JP3125596B2 - Emergency core cooling equipment for nuclear reactors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency core cooling system for a nuclear reactor.

[0002]

2. Description of the Related Art In a nuclear reactor, for example, an extremely low probability (virtual accident) that a main steam pipe breaks and injection of emergency core cooling water into the core also fails will occur. In this case, as a conventional device, Japanese Patent Laid-Open No. 5-142
As described in No. 380, there is a method in which the coolant in the suppression chamber is injected into the downcomer of the pressure vessel using the pressure difference between the inside and outside of the containment vessel in the event of a virtual accident.

[0003]

In the above prior art, sufficient consideration was not given to efficient cooling of the internal structure of the pressure vessel and the damaged core in the event of a virtual accident, and the prior art flowed out of the pressure vessel into the containment vessel. The amount of internal structural materials and the damaged core increases, and the amount of non-condensable gas generated by the reaction of the containment with the floor concrete increases. However, there is a problem that it is necessary to take measures such as increasing the height of the steel or installing a core catcher for suppressing the reaction with the floor concrete.

A first object of the present invention is to efficiently cool a dryer, a shroud and a damaged core inside a pressure vessel, and to suppress the amount of internal structural material and the damaged core flowing out of the pressure vessel to the containment vessel. The object is to eliminate the need for special measures to maintain the integrity of the containment vessel.

[0005] A second object of the present invention, in addition to the first object, makes it possible to suppress the amount of internal structural material and damaged core flowing out of the pressure vessel into the containment vessel without human operation. It is in.

A third object of the present invention, in addition to the first object or the second object, is to uniformly cool a drier and a shroud inside a pressure vessel, and to provide an internal structural material flowing out of the pressure vessel to a containment vessel, and Another object of the present invention is to further reduce the amount of a damaged core.

A fourth object of the present invention, in addition to the first object, the second object, or the third object, is to efficiently cool a structure in the pressure vessel so that the pressure vessel moves from the pressure vessel to the containment vessel. Another object of the present invention is to further reduce the amount of internal structural material and damaged core flowing out.

[0008]

A first means comprises a pressure vessel containing a core, a containment vessel containing the pressure vessel,
A first pipe for supplying a coolant to an upper head of the pressure vessel, a pool of coolant installed outside the containment vessel, and a supply pipe for supplying coolant in the pool to the first pipe; Supplying a coolant to the upper head in an emergency core cooling facility for a nuclear reactor having a second pipe provided and a pump provided in the second pipe and supplying a coolant of the pool to the pressure vessel. A first valve and a second valve provided in the first pipe, a third valve provided in the second pipe, and a third valve provided between the first valve and the second valve. The second pipe connected to one pipe portion, and at least the water level of the pressure vessel falls below a predetermined position, or the temperature of a pedestal section in the containment vessel rises above a predetermined value, and The flow rate of the emergency core cooling system that fills the pressure vessel A control means for activating the pump provided in the second pipe, closing the second valve, and opening the first valve and the third valve, This is an emergency core cooling facility for nuclear reactors.

[0009]

The second means is the first means, wherein a weir forming a pool of coolant is formed on a peripheral portion of an upper surface of an upper shroud inside the pressure vessel, and the weir is provided on the weir and distributed along the circumference. An emergency core cooling system for a nuclear reactor, comprising a plurality of flow passage holes through which a coolant flows out.

[0011] The third means is a pressure vessel containing a core,
A containment vessel containing the pressure vessel, a first pipe for supplying a coolant to an upper head of the pressure vessel, a coolant pool installed outside the containment vessel, and a coolant in the pool. The second contacted to supply to the first pipe
In an emergency core cooling system of a nuclear reactor having a pipe and a pump provided in the second pipe and supplying a coolant of the pool to the pressure vessel, below the upper shroud inside the pressure vessel, An emergency core cooling system for a nuclear reactor, comprising a structural material for guiding a coolant flowing down a side surface of an upper shroud toward a center of the pressure vessel.

The fourth means is the first means or the second means , wherein the coolant flowing down the side surface of the upper shroud is provided below the upper shroud inside the pressure vessel toward the center of the pressure vessel. An emergency core cooling system for a nuclear reactor, comprising a structural material for guiding.

