The previous three pathways occur at facilities that Iran has declared. But what if they try to build a nuclear program in secret? That’s why this deal is so important. Under the new nuclear deal, Iran has committed to extraordinary and robust monitoring, verification, and inspection. International inspectors from the International Atomic Energy Agency (IAEA) will not only be continuously monitoring every element of Iran’s declared nuclear program, but they will also be verifying that no fissile material is covertly carted off to a secret location to build a bomb. And if IAEA inspectors become aware of a suspicious location, Iran has agreed to implement the Additional Protocol to their IAEA Safeguards Agreement, which will allow inspectors to access and inspect any site they deem suspicious. Such suspicions can be triggered by holes in the ground that could be uranium mines, intelligence reports, unexplained purchases, or isotope alarms.
Basically, from the minute materials that could be used for a weapon comes out of the ground to the minute it is shipped out of the country, the IAEA will have eyes on it and anywhere Iran could try and take it: