1.1 This document is a guide to preparing material specifications for silicon carbide fiber/silicon carbide matrix (SiC-SiC) composite structures (flat plates, rectangular bars, round rods, and tubes) manufactured specifically for structural components and for fuel cladding in nuclear reactor core applications. The SiC-SiC composites consist of silicon carbide fibers in a silicon carbide matrix produced by liquid infiltration/pyrolysis and/or by chemical vapor infiltration.

1.2 This guide provides direction and guidance for the development of a material specification for a specific SiC-SiC composite component or product for nuclear reactor applications. The guide considers composite constituents and structure, physical and chemical properties, mechanical properties, thermal properties, performance durability, methods of testing, materials and fabrication processing, and quality assurance. The SiC-SiC composite materials considered here would be suitable for nuclear reactor core applications where neutron irradiation-induced damage and dimensional changes are significant design considerations. (1-8)2

1.3 The component material specification is to be developed by the designer/purchaser/user. The designer/purchaser/user shall define and specify in detail any and all application-specific requirements for design, manufacturing, performance, and quality assurance of the ceramic composite component. Additional specification items for a specific component, beyond those listed in this guide, may be required based on intended use, such as geometric tolerances, permeability, bonding, sealing, attachment, and system integration.

1.4 This guide is specifically focused on SiC-SiC composite components and structures with flat plate, solid rectangular bar, solid round rod, and tubular geometries.

1.5 This guide may also be applicable to the development of specifications for SiC-SiC composites used for other structural applications, discounting the nuclear-specific chemical purity and irradiation behavior factors.

1.6 Units-The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.