A fifth means is a pressure vessel containing a core,
A containment vessel containing the pressure vessel, a first pipe for supplying a coolant to an upper head of the pressure vessel, a coolant pool installed outside the containment vessel, and a coolant in the pool. The second contacted to supply to the first pipe
In the emergency core cooling equipment of a nuclear reactor having a pipe and a pump provided in the second pipe and supplying a coolant of the pool to the pressure vessel, on an upper surface of an upper shroud inside the pressure vessel, A third pipe communicating between an upper part and a lower part of the upper shroud, and a valve plugged with a metal that melts when a temperature exceeds a predetermined value at an opening of the third pipe. This is an emergency core cooling system for a nuclear reactor.

A sixth means according to any one of the first means to the fourth means , wherein a third pipe communicating between the upper part and the lower part of the upper shroud is provided on the upper surface of the upper shroud inside the pressure vessel. An emergency core cooling system for a nuclear reactor, comprising: a valve plugged with a metal that melts when the temperature exceeds a predetermined value at an opening of the third pipe.

[0015]

According to the first means, in the event of a virtual accident in which a part of the reactor core flows below the pressure vessel, the coolant is pumped from the pool outside the reactor containment vessel to the upper head of the pressure vessel. Supplied. Coolant from the pool outside the containment vessel is supplied to the upper head of the pressure vessel through a second pipe and a first pipe that supplies coolant to the upper head. The coolant supplied into the pressure vessel flows down from the upper head of the pressure vessel to cool the internal components in the pressure vessel.

More specifically, the cooling agent supplied to the upper head flows down in contact with the dryer, and then spreads on the upper surface of the upper shroud and flows down from the side surface of the upper shroud. . During this time, the heat of the dryer and the upper shroud is transferred to the coolant, and a part of the coolant evaporates and the temperature of the dryer and the upper shroud decreases.

Further, the coolant flows down the shroud from the lower part of the separator provided on the outer peripheral part of the pressure vessel. During this time, the temperature of the lower part of the separator and the shroud is reduced by the coolant, and the heat of the damaged core remaining in the pressure vessel is transmitted to the coolant through the shroud, so that the damaged core is also cooled. Finally, the coolant flows into the lower plenum and flows out of the break into the containment. During this time, heat in the lower plenum and the damaged core remaining in the lower plenum is transferred to the coolant, and the temperature decreases. As described above, the dryer, shroud and damaged core inside the pressure vessel are efficiently cooled, and the amount of the internal structural material and the damaged core that melts and flows out of the pressure vessel into the containment vessel is suppressed. The amount of non-condensable gas generated by reaction with concrete decreases, and the pressure resistance of the containment vessel is increased to maintain the integrity of the containment vessel, and a core catcher that suppresses the reaction with floor concrete is installed. There is no need to take countermeasures. In addition, according to the first means, the control means determines that at least the water level of the pressure vessel drops below a predetermined position, or the temperature of the pedestal section in the containment vessel rises above a predetermined value, and When the flow rate of the emergency core cooling system for injecting water into the vessel is smaller than a predetermined value, the pump installed in the second pipe is started, the second valve is closed, and the first valve is closed.
And the third valve are opened, so that at the time of a virtual accident, at least the water level of the pressure vessel falls below a predetermined position, or the temperature of the pedestal section in the containment vessel rises above a predetermined value. If the flow rate of the emergency core cooling system for injecting water into the pressure vessel is smaller than a predetermined value, the pump installed in the second pipe is started by the control device, and the second
Are closed, and the first and third valves are opened. Thereby, the coolant of the second water pool is supplied to the upper head of the pressure vessel through the second pipe and the pipe for supplying the coolant to the upper head, and the cooling supplied to the upper head of the pressure vessel. The material effectively cools the components inside the pressure vessel and reduces the amount of internal structural material and damaged core flowing out of the pressure vessel to the containment vessel, but this is possible without human operation.

