ENSA (Equipos Nucleares S.A), as part of the AMW consortium, has achieved a key F4E milestone: the machining of two inner shell plates – the first pieces to be manufactured at ENSA – has been completed. These plates will make up the longest of the segments of the ITER Vacuum Vessel’s sector 3, and measure each 6 metres long, 1.5 metres wide, and has a thickness of 60 millimetres. The plates are made up of the special ITER grade stainless steel. The long length of each plate has entailed a number of challenging steps involving cleaning; cutting and machining of holes which will house the so-called flexible housings (large cylindrical parts which act as bolts); as well as carrying out a wide variety of inspection techniques in order to detect the presence of defects, characterise findings, and measure without causing any damage to the plates themselves (known as Non-destructive Examination – NDE). What makes this work additionally challenging is the fact that the flatness tolerance (the permissible limit or limits of variation in the overall flatness of each plate) is very tight – only a 0.4 mm variation in 6 metres is permitted. With the right techniques, the necessary flatness tolerance for the plates has been achieved, even despite that the longer the length of the piece, the more difficult it is to attain the same overall flatness.
“This milestone achievement shows the commitment of ENSA as part of the AMW consortium to the delivering Europe’s Vacuum Vessel contribution and its key role in the success of the Vacuum Vessel manufacturing”, says Rafael Treviño, Director General of ENSA.
“F4E is pleased with ENSA’s performance: they keep their commitment whilst anticipating and mitigating issues. ENSA has lived up to its reputation of being one of the best European companies in the nuclear field”, says Francesco Zacchia, Project Manager for F4E’s Vacuum Vessel Team.