Natural circulation heat removal system for a nuclear reactor with pile structure

1. A nuclear plant, comprising:

a nuclear reactor;

a natural circulation air cooling system defining an air inlet opening, an air outlet opening, and one or more conduits extending in thermal communication with the nuclear reactor between the air inlet opening and the air outlet opening, such that the natural circulation air cooling system is configured to

circulate ambient air from an ambient environment, through the air inlet opening, and into the one or more conduits, and

circulate the ambient air from the one or more conduits, through the air outlet opening, and into the ambient environment, based on the ambient air in the one or more conduits absorbing rejected heat from the nuclear reactor such that a density of the ambient air absorbing the rejected heat in the one or more conduits is reduced in relation to ambient air circulated into the one or more conduits from the ambient environment; and

a pile structure including a first pile structure and a second pile structure each including a pile of packing objects, the first pile structure covering the air inlet opening and the second pile structure covering the air outlet opening such that the air inlet opening and the air outlet opening are obscured from direct exposure to the ambient environment.

2. The nuclear plant of claim 1 , wherein the pile of the packing objects includes a three-dimensional lattice of the packing objects.

3. The nuclear plant of claim 1 , wherein the pile structure further includes a channel structure coupled to and laterally surrounding at least one opening and extending vertically upwards from the at least one opening into an interior of the pile structure, the at least one opening including at least one of the air inlet opening or the air outlet opening, the channel structure having a sidewall defining an interior channel extending vertically from a bottom opening that is proximate to the at least one opening to a top opening that is distal to the at least one opening, such that the channel structure is configured to

direct air to flow between the at least one opening and the top opening through the interior channel, and

inhibit lateral fluid flow to the at least one opening from an exterior of the channel structure.

4. The nuclear plant of claim 3 , wherein

the channel structure includes

a lower solid portion defining a lower portion of the interior channel, and

an upper perforated portion defining an upper portion of the interior channel, and

the upper perforated portion includes one or more perforations extending laterally through a thickness of the sidewall of the channel structure, and the lower solid portion does not include any perforations extending laterally through the thickness of the sidewall of the channel structure, such that the channel structure is configured to

direct air to flow laterally between the upper portion of the interior channel and the exterior of the channel structure, and

inhibit lateral fluid flow to the lower portion of the interior channel from the exterior of the channel structure.

5. The nuclear plant of claim 1 , wherein

the packing objects are associated with a particular angle of repose, and

the pile of the packing objects has an angle of elevation that is equal to or less than about 90% of the particular angle of repose.

6. The nuclear plant of claim 1 , wherein the pile structure includes a net structure extending over at least a portion of the packing objects.

7. The nuclear plant of claim 6 , wherein

the pile structure includes a first sub-pile of the packing objects that covers at least one opening, the at least one opening including at least one of the air inlet opening or the air outlet opening,

the net structure covers the first sub-pile, and

the pile structure further includes a second sub-pile of the packing objects that covers the first sub-pile and the net structure, such that the net structure is located between the first sub-pile and the second sub-pile.

8. The nuclear plant of claim 1 , wherein the pile of packing objects has a packing density that is greater than or equal to about 750 to 1,300 kg/m 3 .

9. The nuclear plant of claim 1 , wherein a maximum cumulative volume of interstitial spacing between adjacent packing objects in the pile of the packing objects is equal to or less than about 60% of a total volume of the pile structure.

10. The nuclear plant of claim 1 , a maximum interstitial spacing between any adjacent packing objects in the pile of the packing objects is equal to or less than about 12 inches.

11. The nuclear plant of claim 1 , wherein the pile structure is configured such that a pressure difference along a given length of a given air flow conduit between at least one opening and the ambient environment through the pile structure is equal to or less than about 2 inches of water gauge per foot of distance through the given air flow conduit, the at least one opening including at least one of the air inlet opening or the air outlet opening.

12. The nuclear plant of claim 1 , wherein the packing objects include

a concrete structure.

13. The nuclear plant of claim 1 , further comprising:

a curb structure at least partially laterally surrounding the pile structure, the curb structure having a vertical height of about 6 inches to about 1 foot, the curb structure configured to mitigate lateral particulate material entry into the pile of the packing objects.

14. The nuclear plant of claim 1 , wherein the pile structure further includes

one or more of activated alumina (Al2O3), activated charcoal, organic wax, plastic, a polymer matrix, or a molten salt.

