F4E and ITER IO have concluded the Procurement Arrangement (PA) for the Divertor Cassette Body and Integration. The PA, signed in May and worth 11.2 kIUA of ITER credits, concerns the manufacturing of 60 Cassette Bodies, the mounting of the three Plasma-facing Components (PFCs) on them, and the installation of Diagnostics and instrumentation on a certain number of them. The signing of the PA is an important step in the procurement of the Divertor, a crucial component of the ITER machine.
The implementation of the PA will follow four main phases: firstly, the fabrication and qualification of a Cassette Body prototype and the integration of Plasma-facing Component prototypes on it; secondly, the series production of the Cassette Bodies, factory acceptance tests and delivery to the integration site; thirdly, the assembly of the Plasma-facing Components and Diagnostics (where applicable) on the Divertor Cassette Bodies, thus producing a Cassette Assembly; and lastly final acceptance testing of the Cassette Assemblies and their delivery to the ITER site.
Located at the very bottom of the Vacuum Vessel, the ITER Divertor is made up of 54 remotely-removable Cassette Bodies, each holding three Plasma-facing Components (namely, the inner and outer vertical targets and the dome – see figures 1 & 2). The Cassette Body, to be made of stainless steel 316 L(N) ITER grade, will have a total mass of 4.7 tonnes (7.9 tonnes if the PFCs are mounted on it). The technical design will enable the targets, in their lower part, to intercept the magnetic field lines, and therefore remove the high heat load coming from the plasma. The upper-curved part of the targets will provide a baffle which will limit the neutral particle flow, and prevent it from extinguishing the fusion reaction. The dome will also baffle neutral particles and protect the Cassette Body from direct contact with the plasma. The Divertor Cassette Assemblies will be fixed to the Vacuum Vessel using attachments made out of aluminium bronze.
F4E foresees that the PA will generate two contract lines: one for the fabrication of Cassette Bodies for which a Call for Tender will be launched before the end of 2012; and another one for PFCs and Diagnostics/instrumentation integration and the final acceptance tests, for which a Call for Tender will be launched during the course of 2014.