L Giancarli et al. Fusion Engineering and Design 61-62(2002)307-318 309 Table I Comparison between SiCSic properties assumed in the analysis and typical measured values on present-day industrial composites Key SiC/Sic properties and parameters SCLL blankets(agreed drEAM blanket Typical measured value 3000kg/m3 2500kg/m3 ≈2500kg/m Porosity 00-300GI 200 GPa 0.16-0.18 20 0.18 pansion coefficient 4×10-°FC 4×10-6FC Thermal conductivity in plane(1000 C) ≈20WmK(EOL) 15 and 60 W/m k R 15 WIm K(BOL) (EOL) Thermal conductivity through thickness (1000 C) <20 W/m K ( EOL) 15 and 60 W/m K ≈7.5W/mK(BOL (EOL) Electrical conductivity 500/Q2 m(under irradia- Not applicable 500/@2m(out of irradia Tensile strength 300 MPa 300 MPa 300 MPa Trans-laminar shear strength 200 MPa Inter-laminar shear strength 44 MPa Maximum allowable tensile stress Not used 200 MPa Maximum allowable temperature(swelling basis) 1000 C ≈1100°C Maximum allowable interface temperature with 1000°c( nowing) 800°C( statIc) breeder Minimum allowable temperature( thermal conduc- 600C 600° tivity basis) Cost ≤S400/kg ≈10 times larger Assumed design criteria are slight different for each design. They are given in the appropriate chapters. No validated experimental data are yet available key nfluencing its attractiveness, which can development, testing and validation of accep be identified as 'development risks' and which table joining techniques. Different joining tech define the required r&d program. Most R&D niques can be envisaged: (i) assembling by requirements on SiCSic are common to both He- sewing at textile stage to join the stiffeners to cooled and Pb-l7Li cooled systems [5]. The most the side walls; (ii) sticking and co-infiltration to Important common requirements are join the second wall to the first stiffener;(iii) brazing of finished components to join the improvement of thermal conductivity, espe bottom and the top closure plates and the cially through the thickness, at high tempera different sub modules. A promising brazing under technique using a braze material compatible determination and possible improvement of with SiC, the Brasic@, is currently under devel- maximum working temperature under irradia- 46 tion(swelling, compatibility ); development and validation of appropriate de- Specific r&d items concerning SCll blankets sign criteria (e.g. maximum allowed stresses) are which could ensure reasonable component re liability; determination of the electrical conductivity determination and improvement of the lifetime under irradiation capability of fabrication of components with establishment of the maximum interface tem homogeneous properties and reasonable dimen- perature with Pb-17Li under representative sions, with particular attention to the minimum flowing conditions and irradiation level; in particular verification that no Pb-17Li infiltrakey issues influencing its attractiveness, which can be identified as ‘development risks’ and which define the required R&D program. Most R&D requirements on SiCf/SiC are common to both He￾cooled and Pb/17Li cooled systems [5]. The most important common requirements are: . improvement of thermal conductivity, espe￾cially through the thickness, at high tempera￾ture and under neutron irradiation; . determination and possible improvement of maximum working temperature under irradia￾tion (swelling, compatibility); . development and validation of appropriate de￾sign criteria (e.g. maximum allowed stresses) which could ensure reasonable component re￾liability; . determination and improvement of the lifetime; . capability of fabrication of components with homogeneous properties and reasonable dimen￾sions, with particular attention to the minimum and maximum thickness; . development, testing and validation of accep￾table joining techniques. Different joining tech￾niques can be envisaged: (i) assembling by sewing at textile stage to join the stiffeners to the side walls; (ii) sticking and co-infiltration to join the second wall to the first stiffener; (iii) brazing of finished components to join the bottom and the top closure plates and the different sub modules. A promising brazing technique using a braze material compatible with SiC, the Brasic†, is currently under devel￾opment [4,6]. Specific R&D items concerning SCLL blankets are: . determination of the electrical conductivity under irradiation; . establishment of the maximum interface tem￾perature with Pb/17Li under representative flowing conditions and irradiation level; in particular verification that no Pb/17Li infiltra￾Table 1 Comparison between SiCf/SiC properties assumed in the analysis and typical measured values on present-day industrial composites Key SiCf/SiC properties and parametersa SCLL blankets (agreed values) DREAM blanket Typical measured value Density :/3000 kg/m3 2500 kg/m3 :/2500 kg/m3 Porosity :/5% :/10% :/10% Young’s modulus 200/300 GPa :/200 GPa :/200 GPa Poisson’s ratio 0.16/0.18 0.20 0.18 Thermal expansion coefficient :/4/106 /8C 3.3/106 /8C 4/106 /8C Thermal conductivity in plane (1000 8C) :/20 W/m K (EOL) 15 and 60 W/m K (EOL) :/15 W/m K (BOL) Thermal conductivity through thickness (1000 8C) :/20 W/m K (EOL) 15 and 60 W/m K (EOL) :/7.5 W/m K (BOL) Electrical conductivity :/500/V m (under irradia￾tion) Not applicable :/500/Vm (out of irradia￾tion) Tensile strength 300 MPa 300 MPa 300 MPa Trans-laminar shear strength / / 200 MPa Inter-laminar shear strength / / 44 MPa Maximum allowable tensile Stress Not useda 200 MPaa Unknowna Maximum allowable temperature (swelling basis) :/1000 8C :/1100 8C :/1000 8C Maximum allowable interface temperature with breeder :/1000 8C (flowing) / :/800 8C (static) Minimum allowable temperature (thermal conduc￾tivity basis) :/600 8C :/600 8C :/600 8C Cost 0/$400/kg / :/10 times larger a Assumed design criteria are slight different for each design. They are given in the appropriate chapters. No validated experimental data are yet available. L. Giancarli et al. / Fusion Engineering and Design 61/62 (2002) 307/318 309