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In an unfortunately title article in Jane’s Intelligence Review (“Safir When Ready: Iran sets its sights on long-range capability”; sorry, its subscription only) I discussed why I interpreted pictures of the test-stand version of a Safir second stage as indicating Iran was developing a new advance in its missile program: a clustering of two engines that are gimbaled for thrust vector control.

In yesterday’s post, I discussed why eliminating the jet vanes could be used to lower the dead weight associated with storing the smaller amount of fuel required to produce the same change in velocity.

Today, I want to estimate how much dead weight is either saved or used up in the engines alone when you cluster them. (The last post in this series will try to put it all together and discuss how much Iran will have to improve its technology in order to get an ICBM capable of launching a nuclear weapon at the United States.)

This post might be excessively techno-wonkish but as an added bonus, for those of you who are willing to wade through the details, it should yield some interesting insights into the level of Al Samoud/SCUD/Nodong engine technology.

As can be imagined, a missile’s engines constitute a major portion of the “dead” weight contribution outside of the payload. Engine weights have, therefore, been a major area of research with much work going into reducing the weight per ton of thrust. A wonderful book, if you can get it, is Aerospace Vehicle Design: Spacecraft Design (vol. 2) by K. D. Wood. It basically covers every important aspect of designing missiles and spacecraft and, most importantly for this analysis, has a ton of empirically derived graphs. I’ve reproduced a couple of these below. Engine weight, including the turbopump and piping, as a function thrust is shown on the left while the turbopump weight alone is shown on the right.

I’ve added three points to the plot on the left: the Al Samoud II, the SCUD-B and the Nodong engines. The first two are based on actual measurements while I estimated the third, the Nodong, from an admittedly arbitrary curve that I drew using the Al Samoud and the SCUD points and the rough shape of the two curves surrounding it: the World War II range of rocket engines and the range identified as “Attainable Range, 1960-70.” Remember, this is a blog and not a refereed journal! (The book was published in 1964.) This “SCUD-family” of engines falls nicely between the two. Does that mean that the SCUD technology is worse than Western technology dating from the 1960s? Not at all! SCUDs were designed for rough handling and do not use the high energy fuels that the racehorses of the era, the space launch vehicles, did; namely cryogenic fuels. Both of these factors have the effect of increasing the engine weight per ton of thrust.

There have been a number estimates for the thrust of the Nodong/Shahab missile which can be used for estimating the engine/turbopump masses using the graphs above. I’ve used the thrust from a set of parameters for the Nodong originally published by Robert Schmucker in estimating the Nodong/Shahab/Safir 1st stage engine weight, including its turbopump and associated piping, as weighing 330 kg.

You can use the graphs above to do the same for your favorite missiles. Let me summarize a few of the weight combinations that I find most interesting:

*These are measured quantities. All others are estimates or derived from measured quantities.

So what does this tell us?

The Safir does not manage to save much weight (just 2 kg) by using a single SCUD turbopump as opposed to one turbopump for each Safir engine, assuming the turbopump is sized for the individual Safir engine. Iran might, however, save an addition 14 kg if they developed a new, single turbopump for the cluster of two engines. But would that be worth it, considering the time and resources they would have to devote to developing a new and unique turbopump? Obviously, Iran has decided it would not. I cannot help but agree with them. Perhaps when their space/missile industry has developed enough to afford the human resources to devote multiple teams to multiple turbopump design project they can. This points out one of the most important of scarce resources to any country just starting to develop new rockets: trained and skilled manpower!

We know now that Iraq was planning on using the airframe developed for the Al Samoud and stuffing a second Volga engine in it for a two engine cluster. (This possibility, which we considered very likely, was a crucial factor in why UNMOVIC proscribed the Al Samoud II.) Here too, the proliferator would have gained about 14 kg by developing a new, single turbopump for the cluster. Here too, the proliferator chose not to develop a new turbopump, again presumably because the resource costs for such development would have been too high. (Also, Iraq never did manage to develop its own turbopump!) On the other hand, a SCUD turbopump would be considerably overpowered for a two Volga engine cluster and would actually weigh more (142 kg vs. 120 kg) than having each engine retain its own turbopump, the course Iraq actually planned on using. Would Iraq have gained other benefits from using the Volga turbopump? Would it have been easier for them to balance the thrusts of the two engines by controlling the two turbopumps? Or would it be more difficult? Both, it seems to me, would have required considerable R&D but I would guess that a single turbopump would be easier. Of course, I could be wrong; thoughts, Wonk readers?

