JP3160356B2 - Boiling water reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to a boiling water reactor in which a control rod is inserted vertically downward from the upper part of the core.

[0002]

2. Description of the Related Art A conventional boiling water reactor is configured as shown in FIG. A shroud 3 for accommodating a reactor core 2 is installed in the reactor pressure vessel 1, and a large number of fuel assemblies are provided between a core support plate 4 and an upper grid plate 5 provided at a lower portion and an upper portion of the shroud 3, respectively. Body 6 is installed.

[0003] A shroud head 7 is provided above the shroud 3, and a steam separator 9 is installed above the shroud head 7 via a stand pipe 8. Above the steam separator 9, a steam dryer 10 is provided. Below the core support plate 4, a control rod guide tube 11 for accommodating control rods inserted into the core 2 and a control rod drive mechanism 12 for driving the control rods are provided.

A plurality of jet pumps 13 are provided beside the core 2.
A recirculation pump that recirculates the cooling water in the reactor pressure vessel 1 is provided at the inlet side of the jet pump 13.
The discharge side pipe 16 of the recirculation system pipe 15 provided with 14 is open. On the side of the jet pump 13 of the reactor pressure vessel 1, the suction side pipe 17 of the recirculation system pipe 15 is open.

[0005] A main steam pipe 18 for guiding steam generated in the reactor core 2 to a turbine (not shown) is opened in a side wall surface of the steam dryer 10 of the reactor pressure vessel 1. Also, the reactor pressure vessel 1
A water supply pipe 19 for supplying cooling water to the reactor pressure vessel 1 is opened on the side of the stand pipe 8.

The fuel assembly 6 is surrounded by a fuel channel 20 as shown in FIG. 20 to maintain the rigidity of the fuel assembly, and the fuel assembly 6 is supported at a lower portion by a fuel support fitting 21 on a core support plate 4. The lower tie plate 22 which is the lower end structure of the fuel assembly 6 is inserted into the four holes 44.

As a result, the upper lattice plate 5
Positioning is performed by the channel fasteners 23 attached to the fuel channels of the four fuel assemblies in each lattice to secure a passage for the control rod. FIG. 4 shows the arrangement of the fuel assemblies 6 from above the upper lattice plate 5 and the relationship between the channel fasteners 23.
See Figure 21.

[0008]

By the way, by simplifying the lower structure of the reactor pressure vessel, control is performed vertically downward from the upper part of the core with the aim of further improving safety, improving workability at the time of periodic inspection, and reducing radiation exposure. When considering a reactor with a rod insertion system, there are the following problems.

In other words, in order to secure the control rod moving area in the upper part of the reactor core, the steam-water separator and the control rod guide tube interfere with each other, and it is difficult to perform appropriate arrangement setting in the conventional example. In addition, the control rod and the channel fastener interfere with each other at the upper part of the fuel assembly, so that it is impossible with the conventional fuel assembly support structure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and corresponds to a system in which control rods are inserted vertically downward from the upper part of the core to secure a moving area of the control rods in the upper part of the core and to further remove water and water. It is an object of the present invention to provide a boiling water reactor having a reactor internal structure in which a separator has an internal function that can perform its original function, and a reactor internal structure in which a control rod can be inserted from above the fuel assembly.

[0011]

According to a first aspect of the present invention, there is provided a reactor pressure vessel, a core disposed below the reactor pressure vessel, and a plurality of fuel assemblies constituting the reactor core. A plurality of control rods that are inserted downward and perform a withdrawal operation from below to upward, a shroud surrounding the plurality of fuel assemblies and forming a core, and an upper end opening of the shroud is closed and the plurality of A shroud head through which a control rod is vertically movably inserted; a plurality of steam-water separators which are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the core; A steam dryer provided above the steam-water separator and drying steam separated by the plurality of steam-water separators;
A control rod driving mechanism for driving the control rod, and a gap between a plurality of cylinders constituting the steam separator and the stand pipe are installed, and the control rod is housed therein, and
Penetrate the shroud head and reach the upper end of the fuel assembly
A control rod guide tube having a cross-shaped cross section integrally disposed until the control rod guide is installed above the steam separator.
A separator upper fixing plate for fixing the upper end of the pipe, and this separator
Control rod drive connected to the control rod on the upper fixed plate of the parator
Labyrinth was formed while the mechanism drive shaft was inserted
And a control rod drive mechanism shaft sealing portion .

