JPH02157690A - Natural heat radiation type storage container - Google Patents

Abstract

PURPOSE:To accelerate the up-down heat conduction in the outer peripheral pool of the storage container and to suppress the generation of a guise ring by fitting a porous material on the partition wall surface between the outer peripheral pool of a nuclear reactor storage container and a nuclear reactor container. CONSTITUTION:The porous material 12 is arranged on the surface of the partition wall between the outer peripheral pool 7 of the storage container and the nuclear reactor storage container 6 and many cavities 13 are present in the porous material 12, so boiling is easily caused as compared with a normal smooth surface. Namely, the porous material 12 increases in heat exchange area as compared with the smooth surface, so peripheral pool water is heated speedily. Then steam bubbles 14 are produced at the bottom parts of cavities 13 and grown gradually to start boiling in a short time. Further, steam bubbles produced by the boiling accelerates the stirring in the storage container outer peripheral pool 7. Consequently, the stirring in the outer peripheral pool 7 of the nuclear reactor container is accelerated to reduce the upper-lower temperature distribution, thereby suppressing the generation of the guise ring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a natural heat dissipation type containment vessel suitable for cooling a nuclear reactor containment vessel without loss of coolant.

(Prior Art) FIG. 7 shows a conventional natural heat dissipation type containment vessel as shown in, for example, Japanese Patent Application Laid-Open No. 63-75594. A dry well 3 in which a furnace pressure vessel 2 is stored, and a pressure suppression boule 4
It is equipped with a reactor containment vessel 6 consisting of a wet well 5 having a
A containment vessel outer perimeter boule 7 is provided. Pool water from an upper supplementary water pool 8 is supplied to this outer circumferential pool 7 of the containment vessel via a float valve 9, and the inside of the outer circumferential pool 7 of the containment vessel is supplied via an atmospheric vent pipe 10. It is open to the atmosphere.

In addition, in FIG. 7, the reference numeral 11 is the vent pipe that connects the dry well 3 and the wet well 5.

In the above configuration, in the event of a loss of coolant accident, steam released from the reactor pressure vessel 2 is transmitted to the pressure suppression pool 4 through the steam vent pipe 11, and then to the containment vessel outer peripheral pool 7. The reactor containment vessel 6 is cooled by the temperature increase and evaporation of the pool water in the containment vessel outer peripheral pool 7.

(Problem to be Solved by the Invention) Incidentally, in the conventional natural heat dissipation type containment vessel, the containment vessel outer peripheral pool 7 has a width W of 1 as shown in FIG.
m, and the height H is about 10 to 30 m, so natural convection tends to be insufficient, and the saturation temperature is higher in the lower part due to water head pressure, causing high temperature water to boil under reduced pressure as it rises and cause bumping. However, unstable flow called geyser is likely to occur. In other words, the area of the shaded area A in Figure 8 is proportional to the amount of heat removed, but this area becomes smaller as you go deeper into the pool water, and a stable cooling effect cannot be expected. There's a problem.

In addition, the water temperature in the outer peripheral pool 7 of the containment vessel is initially in a subcooled state 1, but the water temperature rises due to the heat transmitted from the wall surface of the reactor containment vessel 6, and eventually reaches the saturation temperature, as shown in Fig. 9. From the wall of the reactor containment vessel 6,
llL will start.

By the way, the height H of the wall surface of the reactor containment vessel 6 is 1
0 to 30 m, and since it is a vertical surface, bubbles generated on this wall rise along the wall, and as they move toward the top, the bubbles coalesce to cover the wall, and from the wall to the outer circumferential pool 7 of the containment vessel. There is a problem in that the heat dissipation into the air is extremely poor compared to the normal case, and a stable cooling effect cannot be obtained.

The present invention has been made in consideration of these points, and an object of the present invention is to provide a natural heat dissipation type containment vessel that can be stably cooled over a long period of time.

[Structure of the invention]

(Means for Solving the Problem) A first aspect of the present invention provides, as a means for achieving the above object, a containment vessel outer peripheral pool on the outside of the reactor containment vessel,
In a natural heat dissipation type containment vessel in which the reactor containment vessel is cooled by temperature rise and evaporation of the pool water, a porous material is attached to the partition wall between the containment vessel outer peripheral pool and the reactor containment vessel. Features.

Further, as a means for achieving the above object, a second invention of the present invention provides a pool outside the containment vessel outside the reactor containment vessel, and cools the reactor containment vessel by raising the temperature and evaporating the pool water. In the natural heat dissipation type containment vessel, a heat pipe is installed in the outer peripheral pool of the containment vessel to exchange heat between the surface layer and the deep layer of the pool water.

