# US 2014/0197557 A1 · Method for preparing a porous nuclear fuel

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- Number: US 2014/0197557 A1
- Document ID: US20140197557A1
- Status: Published application
- Kind: A1
- Application number: 14/239,614
- Filed: 2012-08-21
- Published: 2014-07-17
- Earliest claimed: 2011-08-22
- Assignees: Commissariat A L'energie Atomique Et Aux Ene Alt
- Inventors: Sebastien Picart; Elodie Remy; Thibaud Delahaye
- Web page: https://patentgrep.com/patent/US20140197557A1

## CPC

- G21C 3/62: Ceramic fuel
- G21C 3/623: {Oxide fuels}
- Y02E 30/30: Nuclear fission reactors
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method for producing a porous fuel including uranium, optionally plutonium, and optionally at least one minor actinide, the method including: a) compacting a mixture including a first type of agglomerate including uranium oxide in a form of uranium dioxide UO2, optionally plutonium oxide, and optionally at least one minor actinide oxide, and a second type of agglomerate including uranium oxide in a form of triuranium octaoxide U3O8, optionally plutonium oxide, and optionally at least one minor actinide oxide; b) reducing the compacted mixture in a reducing medium, to reduce all or part of the triuranium octaoxide U3O8 into uranium dioxide UO2, the second type of agglomerate being prepared prior to the compacting by a series of specific operations.

## Claims

### Claim at position 1

1-11. (canceled)

### Claim 12

A method for producing a porous fuel including uranium, optionally plutonium, and optionally at least one minor actinide, the method comprising:
a) compacting a mixture including a first type of agglomerate including uranium oxide in a form of uranium dioxide UO2, optionally plutonium oxide, and optionally at least one minor actinide oxide, and a second type of agglomerate including uranium oxide in a form of triuranium octaoxide U3O8, optionally plutonium oxide, and optionally at least one minor actinide oxide;
b) reducing the compacted mixture in a reducing medium, to reduce all or part of the triuranium octaoxide U3O8 into uranium dioxide UO2;
wherein the agglomerates of the second type are prepared prior to the compacting by operations including:
i) an operation of preparing a charge solution including a nitric solution including uranium in a form of a complex of hydroxylated uranyl nitrate and optionally plutonium and/or at least one minor actinide in a form of plutonium nitrate and/or nitrate of at least one minor actinide;
ii) an operation of passing the solution through a cation exchange resin including carboxylic groups, the resin being constituted of beads of cation exchange resin including carboxylic groups, such that the uranium in uranyl form and optionally plutonium and/or at least one minor actinide in cationic form remain fixed to the resin;
iii) an operation of heat treatment of the resin in a medium including oxygen, thereby obtaining the agglomerates of the second type.

### Claim 13 (depends on 12)

A method for producing a porous fuel according to claim 12,
wherein the agglomerates of the first type have a spherical shape.

### Claim 14 (depends on 12)

A method for producing a fuel according to claim 12, wherein the agglomerates of the second type have a spherical shape.

### Claim 15 (depends on 12)

A method for producing a fuel according to claim 12, wherein the agglomerates of the first type are prepared prior to the compacting.

### Claim 16 (depends on 15)

A method for preparing a fuel according to claim 15, wherein the agglomerates of the first type are prepared by reduction of agglomerate including uranium oxide in a form of triuranium octaoxide U3O8 optionally in association with plutonium oxide and optionally one or more oxides of at least one minor actinide.

### Claim 17 (depends on 16)

A method according to claim 16, wherein the agglomerates including uranium oxide in a form of triuranium octaoxide U3O8 optionally in association with plutonium oxide and one or more oxides of at least one minor actinide are derived from operations i), ii), and iii).

### Claim 18 (depends on 12)

A method according to claim 12, wherein the agglomerates of the second type are in a form of spheres having an average diameter above 50 μm, or ranging from 100 to 1200 μm.

### Claim 19 (depends on 12)

A method according to claim 12, further comprising dry mixing the agglomerates of the first type and of the second type, the dry mixing being implemented before the compacting.

### Claim 20 (depends on 12)

A method according to claim 12, wherein the reduction b) is carried out by passage of a current comprising a reducing gas at a temperature ranging from 600 to 1000° C. for a duration ranging from 1 to 12 hours.

### Claim 21 (depends on 12)

A method according to claim 12, further comprising, after b), a sintering.

### Claim 22 (depends on 21)

A method according to claim 21, wherein the sintering is carried out by heating at a temperature ranging from 1000 to 1900° C. for a duration ranging from 1 to 12 hours.