Evaluating strength and ductility of irradiated zircaloy. Quarterly progress report for October--December 1975

The characterization of H. B. Robinson Power Plant fuel rods was continued with the completion of profilometry and plenum-gas measurements on the last three of these rods. Neutron dosimetry data were obtained from which the fast-neutron fluence exposure ranging from 3.8 to 4.4 x 1021 n/cm2 (greater than 1 MeV) was calculated for the fuel rods. The effect of short-term anneals (0 to 30 s) at 10000F following a 100F/s transient to the annealing temperature was investigated by means of hardness measurements. While hardness decreased as a result of heating to 10000F, the effect of time at temperature on hardness was minimal. Similar anneals following a more rapid transient are planned. Tensile tests were performed on as-irradiated tubing at temperatures ranging from room temperature to 8000F. The effect of strain rate on tensile properties was evaluated at 7000F with strain rates ranging 0.0025 to 2.5/min. Strength values increased significantly at the highest strain rate. Equipment and specimens are being prepared for the performance of burst, bend, expanding-mandrel, and transient-burst tests