PARIS (Reuters) - France has no option but to extend the lifespan of its nuclear power plants as any investments to renew its nuclear capacity or to increase its reliance on other forms of energy would be too costly and come too late, the French Court of Audit said.
The French independent government body, which is charged with conducting financial and legislative audits, said in a report that a lack of investment decisions to build new reactors meant there were few choices left.
"...In the absence of investment decisions an implicit decision has already been made which commits France either to prolong the reactors' lifespan beyond 40 years or to quickly change the energy mix, which implies more investments," said the report on the costs of the French nuclear power sector.
By the end of 2022, 22 out the 58 reactors in France, the world's most nuclear-reliant country, will have been in operation for 40 years.
The report, published on Tuesday, said that if the reactors' lifespan was limited to 40 years this would mean having to build 11 new-generation reactors by 2022.
"Putting in place such an investment program in the short term is highly unlikely, even impossible ...," it said.
State-owned utility EDF, which operates all of the France's reactors, has said it aims to extend their lifespan to 60 years but there is no official limit to their functioning. The bulk of French reactors were built in the 1980s and 1990s.
The court of Audit also said that to maintain the current level of electricity production, heavy investments would be needed in the short and medium term, including a doubling of maintenance investments, which would in turn push production costs up by 10 percent.
"This means that in the absence of investment decisions an implicit decision has already been made which commits France either to prolong the reactors' lifespan beyond 40 years or to quickly change the energy mix, which implies more investments," the report added.
The Court recommended that the choice of the future of the energy mix should not be made in an implicit manner but that a strategy should be explicitly elaborated, debated and adopted.
The report's conclusions echo a leaked draft government study on Monday, saying that extending the lifetime of France's reactors would be a cheaper investment option to 2035-2040 than building any type of new power plant.
The leaked government study on energy scenarios for France until 2050, due to be published in its final form on February 13, shows that extending the operation of nuclear plants would cost 680 million to 860 million euros per reactor.
That would compare to the roughly 5 billion euros ($6.56 billion) it would cost to build a new-generation reactor such as the 1,600 megawatt EPR reactor constructed by state-controlled Areva.
The Court of Audit report, commissioned by Prime Minister Francois Fillon in May 2011, comes as France's reliance on nuclear power has become part of the country's presidential campaign in the aftermath of Japan's nuclear disaster in March.
While the ruling UMP party plans to maintain the country's nuclear share of 75 percent in the electricity mix, the highest in the world, socialist candidate Francois Hollande said he would bring down that share to 50 percent by 2025.
Hollande, campaigning against President Nicolas Sarkozy, has said that if elected he would close France's oldest plant, Fessenheim, toning down earlier plans as part of a pact with the Green party to shut 24 reactors by 2025.
The Fessenheim plant, one of 19 across the country, houses two 900-megawatt reactors.
France first opted for a full-blown nuclear energy program with minimal public debate after the first oil crisis in 1974 and continued to support nuclear power after the 1986 Chernobyl disaster.
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(Reporting by Benjamin Mallet; Writing by Caroline Jacobs; Editing by Muriel Boselli)