CASK APPARATUS, SYSTEM AND METHOD FOR TRANSPORTING AND/OR STORING HIGH LEVEL WASTE

• US 20100272225A1
• Filed: 04/28/2010
• Published: 10/28/2010
• Est. Priority Date: 04/28/2009
• Status: Active Grant

• Current Assignee: Holtec International, Inc.
• Original Assignee: Holtec International, Inc.
• Inventors: Singh, Krishna P.
• Granted Patent: US 9,672,948 B2
• Time in Patent Office: Days
• US Class Current: 376/272
• CPC Class Codes: G21F 5/005 Containers for solid radioactive wastes, e.g. for ultimate disposal
• CPC Class Codes: G21F 5/10 Heat-removal systems, e.g. using circulating fluid or cooling fins
• CPC Class Codes: G21F 5/12 Closures for containers; Sealing arrangements

Abstract

A thermally conductive cask for storing high level radioactive waste. In one aspect the invention can be a thermally conductive cask comprising: a gamma shielding cylindrical body forming a cavity for receiving high level radioactive waste and having an outer surface formed of a first material having a first thermal conductivity; a neutron shielding cylindrical body surrounding the gamma shielding cylindrical body and having a layer formed of a second material having a second thermal conductivity that is greater than the first thermal conductivity, the layer forming an inner surface of the neutron shielding cylindrical body; and wherein the layer is clad to the outer surface of the gamma shielding cylindrical body.

Claims

1. A thermally conductive cask comprising:

a cylindrical body comprising;

an inner shell forming a cavity for receiving high level radioactive waste and having a longitudinal axis;

an intermediate shell comprising an inner layer and an outer layer clad to the inner layer, the inner layer constructed of a material having a first thermal conductivity and the outer layer constructed of a material having a second thermal conductivity that is greater than the first thermal conductivity, the intermediate shell circumferentially surrounding the inner shell in a concentric manner so as to form a first annular gap between the inner layer of the intermediate shell and the inner shell;

a first set of radial fins located within the first annular gap and connected to the inner shell and the intermediate shell;

a gamma shielding material filling the first annular gap;

an outer shell circumferentially surrounding the intermediate shell in a concentric manner so as to form a second annular gap between the outer layer of the intermediate shell and the outer shell, the outer shell constructed of the second material;

a second set of radial fins located within the second annular gap and connected to the outer layer of the intermediate shell and the outer shell, the outer shell constructed of the second material; and

a neutron shielding material disposed within the second annular gap;

a lid connected to a top end of the cylindrical body and enclosing a top end of the cavity; and

a base connected to a bottom end of the cylindrical body and enclosing a bottom end of the cavity.

2. The thermally conductive cask of claim 1 wherein the first set of radial fins and the inner shell are constructed of the first material.

3. The thermally conductive cask of claim 2 wherein the first material is a steel and the second material is an aluminum.

4. The thermally conductive cask of claim 1 wherein the first material is carbon steel and the second material is a soft aluminum.

5. The thermally conductive cask of claim 1 wherein the outer layer is clad to the inner layer by explosion bonding.

6. The thermally conductive cask of claim 1 wherein the outer layer and the inner layer are fixedly bonded together and in conformal contact.

7. The thermally conductive cask of claim 1 wherein the first and second sets of radial fins are circumferentially offset from one another.

8. The thermally conductive cask of claim 1 wherein the second set of fins are welded to the outer layer of the intermediate shell and to the outer shell.

9. The thermally conductive cask of claim 1 wherein an outside surface of the outer shell has a topography that increases the overall surface area as opposed to a smooth surface.

10. The thermally conductive cask of claim 9 wherein the topography comprises dimples, ridges and/or undulations.

11. The thermally conductive cask of claim 1 wherein the body comprises a top annular forging connected to a top edge of the inner shell and a top edge of the intermediate shell, the lid connected to the top annular forging, wherein the base is connected to a bottom edge of the inner shell and a bottom edge of the intermediate shell, and wherein the inner shell, the top annular forging and the base are constructed of the, first material.

12. The thermally conductive cask of claim 11 wherein the body comprises a top annular plate and a bottom annular plate, the top and bottom annular plates constructed of the second material, the top annular plate connected to a top edge of the outer shell and to a top material transition zone of the top annular forging, and the bottom annular plate connected to a bottom edge of the outer shell and to a bottom material transition zone of the base.

