Extended Quality Control Process Applied on TF Strand and TF Conductor Production for JT-60SA Project

In the framework of the JT-60 Super Advanced (JT-60SA) project, as part of its contribution to the Broader Approach Agreement, Europe provides the full toroidal field (TF) magnet system. For this purpose, Fusion for Energy (F4E) is procuring 27 km of TF conductor, which is of cable-in-conduit type, including 486 strands (2/3 NbTi and 1/3 copper) embedded into a rectangular stainless steel jacket. Since the start of procurement in 2010, the totality of strand has been manufactured, and more than half of the total conductor unit lengths have been accepted by F4E. In the course of this material fabrication, a large quality control (QC) program was established to consolidate the robustness of the quality diagnostic of both productions' follow-up. As for the TF strand production, a comprehensive campaign of critical properties evaluation was led to ensure that the T
_CS
(temperature of current sharing) value in the operation condition is compliant with a 1-K temperature margin in the JT-60SA tokamak. From the large amount of data collected over the two-year production period, a statistic analysis is presented in the paper, together with the methodology that was used to build it. As for TF conductor production, the QC database provided hydraulic properties at low Re. In this framework, a covering QC campaign was led to crosscheck the acceptance data and, at the same time, quoting the reliability of acceptance data exploitation for predictive mass flow analyses in operation. An extra QC, including material analyses and quantitative energy-dispersive X-ray (EDX) analysis of both cable and jacket, was also performed. Highlights are mainly put to the scientific approach of the present topics investigated, but together, some considerations on the risk approach are also presented.