SUBMERGED CONTAINMENT VESSEL FOR A NUCLEAR REACTOR

• US 20090129531A1
• Filed: 11/15/2007
• Published: 05/21/2009
• Est. Priority Date: 11/15/2007
• Status: Active Grant

• Current Assignee: NuScale Power, LLC.
• Original Assignee: Oregon State University (Oregon University System)
• Inventors: Groome, John T., Reyes, Jose N. JR.
• Granted Patent: US 8,687,759 B2
• Time in Patent Office: Days
• US Class Current: 376/299
• CPC Class Codes: G21C 1/322 wherein the heat exchanger is disposed above the core
• CPC Class Codes: G21C 13/022 Ventilating arrangements
• CPC Class Codes: G21C 13/024 Supporting constructions for pressure vessels or containment vessels
• CPC Class Codes: G21C 15/18 Emergency cooling arrangements; Removing shut-down heat
• CPC Class Codes: G21C 9/012 by thermal accumulation or by steam condensation, e.g. ice condensers
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A power module assembly includes a reactor core immersed in a coolant and a reactor vessel housing the coolant and the reactor core. An internal dry containment vessel submerged in liquid substantially surrounds the reactor vessel in a gaseous environment. During an over-pressurization event the reactor vessel is configured to release the coolant into the containment vessel and remove a decay heat of the reactor core through condensation of the coolant on an inner surface of the containment vessel.

Claims

1. A power module assembly comprising:

reactor core immersed in a primary coolant;

a reactor vessel housing the primary coolant and the reactor core; and

an internal dry containment vessel in direct contact with and completely submerged in liquid, wherein the containment vessel substantially surrounds the reactor vessel in a gaseous environment, wherein the containment vessel is designed to prohibit a release of the primary coolant out of the containment vessel, and wherein all of the primary coolant contained in the containment vessel is housed in the reactor vessel.

2. The power module assembly according to claim 33, further comprising a flow limiter mounted on the reactor vessel for venting the primary coolant as steam that condenses on the inner surface of the containment vessel.

3. The power module assembly according to claim 1 wherein the containment vessel is arranged to float in the liquid.

4. The power module assembly according to claim 33, further comprising a flow limiter connected to the reactor vessel that vents the primary coolant at a rate that maintains a steady state containment pressure through condensation of the primary coolant on the inner surface of the containment vessel.

5. The power module assembly according to claim 33 wherein an inner surface of the containment vessel is dry prior to the over-pressurization event.

6. The power module assembly according to claim 33, further comprising cooling fins attached to an outside wall of the containment vessel and within the liquid to further remove the decay heat of the reactor core, wherein the condensation on the inner surface occurs on a portion of the containment wall opposite the cooling fins.

7. The power module assembly according to claim 33 wherein the primary coolant remains confined within the containment vessel during the over-pressurization event.

8. The power module assembly according to claim 33 wherein the gaseous environment is maintained at below atmospheric pressure during normal operation of the power module assembly, and wherein the gaseous environment is maintained at an above atmospheric pressure condition after the primary coolant is released into the containment vessel.

33. The power module assembly according to claim 1 wherein during an over-pressurization event the reactor vessel releases the primary coolant into the containment vessel and removes a decay heat of the reactor core through condensation of the primary coolant on an inner surface of the containment vessel located adjacent the liquid.

34. The power module assembly according to claim 33 wherein the primary coolant that condenses in the containment vessel is circulated back through the reactor core without leaving the containment vessel.

35. The power module assembly according to claim 33 wherein a pool of the condensed primary coolant forms in the containment vessel and surrounds a lower portion of the reactor vessel.

36. The power module assembly according to claim 35 wherein the pool of primary coolant in the containment vessel did not exist prior to the over-pressurization event.

37. The power module assembly according to claim 1 wherein substantially the entire outer surface of the containment vessel is in direct contact with the liquid.

9-20. -20. (canceled)

21. A power module comprising:

a containment vessel in contact with and substantially submerged in a liquid, wherein the containment vessel is designed to prohibit a release of a primary coolant out of the containment vessel and into the liquid;

a reactor vessel mounted inside the containment vessel;

a reactor core submerged in the primary coolant, wherein during normal operation of the power module, all of the primary coolant contained in the containment vessel is housed within the reactor vessel; and

a steam vent connected to the reactor vessel, wherein when the reactor core becomes over-heated the steam vent controllably releases the primary coolant as steam into the containment vessel, wherein the steam condenses on an inner surface of the containment vessel and forms a pool of primary coolant extending between the inner surface of the containment vessel and an outer surface of the reactor vessel and wherein the entire inner surface of the containment vessel is dry during the normal operation of the power module and prior to the steam being vented into the containment vessel.

22. The power module according to claim 21 wherein the condensation of the steam on the inner surface of the containment vessel reduces pressure in the containment vessel at approximately the same rate that the vented steam adds pressure to the containment vessel.

23. The power module according to claim 21 wherein the steam is released into the containment vessel to remove a decay heat of the reactor core through condensation of the steam on the inner surface of the containment vessel, and wherein the decay heat is removed by the liquid located opposite the condensed steam on an outer surface of the containment vessel.

24. The power module according to claim 21 wherein heat from the power module is removed primarily through conduction from an outer surface of the containment vessel.

25. The power module according to claim 21 wherein the inner surface of the containment vessel is maintained at a below atmospheric pressure condition during normal operation of the power module, and wherein the gaseous environment is maintained at an above atmospheric pressure condition after the primary coolant is released into the containment vessel.

29. The power module according to claim 21 wherein the steam vent controllably releases steam into the containment vessel when a pressure within the reactor vessel exceeds a maximum pressure threshold value.

30. The power module assembly according to claim 21 wherein the pool of primary coolant fills the containment vessel outside of the reactor vessel to a level that is greater than a top of the reactor core.

31. The power module assembly according to claim 30 wherein the level of the pool of primary coolant outside of the reactor vessel maintained at approximately the same level as the primary coolant that remains within the reactor vessel.

32. The power module assembly according to claim 21 wherein the pool of primary coolant within the containment vessel is comprised entirely of primary coolant that is released from the reactor vessel.

26-28. -28. (canceled)

38. A method, comprising:

cooling a reactor core by circulating primary coolant through the reactor core, wherein the reactor core and the primary coolant are housed in a reactor vessel;

identifying a high pressure condition within the reactor vessel;

controllably releasing the primary coolant as steam into a containment vessel substantially surrounding the reactor vessel, wherein the entire inner surface of the containment vessel is dry prior to releasing the primary coolant as steam into the containment vessel;

condensing the steam on the inner surface of the containment vessel, wherein the condensed steam forms a pool of primary coolant extending between an outer wall of the reactor vessel and the inner surface of the containment vessel; and

circulating the pool of primary coolant back into the reactor vessel and through the reactor core, wherein the pool of primary coolant is made up entirely of the condensed steam.

39. The method according to claim 38 wherein the containment vessel is completely submerged in water.

40. The method according to claim 38 wherein a surface level of the pool of primary coolant is higher than the top of the reactor core, and wherein the pool of primary coolant did not exist prior to releasing the primary coolant as steam into the containment vessel.