# US 2022/0044830 A1 · Coated fuel pellets, methods of making and using same

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- Number: US 2022/0044830 A1
- Document ID: US20220044830A1
- Status: Published application
- Kind: A1
- Application number: 16/986,180
- Filed: 2020-08-05
- Published: 2022-02-10
- Earliest claimed: 2020-08-05
- Assignees: Uchicago Argonne, LLC
- Applicants: Uchicago Argonne, LLC
- Inventors: Abdellatif M. Yacout; Sumit Bhattacharya
- Web page: https://patentgrep.com/patent/US20220044830A1

## CPC

- G21C 3/626: {Coated fuel particles}
- C23C 16/045: {Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates}
- C23C 16/34: Nitrides {(C23C16/303 takes precedence)}
- C23C 16/45525: {Atomic layer deposition [ALD]}
- C23C 16/45553: {characterized by the use of precursors specially adapted for ALD}
- C23C 16/45555: {applied in non-semiconductor technology}
- C23C 16/56: After-treatment
- C23C 28/00: Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C 28/04: only coatings of inorganic non-metallic material
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- C23C 28/34: {including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates}
- G21C 3/045: {Pellets}
- G21C 3/047: {Pellet-clad interaction}
- G21C 3/20: with coating on fuel or on inside of casing; with non-active interlayer between casing and active material {with multiple casings or multiple active layers}
- G21C 3/58: Solid reactor fuel {Pellets made of fissile material}
- G21C 3/62: Ceramic fuel
- G21C 21/02: Manufacture of fuel elements or breeder elements contained in non-active casings
- Y02E 30/30: Nuclear fission reactors
- Y10T 428/2991: Coated
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Fuel pellets can include a fission material powder, a protective layer coated on the fission material powder, and an oxidation diffusion barrier coated on the protective layer, with the protective layer and oxidation diffusion barrier being formed through ALD to achieve infiltration of the coatings within the fuel pellets.

## Claims

### Claim 1

A method of preparing a coated fuel pellet via atomic layer deposition (ALD), the method comprising:
providing a green compact formed from a fission material powder in an atomic layer deposition chamber and pulling a vacuum within the chamber at a rate of about 1 Torr/min to about 10 Torr/min;
depositing a protective coating on the green compact using atomic layer deposition such that the protective coating infiltrates into the green compact, to provide a protective-coated green compact, wherein the protective coating comprises a metal nitride, molybdenum, or a combination thereof;
depositing an oxide-based coating on the protective-coated green compact using atomic layer deposition such that the oxide-based coating infiltrates into the protective-coated green compact, thereby providing an oxidation diffusion barrier; and,
sintering the protective-coated green compact with the oxygen diffusion barrier, thereby providing the coated fuel pellet.

### Claim 2 (depends on 1)

The method of claim 1, wherein the fission material powder comprises uranium silicide (U3Si2), uranium nitride (UN), uranium carbide (UC), or a combination thereof.

### Claim at position 3

-5. (canceled)

### Claim 6 (depends on 1)

The method of claim 1, wherein the metal nitride is selected from the group consisting of aluminum nitride (AlN), silicon nitride (Si3N4), titanium nitride (TiN), zirconium nitride (ZrN), or any combination thereof.

### Claim 7

(canceled)

### Claim 8 (depends on 1)

The method of claim 1, wherein the protective coating comprises molybdenum.

### Claim 9 (depends on 1)

The method of claim 1, wherein the oxide-based coating is selected from the group consisting of aluminum oxide (Al2O3), zirconium oxide (ZrO2), zirconium (IV) silicate (ZrSiO4), silicon dioxide (SiO2), yttrium oxide (Y2O3), chromium (II) oxide (CrO), chromium (III) oxide (Cr2O3), chromium (IV) oxide (CrO2), chromium (VI) oxide (CrO3), and any combination thereof.

### Claim 10

(canceled)

### Claim 11 (depends on 1)

The method of claim 1, wherein the protective coating and/or the oxide-based coating is deposited at a temperature of about 200° C. to about 250° C.

