The electrode and insulating walls are described and the appropriate parameters that are used to predict the performance of the module are given. The U-02 facility is described and the operational parameters are given for each phase of the test. Failure was not due to the electrode materials, however, but due to lead-out melting caused by joule heating in the platinum wires. Five pairs failed early in the life test and the sixth pair failed in the last several hours. These were the pairs which were designated to carry maximum or near maximum current density. All except six electrode pairs performed satisfactorily during the entire test. (4) Shut-down of the channel over a specific cool down period - 9 hours. (2) Electrical tests at operating temperature to investigate electro-physical characteristics of the channel and electrodes - 6 hours. No seed (K/sub 2/C0/sub 3/) introduction - 18 hours. There were four main phases in the test schedule: (1) start-up of the channel over a specific heating period. Each of the five electrode materials had more » four different current densities established between the anode and cathode during the experiment which lasted a total of 127 hours. The electrode modules were constructed by Westinghouse Research and Development Laboratory. The test procedure followed closely a predetermined work plan designed to test five different zirconia based materials and the cathode and anode electrode wall modules under MHD operating conditions. electrode materials was carried out in Moscow between September 25 and Octoin the Soviet U-02 MHD facility. Pre-test measurements were made to determine: thermal diffusivity, thermal expansion, chemical composition, microstructure, electrical conductivity, phase composition, closed and open porosity and pore size distribution. Extensive pre- and post-test materials characterizations were made to determine the effect of the MHD environment on the electrodes and insulators. (4) Shut-down of the channel over a specific cool down period. (3) Operating life test of electrodes at various assigned current densities. (2) Electrophysical tests of the electrodes at operating temperature with seed and magnetic field. There were four main phases in the test schedule: (1) Start-up of the channel over a specific heating period. The opposing electrodes were separately loaded to various assigned current densities during the experiment which lasted a total of 131 hours with 75 hours under MHD power operational conditions.

The cathode and anode wall had six modules apiece. Opposing electrodes on the anode and cathode were of the same material. The materials were arranged into modules more » of five electrodes apiece each with its own heat sink. The materials which were selected were Graded CeO/sub 2//ZrO/sub 2/ 50 CeO/sub 2/-50 ZrO/sub 2/ 75 MgAl/sub 2/O/sub 4/-25 Fe/sub 3/O/sub 4/ 75 FeAl/sub 2/O/sub 4/-25 Fe/sub 3/O/sub 4/ and 95 LaCrO/sub 3/-5 Mg. The test procedure followed closely a predetermined work plan designed to test five different electrode materials, different leadouts and attachments, and the cathode and anode electrode walls under MHD operating conditions.

electrode materials was carried out in Moscow between September 21 and Septemin the Soviet U-02 MHD Facility. The second (Phase II) joint U.S.-U.S.S.R.

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