Abstracts and Available Papers Presented at the
2003 International RERTR Meeting

An Investigation of the Fabrication Technology for Uranium Foils by Cooling-roll Casting

Ki-Hwan Kim, Seok-Jin Oh, Don-Bae Lee, Byung-Chul Lee,

Chang-Kyu Kim and Dong-Seong Sohn

Korea Atomic Energy Research Institute,
150 Deogjin-dong, Yuseong-gu, Daejeon 305-353, Korea

ABSTRACT

An alternative fabrication method for wide U polycrystalline foils with a fine and uniform microstructure has been investigated using a cooling-roll casting method, in order to produce a fission isotope ⁹⁹Mo, the parent nuclide of 99^mTc.  Uranium lumps were charged and induction-melted in a high-temperature-resistant ceramic nozzle.  The superheated molten U metal was fed through a small orifice onto a rotating cooling-roll on a vertical axis.  The liquid metal was then rapidly solidified with a rotating roll driven by an electric motor in an inert atmosphere.  The rapidly solidified foils were collected in a container. Continuous polycrystalline uranium foils with a thickness range of 100 to 150µm and a width of about 50 mm were fabricated, by adjusting the process parameters of the cooling-roll casting apparatus. The uranium foils had a good roughness on the surface, with a few impurities.  The cooling-rolling casting process produced a uranium foil with a high purity and a high productivity.  The uranium foils had fine and uniform polycrystalline grains below about 10 microns in size with the α-U phase, irrespective of the process parameters.  It is expected to be able to prevent the uranium foils from excessive swelling by the an-isotropic growth behavior during irradiation.