PARIS (AP) — As Europe struggles through a major heatwave, the French energy company EDF says it has halted a fourth nuclear reactor, this time one at the country's oldest nuclear plant at Fessenheim in eastern France. In a statement, EDT said the Fessenheim nuclear reactor was temporarily shut down Saturday. Since Thursday, four French nuclear reactors in three power plants near the Rhine and the Rhone Rivers, including Fessenheim, have had to be temporarily shut down.