Towards Enhanced Safeguards for Iran’s Nuclear Program

Iran’s controversial nuclear program has been front and center on the international stage for more than eight years. Despite negotiations, sanctions, and political tug-of-war, the United States and its allies have yet to tame Iran’s atomic phoenix. At the center of this nuclear standoff is Iran’s controversial uranium enrichment program and efforts to obtain full nuclear fuel-cycle capabilities. To alleviate concerns about the intended nature of these activities, the United Nations Security Council (UNSC) has demanded -through six resolutions – that Iran suspend enrichment activities as well as construction of a heavy-water research reactor. Yet, Iran has opted to pay no heed to these resolutions and despite numerous proposals from different sides, the stalemate persists.

Dr. Charles D. Ferguson and Dr. Ali Vaez, authored a FAS report (PDF) analyzing the outstanding issues regarding Iran’s nuclear program, and provide recommendations to the major stakeholders in this debate including Iran, the United States, Russia and the International Atomic Energy Agency (IAEA).

Additionally, the report proposes a multipronged approach to resolving this deadlock, including enhanced safeguards and positive-sum diplomacy with incentives for Iran and other aspiring nuclear states.

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Using Enrichment Capacity to Estimate Iran’s Breakout Potential

While diplomats and officials claim Iran has slowed down its nuclear drive, new analysis shows that Iran’s enrichment capacity grew during 2010 and warns against complacency as five world powers resume talks.

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New Fuel Deal with Iran: Getting Back to Basics

by Ivanka Barzashka

After a year-long stalemate, Iran and the P5+1 seem to have agreed on a day for holding political talks – December 2. Iran’s Foreign Ministry spokesman confirmed last week that the meeting “will not include discussions on fuel swap” – the deal with France, Russia and United States, also known as the Vienna Group, to refuel the Tehran Research Reactor (TRR).

In principle, both Washington and Tehran agree that the fuel deal is still on the table, but the Iranians have been critical of the delay in setting a date for talks, which they interpret could be a lack of “willingness to enter peaceful nuclear cooperation.”

A successful fuel deal is a necessary condition for further engagement. However, circumstances have changed since October 2009, when the Vienna Group first made the fuel offer. Now, the State Department maintains that “any engagement [should be] in the context of that changed reality.” (Most of the Vienna Group’s outstanding concerns were listed in a confidential document to the IAEA, published by Reuters on June 9.)

However, the alleged terms of Washington’s new proposal seem to be muddled and will not have the claimed threat-reduction benefits (for a detailed discussion, see this Oct 29 post.) A technically-grounded analysis of what the fuel deal today can, cannot and ought to achieve is available in “New fuel deal with Iran: Debunking common myths,” published on Nov 2 in the Bulletin of the Atomic Scientists. Some highlights of these two assessments are provided below. (more…)

Iran Fuel Negotiations: Moving Muddled Goalposts

Moving Goalposts

by Ivanka Barzashka and Ivan Oelrich

A year ago, France, Russia and the U.S.—called the Vienna Group—proposed a deal in which Iran would ship out some of its worrying low-enriched uranium (LEU) in exchange for fuel for its medical isotope reactor, called the Tehran Research Reactor (TRR). These narrow technical discussions about the TRR were meant to serve as a confidence-building effort. The negotiations fell apart because of differences about timing of the exchange of material, but they may be about to restart. A year later, the facts on the ground have changed. These new circumstances may call for new negotiating terms, but changes have to make some sense. Calculations show that numbers recently floated by the State Department seem ad hoc and arbitrary and will not have the touted threat-reduction benefits.

On October 27, The New York Times reported that a senior U.S. official believed that the Vienna Group were “very close to having an agreement” on how the original fuel swap offer, made in October 2009, should be changed. One of the new terms would be an increase in the amount of LEU provided from 1,200 kg to 2,000 kg. The State Department explained a day later that “the proposal would have to be updated reflecting ongoing enrichment activity by Iran over the ensuing year.” Iran’s larger LEU stockpile changes Washington’s threat-reduction calculus, which ultimately undermines the confidence-building aspect of the deal.

Another new circumstance is Iran’s production of 20 percent enriched uranium, ostensibly to produce TRR fuel domestically. This is a worrying development because, compared to LEU, a stockpile of 20 percent material would cut by half Iran’s time to a bomb.

