A technical glitch was reported at the north German Brokdorf nuclear power plant as a short circuit of a malfunctioning pump caused a fire in the facility, press reports Friday.
According to the nuclear supervisory board, workers at the plant managed to extinguish the fire.
Two of the four emergency power wires had to be turned off in a bid to repair the short circuit.
Last month, a fire broke out at a deactivated nuclear power plant near Hamburg which had been the scene of repeated mishaps in the past, press reports said Monday.
According to the operator of the Krümmel atomic reactor, the fire department of the nuclear plant had to be called in to extinguish the fire at a ventilation system.
No one was injured and no radioactive material was released.
The reactor building had to be temporarily evacuated.
Owned by the Swedish Vattenfall company, the Kruemmel nuclear plant was shut down after a fire broke out in a transformer on June 28, 2007.
The nuclear supervisory board of the north German state of Schleswig-Holstein announced earlier that the Kruemmel nuclear plant would not be activated again before the middle of May.
The Kruemmel reactor came online in 1983 and supplies about 30 percent of the region's power, according to Vattenfall Europe AG, which jointly owns the plant with E.ON AG.
The German government cited last year "considerable security deficits" in some of the country's 17 nuclear reactors following a series of recent incidents and technical blunders.
Berlin had also asked the Vienna-based International Atomic Energy Agency (IAEA) to review all security and technical supervisory aspects of its nuclear program.
Germany's nuclear power plants have reported 944 incidents between the period of early 2000 and late 2006, according to statistics released by the Federal Office for Radiation Protection (BfS).
Meanwhile the number of registered breakdowns in German nuclear power plants since 1993 stand at 1,945.
The latest figures point to the high number of incidents in especially older nuclear power plants.
Topping the list are two nuclear power facilities, Brunsbuettel and Neckarwestheim both of which were built in 1976.
Brunsbuettel reported 437 and Neckarwestheim 1 registered 408 mishaps.
"Older nuclear reactors are definitely more vulnerable than younger ones," BfS spokesman Joachim Gross was quoted saying.
One-third of German atomic reactors are reportedly shut down because of either technical problems, repair work or system check-ups.
German nuclear power plants account for 26 percent of the nation's energy consumption.
Faced with a gradual phase-out by 2021, Germany's nuclear reactors are still working at full strength, having raised their electricity production in 2006.
German atomic power plants generated 167.4 billion kilowatt hours of electricity last year, up from 163 billion kilowatt hours in 2005.