Iran claims it can fuel nuclear reactors

Nuclear chief Gholamreza Aghazadeh said Iran had enriched uranium to 4.8 per cent purity, which surpasses the 3.6 per cent level Tehran declared it had achieved in April. To produce electricity, nuclear reactors require uranium enriched to 5 per cent.

Enrichment is a highly difficult process that takes gas produced from raw uranium and aims to increase its proportion of the uranium-235 isotope, needed for nuclear fission.

The gas is pumped into a centrifuge, which spins, causing a small portion of the heavier, more prevalent uranium-238 isotope to drop away. The gas then proceeds to other centrifuges — thousands of them — where the process is repeated, increasing the proportion of uranium-235.

Enrichment typically starts out with a gas that is 0.7 per cent uranium-235. It must be boosted to around 5 per cent to produce fuel for a reactor — or 90 per cent for the material for a warhead.