JPS6360352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear reactor containment vessel, and more particularly to a structure around an opening in a reactor containment vessel having a reinforced concrete structure.

In general, a reactor containment vessel (hereinafter referred to as a containment vessel) with a reinforced concrete structure has a relatively greater degree of freedom in shape than a containment vessel with a steel plate structure, making it easier to plan the layout, and is advantageous in terms of construction time and construction costs. Moreover, there is no risk of low-temperature embrittlement of the receptacle, and it has excellent explosion resistance and is resistant to drop impact.

Figure 1 shows a reinforced concrete structure containment vessel for a boiling water reactor, and 1 is the containment vessel. This containment vessel 1 has a reinforced concrete body 2
It is a sealed pressure-resistant vessel formed by lining a liner plate 3a, and a reactor pressure vessel 4 is placed on a pedestal approximately in the center of the interior.
A suppression chamber 5 is provided in the lower part, and the upper dry well 6 and the suppression chamber 5 are connected by a plurality of vent pipes 7. Furthermore, an opening 8 is provided at the upper center of the vessel body 2 of the containment vessel 1 for inspecting the inside of the reactor pressure vessel 4 and for replacing fuel rods. This opening 8 is formed in a circular shape, and its inner peripheral surface is lined with a liner plate 3b similar to the vessel body 2, and a head 9 that closes the opening 8 from the outside is mounted on the top surface with a bolt or the like. It is attached removably.

By the way, in such a containment vessel 1, if an accident occurs in a nuclear reactor or the like and a steam/water mixture of water and steam is released into the dry well 6, the steam/water mixture will be vented as is well known. The water is ejected through the pipe 7 into the pool water of the suppression chamber 5, suppressing the increase in internal pressure. At this time, the internal pressure and temperature of the dry well 6 and the suppression chamber 5 change as shown in FIGS. 3 and 4, respectively. occurs. That is, the area around the opening 8 is directly hit by the shock wave from the reactor and receives a large pressure load P, and at the same time, a thermal gradient as shown in FIG. 5 is generated due to the difference in heat conduction between the liner plate 3b and the vessel body 2. . As a result, on the inner peripheral surface of the opening 8, the cylindrical liner plate 3b tries to extend vertically and circumferentially, causing the sixth
A tensile force f as shown in the figure is generated, and a compressive force g is generated in the liner plate 3b itself since its deformation is restrained by the container body 2.

In this way, undesirable stress is generated around the opening 8 of the containment vessel 1, but in the past, this stress had to be dealt with by increasing the strength of the container body 2, which was extremely unsatisfactory.

The present invention solves the above-mentioned conventional dissatisfaction by providing a heat insulating member on the center side of the opening of the liner plate at the opening.The heat insulating member prevents heat generated in the containment vessel during an accident from being conducted to the liner plate. Since it can be significantly alleviated, the compressive force and tensile force generated in the liner plate and vessel body can be reduced, respectively, and the integrity of the pressure boundary function of the containment vessel or the structural function of the vessel body can be greatly improved. The purpose is to provide a containment vessel.

The present invention will be explained in detail below based on the drawings.

7 to 9 show an embodiment of the present invention, and 2 in the figures is a container made of reinforced concrete having predetermined pressure resistance, earthquake resistance, etc. This vessel 2
A liner plate 3a for maintaining airtightness is tightly connected to the container body 2 by a liner anchor A and lined with the inner circumferential surface of the container, and an opening 8 is provided in the upper center of the container as in the conventional case. A liner plate 3b similar to the above is also attached to the inner circumferential surface of.

The upper end of the liner plate 3b of the opening 8 is formed higher than the upper surface of the container body 2, and the head 9 is detachably attached to the upper end, and at the same time, the container body 2 is attached to the outside (left side in FIG. 7). A structural member 10 is fixedly installed to transmit the tensile force f generated near the surface of the container body 2 to the inside of the container body 2, and inside the structural member 10 (on the right side in FIG. A heat insulating member 11 is provided to moderate conduction. This heat insulating member 11 is located between the liner plate 3a of the vessel body 2 and a collar-shaped locking member 12 provided inside the liner plate 3b of the opening 8 at approximately the same height as the top surface of the vessel body 2. Further inside, there is a heat insulating member 1.
Protective member 13 that prevents the air/water mixture from directly hitting 1.
is provided with an air gap 14 formed between it and the heat insulating member 11.

