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The International Atomic Energy Agency and Parchin: questions and concerns

The IAEA’s rationale for visiting Parchin

For nearly a year the already tense relations between the International Atomic Energy Agency (IAEA) and the Islamic Republic of Iran have been strained by a dispute over the IAEA’s request to visit a large military production complex located at Parchin, near Tehran. The request is part of the agency’s efforts to resolve questions about whether alleged Iranian nuclear activities have what IAEA Director General Yukiya Amano has called ‘possible military dimensions’. The agency’s concerns were summarized in a report submitted by Amano to the IAEA Board of Governors in November 2011. Iran has dismissed the allegations of clandestine nuclear weapon-related activities as being baseless and the products of fabricated and forged documents.

Currently, the IAEA is seeking permission to make a ‘transparency visit’ to a small compound, consisting of four significant buildings, at the sprawling Parchin complex. The agency says it has information from a member state indicating that Iran constructed a large steel chamber in one of the buildings for conducting high explosives experiments—some of which may have involved uranium—which could be associated with a secret programme to develop a nuclear explosive device. The IAEA has expressed concern that Iran has been taking measures that appear consistent with an effort to remove evidence of its past activities at Parchin that will ‘seriously undermine’ the agency’s ability to conduct effective verification when inspectors gain access to the building of interest.

Parchin testing site
The Parchin Military Explosives Factory covers about 40 square kilometres of desert and mountains with hundreds of buildings. Image credit: Google Earth, GeoEye


For its part, Iran maintains that the Parchin complex has been used solely for conventional military purposes, with no connection to nuclear material, and has already been adequately inspected by the agency. IAEA inspectors visited the Parchin complex in 2005 but did not ask to see the building where the explosives tests allegedly took place.

The dispute over the Parchin visit is part of a broader argument between the two sides over so-called modalities, that is, agreements setting the terms and conditions for the IAEA’s investigation of specific activities of concern. The main point of contention has to do with the sequencing of the questions the agency wishes to address. Iran insists that this had to be done in a pre-determined order; after agreed steps—such as a visit by the agency to Parchin—are taken to resolve each issue, the matter will be considered closed. In contrast, the IAEA prefers to address multiple issues at the same time, since many of the activities that the agency is looking into appear to be linked. The IAEA also emphasizes that since follow-up questions could be required to clarify specific issues if new evidence emerges, it cannot tie its hands in advance by agreeing to close the file. Iran in turn has complained that this raises the prospect of it having to answer endless requests from the IAEA.

The IAEA has an important role to play in Iran, specifically in monitoring declared nuclear materials in the country under Iran’s comprehensive safeguards agreement with the agency. This process is proceeding quite smoothly, with the IAEA reporting quarterly on Iran’s progress in uranium enrichment, reactor construction and other matters. If the deadlock over Parchin continues, it could contribute to an increasingly adversarial relationship in which Iran might seek to obstruct or impede the IAEA’s access to known nuclear facilities and thereby jeopardize the flow of information about its nuclear programme.

In addition, the dispute has already become a distraction for the negotiations between Iran and the five permanent members of the United Nations Security Council plus Germany (the ‘P5+1’). Success in these talks is the key to resolving the long-running controversy over the scope and nature of Iran’s nuclear programme; a visit to Parchin by the IAEA is a secondary issue.

One obvious question that arises is whether the current battle over the Parchin visit is really necessary. Iran’s activities since the IAEA asked for access to the site have undoubtedly been provocative and unhelpful. However, as the questions posed below are intended to highlight, a careful review of the evidence available to date suggests that less has been going on at the site of interest than meets the eye. The allegations that Iran carried out hydrodynamic experiments related to nuclear explosives in a large steel containment vessel there have questionable technical credibility. Moreover, recent reports picked up in the mainstream media may have misinterpreted unrelated construction or renovation work at the site as indicators that Iran was ‘sanitizing’ the site to remove evidence of uranium contamination. This suggests that the case for visiting the Parchin site—a matter on which the IAEA continues to insist—is not as clear-cut or compelling as some experts and officials portray it.


Parchin testing site
This tunnel complex c. 5 km from the Parchin test building is a far better approach for high explosive testing with uranium than a steel chamber, as Pakistani scientists learned in the 1980s. Image credit: Google Earth, GeoEye.

