By championing the improved safety and environmental advantages of nuclear energy, Lauvergeon, 47, has become the first lady of fission. The $14 billion company she heads has built a quarter of the planet's nuclear capacity and is currently constructing a reactor in Finland that, when completed later this decade, will be the world's largest. The company is also building plants in China and Japan and hopes to build the first commercial nuclear reactor in the U.S. in nearly three decades. Profits at Areva doubled last year, to $1.3 billion. No wonder Lauvergeon, a onetime civil servant who has been chairman for five years, was given a new five-year contract in July.