JPS587958B2 - reactor containment system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reactor containment system for a boiling water reactor, and particularly to a reactor containment system for a boiling water reactor, and in particular, a reactor containment system in which a buffer member for a vent header in a pressure suppression chamber can be easily and quickly installed. Relating to a storage device.

A reactor containment system for a boiling water nuclear power plant is configured as shown in FIG. 1, for example.

That is, the pressure vessel 2 housing the reactor core 1 is mounted on the pedestal 3.
A containment vessel 4 is provided to enclose the pressure vessel 2, and this containment vessel 4 prevents leakage of high-pressure steam containing radioactive materials in the event of pipe rupture.

A truss-shaped pressure suppression chamber 5 is provided to surround the lower part of the containment vessel 4, and this pressure suppression chamber 5
Pool water 6 is stored therein, and a space 7 is provided above the pool water 6.

The pressure suppression chamber 5 and the containment vessel 4 are connected by a plurality of vent pipes 8, 8.

One end of each vent pipe 8 opens into the containment vessel 4, and the other end passes through the pressure suppression chamber 5 and is connected to a hollow annular vent header 9 disposed in the space 7.

A large number of pairs of downcomers 10, 10, which are steam discharge pipes, are connected downward to the vent header 9, and the lower end of each downcomer 10 is immersed in the pool water 6.

Note that, as shown in FIG. 2, the vent header 9 is fixed to the bottom of the pressure suppression chamber 5 by a plurality of supporting legs 12, 12.

For example, when the primary system piping of the pressure vessel 2 is ruptured, high-temperature, high-pressure water vapor enters the containment vessel 4 and the pressure inside the containment vessel 4 increases. It is discharged into the pool water of the pressure suppression chamber 5 through the .

In this way, steam from the pressure vessel 2 is discharged into the pool water 6 and condensed, thereby suppressing a rise in pressure within the containment vessel.

In the condensation process of the discharged steam, the water staying in the downcomer 10 is first pushed out into high-pressure steam by the action of the communicating pipe and collides with the bottom of the pressure suppression chamber 5 in the form of a jet, causing a large downward load to increase the pressure. Join the suppression chamber (see Figure 2).

Next, as the pool water rises due to the growth of bubbles formed at the bottom of the downcomer, an impact load is applied to the vent tube 9 and the vent pipe 8, and then an upward load is applied due to the compression of the upper part of the pool. These shock loads may compromise the integrity of the pressure suppression chamber.

Conventionally, in order to reduce the impact particularly applied to the vent header 9 and the vent pipe 8, a buffering method has been proposed in which a buffer rod is fixed parallel to the vent header 9, at a predetermined distance therefrom, and along the vent header. ing.

However, installing such a buffer rod in a pressure suppression chamber by welding requires many hours of labor, and is particularly difficult in the case of an existing reactor containment system.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a nuclear reactor containment system in which the buffer rod can be easily attached to the vent header in a short period of time.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 6.

In FIGS. 3 and 4, reference numeral 13 indicates a buffer rod;
This buffer rod 13 is a solid or hollow rod-like member with a circular cross section, for example, and includes a split member 14 and a support member 1, which will be described later.
5 into the pressure suppression chamber 5. It is fixed to the structure of the vent header 9 and is placed parallel to the vent header 9 with a predetermined gap therebetween.

In the embodiment shown in FIGS. 3 and 4, the vent header 9
It is arranged below and parallel to this.

As shown in FIG. 5, the split member 14 has a first part that can hold the outside of the vent header 9 without any gaps, for example.
and second attachment rings 16, 17, each of which has an integrally formed lug 18 at both ends with a through hole (not shown) for a bolt that fastens the two.

The buffer rod 13 is integrally connected to the second attachment ring 17 by, for example, welding, via a thick plate-like support 15.

Note that a plurality of second attachment rings 17 are attached along the length direction of the buffer rod 13.

Apply the buffer rod 13 to which a plurality of second attachment rings are attached as described above to the vent header from below, and
A first mounting ring 1 that is paired with the mounting ring.
By applying the buffer rod 6 from above the vent header 9 and fastening the mutually connecting ear pieces 18, 18 with bolts, the buffer rod 13 can be firmly and easily installed parallel to the vent header 9.