Furthermore, the third aspect of the present invention provides, as a means for achieving the above-mentioned object 1, a containment vessel outer peripheral pool is provided outside the reactor containment vessel, and the reactor containment vessel is cooled by heating and evaporating the pool water. In a natural heat dissipation type containment vessel that performs
The partition wall surface of the outer peripheral pool of the storage vessel and the reactor containment vessel is characterized in that it is a slope that slopes toward the upper end toward the reactor containment vessel.

(Function) In the natural heat dissipation type containment vessel according to the first aspect of the present invention, a porous material is attached to the partition wall surface of the containment vessel outer peripheral pool from the reactor containment vessel. This porous material has many fine pits on its surface, so it boils and becomes more fragile than a smooth surface. Stirring is promoted,
The temperature distribution between the upper and lower sides is reduced, and the occurrence of geysering is suppressed.

In addition, in the natural heat dissipation type containment vessel according to the second aspect of the present invention, heat transfer between the surface layer and the deep layer of the pool water is promoted by the heat pipe arranged in the outer peripheral boule of the containment vessel, The temperature distribution between the upper and lower sides is reduced, and the occurrence of geysering is suppressed.

Furthermore, in the natural heat dissipation type containment vessel according to the third aspect of the present invention, the partition surface of the containment vessel outer circumferential boule from the reactor containment vessel is a slope that slopes toward the upper end toward the reactor containment vessel side. There is. For this reason, the bubbles generated on this wall surface do not rise along the wall surface, but at a certain distance from the wall surface, making it difficult for the bubbles to coalesce, and the area near the wall surface is covered with steam bubbles. Things will disappear. As a result, heat transfer characteristics are improved compared to the conventional method, and stable cooling becomes possible.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows an example of a natural heat dissipation type containment vessel according to the present invention, which includes a dry well 3 in which a reactor pressure vessel 2 containing a reactor core 1 is housed, and a pressure suppression vessel. It is equipped with a reactor containment vessel 6 composed of a wet well 5 having a boule 4, and both wells 3.5 and 3.5.
are connected by a steam vent pipe 11.

In addition, a containment vessel outer peripheral pool 7 is provided outside the reactor containment vessel 6, as shown in FIG. The atmosphere is supplied via a valve 9, and an atmospheric vent pipe 1 is provided inside the containment vessel outer circumferential boule 7.
0 to the atmosphere.

On the partition surface of the containment vessel outer peripheral pool 7 from the reactor containment vessel rA6, that is, on the outer peripheral part of the wall surface of the reactor containment vessel 6,
A porous material 12 is installed as shown in FIGS. 1 and 2. This porous substance 12 is made of, for example, a metal fiber called felt, a metal mesh, or a single sintered metal, and its material is copper, stainless steel, bronze, or nickel. These are attached to the outer wall surface of the reactor containment vessel 6 by a general sintering method.

As shown in FIGS. 2 and 3, this porous material 12 has many fine depressions (hereinafter referred to as cavities) 13.
The steam bubbles 14 existing in each of these cavities 13 gradually grow and boiling takes place. This has the characteristic that boiling is accelerated compared to the case of a smooth surface.

Next, the operation of this embodiment will be explained.

In the event of a loss of coolant accident, steam released from the reactor pressure vessel 2 passes through the steam vent pipe 11 to the pressure suppression boule 4.
and then to the outer boule 7 of the containment vessel. The inside of the reactor containment vessel 6 is cooled by the temperature rise and evaporation of the pool water.

In this way, cooling after a loss of coolant accident can be achieved over a long period of time without requiring power, operation, or human intervention.

By the way, as shown in FIG. 1, a porous material 12 is arranged on the partition wall surface of the containment vessel peripheral pool 7 from the reactor containment vessel 6, and this porous material 12 has a large number of cavities 13. Because of its existence, it is in a boiling and crystalline state compared to a normal smooth surface.

That is, since the porous material 12 has a larger heat exchange area than a smooth surface, the surrounding pool water is quickly heated. Then, as shown in FIG. 2, steam bubbles 14 are generated at the bottom of the cavity 13, and these steam bubbles 14 gradually grow as shown in FIG. 3, and boiling begins in a short time. Furthermore, the bubbles generated by the boiling promote agitation within the containment vessel outer circumferential boule 7, reducing the vertical temperature distribution and suppressing the occurrence of geysering. Therefore, a large amount of heat can be removed from the reactor containment vessel 6, making it possible to downsize the reactor containment vessel 6 and reduce the cost of the reactor building.

