Russian scientist suspected of aiding Iran's nuke effort

PARIS — International nuclear inspectors are investigating whether a Russian scientist helped Iran conduct complex experiments on how to detonate a nuclear weapon, according to European and American officials. As part of the investigation, inspectors at the International Atomic Energy Agency are seeking information from the scientist, who they believe acted on his own as an adviser on experiments described in a lengthy document obtained by the agency, the officials said.

The officials, who spoke on the condition of anonymity because the investigation is under way, said they did not think the scientist was working on behalf of the Russian government.

Still, it is the first time that the nuclear agency has suggested that Iran may have received help from a foreign weapons scientist in developing nuclear arms.

The American and European officials said the new document, written in Farsi, was part of an accumulation of evidence that Iran had worked toward developing a nuclear weapon, despite Iran's claims that its atomic work over the past two decades has been aimed solely at producing electrical power.

In February, in a closed-door briefing at the agency's headquarters in Vienna, its chief nuclear inspector presented diplomats from dozens of countries with newly declassified evidence — documents, sketches and even a video — that he said raised questions about whether Iran had tried to design a weapon.

Among the data presented by Olli Heinonen, the chief inspector, were indications that the Iranians had worked on exploding detonators that are critical for the firing of most nuclear weapons.

When the Iranian envoy at the briefing called the charges "groundless" and protested that the tests were for conventional arms, Heinonen replied that the experiments were "not consistent with any application other than the development of a nuclear weapon," two participants said. Although officials would not say how they obtained the new document, it was first publicly mentioned in an agency report in May as one of 18 documents presented to Iran in connection with alleged nuclear-weapons studies. At the time it was described as a "five-page document in English" about experiments with a complex initiation system to detonate a large amount of high explosives and to monitor the detonation with probes. There was no indication that the document was a translation of a much longer, more comprehensive document in Farsi.

The original Farsi document is described by officials familiar with it as a detailed narrative of experiments aimed at creating a perfectly timed implosion of nuclear material.

According to experts, the most difficult challenges in developing nuclear weapons are creating the bomb fuel and figuring out how to compress and detonate it.

That was followed by an agency report last month that revealed that Iran might have received "foreign expertise" in its detonator experiments. A senior official ruled out the involvement of Libya and the remnants of the network run by Abdul Qadeer Khan, the Pakistani metallurgist who built the world's largest black-market sales operation for nuclear technology. But he would not comment further.

European and American officials now say the "foreign expertise" was a reference to the Russian scientist, but they offered only scant details. They said the scientist was believed to have helped guide Iranians in the experiments, but that he did not write the document.

Russia says it opposes any effort by Iran to obtain a weapon, but cooperation by Russian companies and individuals with some aspects of Iran's nuclear program dates back years.