PARIS (Reuters) - France's energy minister said on Sunday that the cost of maintaining older reactors would be factored into any decision on the future size of its large and aging nuclear power fleet.
The government already plans to shut the Fessenheim plant on the German border as part of a pledge to bring down atomic energy to 50 percent of French power output by 2025 from the current 75 percent, the highest share in the world.
But it has skirted the issue of whether to extend the operating life of its 58 nuclear reactors, which state-owned utility would like to prolong from 40 years to up to 60 years.
"Investments in reactors at the oldest plants don't last forever. You then have to re-invest and that is very expensive," Energy Minister Segolene Royal told France 3 television.
"If it costs a lot more to carry out maintenance to make older plants secure, it would be better to build renewable energy installations," she said.
France, like other European countries, faces rising costs to maintain a nuclear fleet with an average age of about 30 years. EDF has estimated that extending the life of the plants would cost 55 billion euros.
About half of its reactors are due to reach the current 40-year limit during the 2020s. French nuclear watchdog ASN has said it will give an initial opinion on the issue next year.
Royal is steering through parliament an energy transition bill that introduces a cap on nuclear power production, which would force EDF to close an equivalent capacity when it launches the 1,600 megawatt Flamanville reactor, due in 2016.
She said this week the government could choose to close another site than Fessenheim but dismissed as "fanciful" a 5 billion euro estimate made by two parliamentarians for the cost of closing Fessenheim.
(Reporting by Gus Trompiz and Michel Rose; editing by Jane Baird)