Europe pre-qualifies for the procurement of the ITER Blanket First Wall and Divertor

When it comes to multi-parties shared procurement packages of high technology, the Domestic Agencies (DAs) in charge of the procurement package must go through a qualification process in order to demonstrate their technical capability to carry out the procurement with the required quality and in an efficient and timely manner.

Fusion for Energy, in charge of the procurement packages for the Blanket First Wall (FW) and Divertor systems, has therefore had to undergo the corresponding qualification processes.  For the Blanket First Wall (the component in the tokamak that faces the plasma) the qualification process consists of two stages: a mock-up qualification stage and a semi-prototype qualification stage. The first stage aims at demonstrating in particular the know-how to assemble beryllium tiles onto a copper alloy and stainless steel bi-metallic structure. For the divertor system, for which all the DAs in charge of the procurement benefit from a longer development experience, there has been just one stage of manufacturing and testing of medium-scale qualification prototypes made from both carbon fibre composite (CFC) and tungsten (W) armour materials.

For the Blanket First Wall, the performance of the qualification tests for stage 1 have been shared between the US and the EU; at the Sandia National Laboratory (SNL) for the US and at the Nuclear Research Institute (NRI) in the Czech Republic and the Forschungszentrum Juelich (FZJ) in Germany for the EU. At the SNL facility, the qualification test programme consists of the performance of 12,000 cycles at 0.88 MW/m2 for 1.6 minutes followed by 1000 cycles at 1.4 MW/m2, while the EU tests consist of the performance of 12,000 cycles at 0.62 MW/m2 for 5 minutes (at NRI) followed by 1000 cycles at 1.75 MW/m2 (at FZJ). Both the EU FW mock-ups which were manufactured by the CEA Grenoble, successfully achieved the above test programme. Additional tests were performed to assess the limit of the mock-ups and tests were performed for 200 cycles at 1.7 MW/m2 at the SNL and for 100 cycles at 2.25 MW/m2 plus 100 cycles at 2.75 MW/m2 at FZJ (5 times more than the present ITER requirements). Tests were stopped so as not to exceed the maximum acceptable beryllium temperature in the test facilities. Europe is the first ITER party to have passed this first stage of the ITER FW qualification programme. The programme is still in progress for the five other DA candidates for the procurement of the FW, namely China, Korea, Japan, Russia and the US.

For the divertor, the qualification tests were performed at the TSEFEY test facility of the Efremov Institute in St Petersburg, Russia. To qualify, each DA candidate for the procurement of divertor systems namely the EU for the Inner Vertical target, Japan for the Outer Vertical Target and Russia for the Dome have had to supply at least 2 qualification prototypes. All the three EU qualification prototypes, two manufactured by Plansee SE, and one manufactured by Ansaldo Richerche, have successfully passed all the fabrication acceptance criteria and the high heat flux test requirements namely 1000 cycles at 3 MW/m2 plus 1000 cycles at 5 MW/m2 for the W part and of 1000 cycles at 10 MW/m2 plus 1000 cycles at 20 MW/m2 for the CFC part. The EU, Japan and Russia have all passed the qualification test programme.