Pakistan developed more powerful centrifuges

After developing the so-called P-1 and P-2 centrifuges in the late 1970s and 1980s, Pakistan proceeded to develop far more capable models using improved grades of maraging steel, according to some Western government intelligence data that Platts has obtained.

Maraging steels are carbonless iron-nickel alloys that are age-hardened to martensite, a steel with a highly regular crystal structure, and then tempered at about 500 degrees C. The tempering results in strong precipitation hardening and ultra-high strength.

While individual segments of Pakistan's aluminum P-1 model had a throughput of less than 1 SWU/year, P-2, which features two maraging steel rotor tube segments, had a throughput of about 5 SWU/yr. P-3, the first of two later centrifuges, according to the intelligence information, is a four-tube model with a throughput of just under 12 SWU/yr. A successor model, P-4, may have a throughput slightly over 20 SWU/yr, the information indicates.

Pakistan first built P-1 and P-2 using data misappropriated from the Urenco program before 1976. Some intelligence data suggest that P-3 and P-4 may resemble centrifuges that were on the drawing board or otherwise under development between the mid-1970s and the mid-1980s. However, Abdul Qadeer Khan, the Pakistani metallurgist who the Dutch government believes stole the design information for P-1 and P-2, left Europe at the end of 1975 to put together a uranium enrichment program in Pakistan.

According to sources, it is believed that Khan Research Laboratories, or KRL, in Rawalpindi, began working on the P-3 and P-4 centrifuges in the second half of the 1980s and well into the 1990s. Development of P-2 had been completed well before 1990, Western officials said.

In early 2006, the IAEA began investigating whether Iran, in addition to obtaining design information for P-1 and P-2 centrifuges from Khan, might also have obtained design information or other know-how for more advanced Pakistani centrifuges.

The IAEA Department of Safeguards had at that time explored in depth Iran's access to P-1 centrifuge data. But reports sent by the IAEA secretariat to the agency's governing board document that the IAEA has not succeeded in reconstructing and then verifying the extent to which Iran pursued development of P-2 machines.

Since the IAEA's investigation of Iran's nuclear activities began in 2003, Iranian officials, including senior figures responsible for Iran's enrichment program, have suggested Iran planned to develop centrifuges more advanced than P-2. The IAEA, sources said, last year therefore wanted to know whether Iran had obtained design information for P-3.

According to Western diplomatic sources, Iranian officials have suggested to foreign interlocutors that they are aware Pakistan developed P-3 centrifuges as well as the still more capable P-4.

P-3 is said to be a supercritical centrifuge about two meters tall, based on four rotor tube segments made of maraging steel, each about the same length as the two tube segments featured in the P-2 model. According to Western government data, P-3 has a design throughput of 11.6 SWU/yr, about twice the throughput of P-2. The peripheral velocity of the P-3 rotor assembly is said to be about 485 meters per second.

Resemblance to Urenco's 4-M

According to the data, the P-3 centrifuge may resemble to some extent a Urenco centrifuge called 4-M. That four-segment model was under development by Ultra-Centrifuge Nederland, or UCN, then the Dutch Urenco centrifuge technology partner, from about 1974 through 1980.

A classified Dutch government intelligence report from 1979, which surfaced two years ago, spelled out that, in addition to getting access to the CNOR design which became the basis for P-1, and the G-2 design which was the basis for P-2, Khan had access to data for 4-M. In 1979, when the Dutch government was investigating Khan's employment by a UCN contract firm, the 4-M was the latest UCN centrifuge to go into production, and it was being installed in UCN's newest cascades at Almelo.

In March 2005 Dutch lawmakers queried the government about the possible diversion of 4-M technology outside the Urenco program. The government informed them that "via diplomatic channels it became known that (the IAEA) has no information suggesting that 4-M technology is in Iran or Libya."

But it was less clear, government ministries said, whether Pakistan had obtained the 4-M design. They said that would have been "possible," but added, "it is not known to us whether Pakistan is in possession" of the know-how corresponding to 4-M.

This is an excerpt. To see the full length feature, contact support@platts.com.

Created: January 29, 2007

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