Does Iran need a large conventional explosion containment chamber to develop nuclear explosives?

Not really. Iran has been accused of building a large steel vessel in the suspect building at Parchin. The only public evidence of this is an extremely simple computer-aided design (CAD) drawing published in a news story that was based on information reportedly provided by an eyewitness. The drawing bears similarities to a drawing in a book about explosive chambers for making industrial diamonds. It is claimed that the author of the book, a former Soviet scientist named Vyacheslav Danilenko who was recruited to help Iran develop implosion technology, designed the alleged chamber at Parchin in the period 1999–2000. The chamber was supposedly installed in early 2000, so the timeline is obviously suspect (see below).

A chamber such as the one claimed to be in the building is neither necessary nor particularly useful for developing a first-generation nuclear weapon. Such development tests have normally been done outdoors for decades. If a large explosion is necessary at the final stage of development, this can be carried out in an underground tunnel much more cheaply and easily. (Pakistan took this approach in its own clandestine nuclear weapon programme in the 1980s.) There is a large new tunnel complex located about 5 km from the alleged test building but to date the IAEA has not shown any public interest in visiting it.


Exploson chamber drawing
A drawing of the alleged explosive testing chamber reportedly produced based on an eyewitness account.

What do we know about the alleged explosion chamber?

It was the next step in chamber development according to Danilenko’s plans. Implosion technology was originally developed for nuclear weapon design work and was later applied to industrial processes including making industrial diamonds. Such a chamber is necessary to contain the diamonds so that they can be recovered. A chamber is not necessary for nuclear weapons development. The explosives vessel, or chamber, is said to have been put in place at Parchin in 2000. This leaves no time for the fabrication of a 300-plus tonne chamber. For reference purposes the alleged chamber is about the same size and thickness as an early generation boiling water reactor pressure vessel, which few companies can fabricate.

An odd feature of the alleged chamber, not normally seen in conventional explosives test chambers, is a large concrete collar around a portion of it. This collar was supposedly designed to strengthen one end of the chamber and it also interferes greatly with experiments. According to one news report, the chamber was built at an oilfield equipment fabrication company. The collar would be necessary if it is real because the oilfield equipment fabrication company could not build a chamber so thick and strong with only a few months’ notice.

Would Iran need to do experiments involving uranium and conventional high explosives in a chamber if it wanted to develop a nuclear weapon?

There are a range of experiments involving explosives and uranium that a country presumably would conduct as part of a nuclear weapon development programme. Most of these are better done in the open or in a tunnel. They include basic research on neutron initiators using very small amounts of explosive and grams of uranium and on the very precise timing of a neutron initiator using a full-scale conventional explosion system and many kilograms of uranium. The alleged chamber at Parchin is too large for the initiator tests and too small for a full-scale explosion. If it exists at all, it is a white elephant.

Has Iran carried out any suspicious experiments?

The IAEA says that Iran did very complex experiments involving explosives and many fibre-optic detectors and possibly uranium. However, the IAEA says these experiments were not done at Parchin but rather 500 km away at Marivan. In any case, the experiments at Marivan described in great detail by the IAEA would not use uranium.

Can high explosive tests using uranium be detected later?

Yes. Uranium in an explosion will burn and produce a fine oxide powder. This is slightly radioactive and will persist for years, especially inside a chamber or a building, but also outdoors.

In 2008, IAEA inspectors travelled to a site in Syria, believed to be the location of an undeclared nuclear reactor, which had been bombed by the Israeli Air Force a year earlier. Syria had bulldozed the site and demolished a building there long before the IAEA team arrived. Inspectors found many man-modified uranium particles at the site, mostly in an adjacent building, which could be attributable to either natural uranium metal fuel for a reactor or natural uranium metal casings for a deep, earth-penetrating bomb.

What about the berm?

One notable feature of the Parchin site is the small earth berm located immediately south of the building alleged to hold the explosion chamber building. The IAEA discussed this feature in its November 2011 report, stating that, ‘The explosives vessel, or chamber, is said to have been put in place at Parchin in 2000. . . . A large earth berm was subsequently constructed between the building containing the cylinder and a neighbouring building, indicating the probable [emphasis added] use of high explosives in the chamber.’