Finally, a cluster of four Nodong engines—such as has been reportedly used in the first stage of the Tae’podong II—saves well over 100 kg in weight if it uses a single turbopump developed and optimized for that configuration. Is that enough to justify a proliferator developing a new turbopump? Perhaps we will only know for certain when we start seeing images of that stage appear in public. We will put those weight savings in perspective when we compare the two strategies for developing ICBMs: stacking existing missiles one on top of the other vs. developing new airframes for existing engines. (I tend to think of these two paths as the North Korean path vs. the Iranian path, but perhaps I’m jumping to conclusions too much!)

I am postponing the fourth post in this series, which will consider the US estimates of Iran’s missile development program, until Monday to consider the discussion we have had on the Sejil.

Comment

Yesterday, I discussed the possibility that Iran was learning techniques that might help them utilize higher energy fuels such as UDMH and nitric acid. However, the evidence for such use is rather minimal. The case we examined yesterday was not very convincing and, while there is still room for doubt (see Jochen Schischka’s comments), I think that that the balance of the evidence still leans toward Iran utilizing kerosene/nitric acid combinations. What is know is that Iran is trying to improve its engines and get a higher specific impulse—a measure of how energetic the combination of propellant and engine is—regardless of what fuel it is using. (The technical definition of specific impulse is the thrust delivered by the engine divided by the weight of propellant burned per second.) While Iran’s efforts to do this are most obvious on the Safir’s second stage, it is possible that Iran is also taking the lead away from North Korea in improving the specific impulse of the Shahab/Nodong/Safir 1st stage as well!

People often forget that the design of the engine has a direct effect on the specific impulse and usually compare the theoretical specific impulses of various fuel and oxidizer combinations. If you simply compare these theoretical values for UDMH/nitric acid and RP-1/nitric acid (RP-1 is a kerosene-like fuel similar to the kerosene-based fuel the SCUD uses) you get a ratio of 276/268, in vacuum, and thus an increase of only 3% by going to the more energetic fuel. But the design of the SCUD engine, and in particular, its thrust vector control mechanism robs the propellants of a considerable amount thrust! Consider the images below, which show the jet vanes for the Iraqi Al Samoud II, the SCUD-B, North Korea’s Tae’podong 1, and Iran’s Kavoshgar 1 (which I assume are identical to those on the Shahab and the first stage of the Safir).

Note the differences in specific impulses, Isp, between the Al Samoud II and the SCUD-B. It is true that these two missiles use different fuels (the Al Samoud uses TEGA 2, aka Tonka, while the SCUD-B uses TM-184; both are hydrocarbons) and will certainly have slightly different base specific impulses. However, it is widely understood that the jet vanes on the Al Samoud II, for instance, rob the engine of as much as 5% of its thrust. This would account for just over 10 s of Isp! It is not too hard to imagine that the SCUD’s larger Isp might, in part, be due to its jet vanes covering somewhat less of the its nozzle exit area. (This, by the way, is what the subtitle of this post is all about.) I’d be interested if any of you out there (John?) wouldn’t mind calculating this effect from first principles.

What I find most interesting about this comparison is that the Iranian jet vanes appear somewhat smaller to me and are, perhaps, angled outwards so that they interact with more of the peripheral part of the exhaust than North Korea’s Tae’podong 1. Is this an indication that Iran has diverged from the Nodong missile it is reported to have imported from North Korea to optimize its thrust? If so, it is an another indication that Iran is leading the way among the so-called proliferating nations: Iran, Syria, North Korea, … in developing better missiles.

This improvement is, of course, a minor one since it still uses jet vanes to control the direction of the first stage’s thrust. But as I mentioned in yesterday’s post, it is more effective to improve the specific impulse of a missile’s second stage. This is exactly what Iran has done by developing a cluster of two gimbaled engines for the second stage of the Safir missile.

Until I started writing these series of posts, I wondered why Iran was putting so much effort into gimbaled engines as opposed to developing a new, higher energy-density propellant combination. Now, I think, we can see the answer. By eliminating the jet vanes, Iran has produced almost the same improvement in delivered thrust as it would get if it had switched to a UDMH/IRFNA combination. Of course, it would be best if Iran did both but doing both at once would significantly increase the development risk and it makes sense for Iran to take these challenges one at a time.

Increasing the effective specific impulse of its engines by removing the jet vanes implies that Iran can cut down not only on the volume (and hence weight) of propellant but also the amount of tankage or dead-weight of the tanks. The next post in this series, on clustering engines, will examine the change in “dead-weight” associated with clustering engines. It will also probably be one of the most techno-wonkish of all this series of posts and I apologize for that in advance.

