it would first need to be converted back to UF6 gas. The February report noted that Iran has continued to deny the IAEA access to the military site at Parchin. Citing evidence from satellite imagery that "Iran constructed a large explosives containment vessel in which to conduct hydrodynamic experiments". Such installation could be an indicator of nuclear weapons development. The report expresses concern that changes taking place at the Parchin military site might eliminate evidence of past nuclear activities, noting that there had been virtually no activity at that location between February 2005 and the time the IAEA requested access. Those changes include: Reinstatement of some of the chamber building's features, for example wall panels and exhaust piping. Alterations to the roofs of the chamber building and the other large building. Dismantlement and reconstruction of the annex to the other large building. Construction of one small building at the same place where a building of similar size had previously been demolished. Spreading, leveling and compacting of another layer of material over a large area. Installation of a fence that divides the location into two areas. Most of these activities have also been documented by ISIS in satellite imagery reports, dated 29 November 2012, 12 December 2012 and 25 January 2013. Iran said that the IR-40 heavy water-moderated research reactor at Arak was expected begin to operate in the first quarter of 2014. During on-site inspections of the IR-40 design, IAEA inspectors observed that the previously reported installation of cooling and moderator circuit piping was almost complete. The IAEA reported that Iran will use the Tehran Resarch Reactor to test fuel for the IR-40 reactor, which the UN Security Council has demanded that Iran stop building because it could be used to produce plutonium for nuclear weapons. The IAEA report states that "on 26 November 2012, the Agency verified a prototype IR-40 natural uranium fuel assembly before its transfer to TRR for irradiation testing." Since its last visit on 17 August 2011, the Agency has not been provided with further access to the plant so is relying on satellite imagery to monitor the status of the plant. March 2015 report In March 2015, IAEA Director General Amano reported that Iran did not provide sufficient access or information to resolve a dozen issues related to the possible military dimensions of its nuclear program, giving only very limited information on only one of