Environmentally sequestered spent fuel pool

Patent metadata

Field	Value
Publication number	US-10468145-B2
Application number	US-201514877217-A
Country	US
Kind code	B2
Filing date	Oct 7, 2015
Priority date	Oct 7, 2014
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

An environmentally sequestered nuclear spent fuel pool in one embodiment includes sidewalls and a base slab that confine a water impoundment. The pool includes fuel racks containing spent fuel assemblies which heat the water via radioactive decay. A dual liner system enclosing the pool forms an impervious barrier providing redundant provisions for preventing leakage of contaminated pool water into the environment. An interstitial space is formed between the liners which may be maintained at sub-atmospheric pressures by a vacuum pump system that evacuates the space. By maintaining the pressure in the space at a negative pressure with corresponding boiling point less than the temperature of the pool water, any leakage through the inner-most liner into the interstitial space will vaporize and be extracted via the pump for signaling a potential leak in the liner system.

First claim

What is claimed is:

1. An environmentally sequestered nuclear spent fuel pool system comprising:
a base slab;
a plurality of vertical sidewalls extending upwards from and adjoining the base slab, the sidewalls comprising an inner surface and a top surface;
a cavity that holds pool water defined by the inner surface of the sidewalls and the base slab, the cavity having an open top end;
a pool liner system comprising an outer liner having an outer surface adjacent to the inner surface of the sidewalls and an inner surface that faces the cavity, an inner liner having an outer surface adjacent to the inner surface of the outer liner and an inner surface that faces the cavity and is wetted by the pool water, and an interstitial space formed between the outer surface of the inner liner and the inner surface of the outer liner, the interstitial space forming an air gap between the inner and outer liners that extends uninterrupted from the inner surface of the outer liner to the outer surface of the inner liner, each of the inner and outer liners terminating at a top terminal end;
a top embedment plate circumscribing the cavity at a top surface of the sidewalls and adjoining the cavity without closing the open top end of the cavity, the top embedment plate comprising an inner vertical side facing the cavity and an opposite outer vertical side embedded within the sidewalls;
wherein the top terminal end of the inner liner is sealably attached to the inner vertical side of the top embedment plate at a first seal location and the top terminal end of the outer liner is sealably attached to the inner vertical side of the top embedment plate at a second seal location such that a hermetically sealed top flow plenum is formed between the first and second seal locations; and
wherein the top flow plenum is in fluid communication with the interstitial space.

2. The spent fuel pool system according to claim 1 , wherein a horizontal portion of the inner and outer liners extend across and covers the base slab between opposing sidewalls, the horizontal portions of the inner and outer liners and portions covering the sidewalls forming a continuous barrier encapsulating the pool water.

3. The spent fuel pool system according to claim 1 , wherein one vertical side of the top flow plenum is bounded by a portion of the outer surface of the inner liner and an opposing vertical side of the top flow plenum is bounded by a portion of the inner vertical side of the top embedment plate.

4. The spent fuel pool system according to claim 1 , wherein the top flow plenum extends around an entire perimeter of the spent fuel pool.

5. The spent fuel pool system according to claim 1 , further comprising a flow passageway formed through the top embedment plate that is in fluid communication with the top flow plenum, the flow passageway having an outlet end penetrating a top surface of the top embedment plate.

6. The spent fuel pool system according to claim 1 , wherein the top embedment plate has a horizontal thickness greater than a thickness of the inner and outer liners combined.

7. The spent fuel pool system according to claim 1 , wherein the top terminal ends of the inner and outer liners are welded separately and directly to the top embedment plate.

8. The spent fuel pool system according to claim 1 , wherein the inner liner, the outer liner, and the top embedment plate are made of the same metallic material.

9. The spent fuel pool system according to claim 1 , further comprising at least one fuel storage rack disposed on the base slab, the storage rack having a plurality of cells each configured for holding a spent nuclear fuel assembly containing nuclear fuel rods.

10. The spent fuel pool system according to claim 1 wherein the outer surface of the inner liner and the inner surface of the outer liner are both exposed directly to the air gap.

11. The spent fuel pool system according to claim 1 wherein the outer vertical side of the top embedment plate is directly adjacent to a recessed portion of the inner surface of the sidewalls.

12. The spent fuel pool system according to claim 11 wherein a top surface of the embedment plate is substantially flush with the top surface of the sidewalls.

13. The spent fuel pool system according to claim 1 wherein a height of the inner liner measured from a top surface of the base slab to the top terminal end of the inner liner is greater than a height of the outer liner measured from the top surface of the base slab to the top terminal end of the outer liner.

14. A nuclear spent fuel pool system comprising:
a base slab having a top surface;
a plurality of vertical sidewalls extending upwards from the top surface of the base slab, each of the sidewalls having an inner surface and an outer surface opposite the inner surface;
a cavity that holds pool water collectively defined by the inner surfaces of the sidewalls and the top surface of the base slab;
a pool liner system comprising:
an outer liner having a first surface disposed against the inner surface of the sidewalls and an opposite second surface that faces the cavity; and
an inner liner having a first surface facing the second surface of the outer liner and an opposite second surface that faces the cavity and is wetted by the pool water, wherein the first surface of the inner liner is spaced apart from the second surface of the outer liner thereby forming an interstitial space between the inner and outer liners;
an embedment plate embedded into the sidewalls and having a top surface; and
the inner liner terminating at a top terminal edge that is spaced a first distance from the top surface of the embedment plate and the outer liner terminating at a top terminal edge that is spaced a second distance from the top surface of the embedment plate, the second distance being greater than the first distance;
a first seal weld coupling the top terminal edge of the inner liner to the embedment plate; a second seal weld coupling the top terminal edge of the outer liner to the embedment plate; and
a flow plenum defined between the first and second seal welds and between the embedment plate and a portion of the inner liner that protrudes above the top terminal end of the outer liner.

15. The spent fuel pool system according to claim 14 wherein the embedment plate extends from a bottom surface to the top surface, and wherein the bottom surface of the embedment plate is located between the top terminal edges of the inner and outer liners and the top surface of the base slab, each of the inner and outer liners coupled to the embedment plate along a vertical surface of the embedment plate that faces the cavity and extends between the top and bottom surfaces of the embedment plate.

16. The spent fuel pool system according to claim 14 wherein the top surface of the embedment plate is substantially flush with a top surface of the sidewalls, and wherein the embedment plate comprises a first surface facing the cavity and an opposite second surface, and wherein the first surface of the embedment plate is substantially flush with the inner surfaces of the sidewalls.

17. The spent fuel pool system according to claim 14 wherein the interstitial space forms an air gap that extends uninterrupted between the first surface of the inner liner and the second surface of the outer liner.

18. An environmentally sequestered nuclear spent fuel pool system comprising:
a base slab;
at least one sidewall extending upwards from the base slab, the sidewall having an inner surface;
a cavity defined by the inner surface of the sid

Assignees

• Holtec International

Inventors

• Singh Krishna P

Classifications

• G21C13/10

  Means for preventing contamination in the event of leakage, {e.g. double wall} · CPC title

• G21C19/07 Primary

  Storage racks; Storage pools · CPC title

• G21C17/002

  Detection of leaks (by testing the coolant or the moderator G21C17/04) · CPC title

• Y02E30/40

  Cross-Sectional Technologies · mapped topic

• G01M3/00

  Investigating fluid-tightness of structures · CPC title