JP2001083276A - Steam/water separator and boiling water reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce carryover from a control drive shaft guide tube penetrating through a steam/water separator 20 and suppress the vibration of the control rod drive shaft in a boiling water reactor inserted by control rods from above the upper core. SOLUTION: A steam/water separator 20 consists of separator bodies 21, 22 and 23 and the separator bodies 21, 22 and 23 are constituted in dual cylinder provided with outer cylinders 21A, 22A and 23A and inner cylinders 21B, 22B and 23B. In the lower part of the inner cylinder 21B, a swirl vane 24 is provided and swirl is generated in the steam-water two-phase flow 34 flowing in the inner cylinder 21B. In such a steam/water separator, a control rod drive shaft guide tube 28 penetrates the steam/water separator 20 in the control rod drive shaft guide tube 28, a hole 29 is formed above the swirl vane 24. As the hole 29 is formed, the steam-water two-phase flow 34 in the control rod drive shaft guide tube 28 is exhausted by way of the hole 29 and leak 37 at connection part 31 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a steam-water separator installed in a boiling water reactor, and to a boiling water reactor.

[0002]

2. Description of the Related Art In order to improve the economic efficiency of a boiling water reactor, it is necessary to increase the power density. In order to increase the power density, a large bundle core has recently been proposed in which a water region outside the channel box and serving as a neutron moderator is taken into a fuel assembly. In the core of the large bundle,
When a cross-shaped control rod is used, a cluster-type control rod is required because there is a limit in a reactor shutdown margin.

In the case of a cluster-type control rod, a method of inserting the control rod from the upper part of the core is necessary because of the reliability of the control rod insertion when the reactor is stopped. There is a risk of interfering with the steam-water separator and steam dryer at the top, and avoiding this interference has been a challenge.

In order to solve the above problem, for example, Japanese Patent Application Laid-Open No.
Japanese Patent Publication No. 30078 proposes a boiling water reactor as shown in the sectional view of FIG. In this boiling water reactor, the control rod 1 is of a cluster type and is inserted from above the reactor core 2. A control rod drive mechanism 3 for driving the control rod 1 penetrates the upper lid of the shroud head 4 and the upper plenum structure 5, and further passes through a control rod drive mechanism housing 7 fixed to the pressure vessel upper lid 6. Connected to an external drive. A steam-water separator 10 fixed to the upper part of the shroud head 4 via a stand pipe 9 is annularly disposed around the control rod drive mechanism 3. A steam dryer 11 is provided above the steam separator 10, and the steam dryer 11 is also annularly disposed around the control rod drive mechanism 3.

Japanese Patent Application Laid-Open No. Sho 62-197794 discloses that a control rod drive shaft is made to pass through a steam / water separator disposed in a shroud head above a reactor core, and a steam dryer is provided with a control rod drive shaft. An annular arrangement at the periphery has been proposed.

Further, in Japanese Patent Application Laid-Open No. 62-67489, similarly to the above-mentioned publication, the control rod drive shaft is passed through a steam-water separator arranged in a shroud head above the core, and the steam dryer is It has been proposed that the control rod drive shaft be arranged annularly around the control rod drive shaft, and further provided with a protrusion on the control rod drive shaft in order to scatter droplets attached to the control rod drive shaft in the steam separator. I have.

[0007]

According to Japanese Patent Laid-Open Publication No. Sho 61-230078, the control rod drive mechanism 3 penetrates the shroud head 4 and the upper lid of the upper plenum structure 5 as shown in FIG. It has a structure. This publication does not specify whether the control rod drive mechanism 3 is a control rod drive shaft or whether the control rod drive shaft is inserted into the control rod drive shaft guide tube. If the control rod drive mechanism 3 has only the control rod drive shaft, the gas-liquid two-phase flow 12 and the wet steam 13 do not leak through the penetrating portion where the control rod drive shaft passes through the shroud head 4 and the upper lid of the upper plenum structure 5. It is necessary to have a seal structure. However, since the control rod drive shaft is for inserting or removing the control rod 1 and moves in the vertical direction,
It is impossible to eliminate the leakage from the penetration.

