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Preventing Illegal Exports: Learning from Case Studies, Part II*

by David Albright

April 9, 2001

Technical advice remains invaluable to proliferant states. Iraq was fortunate to have recruited three extraordinarily knowledgeable experts to help its gas centrifuge uranium enrichment program in the period 1988-1990. Walter Busse, Bruno Stemmler, and Karl Heinz Schaab had worked for years at MAN New Technology in Munich Germany, an important subcontractor to the German Urenco partner. Iraq recruited these experts through H&H Metalform.

These individuals were all deeply involved in the development of Urenco gas centrifuges. The first viewgraph is a schematic of an early Urenco-type centrifuge.

Stemmler was a physical chemist who started work at MAN in 1969. One of his first major responsibilities was to create and direct MAN's first separation laboratory, which housed about 20 centrifuge test stands. In addition to testing and developing early MAN and Urenco centrifuges, Stemmler was also one of the principal inventors of a process to coat or oxidize maraging steel centrifuge components, enabling the components to better resist corrosion and thus operate longer. Busse, who by 1988 had been retired from MAN for several years, was a leading expert in forming specialty steel tubes and other components of centrifuges. While at MAN, Busse had headed the section charged with manufacturing centrifuges that used maraging steel, an extremely strong and relatively light steel that enables centrifuges to spin faster. Schaab had helped develop the manufacturing processes for making and testing carbon-fiber rotors, which are more advanced than maraging steel rotors.

How much and exactly what type of assistance these three individuals provided Iraq has been intensively studied for over a decade. We will probably never develop an entirely consistent and complete picture of what they provided to Iraq. But it is clear that these experts provided a considerable amount of sensitive information about Urenco gas centrifuges. The assistance was broad in scope, occurred regularly in the period 1988- 1990, and included many advanced Urenco technologies. The level of assistance provided by these three experts was key to progress in the Iraqi gas centrifuge program.

These three provided the Iraqi gas centrifuge program with classified design drawings of centrifuges developed in the late 1960s and early 1970s and a newer, advanced design from the mid-1980s. They also provided documents describing many sensitive subjects, including testing and manufacturing methods, detailed specifications of centrifuge components, cascade operation, and information about the bottom bearing and magnets used in the upper bearing. They provided centrifuge components to Iraq. They made some of these components themselves. Other components are believed to have been taken from MAN.

A consequence of this assistance was that Iraq dramatically accelerated its gas centrifuge program in the late 1980s. Within a few years of starting, Iraq was approaching the stage of being able to manufacture subcritical gas centrifuges based on Urenco designs and assemble them into a small cascade.

Stemmler's August 1988 Visit to Iraq and the Test Stand Facility at Rashdiya

Stemmler first visited Iraq in August 1988 with Busse and Dietrich Hinze, a co- owner of H&H Metalform. Busse had recommended Stemmler to Hinze and the Iraqis, and H&H organized the trip. The second viewgraph is a picture of Stemmler in front of his house, near Munich.

Stemmler brought a stack of sensitive reports and drawings on this trip. This information stood as a significant milestone in the Iraqi centrifuge program, according to the then-head of the Iraqi centrifuge program, known to the Germans by his codename Muhammad. The drawings included two full-size assembly drawings of a subcritical G1- model centrifuge containing one rotor tube, and a supercritical G2-model centrifuge containing two rotor tubes connected by a single-convolution bellows.

The Iraqis spent several days asking Stemmler questions about gas centrifuge operation in a guarded ministry building in downtown Baghdad. In addition to providing information about his background and experience, Stemmler answered a range of questions about centrifuges stimulated by the documents he had brought.

Iraq had started its gas centrifuge program in 1987, and was already operating a gas centrifuge test stand, using a machine that Iraq called the GS-1 (gaseous separator-1). However, this centrifuge was based on an unclassified 1940s or 1950s design by Jessie Beams, who was a well-known and widely published professor at the University of Virginia. Beams is universally recognized as a pioneer in the development of gas centrifuges. However, not surprisingly, Beam's early, unclassified designs were inefficient. With Iraq's weak manufacturing capabilities and generally poor technical skills, the resulting GS-1 was working poorly.

During this visit, the Iraqi centrifuge experts asked Stemmler to help them overcome vacuum problems in their Beams-type gas centrifuge test stands. They took Stemmler to Rashdiya, on the northern outskirts of Baghdad. Rashdiya was the center of Iraq's research and development program in centrifuges.

The third viewgraph is a 2-meter satellite image of Rashdiya as it appeared in late 1991. At the time of Stemmler's visit, only a portion of the buildings was finished. The fourth viewgraph shows the large workshops building from just outside the perimeter.

Once at Rashdiya, Stemmler went to a small building (later called building 22 by Iraq) that had been finished in early 1988 (see fifth viewgraph). Inside, Stemmler found two test stands, one designed to conduct mechanical tests, and the other designed to use process gas in the centrifuge. Each was located in a "pit." Each pit was about 6.5 meters deep, extending 2.5 meters below ground level and about 4 meters above the floor. Forty-centimeter thick concrete walls, to which the test centrifuges were attached, surrounded the above-ground portion of the pit. The Iraqis had calculated that this wall thickness was required in case a heavy centrifuge jacket (60-70 centimeters long) was to break away from its fixtures while spinning at high speed and crash into a wall.

The sixth viewgraph shows the inside of the building as found by Action Team inspectors in 1995 or 1996. Iraq had dismantled the pits, and after the 1991 Persian Gulf War it had placed miscellaneous equipment throughout the building to disguise the building's true purpose.

Stemmler could hear the test stands when he approached them, which confirmed the existence of problems in the vacuum system. He was able to fix the vacuum problem relatively easily.

Although Stemmler's assistance was rather mundane, it allowed the Iraqis to overcome an important "bottleneck" in their program. The Iraqis knew when they started that the Beams-type centrifuge was not the best one to pursue, but they understood that operating this centrifuge would provide valuable experience. According to senior Iraqis, without the experience of the Beams-type centrifuge, the new designs acquired from Stemmler in August 1988 "might have looked strange." Even though these new drawings "provided a clear road" for the development of a more advanced centrifuge, the Beams- centrifuge program continued until the technology was proven. In the end, the Beam- centrifuge program provided important experience about centrifuge operation and manufacturing.

Later, when Stemmler was asked by the media and German authorities for the location of Rashdiya, he placed this test stand building in southeastern Baghdad. He was driven to the site in a circuitous way, and this process disoriented Stemmler. As a result, Rashdiya was not discovered until after the Persian Gulf War.


*Presented at the following conferences: (1) "Non-Proliferation, Nuclear Security and Export Control: Lessons and Challenges," sponsored by ISIS and the Center for Export Control, Moscow, April 19-20, 2001, and (2) "International Seminar on Export Controls and Nuclear Proliferation," sponsored by ISIS and the Export Control Laboratory of the Institute of Physics and Power Engineering, Obninsk, April 23-24, 2001. [Back to the top]

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