Effects of the accumulated annealing parameter on the corrosion characteristics of new Zr-based alloys for fuel cladding

The effects of the accumulated annealing parameter on the corrosion characteristics in the Nb-containing Zr alloys have been investigated. Static autoclave corrosion test was carried out in 360 .deg. C water, 360 .deg. C 70 ppm LiOH, and 400 .deg. C steam on the two Zr alloys (Zr-0.4Nb-0.8Sn-xFeCrMn, Zr-0.2Nb-1.1Sn-xFeCrMn), which were manufactured to give the three given three different accumulated annealing parameters. The corrosion resistance decreased with increasing the accumulated annealing parameter(ΣA) under the corrosion conditions. The microstructure changes with increasing the accumulating annealing parameter were observed by TEM. The corrosion characteristics with increasing the accumulated annealing parameter was mainly analyzed by observing the matrix microstructure and precipitate. The size of precipitates increased with increasing the accumulated annealing parameter. From the XRD analysis of the oxide, it was revealed that the relative fraction of tetragonal ZrO2 also decreased gradually with increasing the accumulated annealing parameter. Conclusively, it could be thought that the controlling of the precipitates size to be small by the decrease of the accumulated annealing parameter gave rise to improve the corrosion resistance in Nb-containing Zr alloys