On the other hand, when the control rod drive mechanism 3 comprises a control rod drive shaft and a control rod drive shaft guide tube, that is, when the control rod drive shaft is inserted inside the control rod drive shaft guide tube,
If the control rod drive shaft guide tube penetrates the upper lid of the shroud head 4 and the upper plenum structure 5 by welding or sealing, it is possible to eliminate leakage. However, at the time of refueling, the control rod drive shaft guide tube must be cut off from the control rod drive mechanism housing 7 fixed to the pressure vessel upper lid 6, so that the connecting portions 14 of the two have a fitting structure with a gap. Gas-liquid two-phase flow that has risen in the control rod drive shaft guide tube leaks out of the connection portion 14,
There is a drawback that the moisture of the dry steam 15 downstream of the steam dryer 11 is increased to increase carryover.

Also, in Japanese Patent Application Laid-Open Nos. 62-197794 and 62-67489, since the control rod drive shaft passes through the upper lid of the upper plenum structure, wet steam from the steam separator is penetrated. However, considering that the control rod drive shaft moves in the vertical direction, it is impossible to eliminate any leakage. Furthermore, in the case of Japanese Patent Application Laid-Open No. 62-197794, the control rod drive shaft penetrating the stand pipe and the steam separator is exposed to the flow. There is. In addition, Japanese Unexamined Patent Publication
In the case of Japanese Patent Application Laid-Open No. 2-67489, a protrusion is provided on the control rod drive shaft at an interval equal to the length of the boss of the swirl vane in the steam separator and large enough to pass through a hole formed in the boss. Therefore, measures have been taken to suppress the vibration of the control rod drive shaft due to the fluid force. However, the operability when the control rod drive shaft is moved up and down may be deteriorated due to the protrusion.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a steam-water separator which reduces carryover by reducing gas-liquid two-phase flow and leakage of wet steam and suppresses vibration of a control rod drive shaft, and a boiling water atom. To provide a furnace.

[0011]

SUMMARY OF THE INVENTION To achieve the above object, the present invention is directed to a method for installing a gas-liquid two-phase flow generated in the core of a boiling water reactor, which is installed at the upper end of a cylindrical stand pipe. A multi-cylindrical member, and a swirler which is provided below the innermost cylindrical member of the multi-cylindrical member and generates a swirling flow for separating the gas-liquid two-phase flow into wet steam and separated water by centrifugal force. And discharging the wet steam from the upper portion of the multiple cylindrical member, capturing the separated water at the upper portion of the multiple cylindrical member, guiding the separated water to the outside of the innermost cylindrical member, and removing the cylindrical member outside the innermost cylindrical member. In the steam-water separator discharging through, a control rod drive shaft guide tube is provided to penetrate in the axial direction, and one or more holes are formed in the control rod drive shaft guide tube at a position above the swirler. Is characterized by being

According to the above configuration, since the control rod drive shaft guide tube has one or more holes formed above the swirler, the gas-liquid two-phase flow that has risen in the control rod drive shaft guide tube is formed. Is discharged through the hole into the cylindrical member. As a result, the pressure gradient in the control rod drive shaft guide tube is reduced at a position above the hole, and leakage from a connection portion or the like at the position above can be reduced.

A guide plate for guiding the flow of the gas-liquid two-phase flow in the control rod drive shaft guide tube to the outside of the control rod drive shaft guide tube can be provided on the lower peripheral edge of the hole. Since the liquid phase in a gas-liquid two-phase flow has the property of rising as a liquid film along the wall surface,
If an outward guide plate is provided, the liquid phase is easily discharged from the control rod drive shaft guide tube into the steam separator along the guide plate.

Further, a swirl groove for generating a swirl flow below the hole in the gas-liquid two-phase flow in the control rod drive shaft guide tube can be formed in the inner wall of the control rod drive shaft guide tube. . With this configuration, the gas-liquid two-phase flow is swirled by the swirl groove, and the liquid phase is deflected outward and the gas phase is deflected inward by centrifugal force,
When the liquid reaches the holes, the liquid phase is easily discharged.