(more…)

Iran’s New Dual Track: A Challenge to Negotiations?

by Ivanka Barzashka and Thomas M. Rickers

Coaxed by Turkey and Brazil, Iran seems to be actively pursuing fuel talks. France, Russia and the U.S. (also known as the Vienna Group) claim that they, too, are interested in a deal, even as the U.S. and EU passed their own tougher sanctions against the Islamic Republic as part of a dual-track approach. Now Tehran may even be willing to address what was once the major hindrance to a deal: its 20 percent enrichment. Yesterday, Ali Akbar Salehi, Iran’s atomic energy head, said his country “will not need to enrich to 20 percent if [their] needs are met.” And yet on July 18, the Majlis passed a law requiring the government to continue 20 percent enrichment and manufacture own fuel, which is an apparent contradiction to negotiations for foreign fuel supply. Clearly, Iran is sending mixed messages. But does this mean there is an internal disagreement about nuclear policy? Or is Iran not serious about a fuel deal? (more…)

Will Iran Give Up Twenty Percent Enrichment?

by Ivanka Barzashka

In response to sanctions, Iran’s parliament adopted the Nuclear Achievement Protection Bill on July 18. Among other things, the law requires the government to continue 20 percent enrichment and provide fuel for the Tehran Research Reactor (TRR). Although this aspect of the legislation has largely fallen below the news radar, it raises important questions about the future of nuclear talks, which Iran has postponed until September as “punishment” of the West.

Iran says it is enriching to higher concentrations to manufacture its own fuel for the TRR, but a stockpile of 20 percent enriched uranium will reduce by more than half Iran’s time to a bomb (when compared to its current stockpile of 3.5 percent LEU). Now Iran’s higher-level enrichment may have become the connection between sanctions and a fuel deal that will hinder any engagement options. However, there is still time to explore resolutions to the impasse.

Ivan Oelrich and I have co-authored an FAS issue brief that traces the history of Iranian higher-level enrichment efforts in an effort to understand Tehran’s nuclear intentions. We were driven by the question: Will Iran, at this stage, give up twenty percent enrichment? Three distinct periods were analyzed: (1) from the beginning of 20 percent enrichment to the Tehran Declaration, (2) from the Tehran Declaration to the passing of UN sanctions, and (3) after sanctions. (more…)

Iran Beat Us to It.

Ivan Oelrich and Ivanka Barzashka

Back in October, when Iran put in a request to the IAEA for a new load of fuel for its medical isotope reactor in Tehran, the United States proposed that Iran ship out an equivalent amount of its low enriched uranium (LEU) in exchange. It turns out, purely coincidentally, that the amount of LEU equivalent to about 20-years worth of fuel for the reactor was almost exactly the amount that Iran would need as feedstock to produce a bomb’s worth of material. No one seems to question Iran’s right to purchase fuel, but the purpose of the swap was two-fold: to get the bomb’s worth of LEU out of Iran, which would have left Iran with less than a bomb’s worth of LEU feedstock, and to provide a seed for improved cooperation and trust. (more…)

Twenty Percent Solution: Breaking the Iranian Stalemate

by Ivanka Barzashka and Ivan Oelrich

Iran and the rest of the world are stalemated. Obama’s deadline for Tehran to address concerns about its nuclear program passed at the end of 2009, so the White House is moving to harsher sanctions. But the US is having trouble rallying the needed international support because Iranian intentions remain ambiguous. The deadlock includes negotiations on fueling Iran’s medical isotope reactor. With no progress on that front, Iran has begun its own production of 20-percent uranium for reactor fuel, a worrying development that could put Iran closer to a nuclear weapon. Yet, even while talk of sanctions escalates, Tehran says it is still interested in buying the 20 percent reactor fuel from foreign suppliers.

The Tehran Research Reactor (TRR) deal has backfired. The offer, to trade a large part of Iran’s low enriched uranium (LEU) for finished TRR fuel elements, was meant to abate the potential Iranian nuclear threat by reducing Iran’s stockpile of enriched nuclear material. By artificially coupling two distinct problems, re-fueling the TRR and Iran’s enrichment program, the US, France and Russia have given Tehran a reason, even a humanitarian one, to enrich to higher concentrations. The move to 20 percent enrichment will reduce by more than half the time needed for Iran to get a bomb’s worth of material. (more…)

The Revelation of Fordow+10: What Does It Mean?

by Ivanka Barzashka

According to a recent article by the New York Times, Western intelligence agencies and international inspectors now “suspect that Tehran is preparing to build more [enrichment] sites”. This revelation, according to the newspaper, comes at a “crucial moment in the White House’s attempts to impose tough new sanctions against Iran.”

