FLEXURAL STRENGTH OF COMPOSITE TUBES FOR SMR APPLICATIONS USING PURE BENDING: DRAFT ASTM TEST METHOD

摘要

US DOE is planning to use advanced materials for the core and the reactor unit components in various advanced Small Modular Reactor (SMR) concepts. Ceramic matrix composites (CMC), in particular silicon carbide (SiC) fiber SiC-matrix (SiC/SiC) composites, could revolutionarily expand the design window for various components in terms of operating temperature, applicable stress, and service life, as compared to heat-resistant metallic alloys, while significantly improving safety margins and accident tolerance. Examples of CMC tubular components include control rod sleeves, control rod joints, and fuel rods. Anticipated failure modes for these components include axial and hoop tension, axial flexure, axial and diametral compression, and axial shear. An ASTM draft test method has been developed and submitted for full-consensus ballot to determine the flexural strength of composite tubes subjected to pure bending. Numerical modeling and empirical tests of composite tubes provided validation of the parameters specified in the test method. The draft test methods addresses the following experimental issues - test specimen geometries/preparation, test fixtures, test equipment, interferences, testing modes/procedures, data collection, calculations, reporting requirements, precision/bias.