CONVERTIBLE LIQUID-METAL BLANKETS FOR ITER WITH PB-17LI AS BREEDING MATERIAL

A convertible blanket concept is proposed for ITER, where, without rep lacement of the blanket structure, a non-breeding Pb alloy is used dur ing the basic performance phase and the eutectic Pb-17Li during the en hanced performance phase. The concept is based on austenitic steel as structural material, an average neutron wall load of 1 MW m(-2) and ei ther helium or water as coolant. The same design concept was used for both coolant options with respect to a stiff blanket segment box, dire ct cooling of the first wall using toroidal ducts, poloidal hairpin tu bes to cool the quasi-stagnant liquid metal and tritium removal outsid e the vacuum vessel. Various design options were considered for the fi rst-wall and pool cooling and corresponding headers. Owing to the diff erent coolant properties, different combinations were selected for the two versions. The performance of the two versions was assessed among other things with respect to tritium breeding and control, reliability and R&D needs.