DESIGN REQUIREMENTS FOR SIC SIC COMPOSITES STRUCTURAL MATERIAL IN FUSION POWER-REACTOR BLANKETS/

This paper recalls the main features of the TAURO blanket, a self-cool ed Pb-17Li concept using SiC/SiC composites as structural material, de veloped for FPR. The objective of this design activity is to compare t he characteristics of present-day industrial SiC-SiC composites with t hose required for a fusion power reactor blanket and to evaluate the m ain needs of further R&D. The performed analyses indicated that the TA URO blanket would need the availability of SiC/SiC composites approxim ately 10 mm thick with a thermal conductivity through the thickness of approximately 15 Wm(-1)K(-1) at 1000 degrees C and a low electrical c onductivity. A preliminary MHD analysis has indicated that the electri cal conductivity should not be greater than 500 Ohm(-1)m(-1). Irradiat ion effects should be included in these figures. Under these condition s, the calculated pressure drop due to the high Pb-17Li velocity (appr oximately 1 m s(-1)) is much lower then 0.1 MPa. The characteristics a nd data base of the recently developed 3D-SiC/SiC composite, Cerasep(R ) N3-1, are reported and discussed in relation to the identified blank et design requirements. The progress on joining techniques is briefly reported. For the time being, the best results have been obtained usin g Si-based brazing systems initially developed for SiC ceramics and wh ose major issue is the higher porosity of the SiC/SiC composites. (C) 1998 Elsevier Science S.A. All rights reserved.