PNNL

Abstract

In this study, I2(g) reactions with 11 metal wires (i.e., Al, Ag, Cu, In, Mo, Nb, Ni, Pd, Pt, Sn, Ta) were evaluated at three temperatures (i.e., 100 ± 3°C, 123 ± 4°C, 139 ± 5°C) with exposure times of 24 hours at each temperature. Over these temperatures, some of the metals showed increased mass gain with higher temperatures (i.e., In, Ag, Cu), Sn showed decreased iodine capture at increased temperatures, and most metals (i.e., Mo, Nb, Ni, Pd, Pt, and Ta) showed little to no mass gain at all temperatures. Silver mordenite (AgZ) was used as a standard during these studies and showed a consistent mass gain (m%I) of 10.6% ? 12.8% over this temperature range. The values of mass of iodine captured per mass of starting metal (g g-1) ranged widely across the study with the highest values achieved for (in descending order) Sn-T100C (4.37), In-T139C (3.34), Sn-T123C (1.98), In-T123C (1.57), Ag-T139C (1.19), In-T100C (0.97), and Cu-T139C (0.71). In some cases, the metal-iodide complex was not stable at the experimental temperature and it was clear some volatility had occurred during the experiment based on discoloration in the vials. These results show that some metals can have extensive reactions with I2(g) without showing metal-iodide preferences over metal-oxide formation based on thermodynamic predictions. It is possible that materials such as these could be implemented near nuclear facilities to getter I2(g) in the event of a nuclear accident.