The diplomats told AFP there was concern since the experiments are allegedly taking place under military supervision, in a country which claims its nuclear program is a strictly civilian peaceful endeavor.
Iran and the European Union are to meet Monday in Brussels to discuss a long-term deal in which Iran would get peaceful nuclear technology, trade benefits and regional security help in return for suspending uranium enrichment, the key part of the nuclear fuel cycle.
The meeting comes as the UN International Atomic Energy Agency (IAEA) is trying to look into claims from the United States and the main exiled Iranian opposition group that Iran is hiding nuclear weapons development at military facilities.
The experiments mentioned by the diplomats, carried out with a neutron generator, are thought to be taking place at an alleged base of Iran’s elite Revolutionary Guards.
They involve the sort of dual-use technology which the Vienna-based IAEA has its eye on but has trouble investigating since it can have civilian as well as military applications.
But a diplomat with close links to intelligence sources said “the combination of the existence of a neutron initiator in a secret facility run by the Revolutionary Guard, making high- and not low-energy neutron experiments is a sufficient good indicator to a suspected military program.”
The experiments may involve beryllium metal, a strategically sensitive item which the IAEA discussed in a report in November on Iran.
A second diplomat cited open-literature reports by Iranian nuclear scientists about work with high-energy neutrons and beryllium in universities in Birmingham, England and in Ferdowsi University in Mashhad, northeast Iran.
The experiments could be a link in alleged weapons activities, involving beryllium and another sensitive metal, polonium.
Iranian officials insist that their their work with polonium is intended to make nuclear batteries, a technology the United States uses in deep-space probes.
But polonium combined with beryllium can be the trigger for an atomic bomb while beryllium can be used to make the reflector around the core of highly enriched uranium that captures neutrons in order to kick off the actual uranium nuclear explosion.
According to the first diplomat, the neutron experiments are being conducted at a Revolutionary Guard base on the outskirts of Tehran “in a neutron generator in an isolated underground building.”
The base is near the Malek Ashtar Technology University where a team of “six senior nuclear scientists and several research assistants” do calculations from the data, the diplomat said.
The diplomat said “fast (high-energy) neutron experiments, involving 14 million electron volts, which are not slowed down by moderators and are performed in a classified facility, are designed for nuclear fission processes, that is nuclear bomb systems.”
An expert close to the IAEA said the watchdog agency was conscious of this work and was measuring it against a scale it has of determining whether to investigate the matter.
The expert said the high-energy neutron experiments can have three applications: to study research reactors which also can use beryllium shields, to study fusion or to develop energy reflectors for atomic bombs.
But the IAEA is limited in its investigations of alleged weapons work since its mandate under the nuclear Non-Proliferation Treaty (NPT) is to guarantee that a country has declared all its nuclear material, diplomats said.
The IAEA, for instance, wants to visit the Parchin military testing site, where US officials say the Iranians may be “dry-testing” atomic bombs using inert uranium.
But the IAEA cannot insist on this since it has no evidence there is nuclear material at Parchin and the agency is asking for the visit as a “transparency” gesture of good faith on the part of Iran.
This is true of most military sites since Iran claims its nuclear program is strictly civilian.
Tehran last month agreed to suspend its sensitive nuclear fuel work as part of a deal with Britain, France and Germany, which staved off moves within the IAEA led by the United States to refer Iran to the UN Security Council for eventual sanctions for its failure to comply with the watchdog.