However, these “suspicions” come months after Iran publicly disclosed such intentions. Tehran declared plans to build 10 additional sites on 29 November 2009, a couple of days after an IAEA Board of Governors resolution called on Tehran to confirm that it had “not taken a decision to construct, or authorize construction of, any other nuclear facility” and suspend enrichment in accordance with UN Security Council resolutions.

At the time, the Iran’s decision to construct more enrichment sites was widely dismissed in the West as an act of defiance and unlikely more than mere bravado. On 30 November 2009 the New York Times wrote that “it [was] doubtful Iran could execute that plan for years, maybe decades”. The same article referred to a high-ranking Institute for Science and International Security (ISIS) official claiming that taking the declaration seriously was “akin to believing in the tooth fairy” and that this effort would likely produce “‘one small plant somewhere that they’re not going to tell us about’ and be military in nature.”

In fact, a week before Iran’s original announcement, Ivan Oelrich and I argued in an article at the Bulletin of the Atomic Scientists that Fordow is likely one of many similar sites. A technical analysis of the facility’s planned capacity showed that, alone, it was not well-suited for either a commercial or a military function. The facility’s low capacity also undermined other strategic roles suggested by official and quasi-official Iranian sources – that Fordow is a contingency plant in case Natanz were attacked or that Fordow was even meant to deter an attack on Natanz. (more…)

Judging the Mood at the IAEA

by Ivanka Barzashka and Ivan Oelrich

The latest IAEA report on Iran has been widely touted as containing new evidence of Iranian weapons work and as a sign of the Agency’s new hard-line attitude toward the Islamic Republic under its new Director General Yukiya Amano. We believe the document has been seriously misrepresented in the media and elsewhere, which could have dangerous consequences. We made this argument in a recent op-ed in the Bulletin of the Atomic Scientists.

We should all bother to do a little reading and get our facts straight. If there was a case for new crippling sanctions or for bombing Iran before, the report adds nothing new. The February report contains no new evidence of Iranian weapons work that was not already in the public domain. There is no independent IAEA assessment that Iran currently has or has ever had a nuclear weapons program. This is also hardly the first time that the Agency has addressed outstanding questions pertaining to the possible military dimension of Iran’s nuclear program and has asked for Iran to respond.

Very limited space in our brief Bulletin op-ed did not allow us to address the issue of Amano’s allegedly new tougher tone. The February document, being Amano’s first, has been subject to an exegesis to discern potential attitudes from the director and has been described by Western media as blunt and even confrontational. Inside Iran, the issue of tone has been viewed by some as a “direct result of a change in leadership, and not the outcome of an unbiased evaluation.” (more…)

Flight Testing a Centrifuge

On 13 January, Ivanka Barzashka and I gave a briefing at the AAAS on our work regarding Iran’s uranium enrichment capacity. Joshua Pollack also gave a briefing, which he has described. Joshua’s analysis is thorough and interesting but I think I would use a different distinction than the “actual” and “nominal” values that he defines.

Pollack shows how the estimates of the capability of Iran’s centrifuge, the IR-1, have declined over time. That is intriguing but I worry that it makes the calculations that Ivanka and I and others have performed using data reported from International Atomic Energy Agency (IAEA) on-site inspections seem like the next step in a series of similar estimates. They are not. There are two very different types of approaches being taken here. Here I present an analogy that I think might make the differences clear. (more…)

Response to Critiques Against Fordow Analysis

Our article “A Technical Evaluation of the Fordow Fuel Enrichment Plant” published in the Bulletin of the Atomic Scientists on November 23 and its technical appendix, an Issue Brief, “Calculating the Capacity of Fordow”, published on the FAS website, have sparked quite a discussion among the small community that follows the technical details of Iran’s program, most prominently by Joshua Pollack and friends on armscontrolwonk.com and by David Albright and Paul Brannan at ISIS, who have dedicated two online reports (from November 30 and December 4) to critiquing our work.

