Q+A - Deal to ease nuclear tension with Iran in trouble

By Mark Heinrich

(Reuters) - A draft deal to start defusing nuclear tension between Iran and big powers has foundered in rows over details and goals, reflecting mistrust and an Iranian tendency to play for time.

The breakdown of a draft plan for Iran to part with stocks of potential nuclear bomb material in exchange for fuel to run a nuclear medicine site has prevented follow-up talks on a broader solution to Iran's contested nuclear programme.

* HOW DID THE PLAN ORIGINATE?

Iran is running out of specially fabricated fuel imported in 1993 to run a Tehran research reactor that produces radioactive isotopes for cancer treatment. The seeds of a deal were planted when world powers saw an opportunity to reduce the risk of Iran using its enriched uranium stockpile to develop atomic bombs.

In talks with six world powers in Geneva on October 1, Iran agreed in principle to send the bulk of its low-enriched uranium (LEU) to Russia and France for further processing and conversion into fuel plates for the Tehran reactor, Western officials said.

* HAS THE FUEL PLAN ADVANCED TOWARDS FRUITION?

No. Iran balked at finalising details at October 19-21 talks in Vienna with the other parties presided over by Mohamed ElBaradei, head of the International Atomic Energy Agency (IAEA). To knock heads together, he drafted a plan prescribing that Iran send out 75 percent of its LEU stocks by the end of this year and get it back as fuel for the medical reactor before its reserve peters out about a year from now.

The United States, which would upgrade the reactor's safety gear and instrumentation under the deal, and France and Russia swiftly endorsed ElBaradei's draft. Iran called for amendments and more talks, but left unclear what its bottom line was.