Method for the recovery of actinide elements from nuclear reactor waste

Patent · Mon Jan 01 00:00:00 EST 1979

OSTI ID:863392

Horwitz, E Philip ^[1]; Delphin, Walter H ^[2]; Mason, George W ^[3]

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1. Elmhurst, IL
2. Woodridge, IL
3. Clarendon Hills, IL

A process for partitioning and recovering actinide values from acidic waste solutions resulting from reprocessing of irradiated nuclear fuels by adding hydroxylammonium nitrate and hydrazine to the waste solution to adjust the valence of the neptunium and plutonium values in the solution to the +4 oxidation state, thus forming a feed solution and contacting the feed solution with an extractant of dihexoxyethyl phosphoric acid in an organic diluent whereby the actinide values, most of the rare earth values and some fission product values are taken up by the extractant. Separation is achieved by contacting the loaded extractant with two aqueous strip solutions, a nitric acid solution to selectively strip the americium, curium and rare earth values and an oxalate solution of tetramethylammonium hydrogen oxalate and oxalic acid or trimethylammonium hydrogen oxalate to selectively strip the neptunium, plutonium and fission product values. Uranium values remain in the extractant and may be recovered with a phosphoric acid strip. The neptunium and plutonium values are recovered from the oxalate by adding sufficient nitric acid to destroy the complexing ability of the oxalate, forming a second feed, and contacting the second feed with a second extractant of tricaprylmethylammonium nitrate in an inert diluent whereby the neptunium and plutonium values are selectively extracted. The values are recovered from the extractant with formic acid.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4162230
• OSTI ID: 863392
• Country of Publication: United States
• Language: English

Related Subjects

method
recovery
actinide
elements
nuclear
reactor
waste
process
partitioning
recovering
values
acidic
solutions
resulting
reprocessing
irradiated
fuels
adding
hydroxylammonium
nitrate
hydrazine
solution
adjust
valence
neptunium
plutonium
oxidation
forming
feed
contacting
extractant
dihexoxyethyl
phosphoric
acid
organic
diluent
whereby
rare
earth
fission
product
separation
achieved
loaded
aqueous
strip
nitric
selectively
americium
curium
oxalate
tetramethylammonium
hydrogen
oxalic
trimethylammonium
uranium
remain
recovered
sufficient
destroy
complexing
ability
tricaprylmethylammonium
inert
extracted
formic
adding sufficient
plutonium values
oxalic acid
nuclear fuels
actinide values
irradiated nuclear
feed solution
ammonium nitrate
fission product
acid solution
nitric acid
nuclear fuel
nuclear reactor
rare earth
phosphoric acid
waste solutions
waste solution
product values
uranium values
formic acid
reactor waste
solutions resulting
aqueous strip
actinide elements
selectively extract
strip solution
recovering actinide
earth values
hydroxylammonium nitrate
/252/423/976/