Energetic Analysis of Experimental Behavior of Molten Sn_xLi_y When Impacted by a Vertical Column of Water

The Sn_xLi_y and Pb_xLi_y, alloys are being considered as liquid breeding materials for fusion reactor applications. Thus, it is important to understand the safety implications associated with inadvertent contact with water used in an indirect cycle. In an effort to study this interaction, experiments have been conducted with these molten alloys when impacted with a vertical 2.4-m-tall column of water at 30 and 60°C. The qualitative behavior of Sn₇₅Li₂₅ was compared under similar conditions with other candidate molten metals, specifically tin, lead, and a lead-lithium alloy, Pb₈₃Li₁₇. Multiple pressure spikes were produced with Sn and Pb, while essentially only one initial pressurization followed by a few strongly damped minor peaks was observed with the different alloys containing lithium. Results with tin-lithium are quite similar to pure tin and lead behavior. Dynamic pressure traces from the physical and chemical reactions are discussed and used to compare the energetics associated with the two different alloys. The pressure traces were used to calculate experimental impulses, which represent the energetics of the reactions. The impulse ratio of the experimental and the theoretical values increased in the tests of alloys containing lithium. (Hydrogen production from lithium-water reactions was quite rapid and copious.) In contrast, hydrogen production with tin-lithium was modest and quite similar to the lead-lithium alloy. It was found that the metal-water interactions of Pb₈₃Li₁₇ and Sn₇₅Li₂₅ are quite similar and have significantly reduced energetics from those of pure lithium and other reactive metals being considered.