JPH0431077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a nuclear reactor containment vessel, and particularly to a reactor containment vessel suitable for use in a boiling water reactor.

[Background of the Invention] Boiling water reactors (ABWRs) with internal pumps are being developed. this
The ABWR reactor containment vessel has a dry well, a pressure suppression chamber filled with cooling water, a pedestal, and a space inside the pedestal. The reactor pressure vessel with an internal pump installed at the bottom is
It is installed at the top end of the pedestal. A pressure suppression chamber surrounds the pedestal. The dry well is isolated from the pressure suppression chamber and is provided above the pressure suppression chamber. The reactor pressure vessel is located within the drywell. The pedestal inner space is formed within the pedestal below the reactor pressure vessel, and faces the pressure suppression chamber with the pedestal interposed therebetween. The space inside the pedestal is a space where control rod drive device replacement work is performed. This space is communicated with the outside of the reactor containment vessel through a tunnel for the purpose of transporting exchange equipment, etc.
During normal operation, the tunnel is closed with a hatch, and opened during the above-mentioned replacement work. A vent pipe connected to the drywell opens into the cooling water of the pressure suppression chamber.

In the event of a loss of coolant accident, high-temperature, high-pressure cooling water in the reactor pressure vessel becomes steam and is released into the dry well and the inner space of the pedestal. This vapor is vented through a vent pipe into the cooling water in the suppression chamber and condenses. The dry well and the pedestal inner space are filled with gas. Therefore, in the event of a loss of coolant accident, before the steam is released into the cooling water in the suppression chamber, the gas existing in the dry well and the space inside the pedestal is released into the cooling water in the suppression chamber through the vent pipe. . Since the gas is non-condensable, it floats in the cooling water and reaches the gas phase in the pressure suppression chamber above the cooling water level.

[Object of the Invention] An object of the present invention is to provide a compact nuclear reactor containment vessel.

[Summary of the Invention] The present invention has a dry well in which a nuclear reactor vessel is disposed, a pedestal that supports the reactor vessel, a dry well disposed around the pedestal and filled with a coolant, Moreover, the pressure suppression chamber is separated from the dry well, the vent flow path guides the steam released into the dry well into the coolant of the pressure suppression chamber, and the inside of the pedestal is provided below the reactor vessel. The space formed in
In a reactor containment vessel having a tunnel connecting the space and the outside of the reactor containment vessel, a concrete member is installed in the space in an area that does not interfere with the operation and maintenance inspection of equipment in the space. The reactor containment vessel is characterized in that the cross-sectional area of the lower part of the reactor containment vessel is smaller than the cross-sectional area of the upper part of the reactor containment vessel, and the tunnel is passed through the pressure suppression chamber, and the concrete member is inserted into the space. By installing the space in an area that does not interfere with the operation and maintenance of the equipment, and making the cross-sectional area of the lower part of the space smaller than the cross-sectional area of the upper part, the volume of the space can be reduced, and the amount of gas in this space can be reduced. , so as to reduce the need for containing the gas in the pressure suppression chamber, and furthermore, by passing the tunnel through the pressure suppression chamber and into the bottom concrete, the entire structure is shifted upwardly and the upward movement is reduced. This eliminates the problem of increasing the size of the reactor, and the synergistic effect of these effects allows the reactor containment vessel to be made smaller.

In the present invention, in an ABWR, the internal pump is installed at the bottom of the reactor vessel, so the inside diameter of the pedestal is larger than that of the conventional type, and the reactor pressure is transferred to the space inside the pedestal below the pressure suppression chamber. A tunnel leading from outside the vessel is installed, and the space inside the pedestal and the reactor containment vessel become larger not only in the inner diameter direction but also in the vertical direction, and waste is created in the lower part of the space formed inside the pedestal below the reactor vessel. This was done by focusing on the fact that there is a space that is That is, the space inside the pedestal only needs to be a space necessary for the control rod drive device replacement work, that is, a space within a range that does not impede movement of the traveling carriage of the control rod drive device replacement device. As a result of these studies, it was found that there was wasted space near the inner wall of the pedestal at the bottom of the space formed inside the pedestal. The inventors came up with the idea that in order to eliminate this wasted space, it would be better to fill this space, and that in order to reduce the thickness of the concrete at the bottom, it would be better to pass a tunnel through the pressure suppression chamber. This led to his invention.

