PARIS--French nuclear engineering firm Areva SA said Wednesday it had temporarily appointed chief operating officer Philippe Knoche as chief executive.

The appointment comes days after chief executive officer Luc Oursel said he was ill and could no longer assume his duties at the state-owned company.

Mr. Knoche will fill the CEO job until the next shareholders' assembly votes on a long-term solution, Areva said in a statement.

Write to Inti Landauro at Inti.Landauro@wsj.com

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