The Leibstadt nuclear power plant is seen near Leibstadt, northern Switzerland. Shutting down Switzerland's five nuclear power stations will cost about 20.7 billion Swiss francs (16.8 billion euros, $22.5 billion) and take about 20 years, Swiss authorities said.

Shutting down Switzerland's five nuclear power stations will cost about 20.7 billion Swiss francs (16.8 billion euros, $22.5 billion) and take about 20 years, Swiss authorities said on Thursday.

A study published by the Federal Office of Energy said that the cost had risen by 10.0 percent compared with a 2006 estimate.

The most expensive part of the process will be the long-term management of radioactive waste, it said.

The Swiss parliament approved a phased exit from nuclear energy at the end of September, six months after the Fukushima plant catastrophe in Japan.

Strong to nuclear led to a recommendation that Switzerland's five reactors not be replaced when they come to the end of their operation in 2034.

A huge earthquake and tsunami on March 11 knocked out cooling systems at Fukushima, sending reactors into meltdown and leaking radiation in what was the world's worst since Chernobyl in 1986.