According to a second aspect of the present invention, a reactor pressure vessel, a core disposed below the reactor pressure vessel, and a plurality of fuel assemblies constituting the core are inserted from above to below. A plurality of control rods for performing a pull-out operation from below and upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods moving up and down. A shroud head that is freely inserted, a plurality of steam-water separators that are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the reactor core, and a plurality of steam-water separators. constituting a steam dryer for drying the steam and separated in the plurality of gas-water separator provided above, the control rod drive mechanism that drives the control rod, the steam-water separator and standpipe The shroud at the gap in the number of cylinders
A control rod guide tube having a cross-shaped cross section which is installed on an upper part of the head and houses the control rod therein, and the shroud head
To be connected to the lower end surface of the control rod guide tube.
Connect the control rod guide extension pipe to the lower end face of the control rod guide extension pipe.
The length of the fuel assembly that is
Connection tube and joint surface between the connection tube and the control rod guide extension tube
And a tapered surface that slides on the joining surface.
Characterized in that that.

According to a third aspect of the present invention, a reactor pressure vessel, a core disposed below the reactor pressure vessel, and a plurality of fuel assemblies constituting the reactor core are inserted from above to below. A plurality of control rods for performing a pull-out operation from below and upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods moving up and down. A shroud head that is freely inserted, a plurality of steam-water separators that are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the reactor core, and a plurality of steam-water separators. A steam dryer that is provided above and dries the steam separated by the plurality of steam separators; and a control rod drive mechanism that drives the control rod, and is installed below the shroud head. At a grid point of the upper grid plate, a set of four fuel channels in contact with the grid points is set, and four fuel channels are collected around four vertices of each grid, and the center of the grid is a passage of the control rod. And a connecting member for fixing the upper portion of the fuel assembly and the upper lattice plate is provided.

According to a fourth aspect of the present invention, a reactor pressure vessel, a core disposed below the reactor pressure vessel, and a plurality of fuel assemblies constituting the core are inserted from above to below. A plurality of control rods for performing a pull-out operation from below and upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods moving up and down. A shroud head that is freely inserted, a plurality of steam-water separators that are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the reactor core, and a plurality of steam-water separators. A steam dryer that is provided above and dries the steam separated by the plurality of steam separators, and a control rod drive mechanism that drives the control rod, and is installed above the shroud head. A cross-shaped control rod guide tube for accommodating control rods therein is installed in the gap between the cylinders constituting the steam separator and the stand pipe, and the control rod guide tube penetrates the shroud head to form a fuel assembly. The fuel assembly upper structural member is provided integrally with the fuel assembly up to the upper end, and is provided with a mechanism for connecting the upper portions of adjacent fuel assemblies in order to secure a movement area of the control rod.

[0015]

According to the first aspect of the present invention, a cross-shaped control rod guide tube is disposed in the gap between the steam-water separator installed above the shroud head and the cylindrical body constituting the stand pipe, and penetrates the shroud head to reach the upper end of the fuel assembly. The horizontal movement of the control rod can be restrained by integrally installing the control rod, and the horizontal relative position between the control rod and the fuel assembly can be kept constant.

According to the second aspect of the present invention, by providing a cross-shaped connecting pipe for connecting the upper part of the fuel assembly and the control rod guide pipe welded to the shroud head, the upper part of the fuel assembly can be positioned in the horizontal direction so that the control rod can be positioned. Can be secured.

In the third aspect of the invention, the conventional channel fastener is abolished to eliminate a factor that hinders the insertion of the control rod from the upper part, and a set of four fuel channels surrounding the intersection of the upper grid plate is fixed. To secure the control rod movement path.

