The first and only nuclear power plant in Bulgaria ‘’Kozloduy’’ was officially opened on September 4, 1974. It is also the first nuclear power plant in Southeastern Europe. However, the beginning of Bulgaria's nuclear energy sector was marked on July 15, 1966, with the signing of a cooperation agreement between Bulgaria and the then Soviet Union for the construction of the plant. 

The main equipment was supplied by the Soviet Union. Separate facilities were provided by the then German Democratic Republic, Czechoslovakia and Hungary. Several entirely Bulgarian projects, which were implemented for the first time globally in the construction of a nuclear power plant, were also realized. In 1991, Bulgaria launched its last, 6th unit. In connection with the commitments made by Bulgaria for its accession to the EU, the Kozloduy NPP decommissioned the first four nuclear units before the end of their projected lifespan, and as of the beginning of 2007, only the 1000-megawatt units 5 and 6 remain in operation. Currently, work is underway on projects for the construction of units 7 and 8 of Kozloduy NPP with equipment from the US company Westinghouse.