CANISTER APPARATUS AND BASKET FOR TRANSPORTING, STORING AND/OR SUPPORTING SPENT NUCLEAR FUEL

• US 20080069291A1
• Filed: 09/06/2007
• Published: 03/20/2008
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: Holtec International, Inc.
• Original Assignee: Holtec International, Inc.
• Inventors: Singh, Krishna, Agace, Stephen
• Granted Patent: US 8,135,107 B2
• Time in Patent Office: Days
• US Class Current: 376/272
• CPC Class Codes: G21F 5/00 Transportable or portable shielded containers
• CPC Class Codes: G21F 5/005 Containers for solid radioactive wastes, e.g. for ultimate disposal
• CPC Class Codes: G21F 5/008 Containers for fuel elements
• CPC Class Codes: G21F 5/012 Fuel element racks in the containers
• 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 canister apparatus, basket apparatus and combinations thereof for transporting and/or storing high level radioactive waste, such as spent nuclear fuel. The canister apparatus comprises a cavity for receiving the spent nuclear fuel that is surrounded by two independent gas-tight containment boundaries. The structures that form the two independent gas-tight containment boundaries are in substantially continuous surface contact with one another, thereby facilitating sufficient heat removal from the cavity. In another aspect, the invention is a basket apparatus having a plurality of disk-like grates arranged in a stacked and spaced arrangement so that the cells of the disk-like grates are aligned. In still another aspect, the invention can be a basket apparatus having a disk-like grate having a ring-like structure encompassing a gridwork of beams specially arranged to achieve a unique cell configuration.

Claims

1. A canister apparatus for storing and/or transporting spent nuclear fuel rods comprising:

a first pressure vessel comprising a first shell forming a first cavity for receiving spent nuclear fuel rods, a first plate connected to the first shell so as to enclose a first end of the first cavity, and a first lid connected to the first shell so as to enclose a second end of the first cavity;

a second pressure vessel comprising a second shell forming a second cavity, a second plate connected to the second shell so as to enclose a first end of the second cavity, and a second lid connected to the second shell so as to enclose a second end of the second cavity; and

the first pressure vessel located within the second cavity so that an inner surface of the second shell is in substantially continuous surface contact with an outer surface of the first shell.

2. The canister apparatus of claim 1 further comprising a fuel basket positioned within the first cavity for supporting a plurality of spent nuclear fuel rods.

3. The canister apparatus of claim 1 wherein the first shell and the second shell are constructed of a metal.

4. The canister apparatus of claim 3 wherein the substantially continuous surface contact is achieved by an explosive joining, a cladding process, a roller bonding process, a mechanical compression process, or a combination thereof.

5. The canister apparatus of claim 3 wherein the first shell is made of a metal having a first coefficient of thermal expansion and the second shell is made of a metal having a second coefficient of thermal expansion, wherein the first coefficient of thermal expansion is equal to or greater than the second coefficient of thermal expansion.

6. The canister apparatus of claim 1 further comprising:

an inner surface of the second plate being in substantially continuous surface contact with an outer surface of the first plate; and

an inner surface of the second lid being in substantially continuous surface contact with an outer surface of the first lid.

7. The canister apparatus of claim 1 further comprising:

the first shell, the first plate, the first lid, the second shell, the second plate and the second lid constructed of a metal; and

all connections between the first shell, the first plate and the first lid are accomplished via through-thickness welds; and

all connections between the second shell, the second plate and the second lid are accomplished via through-thickness welds.

8. The canister apparatus of claim 1 further comprising:

the first pressure vessel having an outer surface and the second pressure vessel having an inner Surface; and

wherein the entirety of the outer surface of the first pressure vessel is in substantially continuous surface contact the inner surface of the second pressure vessel.

9. The canister apparatus of claim 1 further comprising:

the first shell having a first edge, a second edge and a first axial length;

the second shell having a first edge, a second edge and a second axial length that is greater than the first axial length; and

the first pressure vessel positioned within the second cavity so that the first and second edges of the second shell extend beyond the first and second edges of the first shell respectively.

10. The canister apparatus of claim 1 further comprising:

a plurality of elongated tubes located within the first cavity; and

each of the elongated tubes comprising a tubular body forming a space for receiving spent nuclear fuel rods and a ventilated cap having at least one hole forming a passageway from the first cavity into the space.

11. The canister apparatus of claim 10 further comprising a plurality of poison rods located within the first cavity between the elongated tubes.

