STEAM SEPARATOR, BOILING WATER REACTOR AND SWIRLER ASSEMBLY

Abstract

A steam separator comprises an outer main swirler and an inner auxiliary swirler which is smaller than the main swirler. The swirlers are provided so as to be concentric on the inner wall at the lower side of the first stage inner cylinder. In the steam separator, when the gas-liquid two-phase flow which flows in the vicinity of the axial center of the first stage inner cylinder passes the auxiliary swirler, it is separated into steam and water by the centrifugal force. The separated water (droplets) is introduced into the main swirler. When the separated water (droplets) passes the main swirler, it is separated at the inner wall side of the first stage inner cylinder by the centrifugal force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view showing the structure of the steam separator according to an embodiment of the present invention.

FIG. 2 a is a cross sectional view showing a first stage inner cylinder shown in FIG. 1.

FIG. 2 b is a longitudinal sectional view showing the first stage inner cylinder including a main swirler and an auxiliary swirler shown in FIG. 1.

FIG. 2 c is a structural view showing the first stage inner cylinder in the state that is viewed from the lower side.

FIG. 2 d is a pattern diagram showing the mounting structure for the auxiliary swirler shown in FIG. 2a.

FIG. 3 a is a cross sectional view showing another embodiment of a first stage inner cylinder.

FIG. 3 b is a pattern diagram showing the mounting structure for the auxiliary swirler shown in FIG. 3a.

FIG. 4 a is a cross sectional view showing another embodiment of a first stage inner cylinder.

FIG. 4 b is a pattern diagram showing the mounting structure for the auxiliary swirler shown in FIG. 4a.

FIG. 5 a is a structural view showing an auxiliary swirler having two auxiliary swirl blades in the state that is viewed from the lower side.

FIG. 5 b is a sectional view from a line L-L shown in FIG. 5a.

FIG. 5 c is a sectional view from a line M-M shown in FIG. 5a.

FIG. 6 a is a structural view showing another embodiment of an auxiliary swirler having one auxiliary swirl blade in the state that is viewed from the lower side.

FIG. 6 b is a sectional view taken along a line O-O shown in FIG. 5a.

FIG. 7 a is a structural view showing another embodiment of an auxiliary swirler having one auxiliary swirl blade in the state that is viewed from the lower side.

FIG. 7 b is a sectional view taken along a line P-P shown in FIG. 7a.

FIG. 8 a is a pattern drawing showing an example of steam flow and droplet flow in the auxiliary swirler which is viewed from below.

FIG. 8 b is a pattern drawing showing an example of the steam flow and the droplet flow in a longitudinal section of the auxiliary swirler.

FIG. 9 is a structural view showing an example of a swirler assembly.

FIG. 10 is a structural view showing another example of the swirler assembly.

FIG. 11 a is a structural view showing modified example of the steam separator.

FIG. 11 b is a structural view showing another modified example of the steam separator.

FIG. 12 is a structural view showing a forced circulation BWR that is equipped with the steam separator shown in FIG. 1.

FIG. 13 is a structural view showing a natural circulation BWR that is equipped with the steam separator shown in FIG. 1.

Claims

1. A steam separator for separating gas-liquid two-phase flow into liquid and gas, said steam separator comprising: a stand-pipe for introducing said gas-liquid two-phase flow from an lower potion thereof to an upper portion thereof;a diffuser for forming a flow path which connects to an upper end portion of said stand pipe and expands the flow path area toward the upward direction so as to be greater than that at an upper end of said stand-pipe;a fist stage inner cylinder for forming a flow path being connected to an upper end portion of said diffuser;a first stage outer cylinder for forming a annular space which encloses said first stage inner cylinder;a first stage annular plate for sealing an inner peripheral edge of an upper end of said first stage outer cylinder and forming a circular hole with a diameter smaller than an inner diameter of said first stage inner cylinder;a first stage pick-off ring which stands upright in a cylindrical shape from an inner peripheral edge which forms a circular hole on said first stage annular plate, and forms a flow path which passes through said circular hole;a main swirler including a first hub disposed at an axial center thereof, a plurality of main swirl blades mounted radially around said first hub; anda auxiliary swirler being shorter in the transverse direction than an radius at position being mounted on inner surface of said diffuser or said first stage inner cylinder, and having an auxiliary swirl blade mounted around a second hub connected to said first hub,wherein an outer edge of said main swirl blades are fixed to an inner wall of said diffuser or to an inner wall of a lower portion of said first stage inner cylinder, a main swirl flow path is formed in the space formed with said inner wall, said first hub and said main swirl blades, each lower end of said auxiliary swirl blades is positioned lower than an upper end of said main swirl blade, and an auxiliary swirl flow path is formed in the space along said auxiliary swirl blades formed of said second hub and said auxiliary swirl blades.

