(dpa) - A fire broke out Monday in a ventilation system at an idled German nuclear power station which anti-nuclear groups allege is unsafe.
The plant operator, the Swedish-owned Vattenfall electricity company, said the Kruemmel power station's own fire brigade put out the fire, which it described as the smouldering type, with no flames.
Vattenfall spokesman Ivo Banek said the reactor building at the site, near the port city of Hamburg, was evacuated during the emergency but had since been re-opened.
There was no release of any radioactive substance and nobody was injured. A filter pad in a sensor cabinet in an exhaust duct had begun to smoulder.
The plant, one of 17 nuclear power reactors still operable in Germany, has been shut down since its main transformer in a separate building caught fire on June 28 last year. There was no radioactive release then.
Worried that public opinion in Germany has been becoming more favourable to nuclear power, Greenpeace and other anti-nuclear groups said the incident last year proved nuclear power was fundamentally unsafe.
Germany generates more than 20,000 megawatts of electricity through nuclear power annually, around a quarter of its needs. Under sunset legislation, Germany is to phase out all its nuclear power stations by 2022 and is building coal plants to replace them.
Another Hamburg area Vattenfall nuclear plant, at Brunsbuettel, is also out of commission after a short-circuit, also on June 28 last year.
Under pressure from the media and public, regulators have declared zero tolerance and demanded perfect repairs of all defects at both plants. They said last month the work at Kruemmel would not be complete till mid-May.
Schleswig-Holstein state nuclear regulators in the capital Kiel confirmed there had been no radioactive release during Monday's incident, but opened an inquiry.
Banek told Deutsche Presse-Agentur dpa the cause of the latest fire was still being investigated and it was unclear if this would affect the Kruemmel plant re-opening.