JP3150451B2 - Reactor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor power plant, and more particularly to a nuclear reactor plant suitable for ensuring safety in a core melting accident.

[0002]

2. Description of the Related Art Reactor equipment of a nuclear power plant tends to be required to evaluate behavior at the time of a severe accident exceeding a design standard, and at present, there is a tendency that accident countermeasures are actually required. As an example of such an accident, it is assumed that the core in the containment vessel has melted and has flowed out of the pressure vessel.

The following are known techniques for such a virtual accident. 1. High-temperature melting core cooling device (Japanese Unexamined Patent Publication No. 59-19649)
8) In this known technique, a means for holding the core at the time of a core melting accident is installed below the pressure vessel in the containment vessel, and a coolant is supplied below the core to perform cooling from below.

[0004] 2. IAEA-SM-296-I, Symposium, SM-296-I1 (1988)
1 (1988)) Report Chapter 2 In the known technology described in this document, a coolant is guided from an external water source to a containment vessel by a pump or the like and injected into the containment vessel in the event of a core melting accident, and the core flowing out of the containment vessel is cooled from above. There is something like that.

[0005] 3. Nuclear Engineering International (November 1989) (NUCLEA
R ENGINEERING INTERNATIO
NAL (NOVEMBER, 1989)) A known technique described in this document is to make the pressure vessel wet with a core melting accident.

[0006]

However, the above-mentioned known technology has the following problems. In the prior art 1, since the temperature of the storage container increases due to radiation, a means for lowering the temperature of the storage container is separately required.

In the prior art 2, since the pressure of the containment vessel increases due to the generation of the gas phase accompanying the erosion of the concrete, a means for lowering the pressure of the containment vessel is separately required.

In the prior art 3, when the core comes into contact with the coolant, water evaporates rapidly, causing a so-called steam explosion, which may cause a dynamic load. Therefore, the pressure resistance of the containment vessel is increased. There is a need.

On the other hand, as an example of an accident within a normal design standard range, there is an accident of loss of coolant due to breakage of a main steam pipe or the like. In this case, a coolant is usually injected into the pressure vessel from a dynamic means such as a pump or a static means such as a water pool to maintain the core inundation. At this time, if the water level in the pressure vessel further rises, the coolant may flow out of the break into the lower dry well, and the equipment installed in the lower dry well may become unusable due to watering.

A first object of the present invention is to provide an atomic reactor capable of preventing the generation of a dynamic load and rapidly cooling without requiring additional equipment for lowering the temperature and pressure of the containment vessel in the event of a reactor core melting accident. Furnace equipment.

A second object of the present invention is to provide a nuclear reactor facility capable of improving the soundness of equipment installed in a lower drywell in the event of a coolant loss accident.

[0012]

In order to achieve the first object, the present invention provides a pressure vessel having a core therein, a storage vessel in which the pressure vessel is disposed, and supplying a coolant to the pressure vessel. A nuclear reactor having a pressure suppression chamber provided with a water pool to be cooled, a support means for holding the core in a lower drywell below the pressure vessel when an accident occurs in which the core melts, and cooling the water pool. A first cooling means for supplying a material to a space below the support means; and a second cooling means for supplying a coolant of the water pool to a space above the support means.

Preferably, the first cooling means has a first pipe connecting the water pool and a space below the support means, and a first valve provided in the first pipe.
The second cooling means has a second pipe connecting the water pool and a space above the support means, and a second valve provided in the second pipe.

[0014]

[0015]

Preferably, the supporting means has an upper surface in contact with the core made of a material having a high melting point and a low thermal conductivity, and a lower surface made of a material having a high thermal conductivity and a high ductility.

More preferably, the first cooling means has a first pipe connecting the water pool and a space below the support means, and a first valve provided in the first pipe. The second cooling means includes a third pipe connecting a space below the support means and a space above the support means, and a spray nozzle provided in the third pipe.

