France's state-controlled EDF power utility needs to show a new generation nuclear reactors work well, which is not for now the case, new environment minister François de Rugy said in remarks published on Monday.
De Rugy signalled that any decision on whether to build more plants using the European pressurised reactor (EPR) design would be based on economic factors.
The French government is expected to outline in late October a plan to cut the share of nuclear energy in its electricity production to 50 percent from the current 75 percent, the highest level in the world. It has already said it could take a decade more to get there than an initial target of 2025.
Whether that includes the construction of new nuclear reactors has emerged as a politically sensitive issue for president Emmanuel Macron. Last month the previous environment minister, Nicolas Hulot, who was widely viewed as an impediment to the nuclear industry's drive to remain as France's main power supplier, resigned abruptly.
De Rugy, a former Green lawmaker, told Le Monde newspaper in the interview his gut feeling was that nuclear power was not an energy source for the future, but added that there should be no "war of religions" on the issue.
"The important thing is to know the economic data for both nuclear and renewable energies," he said.
Construction of the first plant in France to use an EPR reactor has run billions of euros over budget and is years behind schedule.
Asked whether EDF should build another such plant after it completes the station in Normandy, De Rugy said: "EDF should demonstrate that the EPR works, which is not the case yet. Nobody is able to guarantee a date for its connection to the grid. It also needs to demonstrate the EPR is competitive in terms of costs."
De Rugy also questioned EDF's corporate structure. "I have a few ideas on the issue," he said. "I don't like change for the sake of it but I think the status quo is neither in the state's interest not that of the company."