Nuclear energy accounts for about 3% of Brazil's electricity. It is produced by two pressurized water reactors at Angra, which is the country's sole nuclear power plant. Construction of a third reactor begun on 1 June 2010, but it is currently stalled. The sole Brazilian company in charge of nuclear energy production is Eletronuclear. Uranium exploration, production and export in Brazil is under state control through Indústrias Nucleares do Brasil although the government has announced it is ready to involve the private sector in the nuclear fuel industry. Brazilian nuclear activities Early years (1930–60) In Brazil, theoretical research in the field of nuclear energy began at the University of São Paulo (USP) in the late 1930s. The following decade, Brazil became a supplier of mineral resources (monazite, thorium and uranium) to nuclear experimentation projects in the United States, such as the Manhattan Project. In 1947, Álvaro Alberto, a Navy official and a vocal supporter of nuclear power, wrote the first Brazilian nuclear policy plan to be approved by Brazil's national security council, the Conselho de Segurança Nacional (CSN). Implementation of the plan began in 1951, with the establishment of Brazil's national research council, the Conselho Nacional de Pesquisas (CNPq), and the nomination of Alberto as its president. The institution's general purpose was to promote technological and scientific research in all areas of knowledge and CNPq had specific responsibilities related to the development of nuclear energy; such as promoting research on relevant mineral resources and undertaking the necessary measures to boost the industrialization of nuclear energy. The path toward developing a Brazilian nuclear sector included the nationalization of nuclear activities and specific compensations for exporting strategic raw materials. Accordingly, Brazil attempted to negotiate trade agreements that, in exchange for Brazilian raw materials, would include provisions to grant easier access to sensitive technologies and training for Brazilian nuclear engineers. This policy granted Brazilian scientists and engineers opportunities to undertake academic exchanges and training in the U.S. CNPq sought to acquire nuclear technology from the U.S. and other countries. Washington, however, rejected Alberto's request to purchase a cyclotron from General Electric, which would have allowed Brazil to conduct advanced nuclear physics experiments. Alberto also started negotiations for the acquisition of ultracentrifuges from West Germany. By the mid-1950s Brazil's nuclear program had purchased 3 West German centrifuges for US$80,000. Although the centrifuges arrived in Brazil in 1956, they only became operational in the 1970s.