Improvised nuclear device

Improvised nuclear devices or (INDs) are theoretical illicit nuclear weapons bought, stolen, or otherwise originating from a nuclear state, or a weapon fabricated by a terrorist group from illegally obtained fissile nuclear weapons material that produces a nuclear explosion. An IND could be bought, or it could be built from the components of a stolen weapon or from scratch using nuclear material (plutonium or highly enriched uranium). A successful detonation would result in catastrophic loss of life, destruction of infrastructure, and nuclear contamination of a very large area.

Types

If a nuclear yield is not achieved, the result would likely resemble a Radiological Dispersal Device in which fissile weapons material was dispensed locally. If nuclear yield is achieved, results would resemble a nuclear explosion. Like nuclear explosions, IND explosions can be evaluated with a plume map.

Design considerations

The INDs when built from scratch would most likely be of gun-type which is fairly easy to design and manufacture (however, requiring highly enriched uranium).

Improvised nuclear devices are likely to cause more nuclear fallout because of incomplete fission - due to overengineering the pit (making it heavier to ensure fission occurs at least in part of it), using the gun-type design or as a result of a fizzle (yield lower than planned due to engineering/manufacturing errors) — and are likely to be exploded at ground level rather than at an altitude, which causes ground materials to be irradiated and drawn up into the mushroom cloud.