Systems and methods for loading and transferring spent nuclear fuel

• US 20080137794A1
• Filed: 12/01/2005
• Published: 06/12/2008
• Est. Priority Date: 12/01/2005
• Status: Abandoned Application

• Current Assignee: NAC International Inc. (Hitachi Zosen Corporation)
• Original Assignee: NAC International Inc. (Hitachi Zosen Corporation)
• Inventors: Danner, Tom, Tjersland, Gary, Carver, George, Pennington, Charles W.
• Application Number:
  US11/291,727
• Publication Number:
  US 20080137794A1
• Time in Patent Office: Days
• US Class Current: 376/272
• CPC Class Codes: G21C 19/04 Means for controlling flow of coolant over objects being handled; Means for controlling flow of coolant through channel being serviced , e.g. for preventing "blow-out"
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

Disclosed are systems and methods for loading and transferring spent nuclear fuel. In one embodiment, among others, the system comprises a transfer cask that contains spent nuclear fuel and shields radioactivity of the spent nuclear fuel, and an immersion tank that receives transfer casks within. The immersion tank has fluid that is circulated in the immersion tank, thereby cooling and providing shielding for the received transfer cask containing the spent nuclear fuel.

Claims

1. A system for loading and transferring spent nuclear fuel, comprising:

a canister having a first sidewall that has a first height, the canister being operative to contain spent nuclear fuel;

a transfer cask having a second sidewall that has a second height, the transfer cask being operative to contain the canister and to shield radioactivity of the spent nuclear fuel, the transfer cask that contains the canister being operative to hp placed in a spent fuel pool, the spent fuel pool having a depth that is at least twice the height of the canister and transfer cask; and

an immersion tank having a third sidewall that has a third height, the third height of the immersion tank having substantially the first height of the canister, the immersion tank being placed at a dry preparation area for draining and drying the transfer cask and canister, the immersion tank being operative to receive the transfer cask and canister from the spent fuel pool and circulate fluid about the transfer cask and canister, thereby cooling and providing shielding for the received transfer cask containing the spent nuclear fuel during the process of draining and drying the transfer cask and canister, the third sidewall of the immersion tank being spaced apart from the second sidewall of the transfer cask to permit convective flow of fluid within the immersion tank.

2. The system of claim 1, further comprising a canister that is loaded with spent nuclear fuel and is located in the transfer cask.

3. The system of claim 2, wherein the transfer cask includes a sidewall and a top wall, the sidewall and the top wall being spaced apart from the sidewall and top wall of the canister, respectively, to permit convective flow of fluid within the transfer cask.

4. The system of claim 3, wherein the transfer cask includes a low flow resistance inlet and outlet to facilitate removal of heat from the canister, the inlet being located adjacent to the bottom portion of the sidewall of the transfer cask, the outlet being located adjacent to the top portion of the sidewall of the transfer cask.

5. The system of claim 4, wherein the low flow resistance inlet and outlet include slots through the sidewall of the transfer cask to permit intake or outtake of fluid for the transfer cask

6. The system of claim 4, wherein the slot of the inlet being slanted upwards from the inner surface to the outer surface of the sidewall of the transfer cask, the slot of the outlet being slanted downwards from the inner surface to the outer surface of the sidewall of the transfer cask

7. The system of claim 1, further comprising a pump that pumps the fluid into the immersion tank where the fluid circulates within the transfer cask.

8. The system of claim 7, further comprising a heat exchanger that cools the fluid before the fluid is pumped into the immersion tank.

9. The system of claim 7, further comprising a cleaning system that cleans the fluid before the fluid is pumped into the immersion tank.

10. The system of claim 7, wherein the fluid in the immersion tank circulates in a closed loop.

11. The system of claim 1, further comprising a transfer adapter that is used to transfer the canister along with the spent nuclear fuel into a storage cask.

12. The system of claim 1, wherein the transfer cask comprises lifting trunnions that are attached to the sidewall of the transfer cask adjacent to the top portion of the transfer cask to facilitate transferring the transfer cask into the immersion tank.

13. The system of claim 1, further comprising a fluid jacket covering the canister while the canister is in the immersion tank.

14. The system of claim 1, further comprising:

means for circulating the fluid within the immersion tank;

means for cooling the fluid before the fluid is pumped into the immersion tank; and

means for cleaning the fluid before the fluid is pumped into the immersion tank.

15-19. -19. (canceled)

20. A system for loading and transferring spent nuclear fuel, comprising:

a transfer cask having a first sidewall that has a first height, the transfer cask being operative to contain spent nuclear fuel and to shield radioactivity of the spent nuclear fuel, the transfer cask that contains the canister being operative to be placed in a spent fuel pool, the spent fuel pool having a depth that is at least twice the height of the canister and transfer cask;

an immersion tank having a second sidewall that has a second height, the second height of the immersion tank having substantially the first height of the transfer cask, the immersion tank being placed at a dry preparation area for draining and drying the transfer cask and canister, the immersion tank being operative to receive the transfer cask and canister from the spent fuel pool and provide shielding for the received transfer cask containing the spent nuclear fuel during the process of draining and drying the transfer cask and canister, the second sidewall of the immersion tank being spaced apart from the second sidewall of the transfer cask to permit convective flow of fluid within the immersion tank;

a pump operative to pump fluid into the immersion tank and circulate the fluid within the transfer cask and in the immersion tank in a closed loop;

a heat exchanger operative to receive and cool the fluid before the fluid is pumped into the immersion tank; and

a cleaning system operative to receive and cleans the fluid before the fluid is pumped into the immersion tank.

21. An immersion tank that is placed at a dry preparation area for draining and drying the transfer cask and canister, comprising:

a bottom wall; and

a first sidewall that is attached to the bottom wall, the first sidewall having a first height, the first height of the immersion tank having substantially a second height of a second sidewall of a transfer cask, the transfer cask being operative to be placed in a spent fuel pool, the spent fuel pool having a depth that is at least twice the height of the canister and transfer cask, the first sidewall of the immersion tank being spaced apart from the second sidewall of the transfer cask to receive the transfer cask from the spent fuel pool, provide shielding for the received transfer cask containing the spent nuclear fuel, and permit convective flow of fluid within the immersion tank during the process of draining and drying the transfer cask and canister.

22. The immersion tank as defined in claim 21, further comprising a pump that is coupled to the first sidewall of the immersion tank, the pump being operative to pump fluid into the immersion tank and circulate the fluid within the transfer cask and in the immersion tank in a closed loop.

23. The immersion tank as defined in claim 22, further comprising a heat exchanger that is coupled to the first sidewall of the immersion tank, the heat exchanger being operative to receive and cool the fluid before the fluid is pumped into the immersion tank.

24. The immersion tank as defined in claim 23, further comprising a cleaning system operative to receive from the heat exchanger and clean the fluid before the fluid is pumped into the immersion tank.