Silicon-carbide composite materials for the ARIES-I reactor study

Abstract

Thr ARIES-I tokamak is a conceptual reactor drsigii based on advanced technology and modest extrapolation from the present clay physics database. The ARIES-I blanket ntilizes SiC'/SiC' composite materials as structural material with lieliiini gas as the coolant. Until recently the brittle failure behavior of monolithic ceramic materials has posed a i~rohlem for rising ceramics as structural materials. Recent development s in nia~iiifact uring and processing of fiber-reinforced rerainics make Si<'/Sic' composites a promising candidate for future power plants. Silicon carbide composites are advantageous from a safety and waste disposal stand point because of the low activation and their very low decay after-heat respect ively. The tlienno~~iechanical properties and neutron irradiation response of SiC/SiC composite materials are reviewed. Composite design eqciations are used to approximate a window of allowable design stresses for the first wall and blanket strnctiire of the ARIES-I tokamak reactor. The ANSYS finite eleiiient structural analysis code is used to analyse the thermal and mechanical hrliavior of the first wall under normal operating conditions. [t is roncluded that with minor extrapolations from todays manufacturing experience, SiC/SiC composites offer a viable striictitral material choice thus improving the safety and environmental aspects of future fusion power plants compared with coal or imclear.

Blanket design for the ARIES-I tokamak reactor

“…The main method used to improve the strength and fracture toughness is through fiber reinforcement. Different methods can be used to infiltrate the Sic into a fibrous Sic preform [7]. Recent advances in Sic composite manufacturing processes have greatly improved the failure mode behavior, strain tolerance, and fracture toughness of these ceramics.…”

“…Using a finite element calculation, the detailed structural design of the first wall was analyzed. It was shown that the maximum local stress can be designed to below the 180 MPa design limit of the Sic composite material [7].…”

“…The blanket module is designed to 1mmTubeW Slruchrrr SChemaliC I withstand the gas pressure of 5 MPa The blanket module can be fabricated by first forming the complete poloidal segments of the module, with the inclusion of flow channels and structural supports before the high-temperature Sic infiltration and brazing process. The module can then be filled with the sphere-pax: Be metal and Li4SiO4 pellets into their respective radial zones [7]. These multiplier and breeder zones are cooled by helium coolant channels.…”