The first nuclear power plant to generate electricity for residential use was a small facility in Obninsk, in the former Soviet Union, on June 27, 1954. The capacity of the power plant was only 5 megawatts. Due to the status of international relations during the Cold War, this accomplishment was not reported widely in the West. Two years later, in August 1956, the Calder Hall Unit 1 power plant became operational in Great Britain. Its initial capacity was 50 megawatts of electricity. Other units were added and it continued to operate for nearly 50 years until March 2003. Calder Hall was the longest operating reactor in history.