The reactor was constructed through a $50 million contract with Interatom Internationale Atomreaktorbau GmbH, a unit of the West German steelmaker Kraftwerke Union, which was awarded in 1981. The reactor's fuel rods have originated in the United States, France and the United Kingdom ; the fuel was enriched in the United States and Russia. The International Atomic Energy Agency safeguards the reactor. It was inaugurated by the second President of Indonesia, Suharto on August 20, 1987. The reactor was named after G.A. Siwabessy, Minister of Health and Minister of Atomic Energy under both president Sukarno and Suharto.