Retention of 137Cs and 90Sr by mineral sorbents surrounding vitrified nuclear waste

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Authors:Lyon, K. E.; Patterson, R. J.
Author Affiliations:Primary:
91 Clovelly Ave., Toronto, ON, Canada
Other:
Environ. Can., Natl. Hydrol. Res. Inst., Canada
Source:NHRI Paper, Vol.27, p.19. Publisher: National Hydrology Research Institute, Inland Waters Directorate, Ottawa, ON, Canada. ISSN: 0713-2816. ISBN: 0-662-14693-X
Publication Date:1985
Note:In English with French summary. 45 refs.IWD Scientific Series No. 148
Summary:Twenty-five 14-cm diameter hemispheres of vitrified nuclear waste (glass blocks) were buried in a shallow sand aquifer in the lower Perch Lake basin, Chalk River Nuclear Laboratories, Ontario, Canada. Almost all leaching of the glass blocks occurred during the first 18 months of emplacement, and consequently the burial experiment approximated a single-injection source of 137Cs and 90Sr. After about 11 years, most of the 90Sr that was released had been advected and dispersed from the site, whereas the bulk of the 137Cs had travelled no more than 0.3 m from the blocks. Three piezometers were installed and five cores of sediment were collected at the glass block site in 1978. Mineralogically pure segregates of sand grains were prepared by hand and characterized using binocular, petrographic and scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. A technique also was developed to measure very low levels of 137Cs and 90Sr by counting small (10-100 mg) sediment samples directly with a thin window, flow proportional counter. Results show that sand-sized grains of altered biotite (biotite-vermiculite), biotite, muscovite, hornblende and sericitized feldspar are able to retain 137Cs over a period of 18 years, and that grains of biotite-vermiculite, biotite and hematite-bearing feldspar (largely microcline) can retain low levels of 90Sr over the same period of time. The amounts of 137Cs and 90Sr sorbed by the mineral grains ranged from undetectable levels to approximately 380 and 35 becquerels/gram sediment, respectively. The complete series of mineral segregates can be ranked on a weight basis according to the amounts of retained 137Cs and 90Sr. Modified journal abstract.
Subjects:Alkali metals; Alkaline earth metals; Aquifers; Cesium; Cores; Cs-137; Engineering geology; Ground water; Isotopes; Metals; Minerals; Radioactive isotopes; Radioactive waste; Sample preparation; Sediments; Sr-90; Strontium; Surveys; Waste disposal; Water quality; Canada; Eastern Canada; Ontario; Perch Lake basin; Sorbents
Record ID:1986067916
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute.
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