The Effect of Axial Stress on the Transient Mechanical Response of 20% Cold-Worked Type 316 Stainless-Steel Cladding

Abstract

To understand the effects of the fuel-cladding mechanical interaction on the failure of 20% cold-worked Type 316 stainless-steel cladding during anticipated nuclear reactor transients, the transient mechanical response of the cladding was investigated using a transient tube burst method at a heating rate of 5.6° C/s and axial-to-hoop-stress ratios in the range of ½ to 2.The failure temperatures were observed to remain essentially constant for the transient tests at axial-to-hoop-stress ratios between ½ and 1, but to decrease with an increase in axial-to-hoop-stress ratios above unity. The uniform diametral strains to failure were observed to decrease monotonically with an increase in axial-to-hoop-stress ratio from ½ to 2, and in general, the uniform axial strains to failure were observed to increase with an increase in axial-to-hoop-stress ratio.The fracture of the cladding during thermal transients was found to be strongly affected by the maximum principal stress but not by the effective stress.