JP7058244B2 - Reactor containment vessel - Google Patents

Description

The present invention relates to a reactor containment vessel.

In a pressurized water reactor (PWR), the primary coolant (light water) is pressurized so that it does not boil, and this primary coolant is heated by the thermal energy generated by the fission reaction of the reactor. Then, the high-temperature and high-pressure primary coolant is sent to the steam generator to boil the secondary coolant (light water), and the generated high-temperature and high-pressure steam turns the turbine to generate electricity. There is.

Pressurized water reactors are provided with a safety structure to prevent the reactor from becoming heated in the event of a loss of primary coolant. The security structure is equipped with a recirculation pool room and recirculation pump equipment. The recirculation pool chamber is provided on the lower floor of the reactor containment chamber in which the reactor is stored, and communicates with the reactor containment chamber through an opening provided on the floor surface of the reactor containment chamber, and also has a floor surface. A sump is provided in the reactor to store the emergency coolant. The recirculation pump equipment is configured to suck up the emergency coolant from the sump and discharge it into the reactor containment chamber. As a result, the emergency coolant that has flowed from the reactor storage chamber through the opening into the recirculation pool chamber is circulated (reused).

Japanese Unexamined Patent Publication No. 2016-142687

In the reactor building at the time of an accident, various foreign substances (hereinafter referred to as debris) such as heat insulating materials, concrete pieces, and chemical components exuded from concrete are generated due to pipe breakage. These debris, together with the coolant sprayed for cooling the inside of the reactor building, flow into the recirculation pool room installed under the reactor building through the openings provided on the floor surface. A sample strainer is installed in the recirculation pool room to filter out the debris that has flowed in with the coolant. However, if the amount of debris flowing in is too large, the filtering is delayed and the sump strainer is blocked by the accumulated debris, which may lead to an increase in pressure loss due to the subsequent debris flowing in.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reactor containment vessel capable of reducing the amount of debris flowing into the recirculation pool chamber.

In order to solve the above problems, the present invention employs the following means.

(1) The reactor containment vessel according to one aspect of the present invention is provided on the lower floor of the reactor containment chamber in which the reactor is stored and the reactor containment chamber, and the reactor containment chamber is provided through an opening. It is provided with a recirculation pool chamber having a sump on the floor surface, and has a screen body which is installed over the entire circumference of the opening in the reactor containment chamber and extends inward. The screen body is composed of an inner tubular portion installed so as to form a communication hole communicating with the opening, and an outer tubular portion installed around the inner tubular portion. The tubular portion is made of a first glazing member, and is provided with a groove portion that penetrates the side wall of the outer tubular portion in the thickness direction and exposes the side wall of the inner tubular portion.

(2) In the reactor containment vessel according to (1), it is preferable that the end of the side wall of the inner tubular portion is in contact with the inner wall surface of the opening.

(3) In the reactor containment vessel according to any one of (1) or (2), the more the position of the plurality of grooves is farther from the recirculation pool chamber, the more the inner tubular portion is provided. It is preferable that the side wall is formed so as to have a large exposed area.

(4) In the reactor containment vessel according to any one of (1) to (3), a staircase structure portion is installed around the outer tubular portion, and the staircase structure portion is a stepped portion. It is preferable to have a communication hole that communicates with the groove portion.

(5) In the reactor containment vessel according to (4) above, a plate-shaped second grating member attached so that a part of the side surface is in contact with each step constituting the staircase structure is further attached. It is preferable to have.

In the reactor containment vessel of the present invention, a screen body is provided around the opening on the floor surface of the reactor containment chamber. The screen body is composed of an inner cylindrical portion made of a grating member and an outer tubular portion having a groove portion for exposing the inner tubular portion thereof. Therefore, of the coolant and debris that have reached the periphery of the screen body, the coolant is allowed to flow into the opening through the groove of the outer tubular portion and the mesh of the inner tubular portion, and only the debris is trapped. Therefore, it has a function of preventing the flow into the opening. Therefore, in the reactor containment vessel of the present invention, the amount of debris flowing into the recirculation pool chamber can be reduced.

It is a vertical sectional view of the reactor containment vessel which concerns on one Embodiment of this invention. (A) is an enlarged cross-sectional view of a screen body constituting the reactor containment vessel of FIG. 1. (B) It is a top view of the screen body of (a). It is a figure which shows the modification of the screen body of FIG. It is a figure which shows the modification of the screen body of FIG.