[Embodiment of the Invention] A preferred embodiment of the present invention applied to ABWR will be described based on FIGS. 1 and 2.

The reactor containment vessel 1 has a dry well 2, a pressure suppression chamber 3, a pedestal 8, a vent pipe 9, an equipment loading tunnel 11, a pedestal inner space 15, and a concrete member 14. Reactor containment vessel 1
is installed on a base concrete mat 13. A cylindrical pedestal 8 is installed on a base concrete mat 13. The pressure suppression chamber 3 surrounds the pedestal 8. That is, the pressure suppression chamber 3 has a donut shape.
The pressure suppression chamber 3 is filled with cooling water 4 .
Above the liquid level 6 of the cooling water 4 in the pressure suppression chamber 3,
It has become gas phase space 5. The ceiling of the pressure suppression chamber 3 is formed by a diaphragm floor 7.
The dry well 2 is located above the diaphragm floor 7. The reactor pressure vessel 17 is installed at the upper end of the pedestal 8. A cylindrical gamma ray shield 16 is installed at the upper end of the pedestal 8 and surrounds the reactor pressure vessel 17. The pedestal inner space 15 is formed inside the pedestal 8 below the reactor pressure vessel 17 . The pedestal inner space 15 is also a dry well. The dry well 2 includes a reactor pressure vessel 17 and a γ-ray shield 16
It communicates with the pedestal inner space 15 by an annular gap 29 between the pedestal and the pedestal. The pressure suppression chamber 3 is isolated from the dry well 2 and the pedestal inner space 15 by a diaphragm floor 7 and a pedestal 8. A plurality of vent pipes 9 are provided within the pedestal 8 and are arranged at equal intervals in the circumferential direction of the pedestal 8. Each vent pipe 9 has at its lower end a horizontal pipe section 10 that opens into the cooling water 4 . The upper part of each vent pipe 9 is connected to the dry well 2 and the pedestal inner space 15.

Ten internal pumps 18 are installed on the bottom plate of the reactor pressure vessel 17. These internal pumps 18 are arranged at equal intervals in the circumferential direction. A heat exchanger 19 is installed at the upper end of the pedestal inner space 15 at a position closer to the inner wall of the pedestal 8 than the internal pump 18 is. The heat exchanger 19 is connected to the internal pump 1
8 and is provided in pair with internal pump 1.
It cools the cooling water that performs the cooling of step 8. That is, the cooling water cooled by the heat exchanger 19 is supplied to the internal pump 18, and the high temperature cooling water discharged from the internal pump 18 is supplied to the heat exchanger 1.
Returned to 9.

A number of control rod drive housings 20 are attached to the lower head plate of the reactor pressure vessel 17. These control rod drive housings 20 are
It is arranged closer to the center axis of the reactor pressure vessel 17 than each internal pump 18 . A control rod drive device 21 is installed within each control rod drive device housing 20 . Control rod drive device 21
performs operations for moving control rods (not shown) present in the reactor pressure vessel 17 into and out of the reactor core.

A control rod drive device replacement device 22 that performs the replacement work of the control rod drive device 21 is installed in the pedestal inner space 15.
is installed inside. Control rod drive exchange device 2
2 is a rotating truck 23 that moves on an annular rail 27 as shown in Japanese Patent Application No. 139517/1982, a traveling truck 24 that moves on a straight rail (not shown) installed on the rotating truck 23, and a traveling truck 24 that moves on a straight rail (not shown) installed on the rotating truck 23. It consists of a mast 25 provided on a truck 24, an attachment/detachment device (not shown) that moves up and down along the mast 25, and a cart (not shown) that has the function of raising and lowering a control rod drive device. The attachment/detachment device attaches and detaches bolts that connect the control rod drive device 21 and the control rod drive device housing 20. The mast 25 is the traveling bogie 2
When the cart is mounted and the control rod drive device 21 is moved in and out of the control rod drive device housing 20, it is in a vertical state, and the cart is mounted on the mast 25. When it is removed from the main body and when it is attached to it, it is in an overturned state (horizontal state). The mast 25 is rotated between vertical and horizontal positions near the center axis of the reactor pressure vessel 17. Other structures of the control rod drive device exchange device 22 are disclosed in Japanese Patent Application Laid-Open Nos. 52-140793 and 1987-35223. The annular rail 27 is attached to the cylindrical concrete member 14. This concrete member 14
functions as a support member of the control rod drive device exchange device 22.

