ITER BREEDING BLANKET DESIGN FOR THE ENHANCED PERFORMANCE PHASE

The International Thermonuclear Experimental Reactor (ITER) breeding b lanket is designed to breed the necessary tritium for ITER operation d uring the enhanced performance phase by replacing the shielding blanke t of the basic performance phase. Similar to the shielding blanket, it has to remove the majority of the fusion power generated by the plasm a and to protect the vacuum vessel and the toroidal field coils from e xcessive nuclear heating and radiation damage. It has to produce a net tritium breeding ratio of more than 0.8 to satisfy the technical obje ctives of the enhanced performance phase. For compatibility with the I TER design and to satisfy the blanket functional requirements, a water -cooled modular solid breeder blanket with a beryllium neutron multipl ier has been selected. Lithium zirconate is the reference breeder mate rial based on the current database. Enriched lithium is used to enhanc e the tritium breeding capability, to reduce the radial blanket thickn ess, to decrease the breeder material volume, to lower the breeder the rmal stresses, and to enhance the shielding capability. Similar to the shielding blanket, the breeding blanket uses Type 316LN-IG austenitic steel structural material. Both forms of beryllium material, porous a nd pebbles, are used at different blanket locations based on di:sign r equirements. This paper is concerned with the design analyses and desi gn selections, including beryllium form, breeder material, tritium bre eding, and heat transfer across the beryllium-steel interface. Also, t he required research and development tasks for the ITER breeding blank et are summarized. (C) 1998 Published by Elsevier Science S.A. All rig hts reserved.