Vattenfall officials said that Bruno Thomauske, who headed Vattenfall Europe Nuclear Energy (VENE), has been relieved of his duties. Thomauske had faced criticism that he was too secretive about a fire that broke out in the Krümmel nuclear power plant in June.
Johannes Altmeppen, the head of public relations at Vattenfall Europe, has resigned.
Gradual disclosures since June 28, when the company's reactors at Krümmel and Brunsbüttel near Hamburg both had to shut down, have revealed that staff at Krümmel were in crisis as a fire raged in a transformer.
Though neither reactor was damaged and no radioactivity was released, the disclosures have embarrassed Vattenfall.
The Swedish company's Vattenfall Europe subsidiary is one of Germany's four biggest utilities, operating main city grids and numerous fossil and nuclear-powered generating stations.
The company said the removal of Thomauske from his duties took place "in close cooperation with the Swedish parent" and said it would commission an inquiry by scientists and business experts into what had happened.