Vanadium alloy development for sodium-cooled reactors

Abstract

Because of favorable nuclear properties and high-temperature mechanical properties, vanadium alloys are attractive as possible fuel cladding materials for sodium-cooled fast-breeder reactors, the only disadvantage being vanadium's affinity for oxygen that leads to the formation of non-adherent oxides when vanadium or vanadium alloys are exposed to sodium containing more than several parts per million of oxygen. Over the years investigators have tested numerous binary and several ternary alloys, and all have exhibited the above described behavior. It is now generally accepted that sodium contacting vanadium alloy fuel cladding must be trapped to avoid scale formation. Hence, it is possible to use vanadium alloy cladding if it can be protected from serious damage during any oxygen excursion. In this paper we have examined the oxidation problem and suggested several possibilities for protecting the cladding during an oxygen excursion.