### Claim 12

(canceled)

### Claim 13 (depends on 1)

The method of claim 1, wherein depositing the protective coating comprises alternately depositing two or more protective coating precursors on the green compact, wherein the two or more protective coating precursors are independently selected from the group consisting of tetrakis(dimethylamido)zirconium(IV) (TDMAZ), trimethylaluminum, tris(dimethylamido)aluminum(III), tetrakis(diethylamido)titanium(IV) (TDEAT), tris(dimethylamino) silane (TDMSi), disilane, molybdenum hexafluoride, ammonia, hydrazine, and any combination thereof.

### Claim 14

(canceled)

### Claim 15

(canceled)

### Claim 16 (depends on 13)

The method of claim 13, wherein depositing each of the protective coating precursors has a pulse time of about 1 second to about 10 seconds and a purge time of at least about 60 seconds.

### Claim at position 15

-19. (canceled)

### Claim 20 (depends on 1)

The method of claim 1, wherein depositing the oxide-based coating comprises alternately depositing two or more oxide-based coating precursors on the protective-coated green compact, wherein the two or more oxide-based coating precursors are independently selected from the group consisting of tetrakis(dimethylamido)zirconium(IV) (TDMAZ), bis(methyl-η5-cyclopentadienyl)methoxymethylzirconium (ZRCMMM), trimethylaluminum, tris(dimethylamido)aluminum(III), tetrakis(dimethylamido)titanium(IV) (TDMAT), tetrakis(diethylamido)titanium(IV) (TDEAT), titanium tetrachloride, tris(dimethylamino)silane (TDMAS), hexachlorodisilane, water, hydrogen peroxide, ozone, tris(cyclopentadienyl)yttrium (Cp3Y), tris(methylcyclopentadienyl)yttrium ((CpCH3)3Y), bis(cyclopentadienyl)chromium(II), bis(pentamethylcyclopentadienyl)chromium(II), chromyl chloride, methanol, and any combination thereof.

### Claim 21

(canceled)

### Claim 22

(canceled)

### Claim 23 (depends on 20)

The method of claim 20, wherein depositing each of the oxide-based coating precursors has a pulse time of about 1 second to about 10 seconds and a purge time of at least about 60 seconds.

### Claim at position 20

-28. (canceled)

### Claim 29 (depends on 1)

The method of claim 1, wherein the coated fuel pellet comprises the protective coating and the oxide-based coating in an amount of about 2 wt % to about 10 wt %, based on the total weight of the coated fuel pellet.

### Claim 30 (depends on 1)

The method of claim 1, wherein the coated fuel pellet has an onset temperature for steam oxidation that is at least about 100° C. higher than an uncoated fuel pellet.

### Claim 31

(canceled)

### Claim 32

A fuel pellet, comprising:
a fission material powder;
a protective layer coated on the fission material powder; and,
an oxidation diffusion barrier coated on the protective layer.

### Claim 33 (depends on 32)

The fuel pellet of claim 32, wherein the fission material powder comprises uranium nitride (UN), uranium silicide (U3Si2), uranium carbide (UC), or a combination thereof.

### Claim at position 26

-36. (canceled)

### Claim 37 (depends on 32)

The fuel pellet of claim 32, wherein the protective coating is selected from the group consisting of aluminum nitride (AlN), silicon nitride (Si3N4), titanium nitride (TiN), zirconium nitride (ZrN), molybdenum (Mo), and any combination thereof.

### Claim 38

(canceled)

### Claim 39 (depends on 32)

The fuel pellet of claim 32, wherein the protective coating is free of magnesium nitride.

### Claim 40 (depends on 32)

The fuel pellet of claim 32, wherein the oxidation diffusion barrier comprises aluminum oxide (Al2O3), zirconium oxide (ZrO2), zirconium (IV) silicate (ZrSiO4), silicon dioxide (SiO2), yttrium oxide (Y2O3), chromium (II) oxide (CrO), chromium (III) oxide (Cr2O3), chromium (IV) oxide (CrO2), chromium (VI) oxide (CrO3), and any combination thereof.

### Claim 41

(canceled)

### Claim 42 (depends on 32)

The fuel pellet of claim 32, wherein the protective layer coated on the fission material powder has thickness of about 20 nm to about 50 nm.

### Claim 43 (depends on 32)

The fuel pellet of claim 32, wherein the protective layer and the oxidation diffusion barrier have a total thickness of at least about 200 nm.

### Claim at position 34

-47. (canceled)

### Claim 48 (depends on 32)

A light-water reactor (LWR) comprising the fuel pellet of claim 32.