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Alpha-Recoil Damage in Thorianite and Uraninite: Effect on Dissolution and Time-Scale for Spontaneous Annealing of Damage

Published online by Cambridge University Press:  26 February 2011

Yehuda Eyal  and
Robert L. Fleischer
Yehuda Eyal
Affiliation:
Department of Nuclear Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
Robert L. Fleischer
Affiliation:
General Electric Corporate Research and Development, Schenectady, New York 12301, USA
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Abstract

Using natural ThO2 and UO2 in which radiation damage has accumulated over geologic periods, we have measured the relative in dissolution rates bicarbonate-carbonate solutions of the actinide isotopes 238U, 234U, 232Th, 230Th, and 228Th. An enhanced dissolution by a factor of 2 to 7 of the short lived (1.9 yr) 228Th relative to that of its structurally incorporated primary isotope 232Th indicates the presence of severe localized atomic displacement damage created by alpha-recoil atoms. In contrast, the relatively small (<20%) isotopic fractionation between the radiogenic 8.0 × 104 yr- 230Th isotope and 232Th, and between the radiogenic 2.5 × 105 yr- 234U isotope and its primary structurally incorporated isotope 238U, suggests the nearly complete annealing of the alpha-recoil damage during a period of less than 105 yr. An estimate of the mean fading time for the leachable damage is 15,000 yr.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 44: Symposium N – Scientific Basis for Nuclear Waste Management VIII , 1984 , 687
Copyright
Copyright © Materials Research Society 1985

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References

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