STRASBOURG - Energy production has been shut down at France’s oldest nuclear power plant after a pipe defect was discovered, the station’s operators said Sunday. The Fessenheim plant, which is near the Swiss and German borders, was halted on Saturday just before 1900 GMT due to a flaw in a pipe in the machine room, which does not house nuclear material, a statement from energy supplier EDF said. ‘The station’s staff are currently diagnosing the exact cause of this event,’ said EDF, adding the defect had ‘no consequence on the safety of the facility, the environment or staff.’