Aging effect on the thermal transient behavior of the fuel cladding of a sodium-cooled fast reactor

The transient behavior of the fuel cladding of a sodium-cooled fast reactor (SFR) is one of the main design issues concerning the safety of a reactor. The safety margin of the cladding during transient events has been widely studied in the past. However, previously, the transient testing was conducted using as-received specimens (and not aged specimens). For ensuring safety margin of the fuel rod of an SFR, the effect of aging on the transient behavior of the fuel cladding should be considered. This study examines this effect on the transient behavior of HT9 cladding by correlating between the UTS and the result of the ramp test and proposes a modified Dorn parameter that reflects the aging effect. At 100 MPa of the hoop stress, the modified Dorn parameter, which reflects an aging effect, is 7.7266 × 10−14 and the Dorn parameter of as-received specimen is 1.749 × 10−12. This results in the enhanced safety during transient event by considering aging effect.