( Reuters ) - The closure of two northern German nuclear power stations after problems on Thursday could not have come at a worse time for German operators who seek to extend the lifetime of some plants.
Firefighters were still putting out a fire in a transformer substation on the site of the Kruemmel nuclear power generation block some 20 km ( 12 miles) south-east of Hamburg on Friday.
Police said the fire had not affected the 23-year-old reactor and there was no danger of radioactive leaks.
Also on Thursday, a short-circuit at the nearby Brunsbuettel nuclear plant which was built in 1977 switched off that unit, leaving both plants out of action for the time being.
"It is increasingly taxing to ensure the safety of these old reactors," the social minister for the German state of Schleswig-Holstein, Gitta Trauernicht, told German radio.
Trauernicht heads the ministry that supervises nuclear safety in a state whose government is critical of nuclear power.
Brunsbuettel is due to close in 2009 under Germany's nuclear exit programme but its main operator Vattenfall Europe
Only a week ago, Trauernicht declared: "Brunsbuettel is unsuited to an extension" and the federal environment ministry in Berlin rejected Vattenfall's first application.
Ivo Banek, spokesman for Vattenfall, said there was no reason to link Thursday's incidents to the longer-term question of prolonging nuclear plants' lifetime.
"On the contrary, these were defects that could also have happened elsewhere and there is no doubt that managers, security staff and the fire guard had them fully under control," he said.
After last week's rejection of its attempt to transfer production quotas from an idled plant of RWE
In other cases, RWE had its application to keep its Biblis A nuclear plant open beyond 2008 rejected, and south-west German utility EnBW
The ensuing legal tussles take place as Germany's coalition government is deeply divided over nuclear power.
Chancellor Angela Merkel's conservatives mostly support the nuclear industry's attempts to win more production time while renewable energies catch up to become more commercially sound.
But the centre-left Social Democrats mostly oppose nuclear.