Method for the recovery of actinide elements from nuclear reactor waste
A process is described 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 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.
- Assignee:
- Dept. of Energy
- Patent Number(s):
- US 4162230
- OSTI ID:
- 5356734
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
052001* -- Nuclear Fuels-- Waste Processing
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACTINIDES
ELEMENTS
ENERGY SOURCES
ESTERS
EXTRACTION
FUELS
HIGH-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MATERIALS
METALS
NUCLEAR FUELS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORIC ACID ESTERS
PROCESSING
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE PROCESSING
RADIOACTIVE WASTES
REACTOR MATERIALS
REPROCESSING
SEPARATION PROCESSES
SOLVENT EXTRACTION
SOLVENT PROPERTIES
SPENT FUELS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES