Melting of qualified HLW glass-the process and product control of the Karlsruhe vitrification facility (VEK)

Vitrification of about 70 m3 of high-level waste (HLW) solution with a total activity of 7.7E17 Bq is a major step within the decommissioning program of the former Karlsruhe pilot reprocessing plant WAK. The immobilization will be carried out in a new vitrification plant designated VEK. The technology applied is based on a liquid-fed ceramic melter developed by Forschungszentrum Karlsruhe (FZK). Licensing of the waste product requires the qualification of the VEK process for production of glass canisters the specifications of which have to be in accordance with a set of 16 specified final disposal-relevant parameters. In support of construction, operation and licensing of VEK and the glass product as well, a nonradioactive prototype vitrification test facility was operated from 1998 to 2000 at the Institut fuer Nukleare Entsorgung (INE) of FZK. Within the scope several long-term test runs it could be demonstrated that the VEK process is suitable to produce qualified canisterized glass. (orig.)