Go ahead and provide your examples. Let's talk specifics.Have they allowed inspections into all of their facilities? If not, that's not transparent. They're doing the same thing the Israelis did. And I don't think you're going to say the Israelis don't have a nuclear weapons program. Sure, we have missing gaps in intelligence, but when their behavior resembles the type of behavior from offenders like the Israels as well as the initial secret program South Korea tried, that doesn't suggest a purely peaceful operation. We have known peaceful civilian usage around the world. We know what that looks like. If Iran was actually going about a purely peaceful operation, their behaviors would resemble that of Argentina, not Israel.
Whether or not they are covered in sanctions currently extant is completely irrelevant. Regardless, this is really just irrelevant to the discussion.Refinement has never been totally clarified under the NPT. It's been a sticking point since the agreement. Countries have complained that the US largely arbitrarily made the rules to which they're largely correct. But it still does not change the cost factor.
Iran could have saved billions by simply importing fuel. And that's outside of the sanctions. Remember that the sanctions only were US based. Nothing stopped Russia, French or others from agreeing to fuel arrangements. Iran under US sanctions before the round of banking sanctions would have had no problem getting such fuel agreements.