The graph below, obtained by AP from "a country critical of Iran's atomic program to bolster", appears shows that Iran has been trying to create a weapon more powerful than the bomb dropped on Hiroshima.
The graph was eluded to in a report released by the International Atomic Energy Agency last year, but not included. Here's how the AP describes it:
The IAEA report mentioning the diagrams last year did not give details of what they showed. But the diagram seen by the AP shows a bell curve - with variables of time in micro-seconds, and power and energy both in kilotons - the traditional measurement of the energy output, and hence the destructive power of nuclear weapons. The curve peaks at just above 50 kilotons at around 2 microseconds, reflecting the full force of the weapon being modeled.
The bomb that the United States dropped on Hiroshima in Japan during World War II, in comparison, had a force of about 15 kilotons. Modern nuclear weapons have yields hundreds of times higher than that.
One expert the AP spoke to said that the graph appeared to be an attempt to understand the process, rather than a diagram explaining an actual bomb. "The yield is too big," David Albright, of the Institute for Science and International Security, said.
Iran has denied it has plans to develop a nuclear weapon.
Please follow Military & Defense on Twitter and Facebook.