Further, a labyrinth seal or a throttle can be formed at least at one location on the inner wall of the control rod drive shaft guide tube. When a labyrinth seal is formed, the pipe friction coefficient in the control rod drive shaft guide tube increases, and the leak flow rate decreases. Also, when a throttle is formed, the leak flow rate is reduced by the throttle.

Each of the above steam-water separators can be installed in a boiling water reactor. In such a boiling water reactor, a cluster type control rod can be inserted from the upper part of the core, so that a large bundle is used. By using the fuel assembly of (1), an economical boiling water reactor with improved power density can be obtained. That is, the present invention provides a reactor core provided in a reactor pressure vessel, a control rod drive shaft for inserting or extracting a control rod from the upper part of the reactor core with respect to the reactor core, and a gas-liquid two-phase flow generated in the reactor core. A steam-water separator for separating the wet steam and the separated water, and a wet steam separated annularly by the steam-water separator, which is annularly installed around a control rod drive shaft guide tube for guiding the control rod drive shaft. A steam dryer for drying; and a plate-shaped member provided between the steam-water separator and the steam dryer. The control rod drive shaft guide tube penetrates the plate-shaped member, and It is configured in a seal structure, and each of the steam-water separators is installed as the steam-water separator.

Further, the present invention provides a reactor core provided in a reactor pressure vessel, a control rod drive shaft for inserting or removing a control rod from above the core with respect to the reactor core, and a gas-liquid generated in the reactor core. A steam-water separator that separates the two-phase flow into wet steam and separated water, and a ring-shaped separator installed around the control rod drive shaft guide tube that guides the control rod drive shaft and separated by the steam-water separator A steam dryer for drying the wet steam, wherein a ring-shaped top plate installed at the upper end of the steam dryer is fixed to a side surface of the pressure vessel using a seal structure, and is fixed to a pressure vessel upper lid, and the control is performed. A connecting portion between the control rod drive mechanism housing for guiding the rod drive shaft and the control rod drive shaft guide tube is arranged in a region where wet steam exists upstream of the steam dryer inlet, and serves as the steam separator. And the above steam-water separators It is characterized in that the.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a longitudinal sectional view of a steam separator according to Embodiment 1 of the present invention. As shown in the figure, the steam separator 20 includes a lower separator main body 21, a middle separator main body 22,
And an upper separator main body 23. The lower separator main body 21 includes an outer cylinder 21A and an inner cylinder 21B, the middle separator main body 22 includes an outer cylinder 22A and an inner cylinder 22B, and the upper separator main body 23.
Has a double cylindrical shape provided with an outer cylinder 23A and an inner cylinder 23B. A swirler 24 is provided below the inner cylinder 21 </ b> B of the lower separator body 21, and a stand pipe 25 is attached to the swirler 24. Stand pipe 25
Is fixed to the shroud head 26 (see FIG. 2A).

A pickoff ring 21C is provided above the outer cylinder 21A of the lower separator main body 21, and an inner cylinder 22B of the middle separator main body 22 is fixed on the pickoff ring 21C. A pick-off ring 22C is provided above the outer cylinder 22A of the middle separator main body 22, and an inner cylinder 23B of the upper separator main body 23 is provided on the pick-off ring 22C.
Has been fixed. The separator body 23 is also provided with a pickoff ring 23C on the upper part of its outer cylinder 23A. The lower separator main body 21, the middle separator main body 22, and the upper separator main body 23 have an integral structure.

Lower separator main body 21, middle separator main body 2
2. A control rod drive shaft guide tube 28 for guiding the control rod drive shaft 27 is provided in the center of the upper separator main body 23, the swirler 24 and the stand pipe 25 so as to penetrate in the axial direction. A hole 29 is formed in the control rod drive shaft guide tube 28 at a position above the swirler 24, specifically, inside the lower separator main body 21. The hole 29 is formed over the entire circumference of the control rod drive shaft guide tube 28, and the control rod drive shaft guide tube 2
8 is vertically divided into two parts by holes 29.

