The vessel confines nuclear fire. Flamanville’s EPR* vessel in the Manche department in Western France would be subject during its 60 years life time planned by EDF and AREVA to considerable thermal, hydraulic, mechanic, and neutronic stresses. The vessel does not have to be strong; it has to be indestructible.
“The nuclear safety demonstration excludes the breakage of the vessel because no reasonable provision to restrict consequences for the reactor management, for personnel, the population and environment can be defined ” (source: report from Monitoring Group “EPR Vessel” of HCTISN, Haut Comité pour la Transparence et l’Information sur la Sécurité Nucléaire, High Committee for Transparency and Information on Nuclear Safety).
In other words, the breakage of the vessel of the most powerful nuclear reactor ever operated and using Mox (a nuclear fuel mixed of enriched uranium and plutonium) would provoke in Northern Europe a social, economic, and environmental quake worse than that of Fukushima in Asia.
By consequence, the utmost provisions and specifications would have had to apply to the EPR vessel during its conception and construction.
One of these specifications is the avoidance of an excessive carbon presence in the steel, notably in the lid and the bottom of the vessel, considered to be the weakest parts.
The more the carbon content in the steel is high, the more the steel draws nearer to the cast iron and becomes brittle.
The lid and bottom orders of the EPR Flamanville vessel, that should be assumed unfailing, were passed by AREVA in 2005 even though the Creusot steel factory was in technical failure and was in the incompetent hands of the Bolloré group.
In 2006, the French Nuclear Safety Authority interrogated AREVA on the potential to check the homogeneity of the mechanical properties of these crucial castings in the process of being made.
In 2007, a few analyses of lid’s cuttings before its swaging revealed high contents of carbon that pass beyond the qualification criteria.
It was only in 2014 that one extensive research confirmed an excess of carbon in the lids and bottoms of the vessels destined for other EPR projects and made in 2009 and in 2011. At this time, AREVA already bought the Creusot forge from the Bolloré group and the machinery was in technical recovery.
There never was a complete cartography of carbon in the Flamanville EPR vessel. It is an unknown vessel made in a factory in escheat that was irreversibly introduced in the reactor’s building in January 2014.
And it was only in April 2015 that French Nuclear Safety Authority officially communicated these anomalies that place heavy doubt on the capacity of Flamanville 3 to resist the spread of cracks and a the critical breakage.
Robin des Bois, NGO member of HCTISN and of Monitoring Group “EPR Vessel” estimates that in these precarious conditions, the Flamanville’s third reactor should not enter into operation in 2018, nor in 2020, nor ever.
* European Pressurized Reactor, then Evolutionary Power Reactor