German energy group RWE said Thursday it would file a legal challenge to Berlin's decision to shut down one of its nuclear reactors for three months, a move its rival EON has renounced. "We want to file a lawsuit Friday before the Kassel Administrative Court against the order to shut down the Biblis A reactor for three months," a RWE spokeswoman told AFP, confirming a report due to appear in the German newspaper WAZ. "There are doubts about the legal basis" for the moratorium decided by the government and "we want that the court clears up the situation," added the spokeswoman. The Biblis A reactor was RWE's only reactor hit by the government decision to shut down seven of Germany's oldest reactors for at least three months for security checks that was adopted in the wake of the nuclear crisis in Japan. Another RWE reactor located next to it was already shut down for maintenance. EON said Thursday it did not believe it worthwhile to mount a legal challenge for a moratorium of just three months. German Environment Minister Norbert Roettgen welcomed EON's decision. "I don't think you get a consensus in front of a court," he said on television, speaking before the announcement of RWE's challenge. "It is society and in the end parliament that decides."