RECENT STATUS ON HIGH-TEMPERATURE SUPERCONDUCTING BI2SR2CACU2O8- 1-90METER LENGTH J(C)S AND 3 METER DIAMETER RING FURNACE DESIGN(X WIRE DEVELOPMENT AT NYSIS )

The status of long length, Bi2Sr2CaCu2O8+x (Bi-2212) wire development at the New York State Institute on Superconductivity (NYSIS) is review ed and updated. Transport J(c)s (4.2K, 0 T) of Bi-2212/Ag oxide powder -in-tube single-filamentary tapes have reached 70,000-80,000, 50,000-6 0,000, and 30,000-40,000 A/cm(2) for 1, 4-15, and 40-90 meter length t apes, respectively. The decrease in J as the tape length was increased from 15 to 90 meters was attributed to the (measured) sensitivity of J to temperature nonuniformities (+/-3 degrees C) in the box-type furn ace used for annealing. To reduce this problem, a ring-type high-tempe rature furnace (similar to 3 meter diameter) was designed and construc ted which provides a large-volume (similar to 13(W) x 10(h) x 1000(1) cm) processing zone with expected excellent temperature uniformity (+/ -0.5 degrees C). The advantages of the ring-type furnace for processin g of kilometer-length conductors are described.