems and technological nationalism, the present paper will explore why and how this remarkable development took place.