The French nuclear power station of Fessenheim, at the center of anti-nuclear demonstrations, was shut down after more than four decades.
The division plant near the borders of Germany and Switzerland produced 70% of the energy needs of the Alsace region.
The closure of Fessenheim raises questions about how the energy deficit will be filled and the fate of local jobs.
France is committed to reducing its dependence on nuclear power by shutting down 12 nuclear reactors by 2035.
The country depends on nuclear power for 70% of its electricity, a figure that will be cut in half over the next 15 years.
The first Fessenheim reactor was shut down in February and its second reactor was shut down at 11:00 p.m. GMT on Monday. Over the next three years, the spent fuel will be removed, and then it will take another 15 years to completely dismantle the plant.
The state electricity company EDF said it was the first time that a pressurized water reactor had been shut down and completely dismantled. France still has 56 reactors of this type.
Why was Fessenheim so controversial?
Environmental activists have targeted the plant on the Rhine for decades, complaining that it is located in an area prone to seismic activity and is at risk of being flooded.
Among several security failures over the years, cracks were found in the reactor cover and internal flooding in 2014 forced an emergency stop. The security of Fessenheim was examined in the light of the Fukushima collapse in Japan in 2011 and the accident intensified the campaign to close it.
Last year, Fessenheim – which opened in 1977 – was one of six reactors EDF has acknowledged to have manufacturing problems, while maintaining that they are all ready for use.
The decision to close Fessenheim came under the presidency of François Hollande and was confirmed two years ago by President Emmanuel Macron.
Why the locals are unhappy
The Fessenheim nuclear power plant is the largest source of jobs in the region, and the CGT union has said it looked like “economic, social and ecological genocide”.
Mayor Claude Brender said it was a big blow to the region. “It is the end of a beautiful 50-year relationship between a region and its nuclear power plant,” he said on French television.
He said 1,000 jobs would be lost at the plant itself and another 1,100 depended on the work done in Fessenheim.
He said it would also be a blow to the environment as it would now have to import electricity from Germany to replace the electricity supplied by Fessenheim. Half of this energy comes from fossil fuels, he said.