Iran has not signed the Addional Protocol, so it is in its right not to abide with that. By a similar logic, Israel has not signed the NPT, so they are allowed to have nuclear weapons. You can't have it both ways. If Israel is not bound by treaties it did not sign, neither is Iran.
Palestinian youths throw stones at security forces in Shoafat, E. Jerusalem; none injured (Haaretz)
from the article: Report: New Iran nuclear facility will be operational soon