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Further Reading

Highly-Enriched Uranium [HEU]

Natural uranium contains about 0.7 percent uranium-235, the isotope essential for nuclear weapons, while low-enriched uranium (LEU) as fuel is typically enriched to between 3 and 5 percent uranium-235. Roughly 175 kg of natural uranium is required per kg of highly-enriched uranium [HEU]. About one hundred kilograms of uranium at 20 percent contains 20 kg of U-235. About 20-25 kilograms of HEU is enough for one weapon. Going from natural uranium to HEU requires about 40 times the separative effort needed to go from 20% to around 90% enrichment.

Tehran might enrich some of its growing supply of 20 percent uranium to higher levels of purity. Iran could claim civilian applications for HEU it produced, such as for production of medical isotopes, or for fueling a nuclear powered submarine. Submarine fuel is typically enriched to over 80%, not enough for a bomb, but pretty close to it.

On 12 June 2012 Lieutenant Commander of the Navy for Technical Affairs Rear Admiral Abbas Zamini pointed to the navy's plan to manufacture super heavy nuclear-powered submarines, and stated, "Right now, we are at the initial phases of manufacturing atomic submarines." He noted Iran's astonishing progress in developing and acquiring civilian nuclear technology for various power-generation, agricultural and medical purposes, and said such advancements allow Iran to think of manufacturing nuclear-fueled submarines. He further reminded that using nuclear power to fuel submarines is among the civilian uses of the nuclear technology and all countries are, thus, entitled to the right to make such a use.

Such a submarine project seems highly improbable. The French SNA (Sous-marins nucléaires d'attaque - Nuclear Attack Submarine) Rubis class nuclear submarine was launched in 1988. The Rubis was an elegant design that overcame many of the faults with other nuclear submarines. With a displacement of 2,400 tons they are the most compact nuclear attack submarines to date. The Thyssen TR1700 class of diesel attack submarine, operated by Argentina, had characteristics similar to those of a nuclear submarine. With a surfaced displacement or 2,116 tons and a submerged displacement of 2,264 tons, it was thought by some to have the potential to be modified to use nuclear propulsion, but this project never moved forward. The largest submarines producated in Iran as of 2012 are the Ghadir-class midget submarines, with a displacement (Submerged) of 120 tons. The Iranian Navy's Tareq-class heavy submarines are imported Russia Kilo-class boats.

On 04 June 2012, the Institute for Science and International Security, warned that Iran’s actions at the Fordow plant near Qom possibly suggested plans to make that is highly enriched uranium, well above 20 percent. In June 2011 Iran reported to the IAEA that one hall composed of eight cascades of IR-1 centrifuges would be dedicated to making uranium enriched up to 20 percent. According to a May 2012 report by the Agency, Iran had produced 6,197 kg of UF6 enriched up to 5% U-235 and 145.6 kg of UF6 enriched up to 20% U-235 since it began production of such material. Iran's negotiating team in the June 2012 talks in Moscow with the six world powers said that Iran will not discuss 20% enrichment if the other side ignores its nuclear rights.

Medical patients in both the United States and around the world require access to reliable supplies of radioisotopes for use in medical procedures. The term `medical isotope' includes molybdenum-99, iodine-131, xenon-133, and other radioactive materials used to produce a radiopharmaceutical for diagnostic, therapeutic procedures or for research and development.

Molybdenum-99 (Mo-99) is used to produce technetium-99m (Tc-99m), a medical isotope that is used in diagnostic medical procedures globally every day. Four of five diagnostic imaging procedures in nuclear medicine use this isotope. Approximately seventy thousand patients undergo scintigraphic tests every day throughout the world, including evaluations of the heart, kidneys, lung, liver, spleen, bones and blood flow. About 70 percent of these tests are performed with technetium-99m for the diagnosis of tumors. After injection into the body, technetium-99m goes to specific disease sites in the body or concentrates in organs such asthe heart. Imaging devices such as PET scanners then pinpoint the exact locations and extent of disease and helpidentify the best treatment. The procedures can also be used to monitor patients’ responses to treatment.

Over the past few years, the supply of the short-lived medical isotope Mo-99 and its daughter product technetium-99m have encountered periods of shortage and unreliability, as Mo-99 is produced in only a few facilities around the world, most of which are reaching the end of their projected life, and none of which are located domestically. Necessary for the production of technetium-99m is its parent isotope molybdenum-99, most of which is produced in just five neutron sources worldwide. With a half-life of 66 hours, molybdenum-99 must be delivered to hospitals on a frequent basis. Today, Mo-99 is produced at aging facilities in Europe, Canada and South Africa, primarily using HEU.

Highly-enriched uranium (HEU) is a weapons-usable material - uranium enriched to include concentration of U-235 above 20 percent. Most of the facilities that currently produce large-scale quantities of Mo-99 use HEU targets in the production process. In February 2009, two companies in the United States (Babcock & Wilcox Technical Services Group and Covidien) signed an agreement for the manufacture of molybdenum-99 using an innovative liquid-phase technique involving low-enriched uranium. The technology exists to produce molybdenum-99 from low enriched uranium – South Africa and Australia are currently doing so. The National Nuclear Security Administration (NNSA) and the South Africa Nuclear Energy Corporation (Necsa) announced 06 December 2010 that the first shipment of the medical isotope molybdenum-99 (Mo-99) produced with low enriched uranium (LEU) and approved for patient use had arrived in the United States.

The National Nuclear Security Administration’s (NNSA) Global Threat Reduction Initiative (GTRI) is working to accelerate the development of a commercial domestic capability to produce Mo-99 without the use of HEU as part of its nuclear nonproliferation mission. At the same time, to further the United States Government’s policy of minimizing the use of HEU in civilian applications, NNSA is working with international, large-scale Mo-99 producers to assist the conversion of existing isotope production facilities from the use of HEU targets to low-enriched uranium (LEU) targets. In conjunction with these ongoing efforts, the United States is working with European isotope producers to ensure a reliable supply of Mo-99, which includes the export of HEU until the facilities can convert to LEU targets.

The United States is committed to eliminating the use of HEU in all civilian applications, including in the production of medical radioisotopes, because of its direct significance for potential use in nuclear weapons, acts of nuclear terrorism, or other malevolent purposes. Today there is wide agreement that civilian use of HEU should be minimized, and the US is working with international partners to eliminate its use in radioisotope production worldwide, consistent with this commitment.

At the April 2010 Nuclear Security Summit in Washington, DC, the leaders of 47 countries issued a communiqué and endorsed a work plan that calls for participating states, as appropriate, to collaborate to research and develop new technologies that require neither HEU fuels for reactor operation nor HEU targets for producing medical or other isotopes, and encouraged the use of LEU and other proliferation-resistant technologies and fuels in various commercial applications such as isotope production.