Luc Oursel cited health reasons, adding that "despite my very strong commitment to Areva, I have had no choice but to hand over my responsibilities at the head of the company and have chosen to take a leave of absence in order to pursue treatment".
Shares in the business, which is the world's largest nuclear company, have fallen more than 40 per cent this year, after a series of financial struggles. In 2011 it took a €2.40bn (£1.89bn) hit on an investment in an African uranium mine, while costs at its Olkiluoto 3 EPR reactor in Finland, which was followed by the Fukushima disaster in Japan, which caused governments to rethink their nuclear strategies.
At the beginning of August the company announced a €694m euro loss, causing shares to fall 20 per cent, its biggest ever one-day fall. Last month, credit ratings agency S&P put it on negative watch, putting its BBB status at risk.