Comment [5]

I thought I’d try an experiment in blogging: a five part series going into the details of Iran’s liquid-propellant missile development program; something I’ve been thinking about a lot lately. (The over-all title of the series is “Scaling Up the SCUD” but I don’t have enough room to put that in every time.) Iran’s missiles are one of the main threats the US sees on the horizon and, if your believe General Obering, the Director of the Missile Defense Agency, could attack the United States as early as 2010. But that will require a considerable advance in Iranian technology! Just how reasonable is that? I hope that by the end of this series, you will have a good idea of the technological challenges Iran would have to overcome to justify that concern.

Today’s topic of discussion is motivated by a close-up of the nozzle of a Shahab missile, the same sort of engine that was used on the first stage of the Safir launch August 17th, 2008. (The paint scheme of desert tan seems to indicate it’s a deployed Shahab as opposed to one of the “civilian” launches. Note that you can just start to see two of the four jet vanes to the lower left and right.) Some goop is smeared on the inside of its smallest diameter, the throat of the nozzle: What’s with the Goop?

The goop doesn’t completely seal off the throat, nor even make an appreciable change in its area so I think we can rule out functions such as keeping dirt and dust out of the thrust chamber as the missile is driven around the desert or temporarily increasing the “stay” time of the fuel during ignition. My current best guess is that it’s a wax-like substance that is used to temporarily close holes intended to “film cool” the nozzle.

To understand a possible explanation, let’s consider the startup process in a missile. First, several squibs, or small pyrotechnic charges, are fired at several places in the fuel and oxidizer lines to open up seals that keep them in the tanks before ignition. Simultaneously, a larger charge is ignited to produce gas to start the turbopump turning and sucking fuel and oxidizer down out of their tanks. This pump pushes the fuel (in the case of a SCUD) through the regenerative cooling system. That too deserves some explanation.

The rocket engine’s combustion process produces gases that are very hot, roughly 2700o C for a SCUD, and the combustion chamber needs to be protected against that heat. (Steel, by the way, looses all its strength at about 1000o C.) To do this, the Soviet designers made the combustion chamber with an inner liner and an outer shell with a small gap between the two. Fuel is pumped through that gap before it enters the combustion chamber, both cooling the inner wall and preheating the fuel before it is burned. A highly efficient system! But if the chamber generates too much heat—or if there are problems with the regenerative cooling system, say if bubbles form at an undesirably low temperature—another method of cooling must be introduced. A natural thing is to take some of the fuel as it is circulated through the gap and spray it though little holes in the inner shell to create an additional cool-gas barrier between the hot center and the steel walls. I don’t remember seeing any such holes on SCUD engines and I cannot find any mention of them in my reference material. Do any of you readers know?

Here is where the policy implication comes in. If Iran is ever going to make a real ICBM, it needs to switch from SCUD-type fuels to higher energy fuels. But you get considerably more than just an increase in thrust from using higher energy fuels! You can reduce the volume of fuel used and, hence, the dead weight of the missile; the structure of the missile. The advantages don’t stop there! Lower missile weights means you don’t need as much structural strength possibly enabling you to switch to lighter materials, such as aluminum. You get the picture. A relatively modest increase in specific impulse by going to UDMH and nitric acid will increase the range of the missile much, much more than you might initially think. The problem is keeping the engine cool!

Iraq tried to advance to the next higher energy level of fuel by using UDMH and nitric acid but the problems associated with that higher energy fuel caused a burn-through in the SCUD engine’s radiatively-cooled nozzle skirt 14 seconds after the burn was started. (Would the combustion chamber have burned through if the test had gone on longer? That is the question! Note, however, that I don’t say “higher temperatures.” In fact, UDMH and nitric acid actually have only a slightly lower combustion temperature than standard SCUD propellants but there is a lot more involved in cooling than combustion temperature. That’s why it’s called rocket science!) Let’s assume—we certainly haven’t proved it!—that the goop is covering film-cooling holes until after ignition. Do those holes indicate that Iran has the capability of cooling its engines more than Iraq was able to? Will they be able to jump to higher energy fuels and quickly make an ICBM? And if so, why are they messing about with SCUD-type fuel for the Safir second stage? After all, doesn’t it makes more sense to use a higher energy fuel in the second stage where reductions in dead weight really payoff?

