Modified ring stretch tensile testing of Zr-1Nb cladding

摘要

In a round robin effort between the US Nuclear Regulatory Commission, Institut de211u001eProtection et de Surete Nucleaire in France, and the Russian Research Centre-211u001eKurchatov Institute, Argonne National Laboratory conducted 16 modified ring 211u001estretch tensile tests on unirradiated samples of Zr-1Nb cladding, which is used 211u001ein Russian VVER reactors. Tests were conducted at two temperatures (25 and 400 C) 211u001eand two strain rates (0.001 and 1 s(sup (minus)1)). At 25 C and 0.001 s(sup 211u001e(minus)1), the yield strength (YS), ultimate tensile strength (UTS), uniform 211u001eelongation (UE), and total elongation (TE) were 201 MPa, 331 MPa, 18.2%, and 211u001e57.6%, respectively. At 400 C and 0.001 s(sup (minus)1), the YS, UTS, UE, and TE 211u001ewere 109 MPa, 185 MPa, 15.4%, and 67.7%, respectively. Finally, at 400 C and 1 211u001es(sup (minus)1), the YS, UTS, UE, and TE were 134 MPa, 189 MPa, 18.9%, and 53.4%, 211u001erespectively. The high strain rate tests at room temperature were not successful. 211u001eTest results proved to be very sensitive to the amount of lubrication used on the 211u001einserts; because of the large contact area between the inserts and specimen, too 211u001elittle lubrication leads to significantly higher strengths and lower elongations 211u001ebeing reported. It is also important to note that only 70 to 80% of the 211u001eelongation takes place in the gauge section, depending on specimen geomeq. The 211u001eappropriate percentage can be estimated from a simple model or can be calculated 211u001efrom finite-element analysis.