In the reactor containment system according to the embodiment of the present invention configured as described above, when steam is discharged from the vent pipe 8, the pool water level rises as the bubbles formed below the downcomer 10 grow. However, when the water surface comes close to the vent header 90, the water surface is bent by the buffer rod 13, so that the impact on the vent header 9 is greatly alleviated.

Note that since the diameter of the buffer rod 13 is much smaller than that of the vent head 9, the load applied to the buffer rod 13 is small.

FIG. 6 shows a modified embodiment of the present invention, in which a pair of split members 14 are attached to downcomers 10, 10 connected to the vent header 9, and a gap between these split members 14, 14 is shown. The base plate 1 forming part of the support 15
9 is bridged, and a buffer rod 13 is fixed onto this base plate 19 via U bolts 20 and spacers 21.

Since the operation and effect of the device shown in FIG. 6 are the same as those shown in FIGS. 3 and 4, detailed explanation thereof will be omitted.

As is clear from the above description, the present invention provides a shock absorbing rod for mitigating the impact on the vent header, which is attached to a structure in the pressure suppression chamber so as to support it, and which can be easily attached and detached. Since the buffer rod is fixed to the pressure suppression chamber via the member and the support coupled to the member, there is no need for welding work that requires a lot of time to attach the buffer rod.

Therefore, the installation cost of the buffer rod is reduced and the installation time is also shortened.

In addition, there is no need to change the dimensions or shape of the structure in the pressure suppression chamber to which the split member is attached, and the split member can be designed to match the shape, making it easy to install buffer rods in the existing pressure suppression chamber. is easy.

Furthermore, since the installation of the buffer rod inside the pressure suppression chamber requires only the fastening of the split members, installation and repair work can be carried out while pool water is being stored.

Furthermore, since the work of installing the buffer rods can be completed in a short time, the radiation exposure of the workers is also reduced.

It has various effects such as

In the illustrated embodiment, the pressure suppression indoor structure to which the split member is attached is a vent header or a downcomer, but it goes without saying that the support leg for fixing the vent header may also be used.

[Brief explanation of drawings]

FIG. 1 is a diagrammatic sectional view showing an example of the structure of a conventional reactor containment system, FIG. 2 is an enlarged cross-sectional view of a pressure suppression chamber thereof, and FIG. 3 is a reactor containment system according to an embodiment of the present invention. Diagrammatic partially enlarged sectional view of the pressure suppression chamber of the device, FIG. 4 is similar to FIG. 3 IV-I
FIG. 5 is an enlarged cross-sectional view of a buffer rod mounting portion, and FIG. 6 is a diagrammatic enlarged cross-sectional view of a pressure suppression chamber showing a modified embodiment of the present invention. 1...Reactor core, 2...Pressure vessel,
4...Containment vessel, 5...Pressure suppression chamber,
6... Pool water, 8... Vent pipe, 9
...Bent header, 10 ... Downcomer, 13 ... Buffer rod, 14 ... Split member, 15 ... Support body, 16. ...First attachment ring, 17...Second attachment ring, 18...Ear piece.

Claims (1)

[Scope of Claims] 1. A pressure vessel housing the reactor core, a containment vessel housing the pressure vessel, and a containment vessel disposed below the containment vessel,
A truss-shaped pressure suppression chamber that stores pool water inside,
a hollow annular vent header arranged concentrically within the pressure suppression chamber and fixed by a support leg; a plurality of vent pipes passing through the pressure suppression chamber and interconnecting the containment vessel and the vent header; A split member attached to a structure in the pressure suppression chamber so as to hold the structure in the pressure suppression chamber, in a device having a plurality of downcomers connected to a vent header and guiding steam in the vent header into pool water; A nuclear reactor containment system characterized in that a buffer rod is provided in parallel with a vent header via a support coupled to the vent header. 2. The reactor containment system according to claim 1, wherein the pressure suppression chamber structure to which the splitting member is attached is a vent header. 3. The reactor containment system according to claim 1, wherein the pressure suppression chamber structure to which the split member is attached is a downcomer. 4. The reactor containment system according to claim 1, wherein the pressure suppression chamber structure to which the split member is attached is a support leg of a vent header.