A control rod drive mechanism housing 30 fixed to the upper lid of the pressure vessel is provided above the control rod drive shaft guide tube 28. At the lower end of the control rod drive mechanism housing 30, a connection portion 31 having a large diameter is provided.
1, the upper end of the control rod drive shaft guide tube 28 is fitted, and the control rod drive shaft guide tube 28 and the control rod drive mechanism housing 30 are connected.

A cluster-type control rod 32 is fixed to the lower end of the control rod drive shaft 27 as shown in FIG. This cluster type control rod 32 is a control rod guide tube 33.
And is moved up and down by being guided by the control rod guide tube 33.

In the above configuration, after the gas-liquid two-phase flow 34 produced in the reactor core flows into the control rod guide tube 33, most of the gas-liquid two-phase flow 34 exits through the window 33A of the control rod guide tube 33 and shrouds. It flows into the stand pipe 25 through the upper part of the head 26. The gas-liquid two-phase flow 34 that has risen in the stand pipe 25 is supplied to the swirler 2 under the lower separator main body 21.
4 separates into wet steam 35 and separated water 36 under centrifugal force. The separated water 36 becomes a liquid film and rises along the inner wall surface of the inner cylinder 21B, is captured by the upper pick-off ring 21C, flows down the gap between the outer cylinder 21A and the inner cylinder 21B, and flows down. 21 from below.

The wet steam 35 rises inside the inner cylinder 21B, flows through the pickoff ring 21C into the middle separator main body 22, further flows through the pickoff ring 22C into the upper separator main body 23, and the separated water is removed. After being almost separated, it is discharged from the upper part of the upper separator main body 23.

On the other hand, a slight gas-liquid two-phase flow 34 also rises in the control rod drive shaft guide tube 28. This gas-liquid two-phase flow 34
Most of the holes 29 are formed in the control rod drive shaft guide tube 28.
Is discharged into the inner cylinder 21B of the lower separator body 21.

FIG. 2B shows the inside of the stand pipe 25 and the steam separator 20 from the control rod guide pipe 33 to the connection 31 between the control rod drive shaft guide pipe 28 and the control rod drive mechanism housing 30. The pressure distribution in the rod drive shaft guide tube 28 is shown. The pressure loss in the standpipe 25 and the steam separator 20 is almost generated at the inlet of the standpipe 25 and the swirl vane 24, and has substantially the same magnitude. on the other hand,
Regarding the flow in the control rod drive shaft guide tube 28, the connection portion 3
If there is no hole other than 1, the control rod drive shaft guide tube 2
Since the gap between the shaft 8 and the control rod drive shaft 27 is small, the pressure loss is almost entirely caused by pipe friction, and the pressure decreases linearly in proportion to the distance. Then, the mass flow rate of the gas-liquid two-phase flow 34 flowing in the control rod drive shaft guide tube 28, that is, the connection portion 31
Is the leak mass flow rate W of the gas-liquid two-phase flow from the following equation (1).

[0027]

(Equation 1)

Here, A is the flow path cross-sectional area of the gap between the control rod drive shaft guide tube 28 and the control rod drive shaft 27, D is the hydraulic equivalent diameter of the gap, ρ is the liquid phase density, and λ is the pipe friction coefficient. , ΔP is the pressure loss, and L is the distance at which the pressure loss ΔP occurs. Also,
φ is the multiplication factor of the two-phase flow with respect to the pressure loss of the liquid phase,
It is a coefficient given by the density and quality of the gas and liquid phases.

Although the leak mass flow rate W from the connection portion 31 is negligible compared to the mass flow rate flowing into the steam separator 20, since the outlet of the steam separator 20 is wet steam,
Carryover results in non-negligible moisture.

Therefore, in order to reduce the carryover, it is necessary to reduce the leak 37 of the gas-liquid two-phase flow from the connection part 31. According to Equation 1, if the pressure gradient (ΔP / L) is reduced, the leak mass flow rate W from the connection portion 31 can be reduced. In the present embodiment, a hole 29 through which a gas-liquid two-phase flow flows out is provided in a part of the control rod drive shaft guide tube 28 to reduce the pressure gradient (ΔP / L). Since the flow rate of the gas-liquid two-phase flow flowing in the control rod drive shaft guide tube 28 is negligible compared to the main flow, when the holes 29 are provided, the pressure distribution in the control rod drive shaft guide tube 28 changes, The pressure distribution in the water separator 20 does not change. Therefore, the pressure in the control rod drive shaft guide tube 28 at the position where the hole 29 is provided gradually approaches the pressure in the steam separator 20 as the area of the hole 29 increases.

