The EU on Wednesday approved Britain's ambitious plan to build its first nuclear plant for a generation, with French and Chinese help, marking a major victory for nuclear energy three years after the Fukushima disaster.

The bloc's competition watchdog said Britain had "significantly modified" its funding plans for the �16-billion ($26-billion, 18.9-billion-euro) deal in response to concerns about whether aspects of the deal amounted to state subsidies.

The Hinkley Point project, to be built by France's EDF, had encountered fierce resistance from activists and several member states, but a vote by the bloc's 28 commissioners narrowly backed the deal.

It is one of the world's most ambitious nuclear deals and is seen as a key boost to an industry brought to its knees by the 2011 Fukushima meltdown in Japan.

"On this basis and after a thorough investigation, the Commission can now conclude that the support is compatible with EU state aid rules," EU Competition Commissioner Joaquin Almunia said in a statement.

Austria has vowed to fight the decision in court, and other member states have voiced concerns that the project makes a mockery of the EU's bloc's stated policy to promote solar and wind power.

Ireland is particularly concerned as the Hinkley Point site is not far from the Irish coast.

A year ago, the British government signed the huge deal for EDF to build two reactors at Hinkley Point C in Somerset, southwestern England, to meet Britain's future energy needs.

Under the accord, which the EU estimates to be worth 31 billion euros, EDF gets a 45-50 percent stake, China General Nuclear (CGN) and China National Nuclear Corporation (CNNC) will have a combined 30-40 percent and another French firm, Areva, 10 percent.

But the European Commission, the EU's executive arm, launched the probe in late 2013, delving closely into the project's elaborate price guarantee system that critics claim will prove hugely expensive to British consumers for decades to come.

In its revision, Britain promised to limit potential profit for private investors involved in the project, but the overall structure of the deal was left intact.

- 'Sell-out' -

"This is a world record sell-out to the nuclear industry at the expense of taxpayers and the environment," said Greenpeace EU legal adviser Andrea Carta after the decision.

"It's such a distortion of competition rules that the Commission has left itself exposed to legal challenges," he added.

Environmentalists see Hinkley Point as an unnecessary support of nuclear energy just when the use of renewables, such as wind and solar power, is beginning to take hold.

But the EU Commission insists that the choice of energy source, no matter how controversial, is strictly up to the member state.

"The responsibilities are clearly stated. We are fulfilling our duties just as UK authorities fulfil theirs on deciding what they want as investment in their own country," Almunia said in a news conference.

Sources told AFP that 16 votes, one more than the 15 needed, approved the project in a rare occurence of a commission decision going to a vote and not made through consensus.

Austrian Chancellor Werner Faymann said his government would "prepare and file a complaint at the European Court of Justice" to fight the greenlit project.

The EU's decision was backed up "neither by ecological nor economic reasons" and sets a "negative precedent", he said.

In statement, EDF said that the approval followed a "demanding but constructive" investigation and marked "another important milestone" for the project.

"The remaining steps require the conclusion of agreements with strategic and financial partners," EDF said, including a Brussels greenlight for the plant's waste disposal arrangements.