13. The thermally conductive cask of claim 1 wherein the first and second materials cannot be welded together.

14. A thermally conductive cask comprising:

a gamma shielding cylindrical body forming a cavity for receiving high level radioactive waste and having an outer surface formed of a first material having a first thermal conductivity;

a neutron shielding cylindrical body surrounding the gamma shielding cylindrical body and having a layer formed of a second material having a second thermal conductivity that is greater than the first thermal conductivity, the layer forming an inner surface of the neutron shielding cylindrical body; and

wherein the layer is clad to the outer surface of the gamma shielding cylindrical body.

15. The thermally conductive cask of claim 14 wherein the neutron shielding cylindrical body comprises:

an outer shell formed of the first material;

a set of radial fins connecting the layer and the outer shell, the set of radial fins constructed of the first material; and

a neutron radiation shielding material filling an annular gap between the outer shell and the layer.

16. The thermally conductive cask of claim 15 wherein the first material is a steel and the second material is an aluminum.

17. The thermally conductive cask of claim 14 wherein the layer of the outer neutron shielding cylindrical body is clad to the outer surface of the gamma shielding cylindrical body by explosion bonding.

18. The thermally conductive cask of claim 14 wherein the layer of the outer neutron shielding cylindrical body is fixedly bonded to and in conformal contact with the outer surface of the gamma shielding cylindrical body.

19. The thermally conductive cask of claim 14 further comprising a lid enclosing a top end of the cavity and a base enclosing a bottom end of the cavity.

20. The thermally conductive cask of claim 14 further comprising a fuel basket positioned within the cavity.

21. A thermally conductive cask comprising:

a steel inner shell forming a cavity for receiving high level radioactive waste and having a longitudinal axis;

an intermediate shell comprising an inner steel layer and an outer aluminum layer clad to the inner steel layer, the intermediate shell circumferentially surrounding the inner shell in a concentric manner so as to form a first annular gap between the intermediate shell and the inner steel shell;

a set of steel fins located within the first annular gap and connected to the inner shell and the intermediate shell;

a gamma shielding material filling the first annular gap;

an aluminum outer shell circumferentially surrounding the intermediate shell in a concentric manner so as to form a second annular gap between the aluminum layer and the outer shell;

a set of aluminum radial fins located within the second annular gap and connected to the outer layer of the intermediate shell and the outer shell; and

a neutron shielding material disposed within the second annular gap.

22. The thermally conductive cask of claim 21 wherein the outer layer is clad to the inner layer by explosion bonding.

23. The thermally conductive cask of claim 21 wherein the outer layer is fixedly bonded to and in conformal contact with the inner layer.

24. The thermally conductive cask of claim 21 further comprising a lid enclosing a top end of the cavity and a base enclosing a bottom end of the cavity.

25. The thermally conductive cask of claim 21 further comprising a fuel basket positioned within the cavity.

26. A thermally conductive cask comprising:

a gamma shielding cylindrical body forming a cavity for receiving high level radioactive waste and having an outer surface formed of a first material having a first thermal conductivity;

a neutron shielding cylindrical body surrounding the gamma shielding cylindrical body, the neutron shielding cylindrical body comprising;

a first shell forming an inner surface of the neutron shielding cylindrical body;

a second shell concentrically surrounding the first shell so that an annular gap exists between the first and second shells;

a set of connectors disposed within the annular gap and connected to the first and second shells;

a neutron absorbing material filling the annular gap; and

wherein the first shell, the second shell, and the connectors are constructed of a second material having a second thermal conductivity that is greater than the first thermal conductivity; and

wherein the first shell is clad to the outer surface of the gamma shielding cylindrical body.

27. The thermally conductive case of claim 26 wherein the first material and the second material are metallurgically incompatible for welding

28. The thermally conductive cask of claim 26 wherein the first shell is fixedly bonded to and in conformal contact with the outer surface of the gamma shielding cylindrical body.

29. The thermally conductive cask of claim 26 further comprising a lid enclosing a top end of the cavity and a base enclosing a bottom end of the cavity.