By providing the hole 29 above the swirler 24 in this manner, the pressure gradient (ΔP /
L) can be reduced, and the leak flow rate from the connection portion 31 can be reduced. Here, the pressure gradient (ΔP / L) on the upstream side of the hole 29 increases, but an amount larger than the flow rate downstream of the hole 29 is discharged from the hole 29 into the inner cylinder 21 </ b> B of the lower separator main body 21. . The gas-liquid two-phase flow 34 discharged from the hole 29 is separated into separated water 36 and wet steam 35 by the swirl flow generated by the swirler 24. In consideration of the gas-liquid separation efficiency of the gas-liquid two-phase flow 34 discharged from the hole 29, it is desirable to form the hole 29 in the vicinity of the swirler 24 having a strong swirl flow. Further, as the area and the number of the holes 29 are larger, the pressure distribution in the control rod drive shaft guide tube 28 gradually approaches the pressure in the steam separator 20, so that the leak flow rate also decreases.

As a result of separation of the gas-liquid two-phase flow 34 discharged from the hole 29, separated water 36 and wet steam 35 are generated.
The separated water 36 rises along the inner wall surface of the inner cylinder 21B as a liquid film, is captured by the upper pick-off ring 21C, and is discharged from the lower part of the lower separator main body 21. Also,
The wet steam 35 flows through the pickoff ring 21C to the middle-stage separator main body 22 and the upper-stage separator main body 23, and the separated water is further separated.

According to the present embodiment, the flow rate of leakage from the connecting portion 31 is reduced, so that carryover can be reduced. Further, the control rod drive shaft 27 is housed inside the control rod drive shaft guide tube 28. In this control rod drive shaft guide tube 28, the flow of the gas-liquid two-phase flow 34 is not so strong. The shaft 27 does not vibrate, and wear of the control rod drive shaft 27 and a contact portion with the control rod drive shaft 27 can be prevented.

The lower separator main body 21, the middle separator main body 22, and the upper separator main body 23 are not limited to a double cylindrical shape, but may have a triple cylindrical shape or a quadruple or more cylindrical shape.

(Embodiment 2) FIG. 3 is a longitudinal sectional view of a main part of a steam separator according to Embodiment 2 of the present invention. In the present embodiment, the control rod drive shaft guide tube 28 is provided with a plurality of holes 40 at a position above the swirler 24. The plurality of holes 40 are circular, and the control rod drive shaft guide tube 28
Are formed in the circumferential direction and the vertical direction.

Also in this case, the gas-liquid two-phase flow 34 that has risen in the control rod drive shaft guide tube 28 is discharged from the plurality of holes 40 into the inner cylinder 21B.
Leakage 37 can be reduced.

According to the present embodiment, since the hole is not formed over the entire circumference of the control rod drive shaft guide tube 28 as in the first embodiment, the strength of the control rod drive shaft guide tube 28 is impaired. Nothing.

(Embodiment 3) FIG. 4 is a longitudinal sectional view of a main part of a steam separator according to Embodiment 3 of the present invention. In the present embodiment, a guide plate 41 is provided below hole 29 shown in the first embodiment. The guide plate 41 has a shape in which an upper peripheral edge is outwardly widened, and is formed over the entire circumference of the control rod drive shaft guide tube 28.

Generally, since the liquid phase has a property of rising along the wall surface, the liquid phase of the gas-liquid two-phase flow 34 rising in the control rod drive shaft guide tube 28 is changed to the control rod drive shaft guide tube 28.
It rises on the inner wall surface. If the guide plate 41 is provided as in the present embodiment, the liquid phase of the gas-liquid two-phase flow 34 flows on the guide plate 41, so that the liquid phase is discharged into the inner cylinder 21B of the lower separator main body 21. It is easy to be. As a result, the gas-liquid two-phase flow 34 is easily discharged into the inner cylinder 21 </ b> B of the lower separator main body 21, and the leak 37 from the connection part 31 can be reduced.