Like the heat insulating member 11, this protective member 13 is disposed between the locking member 12 and the liner plate 3a of the vessel body 2, and its radial movement is controlled by restraining members provided on the locking member 12 and the liner plate 3a, respectively. 15, the protection member 13 and the locking member 12 are restrained and blocked from the inside.
An appropriate gap G is maintained between them to allow vertical deformation of the protection member 13. Further, the spaces between the protective member 13, the locking member 12, and the liner plate 3a are sealed with sealing materials 16, and a stiffener 17 is provided on the inner peripheral surface of the protective member 13 to prevent buckling of the protective member 13. ing.

In addition, in the above, the thickness of the protective member 13 is
For example, when the pressure load P is 40t/m ² and the radius is 5.1m, the thickness is about 0.68cm, and if the thickness is 0.9cm
In this case, the amount of deformation in the radial direction is about 1.16 cm at most, and therefore, the sealing material 16 only needs to be a member that can withstand this degree of deformation. In addition, in order to relieve the stress on the mounting legs of the head 9, a sand cushion 18 may be provided at the upper corner of the body 2, as shown in FIG.

The present invention is constructed as described above, and if an accident should occur in the containment vessel 1, the high temperature and high pressure air/water mixture will directly hit the protection member 13. At this time,
Since the protection member 13 is formed in a cylindrical shape, it resists the force in the radial direction by acting as a "hoop" and deforms freely in the vertical direction. On the other hand, the heat is conducted to the heat insulating member 11 via the protection member 13, the sealing material 16, and the air gap 14, and is largely relieved by the heat insulating member 11 before being transmitted to the liner plate 3b of the opening 8. and structural member 10
It will be transmitted to the inside of the vessel body 2 through this process.

As described above, according to the present invention, the conduction of heat generated in the containment vessel to the liner plate in the event of an accident can be alleviated by the heat insulating member, so it is possible to significantly reduce the amount of heat generated in the containment vessel during an accident without increasing the strength of the vessel body. It is possible to provide a containment vessel that can easily improve the pressure boundary function of the containment vessel and the soundness of the structural function of the vessel.

Further, according to the present invention, since the protective member itself is supported so as to be thermally deformable, the effect of thermal deformation of the protective member is particularly limited to the liner plate that directly or indirectly supports the protective member. Nothing happens. Therefore, as the protective member, any material can be used as long as it is made of a material that is effective in protecting the heat insulating member even if it undergoes some thermal deformation.

[Brief explanation of the drawing]

Figures 1 to 6 explain conventional containment vessels, and Figure 1 is a vertical cross-sectional view of the entire containment vessel;
Figure 2 is a vertical sectional view showing the main part of the opening, Figure 3 is a pressure change diagram at the time of the accident, Figure 4 is a temperature change diagram, Figure 5 is a temperature distribution diagram near the liner plate, and Figure 6 is a diagram of the temperature distribution near the liner plate.
Figure A is a vertical cross-sectional view of the main part showing the state of stress action, and Figure 6B is a cross-sectional view of the opening. Also,
7 to 9 show one embodiment of the present invention, FIG. 7 is a longitudinal sectional view of the opening, and FIG. 8 is a longitudinal sectional view of the opening.
FIG. 9 is an enlarged vertical sectional view of the main part of the figure, and is a vertical sectional view showing a method of stress relaxation in the head mounting portion. 1... Reactor containment vessel, 2... Vessel, 3a, 3
b... liner plate, 8... opening, 11...
...Insulating member, 13...Protection member, 16...Sealing material, 18...Sand cushion.

Claims (1)

[Claims] 1. An opening is provided in the vessel body made of reinforced concrete, and a liner plate is lined at this opening and the inner peripheral surface of the vessel body, and a head that closes the opening from the outside is attached to and detached from the opening. In the reactor containment vessel that is freely attached, a heat insulating member is provided inside the liner plate stretched on the inner circumferential surface of the opening to reduce conduction of heat generated in the reactor containment vessel to the liner plate. A protective member is provided inside the heat insulating member to protect the heat insulating member, and these heat insulating members and protection members are provided on the liner plate of the vessel body and the liner plate of the opening. A nuclear reactor containment vessel, characterized in that it is supported by a locking member, and the protection member itself is supported so as to be thermally deformable.