PARIS (AP) — The CEO of French nuclear manufacturer Areva is stepping down, saying an unspecified illness has left him unable to do the work.

Monday’s statement from Areva says Luc Oursel recently notified the French government of his decision to take a leave of absence “in order to pursue treatment.”

State-controlled Areva is struggling through a turnaround, complicated by France’s recently announced plans to move away from nuclear energy in the aftermath of the earthquake and tsunami at the Fukushima power plant in 2011.

Under Oursel, Areva has expanded investment in renewable energy, but the sector still makes up a small part of Areva’s business.

Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.