By ROBERT F. WORTH
That position, if maintained, could undermine the entire plan. The French government, a party to the deal, has made it clear that the uranium must be shipped all at once before the end of the year.
Iran has said it will formally respond on Friday to the proposal, which is intended to delay the country’s ability to produce a nuclear weapon for about a year and buy time for a broader diplomatic solution to the nuclear standoff.
On Tuesday, Alaeddin Borujerdi, the head of Parliament’s national security and foreign policy committee, said that if Iran agreed to ship its uranium abroad, to be further enriched for use to produce electricity, “this must not happen in one go,” and that the fuel must be shipped in installments, according to the semiofficial ISNA news agency.
Mr. Borujerdi also said “our basic opinion” was that Iran preferred to purchase processed nuclear fuel rather than send its uranium abroad for processing. Other officials have made similar comments in recent days, and the Iranian reaction so far appears to reflect Iran’s complex internal politics rather than any clear indication of what the decision will be. The supreme leader, Ayatollah Ali Khamenei, has final authority on state matters and often allows various high-ranking officials to express their views before making a decision.
Mr. Borujerdi’s comments might also be a trial balloon to discern Western responses to possible changes to the plan, analysts said.
United Nations inspectors are now in Iran, visiting a uranium enrichment site near the city of Qum, the existence of which was a state secret until September.
Under the plan, drafted by Iranian and Western negotiators in Vienna last week, Iran would ship 2,645 pounds of low-enriched uranium to Russia for further processing. That amount, representing most of the country’s known stockpile of low-enriched uranium, would take about a year to replace.
In the meantime, Iran would not have enough nuclear material to build a weapon, and there would be more time to prepare an international agreement on Iran’s nuclear ambitions. The uranium would be returned to Iran in the form of fuel rods, usable only in a civilian nuclear facility and not for weapons.
Some Iranian officials appear to fear that the plan could be a trap and that the fuel might not be returned. The proposal to ship it in installments might be an effort to alleviate that fear.
But American officials are equally concerned that the Iranians are planning to run out the clock and continue processing uranium so that they can either build a weapon or attain “breakout capacity,” the ability to build one within a few months. Some diplomats involved in the negotiations are also concerned that Iran may have more nuclear fuel in its stockpile than it has acknowledged, and may indeed already possess breakout capacity.
If Iran formally proposes to ship its uranium in installments, Western powers that brokered the proposed deal in Vienna are likely to balk, said Valerie Lincy, a senior researcher with the Wisconsin Project on Nuclear Arms Control, a Washington-based nonprofit group that works for arms limits.
“One of the problems would be that a part of the stockpile would remain in Iran, so the risk of breakout capacity would still be there,” Ms. Lincy said. Much would depend on how much low-enriched uranium remained in Iran, she added.
She also noted that Iran was continuing to produce low-enriched uranium, and could continue to do so rapidly even as it shipped almost equal amounts of fuel out in installments, making the deal largely meaningless.
