BERLIN (Reuters) - Chancellor Angela Merkel said on Thursday she aimed to accelerate Germany's move away from nuclear energy after the crisis in Japan and dismissed accusations she may have closed seven atomic plants illegally.
Merkel this week backtracked on an unpopular decision to extend the life of aging nuclear stations, drawing scorn from the opposition which says she is merely trying to avoid a major electoral setback in regional polls this month.
Addressing a rowdy session of parliament, Merkel said nuclear technology remained a transitional source of affordable power while renewable energy sources were developed further.
Under a "moratorium," the government ordered by decree on Tuesday the closure of all nuclear plants which began operating before 1980 for at least three months, so that they could undergo safety checks.
"We will use the moratorium period, which we deliberately set to be short and ambitious, to drive the change in energy policy and accelerate it wherever possible, as we want to reach the age of renewable energy as quickly as possible," she said.
Imposing the moratorium, Merkel suspended a government decision taken only last autumn to prolong the life of Germany's 17 nuclear power plants beyond their original closure dates.
That sudden decision drew criticism from home and abroad.
The former president of the Constitutional Court, Hans-Juergen Papier, pointed out that Germany's nuclear industry was covered by law. "Constitutionally it goes without saying that the federal government cannot order the provisional repeal of a law," he told Handelsblatt newspaper.
Asked if the government's move had been unconstitutional, he said: "Yes, that's how it is."
Amid opposition heckling, Merkel said repeatedly that the catastrophe in Japan, where an earthquake and tsunami provoked a crisis at the Fukushima nuclear complex, meant Germany faced a new situation. Everything had been done legally, she said.
"The nuclear law provides precisely for this: shutting down a plant temporarily until the authorities have achieved clarity about a new situation," she said.
Merkel is under fire even from her own ranks. Speaker of parliament Norbert Lammert, a member of her conservative CDU party, questioned why the Bundestag had not been consulted.
An official in the neighboring Czech Republic also questioned how major decisions could be made when Japanese engineers were still battling to avoid a major nuclear accident.
"We have time to analyze what we can learn from Fukushima," said Dana Drabova, who heads the Czech nuclear safety office.
"But to make hasty decisions when we hardly know what happened in the plant and where improvements should be appears to me rather premature," she told Reuters TV. "Technically, I see no reason for the shutdowns."
Bavaria's Isar 1 reactor is due to go offline on Thursday, its operator E.ON said. [nLDE72G0LK]
It is likely to be followed by EnBW's Neckarwestheim 1, a target of anti-nuclear protests which is in the state of Baden-Wuerttemberg, where Merkel's conservatives face a struggle to hold on to power in a March 27 election.
Defeat in Baden-Wuerttemberg would deliver a psychological blow to Merkel and weaken her coalition. It has already lost its majority in parliament's upper house, where representation depends on the relative strength of parties in state assemblies.
The CDU suffered an electoral thrashing in Hamburg last month and is desperate to hold on to power in Baden-Wuerttemberg, one of Germany's most economically dynamic states and a conservative stronghold for more than 60 years.
Germany will have to boost power production from fossil fuels to compensate for the nuclear closures, and the uncertainty over Merkel's plans pushed up the cost of carbon emission permits to a 2-1/2 year high this week.[nLDE72G0MT]
Additional reporting by Stephen Brown, Tom Kaeckenhoff and Vera Eckert; Editing by Robert Woodward