[0018]

According to the second means , in addition to the action of the first means, at the time of a virtual accident, the coolant supplied from the upper head of the pressure vessel to the inside of the pressure vessel causes the upper surface of the upper shroud to rise. Spreading out, a water pool is formed on the upper surface of the upper shroud, and the upper surface of the upper shroud is uniformly cooled. Further, the weir is provided with a large number of flow openings for letting out the coolant, and the coolant flows out so as to be substantially uniform in the circumferential direction by the hydrostatic head. Thereby, the side surface of the upper shroud is also cooled uniformly. By uniformly cooling the upper shroud, which is the internal structure of the pressure vessel, the amount of the internal structure and the damaged core flowing out of the pressure vessel to the containment vessel is further reduced.

According to the third means , in the event of a virtual accident where a part of the reactor core flows below the pressure vessel, coolant is pumped from the pool outside the reactor containment vessel to the upper head of the pressure vessel. Supplied. Coolant from the pool outside the containment vessel is supplied to the upper head of the pressure vessel through a second pipe and a first pipe that supplies coolant to the upper head. The coolant supplied into the pressure vessel flows down from the upper head of the pressure vessel to cool the internal components in the pressure vessel. In addition, at the time of a virtual accident, the coolant supplied from the upper head of the pressure vessel to the inside of the pressure vessel flows down from the side of the upper shroud. At this time, since the coolant flows down along the structural material leading toward the center of the pressure vessel, the amount of the coolant flowing down from the upper shroud to the components below in a liquid film state increases, and the amount of coolant in the pressure vessel increases. By cooling the internal structure efficiently, the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is further suppressed.

According to the fourth means , the first means or the second means
In addition to the action of the steps , coolant supplied from the upper head of the pressure vessel into the interior of the pressure vessel flows down the sides of the upper shroud. At this time, since the coolant flows down along the structural material leading toward the center of the pressure vessel, the amount of the coolant flowing down from the upper shroud to the components below in a liquid film state increases, and the amount of coolant in the pressure vessel increases. By cooling the internal structure efficiently, the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is further suppressed.

According to the fifth means , in the event of a virtual accident in which a part of the reactor core flows below the pressure vessel, coolant is pumped from the pool outside the reactor containment vessel to the upper head of the pressure vessel. Supplied. Coolant from the pool outside the containment vessel is supplied to the upper head of the pressure vessel through a second pipe and a first pipe that supplies coolant to the upper head. The coolant supplied into the pressure vessel flows down from the upper head of the pressure vessel to cool the internal components in the pressure vessel. In addition, when the temperature of the core rises during a virtual accident, the temperature of the plug installed in the third pipe also rises due to radiant heat and convective heat transfer. When the temperature of the stopper melts above the melting temperature,
The coolant supplied from the upper head of the pressure vessel to the inside of the pressure vessel through the third pipe is also supplied to the inside of the structure in the pressure vessel and flows down.

According to the sixth means , in addition to the operation of any one of the first means to the fourth means, when the temperature of the reactor core rises during a virtual accident, the radiant heat and convective heat transfer are performed. The temperature of the plug installed in the third pipe also increases. When the temperature of the stopper melts above the melting temperature, the coolant supplied from the upper head of the pressure vessel to the inside of the pressure vessel through the third pipe is also supplied to the inside of the structure in the pressure vessel and flows down. I do.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a configuration to which the present invention is applied will be described with reference to FIGS.

FIG. 1 is a sectional view of a boiling water reactor, in which a reactor core 1 is surrounded by a pressure vessel 2, and the pressure vessel 2 is contained inside a containment vessel 3.

As a system for purifying the coolant during normal operation, a valve 23 and an intermediate heat exchanger are connected to a pipe 10 for extracting the coolant from the downcomer 6 and supplying the coolant to the upper head of the pressure vessel 2. 50, pump 41, filtration desalination device 5
1, a valve 20, and a valve 21 are provided.

A valve 24 is installed on the pipe 12 branched from the pipe 10, and the other end of the pipe 12 is connected between the check valves 25 and 26 of the water supply pipe 15.

The feature of this embodiment is that the water pool 30 is installed outside the containment vessel 3 and the water pool 30 and the valve 2
And a pipe 11 for connecting between the valve 11 and the valve 21.
To have the valve 22 and the pump 40.

