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This report describes the derivation of the salt composition from the Veazey salt stream analysis. It also provides an estimate of the proportions of the kitty litter, nitrate salt and neutralizer that was contained in drum 68660. While the actinide content of waste streams was judiciously followed in the 1980s in TA-55, no record of the salt composition could be found. Consequently, a salt waste stream produced from 1992 to 1994 and reported by Gerry Veazey provided the basis for this study. While chemical analysis of the waste stream was highly variable, an average analysis provided input to the Stream Analyzer software to calculate a composition for a concentrated solid nitrate salt and liquid waste stream. The calculation predicted the gas / condensed phase compositions as well as solid salt / saturated liquid compositions. The derived composition provides an estimate of the nitrate feedstream to WIPP for which kinetic measurements can be made. The ratio of salt to Swheat in drum 68660 contents was estimated through an overall mass balance on the parent and sibling drums. The RTR video provided independent confirmation concerning the volume of the mixture. The solid salt layer contains the majority of the salt at amore » ratio with Swheat that potentially could become exothermic.« less

Preferential thermal nitridation was used to form a pin-hole defect free CrN/Cr2N surface on a model Ni–Cr alloy. Excellent corrosion resistance and negligible contact resistance increase was observed over a 4100 h exposure in 80 °C sulfuric acid and when used as a metallic bipolar plate in a 1000 h proton exchange membrane (PEM) fuel cell test.

Thermally (gas) nitrided Nb-30Ti-20W wt % exhibited excellent corrosion resistance and maintained good electrical conductivity in 80°C H 2 SO 4 environments designed to simulate proton exchange membrane (PEM) fuel cell bipolar plate conditions. This result supports proof of principle for thermally nitrided alloys as candidate bipolar plate materials, although such Nb-base alloys are too costly for most PEM fuel cell applications. Investigation of the corrosion resistance of a series of relatively inexpensive, thermally nitrided model Ni-X base alloys designed to form Cr 2 N, CrN, NbN, TiN, or VN surface layers have identified nitrided Ni-Cr base alloys as showing corrosion resistance nearly equal to that of the nitrided Nb-30Ti-20W.

Too many unknowns and insufficient data exist for development of a comprehensive theory for repassivation under controlled flow conditions. From results of the first hypothesis which states that supersaturation of the solution at the anode surface may occur, a constant apparent supersaturation ratio for ferrous sulfate of about 3.5 for 1 M H/sub 2/SO/sub 4/ was calculated at the surface for passivation with tau 0.5, the calculated apparent supersaturation ratio approached the saturation concentration for ferrous sulfate at the electrode surface in acidic solutions. At low current densities (i less than or equal to i/sub s/) where the saturation concentration for ferrous ions at the electrode surface was not obtained, passivation was not observed in acidic solutions. These results suggest that, in the systems studied, repassivation occurs only after achieving saturation of ferrous sulfate at the surface. In the second hypothesis, the ferrous sulfate film was assumed to precipitate at saturation of the solution at the anode surface, and to grow in thickness thereafter until passivation occurred. Experimental results follow the trend predicted by the second hypothesis for short passivation times, but large deviations occurred for t/sub p/ > 0.1 seconds.