According to the fourth aspect of the present invention, a mechanism for connecting the fuel assembly adjacent to the upper structural member of the fuel assembly is provided, and a control rod moving path for inserting the control rod vertically downward from the upper part of the core is secured.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first invention will be described with reference to FIGS. In each of the drawings, the same portions as those shown in FIGS. 19 to 21 are denoted by the same reference numerals, and description of overlapping portions will be omitted, and only main portions will be described. 1 and 2 show only a main part of the present embodiment, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. 4 is a sectional view taken along the line BB of FIG.

That is, in FIGS. 1 to 4, a plurality of cylindrical bodies which stand at a certain interval in the horizontal direction and constitute a steam-water separator 9 and a stand pipe 8 installed above the shroud head 7. The control rod in the gap
A cross-shaped control rod guide tube 25 accommodating 24 therein is disposed. The control rod guide tube 25 penetrates through the shroud head 7 and is integrally provided up to the upper end of the fuel assembly 6.

The upper end of the control rod guide tube 25 is fixed to a separator upper fixing plate 26, and the steam flow in the control rod guide tube 25 that has not passed through the steam separator 9 is applied to the separator upper fixing plate.
In order to prevent the CRD drive shaft 27 connected to the control rod 24 from rising upward from 26, the CRD drive shaft 27 is inserted through the CRD shaft sealing portion 28 and led out to the upper portion.

According to the above configuration, the control rod guide tube 25 is horizontally supported by the shroud head 7 and the separator upper fixing plate 26, and can have a sufficiently rigid structure.
The horizontal relative position between the control rod 24 and the fuel assembly 6 is kept constant, and the performance of inserting the control rod 24 into the core 2 can be ensured.

FIG. 3 shows a cross section of the reactor core 2 as viewed from the direction of arrows AA when viewed from above. Fuel assembly 6 into which control rod 24 is inserted
Cross-shaped control rod guide tube 25 so as to cover the gap
Are arranged up to the upper end of the fuel assembly 6. FIG. 4 shows a cross section of the middle portion of the steam separator 9 as viewed in the direction of arrows BB. A control rod guide tube 25 is disposed in a gap between the cylindrical bodies constituting the steam separator 9 and accommodates the control rod 24 therein.

Although not shown, the steam dryer 10 installed above the steam-water separator 9 is provided with an annular drier, and a space for installing a control rod drive mechanism (CRD) is provided in the annular drier. Have.

FIG. 5 shows a detailed vertical cross section of the CRD shaft sealing portion 28. A labyrinth 29 is formed in the CRD shaft sealing portion 28 to increase the flow resistance of a steam flow that is going to rise through a gap between the CRD drive shaft 27 and rise without passing through the steam separator 9. Consideration is given to minimizing the flow rate of leaked steam.

The labyrinth 29 may be either a thread labyrinth that is easy to process or a ring labyrinth that has a large flow resistance. In the upper part of the labyrinth 29, pool water 30 for water sealing is accumulated by the moisture in the steam, and the leak steam can be sealed by the water head.

According to the first embodiment of the present invention,
In response to the system in which control rods are inserted vertically downward from the upper part of the core, the steam-water separator, stand pipe, and control rod guide tube can be arranged at the same level in the vertical direction. The size is reduced and the effect of shortening the reactor pressure vessel is obtained, which is advantageous for the earthquake resistance of the reactor building.

Next, an embodiment of the second invention will be described with reference to FIGS. In each drawing, the same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals, and the description of the overlapping parts will be omitted.

FIG. 6 is a perspective view of an embodiment of the second invention, and FIG. 7 is a front view showing FIG. 6 in a partial cross section.
This embodiment is a boiling water reactor having the following structure. Steam-water separator 9 installed above shroud head 7
In the stand pipe 8, a cross-shaped control rod guide pipe 25 containing a control rod 24 therein is arranged in a gap between a plurality of cylindrical bodies that constitute these and stand at regular intervals in the horizontal direction. I have. The lower end of the control rod guide tube 25 is inserted into and fixed to the shroud head 7, and the lower end of the control rod guide tube 25 is fixed.
The surface is joined to the upper end surface of the control rod guide extension tube 32 shown in FIG.
Connect. The upper end face of the control rod guide extension tube 32 is
It is fixed by welding in contact with the lower surface of the pad. Control rod guide
The lower end surface of the extension tube 32 is tapered from the inside to the outside.
The pa surface is formed. At the lower end of the control rod guide extension tube 32
Is a connection having a length up to the upper end of the fuel assembly 6.
A tube 31 is provided. Control rod plan on the upper end face of connecting pipe 31
The tapered surface that slides on the lower end surface of the inner extension tube 32 and the tapered surface that slides
Are formed. The upper end of the control rod guide tube 25 is fixed to the separator upper fixing plate 26, and the steam flow in the control rod guide tube 25 that has not passed through the steam separator 9 rises upward from the separator upper fixing plate 26. In order to prevent this, the CRD drive shaft 27 connected to the control rod 24 passes through the CRD shaft seal 28 and is led upward.