As the water pool 30 and the pump 40, a filtered water tank and a fire extinguishing system pump or a condensate storage tank and a condensate makeup water system pump which are existing facilities may be used.

In such a nuclear reactor, it is assumed that an extremely low probability event that, for example, the main steam pipe 4 breaks and the injection of the emergency core cooling water into the core 1 fails also occurs. Then, the temperature of the core 1 rises due to the decay heat and is melted, and a part thereof accumulates at the lower end of the pressure vessel 2.

Here, assuming that the core 1 could not be cooled, a part of the core 1 falls to the pedestal part 5 from the lower end of the pressure vessel 2.

The occurrence of such a situation can be determined from a decrease in the water level in the pressure vessel, the presence or absence of the flow rate of the emergency core cooling water, an increase in the temperature of the pedestal portion in the containment vessel, and the like.

When such a situation is assumed, the pump 40 is started by manual operation or remote automatic operation, the valve 21 is closed, and the valves 20 and 22 are opened.

Thus, the coolant in the water pool 30 is supplied to the upper head of the pressure vessel 2 through the pipes 11 and 10.

The water injection flow rate is preferably a flow rate suitable for removing decay heat from the damaged core, that is, 60 t / h or more in the case of a nuclear power plant having an electric output of 135 MWe.

The function of the coolant inside the pressure vessel 2 is indicated by arrows in FIG. 2 and will be described below.

The coolant sprayed from the upper head of the pressure vessel 2 to the inside of the pressure vessel first flows down in contact with the dryer 60, further spreads on the upper surface of the upper shroud 61, and flows down from the side surface of the upper shroud 61.

During this time, the dryer 60 and the upper shroud 6
The heat of 1 is transmitted to the coolant, and a part of the coolant evaporates, and the temperatures of the dryer 60 and the upper shroud 61 decrease.

Further, the coolant flows down the shroud 63 from the separator 62 provided on the outer periphery of the pressure vessel.

During this time, the temperature of the lower part of the separator 62 and the shroud 63 is reduced by the coolant, and the heat of the damaged core 101 remaining in the pressure vessel 2 is transmitted to the coolant through the shroud 63, and the damaged core 101 is also cooled. Cooled.

Finally, the coolant is supplied to the internal pump 66.
It flows into the lower plenum 64 through the opening in the nearby shroud support and out of the pressure vessel 2 through the break 65.

During this time, the heat of the damaged plenum remaining in the lower plenum 64 and the lower plenum is transferred to the coolant, and the temperature is reduced.

As described above, the dryer 6 inside the pressure vessel 2
0, the upper shroud 61, the damaged core 101, the shroud 63, and the damaged core 102 are efficiently cooled, and the amount of the internal structural material and the damaged core that melt and flow out of the pressure vessel 2 is suppressed.

Immediately after the pressure vessel breaks, within 1 hour as a guide, if water is injected, the amount of the internal structural material and the damaged core flowing out of the pressure vessel 2 will be about 4 times that when no water is injected.
0% reduction.

As a result, the core-concrete reaction in the containment vessel quickly converges, and the amount of non-condensable gas generated is reduced by about 40%. Therefore, it is not necessary to take measures such as increasing the pressure resistance of the containment vessel and installing a core catcher for suppressing the reaction with the floor concrete in order to maintain the performance.

According to this embodiment, the dryer, the shroud and the damaged core inside the pressure vessel are efficiently cooled, so that the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is suppressed. This has the effect of eliminating the need for special measures for maintaining the integrity of the containment vessel.

In the first embodiment of the present invention, as shown in FIG. 3, a control-related configuration is added to the configuration of FIG. 1 to which the present invention is applied.

The difference from the example shown in FIG.
The point is that a valve operating device 80, a valve operating device 81, a valve operating device 82, and a pump operating device 83 are additionally provided.

