The CIA's Aluminum Tubes' Assessment: Is the Nuclear Case Going Down the Tubes?

By David Albright

The Institute for Science and International Security

March 10, 2003, Rev. 1

The Bush administration has tried to make the case that Iraq has a nuclear weapons program that is close to fruition, and Iraq poses an imminent nuclear threat. Because people generally fear nuclear weapons far more than other weapons of mass destruction, proving that Iraq is close to producing nuclear weapons can be a powerful inducement to support war. Critical to the administration's case about Iraqi nuclear weapons has been attempted Iraqi procurements of high-strength aluminum tubes.

The CIA has concluded that these tubes were specifically manufactured for use in gas centrifuges to enrich uranium. Many in the expert community both inside and outside government, however, do not agree with this conclusion. The vast majority of gas centrifuge experts in this country and abroad who are knowledgeable about this case reject the CIA's case and do not believe that the tubes are specifically designed for gas centrifuges. In addition, International Atomic Energy Agency (IAEA) inspectors have consistently expressed skepticism that the tubes are for centrifuges. In his February 7, 2003 report to the UN Security Council, Mohamed ElBaradei, the IAEA's Director General, said: "Based on available evidence, the IAEA team has concluded that Iraq's efforts to import these aluminum tubes were not likely to have been related to the manufacture of centrifuges."

All experts agree that after modification the tubes could be used as a rotor of a poor quality gas centrifuge. Complicating the realization of this design is that the wall of the tubes is unusually thick, and the tubes' diameter is not optimal for such a centrifuge. Many centrifuge experts believe that this design would not work as the basis of a centrifuge plant.

On the other hand, the tubes' dimensions are consistent with a known Iraqi rocket program. ElBaradei moreover reported to the Security Council that extensive field investigation and document analysis failed to uncover any evidence that Iraq intended to use these aluminum tubes for any project other than in rockets.

After months of investigation, the administration has failed to prove its claim that the tubes are intended for use in an Iraqi gas centrifuge program. Despite being presented with evidence countering this claim, the administration persists in making misleading comments about the significance of the tubes.

So Far, No Evidence of a Nuclear Weapons Program

The administration's case has been further weakened because the UN Security Council inspectors have so far found no evidence of an Iraqi nuclear weapons program. This result comes after extensive IAEA assessments of information from UN member states and many investigations in Iraq.

In addition, former members of the Iraqi nuclear weapons program who have escaped Iraq disagree among themselves about the existence of a nuclear weapons program. Some posit that Iraq's nuclear weapons program continues; some say the program ended after 1991. None of these Iraqis have any direct knowledge of any current banned nuclear programs. They appear to all carry political baggage and biases about going to war or overthrowing Saddam Hussein, and these biases seem to drive their judgments about nuclear issues, rendering their statements about current Iraqi nuclear activities suspect.

The Bush administration has tried to use recent Iraqi attempts to obtain uranium from Niger as evidence of a secret nuclear weapons program, but this information has been widely discounted. One person who heard a classified briefing on Iraq in late 2002 said that there was laughter in the room when the uranium evidence was presented. One of ElBaradei's most dramatic findings, revealed on March 7, was that the documents which form the basis for the reports of recent uranium transactions between Niger and Iraq are not authentic.

Iraq's attempts to acquire a magnet production plant are likewise ambiguous. Secretary of State Colin Powell stated to the UN Security Council on February 5, 2003 that this plant would produce magnets with a mass of 20 to 30 grams. He added: "That's the same weight as the magnets used in Iraq's gas centrifuge program before the Gulf War." One US official said that because the pieces are so small, many end uses are possible, making it impossible to link the attempted acquisition to an Iraqi centrifuge program.

Clinging to the Aluminum Tubes

With such weak evidence, the administration clings to the aluminum tubes. The tubes were featured in President George W. Bush's State of the Union address in late January and Secretary Colin Powell's Security Council address in early February.