(Embodiment 4) FIG. 5 is a vertical sectional view of a main part of a steam separator according to Embodiment 4 of the present invention. In the present embodiment, the turning groove 4 is provided on the inner wall surface of the control rod drive shaft guide tube 28.
2 are formed. The turning groove 42 is formed on an inner wall surface below the hole 29 provided in the control rod drive shaft guide tube 28.

If such a turning groove 42 is formed,
When ascending in the control rod drive shaft guide tube 28, the gas-liquid two-phase flow 34 is swirled by the swirl groove 42. The liquid phase is deflected outward and the gas phase is deflected inward by the centrifugal force caused by the swirl. When the liquid phase reaches the hole 29, the gas-liquid two-phase flow 34 is easily discharged into the inner cylinder 21B of the lower separator main body 21. Therefore, the leak 37 from the connection part 31 can be reduced.

(Embodiment 5) FIG. 6 is a longitudinal sectional view of a main part of a control rod drive shaft guide tube according to Embodiment 5 of the present invention.
A feature of the present embodiment is that a labyrinth seal 43 is provided on the inner wall surface of the control rod drive shaft guide tube 28. That is, the labyrinth seal 43 is provided on the upper part of the control rod drive shaft guide tube 28 which is fitted to the connection part 31 provided in the control rod drive mechanism housing 30. The labyrinth seal 43 can be provided not only on the upper part of the control rod drive shaft guide tube 28 but also on the lower side.

By providing such a labyrinth seal 43, the pipe friction in the control rod drive shaft guide tube 28 increases, so that the leak 37 from the connecting portion 31 decreases,
Carryover can be reduced.

(Embodiment 6) FIG. 7 is a longitudinal sectional view of a main part of a control rod drive shaft guide tube according to Embodiment 6 of the present invention.
A feature of the present embodiment is that a throttle 44 is provided on the inner wall surface of the control rod drive shaft guide tube 28. That is, the throttle 44 is provided near the outlet of the control rod drive shaft guide tube 28 which is fitted to the connection portion 31 provided in the control rod drive mechanism housing 30. A plurality of such apertures 44 can be provided near the outlet and below the outlet.

By providing such an aperture 44,
Since the gas-liquid two-phase flow flowing in the control rod drive shaft guide tube 28 is reduced, the leak 37 from the connection portion 31 is reduced, and carry-over can be reduced.

(Embodiment 7) FIG. 8 shows a boiling water reactor according to Embodiment 7 of the present invention. Pressure vessel 50
Is provided with a steam dryer bottom plate 51, and a steam dryer 52 is provided on the steam dryer bottom plate 51. The steam dryer 52 is annularly arranged on the outer periphery of the control rod drive shaft guide tubes 28. A skirt portion 53 is provided on the peripheral edge of the bottom surface of the steam dryer bottom plate 51, and the skirt portion 53 is suspended below the liquid level of the coolant. The steam dryer bottom plate 51, the steam dryer 52, and the skirt 53 have an integral structure.

A plurality of steam separators 20 are provided below the steam dryer bottom plate 51, and each steam separator 20 is fixed to an upper end of a stand pipe 25 installed above the shroud head 26. A control rod drive shaft guide tube 28 having a control rod drive shaft inserted therein is provided through the center of each steam separator 20. The steam separator 20
Any of the steam separators described in Embodiments 1 to 6 is used.

The steam dryer bottom plate 51 is installed so as to cover the upper part of the steam separator 20, so that the wet steam 35 from the steam separator 20 does not reach the upper dome space 54. Further, the control rod drive shaft guide tube 28 penetrates the steam dryer bottom plate 51 and is supported by a lower end of the control rod drive mechanism housing 30 fixed to the pressure vessel upper lid 55 in a fitting structure. The lower end of the control rod drive shaft guide tube 28 is fixed to the upper end of a control rod guide tube 33 that guides the cluster type control rod. In addition, the penetration part of the steam dryer bottom plate 51 forms a seal structure.