Whether at least the water level in the pressure vessel 2 drops to a predetermined value, for example, 3 m below the upper end of the core 1,
Alternatively, if the temperature of the pedestal unit 5 in the containment vessel 3 rises to a predetermined value, for example, 350 ° C., and the flow rate of the emergency core cooling system ECCS is smaller than a predetermined value, for example, 60 t / h, the control is performed. The device 70 sends a signal to start the pump 40 to the pump operation device 83, a signal to close the valve 21 to the valve operation device 81, and a signal to open the valve 20 to the valve operation device 80.
To the valve operating device 82.

In such a nuclear reactor, it is assumed that an extremely low probability event that, for example, the main steam pipe 4 breaks and the injection of the emergency core cooling water into the core 1 fails also occurs. Then, the temperature of the core 1 rises due to the decay heat and is melted, and a part thereof accumulates at the lower end of the pressure vessel 2.

Here, assuming that the core 1 could not be cooled, a part of the core 1 falls from the lower end of the pressure vessel 2 to the pedestal part 5.

At this time, at least the water level in the pressure vessel falls below a predetermined value of 3 m below the upper end of the core 1, or the temperature of the pedestal section 5 in the containment vessel 3 becomes lower than the predetermined value of 350 ° C. When the flow rate of the emergency core cooling system ECCS rises and is smaller than a predetermined value of 60 t / h, the controller 70 sends a signal for starting the pump 40 to the pump operation device 83 and a signal for closing the valve 21. To the valve operating device 81, and a signal for opening the valve 20 to the valve operating device 80,
A signal for opening the valve 22 is sent to the valve operating device 82.

Thus, the coolant in the water pool 30 is supplied to the upper head of the pressure vessel 2 through the pipes 11 and 10.

The dryer, the upper shroud, the shroud, and the damaged core inside the pressure vessel 2 are efficiently cooled by the coolant supplied from the upper head of the pressure vessel to the inside of the pressure vessel, and melted out of the pressure vessel 2. The amount of outflowing internal structural materials and damaged cores is reduced.

Immediately after the pressure vessel breaks, within 1 hour as a guide, if water is injected, the amount of the internal structural material and the damaged core flowing out of the pressure vessel 2 becomes about 4 times that when no water is injected.
0% reduction.

As a result, the core-concrete reaction in the containment quickly converges, and the amount of non-condensable gas generated is reduced by about 40%. Therefore, it is not necessary to take measures such as increasing the pressure resistance of the containment vessel and installing a core catcher for suppressing the reaction with the floor concrete in order to maintain the performance.

In this embodiment, the operation of the valve and the pump is automated by the control device, the dryer, the shroud and the damaged core inside the pressure vessel are efficiently cooled, and the internal structural material flowing out of the pressure vessel to the containment vessel and the damaged There is an effect that the amount of the core can be suppressed without depending on human operation.

An example of another configuration to which the present invention is applied will be described with reference to FIG.

An example of this configuration is an example of a nuclear power plant having a jet pump 8 different from the example shown in FIG.

In this plant, the coolant is extracted from the water pool 7 in the suppression chamber when the reactor is isolated, etc.
A pipe 28 for supplying coolant to the upper head of
A steam-driven pump 42, a check valve 27, and a valve 20 are provided.

A water pool 30 is installed outside the containment vessel 3, and a pipe 11 for connecting the water pool 30 with the valve 20 of the pipe 13 and the check valve 27 is provided. And

In such a reactor, it is assumed that, for example, a very low probability event that the main steam pipe 4 breaks and the injection of the emergency core cooling water into the core 1 fails also occurs. Then, the temperature of the core 1 rises due to the decay heat and is melted, and a part thereof accumulates at the lower end of the pressure vessel 2.

Here, assuming that the core 1 could not be cooled, a part of the core 1 falls to the pedestal section 5 from the lower end of the pressure vessel 2.

The occurrence of such a situation can be determined from the drop in the water level in the pressure vessel, the presence or absence of the flow rate of the emergency core cooling water, the rise in the temperature of the pedestal section in the containment vessel, and the like.

When such a situation is assumed, the pump 40 is started by manual operation or remote automatic operation, and the valve 20 is opened.

Thus, the coolant in the water pool 30 is supplied to the upper head of the pressure vessel 2 through the pipes 11 and 13.