Part 2 of this discussion will consider what development path Iran is known to be following with the second stage of its Safir missile. (See the detailed post by Jochen Schischka for an alternative view of the propellant used by the Safir. I remain firmly of the opinion that it used propellants like RP-1 and nitric acid; SCUD-type fuels.) Until then, I look forward to reading your comments!

Comment [5]

How about when half of it is liquid propellants? How about when it includes all of the deadweight—fuel tanks, turbopumps, and engines—associated with liquid propellant engines? How about when it makes no attempt to solve one of the major problems of solid-propellant technology: thrust vector control? Hi wonk readers! Jeffrey has kindly taken off my training wheels and let me be a guest blogger on his outstanding armscontrolwonk in my own right. I had thought I’d start my tenure here with a series of posts about Iran’s liquid propellant missile development program but I’m going to postpone that start until tomorrow. In stead, I thought I would weigh in on Iran’s solid-propellant missile. Ooops! I mean to say on their new liquid-propellant missile. Wait, that’s not exactly correct either. You know the one I mean; it’s the liquid-propellant missile with a solid-propellant motor in it. They call it the Sejil.

I’ve just come back from Croatia where the hotel’s internet was so flaky that I couldn’t do anything, so this post has been delayed by several days. I heard the news that Iran had launched a “two-stage, solid-propellant missile” with a range of 2,000 km literally as I was boarding the airplane on my way to London. I spent the entire flight wondering how I could be so wrong about the status of Iran’s solid-propellant development program. You see, there was no evidence that Iran had even experimented with thrust vector control (TVC) techniques suitable for solid propellant missiles. Graphite jet vanes, like Iran uses on its Shahab and its derivative missiles, corrode and fail very quickly in the high temperatures and corrosive environments associated with solid-propellant grains that use aluminum powder to boost their specific impulse. Fluid injection, like India used for the first stage of its SLV-3 (and the Agni I), requires considerable development both on static test stands with multiple degrees of freedom and flight tests on smaller missiles. The use of flexible nozzles also requires considerable R&D. None of which has shown up on Iranian short range solid-propellant missiles. Instead, they had seemed to be developing aerodynamic controls for these missiles instead of TVC. In particular, they have experimented with canards on some of their short range solid-fueled rockets; avoiding the entire TVC issue all together.

In contrast, and this was the really surprising thing, I think they used fairly large gimbaled engines to accomplish TVC for the Sejil. We know they are fairly large because the fuel and oxidizer tanks take up half of the first stage volume. The clincher that this was a largely liquid propellant missile, by the way, is the piping coming from the middle of what many supposed to be a solid propellant combustion chamber. Judging from the weld lines seen in other images of the Sejil, the missile uses over five tons of kerosene/nitric acid to power the four gimbaled engines in the first stage. (There is no indication that I can see that the second stage was anything other than an airframe with inert weight inside. Has anybody seen reports that it actually was live? This would explain the Fox report that it suffered a “failure” and only flew 180 miles.)

Using liquid propellant engines to provide TVC for the Sejil does nothing for Iran’s development of solid-propellant missiles and is far from a major advance in their technology. It could be argued, however, that the Sejil does advance the liquid propellant technologies Iran has been trying to perfect with the August launch of the Safir with its cluster of twin gimbaled engines. Of course it’s possible, since I’m still working out the numbers, that adding a solid propellant boosting motor has substantially increased the payload capacity of this missile. In any case, Iran has continued its unique missile development path. Some of their innovations have been brilliant but I cannot help thinking that this one is pretty much a dead end.

There are still problems with my interpretation, namely, what I refer to as cowlings seem to hang down farther than I would expect steering engines to hang. That argues in favor of jet vanes. On the other hand, what is that pipe coming out of the middle of what is supposed to be a solid-propellant casing? Because of this, and other details, I believe that this is the correct interpretation, but I await your comments!

Tomorrow, I’m going to start a five part series of posts about Iran’s liquid propellant missile development program. The first installment will be a speculative piece asking about what evidence exists that Iran is trying to develop higher energy propellants than SCUD-type mixtures of kerosene and nitric acid. Until then, I look forward to your comments.

Comment [39]

I love my job.

You probably noticed that the Iranians tested what Defense Minister Mostafa Mohammad Najjar reportedly claimed is a two-stage, solid-fueled missile with a 1,200 mi range the other day. (Naijar gives an interview in the video, but it is in Farsi — little help? Open Source Center?)

I don’t really see the difference between this missile, Sejjil, and the Ashoura (or Ashura) that Iran claims to have tested earlier in the year — the ranges are similar and externally it looks identical to “Ashura” drawings released by MDA. (Update: Skepticism abounds.)

