Various safety problems have been raised, including weakness in the steel used in the reactor together with heterogeneity of the steel alloy forged high integrity components used in the reactor pressure vessel, that have also been shown to be present in Japanese-sourced components that have entered the French nuclear equipment supply chain. The safety of the Flamanville EPR plant has also been questioned due to the danger of flooding of the kind experienced during the 1999 Blayais Nuclear Power Plant flood. In June 2015 multiple faults in cooling system safety valves were discovered by ASN.