Before addressing the arguments and exposing the fallacies in ISIS’s critique directly, we strongly encourage interested parties to read our Issue Brief, in which we have presented our reasoning, calculations, and assumptions in a clear and straight-forward way that we believe anyone with some arithmetic skills and a pocket calculator can follow and reproduce. We published a quick first version of our Issue Brief on 1 December. The 4 December ISIS rebuttal was based on the first Issue Brief. We published an expanded version of the Issue Brief on 7 December. The second version adds to the first version, but everything in the first brief is also in the second version. The second version includes additional examples and further details on how we carried out our calculations (as well as cleaning up some formatting, for example, all the tables in the first version were in different formats, the revision at least looks much prettier). References to equations and page numbers below pertain to the second revision.

In our Bulletin piece, we concluded that Fordow is ill-suited for either a commercial or military program and we speculated that it would make most sense if it were one of several facilities planned. The latter conclusion has been de facto supported by Iran’s recent declaration of 10 additional planned enrichment sites. Although ISIS explicitly states that our assessment of Fordow is unrealistic, the authors are not clear what their broader argument is. They seem to imply that Fordow alone is sufficient for a viable breakout option, which in the context of our Bulletin article would make Iranian intentions clear-cut but would, however, undermine the need for additional facilities.

Albright and Brannan state that we “appear to assume” that Fordow would perform worse than Natanz. Quite the contrary, we state clearly in our Issue Brief that “We use well- documented, publicly available data from official IAEA reports and one assertion: The best estimate of the near term capacity of the Fordow facility is the most recent capacity of the Nantanz facility, scaled by size.” In the December 4 ISIS report, this statement is corrected to say we “significantly underestimate the performance of the Natanz facility.” The basis of their argument is that our calculation of the effective IR-1’s separative capacity of about 0.44 kg-SWU/yr, lower by a factor of three, four, or more than previously published estimates (see Table 1 of the Issue Brief), is not characteristic of and seriously underestimates Iran’s capabilities. We argue that previous speculations on the separative capacity of the IR-1 simply cannot explain IAEA data on the actual performance of IR-1 cascades at Natanz, which we consider to be the only credible open-source information available.

Argument #1: Adopting Ad Hoc Values

Expert guesses on the IR-1 separative capacity vary greatly, as illustrated in Table 1 of our Brief. For example, since 2006 Albright continuously sites values in the 2 to 3 kg-SWU/yr range, which are either not referenced or are attributed to untraceable sources (e.g. “senior IAEA officials”, “former Urenco official”). The lowest value that Albright has cited was in a footnote on his prepared statement for the Foreign Relations Committee in 2006, which is 1.4 kg-SWU/yr, based on calculations of a 164-machine cascade described in an Iranian official’s interview (this number is consistent with Garwin’s estimate using the same data). Albright characterizes the 1.4 value as “relatively low output” and this number is never used in breakout scenario estimates. In the same footnote, he calculates a higher capacity of 2.3 kg SWU/yr based on Aqazadeh’s ballpark figures on the performance of the total planned 48,000 centrifuges. Since then, the most recent and most widely referenced value for the separative power of an IR-1 that ISIS uses in breakout assessments is 2 kg-SWU/yr. When given the choice between a higher value attributed to unnamed sources and values he calculates himself, Albright consistently chooses the higher values. This is especially misleading when dealing with weapon production scenarios, which evaluate what Iran can currently achieve.

However, in their critique of our Bulletin article, Albright and Brannan adopt significantly lower values for the separative power: 0.6-0.7 kg SWU/yr (which they say is “undoubtedly too low”) and 1.0-1.5 kg-SWU/yr (which they say is “reasonable for new IR-1 centrifuge cascades”). They do not explain their reasoning for the latter value, except that the upper boundary is close to “Iran’s stated goal.” Perhaps, the authors are referring to Albright’s 2006 estimate based on the Aqazadeh statement, but now pick the lower value of 1.4 kg-SWU/yr that Albright had calculated but dismissed. Although Albright and Brannan do not reveal the data or go through the calculations for their former value, they do allude to their method, which we will discuss below.