In the above configuration, the gas-liquid two-phase flow 34 generated in the reactor core is separated into separated water and wet steam 35 by the steam separator 20, and the wet steam 35 is removed of moisture by the steam dryer 52, and dried. It becomes steam 56 and is discharged from the main steam nozzle 57 via the upper dome space 54. On the other hand, the gas-liquid two-phase flow that has risen in the control rod drive shaft guide tube 28 is discharged into the inner cylinder of the lower separator main body of the steam separator as described in each of the above embodiments. Therefore, the leak 37 from the connection portion 31 is reduced. In FIG. 8, 58 is a core, and 59 is an internal pump.

According to the boiling water reactor of the present embodiment,
Control rod drive mechanism housing 30 and control rod drive shaft guide tube 2
It is possible to reduce leakage from the connection portion 31 with the connector 8. Further, since the control rod drive shaft in the control rod drive shaft guide tube 28 is not exposed to a violent flow, the control rod drive shaft does not vibrate, and the control rod drive shaft and the contact portion with the control rod drive shaft are not affected. Can prevent wear.

Further, since the upper part of the cluster type control rod can be inserted, a highly economical boiling water reactor having an improved power density using a large bundle of fuel assemblies can be obtained.

(Eighth Embodiment) FIG. 9 shows a boiling water reactor according to an eighth embodiment of the present invention. In the present embodiment, the steam dryer bottom plate 51 as in the seventh embodiment is not provided. That is, the steam dryer 52 is supported by the annular support plate 60 fixed to the inner wall surface of the pressure vessel 50. Then, the inner wall surface of the pressure vessel 50 and the support plate 6
A cylindrical skirt portion 53 is provided on the bottom surface of the steam dryer 52 disposed annularly around the outer periphery of the control rod drive shaft guide tube 28. 53 is suspended below the liquid level of the coolant.
Other configurations are the same as those in the seventh embodiment. Also in the present embodiment, as the steam separator 20, any of the steam separators described in the first to sixth embodiments is used.

The gas-liquid two-phase flow 34 generated in the reactor core is separated into separated water and wet steam 35 by the steam separator 20, and the wet steam 3
5 is a steam dryer 52 from which moisture is removed to become dry steam 56, and the main steam nozzle 5 does not pass through the upper dome space 54.
It is discharged directly from 7. On the other hand, the control rod drive shaft guide tube 28
The gas-liquid two-phase flow that has risen inside is discharged into the inner cylinder of the lower-stage separator main body of the steam-water separator as described in each of the above-described embodiments. 37 is reduced.

According to the boiling water reactor of the present embodiment,
The same operation and effect as those of the seventh embodiment can be obtained. Also, even if moisture is discharged from the connection portion 31,
Since the upper dome space 54 in which the connecting portion 31 exists is connected to the entrance of the steam dryer 52, moisture can be removed by the steam dryer 52.

[0055]

As described above, according to the present invention,
Most of the gas-liquid two-phase flow that has risen up the control rod drive shaft guide tube is discharged into the steam separator through a hole formed in the control rod drive shaft guide tube. Leakage is reduced.

The control rod drive shaft is housed inside the control rod drive shaft guide tube. In this control rod drive shaft guide tube, the gas-liquid two-phase flow is not so intense. Vibration does not occur, and wear of the control rod drive shaft and the contact portion with the control rod drive shaft can be prevented.

Furthermore, since the upper part of the cluster type control rod can be inserted, a highly economical boiling water reactor with an improved power density using a large bundle of fuel assemblies can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a steam separator according to Embodiment 1 of the present invention.

FIG. 2A is a longitudinal sectional view of a control rod guide tube and a steam separator, and FIG. 2B is a pressure distribution diagram of the control rod guide tube and the steam separator.

