JPH05142379A - Cooling system of nuclear power plant - Google Patents

Abstract

PURPOSE:To remove a decay heat in a reactor core stably even in case the fluctuation of a pool water level is generated, by composing to expand and contract a non-condensable gas vent pipe according to the water level of the pooling water in a suppresion chamber. CONSTITUTION:When a cooling water flowing out from a nuclear reactor pressure container flows in to a chamber 10 from the opening 3a of the suppresion chamber 10 by a cooling water losing accident, and the water level of a suppression pool water is raised, a float 16 attached to the small piping 15a of the movable part of a non-condensable gas vent pipe 11 is raised. The pipe 15a is also raised together with the float 16. Furthermore, when the lower end of the pipe 15a reaches to the lower end of a small piping 15b by the water level rising, the pipe 15b is also raised being pushed up by the bendings of the lower ends of the pipes 15a and 15b. In such a way, the pool water soaking length of the chamber 10 of the pipe 11 is maintained at a constant height. Consequently, a deterioration of the exhausting capacity of the non-condensable gas by the variation of the pool water soaking height of the chamber 10 of the pipe 11, that is, a deterioration of the removing function of a decay heat generated in the reactor core, can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling facility for a nuclear power plant.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings. FIG. 5 is a schematic diagram showing a conventional cooling facility for a nuclear power plant. Nuclear power plants are equipped with cooling equipment that removes decay heat generated from the core to the outside of the reactor containment vessel for a long time after the accident in case of accident such as loss of coolant. .. In FIG. 5, a reactor core 1 is housed in a reactor pressure vessel 2, and this reactor pressure vessel 2 is housed in a reactor containment vessel 3. A main steam pipe 4 and a water supply pipe 5 are connected to the reactor pressure vessel 2. The steam generated in the reactor pressure vessel is sent to a turbine (not shown) via the main steam pipe 4 to supply electric power, and further passes through a condenser (not shown) as cooling water to serve as a water supply pipe 5 It is configured to return more. A cooling water source 6 is arranged adjacent to the reactor containment vessel 3 and above the reactor core 1, and cooling water 6a is stored therein. A condensing cooler 7 is housed in the cooling water source 6.
A steam supply pipe 8 is connected to the condensing cooler 7 so that the steam generated in the core 1 at the time of reactor isolation can be connected to the main steam pipe 4
It is configured to be introduced into the condenser cooler 7 via the. A condensed water return pipe 9 is connected to the condensing cooler 7, and the other end of the condensed water return pipe 9 is connected to the reactor pressure vessel 2. A suppression chamber 10 is arranged inside the reactor containment vessel 3. The suppression chamber 10 has one end
A non-condensable gas vent pipe 11 is provided which opens into pool water (hereinafter referred to as suppression pool water) 10a stored in the suppression chamber and whose other end is connected to the condenser cooler 7. Further, the suppression chamber 10 is connected to a vent pipe 12 having one end opened in the suppression pool water 10a and the other end provided with an opening 3a in a space 13 of the reactor containment vessel 3.

When a coolant loss accident occurs in the cooling facility of the nuclear power plant having the above-mentioned structure, steam and non-condensed gas generated by decay heat in the reactor pressure vessel 2 are passed through the steam supply pipe 8. And is sent to the condensing cooler 7 installed in the cooling water source 6. The steam flowing into the condensing cooler 7 is cooled by the cooling water 6a and condensed to become condensed water. This condensed water is passed through the condensed water return pipe 9 to the reactor pressure vessel 2
Is refluxed in. The internal temperature of the reactor pressure vessel 2 is lowered by this recirculation, and the pressure and temperature in the nuclear reactor containment vessel 3 are also reduced with this reduction. The non-condensable gas led to the condensing cooler 7 together with the vapor may be accumulated in the condensing cooler 7 and temporarily deteriorate the condensing performance of the condensing cooler 7.
By the way, the non-condensable gas vent pipe 11 has a shorter water immersion length than the vent pipe 12. Therefore, due to temporary deterioration of the vapor condensation performance in the condenser cooler 7, the reactor containment vessel 3
The temperature of the dry well 13, which is the space portion, rises, and the pressure also rises accordingly. Therefore, the water in the non-condensable gas vent pipe 11 is discharged before the vent pipe 12, and the non-condensable gas accumulated in the condensing cooler 7 is not condensed.
It is guided into the suppression chamber 10 via the and is discharged to the suppression chamber space 10b.

Although the steam supply pipe and the condensed water return pipe are directly connected to the reactor pressure vessel in FIG. 5, these pipes are connected to the reactor containment vessel to generate steam in the reactor core. The same cooling function is provided even in the case where it is configured to be guided to the condensing cooler via the reactor containment vessel.

[0005]

As described above, in the conventional cooling equipment of a nuclear power plant, the condensation cooler cools the steam generated in the core, and the condensed water is returned to the reactor pressure vessel. It is designed to remove decay heat. Accumulation of non-condensable gas, which hinders cooling by the condensation cooler, is released to the space inside the suppression chamber via the non-condensable gas vent pipe, thereby solving the problem.

