Effect of Thermal Cycling on the Movement of the alpha Zr/ alpha Zr Hydride Phase Boundary in Cold-Worked Zr-2.5 Wt% Nb Alloy

摘要

A piece of CW Zr-2.5 wt% Nb alloy pressure tube was hydrided at one end in 40 g/L LiOH solution at 573 K (after nickel-plating that end). The result was a solid hydride layer 0.6 mm thick plus approximately 130 ppm hydrogen in the core under the nickel plate. Thermal cycling under conditions similar to those likely to be experienced during a reactor trip did not cause any significant movement of the alpha +hydride/ alpha phase boundary along the tube for up to 2688 cycles from 573 to 523 K. Supercharging of the core was observed in the nickel-plated area. Some conclusions have been drawn concerning the origin of the hydrogen in the nickel-plated area, and the factors controlling the supercharging process. (Atomindex citation 12:575155)