Chris is correct...you can also read to your heart's content all the IAEA reports on Iran's nuclear

program in the linked document.

As for my understanding, I'm not a nuclear physicist, but I have an Engineering Masters Degree with a focus on Energy technologies, especially Nuclear...plus 10 years of work experience in the Nuclear Power field as both an engineer and Program Manager for Fast and Thermal Reactors...i.e. I understand more than most people do about this subject.

Link: https://www.iaea.org/newscenter/focus/iran/iaea-and-iran-iaea-board-reports...