Therefore, the cooling equipment needs to be designed so as to cope with any pipe breakage. That is, it is necessary to make the suppression pool flooded part of the non-condensable gas vent pipe deep to some extent so as not to be exposed even if the pool water level changes due to a loss of coolant. By the way, depending on the breakage position of the pipe, it is conceivable that part of the coolant flowing out of the reactor pressure vessel will flow into the suppression chamber and the water level of the suppression pool will rise. At this time, the part of the non-condensable gas vent pipe where the suppression pool is flooded becomes deeper as the suppression pool water level rises. As a result, the ability to discharge non-condensable gas may deteriorate, and the function of removing decay heat generated from the core may deteriorate.

The present invention has been made in view of the above problems, and it is possible to stably remove decay heat generated in the core over a long period of time even when the suppression pool water level fluctuates. The purpose is to provide cooling equipment for a power plant.

[0008]

In order to achieve the above object, the present invention provides a reactor pressure vessel for accommodating a core, a reactor containment vessel for accommodating the reactor pressure vessel, and a reactor containment vessel. A cooling water source that is adjacent to the core and that stores cooling water inside the core, a condensing cooler that is housed in the cooling water source, and a suppression that is arranged below the cooling water source and that stores pool water. A chamber, a steam supply pipe connecting the condensing cooler to the reactor pressure vessel and the dry well of the reactor containment vessel, and condensing the condensate water cooled by the condensing cooler to the reactor pressure vessel. A water return pipe, a vent pipe that connects the reactor containment vessel and the suppression chamber, and a non-condensable gas that guides the non-condensable gas accumulated in the condensation cooler to the suppression chamber. In nuclear power plant cooling system formed by and a cement pipe, characterized by a telescopic accordance with the non-condensible gas vent pipe water level of the pool water in the suppression chamber.

Further, in the cooling facility of the nuclear power plant, a space lower than the suppression chamber is provided in the suppression chamber with a pool water part and a space part in which the vent pipe and the non-condensable gas vent pipe are submerged. It is characterized by providing a weir of height.

[0010]

In the cooling facility of the nuclear power plant configured as described above, at the time of a cooling water loss accident, it is possible to expand or contract in accordance with the rise of the water level in the suppression pool due to the coolant flowing out from the breakage opening of the reactor containment vessel. The water level on the side connected to the pool water in the condensable gas vent pipe also rises. Further, when the weir is stored in the suppression chamber, the suppression pool water overflows when the suppression pool water exceeds the weir, so the water level of the suppression pool does not exceed the height of the weir. Therefore, the suppression pool water immersion length of the non-condensable gas vent pipe is maintained at a constant height, and deterioration of the non-condensable gas discharge capacity, that is, deterioration of the function of removing decay heat generated in the core is prevented. It will be possible.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are schematic views of cooling equipment of a nuclear power plant according to a first embodiment of the present invention. In the figure,
The same parts as those in FIG. 5 are denoted by the same reference numerals, and the description of the overlapping parts will be omitted. In FIG. 1, adjacent to the reactor containment vessel,
A cooling water source 6 is disposed above the core, and cooling water 6a is stored in this. In the cooling water source 6,
A condenser cooler 7 is stored. A steam supply pipe 8 is connected to the condensing cooler 7, and the steam generated in the core 1 at the time of reactor isolation is guided into the condensing cooler 7 via the main steam pipe 4. A condensed water return pipe 9 is connected to the condensing cooler 7, and the other end of the condensed water return pipe 9 is connected to the reactor pressure vessel 2. A suppression chamber 10 is arranged inside the reactor containment vessel 3. The suppression chamber 10 is provided with a non-condensable gas vent pipe 11 having one end opening into the suppression pool water 10 a stored in the suppression chamber 10 and the other end connected to the condenser / cooler 7. Further, one end of the suppression chamber 10 opens into the suppression pool water 10a, and the other end opens into the containment vessel 3
A vent pipe 12 having an opening 3a is connected to the space 13 of the above. Here, the non-condensable gas vent pipe 11 can expand and contract according to the water level of the suppression pool water.

FIG. 2 is a schematic view showing the structure of the non-condensable gas vent pipe 21 shown in FIG. Non-condensable gas vent pipe
Reference numeral 21 denotes a partial pipe 14 connected to the condensing cooler 7 and a plurality of small pipes joined so as to surround the outer periphery of the partial pipe 14 one after another.
It is composed of 15a, 15b, 15c and a float 16 adhered to the outermost small pipe 15a. Here, the lower end of the partial pipe 14 is bent outward, the upper ends of the small pipes 15b and 15c are bent inward, and the lower end is bent outward. Outermost small piping 15
In a, both ends are bent inward. These bends contribute to the prevention of the drop of the small pipe due to gravity and the smooth operation of the small pipe.