Josh Pollack raised some very interesting questions about Iran’s solid-fueled programs in a post on the blog, Iran’s Ashura Missile Mystery.

I don’t have any flip answers at this point — though I think it is an excellent argument for why Aegis is a more appropriate missile defense option for Europe than ground-based midcourse.

Either way, I love missile pics as much as the next guy. Wonkporn.

As usual, Fars has the best images. The images at IRNA, ISNA and Mehr seem pretty much the same. The photos may have been distributed to the news agencies.

As usual, some of the galleries don’t include call the pictures. Obsessive types at the Mehr site will want to check out images 404961 though 404968 for those two extra images.

Comment [32]

A diligent reader spotted an article in Haaretz reporting that, in private, Sarkozy has been very critical of Obama’s Iran policy, calling it (or perhaps him) “utterly immature”.

French President Nicolas Sarkozy is very critical of U.S. presidential candidate Barack Obama’s positions on Iran, according to reports that have reached Israel’s government.

Sarkozy has made his criticisms only in closed forums in France. But according to a senior Israeli government source, the reports reaching Israel indicate that Sarkozy views the Democratic candidate’s stance on Iran as “utterly immature” and comprised of “formulations empty of all content.”

Obama visited Paris in July, and the Iranian issue was at the heart of his meeting with Sarkozy. At a joint press conference afterward, Obama urged Iran to accept the West’s proposal on its nuclear program, saying that Iran was creating a serious situation that endangered both Israel and the West. According to the reports reaching Israel, Sarkozy told Obama at that meeting that if the new American president elected in November changed his country’s policy toward Iran, that would be “very problematic.”

It’s a bit of a change from two years ago when Jacques and Dubya were at loggerheads over the same issue but from the opposite sides. I also suspect there are some in Whitehall who share Sarko’s concerns. If Obama does win, bringing the E2 around might not be so easy as many assume.

PS On checking up when Sarko assumed office, I learn from Wikipedia that he is also French Co-Prince of Andorra. Who knew?

UPDATE: As some of you noted in the comments, France has now issued a strong denial.

Comment [12]

Elaine Sciolino in the New York Times cites “European and American officials” as stating the IAEA has in its possession an Iranian document that describes assistance by a Russian scientist in developing a detonation system for a nuclear weapon design:

It was described as a “five-page document in English” dealing with experimentation with a complex initiation system to detonate a substantial amount of high explosives and to monitor the detonation with probes. There was no indication that the document was a translation of a much longer and more comprehensive document in Farsi.

The original document is described by officials familiar with it as a detailed narrative of experiments aimed at creating a perfectly-timed implosion of nuclear material.

According to experts, the two most difficult challenges in developing nuclear weapons is creating the bomb fuel and figuring out how to compress and detonate it.

An agency report last month revealed that Iran may have received “foreign expertise” in its detonator experiments.

[snip]

European and American officials now say that the “foreign expertise” was a reference to the Russian scientist, but offered only scant details. They said the scientist is believed to have helped guide Iranians in the experiments, but that he was not the author of the document.

Am I the only person who thought this sounds awfully similar to Operation Merlin — the alleged covert action to supply Iran with a Russian firing set? Here is the description of Operation Merlin, from James Risen in State of War (via an excerpt in The Grauniad):

The story dates back to the Clinton administration and February 2000, when one frightened Russian scientist walked Vienna’s winter streets. The Russian had good reason to be afraid. He was walking around Vienna with blueprints for a nuclear bomb.

To be precise, he was carrying technical designs for a TBA 480 high-voltage block, otherwise known as a “firing set”, for a Russian-designed nuclear weapon. He held in his hands the knowledge needed to create a perfect implosion that could trigger a nuclear chain reaction inside a small spherical core. It was one of the greatest engineering secrets in the world, providing the solution to one of a handful of problems that separated nuclear powers such as the United States and Russia from rogue countries such as Iran that were desperate to join the nuclear club but had so far fallen short.

The Russian, who had defected to the US years earlier, still couldn’t believe the orders he had received from CIA headquarters. The CIA had given him the nuclear blueprints and then sent him to Vienna to sell them – or simply give them – to the Iranian representatives to the International Atomic Energy Agency (IAEA).

I am not saying that there can’t be two Russians who provided this assistance or that we know Risen’s sources were telling the truth. But I am saying that the two cases are close enough for the leakers to offer a clarification.

