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
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
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
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
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.