FIG. 8 is a cross-sectional view of the reactor core 2 as viewed from above, as viewed from the direction of arrows CC. The shroud head 7 and the fuel assembly 6 are shown in FIG.
FIG. 9 is a side view showing a partial cross section between the upper portions. At the time of the periodic inspection, the shroud head 7 is removed at the same time as the control rod guide tube 25, the stand pipe 8, the steam separator 9, etc., which are the upper structures thereof, and reassembled after the inspection.

The fuel assembly 6 is provided below the shroud head 7.
Even if the control rod guide extension tube 32 provided with a tapered portion at the lower portion which directly contacts the fuel rod, it is difficult to smoothly insert the control rod guide extension tube 32 into the upper portion of the fuel assembly 6 due to the positioning accuracy of the shroud head 7.

According to this embodiment, a slight and larger diameter than the control rod guide tube 25 provided on the shroud head 7 to <br/> under surface of the shroud head 7, a tapered lower end surface, short welding the <br/> control rod guide extension tube 32, connecting the connecting tube 31 of cross-shaped having a tapered upper end surface to the extension tube 32. to this
Positioning of the fuel channel 20 surrounding the more fuel assemblies 6 that Do possible <br/>.

As an assembly procedure, after the fuel assembly 6 is inserted, the connecting pipe 31 is inserted, and the fuel assembly 6 above the fuel assembly 6 is inserted.
And secures a moving path for the control rod 24. Finally also the shroud head 7 as the position of the shroud head 7 covering the top is deviated slightly in the fuel assemblies 6 and accuracy, the tapered end faces of the connecting pipe 31 and the taper of the lower end surface of the control rod guide extension tube 32 Slides, and the movement path of the control rod 24 is secured.

According to the second invention, it is possible to insert a control rod extending downward from the upper part of the reactor core, thereby further improving the basic safety of the reactor through simplification of the lower structure of the reactor pressure vessel. In addition, workability can be improved and radiation exposure can be reduced at the time of periodic inspection.

Next, an embodiment of the third invention will be described with reference to FIGS. In each drawing, the same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals, and the description of the overlapping parts will be omitted.

FIG. 10 is a perspective view of an embodiment of the third invention, and FIG. 11 is a front view showing a partial cross section. This embodiment is a system relating to a nuclear reactor having the following structure.
In the steam separator 9 and the stand pipe 8 installed above the shroud head 7, the control rod 24 is housed in a gap between a plurality of cylinders that constitute these and stand up at a certain interval in the horizontal direction. Cross-shaped control rod guide tube 25 is disposed.

The control rod guide tube 25 is provided for the shroud head 7
, And is integrally provided up to the upper end of the fuel assembly 6. The upper end of the control rod guide tube 25 is fixed to the separator upper fixing plate 26, and the steam flow in the control rod guide tube 25 that has not passed through the steam separator 9 is applied to the separator upper fixing plate.
A CRD drive shaft 27 connected to the control rod 24 is led upward through a CRD shaft seal 28 to prevent it from rising upward from 26.

FIG. 14 is a cross-sectional view of the reactor core 2 as viewed from above along arrow DD. At the time of the periodic inspection, the shroud head 7 is removed at the same time as the control rod guide tube 25, the stand pipe 8, the steam separator 9, etc., which are the upper structures thereof, and reassembled after the inspection.

