Oxidation/Corrosion of Nb-1 Zr and PWC-11 in Lithium for Space Reactor Applications

Abstract

The materials Nb-1 Zr and Nb-1 Zr-0.1 C (PWC-11) are candidate structural materials for compact lithium-cooled reactor systems for space applications. Because the mechanical and corrosion properties of niobium alloys can be significantly altered by oxygen, components must be protected from reactions with oxygen during ground testing. The effect of simultaneous oxidation/corrosion behavior in lithium was determined under several conditions, as well as the conditions under which a thin molybdenum coating was effective in preventing oxidation/corrosion. The effects of oxygen can be mitigated by its reaction with zirconium, and studies were also conducted to evaluate time-temperature relationships for this reaction.