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Comparison of 200 Liter and 40 Milliliter Leach Tests*

Published online by Cambridge University Press:  21 February 2011

J. H. Westsik JR.,
Affiliation:
Pacific Northwest Laboratory, P.O. Box 999, Richland, Washington 99352
C. O. Harvey
Affiliation:
Pacific Northwest Laboratory, P.O. Box 999, Richland, Washington 99352
F. P. Roberts
Affiliation:
Pacific Northwest Laboratory, P.O. Box 999, Richland, Washington 99352
W. A. Ross
Affiliation:
Pacific Northwest Laboratory, P.O. Box 999, Richland, Washington 99352
R. E. Thornhill
Affiliation:
Pacific Northwest Laboratory, P.O. Box 999, Richland, Washington 99352
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Abstract

During the past year we have conducted a modified MCC-1 leach test on a 145 kg block of a cast cement waste form. The leach vessel was a 200 liter Teflon®-lined drum and contained 97.5 liters of deionized water. The results of this large-scale leach test were compared with the results of standard MCC-1 tests (40 ml) on smaller samples of the same waste form. The ratio of leachate volumes between the large and small scale tests was 2500 and the ratio of sample masses was 150,000. The cast cement samples for both tests contained plutonium-doped incinerator ash.

The leachates from these tests were analyzed for both plutonium and the matrix elements. Evaluation of plutonium plateout in the large-scale test indicated that the majority of the plutonium leached from the samples deposits onto vessel walls and little (<3 × 10−12M) remains in solution. Comparison of elemental concentrations in the leachates indicates some differences up to 5X in the concentration in the large- and small-scale tests. The differences are attributed to differences in the solubilities of Ca, Si, and Fe at pH ˜11.5 and at pH ˜12.5. The higher pH observed for the large-scale test is a result of the larger quantities of sodium in the large block of cement.

Type
Research Article
Copyright
Copyright © Materials Research Society 1983

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Footnotes

**

Operated for the U.S. Department of Energy by Battelle Memorial Institute.

*

Work performed for the U.S. Department of Energy under Contract DE–AC06–76RLO 1830.

References

REFERENCES

1. Materials Characterization Center, “MCC-1P Static Leach Tests Methods,” in Nuclear Waste Materials Handbook, DOE/TIC-11400 (Pacific Northwest Laboratory, Richland, Washington 1981)Google Scholar
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