In this embodiment, four fuel channels 20 are fixed as a set at a grid point on the upper grid plate 5 with a fixture 33, and a space for moving the control rod 24 is provided at the center of the grid. Make it possible. A perspective view and a front view of the fuel channel 20 and the fixture 33 are shown in FIGS. 12 and 13, respectively. Fixture 33
Consists of a mounting plate 34, a leg 36 fixed by a head 35 penetrating the mounting plate 34, and a tightening bolt 38 for mounting to the fuel channel 20. A leaf spring 37 protruding inward is attached to the leg 36.

Here, the three downwardly extending legs 36 are fitted into the fuel channel 20 from above, and are sandwiched by leaf springs 37 attached to the respective legs 36, thereby fixing the fuel channel 20. In consideration of prevention of a rolling accident and easiness of operation, it is used in a form installed in one fuel channel 20 in advance.

As an assembly procedure, after the three fuel assemblies 6 are inserted, the fuel channel 20 to which the fixture 33 is mounted is inserted, and the other three fuel assemblies 6 are fixed and the control rod 24 is moved. Secure a passage. Finally, the shroud head 7 is put on the upper part. Since the fuel assembly 6 is drawn to the upper lattice plate 5 side by the fixture 33, a space is provided in the center portion, and a movement passage of the control rod 24 is secured. FIG. 14 shows the upper lattice body 5,
The arrangement and installation of the fuel assemblies 6, control rods 24 and fixtures 33 are shown.

According to this embodiment, it is possible to insert a control rod vertically downward from the upper part of the reactor core, and to further improve the basic safety of the reactor and reduce the It is possible to improve workability and reduce exposure during inspection.

Next, an embodiment of the fourth invention will be described with reference to FIGS. Each figure is shown in FIGS.
The same parts as those described above are denoted by the same reference numerals and the description of the overlapping parts will be omitted.

FIG. 15 is a perspective view of this embodiment, and FIG. 16 is a front view showing a partial cross section. That is, in the steam separator 9 and the stand pipe 8 installed above the shroud head 7, the control rod 24 is housed in a gap between a plurality of cylindrical bodies that constitute these and stand at regular intervals in the horizontal direction. A cross-shaped control rod guide tube 25 is disposed.

The control rod guide tube 25 is provided for the shroud head 7
, And is integrally provided up to the upper end of the fuel assembly 6. The upper end of the control rod guide tube 25 is fixed to a separator upper fixing plate 26.

The CRD connected to the control rod 24 prevents the steam flow in the control rod guide tube 25 that has not passed through the steam separator 9 from rising upward from the separator upper fixing plate 26.
The drive shaft 27 passes through the CRD shaft sealing portion 28 and is led out to the upper portion. At the time of the periodic inspection, the shroud head 7 is removed at the same time as the control rod guide tube 25, the stand pipe 8, the steam separator 9, etc., which are the upper structures thereof, and reassembled after the inspection.

FIG. 17A is a cross-sectional view of the reactor core 2 viewed from above, as viewed from the direction of arrows EE, and FIG.
FIG. 17B shows a vertical cross section in the direction of arrow F, and FIG. 18 shows a partially enlarged perspective view of the embodiment.

In this embodiment, the upper structural member of the fuel assembly 6
A fuel assembly connecting mechanism 39 comprising a connecting convex portion 41 and a connecting concave portion 42 is provided at 40, and the adjacent fuel assemblies 6 are connected on the upper lattice plate 5 to secure a moving passage of the control rod 24.
An upper structural member 40 is fixed to the upper end surface of the fuel assembly 6 by four fixing bolts 43. As shown in the cross section of the connecting portion, both the connecting convex portion 41 and the connecting concave portion 42 are formed with a taper, so that the fuel assembly on either side can be accurately positioned when inserting and removing the fuel assembly. .

According to this embodiment, it is possible to insert a control rod vertically downward from the upper part of the reactor core, and to further improve the basic safety of the reactor by simplifying the lower structure of the reactor pressure vessel. It is possible to improve workability and reduce exposure during periodic inspection.

The above embodiment is similarly applied to a fuel assembly used in a boiling water reactor, which facilitates securing a space for moving control rods, and particularly improves control rod operability during an earthquake. effective.

