A generic defect in emergency core cooling systems at five 1300MW PWR reactors has been discovered. The defect involves valves on the circuit that recirculates water from the containment sump to the containment spray and safety injection systems. The French regulatory agency, DSIN, has asked Electricite de France to rapidly evaluate the safety of reactors at the Belleville, Cattenom, Golfech, Nogent and Penly plants.