The water injection flow rate is preferably a flow rate suitable for removing decay heat from the damaged core, that is, 50 t / h or more in the case of a nuclear power plant having an electric output of 110 MWe.

The dryer, the upper shroud, the shroud, and the damaged core inside the pressure vessel 2 are efficiently cooled by the coolant supplied from the upper head of the pressure vessel to the inside of the pressure vessel, and melted out of the pressure vessel 2. The amount of the internal structure material and the damaged core flowing out is suppressed as in the case of the embodiment shown in FIG.

Immediately after the pressure vessel breaks, the amount of the internal structural material and the damaged core flowing out of the pressure vessel 2 can be reduced by about 4 hours as compared with the case without water injection.
0% reduction.

As a result, the core-concrete reaction in the containment quickly converges, and the amount of non-condensable gas generated is reduced by about 40%. Therefore, it is not necessary to take measures such as increasing the pressure resistance of the containment vessel and installing a core catcher for suppressing the reaction with the floor concrete in order to maintain the performance.

According to the example of this configuration, even in a plant having a jet pump, the internal structural material flowing out of the pressure vessel to the containment vessel in order to efficiently cool the dryer, shroud and damaged core inside the pressure vessel. In addition, the amount of the damaged core is suppressed, and there is an effect that special measures for maintaining the integrity of the containment vessel are not required.

A second embodiment of the present invention will be described with reference to FIG.

In this embodiment, the inside of the pressure vessel 2 is to be cooled more efficiently in the example shown in FIG. 1 or FIG.

A weir 90 that forms a water pool at the outer periphery of the upper surface of the upper shroud 61 that supports the lower part of the dryer 60 inside the pressure vessel 2 and surrounds the separator 62, and a number of flow passage holes 91 through which the coolant flows out to the weir 90 Having.

Further, below the upper shroud 61, there is provided a structural member 92 for guiding the coolant flowing down the side surface of the upper shroud 61 toward the center of the pressure vessel 2.

Further, a structural material 93 is provided in the shroud 63 so that the coolant flows down the shroud 63 without fail.

In such a reactor, the coolant sprayed from the upper head of the pressure vessel 2 into the interior of the pressure vessel at the time of a hypothetical accident first contacts the dryer 60 and flows down. The upper shroud 61
Is accumulated on the upper surface of the liquid to form a liquid level.

As an example of the design, the flow rate of the coolant is 60 t
/ H, the height of the weir 90 is 5 cm, the diameter of the channel hole 91 is 2 cm,
Assuming that the number is 100, the coolant forms a water level of about 5 cm on the upper shroud 61, and the coolant is substantially uniform in the circumferential direction on the side surface of the upper shroud 61 through the flow passage hole 91. Leaked to

As a result, the upper part and the side part of the upper shroud 61 are uniformly cooled, and the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is further suppressed.

Further, the coolant travels through the structure 92 provided below the upper shroud 61 and flows down from the lower part of the separator 62 provided on the outer periphery of the pressure vessel to the shroud 63.

The coolant that has flowed down to the shroud 63 is transmitted through the structural material 93, and flows down the shroud 63 further down in a liquid film state.

As a result, the lower part of the separator 62 and the shroud 63 are also cooled uniformly, and the amount of the internal structural material and the damaged core flowing out of the pressure vessel into the containment vessel is reduced by about 50% as compared with the case where no water is injected.

In the embodiment shown in FIG. 4, it goes without saying that the inside of the pressure vessel 2 can be cooled more efficiently by taking the same measures.

According to this embodiment, the dryer and the shroud inside the pressure vessel are uniformly cooled, and the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is further suppressed.

A third embodiment of the present invention will be described with reference to FIGS.

In this embodiment, a pipe 94 communicating vertically between the upper shroud 61 and the pressure vessel 2 is provided below the pipe 94 in the example shown in FIG. 1, FIG. 3 or FIG.
There is provided a valve in which a plug 95 is stopped by a metal 99, for example, lead and bolts 96 and nuts 97 and nuts 98, which melts when the inside exceeds a predetermined value, for example, 328 ° C.

With such a reactor, the same cooling effect as in the example of FIG. 1 can be obtained.