[0051]

According to the present invention, in a boiling water reactor in which a control rod is inserted vertically downward from the upper part of the core, a passage for moving the control rod can be secured. In addition, the entire internal structure of the reactor can be reduced in the vertical direction, which contributes to shortening of the reactor pressure vessel.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a partial cross section of the internal structure of a boiling water reactor according to a first embodiment of the present invention from the upper part of a reactor core to a steam separator.

FIG. 2 is a front view showing a partial cross section in FIG.

FIG. 3 is a cross-sectional view cut along the direction of arrows AA in FIG. 2;

FIG. 4 is a cross-sectional view of FIG. 2 cut along the direction of arrows BB.

FIG. 5 is an enlarged longitudinal sectional view showing a CRD shaft sealing portion in FIG. 1;

FIG. 6 is a perspective view showing a partial cross section of the internal structure of the boiling water reactor according to the second embodiment of the present invention from the upper part of the reactor core to the steam separator.

FIG. 7 is a front view showing a partial cross section in FIG. 6;

FIG. 8 is a cross-sectional view of FIG. 7 cut along the direction of arrows CC.

FIG. 9 is a side view showing a part of the space between the shroud head and the fuel channel in FIG. 7;

FIG. 10 is a perspective view, partially in section, showing the internal structure of the boiling water reactor according to the third embodiment of the present invention from the upper part of the reactor core to the steam separator.

FIG. 11 is a front view showing a partial cross section in FIG. 11;

FIG. 12 is a perspective view showing a fuel channel and a fixture thereof in FIG. 11;

FIG. 13 is a front view of FIG.

FIG. 14 is a transverse cross-sectional view of FIG. 11 cut along the direction of the arrow DD.

FIG. 15 is a perspective view, partially in section, showing the internal structure of the boiling water reactor according to the fourth embodiment of the present invention from the upper part of the reactor core to the steam separator.

FIG. 16 is a front view showing a partial cross section in FIG. 15;

17A is a cross-sectional view of FIG. 16 cut in the direction of the arrow EE, and FIG. 17B is a longitudinal cross-sectional view cut and enlarged in the direction of the arrow FF in FIG.

FIG. 18 is a perspective view showing a relationship between an upper lattice plate and a fuel assembly connection mechanism in FIG. 15;

FIG. 19 is a longitudinal sectional view schematically showing the internal structure of a conventional boiling water reactor.

20 is a perspective view showing a partially assembled state of a loaded fuel assembly in FIG. 19;

FIG. 21 is an enlarged top view showing a part of the core in FIG. 19;

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Core, 3 ... Shroud, 4 ...
Core support plate, 5 ... Upper lattice plate, 6: Fuel assembly, 7 ... Shroud head, 8 ... Stand pipe, 9 ... Steam separator, 10 ... Steam dryer, 11 ... Control rod guide tube, 12 ... Control rod Drive mechanism, 13… Jet pump, 14… Recirculation pump, 15…
Recirculation system piping, 16… Discharge side piping, 17… Suction side piping, 18…
Main steam pipe, 19 ... water supply pipe, 20 ... fuel channel, 21 ... fuel support bracket, 22 ... lower tie plate, 23 ... channel fastener, 24 ... control rod, 25 ... control rod guide pipe, 26 ... separator upper fixed plate, 27 ... CRD drive shaft, 28 ... CRD shaft sealing part, 29 ... labyrinth, 30 ... pool water for water seal, 31 ... connecting pipe, 32 ... control rod guide extension pipe, 33 ... fixture, 34 ... mounting plate, 35 ... Head, 36: leg, 37: leaf spring, 38: tightening bolt, 39: coupling mechanism, 40: upper structural member, 41: coupling convex, 42: coupling concave, 43: fixing bolt.

