|Last Updated:||January 1, 2011|
|Location:||Tehran Nuclear Research Center|
|Subordinate To:||Atomic Energy Organization of Iran (AEOI)|
The Tehran Research Reactor (TRR) is a 5MWt pool-type light water research reactor. The United States supplied the reactor to Iran in 1967, together with hot cells for the production of medical isotopes and 5.58kg of highly enriched uranium (HEU) fuel.  The reactor is housed at the Tehran Nuclear Research Center and is capable of producing up to 600 grams of plutonium annually.  In 1987, Argentina's Applied Research Institute converted the reactor to run on low enriched uranium (LEU) instead of HEU, and Argentina subsequently supplied Iran with 115.8kg of safeguarded LEU.  Between 1988 and 1992, Iran conducted undeclared reprocessing experiments with fuel pellets irradiated in the TRR. 
In 2009 the TRR was expected to run out of fuel within the following few years.  After the failure of the proposed LEU-fuel exchange deal between Iran on the one hand, and Russia and France on the other, Iran declared it had started enriching uranium to up to 20% in order to manufacture fuel pellets for the TRR.  In February 2012, Iran loaded the first batch of indigenously-produced fuel rods into the Tehran research reactor. 
In early 2013, the TRR began testing prototype natural uranium fuel assemblies for eventual use in the IR-40 heavy water reactor. 
 Yossi Melman and Meir Javedanfar, The Nuclear Sphinx of Tehran (New York: Basic Books, 2008), p. 84.
 "Nuclear, Iran, Production Capability," Jane's CBRN Assessments, 28 May 2010, www.janes.com.
 Christina Walrond, "Timeline 1967-1993: Argentine Low-Enriched Uranium At Tehran Research Reactor," Institute for Science and International Security, 7 October 2009, www.isisnucleariran.org.
 "Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran," International Atomic Energy Agency (IAEA), 10 November 2003, www.iaea.org.
 David Albright, "Technical Note: Annual Future Low-Enriched Uranium Fuel Requirements for the Tehran Research Reactor," Institute for Science and International Security, 7 October 2009, www.isisnucleariran.org.
 David Albright, Paul Brannan, and Andrea Stricker, "Has Iran Initiated a Slow Motion Breakout to a Nuclear Weapon?" Institute for Science and International Security, 12 July 2010, www.isisnucleariran.org.
 "Iran to Install New Core in Tehran Research Reactor," Fars News Agency, 20 February 2012.
 David Albright and Christina Walrond, "Update on the Arak Reactor," Institute for Science and International Security, 15 July 2013, www.isis-online.org.