Sending uranium to Russia is a good thing?

The conventional wisdom is that all this news about Iran possibly sending low-enriched uranium to Russia is a sign of "progress". The irascible Christopher Hitchens, in an article this week in Slate that quotes the Washington Post, sees it differently. Iran has a backward economy with little respect for science, he says, and may simply not have the technology to deal with the "impurities" in its low-enriched uranium. Hence the need for partners like Russia. Hitchens smells weakness in Iran, and suggests that now would be the perfect time for the West to get aggressive.

So, much kudos to David Ignatius of the Washington Post for his column last Friday, in which he restates the findings of a little-known trade publication with the arcane name of Nucleonics Week. To quote directly, the article reports that there might be some reason to think that:
Iran's supply of low-enriched uranium—the potential feed-stock for nuclear bombs—appears to have certain "impurities" that "could cause centrifuges to fail" if the Iranians try to boost it to weapons grade.
Remember that Iran acquired a good deal of its original materiel on the black market, buying through proxies and using other means of deception, before anyone knew what was going on. This in turn means that it would be very much harder to acquire replacement supplies, in the face of continuing invigilation from the United Nations, the International Atomic Energy Agency, and several intelligence services. Logically, then, even a minor disruption or dislocation of one of the existing key Iranian sites could have the effect of retarding the whole tenuous program for quite a while. And in the meanwhile, the internal clock of Iranian society is running against the continuation of outright dictatorship. So who should be scared of whom?