Densification studies of Synroc D for high-level defense waste

Technical Report · Mon Jan 17 04:00:00 EST 1983

OSTI ID:6406364

Hoenig, C; Otto, R; Campbell, J

Small- to medium-scale densification experiments were conducted on Synroc D using graphite dies and metal canisters. Pressures at elevated temperatures were applied both isostatically (HIP) and unidirectionally (HUP). Spray-dried/calcined powders formulated for composite or average sludge compositions exhibited initial packing densities of about 25% theoretical. Final densities were in the range of 95 to 99% theoretical, depending on applied pressure and temperature. In final-stage HUP densification, we have found that porosity varies exponentially with time acording to the well-known expression P + P/sub 0/ exp(-K/sub 0/t). The rate constant (K/sub 0/) has the Arrhenius form K/sub 0/ = Asigma exp(-E/RT) which includes a stress or pressure term. Rate constants are calculated from approximately 20 densification experiments conducted under a wide range of conditions; activation energies in the range of 20 to 35 kcal/mole were calculated for the densification process. HIP densification and leaching results are reported for experiments with a wide range of variables: pressure (3 to 30 ksi), temperature (900 to 1200/sup 0/C), redox calcination method, powder fill density and metal canister material. The results support the conclusion that HUP and HIP densification parameters are very similar and that Synroc-D leaching behavior is essentially independent of density in the range of 90 to 100% theoretical.The densification of Synroc D in a collapsible metal-bellows canister has been simulated by means of modeling calculations. Radial buckling tendencies were also evaluated. Results from large-scale HIP experiments are also reported. Up to 50 kg of Synroc D was densified to greater than 99% theoretical density in a metal-bellows canister 36 cm diameter by 24 cm in height. These data were used as a guide to make recommendations for the full-scale HIP densification of Synroc D using metal-bellows canisters.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6406364
• Report Number(s): UCRL-53392; ON: DE83011564
• Country of Publication: United States
• Language: English

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DATA
DENSITY
EXPERIMENTAL DATA
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