System and method for minimizing movement of nuclear fuel racks during a seismic event

Patent metadata

Field	Value
Publication number	US-11017908-B2
Application number	US-201815973966-A
Country	US
Kind code	B2
Filing date	May 8, 2018
Priority date	Aug 28, 2012
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

A system for storing nuclear fuel, the system including a storage rack and a bearing pad. The storage rack includes an array of cells, each cell configured to receive and store nuclear fuel rods, a base plate configured to support the array of cells, and a support structure configured to support the base plate and to allow cooling fluid to circulate under and up through apertures in the base plate. The bearing pad is coupled to the support structure and is configured to limit lateral movement of the storage rack independent from lateral movement of the bearing pad. The base plate defines a base plate profile in a horizontal plane of the base plate, and the bearing pad defines a bearing pad profile in the horizontal plane of the base plate, wherein the bearing pad profile extends outside of the base plate profile.

First claim

What is claimed is:

1. A system for storing nuclear fuel in a storage pool, the system comprising:
a storage rack including an array of cells and a base plate supporting the array of cells, the base plate defining a horizontal plane;
each cell configured to receive and store nuclear fuel rods; and
a bearing pad configured for placement on a bottom surface of the storage pool, the bearing pad comprising a plurality of upward-extending support columns each engaging a corresponding one of a plurality of downwardly open receptacles on the base plate;
wherein the support columns elevate the base plate of the storage rack above the bearing pad to allow cooling fluid to circulate under and upwards through apertures in the base plate;
wherein the support columns include top beveled edges to act as a guide surface, and the receptacles include a lower beveled edge to similarly act as a guide surface when the support columns are inserted into the receptacles.

2. The system of claim 1 , wherein engagement between the support columns and receptacles limit lateral movement of the storage rack with respect to the bearing pad during a seismic event.

3. The system of claim 1 , wherein the receptacles are formed by downward-extending protrusions projecting downward from the base plate.

4. The system of claim 1 , wherein the bearing pad is positioned on the bottom surface of the storage pool, and wherein the bearing pad includes a flat bottom surface configured to slide on the bottom surface of the storage pool.

5. The system of claim 1 , further comprising a collar extending laterally outward from sides of the storage rack and attached adjacent a top of the storage rack.

6. The system of claim 5 , wherein the collar is spaced vertically apart from the base plate at a bottom of the storage rack.

7. The system of claim 6 , wherein the collar extends parametrically completely around the storage rack.

8. The system of claim 5 , wherein the collar defines a spacer profile in the horizontal plane of the base plate, and the base plate defines a base plate profile that extends outside farther than the spacer profile.

9. A system for storing nuclear fuel, the system comprising:
a first storage rack;
a second storage rack arranged in a fuel pool adjacent to the first storage rack;
each storage rack comprising:
an array of cells configured to receive and store nuclear fuel rods, each cell having an open top for insertion of the fuel rods;
a base plate at a bottom of the cells configured to support the array of cells of the respective storage rack, the base plate defining a horizontal plane; and
a collar extending parametrically around and protruding laterally outwards from sides of the storage rack which defines a spacer, the collar spaced vertically above the base plate;

a bearing pad supporting the first and second storage racks, each bearing pad configured for placement on a bottom surface of a fuel storage pool;
wherein the bearing pad comprises a plurality of upward-extending support columns each engaging a corresponding one of a plurality of downwardly open receptacles on the base plate;
wherein the support columns elevate the base plate of the storage rack above the bearing pad to allow cooling fluid to circulate under and upwards through apertures in the base plate into the cells;
wherein the receptacles are formed by downward-extending protrusions projecting downward from the base plates of the first and second storage racks;
wherein the support columns include top beveled edges to act as a guide surface, and the receptacles include a lower beveled edge to similarly act as a guide surface when the support columns are inserted into the receptacles.

10. The system of claim 9 , wherein engagement between the support columns and receptacles limit lateral movement of the storage rack with respect to the bearing pad during a seismic event.

11. The system of claim 9 , wherein the bearing pad is configured to maintain a first predetermined distance between the respective base plates of the first and second storage racks.

12. The system of claim 9 , wherein the collar on the first storage rack is arranged to engage the collar on the second storage rack during a seismic event.

13. The system of claim 12 , wherein the base plate on the first storage rack is positioned to engage the base plate of the second rack during the seismic event.

14. The system of claim 13 , wherein base plates of the first and second storage rack extend laterally outwards from the sides of the first and second storage racks farther than the collars.

15. The system of claim 9 , wherein the base plate defines a base plate profile in the horizontal plane of the base plate, and the bearing pad defines a bearing pad profile in the horizontal plane of the base plate, and wherein the bearing pad profile extends laterally outside of the base plate profile.

16. The system of claim 15 , wherein the collar defines a spacer profile in the horizontal plane of the base plate, and the base plate profile extends laterally outside farther than the spacer profile.

17. A system for storing nuclear fuel, the system comprising:
a first storage rack;
a second storage rack arranged in a fuel pool adjacent to the first storage rack;
each storage rack comprising:
an array of cells configured to receive and store nuclear fuel rods, each cell having an open top for insertion of the fuel rods;
a base plate at a bottom of the cells configured to support the array of cells of the respective storage rack, the base plate defining a horizontal plane; and
a collar extending parametrically around and protruding laterally outwards from sides of the storage rack which defines a spacer, the collar spaced vertically above the base plate;

a bearing pad supporting the first and second storage racks, each bearing pad configured for placement on a bottom surface of a fuel storage pool;
the bearing pad comprising a plurality of upward-extending support columns each engaging a corresponding one of a plurality of downwardly open receptacles on the base plate;
the support columns elevating the base plate of the storage rack above the bearing pad to allow cooling fluid to circulate under and upwards through apertures in the base plate into the cells;
the collar on the first storage rack arranged to engage the collar on the second storage rack during a seismic event, and the base plate on the first storage rack is positioned to engage the base plate of the second rack during the seismic event;

wherein base plates of the first and second storage rack extend laterally outwards from the sides of the first and second storage racks farther than the collars.

Assignees

• Holtec Int Inc
• Holtec International

Inventors

• Singh Krishna P
• Bullard Ii Charles W

Classifications

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21C19/07 Primary

  Storage racks; Storage pools · CPC title

• G21C19/40

  Arrangements for preventing occurrence of critical conditions, e.g. during storage · CPC title

• G21C19/34

  Apparatus or processes for dismantling nuclear fuel, e.g. before reprocessing {; Apparatus or processes for dismantling strings of spent fuel elements}(shielded cells G21F7/00) · CPC title