Yet, the administration has offered few public details about its case or the tubes. It typically restates its views, never answering any technical criticisms of its claims. But publics and other governments need to know the truth, in particular the technical evidence underpinning the administration's conclusion. A critical question is whether the Bush Administration has deliberately misled the public and other governments in playing a "nuclear card" that it knew would strengthen public support for war.

For over a year and a half, an analyst at the CIA has been pushing the aluminum tube story, despite consistent disagreement by a wide range of experts in the United States and abroad. His opinion, however, obtained traction in the summer of 2002 with senior members of the Bush Administration, including the President.

The administration was forced to admit publicly that dissenters exist, particularly at the Department of Energy (DOE) and its national laboratories. This dissent is significant because the DOE has virtually the only expertise on gas centrifuges and nuclear weapons programs in the United States government.

However, administration officials try to minimize the number and significance of the dissenters or unfairly attack them. For example, when Secretary Powell mentioned the dissent in his Security Council speech, he said: "Other experts, and the Iraqis themselves, argue that they are really to produce the rocket bodies for a conventional weapon, a multiple rocket launcher." Not surprisingly, an effort by those at the Energy Department to change Powell's comments before his appearance was rebuffed by the administration.

The disagreement boils down to whether the tubes are specifically for centrifuges or are more likely for use in rockets. The original CIA analysis from over a year ago posited that the tubes could be used only for centrifuges and appeared not to realize that the tubes could also be used for rockets.

The Case Against the Administration's Claim

Determining the truth against this background is difficult. I first learned of this case a year and a half ago when I was asked for information about past Iraqi procurements. My reaction at the time was that the disagreement reflected the typical in-fighting between US experts that often afflicts the intelligence community. I was frankly surprised when the administration latched onto one side of this debate in September 2002. My surprise became concern when I was told that this dispute had not been mediated by a competent, impartial technical committee, as it should have been according to accepted practice. I became dismayed when a knowledgeable government scientist told me that the administration could say anything it wanted about the tubes while government scientists who disagreed were expected to remain quiet.

As a result, I sought to gather a wide range of additional information about the tubes and conducted a range of interviews with government officials, centrifuge experts, and rocket manufacturing specialists. A comparison of this information to the administration's data is not complete, because the administration has refused to release technical details of its investigation.

Based on available information, the most important characteristics of the tubes are assembled in a table, which compares two old, aluminum-rotor centrifuges with a conventional rocket Iraq possesses. The first centrifuge is an early Zippe-type centrifuge from the 1950s and 1960s, although Iraq never built such a centrifuge using an aluminum rotor. Iraq copied 1970s-era Zippe-type centrifuge designs in the late 1980s, focusing first on rotors made from the more advanced material maraging steel, and later on carbon fiber, an even more advanced material. These materials are used instead of aluminum because they result in centrifuges that have over four times the ability to enrich uranium than similar centrifuges made with aluminum rotors. The other centrifuge in the table is the antiquated US Beams centrifuge from the 1940s or 1950s that Iraq pursued in the late 1980s, but abandoned early in its centrifuge effort in favor of more advanced centrifuge designs.

Some of the characteristics of the tubes are compatible with a centrifuge use, but all of the characteristics fit a use in a rocket that Iraq was producing indigenously. This rocket was based on reverse-engineering a helicopter-launched rocket, large quantities of which Iraq had imported from Italy in the 1980s during the Iran/Iraq war and converted into surface-to-surface rockets. The tubes' length, wall thickness, and diameter in particular are consistent with a use in this rocket. Although these tubes could be used as a centrifuge rotor if they were cut, the resulting tube would result in a poor quality centrifuge. Its relatively small diameter and thick walls could create new and potentially significant problems that the Iraqis would need to overcome. An IAEA team of centrifuge experts, quoted by ElBaradei in his report to the Security Council, went further, concluding that "it was highly unlikely that Iraq could have achieved the considerable redesign needed to use [the tubes] in a revived centrifuge" program. In addition, no one has ever built large numbers of Beams' centrifuges or produced significant amounts of enriched uranium in a cascade of such machines. An inevitable conclusion is that the CIA analysis tried to design a centrifuge around the tubes rather than determine the use of the tubes from their characteristics.

