Technical woes slow Iran atom fuel drive-diplomats

VIENNA, July 11 (Reuters) Technical glitches appear to have slowed down Iran's nuclear fuel-enrichment programme and put on hold plans to expand it, diplomats today said.

Serious problems in mastering enrichment technology could diminish the sense of urgency over Iran's case cultivated by its arch-foe the United States, but questioned by Russia and China which oppose sanctions options mooted by Washington.

Iran today rejected Western pressure for an immediate response to an offer of incentives to suspend uranium enrichment and defuse a crisis over suspicions that its professed civilian nuclear energy drive is a camouflaged atomic bomb project.

Washington responded by reminding the major powers that they had resolved to deal with Tehran at the United Nations Security Council if it did not give a timely response to the offer.

In April, Iran enriched raw uranium to the level needed to fuel nuclear power plants for the first time, but far short of the threshold suitable for a warhead. It began a second round of feeding uranium into centrifuge enrichment machines on June 6.

But since then, some Western diplomats in Vienna accredited to the UN nuclear watchdog agency said technical problems had apparently beset Iran's cascade of 164 interconnected centrifuges at its Natanz pilot plant, impeding production.

''We have been told of problems from people in a position to know. It's a slowdown in the process although we haven't been able to quantify it yet,'' said one diplomat, who like others asked for anonymity due to the topic's political sensitivity.

''We have heard ... that plans for a second and third cascade of 164 are on hold and that the attrition rate in the first cascade is relatively high,'' another diplomat told Reuters.

An EU diplomat said the glitches arose from sloppy quality control and impurities in Iranian-made ''UF6'' uranium gas poured into centrifuges. ''Their success in April was apparently done with higher-grade, imported Chinese UF6,'' he said.

The first diplomat said there were unconfirmed reports that the first cascade, the basis for Iranian plans to install 3,000 centrifuges by 2007, had a ''failure rate of up to 50 per cent''.

''The reasons for the delays are definitely not political, that is, it's not like it's an Iranian goodwill signal as they go into negotiations with the EU,'' he said.

Mark Fitzpatrick, analyst with the International Institute for Strategic Studies in London, also said Iran's enrichment programme had bogged down, quoting reliable diplomatic sources.

IRANIANS MUM Asked about the disclosures, Iranian officials at the Brussels talks between chief nuclear negotiator Ali Larijani and EU foreign policy chief Javier Solana declined comment.

Officials at the International Atomic Energy Agency had no comment, citing confidentiality that prevails between periodic reports by IAEA chief Mohamed ElBaradei on Iranian nuclear work.

A senior IAEA diplomat did not confirm or deny that Iranian progress with uranium enrichment was faltering.

''It's hard to make a judgment like this because Iran had not given the agency a schedule of what it intended to do regarding the (current round of enrichment),'' he said.

Centrifuges are prone to breakdown from excessive vibration or pressure and temperature oscillations. Iran would likely have to run thousands of centrifuges for months or years non-stop to prove it could enrich uranium in significant quantities.

The United States and EU allies regard Iranian nuclear activity as an imminent threat to international peace, pointing to Tehran's past cover-up of enrichment research from the IAEA and repeated calls for the destruction of Israel.

ElBaradei has assessed Iran poses no immediate danger. He said last week world powers had ample time to solve the crisis diplomatically, referring to estimates Iran remains 3-10 years away from bomb ''breakout'' capability if it indeed seeks this.

REUTERS SY BD2313