There are folks out there dreaming about a daring raid by special ops forces to grab Iran’s stock of enriched uranium. Trumpies would like to grab the Ayatollahs’ goodies. People concerned about proliferation would like the material under positive control. I would advise against such a raid.

The enriched uranium seems to be at Isfahan (Esfahan on the map), or at least the relative lack of attack on Isfahan seems to indicate that that is where the US military believes it to be, although today Isfahan was hit. The amount of enriched uranium is said to be 400 kilograms or more.

The concern is that Iran will continue to hold this uranium, which can be further enriched to bomb grade or itself can be made into a bomb. Or that others will acquire it in a chaotic war situation.

The uranium is most likely in the form of UF6 gas, which would be stored in heavy metal cylinders. The Iranians have been moving it around, so it’s probably in medium-sized or small cylinders. UF6 is difficult to handle and reacts with water to produce uranyl fluoride and HF gas, which is nasty stuff. But this is a one-off, if a cylinder is opened. After that, no big deal. Contrary to a belief that seems to be circulating on social media, there is no point in making uranium into a dirty bomb. Uranium, enriched or otherwise, is slightly more radioactive than dirt.

Let us consider the worst case: Terrorists acquire all the enriched uranium. They would have to convert the UF6 to uranium metal and then form the metal into the shapes necessary for a bomb. This takes a chemistry laboratory with significant throughput and people who know how to do it. Could nonspecialists do it from Wikipedia? Maybe, although I doubt it.

Iran is highly motivated to keep the uranium safe, but those guarding it could be killed or might have to evacuate under wartime conditions. Those same wartime conditions would also make it difficult for others to access the uranium, which the regime may have stored in a tunnel and then covered the tunnel entrance with soil and stone.

What would a special operation look like?

Let’s start with getting to where the uranium is. If it is at Isfahan, it’s about 500 miles from the coast, maybe 800 to where the US ships are. That’s a long way to go in a helicopter in a war zone. Or would the approach be by land? A long way to drive. Either vehicle is going to need fuel on the way in and out.

The special ops forces would have to get past the guards. And then they will have to move many gas cylinders, probably with superstructures.

At 60% enrichment, nuclear criticality becomes a concern in storing uranium. The UF6 will have to be stored in increments small enough to prevent the UF6 from being configured in such a way as to allow neutron production to take off.

For 400 kilograms of uranium, the total weight of UF6 will be 593 kilograms, which I’ll round up to 600. I’m using approximate numbers to show what would be needed to take the uranium out of storage and out of the country.

I’ll assume that each cylinder contains 10 kg of UF6, plus the weight of the cylinder, so let’s say 15 kg each. Also for criticality safety, there will probably be a structure made of piping around the cylinder to separate the cylinders. The piping structure will fit into a larger structure for easier transport. The special ops team MUST understand that the piping structures must not be removed.

That’s 60 cylinders. If it’s 20 kg per cylinder, that’s still 30 cylinders. A large enough transport vehicle is needed, or more than one vehicle.

And then the vehicle(s) must get out of the country, through the war zone.

Alternatively, the special ops forces could set a large explosion to destroy the cylinders and release the UF6. The UF6 would rapidly react with the water in the atmosphere – there’s always some – and drop soluble uranyl fluoride around the release site. That would contaminate the soil and possibly water in the immediate area. It would prevent future use of the stock by Iranians or others, but it would be fodder for never-ending conspiracy theories.

All this must be done with a war in progress. The raid that killed Osama bin Laden was done under non-war conditions. Project Sapphire, which removed 600 kg of enriched uranium from Kazakhstan, was done under peacetime conditions, with the cooperation of the Kazakhstani government. It took a month. Operation Eagle Claw, the attempt to rescue the American hostages in Iran, failed.

Action movies have a lot to answer for.

Cross-posted to Nuclear Diner