 :It reacts as would be expected by any strong fluoridating agent, I'd think. Several common and weapons-grade radioactive materials are free metals, and it would likely burn those the same way it burns any other free metal. It's worth noting that uranium hexafluoride is a common method of storing uranium, whether prior to or subsequent to enrichment, and ClF3 would have NO reaction to this fully-fluoridated compound; considering the nature of this stuff, something it DOESN'T burn could be considered more interesting than something it does.   