JPS642231B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a reactor containment vessel of a nuclear power plant, and in particular, the present invention relates to a reactor containment vessel of a nuclear power plant. Regarding the reactor containment vessel located.

(Prior Art) A conventional nuclear reactor containment vessel will be described below with reference to FIG.

The reactor containment vessel 1 includes a reactor pressure vessel 2, a dry well 3 that houses piping and equipment connected to the reactor pressure vessel 2, and a supplement that is separated from the dry well 3 and stores pool water 4. It is made up of a construction pool 5. The dry well 3 and the suppression pool 5 are separated and isolated by a pedestal 6 on which the reactor pressure vessel 2 is placed and a diaphragm floor 7. Further, a communication hole 8 is formed near the diaphragm floor 7 of the pedestal 6, and a bottom 9 of the dry well 3 is formed.
is located below the water level A in the suppression pool 5.

Now, if any of the piping, equipment, etc. connected to the reactor pressure vessel 2 in the dry well 3 breaks, the following phenomenon will occur. first,
Reactor coolant flows into the dry well 3 from the fracture point and turns into steam, increasing the pressure in the dry well 3. Subsequently, the air and steam in the dry well 3 pass through the vent pipe 10 to the suppression pool 5.
The dry well 3 is cooled by the pool water 4, which lowers the pressure in the dry well 3. Therefore, the greater the number of vent pipes 10, the lower the pressure rise in the dry well can be suppressed.

At the same time, the emergency core cooling system pump 11 is activated to send water in the suppression pool 5 to the reactor pressure vessel 2 to cool the reactor core (not shown) in the pressure vessel 2. The water that cooled the core flows out into the dry well 3 from the fracture location. At the same time, the containment vessel spray system pump 12 is activated to spray water 4 from the suppression pool 5 into the dry well 3 via the containment vessel spray header 13.
In this way, water begins to accumulate from the bottom 9 of the dry well 3, and after this water accumulates up to the upper end of the vent pipe 10, the water 4 returns to the suppression pool 5 from the communication hole 8 through the vent pipe 10. .

That is, in the event that piping, equipment, etc. connected to the reactor pressure vessel 2 break in the dry well 3, the water 4 in the suppression pool 5 will reach the upper end of the vent pipe 10, that is, the position of the communication hole 8. It will accumulate in the dry well. This accumulated water is
It cannot be used to cool the subsequent reactor pressure vessel 2 and dry well 3 because it does not have a discharge path. Therefore, it is necessary to prepare an extra amount of water for the suppression pool 5 to initially accumulate at the bottom 9 of the dry well 3, and therefore, it is necessary to design the suppression pool 5 to have a large capacity. .

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and its first purpose is to prevent damage to the dry well in the event that piping or equipment breaks in the dry well. To obtain a reactor containment vessel capable of reducing the volume of a suppression pool by reducing the amount of water accumulated in a well 3. A second object is to provide a reactor containment vessel that can reduce pressure rise in the dry well in the unlikely event that piping, equipment, etc. break in the dry well.

[Structure of the Invention] (Means for Solving the Problems) That is, in the reactor containment vessel of the present invention, the lower part of the dry well is located below the water level of water stored in the suppression pool, and the dry well In a reactor containment vessel in which a large number of vent pipes are arranged to communicate between a well and the suppression pool,
The lower end opening is immersed in the suppression pool water, and the upper end opening is at a position lower than the upper end opening position of the vent pipe and at a position from the water level of the suppression pool between the dry well and the suppression pool. The present invention is characterized by comprising a communication pipe communicating with the suppression pool interior space at a position higher than the height of the hydrostatic head corresponding to the differential pressure generated between the suppression pool and the suppression pool.

(Function) The present invention can reduce the volume of the suppression pool by the above-mentioned means, and also reduces the pressure rise in the dry well in the event that piping or equipment breaks in the dry well. becomes possible.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. Note that the same parts in FIG. 2 as in FIG. 1 are indicated by the same reference numerals, and the explanation of the overlapping parts will be omitted. Second
The difference between this figure and FIG. 1 lies in the installation of a communication pipe 14 that communicates the dry well 3 and the suppression pool 5.