The concrete member 14 is installed on the base concrete mat 13 at the bottom of the pedestal inner area 15. The outside of the concrete member 14 is in contact with the inner surface of the pedestal 8. The inner diameter D ₁ of the concrete member 14 is smaller than the inner diameter D ₂ of the pedestal 8. Therefore, the pedestal inner space 15 is
It has a stepped space with a large inner diameter at the top and a small inner diameter at the bottom. That is, the cross-sectional area of the lower part of the pedestal inner space 15 is smaller than the cross-sectional area of its upper part. The inner diameter of the upper part of the pedestal 8 must be large because it is necessary to install an internal pump 18 and a heat exchanger 19, especially the latter. The inner diameter D ₁ of the concrete member 14 is set so as not to obstruct the movement of the traveling cart 24 or the mast 25 for replacing the control rod drive device 21 attached to the control rod drive device housing 20 disposed at the outermost periphery (point X). It can be made as small as possible. The area below the upper end of the concrete member 14 in the pedestal inner space 15 is a movement space for the traveling carriage 24 of the control rod drive device exchange device 22 .

In this embodiment, the inner diameter of the concrete member 14 is
D ₁ is a lifting device 2 for maintenance of the internal pump 18 at the bottom of the pedestal inner space 15.
8 is provided, so that it has a size up to the outer surface of the lifting device 28. However, the lifting device 28 is located directly below the internal pump 18.
One unit is installed for each internal pump 18, and as shown in FIG. 2, a gap is formed between the elevating devices 28 that are adjacent to each other in the circumferential direction. It is also possible to make the concrete member 14 protrude between these gaps and reduce the inner surface of the concrete member 14 to the position of the diameter of the moving area of the traveling carriage 24 described above.

In this embodiment, the position of the upper end of the concrete member 14 matches the level of the lower surface of the equipment loading tunnel 11. However, the height of the concrete member 14 can be increased to such an extent that there is no problem in taking out the heat exchanger 19 during maintenance.

When performing maintenance and inspection on the internal pump 18, the internal pump 18 is removed from the reactor pressure vessel 17 after raising the elevating platform (not shown) of the elevating device 28, and is placed vertically on the elevating platform. placed on top. Then, the lifting platform is lowered to near the level of the rotating carriage 23, and the internal pump 18 is turned over using a chain block or the like. The cart removed from the internal pump 18 and the mast 25 described above is taken out of the reactor containment vessel 1 via the equipment delivery tunnel 11 and transported to a predetermined location within the reactor building (not shown). be done. The reactor containment vessel 1 is installed inside a reactor building.

The equipment loading tunnel 11 penetrates inside the pressure suppression chamber 3 above the bottom surface of the pressure suppression chamber 3 . One end of the equipment loading tunnel 11 is connected to the pedestal inner space 15. The other end of the equipment loading tunnel 11 is connected to an external area of the reactor containment vessel 1 via a hatch 12 . Equipment loading tunnel 1
1 is installed above the bottom surface of the pressure suppression chamber 3, the height of the reactor containment vessel 1 is reduced.

Due to a loss of coolant accident, reactor pressure vessel 17
When steam is released, the gas in the dry well 2 and the pedestal inner space 15 flows into the vent pipe 9 through the upper opening 9A and the horizontal opening 9B, and flows into the cooling water 4 of the pressure suppression chamber 3 through the horizontal pipe part 10. and then reaches the gas phase space 5. In this embodiment, since the concrete member 14 is installed in the pedestal inner space 15, the space volume of the pedestal inner space 15 is approximately 100% larger than that without it.
It has become smaller by about ³ m. In other words, since the volume of the dry well portion (the total volume of the dry well 2 and the pedestal inner space 15) becomes smaller, the volume of gas flowing into the gas phase space 5 of the pressure suppression chamber 3 in the event of a loss of coolant accident is reduced. do. Therefore,
Since the volume of the gas phase space 5 can be reduced accordingly, the reactor containment vessel 1 can be made more compact.

