Failure correlation for zircaloy-2 fuel cladding under high temperature transient conditions.

Abstract

Thermal transient and isothermal tests on unirradiated Zircaloy-2 fuel cladding were conducted by determining short-term failure behaviors depending on temperature transients under constant differential internal pressure cbnditions. Failure data for constant heating rate transient tests were converted to Larson-Miller Parameter (LMP) values on the basis of the life-fraction rule. It was found that failure data for both the transient and isothermal tests were reduced to a single curve described by a correlation between LMP and initial hoop stress. Also, the failure strength during isothermal holdings after thermal transients was successfully evaluated by summing up life-fractions corresponding to each temperature process, using the LMP correlation. The LMP correlation approach could be used to predict the transient mechanical response of fuel cladding under high temperature conditions.

Larson–Miller Failure Modeling of Aluminum in Fire

“…where T ss is the steady-state temperature and t fss is the time taken for the material to fail after the temperature reaches T ss [14] The first term on the right-hand side of Eq. [10] represents the unsteady-state thermal condition, while the second term represents the isothermal condition (steady-state temperature).…”