Mn-doped oxide nuclear fuel

Patent metadata

Field	Value
Publication number	US-10847271-B1
Application number	US-201816101808-A
Country	US
Kind code	B1
Filing date	Aug 13, 2018
Priority date	Aug 11, 2017
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A nuclear fuel includes uranium(IV) oxide (UO 2 ) and manganese (Mn) as a dopant. The Mn dopant may be present in the fuel in an amount up to the solubility limit for Mn under a given set of conditions, for example, about 0.01 wt % to about 1 wt %. The nuclear fuel is substantially free of aluminum (Al). The nuclear fuel exhibits enhanced grain size development during sintering temperatures as low at 1400 K due to an increase in uranium sub-lattice vacancies induced by dissolution of the Mn dopant at interstitial defect sites. The Mn-doped nuclear fuel exhibits improved grain sizes at lower temperatures compared to Cr-, Al-, and undoped UO 2 , and therefore desirably exhibits lower fission gas release and higher plasticity, reducing the chances of fuel rod failure.

First claim

What is claimed is:

1. A nuclear fuel pellet comprising uranium(IV) oxide (UO 2 ) and manganese (Mn) atoms, the Mn atoms being present in the nuclear fuel pellet in an amount of about 0.1 wt % to about 1 wt % based on the total weight of the nuclear fuel pellet; and
the nuclear fuel pellet being substantially free of aluminum (Al).

2. The nuclear fuel pellet of claim 1 , wherein the Mn atoms are derived from a manganese salt having one or more counter anions, the one or more counter anions each comprising an oxide anion, a nitride anion, a stearate anion, a chloride anion, or a hydroxide anion.

3. The nuclear fuel pellet of claim 2 , wherein the Mn atoms are derived from a manganese oxide.

4. The nuclear fuel pellet of claim 3 , wherein the manganese oxide is Mn 2 O 3 .

5. The nuclear fuel pellet of claim 1 , wherein the Mn atoms are present in the nuclear fuel pellet in an amount of about 0.1 wt % to about 0.5 wt % based on the total weight of the nuclear fuel pellet.

6. The nuclear fuel pellet of claim 1 , wherein the Mn atoms have an interstitial concentration of about 0.001 to about 0.5 fractional defects per unit of UO 2 at a sintering temperature above about 1430 K.

7. The nuclear fuel pellet of claim 6 , wherein the Mn atoms have an interstitial concentration of about 0.01 to about 0.1 fractional defects per unit of UO 2 at a sintering temperature above about 1700 K.

8. The nuclear fuel pellet of claim 1 , wherein the nuclear fuel pellet has a grain size enhancement factor over undoped UO 2 of about 1.1 to about 35 times after sintering at about 1700 K to about 3200 K.

9. The nuclear fuel pellet of claim 8 , wherein the nuclear fuel pellet has a grain size enhancement factor over undoped UO 2 of about 1.3 to about 14 times after sintering at about 1700 K to about 2000 K.

10. The nuclear fuel pellet of claim 1 , wherein the nuclear fuel pellet further comprises active nuclides other than uranium.

11. The nuclear fuel pellet of claim 10 , wherein the active nuclides other than uranium comprise thorium (Th), plutonium (Pu), or a mixture thereof.

12. A method of manufacturing a nuclear fuel pellet comprising:
mixing uranium(IV) oxide (UO 2 ) and a manganese (Mn) dopant in the absence of added aluminum (Al) to yield a fuel composition that is substantially free of aluminum;
pressing the fuel composition into a pellet; and
sintering the pellet, the resulting pellet having a Mn atom concentration of about 0.1 wt % to about 1 wt % based on the total weight of the fuel composition.

13. The method of claim 12 , wherein the Mn dopant is derived from a manganese salt having one or more counter anions, the one or more counter anions each comprising an oxide anion, a nitride anion, a stearate anion, a chloride anion, or a hydroxide anion.

14. The method of claim 13 , wherein the Mn dopant is derived from a manganese oxide.

15. The method of claim 14 , wherein the manganese oxide is Mn 2 O 3 .

16. The method of claim 12 , wherein the sintering the pellet is carried out at a temperature of about 1430 K to about 3200 K.

17. The method of claim 16 , wherein the sintering the pellet is carried out at a temperature of about 1700 K to about 2000 K.

18. The method of claim 13 , wherein the mixing the UO 2 and the manganese (Mn) dopant comprises co-milling the UO 2 and the manganese (Mn) dopant to an average particle size of less than 500 μm.

19. The method of claim 12 , wherein the sintering the pellet is carried out at a temperature of 1770 K to 3200 K.

20. The method of claim 12 , wherein the mixing the UO 2 and the manganese (Mn) dopant comprises co-milling the UO 2 and the manganese (Mn) dopant to an average particle size of less than 100 μm.

Assignees

• Los Alamos Nat Security Llc
• Triad Nat Security Llc

Inventors

• Cooper Michael William Donald
• Andersson Anders David Ragnar
• Stanek Christopher Richard

Classifications

• G21C3/62

  Ceramic fuel · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C04B2235/78

  Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures · CPC title

• C04B2235/72

  Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics · CPC title

• C04B2235/3265

  Mn2O3 · CPC title