2. The steam separator according to claim 1, wherein a notch portion at the lower inner side of each of said main swirl blades is formed, said second hub is a portion of said first hub, and a number of auxiliary swirl blades mounted around the second hub is less than a number of said main swirl blades.

3. The steam separator according to claim 1, wherein said first hub is formed in a cylindrical configuration, a notch portion is formed at the inner side of each of said main swirl blade in the hollow of said first hub, said auxiliary swirler is disposed in a space formed by said notch portion, and said auxiliary swirl blades and said main swirl blades are connected.

4. The steam separator according to claim 1, wherein an outer diameter of said auxiliary swirler is smaller than an inner diameter of said stand-pipe.

5. The steam separator according to claim 1, wherein a number of said auxiliary swirl blades is at least one, and a number of said auxiliary swirl blades is less than that of said main swirl blades.

6. The steam separator according to claim 1, wherein incline slits inclined in a direction opposite to a incline direction of said main swirl blades are formed at an upper portion of said first stage inner cylinder.

7. The steam separator according to claim 1, wherein an opening is formed in said first stage annular plate, and a discharge pipe is provided to said first stage annular plate and stands upright in the opening toward an upper direction.

8. The steam separator according to claim 1, wherein when said first stage outer cylinder has a length which also encloses said diffuser, and an outer diameter of said first stage outer cylinder at a lower portion which is positioned lower than said diffuser is smaller than an outer diameter of said first stage outer cylinder at an upper portion side which is positioned upper than that.

9. The steam separator according to claim 1, comprising: an another stage inner cylinder for forming the flow path for the gas-liquid two-phase flow;an another stage outer cylinder enclosing said another stage inner cylinder so as to be a concentric with a space between;an another stage annular plate for sealing an inner peripheral edge of an upper end of said another stage outer cylinder and forming an another stage circular hole whose diameter is smaller than an inner diameter of said another stage inner cylinder; andan another stage pick-off ring having a cylindrical portion which extends toward lower direction from said another stage circular hole and forming a flow path which passes through said another stage circular hole,wherein a first stage steam separation section includes said diffuser, said fist stage inner cylinder, said first stage outer cylinder, said first stage circular plate, said first stage pick-off ring, said main swirler and said auxiliary swirler,an another stage steam separation section includes said another stage inner cylinder, said another stage annular plate, and said another stage pick-off ring,and at least one stage of said another stage steam separation section is layered on said first stage steam separation section and connected to said first stage steam separation section as a flow path is formed.

10. A boiling water reactor comprising: a reactor pressure vessel;a core disposed in said reactor pressure vessel; and a plurality of steam separators according to claim 1 which is arranged above said core in said reactor pressure vessel.

11. A swirler assembly for being incorporated into a steam separator which separates gas-liquid two-phase flow into liquid and gas, comprising: a short cylinder;a main swirler including a first hub disposed at an axial center thereof, a plurality of main swirl blades mounted radially around said first hub; anda auxiliary swirler being shorter in the transverse direction than an radius at position being mounted on inner surface of said short cylinder, and having an auxiliary swirl blade mounted around a second hub connected to said first hub,wherein an outer edge of said main swirl blades are fixed to an inner wall of said short cylinder, a main swirl flow path is formed in the space formed with said inner wall, said first hub and said main swirl blades, each lower end of said auxiliary swirl blades is positioned lower than an upper end of said main swirl blade, and an auxiliary swirl flow path is formed in the space along said auxiliary swirl blades formed of said second hub and said auxiliary swirl blades.