Radioactive capture system for severe accident containment of light water reactors (LWRS), and method thereof

Patent metadata

Field	Value
Publication number	US-9406407-B2
Application number	US-201213710766-A
Country	US
Kind code	B2
Filing date	Dec 11, 2012
Priority date	Dec 11, 2012
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A system and a method for capturing gaseous, particulate and liquid radioactive material released from primary containment of a Light Water Reactor (LWR) during severe accident conditions. The system includes a below-grade media area, connected to a reactor pressure vessel (RPV) and portions of primary containment, providing varying levels of adsorption/absorption of the radioactive material. The media area is located on-site to offer a passive, self-regulating structure for stabilizing a nuclear reactor. The capture system provides for liquid drainage and gaseous venting of the radioactive material, and a treatment capable of treating the media following stabilization of the reactor.

First claim

What is claimed is:

1. A capture system, comprising:
a media area located below-grade and near a primary containment structure of a nuclear reactor;
granular media within the media area;
discharge piping configured to fluidly connect the media area to the primary containment structure, a distal end of the discharge piping being located in the media area; and
a gas outlet pipe coupled to the media area,
wherein the granular media has a granular size, the granular size of the granular media decreasing between the distal end of the discharge piping and the gas outlet pipe.

2. The capture system of claim 1 , wherein the granular media includes at least one of rock, sand, resin, silica, beads, stones and activated alumina.

3. The capture system of claim 1 , wherein walls of the media area include at least one of natural geological media, a rubber liner, plastic, sand, concrete, rebar reinforced concrete, and steel.

4. The capture system of claim 3 , further comprising:
baffles connected to the walls of the media area.

5. The capture system of claim 4 , wherein the baffles include at least one of transverse and longitudinal baffles.

6. The capture system of claim 5 , wherein the longitudinal baffles are sloped relative to a plane that is about perpendicular to the direction of gravity.

7. The capture system of claim 1 , wherein a bottom surface of the media area is sloped relative to a plane that is about perpendicular to the direction of gravity.

8. The capture system of claim 1 , further comprising:
a valve in the discharge piping.

9. The capture system of claim 1 , further comprising:
a liquid outlet pipe fluidly coupled to a bottom portion of the media area, the liquid outlet pipe extending below the media area.

10. The capture system of claim 1 , wherein,
the gas outlet pipe is fluidly coupled to a top portion of the media area,
the gas outlet pipe extends above-grade.

11. The capture system of claim 10 , further comprising:
a venting system, located above grade and connected to a distal end of the gas outlet pipe.

12. The capture system of claim 11 , wherein the venting system includes at least one of a safety relief valve, a rupture disc and a bursting disc.

13. The capture system of claim 12 , wherein the venting system further includes a vent valve.

14. The capture system of claim 10 , further comprising:
a gas space area located in the media area, the gas outlet pipe being fluidly connected to the gas space area.

15. The capture system of claim 10 , further comprising:
a lower discharge pipe in the media area and connected to the distal end of the discharge pipe;
an upper gas outlet pipe in the media area and connected to the gas outlet pipe, the upper gas outlet pipe being located along the top portion of the media area;
a flow path defined by the media area, the flow path existing between the lower discharge pipe and the upper gas outlet pipe and configured to convey radioactive material between the lower discharge pipe and the upper gas outlet pipe.

16. The capture system of claim 15 , further comprising:
the radioactive material, wherein the radioactive material includes at least one of gas, liquid and particulate material.

17. The capture system of claim 15 , wherein the granular size of the granular media decreases along the flow path from the lower discharge pipe to the upper gas outlet pipe.

18. The capture system of claim 15 , further comprising:
holes being defined in lower surfaces of the upper gas outlet pipe and lower and upper surfaces of the lower discharge pipe,
the upper gas outlet pipe running horizontally along the top portion of the media area,
the lower discharge pipe running horizontally along a bottom portion of the media area.

19. The capture system of claim 5 , wherein the baffles define baffle cells, the capture system further comprising:
drainage connections along a bottom surface of baffle cells located at a lower elevation of the media area.

20. The capture system of claim 9 , further comprising:
a sloped drain located below the media area and fluidly coupled to the liquid outlet pipe; and
a drum located below the sloped drain and fluidly coupled to the sloped drain.

21. The capture system of claim 10 , wherein the media area includes two or more metal tanks, the capture system further comprising:
an inlet connection on each metal tanks;
first manifold piping connecting the inlet connections to the discharge piping; and
an outlet connection on each metal tank, the outlet connections being connected to the gas outlet pipe; and
second manifold piping connecting the outlet connections to the gas outlet pipe.

22. The capture system of claim 21 , further comprising:
hydrogen recombiners located near a top portion of each of the metal tanks.

23. The capture system of claim 1 , further comprising:
a hydrogen mitigation device in the discharge piping and located above grade, the hydrogen mitigation device including at least one of an igniter and a passive autolytic recombiner.

24. The capture system of claim 1 , further comprising:
a treatment system located above grade and positioned above the media area, the treatment system being a pump-and-treat system.

25. The capture system of claim 24 , further comprising:
a treatment media within the treatment system, the treatment media including at least one of activated alumina and humate.

26. A method of capturing radioactive material with the capture system of claim 1 , comprising: transferring radioactive material from the primary containment structure to the media area.

27. The capture system of claim 3 , further comprising:
baffles connected to the walls of the media area and being configured to define a tortuous flow path through the media area, the capture system being configured to convey radioactive material from the primary containment structure through the tortuous flow path within the media area.

28. The capture system of claim 27 , wherein the baffles include at least one of transverse and longitudinal baffles.

29. The capture system of claim 27 , further comprising:
the radioactive material, wherein the radioactive material includes at least one of gas, liquid and particulate material.

30. The capture system of claim 27 , wherein the granular size of the granular media decreases along the tortuous path.

31. The capture system of claim 27 , wherein the baffles are configured to define the tortuous path such that at least a portion of the radioactive material travels in a first vector direction and a second vector direction through the tortuous path, the first vector direction being about 180 degrees from the second vector direction.

32. The capture system of claim 27 , wherein the baffles are configured to define the tortuous path such that at least a portion of the radioactive material is re-directed at least once while being conveyed through the tortuous path, a re-direction angle of the re-directed radioactive material being about 180 degrees.

33. The capture system of claim 27 , wherein the baffles are configured to define the tortuous path such that at least a portion of the radioactive material is re-directed a plurality of times while being conveyed through the tortuous path, a re-direction angle of each o

Assignees

• Loewen Eric P
• Caro Jose Maria
• Bass Derek
• Ge Hitachi Nuclear Energy Americas Llc

Inventors

• Loewen Eric P
• Caro Jose Maria
• Bass Derek

Classifications

• G21C9/00 Primary

  Emergency protection arrangements structurally associated with the reactor {, e.g. safety valves provided with pressure equalisation devices}(emergency cooling arrangements G21C15/18) · CPC title

• G21C13/10

  Means for preventing contamination in the event of leakage, {e.g. double wall} · CPC title

• G21D1/00

  Details of nuclear power plant (control G21D3/00) · CPC title

• Y02E30/40

  Cross-Sectional Technologies · mapped topic

• G21C9/001 Primary

  against explosions, e.g. blast shields · CPC title