Mixed Stream Test Rig (MISTER) Startup Report

This report describes the work accomplished to date to design, procure, assemble, authorize, and startup the Mixed Stream Test Rig (MISTER) at the Idaho National Laboratory (INL). It describes the reasons for establishing this capability, physical configuration of the test equipment, operations methodology, initial success, and plans for completing the initial 1,000 hour test of high temperature specimens. MISTER was assembled in FY 2010 to test high temperature materials within environments of gas compositions that are expected in the high temperature steam electrolysis (HTSE) hydrogen production process. The test system is designed to provide realistic environments for studying the effects of high-temperature gas mixtures upon material samples. It does this with two separate gas streams of variable composition within a single furnace, exposing material samples to the gases at temperatures up to 1100 C. Understanding the resulting material corrosion rates will help inform materials selection and qualification to ensure successful future performance. The initial test focuses on potential alloys for use in the oxygen and hydrogen streams from the HTSE process, although MISTER is also capable of controlling mixtures of CO, CO2, N2, and other gases. Table S-1 provides a list of commercial alloys selected for the first MISTER test, which was initiated at 800 C to reflect the gas temperatures at the HTSE anode and cathode. The hydrogen stream contains 33% moisture and the oxygen stream contains 50% nitrogen , which reflects expected HTSE gas conditions. The three Haynes alloys in Table S-1 were selected because of superior performance in previous INL HTSE testing. The final alloy was chosen because it has been selected for use in several NGNP heat transport system components. Alloy 800H is already listed in the ASME nuclear section (ASME Code Section III Division 1), although the maximum use temperature and time need to be increased to support use at the conditions expected for nuclear-integrated operations (including hydrogen production).