THE FABRICATION OF A VANADIUM-STAINLESS STEEL TEST SECTION FOR MHD TESTING OF INSULATOR COATINGS IN FLOWING LITHIUM

To test the magnetohydrodynamic (MHD) pressure drop reduction performa nce of candidate insulator coatings for the ITER Vanadium/Lithium Bree ding Blanket, a test section comprised of a V-4Cr-4Ti liner inside a s tainless steel pipe was designed and fabricated. Theoretically, the MH D pressure drop reduction benefit resulting from an electrically insul ating coating on a vanadium-lined pipe is identical to the benefit der ived from an insulated pipe fabricated of vanadium alone. A duplex tes t section design consisting of a V alloy liner encased in a SS pressur e boundary provided protection for vanadium from atmospheric contamina tion during operation at high temperature and obviated any potential p roblems with vanadium welding while also minimizing the amount of V al loy material required. From the MHD and insulator coating point of vie w, the test section outer SS wall and inner V alloy liner can be model ed simply as a wall having a sandwich construction. Two 52.3 mm OD x 2 .9 m long V-alloy tubes were fabricated by Century Tubes from 64 mm x 200 mm x 1245 mm extrusions produced by Teledyne Wah Chang. The test s ection's duplex structure was subsequently fabricated at Century Tubes by drawing down a SS pipe (2 inch schedule 10) over one of the 53.2 m m diameter V tubes.