On the Application of Rousselier's Damage Model to Predict Fracture Resistance Behavior of Zircaloy Fuel Pin Specimens

Abstract

Abstract It may not be possible to machine standard fracture mechanics specimens from the thin-walled fuel pins as used in the nuclear reactors due to their geometry. In order to overcome this problem, a combined experimental and finite element (FE) analysis procedure has been adopted in this work. Determination of transverse mechanical properties from the ring type of specimens machined from the thin-walled nuclear reactor fuel pins is not also straightforward due to the presence of combined tension as well as bending loading conditions. However, finite element analysis of the whole ring tension setup can be carried out and the material stress-strain property can be determined through an inverse and iterative procedure. In this work, ring tension tests were carried out on un-irradiated Zircaloy-4 clad tube specimens. The specimen and the mandrel both were modeled in order to evaluate the load-displacement behavior of the test. The Rousselier's micro- mechanical model for ductile fracture was applied to simulate the crack growth in these specimens. The micro-mechanical parameters as determined from the ring tension experiment and finite element analysis were later used to simulate the crack propagation in a standard double-edged notched tensile (DENT) specimen. The J-R curve of the DENT specimen has also been compared with that of a cracked Pin-Loading-Tension (PLT) specimen.