The centrifuge design being posited by the CIA has a capacity to enrich uranium that is far below the level Iraq has already demonstrated with different centrifuges. As a result, Iraq would need to build thousands more centrifuges than if it used one of its proven designs. This approach would cause significant delays in building a centrifuge plant and require the procurement of a huge number of other items. Given the number of procurements and the time to test a new centrifuge design and build a plant, Iraq would have to assume its program would be discovered before it was able to produce significant quantities of highly enriched uranium. Given Iraq's need for both speed and secrecy, its choice of such a strategy would be odd to say the least.

Powell's Case

In his address to the Security Council on February 5, 2003, Powell stated that in investigating different batches of tubes that Iraq ordered, there was a "progression to higher and higher levels of specification, including in the latest batch an anodized coating on extremely smooth inner and outer surfaces."

An anodized layer is a thin protective coating placed on aluminum that makes the aluminum more resistant to corrosion. However, bare aluminum without any coating is resistant to corrosion by uranium hexafluoride, the process gas in a centrifuge. There are no industrial centrifuges in the world that use anodized rotors. A well known unclassified fact is that anodization is not necessary for a centrifuge. However, anodization is a common practice in military and commercial equipment to protect against weather and the environment. For example, bicycle handlebars are anodized.

The tubes Iraq acquired in the 1980s for use in its program to indigenously produce a reverse-engineered Italian rocket were not anodized. Most of these tubes did corrode during years of storage. When Iraq started to look for a new supply of tubes in 2000, it decided to order anodized tubes to account for uncertain storage conditions. As a result, anodized aluminum tubes are consistent with a rocket use and not a centrifuge purpose.

Powell's statement on improving specifications and tolerances is also not compelling.1 The Italian rocket and the reverse-engineered Iraqi rocket have different specifications and tolerances. However, the specifications and tolerances of the two rocket designs are consistent with each other, according to a US expert.

A German rocket expert interviewed for this effort who had extensive experience with Iraqi conventional armaments, centrifuge, and missile programs in the 1980s said that these types of rockets often have precise specifications and tolerances. He added that there are even US systems with similar specifications and tolerances, contrary to administration claims. In addition, experts said that the higher levels of specifications mentioned by Powell were likely the result of earlier specifications and tolerances not being sufficient to make the reverse-engineered rockets. The conclusion of these experts is that the more exacting tolerances of the tubes ordered by Iraq are not far in excess of tolerances used in rockets.

This conclusion was echoed in ElBaradei's report which traced the history of Iraq's attempts to build rockets from aluminum tubes from prior to 1987 until today. "Initial attempts to reverse engineer the rockets met with little success," he said. According to ElBaradei, the tolerances were adjusted during later years as part of an effort to revitalize the program and improve the rocket's operational efficiency. In addition, the program languished for long periods and was studied by several Iraqi committees, each of which changed the specifications and tolerances of the tubes, he said.

In addition, past Iraqi behavior on setting tolerances of parts undermines confidence in drawing conclusions about these tubes. In many cases, Iraqi scientists and technicians had difficulty determining adequate tolerances of components. As a result, they would over-specify the tolerances of components.

Thus, dimensions of an object are a much better indicator of an end use than the object's tolerances. For example, the tolerance of a soda can is relatively precise, but that fact does not indicate the end use of the can.

