View of the Areva Tower, the headquarters of the French nuclear reactor maker Areva, at La Defense business and financial district in Courbevoie near Paris near Paris

View of the Areva Tower, the headquarters of the French nuclear reactor maker Areva, at La Defense business and financial district in Courbevoie near Paris near Paris October 21, 2014. Struggling French nuclear engineering group Areva said on Monday its Chairman and Chief Executive Luc Oursel had decided to step down for health reasons. REUTERS/Charles Platiau (FRANCE - Tags: ENERGY BUSINESS LOGO) - RTR4AYWC