Nuclear security

How to build and deliver a nuclear weapon

The key ingredient in a nuclear bomb is enriched uranium — or plutonium, which can be obtained through the combustion of uranium.

Uranium is a relatively common mineral, found both in the ground and under the sea.

Some 20 countries operate uranium mines. According to the World Nuclear Association, more than two-thirds of uranium production comes from three countries — Kazakhstan (39 percent), Canada (22 percent) and Australia (10 percent).

Natural uranium is composed of uranium-238, which makes up 99.3 percent, and uranium-235, the remaining 0.7 percent. Only uranium-235, called "fissile uranium," can be used for nuclear fuel.

Enrichment refers to the process of increasing the proportion of U-235 in order to obtain enough fuel to make a nuclear bomb.

In one process, uranium ore is crushed and ground before being irrigated, or leached, with sulphuric acid. In another, groundwater and oxygen are injected into the rock to extract the uranium.