JPH0519085A - Protective device inside containment vessel - Google Patents

Abstract

(57) [Summary] [Purpose] The communication hole of the pedestal erected in the boiling water reactor containment vessel should not be blocked by falling objects in case of an accident so that the function of the reactor containment vessel is not impaired. To [Structure] Pedestal 2 installed upright in containment vessel 1
The support structure unit 10 is provided in the communication hole 6 of the above, and the protective structure 11 is installed on the support structure unit 10. Protective structure
The upper part of 11 projects into the upper dry well 8a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor containment for preventing the inside of a communication hole of a pedestal installed upright in the reactor containment vessel of a boiling water reactor from being blocked by a fallen object, for example, when a pipe breaks. Concerning the protective device inside the container.

[0002]

2. Description of the Related Art The reactor containment vessel of an improved boiling water reactor has a prismatic shape as shown in FIG. 3, and in this reactor containment vessel 1, a cylindrical pedestal 2 is provided at the center.
And the reactor pressure vessel 3 erected on this pedestal 2.
And a suppression chamber 4 is provided at the bottom.

A vent pipe 5 is provided in the suppression chamber 4, and the vent pipe 5 communicates with a communication hole 6 formed in the pedestal 2. The communication hole 6 has a fan-shaped cross section similar to a base having an upper side of about 2 m, a lower side of 1.5 m, and a height of about 1 m, and has a length of about 8 m to support the reactor pressure vessel 3. It is provided above and below the pedestal 2. Further, the inside of the reactor containment vessel 1 is divided into a dry well 8 and a wet well 9, and the dry well 8 is divided into an upper dry well 8 a and a lower dry well 8 b, and both are connected by a communication hole 6. In the wet well 9, a discharge pipe 7 that is immersed in the suppression chamber 4 is provided.

[0004]

The jet at the time of pipe breakage in the reactor containment vessel 1 does not directly act on the communication hole 6 which communicates with the vent pipe 5 of the improved boiling water reactor. However, there is still a possibility that the equipment inside the reactor containment vessel 1 damaged by this jet may block the communication hole 6.

Communication hole 6 of improved boiling water reactor containment vessel
The peripheral portion is extremely narrow due to the arrangement equipment in the reactor containment vessel, and it is very difficult to install a protective structure in the communication hole 6. Further, the pipes, cables, ducts, etc. connecting the upper dry well 8a to the lower dry well 8b are inserted through the communication hole 6,
These installations need to be supported at the entrance of the communication hole 6. Further, the upper dry well 8a and the lower dry well 8b have a role of temporarily absorbing the energy released when the built-in pipe is broken. Usually upper dry well 8
The a and the lower dry well 8b are connected by the communication hole 6, and the released energy is absorbed in both spaces.

However, when pipe breakage is assumed in the upper dry well 8a and the communication hole 6 is blocked due to this effect, the energy absorbing space is limited to the upper dry well 8a, which is disadvantageous in terms of energy absorption efficiency. There is.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a protective device in a reactor containment vessel capable of avoiding the blockage of the communication hole even in the case of an expected accident.

[0008]

According to the present invention, a support structure unit is provided in a communication hole of a pedestal erected in a boiling water reactor containment vessel, and the support structure unit is projected onto the upper dry well. It is characterized by installing a protective structure.

[0009]

[Operation] When the communication hole is closed due to the fall of the equipment inside the reactor containment vessel that is damaged by the pipe breakage jet in the reactor containment vessel, the vapor from the pipe breakage port is led to the suppression pool and condensed to reduce the pressure. It is difficult to secure the function of the reactor containment vessel, but this function is secured by providing a protective structure. Further, by integrating the protective structure with the support structure unit, it is possible to significantly reduce the work of installing the protective structure on site. When installing the protective structure, the structure of the protective structure can be simplified by arranging it so as to avoid the pipe breakage jet.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a protection device for a reactor containment vessel according to the present invention will be described with reference to FIGS. FIG. 1 shows only a main part of the present invention.
The internal structure is the same as that shown in FIG. Also,
FIG. 2 is an enlarged perspective view of the main part of FIG. That is, in the reactor containment vessel 1 having the upper dry well 8a and the lower dry well 8b, and having the communication hole 6 that communicates the both dry wells 8a and 8b, it is provided in the pedestal 2 as shown in FIG. A step-like support structure unit 10 is provided in the communication hole 6, and a protective structure 11 is installed on the support structure unit 10. The protective structure 11 is configured so that it can be used as a supporting device for piping cables, ducts, and the like. That is, the piping cable 13 and the like are attached to the protective structure 11 via the support 12, and the protective structure 11 is at an arrangement level that is not affected by the facility 14 inside the containment vessel and the pipe breaking jet 15. ing. As shown in FIG. 2, the support structure unit 10 has a steel plate 16 and a horizontal beam 17 between itself and the protective structure 11, and the tip of the protective structure 11 has a communication hole on the side of the upper dry well 8a. 6 is projected at the entrance site.

Therefore, according to the above-mentioned embodiment, it is possible to avoid the blockage of the communication hole 6 in the event of an expected accident. That is, since the entrance of the communication hole 6 is a narrow place, the protective structure 11 projecting the communication hole 6 is fixed by using a part of the structural material inside the reactor containment vessel already installed. Has been done. The protective structure 11 ensures the pressure reducing function of the reactor containment vessel 1, the structure can be extremely simplified, and the on-site installation work can be reduced. By forming the platform with the steel plate 16 on the upper surface of the protective structure 11, it becomes easy to access the installation installed above the communication hole 6. Also a protective structure
When installing 11, the protection structure 11 can be simplified by avoiding the pipe breaking jet 15.

[0012]

According to the present invention, by providing the protective structure, the function of reducing the pressure of the reactor containment vessel can be secured and the structure thereof can be simplified, and in addition, the on-site installation work can be reduced. You can

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a protective device in a reactor containment vessel according to the present invention.

FIG. 2 is a perspective view showing a main part in FIG.

FIG. 3 is a vertical cross-sectional view schematically showing the inside of a conventional reactor containment vessel.

[Explanation of symbols]

1 ... Reactor containment vessel, 2 ... Pedestal, 3 ... Reactor pressure vessel, 4 ... Suppression chamber, 5 ... Vent pipe, 6
... communication hole, 7 ... discharge pipe, 8 ... dry well, 9 ... wet well, 10 ... support structure unit, 11 ... protective structure, 12
… Support, 13… Plumbing cable, 14… PCV equipment,
15… Jet, 16… Steel plate, 17… Horizontal beam.

Claims (1)

Claim: What is claimed is: 1. A support structure unit is provided in a communication hole of a pedestal provided upright in a boiling water reactor containment vessel, and the support structure unit is protruded into the upper dry well for protection. A protective device in a containment vessel characterized by having a structure installed.