ENVIRONMENTAL DEGRADATION RESISTANCE OF ATF FeCrAl CLADDING TUBE SPECIMENS DURING THE FUEL CYCLE

摘要

The nuclear power industry has been using similarmaterials for the light water reactors fleet for over 60years. Since the loss of coolant accidents at theFukushima Daiichi site in March of 2011, the USDepartment of Energy is working with commercial fuelvendors to develop advanced technology or accidenttolerant fuels (ATF) that would make the current fleet ofreactors safer to operate. General Electric and Oak RidgeNational Laboratory are evaluating the concept of usingiron-chromium-aluminum (FeCrAl) alloys or IronClad ascladding for the current fuel of uranium dioxide pellets.Since these FeCrAl ferritic materials were never used in areactor before, it is important to characterize theirenvironmental resistance behavior in the entire fuel cycle,for example, (a) under normal operation conditions, (b)under accident conditions, and (c) under used fuelbehavior in cooling pool conditions. Current results showthat under normal operation conditions of light waterreactors, the FeCrAl IronClad alloys have mass loss butin general would remain passive by the development of aprotective chromium oxide film on their surface. Underaccident conditions the IronClad FeCrAl alloys wouldresist attack by steam by the development of an aluminafilm on the surface and they resist quenching. Under usedfuel storage conditions, the IronClad ferritic alloysremain passive due to the formation of a chromium oxideon the surface. APMT offered the highest resistance toenvironmental degradation of the three FeCrAl materials.