The deal would see Iran exporting its uranium for enrichment
Iran is due to respond to a UN proposal on exporting most of its enriched uranium to Russia for further refining.
The International Atomic Energy Agency (IAEA) draft agreement is aimed at reducing international concern over Tehran's nuclear programme.
Under the deal, Iran would get the fuel it needs for its reactor but would not have enough uranium to make a bomb.
The plan followed talks between the UN, Iran, France, Russia and the US - all except Iran have approved the draft.
Russia was the first country to confirm its support.
Foreign Minister Sergei Lavrov said Russia expected "that not only Iran but the rest of the participants - the countries on whom the realisation of this scheme depends - will confirm their agreement".
French foreign ministry spokesman Bernard Valero said the agreement "suits France" and that Paris had "made this known in an official manner", the AFP news agency reported.
The US National Security Council (NSC) said it had also "delivered its positive response" to the IAEA.
"We look forward to Iran's reply," AFP quoted NSC spokesman Mick Hammer as saying.
Iran has yet to respond and BBC's Bethany Bell, in Vienna, says it remains unclear whether Tehran will be willing to send so much of its nuclear fuel abroad.
Iranian state media quoted an Iranian nuclear negotiator as saying Tehran was "awaiting a positive and constructive response" from the parties.
The unnamed spokesman said the parties were "expected to avoid past mistakes in violating agreements and to gain Iran's trust".
On Wednesday, IAEA director Mohamed ElBaradei said he was feeling "optimistic" after the Vienna talks, which he said had been "very constructive".
Jon Leyne, BBC Tehran correspondent
There has been no word yet from Iran on whether it accepts the key element of the deal - shipping enriched uranium out of the country.
A prominent conservative, the deputy speaker of the Iranian parliament, has said he is opposed to the idea - that shows how difficult it could be for President Mahmoud Ahmadinejad to sell this deal to hardliners in Tehran, even if he wants to.
The main Iranian negotiator has said the deal is a test of the West's commitment to using nuclear power for peaceful purposes. The West will see it exactly the opposite - a test of Iran's intentions.
If a deal is reached it would help the wider negotiations move forward, no deal would make it very hard for the talks to continue. Perhaps more likely is an ambiguous answer from Iran, and another attempt to play for time.
He said the draft agreement "reflects a balanced approach to how to move forward".
"Everybody at the meeting was trying to help, trying to look to the future and not to the past, trying to heal the wounds that existed for many years," he said.
Russian nuclear industry insiders have told the BBC the proposed process would involve Iran sending its uranium to the IAEA, which would forward it to Russia for enriching.
The enriched uranium would then be returned to the IAEA and sent to France, which has the technology to add the "cell elements" needed for Iran's reactor, they said.
This process would enable Iran to obtain enough enriched uranium for its research reactor and for medical use, but not enough to produce a weapon.
Exporting uranium has been seen as a way for Iran to get the fuel it needs, while giving guarantees to the West that it will not be used for nuclear weapons.
Iranian chief negotiator Ali Asghar Soltaniyeh talked positively about a deal, but did not mention uranium export.
Iran insists its nuclear programme is solely for peaceful purposes and that it has the right to enrich uranium.
Western states believe it is attempting to develop a nuclear weapons programme.