News of the falsified checks at the Philippsburg power plant in Baden-Württemberg led to the state's environment ministry ordering a halt in plans to bring the reactor there back online.
A single worker responsible for regular inspections of radiation monitors had been submitting false reports based on checks he never carried out, power plant operator EnBW said in a statement.
The subcontractor employed to carry out the safety checks may now face legal action, EnBW said, adding that regular inspections were now back in place and that steps had been taken to prevent a repeat of the failure.
But the planned reactivation of the site's second reactor is likely to be delayed past the scheduled date of May 14th as authorities debate how to respond to the revelations.
Green Party nuclear energy spokeswoman for Baden-Württemberg Sylvia Kotting-Uhl called on the federal government to investigate the case.
Meanwhile in neighbouring Hesse, a second nuclear plant just 60 kilometres away from Philippsburg was revealed to have suffered from a near-identical safety failure.
A worker responsible for checking radiation levels at the deactivated Biblis nuclear plant filed faked safety reports throughout 2014 and 2015, an environment ministry spokesman told hessenschau.de.
The operator of the plant and the Hesse environment ministry spotted irregularities in the paperwork that allowed them to discover the problem, the ministry said in a statement.
“The misbehaviour of workers at EnBW should be criticized and investigated,” junior federal Environment Minister Rita Schwarzelühr-Sutter told The Local in an emailed statement.
For now, though, the Berlin Environment Ministry says that the faked safety checks remain a case for regional, not federal authorities.
Nuclear fears still alive
German public opinion has long been leery of nuclear power, which was a powerful driver of the emergence of the Green party as a national political force in the 1980s.
Following the 2011 Fukushima disaster in Japan, the government announced plans to shut down all the country's nuclear plants by 2022 under a policy known as the energy transition (Energiewende).
At the time, nuclear power accounted for around 18 percent of German electricity generation.
As a consequence, the Biblis nuclear plant has been deactivated since 2011, while only one reactor of two is still operational at Philippsburg, with the second slated for shutdown in 2019.
Since 2015's Paris climate conference, Germany is committed to reducing its carbon emissions to five percent of 1990 levels by 2050.
Without nuclear, that means massive investment in renewable energy, which already accounts for 27 percent of power generation in the country.