Iran's Nuclear Program: Tehran's Compliance with International Obligations

February 7, 2019

Weapon Program: 

  • Nuclear


Iran ratified the nuclear Nonproliferation Treaty (NPT) in 1970. Article III of the treaty requires non-nuclear-weapon states-parties to accept comprehensive International Atomic Energy Agency (IAEA) safeguards; Tehran concluded a comprehensive safeguards agreement with the IAEA in 1974. In 2002, the agency began investigating allegations that Iran had conducted clandestine nuclear activities; the IAEA ultimately reported that some of these activities had violated Tehran’s safeguards agreement. Following more than three years of investigation, the IAEA Board of Governors referred the matter to the U.N. Security Council in February 2006. Since then, the council adopted six resolutions requiring Iran to take steps to alleviate international concerns about its nuclear program. This report provides a brief overview of Iran’s nuclear program and describes the legal basis for the actions taken by the IAEA board and the Security Council. 

For more detailed information about Iran’s nuclear program, see CRS Report RL34544, Iran’s Nuclear Program: Status, by Paul K. Kerr. For more information about the July 2015 Joint Comprehensive Plan of Action (JCPOA) concerning Iran’s nuclear program, see CRS Report R43333, Iran Nuclear Agreement, by Kenneth Katzman and Paul K. Kerr. 


Iran’s nuclear program has generated widespread concern that Tehran is pursuing nuclear weapons. Tehran’s construction of gas centrifuge uranium enrichment facilities has been the main source of proliferation concern. Gas centrifuges enrich uranium by spinning uranium hexafluoride gas at high speeds to increase the concentration of the uranium-235 isotope. Such centrifuges can produce both low-enriched uranium (LEU), which can be used in nuclear power reactors, and highly enriched uranium (HEU), which is one of the two types of fissile material used in nuclear weapons. HEU can also be used as fuel in certain types of nuclear reactors. Iran also has a uranium conversion facility, which converts uranium oxide into several compounds, including uranium hexafluoride. Tehran claims that it wants to produce LEU for its current and future power reactors.

Iran’s construction of a reactor moderated by heavy water has also been a source of concern. Although Tehran says that the reactor, which Iran is building at Arak, is intended for the production of medical isotopes, it was a proliferation concern because the reactor’s spent fuel would have contained plutonium well-suited for use in nuclear weapons. In order to be used in nuclear weapons, however, plutonium must be separated from the spent fuel—a procedure called “reprocessing.” Iran has said that it will not engage in reprocessing.  Pursuant to the Joint Cooperative Plan of Action (JCPOA), which Iran concluded in July 2015 with China, France, Germany, Russia, the United Kingdom, and the United States (collectively known as the “P5+1”), Tehran has rendered the Arak reactor’s original core inoperable. Iran has also begun to fulfill a JCPOA requirement to redesign and rebuild the Arak reactor based on a design agreed to by the P5+1 so that it will not produce weapons-grade plutonium. The agreement also requires Iran to export the spent fuel from this reactor and all other nuclear reactors. 


Read the full report from Congressional Research Services