Continuing from the front page (72) Inventor Nobuhiko Tanaka 1 Toshiba-cho, Komukai-shi, Kawasaki-shi, Kanagawa Prefecture Toshiba Research Institute, Inc. Toshiba Research Institute (72) Inventor Ritsuko Tsuzuki 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Corporation Yokohama Office (72) Inventor Yasuhiko Aida 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa TOSHIBA CORPORATION (56) References JP-A-57-122390 (JP, A) JP-A-58-7588 (JP, A) JP-A-4-366794 (JP, A) (58) Fields studied (Int. . ^7, DB name) G21C 7/14

Claims (4)

(57) [Claims] 1. A reactor pressure vessel, a lower core disposed in the reactor pressure vessel, and a plurality of fuel assemblies constituting the reactor core, which are inserted from above to below and from below. A plurality of control rods for performing a pulling-out operation upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods being vertically movably inserted. A shroud head, a plurality of steam separators which are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the core, and provided above the plurality of steam separators. A steam dryer for drying the steam separated by the plurality of steam separators, a control rod driving mechanism for driving the control rod, and a plurality of cylinders constituting the steam separator and the standpipe Is installed in the gap, through the shroud head along with housing the control rod inside
The fuel assembly is arranged integrally up to the upper end.
Control rod guide tube with a cross-section
Separator installed in the section to fix the upper end of the control rod guide tube
And the separator upper fixing plate.
Control rod drive mechanism connected to control rod
The control rod drive mechanism with the labyrinth formed
A boiling water reactor comprising: 2. A reactor pressure vessel, a lower core disposed in the reactor pressure vessel, and a plurality of fuel assemblies constituting the reactor core, which are inserted from above to below and from below. A plurality of control rods for performing a pulling-out operation upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods being vertically movably inserted. A shroud head, a plurality of steam separators which are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the core, and provided above the plurality of steam separators. A steam dryer for drying the steam separated by the plurality of steam separators, a control rod driving mechanism for driving the control rod, and a plurality of cylinders constituting the steam separator and the standpipe At the gap of the shroud head
A control rod guide tube having a cross-shaped cross section , which is installed at the top and stores the control rod therein, and which is attached to the shroud head.
Vignetting control rod guide to be joined to the lower end surface of the control rod guide tubes
And extension pipe, and joined to the lower end surface of the control rod guide extension tube of this set
A connecting pipe having a length reaching an upper end of the placed fuel assembly;
Formed on the joint surface between this connecting pipe and the control rod guide extension pipe
And a tapered surface that slides on the joint surface . 3. A reactor pressure vessel, a lower core disposed in the reactor pressure vessel, and a plurality of fuel assemblies constituting the reactor core, inserted from above to below and from below. A plurality of control rods for performing a pulling-out operation upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods being vertically movably inserted. A shroud head, a plurality of steam separators which are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the core, and provided above the plurality of steam separators. A steam dryer for drying the steam separated by the plurality of steam separators, and a control rod drive mechanism for driving the control rod, and an upper grid plate installed below the shroud head. At a grid point, a set of four fuel channels in contact with the grid point is formed as a set, and four fuel channels are collected around four vertices of each grid, and the center of the grid does not obstruct the passage of the control rod. A boiling water reactor characterized in that such a region is secured and a connecting member for fixing the upper part of the fuel assembly and the upper lattice plate is provided. 4. A reactor pressure vessel, a lower core disposed in the reactor pressure vessel, and a plurality of fuel assemblies constituting the reactor core, which are inserted from above to below and inserted from below. A plurality of control rods for performing a pulling-out operation upward, a shroud surrounding the plurality of fuel assemblies to form a core, an upper end opening of the shroud being closed, and the plurality of control rods being vertically movably inserted. A shroud head, a plurality of steam separators which are erected at the upper end of the shroud head via a standpipe to separate steam and steam generated from the core, and provided above the plurality of steam separators. A steam dryer for drying the steam separated by the plurality of steam-water separators, and a control rod drive mechanism for driving the control rod, and a steam-water separator installed on an upper portion of the shroud head. And, in the gap between the cylindrical bodies constituting the stand pipe, a cross-shaped control rod guide tube for accommodating the control rod therein is installed, and the control rod guide tube penetrates the shroud head and reaches the upper end of the fuel assembly. A boiling water reactor, wherein a mechanism for integrally connecting and connecting upper portions of adjacent fuel assemblies to secure a movement area of the control rod is provided in a fuel assembly upper structural member.