X-ray absorption spectroscopy of actinide speciation in solid solutions

It is widely recognized that the behavior of actinides in the environment is dictated by their speciation, or chemical form. It is therefore imperative to have a clear understanding of a waste form or environmental contaminant in order to effectively assess and treat the affected area. Current methodology utilizes the distribution coefficient (Kd), a rough measure of contaminant mobility in environmental systems, however neither the empirical nor theoretical determination of Kd is well defined. Although we understand the limitation of the Kd parameter, the reality is that the Kd is often the only parameter used in environmental fate and transport models to account for the mobile fraction of contaminate in predicting total risk. A fresh approach to the problem incorporating speciation that can be applied to a wide range of conditions is required. X-ray absorption spectroscopy (XAS), a nondestructive technique that is ideal for determining the molecular composition of materials in dilute quantities in solution and solid forms, was used to determine the speciation of actinides in various solid nuclear materials including nuclear fuel, environmental contaminants, and advanced nuclear materials. This data could then be applied to individual systems to evaluate the environmental impact of the material via empirical or theoretical modeling. The fuels examined include Th₃UO₈, UC and a mixture of UC and US. In addition, an actual contaminant, metallic uranium-bearing samples recovered from the environment several decades after their accidental formation, was evaluated.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Nuclear Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Curran, Virginia, 1977-

Advisor dc:contributor.advisor

• Kenneth R. Czerwinski.

• Nuclear Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/17642

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/17642