Iran informed the IAEA in 2003 that it had stored most of the liquid waste from the "testing of processes envisioned for UCF, isotope production experiments at TRR, and the use of pellets for testing chemical processes for the MIX facility" at a previously undeclared waste storage facility in Isfahan (Esfahan). [1] Tehran submitted design information to the IAEA, granted inspectors access to the site and presented the waste from the experiments. [2]

Sources:
[1] "Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran," International Atomic Energy Agency (IAEA), 26 August 2003, www.iaea.org.
[2] "Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran," International Atomic Energy Agency (IAEA), 6 June 2003, www.iaea.org.