Small punch test for investigating circumferential creep in cladding tubes

•A modified small punch creep test (SPCT) is proposed.•The SPCT isolates the anisotropic creep properties of nuclear fuel cladding tubes.•Semi-cylindrical SPCT specimens are extracted from cladding tubes directly.•A single-dimensional circumferential stress state is achieved during testing.•The SPCT is applied experimentally to actual Fecral nuclear fuel cladding tubes. Several methods have been developed to determine the axial creep properties of nuclear fuel cladding tubes. However, the anisotropic creep properties of nuclear fuel cladding tubes requires that their circumferential creep behaviour be evaluated as well. Nonetheless, this task remains extremely challenging owing to need to employ unaltered cylindrical cladding tube specimens directly and the general low accuracy of the methods developed for this purpose. The present work addresses these issues by developing a modified small punch creep test (SPCT). Equations are proposed to calculate the creep stress and strain of the modified SPCT. The accuracy of the equations is analysed using the finite element method. Finally, the methodology is applied to investigate the circumferential creep behaviour of an FeCrAl nuclear fuel cladding tube experimentally. These results clearly demonstrate that the modified SPCT is suitable for investigating the creep behaviour of irregularly shaped material specimens with anisotropic creep properties. Moreover, the semi-cylindrical specimens employed in the modified SPCT also enable the effective fracture strain of the specimen to be easily determined. [Display omitted]