Hereinafter, the reactor containment vessel according to the embodiment to which the present invention is applied will be described in detail with reference to the drawings. In addition, in the drawings used in the following explanation, in order to make the features easy to understand, the featured parts may be enlarged for convenience, and the dimensional ratios of each component may not be the same as the actual ones. not. Further, the materials, dimensions, etc. exemplified in the following description are examples, and the present invention is not limited thereto, and the present invention can be appropriately modified without changing the gist thereof.

FIG. 1 is a vertical sectional view schematically showing the configuration of the reactor storage structure 100 according to the first embodiment of the present invention. As shown in FIG. 1, the reactor containment structure 100 mainly includes a reactor containment vessel 10, a recirculation pump facility 20, and a first screen body (samp screen body) 30.

The reactor containment vessel 10 includes a reactor containment chamber 40 in which the reactor 41 is stored, and a recirculation pool chamber 50 provided on the lower floor of the reactor containment chamber 40 and storing the coolant L. An opening 60 is formed at a boundary portion (partition wall) between the reactor storage chamber 40 and the recirculation pool chamber 50, and both are communicated with each other through the opening 60. In the reactor storage chamber 40, a second screen body (weir) 70 is installed around the opening 60. A sump 51 is provided on the floor (bottom surface) 50A of the recirculation pool room. In the present embodiment, the case where one sump 51 is provided is illustrated, but the number of sumps 51 may be two or more.

The reactor containment vessel 10 according to the present embodiment is a cylindrical vessel having a dome-shaped top, and contains a pressurizer 42 and a steam generator 43 in addition to the reactor 41. The primary coolant (light water) is pressurized by the pressurizer 42, and further heated by the heat energy generated by the fission reaction of the reactor 41. The high temperature and high pressure primary coolant is sent to the steam generator 43 to boil the secondary coolant (light water).

A turbine 44, a generator 45, and a condenser 46 are provided outside the reactor containment vessel 10. The turbine 44 is rotated by the secondary coolant (steam) boiled by the steam generator 43, and drives the generator 45. The steam that has rotated the turbine 44 is condensed by the condenser 46, becomes a secondary coolant, and is sent to the steam generator 43. In this way, the secondary coolant (light water) circulates between the steam generator 43, the turbine 44, and the condenser 46.

As shown in FIG. 1, the sump 51 is preferably provided at a position on the floor surface 50A of the recirculation pool chamber so as not to overlap with the opening 60 in a plan view from the reactor storage chamber 40 side. In this case, the coolant L that has flowed into the recirculation pool chamber 50 through the opening 60 will flow into the sump 51 across the recirculation pool chamber 50, so that the occurrence of local retention can be suppressed. Can be done.

The recirculation pump equipment 20 sucks the coolant L stored in the recirculation pool chamber 50 from the sump 51, guides it to the upper part of the reactor storage chamber 40, and discharges it into the reactor storage chamber 40 from there. It is configured. As specific recirculation pump equipment 20, for example, as shown in FIG. 1, a pipe 21 arranged from the sump 51 to the ceiling of the reactor storage chamber 40, a circulation pump 22 provided in the middle of the pipe 21, And those provided with a shower nozzle 23 provided on the ceiling of the reactor containment chamber 40.

The coolant L stored in the recirculation pool chamber 50 is pumped from the sump 51 by the circulation pump 22, passes through the pipe 21, and is discharged from the shower nozzle 23. Then, the coolant L discharged from the shower nozzle 23 cools the equipment stored in the reactor storage chamber 40, and then flows into the recirculation pool chamber 50 through the opening 60. In this way, the coolant L circulates between the sump 51, the pipe 21, the shower nozzle 23, the reactor storage chamber 40, and the recirculation pool chamber 50.

The sump screen body (first screen body) 30 is composed of a plurality of sump screens 32. Each of the plurality of sump screens 32 is formed in a box shape with the openings facing the sump 61 side, and a plurality of holes smaller than the size of debris are provided on the side surfaces (four surfaces) and the upper surface thereof, and cooling is performed from the holes. It is configured so that the liquid L can flow in. When the water level of the coolant L is lower than the height of the sump screen 32, the coolant L flows in only from the side surface of the sump screen 32. When the water level of the coolant L exceeds the height of the sump screen 32, the coolant L flows in from both the side surface and the upper surface of the sump screen 42.

FIG. 2A is an enlarged view of a part R including the second screen body 70 (hereinafter referred to as the screen body 70) in the vertical cross-sectional view of the reactor storage structure of FIG. The screen body 70 is installed in the reactor storage chamber 40 over the entire circumference of the opening 60 communicating with the recirculation pool chamber 50 (so as to surround the entire opening 60), and extends inside the reactor storage chamber 40. Has a shape to be used. FIG. 2B is a plan view of the screen body 70 from its extending direction E.

