Environmental activists waved banner at nuclear plant . The plant 's operations were not affected , officials said . `` Today , militants of various nationalities , coming from all over Europe , protested and occupied Fessenheim , the oldest French nuclear center , '' Greenpeace said on its website . The Fessenheim plant opened in 1977 .
Environmental activists waved banner at nuclear plant . The plant 's operations were not affected , officials said . The Fessenheim plant opened in 1977 .