Nuclear Weapons

Increased Safeguards at Natanz: What Does It All Mean?

08.28.09 | 9 min read | Text by Ivan Oelrich

by Ivanka Barzashka and Ivan Oelrich

A much anticipated IAEA report on Iran’s nuclear activities was leaked today.  The report indicates that, among other things, Iran has conceded to additional safeguard at Natanz.  This is a welcome development but occurring amidst a contested Iranian election, European threats of increased sanctions, continuing oblique hints of Israeli military action, and US talk of cutting off Iranian gasoline imports if nuclear talks are rejected.  How important are these increased safeguards? Do they represent a change of course for Iran?

Current IAEA Safeguards in Iran
IAEA safeguards ensure that no country with a peaceful nuclear program will use that technology to develop a nuclear weapon.  Specifically, safeguards provide credible assurances that fissile material is not being diverted from declared nuclear facilities.  In accordance with Iran’s Safeguards Agreement, IAEA inspectors monitor any facilities that have nuclear material “of composition and purity suitable for fuel fabrication or for isotopic enrichment.”  This includes the conversion plant in Esfahan, where yellow cake is converted to UF6, and the uranium enrichment facility in Natanz, where UF6 with natural concentrations is further enriched to concentrations suitable to fuel a commercial light water reactor.  Uranium mines and ore processing facilities are not monitored.  If Iran ratifies the Additional Protocol, then the IAEA will have access to all parts of the nuclear fuel cycle.

The safeguards objective is to ensure that, if a significant quantity (SQ) of material (that is, roughly enough to make a primitive bomb, in the case of highly enriched uranium, about 25 kg) is diverted, then the diversion will be detected within a certain time.  In the case of Iran, the IAEA guarantees detection within one month of diversion of one SQ and a high probability that they can detect much smaller diversion.

Safeguards at enrichment plants are mostly based on material accountancy, which confirms that declared material in a facility is not secretly diverted. Safeguards start with an initial report by Iran of all nuclear material that is subject to safeguards, supplemented by design information of the facilities where this material is contained.  This information is confirmed by the IAEA during design information verification (DIV).  This information is used to identify general information about the facility (location, capacity, throughput) , as well as strategic points relevant to material accountancy (locations where key measurements are made and inventory locations).

The latest IAEA report (GOV/2009/55) states that Iran has not yet implemented early provisions of design information in accordance with the revised Code 3.1 of the Subsidiary Arrangements General Part, which would require Iran to notify the agency of the construction of new facilities or modifications to existing ones as soon as such a decision has been authorized by the government or the plant operator.  The original agreement required Iran to submit such information no later than 180 days before the introduction of nuclear material into the facility (GOV/2003/40).

Based on these data, the IAEA and the Iranians then agree to the locations for containment and surveillance measures. Containment measures verify the physical integrity of an area or storage container. For example, this is done by placing seals on uranium cylinders under autoclaves.  Surveillance cameras are placed at key locations to record activities at the facility ensuring that no unauthorized movement of nuclear material occurs.  In addition, the cameras may confirm that, for example, the Iranians are making changes in the connections among centrifuges.  Re-piping a cascade would be one of the ways to produce highly enriched uranium.  The images from the cameras are periodically downloaded by IAEA inspectors. Camera cases are designed to reveal any attempt to tamper with them between inspections.

Iran submits reports to the Agency on uranium inventories and material flows.  Inspectors verify this information during on-site inspections by comparing declared amounts to Iran’s daily operating records.  Under the Safeguards Agreement, inspectors have the right to unannounced inspections.  In Iran, 24 inspections are done per year, half of which are unannounced.  Furthermore, inspectors perform physical inventory verification (PIV) once a year and have the option of interim inventory checks as well.  A PIV is a kind of super inspection in which storage containers are weighed to determine actual quantities of uranium at each enrichment stage and samples are taken to confirm enrichment levels.

Increased Safeguards: Two Components
Beefing up safeguards at Natanz is not a sudden gesture of Iranian cooperation with the IAEA.  The changes are not drastic and are consistent with the current Iran-IAEA Safeguards Agreement.  Safeguard changes are in response to accounting problems and Agency requests already laid out in the last two IAEA reports issued in June and February this year.

Part of the enhanced safeguards will be improvements in Iran’s own inventory estimating.  There was great brouhaha when the results of the November 2008 PIV were released in the Agency’s February 2009 report, revealing more uranium than the Iranians had declared.  Several times in the press and elsewhere, this was described as the IAEA “discovering” Iranian uranium when, in fact, it simply revealed that Iran’s ability to estimate its own throughput was inadequate.  FAS wrote a blog on this issue.

The changes are due, in part, to “the increasing number of cascades being installed at FEP” and “increased rate of production of LEU at the facility” (GOV/2009/35).  The June report states that containment and surveillance measures need to be improved “in order for the agency to continue to fully meet its safeguards objectives.”


Iran is having problems with enrichment product estimation


Improving Accounting
The IAEA has been insisting that Iran improve its own inventory control to make its declarations more credible.  Between PIVs, IAEA inspectors base their reports on Iranian logbook data of how much material has been put through the machines and Iranian calculations of capacity.  Iranian scientists do not have precise measurements of total production because some cylinders of UF6 are still connected to the cascade output, partially full, and cannot be weighed.  Because filling a cylinder with enriched uranium takes a long time, Iranian engineers have developed an algorithm to estimate how much uranium has been enriched and is in each cylinder.

