ALTERNATE PASSIVE SPENT FUEL POOL COOLING SYSTEMS AND METHODS

• US 20140219411A1
• Filed: 02/06/2013
• Published: 08/07/2014
• Est. Priority Date: 02/06/2013
• Status: Active Grant

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: DEDERER, JEFFREY T., BROWN, WILLIAM L., VEREB, FRANK
• Granted Patent: US 9,646,726 B2
• Time in Patent Office: Days
• US Class Current: 376/299
• CPC Class Codes: G21C 15/18 Emergency cooling arrangements; Removing shut-down heat
• CPC Class Codes: G21C 19/07 Storage racks; Storage pools
• CPC Class Codes: G21D 3/06 responsive to faults within the plant in the reactor G21C9/00
• CPC Class Codes: Y02E 30/00 Energy generation of nuclear origin
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

The present invention relates to passive cooling systems and methods for cooling a spent fuel pool in a nuclear power plant in the absence of onsite and offsite power, e.g., in a station blackout event. The systems include a gap formed along the periphery of the spent fuel pool, a heat sink, one or more thermal conductive members, a water supply system for delivering water to at least partially fill the gap and conduct heat generated from the spent fuel pool through the gap to at least one thermal conductive member for transporting heat to the heat sink, and a thermal switch mechanism for activating and deactivating the water supply system.

In particular, the passive spent fuel pool cooling systems and methods of the invention are useful when the active spent fuel pool cooling system is unavailable or inoperable.

Claims

1. A passive cooling system for a spent fuel pool in a nuclear power plant, to provide cooling in the absence of onsite and offsite power, the system comprising:

a gap having a first side and a second side formed at least partially along a periphery of the spent fuel pool;

a heat sink;

one or more thermal conductive members having a first end connected to the second side of the gap and a second end connected to the heat sink, said one or more members structured to transport heat from the gap to the heat sink;

a water supply system, comprising;

a water source; and

a discharge header having a first end connected to the water source and a second end connected to the gap; and

a thermal switch mechanism having an activate position and a deactivate position, structured to deliver water from the water system, into the gap when in the activate position and structured to inhibit the release of water from the water system and into the gap when in the deactivate position.

wherein when the thermal switch mechanism is in the activate position, heat generated in the spent fuel pool is conducted to the gap, transported through the one or more conductive members and to the heat sink.

2. The passive cooling system of claim 1 further comprising one or more conductive cooling fins attached to the second end of the one or more members to enhance transport of the heat from the members to the heat sink.

3. The passive cooling system of claim 1 wherein a valve is located in the discharge header and structured to be positioned in the open position to allow the flow of water in the gap and in the closed position to inhibit the flow of water in the gap.

4. The passive cooling system of claim 1 wherein the nuclear power plant contains a pressurized water reactor.

5. The passive cooling system of claim 1 wherein the first side of the gap is formed by a spent fuel pool liner.

6. The passive cooling system of claim 1 wherein the second side of the gap is formed by a concrete wall.

7. The passive cooling system of claim 1 wherein the gap is continuous.

8. The passive cooling system of claim 1 wherein the gap is partitioned into a plurality of channels.

9. The passive cooling system of claim 1 wherein the discharge header is located at the top or near the top of the gap.

10. The passive cooling system of claim 8 wherein each of said plurality of channels has a discharge header located therein.

11. The passive cooling system of claim 1 wherein the thermal switch can activate in response to a loss of offsite power event with or without availability of emergency diesels operable to supply AC electrical power to active spent fuel pool cooling pumps.

12. The passive cooling system of claim 1 wherein the thermal switch can activate in response to a station blackout when all backup sources of DC electrical power are exhausted.

13. The passive cooling system of claim 1 wherein the heat sink can be selected from the group consisting of a mass of earth, a mass of concrete or other material used in foundations or floors of spent fuel pool structures and combinations thereof.

14. A method of passively cooling a spent fuel pool in a nuclear power plant in the absence of onsite and offsite power, comprising:

forming a gap having a first side and a second side at least partially along a periphery of the spent fuel pool;

providing a heat sink;

at least partially filling the gap with water;

conducting heat from the spent fuel pool through an at least partially water-filled gap; and

transporting the heat from the at least partially water-filled gap to the heat sink.

15. The method of claim 14 wherein at least partially filling the gap with water comprises:

obtaining a water source;

discharging water from the water source into a discharge header which is connected to the water source; and

discharging the water from the discharge header into the gap.

16. The method of claim 15 wherein the discharge header comprises a flow control valve having an open position and a closed position.

17. The method of claim 14 wherein the gap is partitioned into a plurality of channels.

18. The method of claim 14 wherein the discharge header is located at the top or near the top of the gap.

19. The method of claim 17 wherein each of said plurality of channels has a discharge header located therein.

20. The method of claim 14 wherein transporting heat from the gap to the heat sink, comprises:

obtaining at least one thermal conductive member having one end and another end;

attaching the one end to the second side of the gap and the other end to the heat sink; and

conducting the heat through the gap and transporting the heat through the at least one thermal conductive member to said heat sink.