What's a ‘Dirty Bomb’ and Why Is There Concern in Ukraine?

Ukraine has asked international monitors to inspect two nuclear facilities to ensure material hasn’t been diverted to build a so-called dirty bomb. The request followed Russian assertions that Kyiv’s government was laying the groundwork for the detonation of such a device, potentially contaminating land with radiation and causing mass panic. The US and its allies in the North Atlantic Treaty Organization have rejected the Kremlin’s claim.

A dirty bomb is shorthand for what nuclear-security officials call a radiological dispersal device. They usually involve some kind of radioactive waste paired with regular explosives like dynamite, which can spread the contamination upon detonation. They are seen as instruments of terror, built to sow panic and economic damage. It doesn’t contain anywhere near the energy or destructive potential of nuclear weapons, which are fueled with highly enriched uranium and plutonium. Those produce atomic chain reactions that can level cities.