In addition, when the temperature of the reactor core rises during a hypothetical accident, the separator 62 is radiated and convectively transferred by heat.
Temperature also rises.

Further, the radiant heat and convective heat transfer from the separator 62 cause the metal 9
The temperature of 9 also rises.

When the temperature of the metal 99 exceeds the melting temperature, the plug 95 falls downward and passes through the pipe 94 to the upper shroud 6.
The upper and lower sides of 1 communicate.

The coolant supplied from the upper head of the pressure vessel 2 to the inside of the pressure vessel 2 first flows down in contact with the dryer 60, and flows down to the upper part of the separator 62 through the pipe 94.

[0092] The coolant flowing down to the upper part of the separator 62 passes through the separator 62 and further to the damaged core (not shown).
It also flows down to the top.

Thus, the separator 6 inside the pressure vessel
2 is also cooled efficiently, and the amount of internal structural material and damaged core flowing out of the pressure vessel 2 is further suppressed.

According to the present embodiment, the separator inside the pressure vessel is also cooled efficiently, and the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is further suppressed.

[0095]

According to the first aspect of the present invention, in the event of a virtual accident, the equipment inside the pressure vessel and the damaged core are efficiently cooled, and the amount of the internal structural material and the damaged core flowing out of the pressure vessel to the containment vessel. And the need for special measures to maintain the integrity of the containment vessel is eliminated, and reducing the amount of internal structural material and damaged core flowing out of the pressure vessel to the containment vessel is a human operation. Independent effects can be obtained.

[0096]

According to the invention of claim 2 , in addition to the effect of the invention of claim 1, the equipment inside the pressure vessel is uniformly cooled and the amount of internal structural material and damaged core flowing out of the pressure vessel to the containment vessel. Is further suppressed.

According to the third aspect of the present invention, at the time of a virtual accident, the equipment inside the pressure vessel and the damaged core are efficiently cooled, and the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is suppressed. This eliminates the need for special measures to maintain the integrity of the containment vessel, and the amount of internal structural material and damaged core that flows out of the pressure vessel into the containment vessel, as equipment inside the pressure vessel is uniformly cooled. Is further suppressed.

According to the invention of claim 4 , claim 1 or claim 3
In addition to the effect by Motomeko 2, the device is cooled uniformly inside the pressure vessel, the effect of the amount of internal structural materials and damage the core is further suppressed flowing in the containment vessel from the pressure vessel is obtained.

According to the fifth aspect of the present invention, at the time of a virtual accident, the equipment inside the pressure vessel and the damaged core are efficiently cooled, and the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is suppressed. This eliminates the need for special measures to maintain the integrity of the containment vessel, and the inside of the pressure vessel that is efficiently cooled from both inside and outside and flows out of the pressure vessel to the containment vessel. The effect of further reducing the amount of the structural material and the damaged core is obtained.

According to the invention of claim 6, the contract from claim 1 can be obtained.
In addition to the effects of the invention of any one of the preceding claims ,
The equipment inside the pressure vessel is efficiently cooled from both inside and outside, and the amount of the internal structural material and the damaged core flowing out from the pressure vessel to the containment vessel is further suppressed.

[Brief description of the drawings]

FIG. 1 is a system diagram of an emergency core cooling facility of a nuclear reactor as an example of a configuration to which the present invention is applied.

FIG. 2 is an enlarged detailed sectional view of the reactor pressure vessel of FIG.

FIG. 3 is a system diagram of an emergency core cooling system for a nuclear reactor according to a first embodiment of the present invention.

FIG. 4 is a system diagram of an emergency core cooling system of a nuclear reactor as another example of the configuration to which the present invention is applied.

FIG. 5 is a sectional view of an upper part of a pressure vessel of a nuclear reactor according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing the vicinity of an upper shroud of a nuclear reactor according to a third embodiment of the present invention.

