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Tehran Research Reactor (TRR)

The Tehran Research Reactor (TRR) is a 5 megawatt-thermal (MWth) pool-type light water research reactor. The United States supplied the TRR to Iran in 1967 and weapon-grade uranium fuel for the reactor. The International Atomic Energy Agency (IAEA) inspects this reactor.

After the 1979 revolution, Iran was no longer able to procure replacement fuel from the United States or Europe.  In 1987, the AEOI paid Argentina’s Applied Research Institute (INVAP) $5.5 million to convert the reactor’s fuel from 93 percent enriched uranium to slightly less than 20 percent enriched uranium, just below the cutoff for highly enriched uranium (HEU). (A timeline of the fuel requirements for the Tehran Research Reactor can be found here: Argentine Low-Enriched Uranium at the Tehran Research Reactor) The reactor has been operating with LEU fuel since 1993.

Of the original U.S.-supplied fuel, about 7 kilograms of irradiated HEU remains stored at the reactor site.  Iran likewise is storing irradiated Argentine-supplied LEU

The reactor has operated at 3 MW-th, partially due to a shortage of fuel. The Tehran Research Reactor is expected to run out of Argentine-supplied fuel at the end of 2010 or sometime in 2011.
Iran used this reactor to conduct activities possibly linked to early efforts to develop nuclear weapons.  Without notifying the IAEA Iran irradiated uranium oxide (UO2) targets in the TRR and separated plutonium in glove boxes at Tehran Nuclear Research Center (TNRC) laboratories.  Iran also admitted to producing small amounts of polonium-210 in the TRR in the early 1990s through the irradiation of bismuth targets.  Polonium 210 is a well-known radioactive material used in a beryllium-polonium neutron initiator that starts the chain reaction in a nuclear weapon.  Iran claims that the polonium was produced as part of a study of the production of neutron sources for use in radioisotope thermoelectric generators and not for use in a nuclear weapons neutron initiator.  The TRR was under traditional safeguards at the time of the undeclared plutonium experiments and polonium production.  This type of safeguards is not designed to detect such small-scale activities.

Fuel Swap Proposals

Tehran Research Reactor Fuel Requirements