FIG. 4 shows a second embodiment of the present invention.
In place of the porous material 12 in the embodiment, a heat pipe 22 is installed in the outer boule 7 of the containment vessel to exchange heat between the surface layer and the deep layer of the pool water. Note that the other points have the same configuration as the first embodiment.

By installing the heat pipe 22 in this manner, heat transfer in the upper and lower directions within the containment vessel outer peripheral boule 7 is promoted, the upper and lower temperature distribution is reduced, and the occurrence of geysering is suppressed. Therefore, the same effects as in the first embodiment can be expected.

FIG. 5 and FIG. 6 show a third embodiment of the present invention, in which the porous material 12 in the first embodiment or the heat pipe 22 in the second embodiment is replaced with a containment vessel outer peripheral pool. 7, the partition wall surface with the reactor containment vessel 6,
The slope is gradually inclined toward the reactor containment vessel 6 toward the upper end. Note that other points have the same configuration as those of the above-described embodiments.

In this way, since the outer circumferential surface of the reactor containment vessel 6 is sloped, the bubbles generated on the wall will not rise along the wall, as shown in FIG. It will rise after that. Therefore, it becomes difficult for the bubbles to coalesce at the top, and the vicinity of the wall surface is not covered with vapor bubbles.

Therefore, the heat transfer characteristics are improved compared to the conventional case,
It becomes possible to cool each other stably over a long period of time.

Note that the present invention is not limited to the embodiments described above, and, for example, the embodiments described above may be used in any combination.

〔Effect of the invention〕

As explained above, in the first aspect of the present invention, a porous material is installed on the partition wall between the containment vessel outer circumferential pool and the reactor containment vessel. Heat transfer is promoted and the occurrence of geysering can be suppressed.

In addition, the second aspect of the present invention is that a heat pipe is installed in the outer circumferential pool of the containment vessel to exchange heat between the surface layer and the deep layer of the pool water. Heat transfer between the upper and lower sides of the tube is promoted, and the occurrence of geysering can be suppressed.

Furthermore, in the third aspect of the present invention, the partition surface of the containment vessel peripheral pool from the reactor containment vessel is formed into a slope that gradually slopes toward the reactor containment vessel side toward the upper end. is not covered with vapor bubbles, improving heat transfer properties.

As a result, the amount of heat removed from the reactor containment vessel is increased (this makes it possible to stably cool the reactor containment vessel over a long period of time, as well as to reduce the size of the reactor containment vessel and, by extension, the size of the reactor building. can be expected to lead to significant cost reductions.

FIG. 5 is a diagram corresponding to FIG. 1 showing the second embodiment of the present invention, FIG. 5 is a diagram equivalent to FIG. 1 showing the third embodiment of the present invention, and FIG. Figure 7 is a sectional view showing a conventional natural heat dissipation type containment vessel, Figure 8 is an explanatory diagram showing the temperature distribution and amount of heat transfer in the outer circumferential pool of the containment vessel, and Figure 9 is a void on the wall surface of the outer circumferential pool of the containment vessel. FIG.

6... Reactor containment vessel, 7... Containment vessel outer peripheral pool, 12... Porous material, 13... Cavity, 22
···heat pipe.

Applicant's representative: Mr. Sato

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a natural heat dissipation type containment vessel showing the first embodiment of the present invention, Fig. 2 is an enlarged sectional view showing the structure of a porous material, and Fig. 3 is an explanation showing the mechanism of nucleate boiling in a cavity. Fig. 4 shows the present invention Fig. 2 Fig. 1 Fig. 3 J! P19 figure

Claims (1)

[Scope of Claims] 1. In a natural heat dissipation type containment vessel in which a containment vessel outer periphery pool is provided outside the reactor containment vessel and the reactor containment vessel is cooled by heating and evaporating the pool water, the containment vessel outer periphery A natural heat dissipation type containment vessel characterized by having a porous material attached to the partition wall between the pool and the reactor containment vessel. 2. In a natural heat dissipation type containment vessel in which a containment vessel outer circumferential pool is provided outside the reactor containment vessel and the reactor containment vessel is cooled by raising the temperature of the pool water and evaporating, the containment vessel outer circumferential pool has a A natural heat dissipation type containment vessel characterized by installing a heat pipe that exchanges heat between the surface layer and the deep layer of water. 3. In a natural heat dissipation type containment vessel in which a containment vessel outer circumferential pool is provided outside the reactor containment vessel and the reactor containment vessel is cooled by heating and evaporating the pool water, the reactor containment vessel in the containment vessel outer circumferential pool is A natural heat dissipation type containment vessel characterized in that the partition wall surface between the container and the reactor is a slope that slopes toward the upper end toward the reactor containment vessel.