| Popis: |
Current plans for disposal of the low-level fraction of selected double-shell tank (DST) wastes at Hanford, Washington include grouting. Grout disposal in this context is the process of mixing low-level liquid waste with cementitious powders. and pumping the resultant slurry to near-surface, underground concrete vaults. Once the slurry is in the vaults. the hydration reactions that occur result in the formation of a highly impermeable solid product that binds and encapsulates the radioactive and hazardous constituents. Westinghouse Hanford Company (WHC) operates the Grout Treatment Facility (GTF) for the US Department of Energy (DOE). Pacific Northwest Laboratory(a) (PNL) provides support to the Grout Disposal Program through laboratory support activities, radioactive grout leach testing. performance assessments, and pilot-scale tests. A pilot-scale test was conducted in November 1988 using a simulated Double-Shell Slurry Feed (DSSF) waste. The main objective of the pilot-scale test was to demonstrate the processability of a DSSF grout formulation that was developed using laboratory equipment and to provide information on scale-up. The dry blend used in this test included 47 wt% class F fly ash, 47 wt% blast furnace slag, and 6 wt% type I/II portland cement. The dry blend was mixed with the simulated waste at a ratiomore » of 9 lb/gal and pumped to a 2800-gal, insulated tank at about 10.4 gpm. Samples of simulated DSSF waste. dry blend, grout slurry, and cured grout were obtained during and after the pilot-scale test for testing and product characterization. Major conclusions of these activities are included.« less |
