AE Crack Initiation and Propagation Detection in High Pressure Burst Testing of SiC_f-SiC_m Composite Nuclear Fuel Cladding

摘要

Silicon carbide fiber reinforced silicon carbide matrix (SiC_f-SiC_m) composite tube is being developed as an accident tolerant fuel cladding material for light water reactors. The mechanical robustness of the material is of critical importance to ensure that the nuclear fuel and fission products are contained during both normal operation and accident conditions, such as the loss of coolant accident (LOCA) encountered in Fukushima Daiichi Plant. We report the development and application of a high pressure burst testing method to evaluate the mechanical robustness of SiC_f-SiC_m composite cladding. The internal high pressure is generated using a rubber tubing placed within the SiC_f-SiC_m sample tube. A unique test rig was designed to seal the ends of the rubber tubing while pressurizing it up to 2000 bar by hydraulic oil. The expanding rubber tubing confined by the SiC_f-SiC_m sample tube thus exerts a controlled uniform internal pressure to the SiC_f-SiC_m sample. The full-field strain distribution of the outside surface of the sample was captured by 3D digital image correlation (DIC) method. The acoustic emission (AE) technique was used to evaluate the strains-stresses behavior produced during the high pressure burst testing.