15. A nuclear plant, comprising:

a nuclear reactor;

a natural circulation air cooling system defining an air inlet opening, an air outlet opening, and one or more conduits extending in thermal communication with the nuclear reactor between the air inlet opening and the air outlet opening, such that the natural circulation air cooling system is configured to

circulate ambient air from an ambient environment, through the air inlet opening, and into the one or more conduits, and

circulate the ambient air from the one or more conduits, through the air outlet opening, and into the ambient environment, based on the ambient air in the one or more conduits absorbing heat rejected from the nuclear reactor such that a density of the ambient air absorbing the heat in the one or more conduits is reduced in relation to ambient air circulated into the one or more conduits from the ambient environment; and

a pile structure covering at least one opening of the air inlet opening or the air outlet opening, the pile structure including a pile of packing objects covering the at least one opening, such that the at least one opening is obscured from direct exposure to the ambient environment by the pile of the packing objects,

the pile structure including

a first pile structure covering the air inlet opening, the first pile structure including a first pile of first packing objects covering the air inlet opening, such that the air inlet opening is obscured from direct exposure to the ambient environment by the first pile of the first packing objects; and

a second pile structure covering the air outlet opening, the second pile structure including a second pile of second packing objects covering the air outlet opening, such that the air outlet opening is obscured from direct exposure to the ambient environment by the second pile of the second packing objects,

the pile structure being one of the first pile structure or the second pile structure, such that the pile of the packing objects is one of the first pile of the first packing objects or the second pile of the second packing objects.

16. The nuclear plant of claim 15 , wherein a maximum vertical elevation of the second pile of the second packing objects is greater than a maximum vertical elevation of the first pile of the first packing objects.

17. A nuclear plant, comprising:

a nuclear reactor;

a natural circulation air cooling system defining an air inlet opening, an air outlet opening, and one or more conduits extending in thermal communication with the nuclear reactor between the air inlet opening and the air outlet opening, such that the natural circulation air cooling system is configured to

circulate ambient air from an ambient environment, through the air inlet opening, and into the one or more conduits, and

circulate the ambient air from the one or more conduits, through the air outlet opening, and into the ambient environment, based on the ambient air in the one or more conduits absorbing heat rejected from the nuclear reactor such that a density of the ambient air absorbing the heat in the one or more conduits is reduced in relation to ambient air circulated into the one or more conduits from the ambient environment; and

a pile structure covering at least one opening of the air inlet opening or the air outlet opening, the pile structure including a pile of packing objects covering the at least one opening, such that the at least one opening is obscured from direct exposure to the ambient environment by the pile of the packing objects, the pile structure covering both the air inlet opening and the air outlet opening, such that both the air inlet opening and the air outlet opening are obscured from direct exposure to the ambient environment by the pile of packing objects

the pile structure including a wall structure, the wall structure at least partially located within the pile of the packing objects and at least partially obscured from direct exposure to the ambient environment by the packing objects, the wall structure located laterally between the air inlet opening and the air outlet opening such that opposite sidewalls of the wall structure are proximate to separate, respective openings of the air inlet opening or the air outlet opening.

18. A system, comprising:

a heat source and/or structure located at least partially below a local ground surface elevation, the heat source and/or structure configured to generate heat at a location that is below the local ground surface elevation;

an air cooling system defining an air inlet opening, an air outlet opening, and one or more conduits extending in thermal communication with the heat source and/or structure, at the location that is below the local ground surface elevation where the heat is generated, between the air inlet opening and the air outlet opening, such that the air cooling system is configured to

circulate ambient air from an ambient environment, through the air inlet opening, and into the one or more conduits, and

circulate the ambient air from the one or more conduits, through the air outlet opening, and into the ambient environment, based on the ambient air in the one or more conduits absorbing heat rejected from the heat source and/or structure; and

a pile structure covering at least one opening of the air inlet opening or the air outlet opening, the pile structure including a pile of packing objects covering the at least one opening, such that the at least one opening is obscured from direct exposure to the ambient environment by the pile of the packing objects, the pile structure including

a first pile structure covering the air inlet opening, the first pile structure including a first pile of first packing objects covering the air inlet opening, such that the air inlet opening is obscured from direct exposure to the ambient environment by the first pile of the first packing objects; and

a second pile structure covering the air outlet opening, the second pile structure including a second pile of second packing objects covering the air outlet opening, such that the air outlet opening is obscured from direct exposure to the ambient environment by the second pile of the second packing objects,

the pile structure being one of the first pile structure or the second pile structure, such that the pile of the packing objects is one of the first pile of the first packing objects or the second pile of the second packing objects.