METHOD FOR PREPARING A POWDER COMPRISING ONE OR MORE OXIDES SELECTED FROM URANIUM OXIDE UO2, PLUTONIUM OXIDE PuO2 AND MINOR ACTINIDE OXIDES

Patent metadata

Field	Value
Publication number	US-2025382232-A1
Application number	US-202519238725-A
Country	US
Kind code	A1
Filing date	Jun 16, 2025
Priority date	Jun 17, 2024
Publication date	Dec 18, 2025
Grant date	—

Abstract

A method for preparing a powder including one or more oxides selected from uranium oxide UO 2 , plutonium oxide PuO 2 and minor actinide oxides, the minor actinides being selected from americium, neptunium and curium, including steps of: a) cryogenic granulation of an aqueous solution comprising cations selected from uranium-based cations, plutonium-based cations, and minor actinide-based cations; b) freeze-drying the granules obtained in a); and c) calcining the granules obtained from b). The method can be used to manufacture nuclear fuels or blankets charged with minor actinide(s).

First claim

1 . A method for preparing a powder comprising one or more oxides selected from uranium oxide UO 2 , plutonium oxide PuO 2 and minor actinide oxides, the minor actinides being selected from americium, neptunium and curium, comprising steps of:
a) cryogenic granulation of an aqueous solution comprising cations selected from uranium-based cations, plutonium-based cations, and minor actinide-based cations; b) freeze-drying the granules obtained in a); and c) calcining the granules obtained from b); whereby the powder is obtained.

2 . The method according to claim 1 , wherein the cations present in the aqueous solution subjected to step a) are associated with anions to form salt compounds and/or are associated with organic ligands to form complexes.

3 . The method according to claim 1 , wherein the aqueous solution subjected to step a) is an aqueous nitric acid solution wherein the cations are associated with nitrate ions.

4 . The method according to claim 3 , wherein the aqueous solution subjected to step a) comprises at least one nitrate selected from uranyl nitrate UO 2 (NO 3 ) 2 , plutonium nitrate Pu(NO 3 ) 4 and nitrates M(NO 3 ) x , where M is one of the minor actinides and x is an integer ranging from 3 to 6.

5 . The method according to claim 1 , wherein the aqueous solution subjected to step a) further comprises one or more additives selected from water-soluble organic polymers, nitrogenous organic compounds, and mixtures thereof.

6 . The method according to claim 5 , wherein the additive(s) are present in a quantity such that the dynamic viscosity of the aqueous solution does not exceed 1000 mPa.s for a shear rate of 1500 s −1 .

7 . The method according to claim 6 , wherein the dynamic viscosity of the aqueous solution does not exceed 100 mPa.s.

8 . The method according to claim 5 , wherein the water-soluble organic polymer(s) are selected from a polyvinyl alcohol, a polyethylene glycol, a poly (vinyl butyral) and an acrylic latex.

9 . The method according to claim 5 , wherein the nitrogenous organic compound(s) are selected from amide compounds and amine compounds.

10 . The method according to claim 1 , wherein the aqueous solution subjected to step a) comprises a total concentration of actinide element(s) ranging from 5 g/L to 300 g/L.

11 . The method according to claim 1 , wherein the calcination of the granules is an oxidative or reducing calcination or is a calcination which is successively oxidative and then reducing.

12 . The method according to claim 1 , wherein the powder is a UO 2 powder, a PuO 2 powder or a powder comprising a mixture of UO 2 and PuO 2 .

13 . A method for preparing nuclear fuel pellets, successively comprising steps of:
i) implementing a method according to claim 1 for preparing a powder; ii) compacting the powder obtained in i) in pellet form; and iii) sintering the pellets obtained in ii).

14 . The method for preparing nuclear fuel pellets according to claim 13 , wherein the nuclear fuel is a MOX fuel.

Assignees

• Commissariat Energie Atomique

Inventors

• Ramond Laure
• Bernard-Granger Guillaume
• Doreau Franck
• Pagnoux Cécile
• La Lumia Florian
• Signoret Patrice

Classifications

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21C3/623

  Oxide fuels · CPC title

• C04B35/62655

  Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying · CPC title

• C04B35/6265

  involving reduction or oxidation · CPC title

• C04B35/62625

  Wet mixtures · CPC title