Document Type

Annual Report

Publication Date

2007

First page number:

36

Last page number:

37

Abstract

Argonne National Laboratory has proposed a new extraction procedure to handle TRISO-coated fuels, the Fluoride Extraction Process, or FLEX. The FLEX process is designed to separate the uranium in the fuel from the actinides and most fission products by taking advantage of the unique properties of uranium hexafluoride (UF6). In the FLEX process, the used TRISO fuel is reacted with zirconium fluoride salt, forming UF6 and the fluoride salts of the actinides and fission products. At process temperatures, the UF6 volatizes into a gas, and is released from the molten salt mixture. This leaves behind the actinides and most fission products in a fluoride salt, which is subsequently processed using pyrochemical techniques to recover the actinides and other longlived fission products for transmutation. The UF6 is then cooled, causing it to sublime into solid form, which is then further processed for disposal or reuse.

This research attempts to develop a waste form for disposing of the zirconium fluoride fission product waste stream. Fluorapatite, a naturally-occurring fluorinated calcium phosphate, has been identified as a potential matrix for the entombment of this waste stream. If the efficacy of fluorapatite-based waste-storage can be demonstrated, then new and potentially more efficient options for handling and separating high-level wastes, based on fluoride-salt extraction, will become feasible.

Keywords

Calcium phosphate; Fluorides; Phosphate minerals; Radioactive wastes; Separation (Technology); Zirconium compounds

Controlled Subject

Radioactive wastes--Storage; Separation (Technology); Zirconium compounds

Disciplines

Chemistry | Oil, Gas, and Energy | Physical Chemistry

File Format

pdf

File Size

224 KB

Language

English

Rights

COPYRIGHT UNDETERMINED. For more information about this rights statement, please visit http://rightsstatements.org/vocab/UND/1.0/

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