This is an excerpt from a draft of something I'm working on for my day job, so it's still a bit rough.  

Relevant IAEA reports are found here.

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Outstanding IAEA Issues with Iran

Since its investigation of Iran's nuclear programs began in 2002, the International Atomic Energy Agency (IAEA) has discovered a series of clandestine nuclear activities. Some of these violated Iran's IAEA safeguards agreement. Others did not, but have nevertheless raised suspicions regarding Iran's claim that its nuclear programs are exclusively for peaceful purposes. During the course of this investigation, Iran both failed to disclose some of its nuclear activities to the agency and misled inspectors about others.

The IAEA is currently attempting to obtain answers to several unresolved questions concerning Iran's nuclear activities.

Iran's Nuclear Programs

Tehran currently has two nuclear programs which concern the IAEA: a gas-centrifuge based uranium enrichment program and the construction of a heavy-water moderated nuclear reactor.

We've talked about the centrifuge program before.

The spent nuclear fuel from heavy-water reactors contains plutonium - the other type of fissile material used in nuclear weapons.

Iran claims that it wants to produce low-enriched uranium (LEU) for its light-water moderated nuclear power plant currently under construction near the city of Bushehr, as well as additional power plants Tehran plans to construct. Light water reactors are more proliferation-resistant than heavy-water reactors. Iran says that its heavy-water reactor is intended for the production of medical isotopes.

IAEA Demands

The IAEA Board of Governors has adopted a series of resolutions which call on Iran not only to comply with its safeguards agreement, but also undertake "transparency measures." The latter are not required by Tehran's safeguards agreement, but the agency argues that they are necessary for it to be able to resolve certain issues concerning Iran's nuclear programs.  For example, the IAEA has asked Iran to allow agency inspectors access to non-nuclear facilities. Iran has provided some access to these facilities, but the agency has requested additional visits.

The board has also called on Iran to ratify its additional protocol to its safeguards agreement.  Although Iran has signed the protocol and has been complying with its provisions, the protocol still needs to be ratified by Iran's parliament before entering into force.

Additionally, the agency has called on Iran to "reconsider" its ongoing heavy-water reactor construction.

Uranium Enrichment Program

The agency is still trying to resolve questions concerning Iran's enrichment programs involving two types of centrifuges - the P-1 and the more-advanced P-2.

The agency is concerned that Iran may have conducted undisclosed work on both of  these programs and also possess an ongoing clandestine centrifuge program. Iran has not fully forthcoming to the IAEA about either one of these programs.

Procurement Efforts

Iran received most, if not all, of its centrifuge materials from a clandestine supply network run by former Pakistani official Abdul Qadeer Khan.  The IAEA's investigation of these efforts has been hampered by Iran's lack of full cooperation. For example, Iran has both repeatedly lagged in fulfilling IAEA requests for documentation and  provided the agency with false information regarding its centrifuge procurement efforts.

Iran has acknowledged receiving centrifuge materials and components during the late 1980s, as well as during the first half of the 1990s.  Tehran has also provided the agency with some information regarding these acquisitions, as well as related offers from foreign suppliers.

According to a November report from IAEA Director-General Mohammed ElBaradei, Iran has recently provided the agency with substantial amounts of additional documentation regarding its P-1 procurement activities.  This information appears to have resolved some of the discrepancies in Iran's previous accounts, but the IAEA has requested additional documentation.  

Iran claims that it conducted no work on its P-2 centrifuge program between 1995 and 2002, but the IAEA is skeptical of this claim. ElBaradei reported that the agency is assessing documentation provided by Iran indicating that an Iranian contractor who had worked on the P-2 program obtained related materials that it had apparently not disclosed to the IAEA.  Iran had told the IAEA that it had not procured foreign P-2 centrifuge components - a claim subsequently found to be false.

Agence France Presse reported Jan.24 that, according to unidentified diplomats, "Iran may have received in 1997 three sophisticated P-2 centrifuges...from the black-market network of disgraced Pakistani nuclear scientist Abdul Qadeer Khan."  Iran has denied this.

Enriched Uranium Particles

The IAEA is still investigating the origin of some LEU particles found in Iran by agency inspectors. Iran has admitted to enriching uranium to very low levels, but the uncertainty regarding these LEU particles suggested that Iran may have conducted additional centrifuge experiments that it concealed from the IAEA.  Iran claims that particles of uranium enriched to higher levels came from imported centrifuge components.

According to ElBaradei's November report, environmental samples taken from a location in the United Arab Emirates where centrifuge components from the Khan network were stored before being shipped to Iran showed no "traces of nuclear material."  

