JPS59136681A - Two-chamber type reactor container - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a nuclear reactor containment vessel, and in particular, the interior thereof is divided into an upper dry well chamber and a lower dry well chamber, and the spaces can be further communicated. The present invention relates to a nuclear reactor containment vessel equipped with a dry well communication pipe equipped with a check device capable of closing a slag flow path.

[Prior art]

In conventional reactor containment vessels, there is no check device in the dry well connecting pipe, so in the event of a pipe rupture in the upper dry well space, high-temperature reactor water containing radioactivity will flow into the lower dry well through the dry well connecting pipe. do. The lower drywell does not have a device to cool high-temperature water, so the inflow water is kept at a high temperature.
It takes a long time for the internal pressure of the reactor containment vessel to drop, and if a bottle ball or the like is found on the wall of the reactor containment vessel, there is a drawback that radioactivity tends to leak to the outside for a long period of time.

The emergency core cooling system sucks the water stored in the suppression chamber and injects it into the reactor. After the injected water cools the core, it flows out of the fracture port and is released into the dry well. However, if it does not return to the suppression chamber and flows into the lower dry well, the water stored in the suppression chamber will decrease and the water level will drop. As a result, the pump thrust hydrostatic head (NPSH) of the emergency core cooling system becomes insufficient and the capacity of the heat exchanger for cooling the stored water increases.

[Purpose of the invention]

In the present invention, high-temperature reactor water or suppression chamber stored water pumped out by an emergency core cooling pump is transferred to the lower dry well by installing a reverse device in the dry well connecting pipe to close the flow from the upper dry well to the lower dry well. It is an object of the present invention to provide a reactor containment vessel that prevents water from flowing into a dry well and does not have the drawbacks of the prior art.

[Summary of the invention]

The present invention is characterized in that a check device is installed in the dry well communication pipe. Furthermore, the present invention has the effect of suppressing the rise in internal pressure of the reactor containment vessel in the event of a pipe rupture accident to a lower level than in the past.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention. This will be explained below using FIG.

The reactor 1 is installed inside a reactor containment vessel 2, and the inside of the reactor containment vessel 2 is further divided into an upper dry well chamber A, a lower dry well chamber B, and a pressure suppression chamber C. The spaces of the upper dry well chamber A and the lower dry well chamber B are connected through a dry well communication pipe 4. Further, the upper dry well chamber A and the pressure suppression chamber C are connected through a vent pipe 3, and the tip of the vent pipe 3 extends into the water stored in the pressure suppression chamber.

A backflow device 5 is installed in the dry well communication pipe 4, and if the pipe 6 in the upper dry well chamber A breaks and reactor water flows out, the check device 5 closes the flow path to the lower dry well chamber B. All of the high-temperature reactor water flowing out from the rupture port is guided into the storage water of the pressure suppression chamber C and cooled, thereby minimizing the rise in the internal pressure of the reactor containment vessel.

When the pipe 6 in the lower dry well chamber B breaks, a portion of the high-temperature reactor water that flows out evaporates into steam, passes through the dry well connection pipe 4, pushes the check valve 5 open, and passes through the upper dry well chamber A. The water is then led through the vent pipe 3 to the storage water tank in the pressure suppression chamber C, where it is cooled.

Reactor water that has not vaporized remains in the lower dry well chamber B, but the diameter of the piping in the lower dry well chamber B is at most 50 mm.
Even if a rupture occurs, the increase in the internal pressure of the reactor containment vessel 2 will be small.

The check device 5 has the same closing principle as a general check valve that closes under its own weight.

According to this embodiment, there is no inflow of high-temperature reactor water into the upper dry well chamber A and the lower dry well chamber B, so that the disadvantages of the prior art can be overcome. Further, according to this embodiment, the peak pressure inside the reactor containment vessel 2 can be lowered in the event of a pipe rupture accident, and safety can be improved. FIG. 2 is a diagram showing changes in the internal pressure of the reactor containment vessel 2 at the time of the maximum pipe rupture accident in the upper dry well chamber A. Curve A in Figure 2 shows the case without a check device, and the curve at the beginning shows the case with the check device.From this figure, it can be seen that the present invention can reduce the peak pressure inside the reactor containment vessel by about 25% in the event of an accident. .

The peak pressure in the reactor containment vessel at the time of a pipe rupture accident is approximately proportional to the initial amount of air in the drywell. This is because the air in the dry well is pushed into the fixed space C of the pressure suppression chamber by the reactor water that leaked out during a pipe rupture accident, and the pressure in space C increases as the space volume of spaces A and B, that is, the amount of air increases, reaches its peak value. becomes higher.

In the Fu invention, since the lower dry well and the upper dry well are closed with a check device, the amount of air pushed into the space C is only the air amount in the upper dry well A, and the internal pressure of the reactor containment vessel is lowered. Modification of the present invention There are many examples and applications, such as connecting a remote drive mechanism to the check device, changing the structure, etc., but all of them are covered by the scope of the claims.

〔Effect of the invention〕

According to the present invention, the increase in internal pressure of the reactor containment vessel in the event of a pipe rupture accident can be suppressed to a low level.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the present invention in detail, and FIG. 2 is a diagram for explaining one effect of the present invention. l... Nuclear reactor, 2... Reactor containment vessel, 3... Vent pipe, 4... Dry well communication pipe, 5... Check device, 6... Piping (representative example), 7... Distribution W (typical example)
, A...Upper dry well chamber, B...Lower dry well chamber, C...Pressure 1st figure ￥2 days/10/l)ρ/
riρOshin intoxication/Karikawa use Okeller mockery-bha,:

Claims (1)

[Claims] 1. Contains the reactor pressure vessel and connects the upper dry well chamber, lower dry well chamber, pressure suppression chamber that stores water at the bottom, and the upper dry well chamber and lower dry well chamber. A type 2 reactor containment vessel characterized by comprising a dry well communication pipe equipped with a check device.