New statistics cited by broadcaster ARD from the Environment Ministry, which is responsible for reactor safety, showed that the number of “component and structural defects that required notification” has surged since 1994.
“An observed trend in the numbers is reason for deeper investigation,” the Federal Office for Radiation Protection (BfS) told the station.
Of the country's 17 nuclear power plants, Krümmel near Hamburg, which was shut down briefly in July 2009 due to safety issues, had the highest number of reported technical defects at 82. That plant went online in 1984.
Krümmel was followed by Brunsbüttel, built in the mid-1970s in the state of Schleswig-Holstein, which reported 80 such problems.
Hesse's Biblis B and Biblis A, constructed in the 1970s, reported 78 and 66 safety issues respectively.
Meanwhile two other plants built in the 1970s, Neckarwestheim II in Baden-Württemberg and Isar II in Bavaria, reported 19 and 20 problems.
The statistics were gathered in response to an inquiry by Green party parliamentarian Sylvia Kotting-Uhl, ARD said. As the party's expert on atomic energy policy, the politician told ARD that if the government took the “susceptibility of old reactors” into account the extension of their use would be irresponsible.
In March, Munich daily Süddeutsche Zeitung reported that Chancellor Angela Merkel's centre-right coalition is considering waiting to turn off the last reactor until some 30 years later than the 2020 cut-off date as decided by her predecessor's centre-left government in 2001.
Such a move would go against Environment Minister Norbert Röttgen, who has advocated a nuclear power extension of just eight years, or until 40 percent of country's energy could supposedly be derived from renewable sources. The minister has also said that the plants were not built to operate for so long, explaining they were intended to run “not for 60, but 40 years,” the paper reported.
Current law stipulates that plants must be shut down after they have provided 32 years of service, which would put the final closure of the country's reactors at around 2022.
There is currently no research that proves reactors can safely operate for 60 years, the paper said.
The coalition made up of Chancellor Angela Merkel's conservative Christian Democrats and the pro-business Free Democrats plans to finalise its energy agenda in October.