a real nuclear bomb must, in addition to radiation, have other external factors of destruction, such as thermal and explosive effects. but in the current situation, I think it will not be required to prove this.If putin blows up the dam in Ukraine will that be considered a WMD attack worthy of NATO response. Certainly a war crime for mass drownings of civilians with no military purpose.
If putin uses a dirty bomb will we know it or will we assume it was a full on atomic bomb that was a dud? Is there any difference in results?