History of the realization of the thorium regime in the Soviet Atomic Project

Archival materials are presented which outline the history of the world's first realization of the thorium regime in the industrial heavy-water reactor OK-180 in the Soviet Union. Computational and experimental results that enter into the treatment of the thorium regime in various versions of the heavy-water nuclear reactor, including homogenous and gas (helium)-cooled reactors, are briefly discussed. Information on the relevant governmental resolutions and on the basic stages in the research and development work on the OK-180 reactor for operating in the thorium regime is presented. No information on the realization of the thorium regime in the industrial heavy-water reactor OK-180 was published in the past.