A Western diplomat told Arms Control Today in November that these findings indicate that the LEU particles did not come from these components - a finding that could contradict Iran's account. But according to a State Department official, Washington is almost certain that, based on an examination of uranium samples taken from Iranian facilities and Pakistani centrifuge components, all the LEU particles found in Iran originated in Pakistan. Any further discoveries of  undeclared Iranian-produced LEU would likely only reveal previously concealed P-1 experiments, the official said.

Arms Control Today reported in October that, for all practical purposes, the investigation has resolved similar concerns about highly-enriched uranium particles that the IAEA has also found in Iran.

Uranium Mining  

The IAEA is investigating questions about Iran's Gchine uranium mine.  U.S. and European officials have told Arms Control Today that questions with respect to the mine's operation suggest that Iran's military or an affiliated organization might have been working at the mine in an effort to obtain an independent uranium source.

Plutonium

The IAEA reported in November 2003 that it conducted plutonium-separation experiments. The agency has since determined that Iran provided inaccurate information to the agency concerning the dates of these experiments. Iran first said that it completed this work in 1993 but has now admitted continuing experiments until 1998. The agency is still investigating the matter.

A September report from ElBaradei stated that the IAEA has not received information it has requested regarding Iran's efforts to obtain equipment for hot cells - facilities that can be used to produce medical isotopes, but can also be used to separate plutonium from spent reactor fuel.  ElBaradei has reported that Iran has attempted to procure hot cells with specifications more consistent with plutonium separation than for isotope production.  

Iran says it is no longer attempting to build hot cells.



Possible Nuclear Weapons Research

The IAEA is also investigating several activities and documents which suggest that Iran may be attempting to develop nuclear weapons.

Uranium Casting Document

ElBaradei reported in November that Iran has turned over a document detailing the "procedural requirements" for reducing uranium hexafluoride to "metal in small quantities." The document also discussed the "casting and machining of enriched, natural and depleted uranium metal into hemispherical forms."

This revelation has generated additional concern about Iran's nuclear program because shaping uranium in such a fashion is used in developing explosive cores for nuclear weapons. According to an EU statement to the IAEA Board  of Governors, "Such a process has no application other than the production of nuclear warheads."

Whether the document is evidence of a previously unknown Iranian capability to develop nuclear weapons is unclear. Iran has previously acknowledged that it was offered equipment for casting uranium but maintains that it has never received any such equipment. Iran claims that the document had been "provided on the initiative of the procurement network," rather than at Iran's request.

Activities at Parchin Military Complex

According to ElBaradei's November report, Iran granted IAEA inspectors access to Iran's Parchin military complex Nov. 1. The visit was the inspectors' first since January 2005. The inspectors "did not observe any unusual activities in the buildings visited," but the IAEA is awaiting the results of environmental samples taken during the visit before assessing whether Iran conducted any nuclear activities there.

The United States and the IAEA have both expressed concern that Iran has been testing conventional high explosives at Parchin for use in an implosion-type nuclear weapon.

The report also says that the IAEA wishes to "undertake additional visits" to the site but does not say why. However, a State Department told Arms Control Today that the agency may still have "suspicions" about Iranian activities at the site. The official also confirmed a November Agence France Presse report that the inspectors saw a high-speed camera during their visit. Such cameras can be used to monitor experiments with high explosives, such as those used in an implosion-type nuclear weapon.

Activities at Lavizan-Shian Physics Research Center

ElBaradei reported in November that Iran had still not cooperated with the IAEA's investigation of a physics research center that operated between 1989 and 1998 at a site called Lavizan-Shian that had been connected to the Iranian Ministry of Defense. However, Agence France Presse reported Jan.27 that Iran will allow IAEA inspectors to visit the site.  

Iran razed the site in late 2003 and early 2004 - a decision that raised suspicions that Tehran might be trying to cover up evidence of undeclared nuclear activities.  However,   ElBaradei reported in September that Iranian provided information consistent with the government's explanation for this action. (The razing of the site was carried out by Tehran's municipal government, Iran says. )

Nevertheless, the IAEA still wishes to take samples from a trailer which had been located at the site and contained dual-use nuclear equipment.  The agency also wants to interview Iranian officials who had been involved in the center's efforts to obtain equipment related to uranium enrichment.

Polonium-210 Experiments

The IAEA has not been able to resolve residual uncertainties regarding Iran's experiments involving the separation of polonium-210 - a radioisotope with limited civilian applications that can help trigger a nuclear chain reaction in certain types of nuclear weapons. Iran claims that these experiments were not for nuclear weapons, but   ElBaradei reported in November 2004 that the IAEA is "somewhat uncertain regarding the plausibility" of Iran's denial because the civilian applications of  polonium-210 are  "very limited."