Glass Melter Replacement and Melter Technology Development in the Tokai Vitrification Facility

Japan Nuclear Cycle Development Institute (JNC) has the vitrification facility (Tokai Vitrification Facility: TVF) at the Tokai Reprocessing Plant (TRP) site (Fig. 1). In the TVF, highly radioactive liquid waste from the main process of the TRP is vitrified into glass matrix. On March of 2002, the damage on one electrode of the 1st melter occurred, so JNC decided to exchange the melter to the new one in two years. The design of the second melter to be replaced is modified to have more effective discharge ability of the platinum group metal compounds which are suspended in the molten glass matrix. The exchange project has four main steps: (1) fabrication of the new melter, (2) removal the failed melter, (3) installation of the new melter in the TVF and (4) dismantling the failed melter. As of April 2004, fabrication of the new melter and its cold operation test have been completed and the in-cell remote installation has been initiated. The installation will be finished until the end of August 2004 and the TVF operation will restart on October. For dismantling of the melter, JNC planned to cut structural materials by the YAG laser system and has progressed the device design and fabrication. The melter dismantling will be started in 2005 and it also includes detail investigation of the failed electrode. In the TVF, JNC have started other new activities for development of future melter technologies such as (1) design study of advanced melter, which has less environmental burden (2) glass volume reduction.