Risen claims the Russian in Operation Merlin told the Iranians that there “was a flaw somewhere in the nuclear blueprints, and he could help them find it.” So, maybe he followed up on the offer of help. Or the Iranians called one of his colleagues back home. Or it is a totally independent Russian route to a firing set.

Comment [9]

Speaking of Vienna, the IAEA DG report on Iran is on the ISIS website (Implementation of the NPT Safeguards Agreement and relevant provisions of Security Council resolutions 1737 (2006), 1747 (2007) and 1803 (2008) in the Islamic Republic of Iran, GOV/2008/38, 15 September 2008).

The bottom line is that Iran has 2,952 centrifuges in one module and 820-984 in a second. Overall, the Iranians seem to be moving right along. David Albright and Jackie Shire estimate the Iranians are operating the centrifuges about 85 percent of the time — which is consistent with what I see:

Operating Period	Number	UF6 Fed (in KG)		Efficiency
2007-2008	of Cascades	Actual	Expected	(Actual/Expected)
12 December-06 May (146 days)	18-20	2,300	4,415-4,906	0.47-0.52
06 May-30 August (116 days)	18-23	3,630	3,508-4,482	0.81-1.03

Author estimates derived from IAEA Reports.

Note that, with 103 percent of the minimum, we can’t exclude continuous operation of the A26 module over the most recent period.

Iran is also feeding hex into the IR-1, -2 and -3 centrifuges at the PFEP. (I still think we have the best open source discussion of the IR-3 right here on the blog.)

About that Hex (UF₆)

A couple of days ago Con Coughlin and Tim Butcher published an article in the Daily Telegraph that stated Iran had diverted some Hex from the conversion facility as Isfahan:

Nuclear experts responsible for monitoring Iran’s nuclear programme have discovered that enough enriched uranium, which if processed to weapons grade level could be used to make up to six atom bombs, has disappeared from the main production facility at Isfahan.

The article smelled fishy to me, and not just because I think that wrapping fish and chips is the only appropriate use for the Telegraph.

The story seemed patently false, but now we have a statement from the IAEA’s Melissa Fleming. The statement is available from an Iranian website, but I confirmed the authenticity of the statement with a colleague:

“The article, entitled ‘Iran renews nuclear weapons development’ published in [Friday’s] Daily Telegraph by Con Coughlin and Tim Butcher is fictitious,” IAEA Spokeswoman Melissa Fleming said in a statement.

“IAEA inspectors have no indication that any nuclear material is missing from the plant,” reads the statement….

For emphasis, the DG’s Report also makes clear that all UF₆ is under safeguards:

This brings the total amount of uranium in the form of UF6 produced at UCF since March 2004 to 342 tonnes, all of which remains under Agency containment and surveillance.

[Emphasis mine]

Even terrible reporting, however, can be a teachable moment. And I have been waiting for a good opportunity to share “The gas centrifuge and nuclear weapons proliferation” by Houston G. Wood, Alexander Glaser, and R. Scott Kemp. Wood et al argue in Physics Today that UF₆ production is the easiest step to safeguard in the enrichment process:

Safeguards might also address the covert-facility problem by safeguarding flows of unenriched UF6, starting at the facilities where the UF6 is produced. Traditionally, that material has received relatively little attention. Monitoring unenriched UF6 more carefully can make its diversion to a covert plant more difficult. Thus, although direct detection of covert plants may not be possible, safeguards can make it more difficult to operate those plants with undeclared feed.

I learned a lot in that article; I hope you do too.

Comment [11]

Conversations about a recent news report in the Dutch paper De Telegraaf — that Netherlands has recalled a spy/saboteur from Iran’s nuclear program in fear of an impending attack — are filling my inbox.

Here is the crucial bit of the story:

AMSTERDAM – De Nederlandse inlichtingendienst AIVD heeft de afgelopen jaren een ultrageheime operatie laten uitvoeren in Iran met als doel infiltratie en sabotage van de wapenindustrie in de islamitische republiek.

[znippe]

Een van de betrokken agenten, die onder supervisie van de AIVD wist te infiltreren in de Iraanse industrie, is recent teruggeroepen omdat in de VS de beslissing zou zijn genomen binnen enkele weken met onbemande vliegtuigen Iran aan te vallen. Tot de potentiële doelwitten behoren naar verluidt niet alleen nucleaire fabrieken, maar ook militaire installaties die mede door toedoen van de AIVD in kaart zijn gebracht. Informatie uit de AIVD-operatie is de afgelopen jaren gedeeld met de Amerikaanse inlichtingendienst CIA, aldus bronnen.