The steam released in the coolant loss accident is discharged into the cooling water 4 from the horizontal pipe section 10 through the vent pipe 9 and is condensed.

When a coolant loss accident occurs, cooling water is sprayed from a number of spray nozzles (not shown) provided at the top of the dry well 2 to condense the steam released into the dry well 2 . This sprayed cooling water is the cooling water 4 inside the pressure suppression chamber 3.
was supplied by a pump. Most of the sprayed cooling water is returned to the pressure suppression chamber 3 through the vent pipe 8 while condensing the steam within the dry well 2 . However, some of the sprayed cooling water falls into the pedestal inner space 15 through the annular gap 29 and accumulates therein. The cooling water accumulated in the pedestal inner space 15 is not returned to the pressure suppression chamber 3 unless it rises to the level of the horizontal opening 9B. Therefore, by performing the above spraying, the amount of cooling water 4 in the pressure suppression chamber 3 is gradually reduced. In anticipation of such a decrease,
The pressure suppression chamber 3 is filled with a necessary amount of cooling water 4. In this embodiment, the pedestal inner space 1
Since the concrete member 14 is installed inside the pedestal 5, the volume of the pedestal inner space 15 is smaller than that without the concrete member 14, as described above. Therefore, the amount of cooling water that accumulates in the pedestal inner space 15 during spraying is reduced by about 100 m ³ . In other words, the amount of cooling water 4 filled in the pressure suppression chamber 3 can be reduced by about 100 m ³ .
The volume inside the pressure suppression chamber 3 can be reduced. This also allows the reactor containment vessel 1 to be made compact. The cooling water accumulated in the pedestal inner space 15 is returned to the pressure suppression chamber 3 through the vent pipe 9 from the horizontal opening 9B.

Making the reactor containment vessel 1 more compact as described above leads to a reduction in the volume of the reactor building.

The concrete member 14 is in contact with the inner surface of the pedestal 8 as described above. Therefore, the concrete member 14 is configured to reinforce the lower part of the pedestal 8. This significantly improves the earthquake resistance of the pedestal 8.

Furthermore, the concrete member 14 also serves as a support member for the control rod drive device exchange device 22, as described above. For this reason, the control rod drive device exchange device 2
2. There is no need to provide a separate support member for the annular rail 21.

The concept of installing the concrete member 14 in the pedestal inner space 15 of this embodiment can also be applied to the conventional mark-type reactor containment vessel. In this case, the same effect can be obtained, although the degree of effect is lower than that of the above-mentioned embodiment.

[Effects of the Invention] According to the present invention, by providing a concrete member, the volume of the space inside the pedestal below the reactor vessel can be reduced, and the space inside the pedestal can be accessed from outside the reactor containment vessel. Because the tunnel to the reactor is passed through the suppression chamber, based on both of these considerations, the reactor containment vessel can be made significantly more compact.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a nuclear reactor containment vessel which is a preferred embodiment of the present invention, and FIG. 2 is a cross-sectional view taken from FIG. 1...Reactor containment vessel, 2...Dry well,
3... Pressure suppression chamber, 4... Cooling water, 5... Gas phase space, 8... Pedestal, 9... Vent pipe, 11...
... Equipment delivery tunnel, 14 ... Concrete member, 15 ... Pedestal inner space, 17 ... Reactor pressure vessel, 18 ... Internal pump, 19
...Heat exchanger, 21...Control rod drive device, 22...
...Control rod drive exchange device.

Claims (1)

[Scope of Claims] 1. A dry well in which a nuclear reactor vessel is disposed, a pedestal that supports the reactor vessel, a dry well disposed around the pedestal and filled with a coolant; a pressure suppression chamber separated from the reactor vessel; a vent channel for guiding steam released into the dry well into the coolant of the pressure suppression chamber; and a vent flow path formed inside the pedestal below the reactor vessel. In a reactor containment vessel having a space and a tunnel connecting the space and the outside of the reactor containment vessel, a concrete member is installed within the space in an area that does not interfere with the operation and maintenance inspection of equipment within the space. A reactor containment vessel characterized in that the cross-sectional area of the lower part of the space is smaller than the cross-sectional area of the upper part of the space, and the tunnel is passed through the pressure suppression chamber. 2. The reactor containment vessel according to claim 1, wherein the concrete member is in contact with the inner surface of the pedestal no.