Parchin is a military site that has been in the news lately because the IAEA is insisting on sending inspectors there, and Iran has been resisting the pressure. While this has naturally led many US media outlets to suggest that Iran is hiding something there, Hassan Beheshtipour explains Iran's position over at IranReview.org
1. No country [would] ever allow the IAEA to inspect its military sites because the agency is missioned to merely visit nuclear sites, and non-nuclear military bases [are not] covered by its inspections [authority].
2. In order to prove its goodwill and reveal [the] falsehood of the Western media propaganda, Iran has already allowed IAEA inspectors to visit the site twice in 2005, and after each visit, the inspectors said nothing illegal had been found there. Olli Heinonen, the deputy to the then director general of the IAEA, Mohamed ElBaradei, had orally promised that if Iran allowed inspection of the military site in Parchin, they would announce once and for all that Parchin is a non-nuclear site and would need no further inspection. However, as the agency’s deputy director general for safeguards changed, the new deputy, Herman Nackaerts, announced in 2011 that Parchin site needs to be inspected again in the light of alleged studies whose information had been provided by some member states of the agency. This issue has caused Iran not to trust the promises given by the IAEA officials anymore.
3. Following three rounds of negotiations with delegates of the IAEA, Iran announced that the agency would be able to revisit Parchin site if two conditions are met. Firstly, they should promise that following the visit, there would be no further request to inspect Parchin again. Secondly, documents related to the agency’s alleged studies should be made available to Iran in order to make it possible for Tehran to evaluate that information and give an appropriate answer. The IAEA, in return, responded to Iran’s logical request by claiming that countries providing information about the alleged studies would not allow copies of those studies to be provided to Iran. As a result, the agency rejected Iran’s request and denied the Islamic Republic of an opportunity to defend itself by alleging that the IAEA, an impartial international organization, is competent enough to verify the studies.
4. The Islamic Republic of Iran expects the IAEA to guarantee that after its inspectors visit the military site at Parchin, there would be no leak of confidential information related to this non-nuclear military site and such information remain secret. This is a result of the background of the IAEA's performance in similar cases. For example, during the agency’s work in Iraq, information related to non-nuclear military sites of that country were made available to other states a few years before military invasion of Iraq by the United States. Of course, the United States announced that it had not gained that information through the IAEA inspectors, but at any rate, the leak of confidential information about Iraq’s military sites dealt a drastic blow to credit of the agency regardless of the source of the leaked information.
The writer goes on the remind readers that the IAEA and Iran resolved most of the "outstanding issues" between them back in 2007-2008, after they had reached a "Modalities Agreement" for a step-by-step process of cooperation, and,
At present, Iran is also ready to cooperate with the agency on all issues provided that the cooperation is mutual and based on a correct understanding of Iran’s security considerations.
I should point out here that regarding point no. 3 raised by Beheshtipour, former IAEA head El-Baradei wrote in his memoirs entitled "Age of Deception" about how ridiculous the thought it was that Iran was expected to rebut evidence that it was not allowed to see. In fact, under the 2007 Modalities Agreement, which led to the resolution of all of the claims against Iran except for the "alleged studies", Iran agreed to provide an evaluation of these claims if it was presented with the documentation first. However the US has prevented the IAEA from sharing the information with Iran, and in some cases the US has even prevented the IAEA itself from seeing the full documentation which forms the basis of these "Alleged Studies" even though there are signficant doubts about the veracity of these same documents. Iran supplied their promised evaluation in the form of a 117-page document anyway. Under the terms of that Modalities Agreement, this was all Iran was obligated to do, and the IAEA was then bound to conclude the issue. That, of course, is not what happened. Read more here