The head of the UN’s nuclear watchdog says US strikes on Iran fell short of causing total damage to its nuclear program and that Tehran could restart enriching uranium “in a matter of months,” contradicting President Donald Trump’s claims the US set Tehran’s ambitions back by decades.

For those concerned about Iran becoming a nuclear-armed state, it’s essential to understand not just what the attacks by the US and Israel did to the country’s capacity to enrich uranium, but also what’s become of its existing inventory of atomic fuel.