There have been two PIVs at Natanz – one in November 2008 and in December 2007.  Iran started putting up machines in February 2007, so the first PIV reported only small amounts—75 kg—of  product (GOV/2008/4).  There were no reports of material enriched prior to the 2007 PIV.  Therefore, the first real comparison between Iranian logbook data and IAEA physical inventory results was in February 2009, when the report with the 2008 PIV came out in public.  It was clear that the algorithm estimating the amount of feed was very good, because logbook results matched IAEA’s findings.  In the case of the product, this was not so.  There was a 209 kg difference between Iranian logbook data and the results of the PIV, which amounted to about a third increase in product as declared previously.

Problems with Iran’s mass spectrometer – the device that measures the concentration of U-235 or the enrichment of the UF6, have also been reported. This would account for any differences between Iranian overall product enrichment measurements and what was recorded by the Agency.

An additional explanation cited in today’s report is the uncertainty in the amount of UF6 in cold traps.  Cold traps are cryogenic traps that hold the output of the vacuum pumps, which are used to maintain the vacuum inside the centrifuge casing and collect small amounts of uranium gas leaked through the centrifuge rotor shaft.  The amount of material contained in the cold traps is measured only by heating them up and cleaning them out so they are missed from day-to-day inventory control.  The report states that a difference of 538 kg could result from “mainly a hold up in the various cold traps,” and that such a large amount of material is “not inconsistent with the design information provided by Iran” (GOV/2009/55).

Containment and Surveillance Changes
An increasing enrichment capacity requires additions to existing safeguards, according to the June IAEA report. The FEP design information shows that the plant is divided into two cascade halls:  Cascade Hall A and B. Cascade Hall A has 8 units. As of the end of May 2009 one unit (A24) was completed. About a third of the total capacity of Unit A26 was operational, while another third had been installed, but operating under vacuum.  In other words, as the number of centrifuges increases and the operating area of the plant increases, the IAEA needs more monitoring assets on the ground just to stay even.  In addition, the IAEA is calling on Iran to address long-standing problems with their own inventory accounting.

IAEA Surveillance EquipmentPart of the enhanced IAEA monitoring capability may simply be more efficient use of current assets, such as surveillance cameras.  Standard practice at other enrichment plants is to construct the entire enrichment plant and only upon completion begin feeding the machines with UF6.  In contrast, Iran starts up each cascade of 164 coupled centrifuges as it is completed.  Thus, at the Natanz facility, there is an ongoing process of installing new centrifuge cascades in the same hall where previously installed machines are already operating.   Elsewhere, common practice is to have IAEA surveillance only in storage areas, keeping an eye on the seals on UF6 cylinders to make sure they are not tampered with.  In Iran, this is more of a problem, since new centrifuges are continually coming on line.  In theory, output of new cascades could be diverted.  This is why Iran has agreed to put surveillance around the cascade area as well.  For this to be affective, the cameras need to be able to have a clear view of the technicians to make sure that they are not removing nuclear material. This was less of a problem in the past since there were few cascades, but this is changing with the increase of plant throughput. As construction takes place at several units at once, inspectors have problems monitoring who is coming and going, especially since some new units may be out of view camera in their original positions.

A normal centrifuge plant requires very little personnel presence in the production areas.  The numerous workers installing centrifuges adjacent to the production area complicates the IAEA monitoring.  For example, Iranian attempts to change the piping on existing machines could be hidden within other, permissible, construction work.  If the operating machines were isolated from the construction, even by a simple partition, the additional activity of reworking the piping would stand out more clearly.  This would allow IAEA photo analysts to more effectively focus their efforts.  Iran may also accept some work restrictions, such as leaving equipment in front of a surveillance camera for some agreed length of time to allow its identification before moving it to another part of the plant.  Iran continues to resist remote monitoring so data from camera are downloaded when inspectors arrive on site and it analyzed later.

Political Implications
Some have suggested that Iranian compliance with IAEA requests is a sign that Teheran is preparing the ground for negotiations.   Iranian officials themselves have stated that they are open to talks without preconditions and there was even a domestic proposal for an enrichment halt.  The statement was quickly corrected making Iranian intentions as ambiguous as ever.

From a technical perspective, we believe that Iranian concessions on enhancing safeguards at Natanz do no present a fundamental change nor do they cause Iran much inconvenience. The changes are proportionate with the continued build up in the number of centrifuges and failure to implement them would have soon amounted to a violation of Iran’s Safeguards Agreement.

We should not read much political significance into Iran’s acceptance of additional safeguards.  Whether Iran is cooperating with inspections because of, or in spite of, the threat of increased sanctions, their centrifuge program is continuing.  Indeed, cooperation with the IAEA helps to weaken international political support for sanctions against Iran because of its nuclear program.  We could say that Iran would rather have IAEA inspections than violate its Safeguards Agreement and suffer greater international sanctions, but we believe that agreeing to additional safeguards monitoring is not, by itself, an indication that Iran is willing to sit down at the negotiating table, let alone give up its centrifuge program.