The authors arrive at the 0.6-0.7 kg-SWU/yr based on “the average output over nine months in 2009.” We believe that even this “undoubtedly too low” value has been miscalculated. There are two major sources of difference with the FAS 0.44 kg-SWU/yr value: (1) ISIS uses Iranian logbook data, which does not account for the hold up of material while FAS uses independently calibrated data in the IAEA reports, (2) ISIS does not account for the change in the number of machines in the 9 month period cited (we believe ISIS was referring to 31 January to 30 October 2009). On the other hand, FAS uses the values of independently recorded data (unfortunately, you have to look for them in the footnotes of the IAEA reports) and accounts for the holdup as described in our Issue Brief. In addition, we look at data since the last IAEA physical inventory in 2008, from 18 November 2008 to 30 October 2009 (the entire period for which calibrated date is available).

Iranian logbook data have been shown to slightly underestimate the amount of feed and more significantly overestimate the product. Essentially, Iran is putting more uranium in their machines and less enriched product is coming out than their material accounting algorithm shows, which effectively means that separative power calculated with Iranian logbook data is expected to overestimate the actual effective separative power per machine. This is why indendently calibrated data, if IAEA physical inventory data is not available, provides a more realistic estimate.

Albright and Brannan take an average of enriched product as reported by Iranian logbook estimates from February to October 2009 (an overestimated value), then they simply divide by the number of months to obtain a monthly average, also ignoring the fact that the number of machines varies from month to month. ISIS does not consider the amount of feed that has been reported to enter the cascades under the same set of data, but simply adopt 0.4 percent as the concentration of the waste stream. Although that number is indeed present in a footnote in IAEA reports (GOV/2009/35), it is not the overall concentration of the waste, but shows that particles of depleted uranium “down to 0.4% U-235 enrichment” have been measured. The difference between the ISIS lowest estimate and the FAS estimate is not as significant as the fact that Albright and Brannan dismiss the effective capacity of the IR-1 altogether.

Argument #2: Iran operates fewer machines when the IAEA is not looking

The number of centrifuges in the period is not only a difference between ISIS and FAS’s calculations but is also Albright and Brannan’s basis for dismissal of a smaller number altogether. The “number of centrifuges used in the derivation is from IAEA safeguards reports and exceeds the quantity of those centrifuges that are actually enriching.” In personal communication with Scott Kemp (as posted on Pollack’s blog), Albright has also speculated that cascades are not being operated continuously. This makes little sense. Do the Iranians wait until inspectors arrive to turn on their machines? (If this is so, then our problem with Iranian enrichment can be solved quite easily: just stop inspections and Iran will stop enriching altogether.) Additional reasons given in a recent Albright and Shire analysis published in Arms Control Today include: Iran is keeping cascades in reserve in case of cascade failures or if it decides to “produce higher enriched uranium” or Iranian experts are focusing on getting Fordow running. All of these arguments seem weak. In the November 30 report, ISIS make yet another conjecture –“a significant fraction of these 4,000 machines are likely also not enriching or are broken.” As far as we can tell, the ultimate basis for this claim is that otherwise ISIS’ higher per machine capacity does not make sense. However, we discuss the one bit of numerical evidence Albright and Brannan provide for their speculations below.

Based on IAEA reports, changes in the number of machines from 7 November 2008 to 2 November 2009 increases by only 10 percent or so; thus, even if we assume the minimum number of machines for each reporting period, instead of taking averages, the SWUs per machine will increase from 0.44 to 0.47, which of course, has a negligible effect on breakout scenarios. For the ISIS argument to become important, we have to believe that half or more of the machines reported by the IAEA to be operational in fact are not.

Moreover, remember that the basis of our argument is that recent performance at Natanz is the best predictor of near-term performance at Fordow. ISIS not only rejects our calculation of Natanz performance but rejects our assertion about it being the best predictor of Fordow. The implication of the ISIS critique is that, while there might be severe problems at Natanz, these will not be repeated at Fordow. This may or may not be true. Perhaps the centrifuges at Natanz perform poorly and are very unreliable and Iran has figured out all those problems and will only install 2.0 kg-SWU machines at Fordow (although we have no hard evidence that IR-1s of that capacity exist). Alternatively, perhaps there are systematic problems with centrifuge production and cascade operation and this is the best the Iranians can do in the near-term. Our assertion hinges on Iranian improvements being incremental and evolutionary and on not seeing dramatic, revolutionary improvements at Fordow. If this is not true, then our assertion for Fordow is wrong, but our estimates of Natanz’s capacity would still be correct.

