Cobalt bomb

A variant of a fission bomb where cobalt is used instead of normal fissionable elements like U-235 in the bomb's design. Cobalt when bombarded by neutrons transmute into cobalt-60 which is a strong emitter of gamma radiation.

The half life of cobalt-60 fallout is around 5 years, which makes it an somewhat ideal weapon when compared to traditional nuclear bombs. Its strong radiation will kill most forms of life in the immediate area, but after about 2 decades, it will be safe to populate.

Cheers,
Steve