The reason this berm could indicate possible use of high explosives in the chamber is because it is a shield. The only practical purpose of such a structure would be to shield the other two buildings closest to the testing hall from an unknown hazard. Because Parchin is largely an explosives factory there are many other berms within a radius of a few km. The berm in question at the alleged building is one of the smallest at Parchin and only protects a small angle of hazard. It is not a typical explosive protection berm and is equally likely to be a berm to stop a radiation beam such as from an industrial x-ray machine.

Has Iran demolished the building at Parchin that the IAEA wants to visit?

No. Some reports implied that Iran had destroyed the building, but this is incorrect. The IAEA claims that five buildings on this site have been demolished but this cannot be seen in satellite imagery. Iran did demolish a small outbuilding on the same site that appears to have been a garage. It was probably demolished to make way for a new road that is being built at the Parchin complex. Another small structure, probably a garage or material store was reported destroyed but is still in place in the latest satellite imagery.

The building of interest for the IAEA remains standing. However, it has been at the centre of a refurbishment effort that might include attempts to clean it inside.


The alleged Parchin test building
The vicinity of the alleged test building. The red area is the 25 hectares that are associated with earth moving. The yellow area is the portion immediately adjacent to the building. The green area is where there would be contamination as well if uranium had been used there. Image credit: Google Earth, GeoEye.


Do IAEA collectors usually collect soil samples to detect traces of uranium experiments?

Hopefully not! All soil contains significant amounts of uranium. The process used to detect trace quantities of tiny particles of man-made uranium is severely hampered if there is natural soil in large quantities compared to a tiny trace of uranium from human activities. The IAEA knows this from inspections in Iraq and the experience in Syria. The agency will collect its samples inside the building at Parchin and on any equipment there.

Is Iran bulldozing the site and covering it with earth to prevent the IAEA from detecting uranium contamination?

Iran has engaged in large-scale bulldozing operations on about 25 hectares near the Parchin building. This includes the bulldozing of old dirt piles to level a field 500 metres north of the building of interest. However, there has been no such activity in the area west of the building, except for removing some parking pads within about 10 m of it. The fact that the building’s immediate vicinity has been largely untouched on the west side strongly suggests that the purpose of the earth-moving operations was for construction and renovation work and not for ‘sanitizing’ the site by covering up contamination. In any event, the IAEA should not be collecting samples of dirt or dead vegetation to detect tiny uranium traces.


Roofteops of buildings at Parchin
Reroofing of two buildings is underway. Insulation material can be seen stacked above the top builidng. This is also a good image showing earth moving to the east of the main builidng while the rock area to the west is untouched. Image credit: Associated Press.

Did Iran tear down buildings while shrouding them under bright pink tarpaulins?

In the summer of 2012 Iran began major renovations at the site. Workers decreased perimeter security by tearing down fences, demolished one outbuilding and began renovation of two buildings. They covered both buildings with pink styrofoam insulation, which can be seen in Figure 5. One building is completely covered with insulation and the other is about 60 per cent covered. Raw materials can be seen on the ground nearby. The buildings were then reroofed and are at different stages of renovation even today.

American building during insulation
A US building in the middle stages of insulation. Image credit: <>.


The impasse over the Parchin visit has taken on a symbolic importance that is distracting attention from the IAEA’s efforts to address a range of questions about the scope and nature of Iran’s nuclear programme. The IAEA has invested considerable time and effort trying to persuade Iran to allow it to visit one building at the huge Parchin military complex. For its part, Iran has been less than constructive by refusing the agency access to the building at Parchin without negotiating modalities that would let the IAEA conduct its visit and report its findings. The bitterness and squabbling over Parchin, in which statements and conclusions have got out of hand, is not productive—and it impedes the IAEA’s main mission.

What is needed is a new approach. The IAEA is stretching its mandate to the limit in asking for access to a military site based on tenuous evidence. The UN Security Council should step in and negotiate a visit to Parchin by a non-IAEA international team. That team could include experts with much greater experience than the IAEA can deploy and come to technical judgements about the site. If nothing nuclear is found then the IAEA has no grounds for complaint. If something nuclear is found then the IAEA will be vindicated and will need to become seriously engaged in the follow-up investigation.