French group EDF on Friday announced a two-year delay for its nuclear power plant in Flamanville along with a cost increase, a revelation that could shake the confidence of potential foreign clients in the new generation reactor.

Confirming press reports circulating for the last several weeks, EDF said the plant would begin to produce electricity on a commercial basis in 2014.

It said the facility, located on the Channel coast in Lower Normandy, would now cost 5.0 billion euros (6.5 billion dollars), rather than an initially estimated 3.3 billion euros.

The announcement amounted to new blow for the third generation European Pressurised Reactor (EPR), coming just several months after a French consortium failed to convince Abu Dhabi to buy the EPR as part of a 20-billion-dollar project.

An EPR under construction in Finland by another French group, Areva, has also been hit by delays and cost over-runs.

The former head of Electricite de France, Francois Roussely, in a report earlier this week, said "the credibility ... of the EPR model and the capacity of the French nuclear industry to be able to build new power plants have been seriously shaken" by the problems in Finland and at Flamanville.

The failure to win the Abu Dhabi contract raised questions about the future of the EPR, which is key to France's nuclear power export strategy, notably with regard to its high cost and its capacity, 1,650 megawatts, which is seen by certain clients as too powerful for their needs.

The government has therefore been urging EDF to expand the range of reactors with less capacity.

EDF has officially shown no sign of anxiety.

The EPR at Flamanville is "a prototype," EDF financial director Thomas Piquemal said Friday.

"Prototypes cost more than what comes afterwards."