INVESTIGATION OF CORROSION AND HIGH TEMPERATURE OXIDATION OF PROMISING ATF CLADDING MATERIALS IN THE FRAMEWORK OF THE IL TROVATORE PROJECT

摘要

The aim of the IL TROVATORE project is thedevelopment, characterization and testing of potentialmaterials for nuclear fuel rod claddings with enhancedaccident tolerance. One main task of the ongoinginvestigations are testing of the cladding/coolantinteractions under operational as well as accidentconditions. A wide range of materials was already tested:oxides, MAX phases, SiC and iron based alloys. Thepaper gives a rough overview about the results ofautoclave tests simulating operational conditions andsteam oxidation tests at 1200°C covering transient designbasis accident conditions.The results of corrosion tests demonstrates theexcellent performance of protective zirconia layers underoperational conditions. Whereas chromia shows a lowcorrosion rate too, the water corrosion of alumina isproblematic. The reaction rates obtained for Cr_2AlC MAXphase depends strongly on the porosity of the material.Dense material behaves well whereas the corrosion ofporous material is fast. The best performance in the steamoxidation tests at 1200°C shows SiC followed by denseCr2AlC MAX phase, FeCrAl and high entropy alloys.Additional information concerning the reaction rateswere obtained by measuring the hydrogen release. Forseveral materials it could be shown that not onlyprocesses occur resulting in mass gain but simultaneousreactions take place resulting in a mass loss.