A report published last week by the Washington-based Institute for Science and International Security (ISIS) states that military strikes are unlikely to destroy Iran's centrifuge program for enriching uranium.

The report was co-authored by David Albright, president of ISIS and one of the most important civilian experts in the U.S. on nuclear programs, and senior analysts Paul Brannan and Jacqueline Shire. "Considering the modular, replicable nature of centrifuge plants, we conclude that an attack on Iran's nuclear program is unlikely to significantly degrade Iran's ability to reconstitute its gas centrifuge program," they write.

They say there is no room for likening strikes on Iranian nuclear facilities to the Israeli bombings of the Iraqi nuclear reactor in 1981 and the clandestine Syrian reactor last year: Destroying the uranium enrichment plants at Natanz and the conversion facility in Esfahan - where the raw material for the enrichment plant is produced - could not be accomplished in a single sortie and would require employing much greater force than Israel used against Iraq and Syria.

Beside the need for multiple attacks and major firepower, there is the problem of locating the targets. "Based on interviews with knowledgeable government officials, intelligence agencies simply lack reliable information on the full scope of Iran's centrifuge facilities and activities," the American experts write.

The International Atomic Energy Agency does not know, for example, where Iran makes all the components for the uranium enrichment centrifuges. Unless this production is derailed, the Iranians could reconstitute their project relatively quickly if attacked.

The researchers contend that a military attack would only lead Iran to rebuild its nuclear program and speed up development at clandestine plants. Moreover, if the Iranians think an attack is imminent, they can stash centrifuge components and materials in hidden locations. In any case, they point out, Iran has already stockpiled enough natural uranium gas to produce weapon-grade uranium for 30 nuclear weapons. Complicating matters still further, the gas for the centrifuges is stored in numerous small canisters designed to withstand damage, so aerial attacks would have to hit close to destroy them.

In contrast to Iraq and Syria, which depended on foreign suppliers to rebuild their reactor-based programs, Iran would not need outside help to rebuild its widely-dispersed gas centrifuge uranium enrichment program.

The experts cite the facilities where Iran has manufactured centrifuges for enriching uranium, and report that the Iranians secretly purchased in Britain a large amount of super-strong steel for producing one of the centrifuge's most important components. This special steel is controlled by suppliers, and the researchers believe the Iranians got around British restrictions by purchasing it in the form of rods, rather than the preferable tubes, and later reworking them for use as centrifuge bellows.