How Do You Day "Mushroom Cloud" in French?

Okay, let me pose a hypothetical for you. Let's say you have a country who was once an ally, but has openly declared themself as a "balance" to the USA. They have opposed policies against terrorists, and against known tyrants like - oh, say - Sadaam Hussein, and run for office on a platform which is little more than Anti-America. Hypothetically, how would you reward such a nation?

Well, apparently in real life, you send them a whopping load of plutonium. The BBC is reporting that the USA is sending a load of weapons-grade plutonium to France on a British freighter. This is apparently the first-time such potential mushroom-cloud-fodder has been transported between nations. All earlier transports on record were of non-weapons-grade stuff, and would at least require a thief to do some processing to become a nuclear power.

I don't get it. I just don't get it.