Take a look at the article in Jane’s Intelligence Review (subscription only) by Geoff Forden and John Thomsen expanding on a proposal to develop a multinational consortium to operate a five million SWU-kg a year enrichment facility at Natanz.
I wondered about the self-destruct mechanism, the longer article has an explanation.
As I suspected, the self-destruct mechanism is a centrifuge-specific approach:
For instance, the bottom of the T-21’s bearing, which circulates oil between it and its support cup, is extremely complex and difficult to manufacture. It might be possible to arrange so that the bearing would be destroyed if the rotor was stopped to modify the plant to produce highly enriched uranium (the rotors are usually left running permanently because of the difficulty in bringing them back to speed, so this should not be a major problem in normal operation). If this happened, Iran would find it impossible to use the centrifuges without a major development programme lasting many years. It could also be arranged that, instead of simply destroying the bearing, the whole rotor would be destroyed by smashing it into the casing cylinder because of conservation of angular momentum.
Interestingly, one of the most controversial elements of the proposal—to supply advanced Urenco T-21 centrifuges that are 50 times as powerful as Iran’s P1 design—works as a safeguard, since Iran would have rather more difficulty repairing the more technologically complex centrifuges.
The authors of this proposal proceed on the naive assumption that the problem is merely technical in nature, when it seems to be political. There are many ways to resolve the technical problem of the potential risk that a civilian enrichment program can be diverted for military use, and the Iranians themselves offered a few options worthy of greater consideration. The US/EU position is that Iran must not enrich uranium at all, and Iranians must not even acquire the technical know-how (not even by participating in enrichment programs in 3rd countries like Russia.) This is quite clearly unsellable by the Iranians to their street, and the US/EU know it. This leads to the suspicion that the nuclear issue is not the real bone of contention, but merely masks a political/ideological goal. In that case, what’s the point of these proposals to resolve the technical problems of non-proliferation? They have been dismissed off-hand for a reason.
Interesting proposal. I’m not sure that it’s actually necessary to “build in” self-destructive mechanisms, since these are, after all, “self-disassembling” machines already. Talking too much about self-destruction would make this option a no-go for Iran. This would end up trading off a short-term proliferation threat for a longer-term one (if, say, Iran nationalized the facility and set about trying to reverse-engineer the right bits or re-assemble the cascade).
Of course, they could use the output of this cascade as an input to a much smaller, clandestine one as well.
Still, worth thinking about, and it sets some nice precedents.