The ISIS paper presents an additional argument to show that per machine capacity was increasing: daily average enrichment stayed constant at 2.75 kg of low enriched UF6, while the number of centrifuges dropped from 4920 to 3936. (There is the problem that we will set aside for the moment: Either the IAEA data are suspect or they are not, but one should not dismiss them in one case and base arguments on them in another.) We are back to estimating average number of machines per given period. We have three data points: 31 May – 4920 machines operating, 12 August – 4592, and 2 November – 3936. We agree with ISIS here: From 31 May to 12 August the average daily enrichment is about 2.8 kg UF6 (according to Iranian logbook data, not calibrated measurements) and similarly about 2.8 kg UF6 from August to November.

However, there are several problems with this argument. First and foremost, it depends on Iranian logbook data, which has been demonstrated to be inaccurate (plus, of course, IAEA inspection data that ISIS tells us is unreliable). Taking averages for the number of machines operating in each period and a concentration for the product of 3.49% (as the 2008 PIV), we get a slight decrease from 0.51 kg-SWU/yr (18 November 2008 to 31 May 2009) to 0.46 kg-SWU/yr (31 May to 31 July), followed by a jump to 1.0 kg SWU/yr per machine (31 July to 30 October), that is, a sudden doubling, according to Iranian logbook data. However, if we look at the independently calibrated measurements, the increase is only from 0.43 (18 November 2008 to 2 August 2009) to 0.49 kg SWU/yr (2 August to 30 October 2009). Also, note a negative holdup for August-November 2009; this could mean that the Iranians have started feeding the leaked material back into the cascades and are salvaging some of the lost separative work. Interestingly, if you look at the feed data, the feed went up slightly (from 30.4 kg UF6 per day to 31.05 kg UF6 per day, based on Iranian logbooks) as the number of machines went down, suggesting that the limiting factor is the amount of feed material. Finally, we do not know the enrichment concentrations definitively for those short periods. For example, a shift in enrichment from 3.5% to just 3.8 % would, by itself, account for all of the difference in separative work. Therefore, the ISIS numerical example is not indicative an increased per machine capacity.

We believe the lesson here is that short term logbook data are not reliable. Over time, an overestimate during one period will balance an underestimate in another and we will get closer to actual values but on short time scales we need to be wary of Iranian self-reporting. We concede, whenever we are given the choice, we rely on measurements conducted by IAEA on-site inspectors rather than Iranian logbook entries.

Argument #3: Misrepresenting the FAS Calculation

Albright and Brannan have succinctly expressed the basis of their critique: “We were unable to understand the problems in the FAS calculation.” On this point, we agree wholeheartedly.

Here is their argument according to the second paragraph of their 4 December posting: (1) They use our separative work number of 0.44 kg-SWU/yr to calculate what we would predict to be the output of Natanz; (2) This number turns out to be about half of what Natanz is actually producing; (3) QED, our separative work number must be wrong.

But part of their input data is that “[t]he authors also assert that the tails assay at Fordow should be 0.25 percent” when we never say any such thing (we do show example calculations using low, that is to say, global industry standard, tails assay). In fact, we calculate the tails assay at Natanz as 0.46%. Indeed, in the very next paragraph, they say that “FAS appears to have forced a U-235 mass balance by adjusting the tails assay in Table 2 in their assessment to 0.46 percent as a way to get the masses to match. But the situation at Natanz is quite complex.” On this point, we admit we are guilty as charged. When they say we “forced” the tails assay, what they mean is that we used the mass balance equation. And if the laws of conservation of mass do not apply in Natanz, then we concede that the situation there is quite complex indeed. (And, moreover, no calculation that anyone could make would be useful even in theory.)

Albright and Brannan are more specific: “For example, calculating the mass balance on the uranium 235 (uranium 235 in the feed should equal the uranium 235 in the product and tails) is not possible based on the available information. This requires assigning values in a formula that are impossible to substantiate.” Going to equation 5 on p. 8 of the Issue Brief and following the references, the reader can see that all of the values on the right hand side of the equation appear in IAEA reports. (And presumably as an alternative to “assigning values in a formula that are impossible to substantiate,” we would do better to accept values credited to “senior IAEA officials.”) If one uses our actual tails assay rather than the incorrectly asserted tails assay and the proper number of centrifuges and the difference between Iranian logbook data and actual IAEA measurements, all of the differences disappear. (As they have to, since we calculated the 0.44 kg-SWU/yr value in the first place based on these same numbers.)