Ook konden diverse leveranties worden gesaboteerd en tegengehouden. Het ging om onderdelen voor raketten en lanceerinstallaties.

The basic details are that a Dutch agent infiltrated the Iranian “industry” — apparently in the missile and space launch sector. The activities of this individual extend from sabotage to reconnaissance. The Dutch believe that a decision will be made in the next few weeks about an airstrike (with UAVs?). Fearing that an airstrike using intelligence obtained from this individual would compromise his/her safety, the Dutch have recalled the agent.

Fars has a translation.

I don’t think an airstrike is imminent, but the rest of the story seems plausible. Whattya think?

Comment [28]

Warning: long post.

Observing the frequent travels of the IAEA’s Olli Heinonen to Iran of late, Andreas Persbo suggests that the negotiation of new safeguards measures may be underway for the still-incomplete gas-centrifuge enrichment plant at Natanz, currently undergoing low-level operations.

This raises a rather interesting question: just how does the IAEA conduct safeguards at Natanz these days?

Why You Should Care

The question is interesting and pertinent, too, because if Iran were to attempt to produce HEU for a nuclear bomb, it would probably happen at Natanz. As David Albright and Jackie Shire have pointed out:

Two basic scenarios capture Iran’s most likely routes to developing highly enriched uranium (HEU) for its first nuclear weapons. The first would be for Iran to build and operate a secret gas-centrifuge plant. The second would be for Tehran to “break out” after producing a stock of low-enriched uranium (LEU) that would then be used to jump-start the production of weapons-grade uranium either at its enrichment plant at Natanz or in a secret site.

Drawing on my own knowledge base, admittedly slender by local standards, I’ll go out on a limb to make a further observation on this point. While Iran stays within the NPT, a breakout attempt is not very likely to occur at an unknown site operating in parallel to Natanz.

(Here is where the apprentice lion tamer, AKA guest blogger, apprehensively pokes his head into the maw of the King of Beasts, AKA commenters with serious domain knowledge.)

Simultaneously producing LEU at Natanz and HEU at a secret centrifuge site would be a fraught undertaking. In part because of the telltale UF6 particles that settle on every surface of a working centrifuge plant — including the clothes and skin of personnel — the two programs would have to maintain a rigorous separation to avoid detection.

It would not simply be a matter of delivering every third or fourth new centrifuge to a secret warehouse on the outskirts of (let’s say) Esfahan: there would have to be a duplicate everything and everyone, with no communication between the two sides.

The potential for secret sites is a serious, serious problem, perhaps the most serious problem. But it would become much greater if Iran were to leave the NPT and kick the IAEA out of Natanz.

(No snapping of jaws? Good, let’s continue.)

Back To The Question

Just how the IAEA conducts safeguards at Natanz is not directly publicized, so far as I can tell, but there are some good hints available. A likely starting point, recognizing that it is somewhat dated, is a paper delivered by D.W. Swindle to the March 1990 meeting of the American Physical Society, titled, aptly enough, “Realities of Verifying the Absence of Highly Enriched Uranium (HEU) in Gas Centrifuge Enrichment Plants.”

The processes described by Swindle, which were developed in the early 1980s, serve two major purposes: to ensure that plant operators can’t make HEU onsite without having it detected, and to ensure that they can’t divert LEU produced there to some other location without having that detected, either. (LEU can be further enriched into HEU.)

LEU diversion is deterred mainly by taking a periodic inventory. The centerpiece of the process for deterring HEU production consists of Limited Frequency Unannounced Access (LFUA) inspections. Between four and 12 times a year, inspectors show up and give two hours’ notice for an inspection, within 24 hours of entering the country. Things they do:

• Visual Observation. Inspectors enter the cascade hall and have a look around, to ensure that the piping hasn’t been re-routed.

• Non-Destructive Assay (NDA). Inspectors use portable gamma-ray detectors to measure enrichment levels inside the cascade header pipes. Is it LEU? Is it HEU? This is one way to know.

• Sampling. This is another way to know, more accurate than NDA. It’s not a routine thing, but if NDA detects an “anomaly,” well then.

• Tamper-Resistant Seals. Inspectors place seals in strategic locations and check on previously placed seals, to ascertain whether there has been any fiddling in the meantime.

More current information can be gleaned from a 2004 paper by five members of the IAEA Safeguards Department, titled “IAEA Experience with Environmental Sampling at Gas Centrifuge Enrichment Plants in the European Union.”

