In-pile tensile creep of chemical vapor deposited silicon carbide at 300 °C

Irradiation-induced creep is one of the key material properties considered in designing structural components for nuclear reactors. This paper presents results for in situ irradiation-induced creep of chemical vapor–deposited 3C silicon carbide studied by instrumented irradiation in the Halden reactor in Norway. The specimens examined were irradiated at 300 °C and up to 2.5 × 10²⁴ n/m² (E > 0.1 MeV) under uniaxial tensile stress of <5 or 100 MPa. Irradiation-induced creep strain was defined as the differential time-dependent strain between the two specimens. Based on the dimensional inspections before and after irradiation, an axial primary creep strain of 0.06% was obtained at the end of irradiation. The lattice constant precisely determined from high-energy x-ray diffraction analysis showed a lattice expansion roughly accounting for the primary irradiation creep strain. Analysis of data from this and previous studies indicates that creep strain is significantly dependent on at least one of the experimental conditions, such as loading mode, neutron spectrum/flux, and material grade.