In the end, an important scientific principle has been demonstrated here: if one takes several variables from one of our examples and several more variables from a separate example and combines them randomly, nonsense results.

Argument #4: ISIS Is Right Because the White House Says So

The most compelling support for the ISIS estimate that “using 3,000 IR-1 centrifuges, and starting with natural uranium, Iran could produce enough weapons-grade uranium for one bomb in roughly one year” that the authors give is that it is similar to the White House September 25 briefing statement that Fordow is capable of producing HEU for one to two bombs a year. First, this is a classic example of argumentum ad verecundiam – we are not about to accept White House numbers without checking their math. Moreover, it must be clarified that the US government’s statement is fairly vague and does not give details on this assumed breakout scenario (whether HEU is enriched from LEU or natural uranium and whether a crude or sophisticated weapon is assumed). What the government said was:

“[..] if you want to use the facility in order to produce a small amount of weapons-grade uranium, enough for a bomb or two a year, it’s the right size. And our information is that the Iranians began this facility with the intent that it be secret, and therefore giving them an option of producing weapons-grade uranium without the international community knowing about it.”

Let’s focus on paragraphs 6 and 7 from the November 30 ISIS report. In paragraph 8, the authors state that the White House scenario is unlikely to assume a breakout scenario using low-enriched uranium, since such a diversion would be likely discovered because LEU would have to be sneaked out of Natanz, which is under IAEA safeguards. They interpret the White House statement that weapons grade uranium would be enriched “without the international community knowing” means that this scenario would necessarily involve enrichment of natural uranium to HEU levels. But it must be noted that such a scenario would require a secret conversion facility as well, since the conversion plant at Esfahan is also under safeguards.

In paragraph 7, Albright and Brannan critique our assessment for “appearing to assume” that breakout scenarios considered depend on “activities not being discovered”, in apparent contradiction to their assumption in paragraph 6, that emphasized the importance of the clandestine function of Fordow. ISIS further argue that if Iran was “breaking out,” Fordow would likely sustain military attack better than Natanz. Our Bulletin argument was this: if Iran’s HEU production was likely to be discovered (such as if a diversion from Natanz were detected), speed is of the essence. They may be better off kicking out inspectors and going full-speed ahead at a facility such as Natanz with a large capacity, rather than proceeding with an option would take a year or more at Fordow. If Fordow’s capacity was significantly increased or if there were other similar facilities, this judgment may change.

Conclusion

As we have shown ISIS’ critiques of our Bulletin analysis and its underlying technical assessment are completely unsubstantiated. First, their track record of using higher vaguely referenced values and dismissing values based on physical data and their own calculations, just because they are inconsistent with their previous assessments, is troubling. Second, they greatly misportray FAS’ technical argument, which is clearly described in our Issue Brief. Third, Albright and Brannan seem to pick and chose assumptions to suit their argument at hand: on one hand they assert that IAEA data do not provide a good account of what is going on at Natanz to advance one point, but at the same time site these data to support other points.

Overall, it is hard to see the bigger argument that ISIS is making by attacking our premise regarding Natanz’s capacity (and consequently Fordow’s), but not specifically our conclusions on Iranian intentions vis-à-vis Fordow. It seems Albright and Brannan are interested only in defending their use of a higher separative capacity by attempting to undermine our argument. They do not discuss how our Bulletin conclusions would change if their shorter time estimates were correct, but simply dismiss our analysis altogether.

Ultimately, the reason we engage in discussions over these numbers is because we believe that overestimating Iran’s enrichment potential will provide us with a skewed perception of Tehran’s intent and strategic planning. It is indeed important to be able to make a realistic assessment of Iran’s current capacity and future potential. However, this is best done using neither Poisson statistics nor arguments of authority, but a good look at readily available hard data.

by Ivanka Barzashka and Ivan Oelrich

Our article “A Technical Evaluation of the Fordow Fuel Enrichment Plant” published in the Bulletin of the Atomic Scientists on November 23 and its technical appendix, an Issue Brief, “Calculating the Capacity of Fordow”, published on the FAS website, have sparked quite a discussion among the small community that follows the technical details of Iran’s program, most prominently by Joshua Pollack and friends on armscontrolwonk.com (on December 1 and December 6) and by David Albright and Paul Brannan at ISIS, who have dedicated two online reports (from November 30 and December 4) to critiquing our work. (more…)