The screen body 70 has a tubular structure, and is mainly composed of an inner tubular portion 71 and an outer tubular portion 72. The inner tubular portion 71 constitutes the inside of the tubular structure, and the hollow portion 71a is installed so as to form a communication hole that communicates with the opening 60. From the viewpoint of increasing the fixing strength, it is preferable that the end portion 71b of the side wall of the inner tubular portion 71 is inserted through the opening 60 so as to be in contact with the inner wall surface thereof. The "cylindrical structure" here has a hollow portion extending in substantially one direction and has openings at both ends, and the shape of the cross section is not limited. For example, the cross section is circular. It may be a cylinder of the above, or it may be a rectangular cylinder having a rectangular cross section.

The inner tubular portion 71 may be installed so that the end portion 71b of the side wall is placed on the floor surface 40A of the reactor storage chamber, in which case the central axis 71c is the center 60c of the opening 60. It is preferable that it is installed so as to pass through it, and it is preferable that its inner diameter 71d substantially coincides with the diameter 60d of the opening.

The inner cylindrical portion 71 is made of a wire mesh, a perforated member (first grating member), or the like, and has a certain thickness. The thickness is preferably about 10 to 30 mm.

The outer cylindrical portion 72 is installed around the inner tubular portion 71 and constitutes the outside of the tubular structure. The outer cylindrical portion 72 has a constant thickness according to the load capacity.

Grooves (drainage holes) 72b are provided at predetermined intervals 72a in the extending direction E of the screen body to penetrate the side wall of the outer tubular portion 72 in the thickness direction and expose the side wall of the inner tubular portion 71. There is. Here, the case where the three groove portions 72b are provided in the extending direction E is illustrated, but the number of the groove portions 72b is not limited. The width of the groove portion 72b in the extending direction E increases as the distance from the floor surface 40A increases. That is, the plurality of groove portions 72b are formed so that the exposed area of the side wall of the inner tubular portion becomes larger as the provided position is farther from the recirculation pool chamber 50.

The shape of the cross section of the groove portion 72b seen from the depth direction (horizontal direction in FIG. 2) is not limited, and may be circular or rectangular. However, it is assumed that the size of the cross section increases as the distance from the floor surface 40A increases in the extending direction E. The "size of the cross section" referred to here shall be defined by either the cross-sectional area or the minimum dimension of the cross section.

FIG. 2B shows an example in which four groove portions 72b are provided, but the number of the groove portions 72b is not limited. From the viewpoint of efficiently flowing the coolant L, the larger the cross-sectional area of the groove portion 72b is, the better, and it is preferable that the groove portion 72b has a shape that spreads over almost the entire circumference excluding the portion supporting the upper stage. Further, from the viewpoint of making the flow of the coolant L uniform, it is preferable that the coolant L is arranged symmetrically (radially) with respect to the center 60c of the opening.

The groove portion 72b functions as a flow path for the coolant L. When the coolant L flows around the screen body 70 and the liquid level of the coolant L rises to reach the height of the groove 72b, the coolant L passes through the groove 72b and further constitutes the inner tubular portion 71. It passes through the hole of No. 1 and reaches the opening 60, and flows into the recirculation pool chamber 50.

The groove portion 72b may be blocked by the flow of large-sized debris together with the coolant L. In that case, the liquid level of the coolant L rises further and flows into the groove portion 72b in the upper stage.

In the initial stage where the liquid level L is low, small debris such as fiber debris arrives, so the cross section (cross-sectional area or minimum dimension) on the lower stage side that flows in at this stage may be small. On the other hand, the debris that arrives when the liquid level rises after a predetermined time has passed includes many large ones, so the groove on the upper stage that flows in at this stage is sufficient to prevent blockage due to debris. Must have a large size. Therefore, it is preferable that the plurality of groove portions 72b have a larger cross section as the position where they are provided is farther from the recirculation pool chamber 50. In other words, it is preferable that the larger the distance from the floor surface 40A, that is, the upper side, the larger the cross section (cross-sectional area or minimum dimension) of the groove portion 72b to be installed.

When the liquid level of the coolant L reaches the top of the screen body, the coolant L flows from the opening 60 into the recirculation pool chamber along the inner wall surface of the inner tubular portion 71. At this time, the debris contained in the coolant L is trapped or sheared and subdivided due to the influence of friction with the grating member constituting the inner tubular portion 71. Further, due to friction with the grating member, the flow of the coolant L is disturbed, bubbles can be caught in the coolant L, and debris contained in the coolant L can be attached to the bubbles and floated together with the bubbles. ..

