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Title: Actinide removal from spent salts

A method for removing actinide contaminants (uranium and thorium) from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents are added to precipitate the thorium as thorium oxide and/or the uranium as either uranium oxide or as a diuranate salt. The precipitated materials are filtered, dried and packaged for disposal as radioactive waste. About 90% of the thorium and/or uranium present is removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration <20% require further clean-up using an ion exchange column, which yields salt solutions that contain less than 0.1 ppm of thorium or uranium.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [3]
  1. (Pleasanton, CA)
  2. (Livermore, CA)
  3. (Danville, CA)
Publication Date:
OSTI Identifier:
874838
Report Number(s):
US 6471922
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Patent
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Country of Publication:
United States
Language:
English
Subject:
actinide; removal; spent; salts; method; removing; actinide; contaminants; uranium; thorium; spent; salt; molten; salt; oxidation; mso; reactor; described; spent; salt; removed; reactor; analyzed; determine; contaminants; carbonate; concentration; salt; dissolved; water; reagents; added; precipitate; thorium; thorium; oxide; andor; uranium; uranium; oxide; diuranate; salt; precipitated; materials; filtered; dried; packaged; disposal; radioactive; waste; 90; thorium; andor; uranium; removed; filtration; filtration; salt; solutions; carbonate; concentration; >20; dried; returned; reactor; re-use; salt; solutions; containing; carbonate; concentration; <20; require; clean-up; exchange; column; yields; salt; solutions; contain; 01; ppm; thorium; uranium; molten salt; radioactive waste; salt solution; salt solution; salt solution /423/588/