SIMS and thermal evolution analysis of oxygen in Zr-1%Nb alloy after high-temperature transitions

The concentration of oxygen in the primary beta-phase of Zr-1%Nb alloy was investigated using SIMS and thermal evolution analysis (TEA). The specimens were as-received or preoxidized in water vapor (425 degrees C/10,7 MPa) to simulate the reactor conditions. Then the specimens were exposed to hot water vapor (0,1 MPa) and high temperatures (950-1200 degrees C) for variable time intervals, which simulated the Loss of Coolant Accident (LOCA). The specimens were quenched in water with ice. Both SIMS and TEA quantitative results were in good agreement and were correlated with the mechanical properties (microhardness, residual ductility), which depend on the oxygen concentration and are important for the safety analyses assessment. The ceiling concentration of oxygen in the beta-phase was established based on the experimental results of SIMS and TEA. Copyright (C) 2010 John Wiley & Sons, Ltd.