Control rods for light water reactors

Patent metadata

Field	Value
Publication number	US-11289213-B2
Application number	US-201816051712-A
Country	US
Kind code	B2
Filing date	Aug 1, 2018
Priority date	Aug 31, 2017
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

A control rod for a nuclear fuel assembly is described herein that includes a neutron absorbing material having a melting point greater than 1500° C. that does not form a eutectic with a melting point less than 1500° C., and may further include a cladding material having a melting point greater than 1500° C. The cladding material is selected from the group consisting of silicon carbide, zirconium, a zirconium alloy, tungsten, and molybdenum. The absorbing material is selected from the group consisting of Gd2O3, Ir, B4C, Re, and Hf. The metal cladding or the absorbing material may be coated with an anti-oxidation coating of Cr with or without a Nb intermediate layer.

First claim

What is claimed is:

1. A control rod for a nuclear fuel assembly comprising:
a cladding material having a melting point greater than 1500° C.; and
a neutron absorbing material having a melting point greater than 1500° C.; and
an intermediate layer coated on the cladding material,
wherein the intermediate layer is intermediate the cladding material and an outer coating,
wherein the intermediate layer is selected from the group consisting of niobium, molybdenum, and tantalum,

wherein the cladding and the absorbing materials do not form a eutectic that has a melting point less than 1500° C., and
wherein the cladding material and the intermediate layer do not form a eutectic that has a melting point less than 1500° C.

2. The control rod recited in claim 1 wherein the cladding material is silicon carbide.

3. The control rod recited in claim 1
wherein the cladding material is a metal,
wherein the outer coating is an anti-oxidation coating on the intermediate layer,
the cladding material and the anti-oxidation coating do not form a eutectic that has a melting point less than 1500° C.

4. The control rod recited in claim 3 wherein the anti-oxidation coating comprises a chromium outer coating.

5. The control rod recited in claim 4 wherein the intermediate layer is positioned between the chromium outer coating and the cladding material.

6. The control rod recited in claim 1 wherein the cladding material is selected from the group consisting of zirconium, tungsten, molybdenum, and alloys of each.

7. The control rod recited in claim 1 wherein the neutron absorbing material has an effective neutron absorption cross-section equal to or greater than 8 Barns.

8. The control rod recited in claim 1 wherein the absorbing material is Gd 2 O 3 .

9. The control rod recited in claim 8 wherein the Gd 2 O 3 is diluted with an oxide.

10. The control rod recited in claim 9 wherein the oxide is one of Al 2 O 3 or CaO.

11. The control rod recited in claim 1 wherein the neutron absorbing material is selected from the group consisting of B 4 C, Re, Ir, and Hf.

12. A control rod for a nuclear fuel assembly, the control rod comprising:
a cladding material having a melting point greater than 1500° C.; and
a neutron absorbing material having a melting point greater than 1500° C.,
wherein the cladding and absorbing materials do not form a eutectic that has a melting point less than 1500° C.,
wherein the cladding material is a metal coated with an anti-oxidation coating, the anti-oxidation coating and the cladding material do not form a eutectic that has a melting point less than 1500° C., and
wherein the anti-oxidation coating comprises a chromium outer coating and an intermediate layer, the intermediate layer is positioned between the chromium outer coating and the cladding material, and the intermediate layer is selected from the group consisting of niobium, molybdenum, and tantalum.

13. A control rod for a nuclear fuel assembly, the control rod comprising:
a cladding material having a melting point greater than 1500° C.;
a neutron absorbing material having a melting point greater than 1500° C.; and
an anti-oxidation coating coated on the cladding material,
wherein the anti-oxidation coating comprises a chromium outer coating and an intermediate layer, the intermediate layer is positioned between the chromium outer coating and the cladding material, and the intermediate layer is selected from the group consisting of niobium, molybdenum, and tantalum,
wherein the cladding and absorbing materials do not form a eutectic that has a melting point less than 1500° C., and
wherein the anti-oxidation coating and the cladding material do not form a eutectic that has a melting point less than 1500° C.

Assignees

• Westinghouse Electric Co Llc

Inventors

• Lahoda Edward J
• Boylan Frank A
• Lam Ho Q
• Nissley Mitchell E
• Schneider Raymond E
• Oelrich Robert L
• Ray Sumit
• Pomirleanu Radu
• Karoutas Zeses
• Hone Michael J

Classifications

• C23C30/00

  Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence) · CPC title

• G21C11/08

  Thermal shields; Thermal linings, i.e. for dissipating heat from gamma radiation which would otherwise heat an outer biological shield {; Thermal insulation} · CPC title

• G21C1/08

  moderator being highly pressurised, e.g. boiling water reactor, integral super-heat reactor, pressurised water reactor (G21C1/22 takes precedence) · CPC title

• G21C7/08 Primary

  by displacement of solid control elements, e.g. control rods · CPC title

• G21C3/328

  Relative disposition of the elements in the bundle lattice · CPC title