Other Arguments

The administration has leaked several other arguments for its case to the media. These arguments and rebuttals include:

  • The CIA said that the procurements were highly secret, despite Iraq being able to buy the tubes on the open market. In fact, Iraq could not buy the tubes on the open market. Iraq has been forbidden to possess high-strength aluminum regardless of its use unless such an order was approved by the United Nations and subject to monitoring, an impossibility after the inspectors left Iraq in 1998. But these orders were not that secret, according to a US expert. The Iraqi trading company charged with ordering the tubes often sent facsimiles from its Baghdad office to many foreign companies, including the exact dimensions and tolerances in its request. Facsimiles are easy for intelligence agencies to intercept. This method is very different from Iraq's well documented highly clandestine procurement techniques. Click here for more information about Iraqi procurement.
  • The CIA said the Iraqis were planning to pay a "super price" for the tubes. In fact, the Iraqis were not planning on paying an exorbitant price for these tubes. One expert said that Iraq was expecting to pay prices in line with those it was paying for other illicit procurements. In particular, Iraq planned to pay prices consistent with those it paid during the Iran/Iraq war for similar tubes. In addition, increasing the tubes' tolerances did not add lead to a "super price," according to one expert.
  • The CIA said senior Iraqi officials were involved, signifying a nuclear end-use of the tubes. In fact, according to a US expert, the head of the monitoring organization for biological, chemical, nuclear, and missiles was involved in these purchases. But his involvement or that of other officials does not prove a nuclear end-use for the tubes.
  • Conclusion

    Perhaps we will eventually learn that Iraq actually planned to hide a centrifuge purchase in a rocket procurement program. Such cleverness is well within Iraqi capabilities, although Iraq rarely chooses to build a poor product when it can build the same item significantly better in less time. Such a revelation, however, will not vindicate the CIA analysis, which is viewed as atrocious and deceptive by many experts on centrifuges and Iraqi rockets.

    The CIA analysis has wasted the time of inspectors in Iraq while not leading to any progress on exposing Iraq's secret nuclear weapons program. Inspectors have had to spend an inordinate amount of time searching for evidence to prove or disprove the CIA analysis. Faced with overwhelming negative evidence from the inspectors, the proponents of this analysis have simply ignored the negative reports or act as if the CIA possesses secret information it cannot share. If the CIA has such secret evidence, it should share it rather than producing faulty technical analysis.

    By ignoring technical evidence and pushing flawed analysis, the proponents of the CIA analysis undermine the credibility of the President, Secretary Powell, and the CIA. The attacks against those who disagree serve to show their defensiveness and a mean spirit.

    This case serves to remind us that decision-makers are not above misusing technical and scientific analysis to bolster their political goals. The problem is that such a strategy denigrates the process of conducting impartial technical analysis and misleads the public.

    1In this case, the specification refers to a dimension of the tube, such as its length or wall thickness. The tolerance refers to how precise that dimension must be achieved during manufacturing. For example, a wall thickness could be given as 3.0 mm + 0.1 mm. This means that the wall thickness must be between 2.9 mm and 3.1 mm everywhere on the tube.
    [back to the text]

    Table Comparing Characteristics of Aluminum (Al) Tubes Iraq Attempted to Procure Illegally

    Characteristics of Al Tubes

    Beams Centrifuge

    Zippe Centrifuge


    Al rotor, designs of 1940s or 1950s

    Al rotor, designs of 1950s and 1960s

    Designs of 1980s and 1990s

    Al Alloy 7075-T6

    Not used, but could be used

    Not used, but could be used

    Used in US and NATO rockets


    Not used

    Not used

    Prevents corrosion if tubes or rockets stored for long periods

    Length 900 mm

    Likely need to be cut

    For subcritical centrifuge, tube must be cut so that length does not exceed 400 mm.

    Length for rockets Iraq said it reverse-engineered.

    Diameter 81 mm


    Possible, but not an optimal diameter. Leakage rate for this diameter can be about 1-7%, a relatively high rate.

    Standard diameter for helicoptor launched rocket of the type Iraq reverse-engineered.

    Wall thickness 3 mm


    Far too thick for these Zippe designs, but possible to use in existing Iraqi design with advanced bearings and other modifications. But the resulting centrifuge would have far less ability to enrich.

    Standard thickness


    In some cases, acceptable

    In some cases, acceptable

    Consistent with tolerances of NATO rockets of the type Iraq reverse-engineered.

    [back to the text]