Status of the design and performances of the WCLL test blanket module for ITER-FEAT

The water-cooled lithium–lead (WCLL) DEMO blanket is one of the two European blanket lines to be further developed with the aim, in the short term, of manufacturing a DEMO blanket mock-up, named the test blanket module (TBM) to be tested in ITER-FEAT. This blanket line is based on reduced-activation ferritic-martensitic steel of the 9% Cr class as structural material, the liquid alloy Pb–17Li as breeder and neutron multiplier and water at typical PWR conditions as coolant. The WCLL TBM is expected to use all technologies required for that concept and is essentially formed by a directly cooled steel box having the function of Pb–17Li container and by a double-walled C-shaped tube bundle, immersed in the liquid metal, in which the water coolant circulates. The design of the TBM and its ancillary circuits is described. Conceptual studies have shown that, in the range of the foreseen heat flux and neutron wall loading in ITER-FEAT, DEMO relevant testing conditions could be reached with a unique reference TBM design by properly adjusting the thermal–hydraulic conditions in both the breeder zone and segment box. A tentative test plan in ITER has been established with the overall objective to evaluate the TBM behavior (e.g. functional, thermal, mechanical, neutronic) in conditions which are, as much as possible, relevant to DEMO.