FIG. 7 is an enlarged detailed sectional view of a main part of FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Core, 2 ... Pressure vessel, 3 ... Containment vessel, 4 ... Main steam pipe, 5 ... Pedestal part, 6 ... Downcomer, 7 ... Water pool of pressure suppression chamber, 8 ... Jet pump, 10, 11, 1
2, 13, 94 ... piping, 20, 21, 22, 23, 2
4, 28 ... valve, 25, 26, 27 ... check valve, 30 ... water pool, 40, 41 ... pump, 42 ... steam driven pump, 5
0: Intermediate heat exchanger, 51: Filtration and desalination unit, 60: Dryer, 61: Upper shroud, 62: Separator, 63:
Shroud, 64: Lower plenum, 65: Damaged opening, 66
... internal pump, 70 ... main controller, 80, 81,
82: valve operating device, 83: pump operating device, 90: weir, 91
... channel holes, 92, 93 ... structural materials, 95 ... plugs, 96 ... bolts, 97, 98 ... nuts, 99 ... molten metal.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-228191 (JP, A) JP-A-60-222795 (JP, A) JP-A-2-31193 (JP, A) JP-A 61-228 57899 (JP, A) JP-A-60-140190 (JP, A) JP-A-60-53887 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21C 15/18

Claims (6)

(57) [Claims] 1. A pressure vessel containing a reactor core, a containment vessel containing the pressure vessel, a first pipe for supplying a coolant to an upper head of the pressure vessel, and a cooling vessel installed outside the containment vessel. A pool of material, a second pipe connected to supply the coolant in the pool to the first pipe, and a coolant provided in the second pipe to supply the coolant of the pool to the pressure vessel. A first valve and a second valve provided in a first pipe for supplying a coolant to the upper head, and a second valve provided in the second pipe. A third valve provided, the second pipe connected to a first pipe section between the first valve and the second valve, and at least a water level of the pressure vessel falls below a predetermined position. Or the temperature of the pedestal inside the containment vessel is When the flow rate of the emergency core cooling system for injecting water into the pressure vessel is smaller than a predetermined value, the pump provided in the second pipe is started, and the second valve is closed, An emergency core cooling system for a nuclear reactor, comprising: control means for opening the first valve and the third valve. 2. The weir according to claim 1, wherein a weir forming a pool of coolant is formed on a peripheral portion of an upper surface of an upper shroud in the pressure vessel, and the weir is distributed along the weir on the weir. An emergency core cooling system for a nuclear reactor, comprising a plurality of flow holes for flowing out. 3. A pressure vessel containing a core, a containment vessel containing the pressure vessel, a first pipe for supplying a coolant to an upper head of the pressure vessel, and a cooling vessel provided outside the containment vessel. A pool of material, a second pipe connected to supply the coolant in the pool to the first pipe, and a coolant provided in the second pipe to supply the coolant of the pool to the pressure vessel. An emergency core cooling system for a nuclear reactor having a pump that performs a cooling operation that guides a coolant flowing down the side surface of the upper shroud toward the center of the pressure vessel below the upper shroud inside the pressure vessel. An emergency core cooling system for a nuclear reactor. 4. The method of claim 1 or claim 2, below the pressure vessel interior of the upper shroud, that it comprises a structural member for guiding the coolant flowing down the sides of the upper shroud toward the center of the pressure vessel An emergency core cooling system for a nuclear reactor. 5. A pressure vessel containing a core, a containment vessel containing the pressure vessel, a first pipe for supplying a coolant to an upper head of the pressure vessel, and a cooling vessel provided outside the containment vessel. A pool of material, a second pipe connected to supply the coolant in the pool to the first pipe, and a coolant provided in the second pipe to supply the coolant of the pool to the pressure vessel. An emergency core cooling system for a nuclear reactor having a pump that performs a third piping on an upper surface of an upper shroud inside the pressure vessel, the third piping communicating an upper part and a lower part of the upper shroud. An emergency core cooling system for a nuclear reactor, comprising a valve which is plugged with a metal which melts when a temperature exceeds a predetermined value at an opening. 6. The method according to claim 1 or claim 2 or claim 3 or claim 4, the upper surface of the pressure vessel interior of the upper shroud has a third pipe for communicating the top and bottom of the upper shroud An emergency core cooling facility for a nuclear reactor, comprising a valve plugged with a metal that melts when the temperature exceeds a predetermined value at an opening of the third pipe.