Characterization of FTR fuel duct tubes

The mechanical and metallurgical properties of three FTR fuel ducts taken from the Cores 1 and 2 fuel duct production sequence are evaluated. Type 316 stainless steel, double vacuum melted with no scrap additions was used for the Cores 1 and 2 fuel ducts. The ducts were fabricated according to RDT Standard E6-20T. The finished parts were targeted to 20 percent cold work (+- 5 percent) as measured by reduction in area. Reduction was obtained by a series of mandrel draws. At three points in the sequential manufacturing process, a duct was set aside for characterization. These points were the first, second, and seventh manufacturing lots. Chemical analyses of test specimens from the identical lots from which the characterized ducts were taken are given. Specimens were taken for metallographic, tensile, and creep-rupture evaluation at various points along each duct length. This was done in order to compare duct wall properties with those of the load pad, and to compare properties at two different locations in the duct wall