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Nucleogenic 36 Cl, 236 U and 239 Pu in uranium ores

Date

2008

Authors

Wilcken, Klaus
Fifield, L. Keith
Barrows, Timothy T.
Tims, Stephen
Gladkis, Laura

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

The nucleogenic isotopes 36Cl, 236U and 239Pu are produced naturally in subsurface environments via neutron capture of thermal and epithermal neutrons. Concentrations are, however, very low and accelerator mass spectrometry (AMS) is required for quantitative measurements. A particular challenge is presented by the measurement of 236U/238U ratios down to the level of 10-13 that is expected from rocks with low uranium concentration. Here, we present the AMS methodology that has been developed at the ANU for measuring 236U/238U ratios at this level. The more established methodologies for 36Cl and 239Pu measurements are also summarised. These capabilities are then used to characterize the 36Cl, 236U and 239Pu concentrations in a range of uranium ores. A simple model of the neutron production and capture processes in subsurface environments has been developed and is presented. It is shown that nucleogenic 36Cl, 236U and 239Pu can be used to determine both thermal and epithermal neutron fluxes in subsurface environments. Potential applications include uranium exploration and monitoring of the environmental impact of uranium mining.

Description

Keywords

236 U, 239 Pu, 36 Cl, AMS, Nucleogenic isotope production, Uranium ore, Isotopes 236U, 239Pu, 36Cl, AMS, Nucleogenic isotope production, Uranium ore

Citation

Source

Nuclear Instruments and Methods in Physics Research: Section B

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1016/j.nimb.2008.06.009

Restricted until

2037-12-31