According to the cooling facility of the nuclear power plant configured as described above, the coolant flowing out of the reactor pressure vessel due to the loss of coolant is prevented from flowing into the suppression chamber opening portion 3.
When the water flows into the suppression chamber 10 from a and the water level of the suppression pool rises, the float 16 rises and the small pipe 15a rises. Small piping due to rising water level 15
When the lower end of a reaches the lower end of the small pipe 15b, the small pipe 15a,
It is pushed up by the bend at the lower end of 15b, and the small pipe 15b also rises.

Since the movable part of the non-condensable gas vent pipe 11 contracts according to the suppression pool water level in this way, the pool water immersion length of the suppression chamber 10 of the non-condensable gas vent pipe is maintained at a constant height. Therefore, the discharge capacity of the non-condensable gas is deteriorated by the change in the pool water immersion length of the suppression chamber 10 of the non-condensable gas vent pipe 11 due to the fluctuation of the water level of the suppression pool water 10a, that is, the decay heat generated in the core is removed. It is possible to prevent the deterioration of the function.

Next, FIGS. 3 and 4 are schematic views of the cooling equipment of the nuclear power plant according to the second embodiment of the present invention. In addition,
In the figure, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description of the overlapping parts is omitted. In FIG. 3, a weir 17 having a height lower than that of the suppression chamber 10 is provided in the suppression chamber 10, one of which holds pool water 10a and a non-condensable gas vent pipe 11 is introduced to the other space 10b.
The pool is configured to store overflowing pool water 10a over the weir 17.

According to the cooling facility of the nuclear power plant configured as described above, in the case of the loss of coolant accident, as shown in FIG. 4, the coolant flowing out of the reactor pressure vessel due to the loss of coolant accident is From the suppression chamber opening 3a,
When it flows into the suppression chamber 10 and the water level of the suppression pool water 10a rises and exceeds the weir 31, the suppression pool water 10a overflows and the suppression pool
It flows into 10 spaces 10b.

Therefore, the pool water immersion length of the non-condensable gas vent pipe 11 is suppressed to a certain value or less, and deterioration of the non-condensable gas discharge capacity, that is, deterioration of the function of removing decay heat generated in the core is prevented. can do.

[0019]

According to the present invention, the pool water immersion length is kept constant in the suppression chamber of the non-condensable gas vent pipe in the function of removing the decay heat of the core after the cooling water loss accident using the condensing cooler. Since it is possible to prevent deterioration of the removal function due to fluctuations in the suppression pool water surface,
The safety of the reactor can be significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing cooling equipment of a nuclear power plant according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a non-condensable gas vent pipe according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing cooling equipment of a nuclear power plant according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of a suppression chamber according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram showing a cooling facility of a conventional nuclear power plant.

[Explanation of symbols]

 1 ... Reactor core 2 ... Reactor pressure vessel 3 ... Reactor containment vessel 3a ... Opening portion 4 ... Main steam pipe 5 ... Water supply pipe 6 ... Cooling water source 6a ... Cooling water 7 ... Condensing cooler 8 ... Steam supply pipe 9 ... Condensing water Return pipe 10 ... Suppression chamber 10a ... Suppression pool water 11 ... Non-condensable gas vent pipe 12 ... Vent pipe 13 ... Space part 14 ... Partial pipe 15a, 15b, 15c ... Small pipe 16 ... Float 17 ... Weir

Claims (2)

[Claims] 1. A reactor pressure vessel for accommodating a core, a reactor containment vessel for accommodating the reactor pressure vessel, and a cooling water provided inside the reactor vessel adjacent to the reactor vessel and above the core. A cooling water source to be stored, a condensing cooler housed in the cooling water source, a suppression chamber arranged under the cooling water source to store pool water, the condensing cooler, the reactor pressure vessel and the atom. A steam supply pipe connecting the dry well of the reactor containment vessel, a condensed water return pipe returning the condensed water cooled by the condensation cooler to the reactor pressure vessel, and connecting the reactor containment vessel and the suppression chamber. And a non-condensable gas vent pipe for guiding the non-condensable gas accumulated in the condensation cooler to the suppression chamber. The non-condensable gas vent pipe is expandable / contractible according to the water level of pool water in the suppression chamber. 2. A reactor pressure vessel for accommodating a core, a reactor containment vessel for accommodating the reactor pressure vessel, and a cooling water inside which is disposed adjacent to the reactor containment vessel and above the core. A cooling water source to be stored, a condensing cooler housed in the cooling water source, a suppression chamber arranged under the cooling water source to store pool water, the condensing cooler, the reactor pressure vessel and the atom. A steam supply pipe connecting the dry well of the reactor containment vessel, a condensed water return pipe returning the condensed water cooled by the condensation cooler to the reactor pressure vessel, and connecting the reactor containment vessel and the suppression chamber. And a non-condensable gas vent pipe for guiding the non-condensable gas accumulated in the condensation cooler to the suppression chamber. And a weir having a height lower than that of the suppression chamber is provided in the suppression chamber by separating a pool water portion into which the vent pipe and the non-condensable gas vent pipe are submerged and a space portion. Cooling equipment.