Iran nuclear program: 5 key sites

Iran’s nuclear program is the subject of constant scrutiny by the international community. Here are five of Iran's most important nuclear sites.

5. Tehran Research Reactor

The Tehran Research Reactor is a light-water nuclear reactor given to Iran by the US in 1967, along with weapon-grade uranium fuel, when Iran was ruled by the pro-West Shah. After the Islamic Revolution in 1979, with Iran no longer able to procure the necessary grade fuel from either the US or Europe, the reactor was modified to use fuel of just below 20 percent enriched uranium.

Iran ran out of fuel shortly in 2011. When it made a request to acquire more, the IAEA crafted a fuel-swap deal in October 2009, in which Iran would hand over the bulk of its homemade low-enriched uranium to be converted by Russia and France into the 20 percent fuel needed. Iran initially agreed, then rejected the deal, prompting several other plans to date that have all failed.

Iran has since stated it would make the fuel itself, despite technical hurdles that prevent all but a few countries in the world today from manufacturing such fuel. Iran nevertheless began enriching uranium to 19.75 percent for the fuel – taking one big step closer, technically, to bomb-grade levels.

In Feb. 2012, Iran announced that for the first time it was loading domestically made nuclear fuel rods into the Tehran Research Reactor.

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