12. The canister apparatus of claim 1 wherein the first and second shells are cylindrical and constructed of metal.

13. The canister apparatus of claim 1 wherein the first cavity comprises an inert gas atmosphere.

14. A canister apparatus for storing and/or transporting spent nuclear fuel rods comprising:

a first metal pressure vessel having an outer surface and forming a cavity for receiving spent nuclear fuel rods;

a second metal pressure vessel having an inner surface; and

the first pressure vessel located within the second pressure vessel so that a substantial entirety of the outer surface of the first metal pressure vessel is in substantially continuous surface contact with the inner surface of the second metal pressure vessel.

15. A canister apparatus for storing and/or transporting spent nuclear fuel rods comprising:

a first structural assembly forming a cavity for receiving spent nuclear fuel rods, the first structural assembly forming a first gas-tight containment boundary surrounding the cavity;

a second structural assembly surrounding the first structural assembly, the second structural assembly forming a second gas-tight containment boundary surrounding the cavity; and

wherein the first structural assembly and second structural assembly are in substantially continuous surface contact with one another.

16. A basket apparatus for supporting a plurality of spent nuclear fuel rods within a containment structure comprising:

a plurality of disk-like grates, each disk-like grate having a plurality of cells formed by a gridwork of beams; and

means for supporting the disk-like grates in a spaced arrangement with respect to one another and so that the cells of the disk-like grates are aligned.

17. The basket apparatus of claim 16 wherein the plurality of cells of each disk-like grate comprise fuel cells and poison rod cells, the fuels cells being larger than the poison rod cells.

18. The basket apparatus of claim 17 further comprising a plurality of poison rods extending through the poison rod cells of the disk-like grates.

19. The basket apparatus of claim 16 further comprising:

the disk-like grates comprising a ring-like structure encompassing the gridwork of beams;

the gridwork of beams comprising a first series of parallel beams, a second series of parallel beams and a third series of parallel beams; and

wherein the first, second and third series of parallel beams are arranged in the ring-like structures so as to intersect and form the plurality of cells.

20. The basket apparatus of claim 16 further comprising:

the disk-like grates comprising a ring-like structure encompassing the gridwork of beams; and

the gridwork of beams comprising a first series of parallel beams, a second series of parallel beams and a third series of parallel beams; and

wherein the gridwork of beams for wherein the first, second and third series of parallel beams are arranged in the ring-like structures so as to intersect and form a plurality of hexagonal shaped cells and a plurality of triangular shaped cells.

21. The basket apparatus of claim 20 further comprising:

a plurality of poison rods extending through the triangular shaped cells; and

a plurality of fuel tubes extending through the hexagonal shaped cells.

22. The basket apparatus of claim 16 wherein the means for supporting the disk-like grates in the spaced arrangement comprises a plurality of tie-rods having tubular spacers.

23. The basket apparatus of claim 16 wherein the beams are rectangular strips of metal having notches, the notches arranged on the rectangular strips so that when the strips are arranged in the desired gridwork, the notches of the strips are aligned and the strips slidably mate with one another.

24. A basket apparatus for supporting a plurality of spent nuclear fuel rods within a containment structure comprising:

a disk-like grate having a ring-like structure encompassing a gridwork of beams;

the gridwork of beams comprising a first series of parallel beams, a second series of parallel beams and a third series of parallel beams; and

wherein the first, second and third series of parallel beams are arranged in the ring-like structures so as to intersect and form a plurality of cells.

25. The basket apparatus of claim 24 wherein the first, second and third series of parallel beams are arranged in the ring-like structures so as to intersect and form a first set of cells having a first shape and a second set of cells having a second shape.

26. The basket apparatus of claim 25 wherein the first set of cells are hexagonal shaped and the second set of sells are triangular shaped.

27. The basket apparatus of claim 24 wherein the first, second and third series of parallel beams are arranged in the ring-like structures so that:

(i) the first and second series of parallel beams intersect with one another;

(ii) the first and third series of parallel beams intersect with one another; and

(iii) the third and second series of parallel beams intersect with one another.

28. The basket apparatus of claim 24 further comprising:

a plurality of the disk-like grates arranged in a stacked and spaced orientation;

spacers located between the disk-like grates, the spacers maintaining separation between the disk-like structures.

29. A basket apparatus for supporting a plurality of spent nuclear fuel rods within a containment structure comprising:

a disk-like grate having a ring-like structure encompassing a gridwork of beams; and

the gridwork of beams forming a first set of cells having a first shape and a second set of cells having a second shape.

30. The basket apparatus of claim 29 wherein the first set of cells are hexagonal shaped and the second set of sells are triangular shaped.