ENVIRONMENTALLY SEQUESTERED SPENT FUEL POOL
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.
1 . A spent fuel pool system comprising:
a fuel pool comprising:
a base slab;
a plurality of vertical sidewalls extending from the base slab; and
a cavity defined by the vertical sidewalls and the base slab, the cavity being at least partially filled with pool water;
a pool liner system located within the cavity, the pool liner system comprising:
an outer liner positioned adjacent to the vertical sidewalls;
an inner liner positioned adjacent to the outer liner such that the inner liner is in contact with the pool water; and
wherein the inner and outer liners are separated by an air gap.
2 . The spent fuel pool system according to claim 1 wherein both of the inner and outer liners are positioned within the cavity of the fuel pool.
3 . The spent fuel pool system according to claim 1 further comprising an embedment plate embedded into the vertical sidewalls and circumscribing the cavity, the embedment plate comprising an inner surface that faces the cavity.
4 . The spent fuel pool system according to claim 3 wherein the inner liner is sealably coupled to the inner surface of the embedment plate at a first position and the outer liner is sealably coupled to the inner surface of the embedment plate at a second position, the first position being closer to an open top end of the cavity than the second position.
5 . The spent fuel pool system according to claim 4 wherein a hermetically sealed flow plenum is formed between a top terminal edge of the inner liner and a top terminal edge of the outer liner, wherein the flow plenum is in fluid communication with the air gap.
6 . The spent fuel pool system according to claim 5 further comprising a flow passageway formed through the embedment plate, a first end of the flow passageway being fluidly coupled to the flow plenum.
7 . The spent fuel pool system according to claim 6 further comprising a vacuum system located outside of the cavity of the fuel pool, the vacuum system comprising a vacuum pump that is fluidly coupled to the air gap by way of the flow passageway of the embedment plate.
8 . The spent fuel pool system according to claim 7 wherein the vacuum pump is configured to maintain the air gap at a vacuum pressure.
9 . The spent fuel pool system according to claim 8 further comprising a pressure sensor configured to detect any rise in pressure within the air gap that would be indicative of a potential leak in the pool liner system.
10 . The spent fuel pool system according to claim 5 wherein the flow plenum extends around an entire perimeter of the spent fuel pool.
11 . The spent fuel pool system according to claim 1 wherein the air gap extends interrupted from an inner surface of the outer liner that faces away from the vertical sidewalls and towards the cavity to an outer surface of the inner liner that faces away from the cavity and towards the vertical sidewalls.
12 . The spent fuel pool system according to claim 1 further comprising a plurality of storage racks disposed on the base slab and submerged in the pool water, each of the storage racks having a plurality of cells each configured for holding a spent nuclear fuel assembly containing nuclear fuel rods.
13 . The spent fuel pool system according to claim 1 wherein the inner and outer liners are located entirely within the cavity of the fuel pool.
14 . A spent fuel pool system comprising:
a fuel pool comprising:
a base slab;
a plurality of vertical sidewalls extending from the base slab; and
a cavity defined by the base slab and an inner surface of the vertical sidewalls, the cavity being filled with pool water;
a pool liner system comprising:
an outer liner positioned adjacent to the inner surfaces of the vertical sidewalls; and
an inner liner positioned adjacent to the outer liner, the inner liner being spaced apart from the outer liner by an air gap, and wherein the inner liner is in contact with the pool water; and
a vacuum system fluidly coupled to the air gap, the vacuum system comprising a vacuum pump that is configured to maintain the air gap at a vacuum pressure.
15 . The spent fuel pool system according to claim 14 further comprising a pressure sensor configured to detect any rise in pressure within the air gap that would be indicative of a potential leak in the pool liner system.
16 . The spent fuel pool system according to claim 14 further comprising a flow plenum formed between a top terminal edge of the outer liner and a top terminal edge of the inner liner, the flow plenum being fluidly coupled to the air gap between the inner and outer liners.
17 . The spent fuel pool system according to claim 16 wherein the vacuum pump is fluidly coupled to the air plenum through a flow passageway formed into an embedment plate that is embedded within the vertical sidewalls.
18 . A spent fuel pool system comprising:
a base slab;
a plurality of vertical sidewalls extending from the base slab;
a cavity defined by the vertical sidewalls and the base slab, the cavity being filled with pool water;
at least one fuel storage rack disposed in the cavity, the fuel storage rack holding a nuclear spent fuel assembly containing nuclear fuel rods that heat the pool water;
a pool liner system located in the cavity and comprising an outer liner adjacent the sidewalls and base slab, an inner liner adjacent the outer liner and wetted by the pool water, and an interstitial space formed between the outer and inner liners; and
a vacuum pump fluidly coupled to the interstitial space, the vacuum pump being configured to evacuate air from the interstitial space to maintain a pressure of the interstitial space below atmospheric pressure.
19 . The spent fuel pool system according to claim 18 further comprising a pressure sensor configured to detect any rise in pressure within the air gap that would be indicative of a potential leak in the pool liner system.
20 . The spent fuel pool system according to claim 19 , further comprising a computer processor based plant monitoring system operably coupled to the pressure sensor to monitor the pressure of the interstitial space.