FIG. 3 shows a partially enlarged view of the vicinity of this communication pipe 14. In this embodiment, the communication pipe 14 is connected to the dry well 3 side so that water 4 from the suppression pool 5 can flow into the dry well 3 in case the pressure on the dry well 3 side becomes lower than the pressure on the suppression pool 5 side. In order to prevent inflow, it is necessary to be located higher than the water level A of the suppression pool 5 by more than the static water head corresponding to the pressure difference between the dry well 3 and the suppression pool 5. This is dimension B in FIG. The communication pipe 14 on the suppression pool 5 side has a water depth C equivalent to that of the vent pipe 10 and a distance D from the bottom 9 of the suppression pool 5.

Next, the effects of the above embodiment will be explained. In the unlikely event that piping or equipment breaks in the dry well 3, the water in the suppression pool 5 that cooled the reactor pressure vessel 2 and the dry well 3 may accumulate in the bottom 9 of the dry well 3. can return to the suppression pool 5 from the communication pipe 14 before reaching the upper end of the vent pipe 10.

Therefore, it accumulates at the bottom of the dry well 3,
Water that does not contribute to subsequent cooling of the reactor pressure vessel 2 and dry well 3 is removed from the bottom 9 of the dry well 3.
As a result, the amount of water initially stored in the suppression pool 5 can be reduced. That is, the volume of the suppression pool 5 can be reduced.

In addition, since the communication pipe 14 is submerged in the water 4 of the suppression pool 5 under the same conditions as the vent pipe 10, in the event that piping or equipment breaks in the dry well 3, Since the communication pipe 14, like the vent pipe 10, can send the steam generated when the reactor coolant flows out to the suppression pool 5 and cool it, the pressure increase in the dry well 3 can be reduced. This has the effect of improving the integrity of the reactor containment vessel 1.

4 and 5 show other embodiments of the present invention, with FIG. 4 showing a Mark I type reactor containment vessel. Note that the same parts in the figure as in FIG. 2 are indicated by the same reference numerals, and the explanation of the overlapping parts will be omitted.

That is, as shown in FIG. 4, regardless of the type and shape of the reactor containment vessel 1, the dry well 3
If a portion of the suppression pool 5 is located below the water level A of the suppression pool 5, the same effect as the embodiment shown in FIG. 2 can be obtained by installing the communication pipe 14 according to the present invention.

[Effects of the Invention] As explained above, according to the reactor containment vessel of the present invention, it is possible to reduce the pressure increase in the dry well that would occur due to the unexpected breakage of piping, equipment, etc. within the dry well. Therefore, it is possible to improve the integrity of the reactor containment vessel, and also to reduce the amount of water in the suppression pool that accumulates at the bottom of the drywell, i.e., drawdown water, thereby reducing the volume of the suppression pool. It has the effect of

Furthermore, since the communication pipe can also be used as a vent pipe, the pressure inside the dry well can be reduced.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view partially diagrammatically showing a conventional reactor containment vessel, FIG. 2 is a vertical cross-sectional view partially schematically showing the reactor containment vessel of the present invention, and FIG. 2 is an enlarged vertical cross-sectional view showing the main parts of FIG. 2, and FIG. 4 is a vertical cross-sectional view showing another embodiment of the present invention. 1... Reactor containment vessel, 2... Reactor pressure vessel, 3... Dry well, 5... Suppression pool, 6... Pedestal, 7... Diaphragm floor, 10... Vent pipe, 11... Core cooling system pump, 12... Containment vessel spray system pump, 1
3...Containment vessel spray header, 14...Communication pipe, A...Water level in the suppression pool, B
...Height from the water level in the suppression pool to the dry well side of the communication pipe, C...Water depth of the communication pipe and vent pipe, D...The height from the outlet of the communication pipe and vent pipe to the bottom of the suppression pool. interval.

Claims (1)

[Claims] 1. The lower part of the dry well is located below the water level of the water stored in the suppression pool, and a number of vent pipes are provided to connect this dry well and the suppression pool. In the reactor containment vessel, the lower end opening is immersed in the suppression pool water, the upper end opening is at a position lower than the upper end opening position of the vent pipe, and the position from the suppression pool water level is at the position below the upper end opening position of the vent pipe. A nuclear reactor characterized by comprising a communication pipe communicating with the space inside the suppression pool at a position above the height of a static water head corresponding to the differential pressure generated between the dry well and the suppression pool. Containment vessel. 2. The reactor containment vessel according to claim 1, wherein the lower end opening of the communication pipe has the same water depth as the outlet of the vent pipe and a distance from the bottom of the suppression pool.