Despite Romania's ratification of the nuclear Non-Proliferation Treaty in 1970, a covert nuclear weapons development program was carried out under the regime of Romanian dictator Nicolae Ceausescu from 1965 to1989. After the overthrow of Ceausescu in 1989, the weapons program was terminated and much of the nuclear infrastructure was dissolved due to Romania's desire to improve its diplomacy with western nations and gain access into the European Union.
In 1992, Romania contacted the International Atomic Energy Agency to report the discovery of 100 milligrams of plutonium that had been separated in December 1985 at the Pitesti Nuclear Research Institute.
An article in Nucleonics Week in June 1992 by Ann MacLachlan reported that the plutonium had been separated from fuel irradiated in the country's Triga research reactor supplied by the United States in the 1970s. The experiment was a clear violation of Romania's commitments made under the NPT and pointed to a more extensive nuclear weapons program that may have been covered up.
Following Romania's announcement, the Bucharest government agreed to full IAEA inspections and control of its facilities, according to a 1995 Russian intelligence report. It agreed to suspend its nuclear activities and install IAEA monitoring devices at its facilities.
On March 30, 1998, Romania and the United States signed a bi-lateral agreement to promote military relations between them and to work against the trafficking of chemical, biological and nuclear weapons.
Five years later, in September 2003, the Tripartite Initiative, an agreement between the United States, Russia and the IAEA to return Russian-supplied fuel from foreign nuclear reactors back to Russia, was implemented in Romania. The IAEA removed about 30 pounds of highly enriched uranium reactor fuel which had been stored at the Pitesti Institute and returned it to Russia for conversion into low-enriched uranium. The quantity of the fuel was potentially enough to make a nuclear bomb. As part of the agreement, the United States agreed to help pay for the conversion of the Triga reactor from burning HEU to low-enriched uranium.
Because of its compliance with the IAEA, Romania is thought to be weapons free and conducting nuclear activities for civilian purposes only.