The MTR was a French design of a type named Osiris. The French named the Iraqi reactor from Osiris + Iraq to give Osiraq (Fr. Osirak), the Iraqis named the reactor Tammuz 1. As well as the reactor, construction and technical assistance, the French sold around 12.5 kg of 93% enriched uranium 235 fuel (HEU) to the Iraqi government.
Many believed the reactor was part of the Iraqi nuclear weapons program. The Iraqi government had tried and failed in 1974 to buy a French gas-graphite plutonium producing reactor and a reprocessing plant and they had also failed in an attempt to buy an Italian Cirene reactor. France agreed to sell them the MTR and its associated laboratory equipment.
The Israeli government was deeply concerned at this purchase. Despite Iraqi claims that the plant was for peaceful use it was an unusual choice. An MTR design is useful for countries with established nuclear reactor construction programs but less so otherwise. The reactor used HEU fuel as standard. The substantial Iraqi purchases of uranium ore could be treated at the plant to produce plutonium, the Iraq government had also purchased a fuel fabrication plant and a recovery 'hot cell'.
However the plant was under IAEA supervision and was regularly inspected, there were also French technicians in constant attendance. The supply of HEU as fuel was carefully staggered and used fuel had to be returned to France, making a diversion of fuel into a weapons programme obvious and therefore unlikely - any noticed diversion would have meant an immediate end to further supplies. Similarly the clandestine irradiation of uranium could not have taken place undetected, the repeated, slow and costly changing of uranium rods would have been obvious.
The Israelis encouraged an Iranian attack on the site on September 30, 1980 but it had little success. Menachem Begin then authorised a Israeli strike to take place before the reactor fuel was loaded. Flying from Etzion air base on June 7, 1981 a IAF strike force flew 1,100 km across Jordan, Saudi Arabia and into Iraq to bomb the target. Arriving at around 17.30 the reactor site was quickly destroyed. One of the Israeli pilots on the mission was Ilan Ramon, who would later become Israel's first astronaut and die in the Space Shuttle Columbia disaster on February 1, 2003.
The loss of the reactor was a serious blow to the Iraqi nuclear program. France finally declined to assist in the reconstruction of the reactor in 1984. The Iraqi nuclear weapons program was forced to turn to less efficient uranium enrichment processes such as electromagnetic isotope separation (EMIS).
The site was closed and held under IAEA supervision. The Iraqi government made efforts to recover components from the site from September, 1990. But during the Gulf War the site was targeted and from January 17, 1991 the site was bombed on seven different occasions by either F-117s or F-111s until on February 26th the site was judged "severely degraded".