Abstract :
As there seems to be a general lack of systematic data about mechanical properties of fuel rod cladding tubes following in-pile operations, the tensile properties (tensile strength, 0.2% offset yield strength, ultimate elongation and uniform elongation) were measured in specimens which had either only been corroded or irradiated, been both corroded and irradiated or were in the initial state. The tensile properties Z of the specimens which had been both corroded and irradiated were calculated from the tensile properties of the specimens which had only been corroded, those which had only been irradiated and those kept in their initial state, in accordance with this formula: Z(corroded + irradiated) = Z(corroded) · Z(irradiated)Z(initial state)
The flat specimens (0.7 × 4 mm) were made of 1.4970 type austenitic cladding tube steel. As with breeder fuel rods, the corrosive medium used was a mix of hyperstoichiometric uranium dioxide and simulated fission products (Cs, I, Te). The strain rate, test temperature, depth of corrosion, simulated burnup, and state of the material parameters were varied systematically. The results of calculations were, on average, in good agreement with the measured results, although some measured values showed considerable variation due to corrosion.
