How brittle is 'too brittle'?: Comparative mechanical assessment of silicon carbide and post-quench steam-oxidized zirconium alloy cladding

This study compares the ductility of Triplex SiC composite cladding to established post-quench ductility (PQD) limits of zirconium alloys under Design Basis Accident conditions. As-received SiC cladding exhibits brittleness exceeding the limits permitted for significantly oxidized zirconium alloys under current design basis accident (DBA) safety standards. Although Triplex SiC cladding experiences only minimal oxidation-induced ductility loss with great capability for coolable geometry retention, this advantage is overshadowed by its inherent brittleness. It implies that deployment of SiC cladding requires substantial revisions to current regulatory frameworks to accommodate the unexperienced brittleness of SiC composite cladding, even under steady-state reactor operations.