Mark Hibbs has published specifications for Pakistan’s P3 and P4 centrifuges based on “Western government data.”

I haven’t seen this anywhere else, so here it is (with rough data on the P1 and P2 for comparison):

Desig. Derivation Rotor Velocity (m/s) Length SWU
P1 SNOR/CNOR Aluminum 350 1-2 1-3
P2 G2 Maraging Steel 500 1 5
P3 URENCO 4M Maraging Steel 485 2 11.6
P4 SLM/Unknown Maraging Steel 508 3.2 21

Source for P3 and P4: Mark Hibbs, “Pakistan developed more powerful centrifuges,” Nuclear Fuel, January 29, 2007, 1, 15-16.

I find it interesting that Pakistan remained committed to maraging steel, rather than carbon fiber, as the material for its centrifuge rotors. Sources told Hibbs that “procurement breakthroughs” were partially responsible for Pakistan obtaining maraging steel with higher tensile strength necessary for the P4 centrifuge.

I am fascinated by procurement networks. Recently, I wrote an article in The Bulletin entitled, “A Crisis of Confidence,” arguing that the principal challenge facing the nonproliferation regime is not a crisis of compliance, but rather confidence among US policymakers about our ability to detect clandestine gas centrifuge programs.

It is my hypothesis that US policymakers were late to recognize the challenge posed by gas centrifuges, and may be over-reacting (ALUMINUM TUBES! THE END IS NIGH!). Despite the understandable panic, options for controlling sensitive components and monitoring national programs may still be feasible, if difficult.

At the very least, it is way too early to conclude that such efforts are futile and throw in the towel.

That argument, by the way, will form the basis of my presentation on Tuesday, February 20 at the Belfer Center on “Gas Centrifuges and the Future of the Nonproliferation Regime.”