FIG. 3 is a cross-sectional view of the screen body according to the modified example of the screen body 70 of FIG. A staircase structure portion 73 is installed around the outer tubular portion 72. The staircase structure portion 73 is formed so that the area becomes intermittently smaller as the distance from the opening 60 increases in a plan view from the extending direction E. The staircase structure portion 73 has a communication hole 73d that communicates with the groove portion 72b provided in the outer tubular portion 72 at the step portion thereof.

FIG. 4 is a cross-sectional view of the screen body 80 according to the modified example of the screen body 70 of FIG. The screen body 80 further has a plate-shaped second grating member 74 attached so that a part of the side surface is in contact with the side wall of the outer tubular portion 72. The second grating member 74 is attached to the plate-shaped support member 75 and is supported by the columnar member 76. Other configurations are the same as the configuration of the screen body 70, and the parts corresponding to the screen body 70 are indicated by the same reference numerals regardless of the difference in shape.

By attaching the second grating member 74 and the plate-shaped porous member 75, when the liquid level of the coolant L that has flowed to the screen body 80 rises, debris that tends to rise together with the coolant L is trapped. be able to. This makes it possible to enhance the effect of reducing the amount of debris reaching the opening 60.

As described above, in the reactor containment vessel 100 according to the present embodiment, the screen body 70 is provided around the opening 60 on the floor surface of the reactor containment chamber 40. The screen body 70 is composed of an inner tubular portion 71 made of a grating member and an outer tubular portion 72 having a groove portion 72b that exposes the inner tubular portion 71 to the periphery thereof. Therefore, the screen body 70 flows the coolant L out of the coolant L and the debris that have reached the periphery thereof into the opening 60 via the groove portion 72b of the outer tubular portion and the mesh of the inner tubular portion 71. It has a function of trapping only debris and preventing it from flowing into the opening 60. Therefore, in the reactor containment vessel 100 according to the present embodiment, the amount of debris flowing into the recirculation pool chamber 50 can be reduced.

100 ... Reactor containment structure 10 ... Reactor containment vessel 20 ... Recirculation pump equipment 21 ... Piping 22 ... Circulation pump 23 ... Shower nozzle 30 ... Samp screen body (No. 1) Two-screen body)
31 ... Pedestal 32 ... Samp screen 40 ... Reactor containment chamber 41 ... Reactor 42 ... Pressurizer 43 ... Steam generator 44 ... Turbine 45 ... Generator 46・ ・ ・ Condenser 50 ・ ・ ・ Recirculation pool room 50A ・ ・ ・ Floor surface 51 ・ ・ ・ Samp 60 ・ ・ ・ Opening 70 ・ ・ ・ Screen body (first screen body)
71 ... Inner tubular portion 72 ... Outer tubular portion 73 ... Staircase structure portion 73d ... Communication hole 74 ... Second grating member 75 ... Support member 76 ... Columnar member L・ ・ ・ Coolant

Claims (5)

The reactor storage room where the reactor is stored and the reactor storage room
It is provided on the lower floor of the reactor containment chamber, and is provided with a recirculation pool chamber which communicates with the reactor containment chamber through an opening and has a sump on the floor surface.
In the reactor containment chamber, it has a screen body that is installed all around the opening and extends inward.
The screen body is composed of an inner tubular portion installed so as to form a communication hole communicating with the opening, and an outer tubular portion installed around the inner tubular portion.
The inner cylindrical portion is made of a first grating member.
A reactor containment vessel characterized in that a groove portion is provided that penetrates the side wall of the outer tubular portion in the thickness direction and exposes the side wall of the inner tubular portion. The reactor containment vessel according to claim 1, wherein the end of the side wall of the inner tubular portion is in contact with the inner wall surface of the opening. The first aspect of the present invention is characterized in that the plurality of grooves are formed so that the exposed area of the side wall of the inner tubular portion becomes larger as the provided position is farther from the recirculation pool chamber. Or the reactor containment vessel according to any one of 2. One of claims 1 to 3, wherein a staircase structure portion is installed around the outer tubular portion, and the staircase structure portion has a communication hole communicating with the groove portion in the step portion. Reactor containment vessel as described in. The reactor containment vessel according to claim 4 , further comprising a plate-shaped second grating member attached so that a part of the side surface is in contact with each step constituting the staircase structure portion. ..

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