Uranium-235 makes up less than 1 per cent of natural uranium.

It can be made from natural uranium and is fissile.

The most prevalent is U-238, which accounts for a vast majority of natural uranium.

Fission products at that point, in about 300 years, are less radioactive than natural uranium.

These reactors use natural uranium, rather than the enriched form, which is difficult and costly to make.

One document says Iraq successfully produced nuclear weapons components out of natural uranium.

Syria maintains that the natural uranium found at the site came from Israeli missiles.

In natural uranium, the content of uranium 235 is only 0.71 percent.

The latter accounts for more than 99% of the weight of natural uranium.

With heavy water, reactors can run on natural uranium.