The authors describe LFUA in terms of visual observation, “application of surveillance systems,” and NDA. (“Surveillance systems” presumably means cameras, like the one in the picture at the top of this post.) Then the authors describe a new technique introduced in the mid-1990s, environmental sampling (ES):

Environmental samples at enrichment plants are collected by swiping selected areas of the plant with squares of cotton cloth (10×10cm) from sampling kits prepared in ultra clean conditions. The squares of cotton cloth sealed in plastic bags are sent for analysis to the Safeguards Analytical Laboratory (SAL) and/or the Network Analytical Laboratories (NWAL). The analysis includes the measurement of uranium isotopic composition in uranium-containing particles by Thermal Ionisation Mass Spectrometry (TIMS) or Secondary Ion Mass Spectrometry (SIMS).

[I was remiss in not pointing out James’s explanation of a more up-to-date technique, FT-TIMS, in another context.]

Anyone who has bothered to read this far probably already knows that ES has played the starring role in the Iran-IAEA drama. The accuracy of the technique, combined with the persistence of trace amounts of uranium, certainly came as a shock to the Iranians.

Beyond ES, and in some ways even better, there is also continuous monitoring with radiation detectors hooked up to pipes. Basically, this amounts to 24×7 NDA. But the Iranians appear to have managed to resist this measure so far.

Having Established All That

We’re now in a position to interpret the previous IAEA Director-General’s reports on nuclear safeguards and compliance in Iran. The latest such report is dated May 26. It reads, in part:

4. Between 28 January and 16 May 2008, Iran fed a total of approximately 19 kg of UF6 into the 20-machine IR-1 cascade, the single IR-2 centrifuges, the 10-machine IR-2 cascade and the single IR-3 centrifuges at PFEP. All nuclear material at PFEP, as well as the cascade area, remains under Agency containment and surveillance.

5. The results of the environmental samples taken at FEP and PFEP indicate that the plants have been operated as declared. The samples showed low enriched uranium (with up to 4.0% U-235), natural uranium and depleted uranium (down to 0.4% U-235) particles. Iran declared enrichment levels in FEP of up to 4.7% U-235. Since March 2007, fourteen unannounced inspections have been conducted.

So from March 2007 to May 2008, 14 LFUAs took place — an average of one per month, the maximum based on past IAEA practice elsewhere. ES has confirmed Iran’s claims that only LEU has been produced so far. (Natural uranium is what’s fed into the enrichment process, and depleted uranium is what’s left over from it.)

There’s been a fair amount of pushing and shoving between Iran and the IAEA about safeguards measures. (Recall the earlier fight over entry visas for inspectors.) But the story boils down to this: If Iran wants to use Natanz to break out undetected, they’ll have to keep the inspectors out.

Scott Kemp and Alexander Glaser have argued that with enough LEU on hand, and with the right kind and numbers of centrifuges, under the right conditions, it would be feasible (in the absence of continuous monitoring) to do an undetected breakout at a centrifuge plant in the space of a couple of weeks. And who am I to argue with them? But at a minimum, they’d have to fool the cameras, and would be gambling with randomly timed LFUAs.

So What?

You knew there was a point to this, right?

It’s commonly assumed that once the Iranians accumulate a certain number of centrifuges, voilà, they will have crossed the nuclear threshold. This idea is sometimes called “the point of no return.”

That’s why it’s also widely believed that anyone who wants to stop Iran from getting nuclear weapons must deliver high explosives on Natanz at some point soon.

If you’ve followed all of the above, you’ll probably see already why that conclusion does not follow (setting aside what for essentially the same reasons that Albright, Brannan, and Shire have argued about the (in)feasibility of such a plan). But just in case it’s not apparent, here’s why:

• Natanz is under the microscope of the IAEA. Sufficiently quick undetected cheating at this facility is not a realistic proposition in the near-to-medium-term future.

• If someone did bomb Natanz, the Iranians could simply pull out of the NPT and rebuild the plant somewhere else in secret.

• Bombing Natanz could therefore lead Iran to get the bomb sooner than would otherwise be the case.

• On the other hand, if the Iranians were to attempt to break out at Natanz, there would be little to stop the U.S. from bombing the place, since that would at least slow things down somewhat.

Bottom line: using force to prevent Iran from going nuclear would be a much bigger undertaking than just an air campaign. Regime change really would be necessary. But the Iranians could instead be deterred from attempting breakout.

Still, if the Iranians don’t want to tempt fate, agreeing to continuous monitoring would help.

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