CORROSION OF URANIUM ALLOYS IN HIGH-TEMPERATURE WATER

Abstract

In the search for a corrosion-resistant high-uraniumcontent alloy for use as core material in high-temperature-water-moderated reactors, the corrosion of binary and ternary U alloys was studied in water at 500 and 600 deg F. Alloys contaiiifng less than 40 wt,% Zr additions completely oxidized upon short exposure at 600 deg F, whereas 50 plus wt.% alloys exhibited relatively low corrosion rates. Alloys were sensitive to heat treatment and were most resistant in the quenched condition. The corrosion rates of Zr alloys were linear to slightly accelerated with respect to time. Alloys containing 40, 50, and 60 wt.% Zr were resistant to water at 500 deg F. Molybdenum additions (arc-melted alloys) in the range of 10 to 15 wt.% improved the resistance of U to 600 deg F water but did not result in corrosion-resistant alloys, probably because of inhomogeneity of the alloys studied. The addition of Mo, Nb,Th, Sn, and Ti to uranium--20 wt.% zirconium resulted in several promising alloys: uranium--20 zirconium--5 molybdenum and uranium--20 zirconium-10 niobium. Additions of up to 5 wt,% Mo did not improve the resistance of 40 and 50% Zr alloys to 600 deg F water. A uranium--30 zirconium--5.6 tantalum alloy also exhibited promising resistance tomore » 600 deg F water. Other additions (2 and 5 at.%) which did not improve the resistance of uranium--30 wt.% zirconium were: Sb, Bi, Cc, Cr, Co, Fe, Pb, Ni, Nb, Si, Th, Ti, and W. (auth)« less