High-level waste vitrification product characterization

The Nuclear Waste Vitrification Project (NWVP) was conducted to provide a demonstration of the vitrification of high-level liquid waste (HLLW) from spent fuel discharged from an operating LWR. The scope of NWVP included the design, installation, and operation of a small-scale plant preparing actual HLLW for vitrification, and waste solidification by operation of a previously used 1 tU/day spray calciner in-can melter vitrification system. The HLLW was vitrified in two 20.3-cm-(8-in.-) diameter by 2.44-m-(8-ft-) long canisters. Non-destructive testing of the first canister of high level waste glass has indicated very little in the way of unexpected behavior. The glass appears to be uniform with no large anomaies noted. Non-destructive testing of the second canister is incomplete at this time; however, tests have not indicated any unexpected or unusual results. Further testing by destructive methods (e.g., core drilling for an interior view of the glass within the canister, core sampling for determining density, crystallinity, microscopic homogeneity, mechanical conditions, etc., and leach tests to provide fundamental information about leach kinetics and equilibria, etc.) will yield more specific information on the glass. Until such time as these tests are complete, a full comparison of expected and obtained product cannot be made