Experiences and lessons learned during manufacturing of group-Y cryolines for ITER

Abstract

The operation of ITER machine is based on the magnetic confinement which will be achieved using superconducting magnets and cryopumps (clients of cryogenic system). The cryogens will be channelized to the clients with the help of cryolines, referred here as ITER cryolines. The complex network of ITER cryolines is divided into two groups, namely, Group-X cryolines (X-CL) and Group-Y cryolines (Y-CL). The design and manufacturing activities of all cryolines have been finished, whereas, installation activities are presently going-on at ITER site, France.Generally during manufacturing phase, internal components of cryolines shall be integrated and tested to achieve the designed specifications. Before closure of the Outer Vacuum Jacket (OVJ), all the Non-Destructive Examinations shall be completed as per the chosen construction code and the technical & quality requirements.The paper would describe the flow of manufacturing of Y-CL from raw material to CE certification with the experiences gained and lessons learned during the manufacturing activities of the Y-CL and its pre-series cryoline. The paper would also cover the implementation of the stringent technical & quality requirements, e.g. thermal shock test, welder authorization, production proof sample, etc. The lessons learnt during pre-series and initial manufacturing phase were subsequently implemented in the series production of ∼ 3.5 Kms of Y-CL. The paper also highlights the unique issues encountered and resolved during manufacturing and factory testing phases like the necessary parametric controls during Multi-Layer Insulation (MLI) wrapping, protection of sliding spacer and MLI during welding, radiation shield integration, the closure of the OVJ, etc.