The firm is fighting the temporary closure of Biblis A plant in Hesse. Renowned legal experts had doubts whether the closure was legal, a company spokesman said late on Thursday.
“We want to clarify that in court,” he said.
The firm will lodge its complaint on Friday to the Kassel administrative court. The spokesman meanwhile said RWE welcomed the announced safety checks on all 17 nuclear power plants.
In the wake of Japan's nuclear crisis following the devastating tsunami of three weeks ago, Chancellor Angela Merkel announced that Germany's seven oldest reactors would be closed for three months and the government would conduct a review of nuclear policy over the same period. All nuclear plants would be given fresh safety checks.
The government used the nuclear energy law to back up its decision. According to this law, authorities can call for a suspension if there is deemed to be a danger to life, health or material assets.
Merkel was widely criticized for the suspension, which was a U-turn on her previous policy of extending the lifetimes of nuclear reactors by an average of 12 years. Critics accused her of playing politics ahead of key state elections.
One of its competitors, E.ON, announced it would not mount a challenge against the temporary closure of its reactors Isar I and Unterweser.
“Despite the doubts about the legality, legal disputes should be at the forefront during the moratorium,” the company announced.
E.ON said it wanted to foster a constructive debate rather than rely on a legal challenge.