Aluminum tubes

The Federation of American Scientists explain:

Iraq's purchase of high strength aluminum tubes—claimed to be part of an effort to build uranium gas centrifuges to enrich uranium for nuclear weapons—was presented as one of the strongest pieces of evidence for a revived Iraqi nuclear weapons program and, therefore, one of the strongest arguments for going to war. In fact, we now know that the preponderance of the pre-war intelligence suggested that the tubes were not suitable for centrifuges and were intended for conventional rocket bodies. Why was there so much concern about aluminum tubes? What role did they—or might they—play? And how do you recognize a centrifuge tube when you see it? This article discusses why centrifuges are important and their key requirements and characteristics and why they are central to concerns about nuclear proliferation.