FIG. 3 is a vertical sectional view of a main part of a steam separator according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a steam separator according to a third embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a main part of a steam separator according to a fourth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a main part of a control rod drive shaft guide tube according to a fifth embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a main part of a control rod drive shaft guide tube according to a sixth embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of a boiling water reactor according to a seventh embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a boiling water reactor according to an eighth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a conventional boiling water reactor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Steam separator 21C, 22C, 23C Pickoff ring 24 Revolving blade 25 Stand pipe 26 Shroud head 27 Control rod drive shaft 28 Control rod drive shaft guide tube 29 Hole 30 Control rod drive mechanism housing 31 Connection part 32 Control rod 33 Control rod Guide tube 34 Gas-liquid two-phase flow 35 Wet steam 36 Separated water 37 Leak 40 Plural holes 41 Guide plate 42 Revolving groove 43 Labyrinth seal 44 Restriction 50 Pressure vessel 51 Steam dryer bottom plate 52 Steam dryer 53 Skirt 54 Upper dome Space 55 Pressure vessel top lid 56 Dry steam 57 Main steam nozzle 58 Core 59 Internal pump 60 Support plate

Claims (7)

[Claims] 1. A multi-cylinder member installed at an upper end of a cylindrical stand pipe in which a gas-liquid two-phase flow generated in a core of a boiling water reactor rises, and an innermost cylindrical member of the multi-cylinder member. A swirler for generating a swirling flow installed at a lower portion to separate the gas-liquid two-phase flow into wet steam and separated water by centrifugal force, and discharging the wet steam from the upper portion of the multiple cylindrical member, In a steam / water separator which captures the separated water at the upper part of the multiple cylindrical member, guides the separated water to the outside of the innermost cylindrical member, and discharges the water through the cylindrical member outside the innermost cylindrical member, a control rod drive shaft guide tube Wherein the control rod drive shaft guide tube has one or more holes formed above the swirler blades. 2. The steam-water separator according to claim 1, wherein a gas-liquid two-phase flow in the control rod drive shaft guide tube is flowed out of the control rod drive shaft guide tube at a lower peripheral edge of the hole. A steam separator provided with an outward guide plate for guiding. 3. The steam / water separator according to claim 1, wherein an inner wall of the control rod drive shaft guide pipe has a gas-liquid two-phase flow in the control rod drive shaft guide pipe below the hole. A steam-water separator, wherein a swirling groove for generating a swirling flow is formed. 4. The steam-water separator according to claim 1, 2 or 3, wherein a labyrinth seal is provided on an inner wall of the control rod drive shaft guide tube. 5. The steam separator according to claim 1, wherein the control rod drive shaft guide tube has at least one throttle formed on an inner wall thereof. Separator. 6. A reactor core provided in a reactor pressure vessel,
A control rod drive shaft for inserting or removing a control rod from the upper part of the core with respect to the core, a steam-water separator for separating gas-liquid two-phase flow generated in the core into wet steam and separated water, A steam dryer for annularly disposed around a control rod drive shaft guide tube for guiding the rod drive shaft and drying wet steam separated by the steam separator, the steam separator and the steam dryer, A plate-shaped member provided between the control rod drive shaft guide tube and the plate-shaped member, the penetrating portion is configured in a seal structure, and as the steam separator, A boiling water reactor, wherein the steam separator according to any one of the above items 5 is installed. 7. A reactor core provided in a reactor pressure vessel,
A control rod drive shaft for inserting or removing a control rod from the upper part of the core with respect to the core, a steam-water separator for separating gas-liquid two-phase flow generated in the core into wet steam and separated water, A steam dryer for annularly installing a control rod drive shaft guide tube for guiding the rod drive shaft and drying the wet steam separated by the steam / water separator, and installed at an upper end of the steam dryer. The ring-shaped top plate is fixed to the side surface of the pressure vessel using a seal structure, and is fixed to an upper lid of the pressure vessel and includes a control rod drive mechanism housing for guiding the control rod drive shaft and the control rod drive shaft guide tube. The connecting portion is disposed in a region where the wet steam upstream of the steam dryer inlet exists, and the steam-water separator according to any one of claims 1 to 5 is installed as the steam-water separator. Features a boiling water reactor.