[0018]

[0019]

Preferably, the first cooling means is a second cooling means for connecting the water pool to a space below the supporting means.
And a second cooling means for connecting a space below the support means and a space above the support means.
And a third valve provided in the third pipe and the third pipe.

[0021]

[0022]

[0023]

[0024]

[0025]

Preferably, in the nuclear reactor equipment, a drainage space for guiding a coolant in the lower drywell, a fifth pipe connecting the drainage space to the support means, and a fifth pipe are provided. And a first control means for opening the fourth valve when the water level of the pressure vessel falls below a predetermined value.

[0027] More preferably, in the nuclear reactor equipment, pressure reducing means for reducing the pressure of the containment vessel,
A sixth pipe connecting the pressure reducing means and the pressure suppression chamber and a fifth valve provided in the sixth pipe, and the fifth valve is opened when the pressure of the containment vessel exceeds a predetermined value. And second control means.

Preferably, in the above-mentioned nuclear reactor facility, the support means has a bottom portion whose peripheral portion is higher than a central portion.

More preferably, in the above-mentioned nuclear reactor equipment, the support means has fins on its lower surface for promoting heat radiation.

Preferably, in the above-mentioned nuclear reactor facility, the support means has a plurality of pipes for guiding a coolant below.

In order to achieve the second object, the present invention comprises a pressure vessel having a core therein, a storage vessel in which the pressure vessel is arranged, and a water pool for supplying a coolant to the pressure vessel. In a nuclear reactor having a pressure suppression chamber, and a vent pipe connecting the pressure suppression chamber and a dry well in the containment vessel, a lower dry well below the pressure vessel and another dry well may be formed in the vent pipe. Are connected only by a seventh pipe having an upper end at a position higher than the upper end.

In order to achieve the above first and second objects, the present invention provides a pressure vessel having a core therein, a storage vessel in which the pressure vessel is arranged, and a water pool for supplying a coolant to the pressure vessel. And a vent pipe connecting the pressure suppression chamber and the drywell in the containment vessel, wherein, when an accident in which the core melts occurs, a lower portion below the pressure vessel Support means for holding the core in a drywell, first cooling means for supplying coolant of the water pool to a space below the support means, and coolant for cooling the water pool in a space above the support means And a lower drywell below the pressure vessel and another drywell are connected only by a pipe having an upper end at a position higher than an upper end of the vent pipe. .

[0033]

In the present invention constructed as described above, the core is cooled indirectly from below by the first cooling means supplying a coolant to the space below the support means, and the second core is cooled by the second cooling means.
Is cooled directly from above by supplying coolant to the space above the support means.

The first cooling means has a first pipe and a first valve, and the second cooling means has a second pipe and a second valve. By performing cooling, cooling is quickly performed . Et al of the support means is not melt than that top surface is a high melting point, the temperature of the coolant from it without melting does not heat the lower surface than it is low thermal conductivity, and lower surface is high thermal conductivity Even if the difference is small, the amount of heat transfer is large, and it is hard to break due to its high ductility. Further, the second cooling means connects the space below the support means and the space above the support means with a third pipe and a spray nozzle, thereby simplifying the valve and the pipe . Also,
Said first cooling means fourth piping connecting the space below the supporting means and the water pool directly, the second cooling means said third pipe and said support means in a third valve By connecting the space below the space and the space above the support means, the piping is simplified . Also, the first control means by directing coolant to the fourth fifth open valve drainage space through piping, to completely remove the coolant in the lower drywell. Further, the lower surface of the supporting means is higher at the peripheral portion than at the central portion, so that steam is easily released by buoyancy, thereby promoting convective heat transfer. Further, convection heat transfer is promoted by providing a large number of pipes for guiding fins and coolant on the lower surface of the support means.

In the present invention, the lower drywell and the other drywell are the only pipes connected to each other.
Since the upper end of the pipe 7 is higher than the upper end of the vent pipe, the coolant flows into the vent pipe instead of the seventh pipe and does not flow into the lower drywell in the event of a coolant loss accident.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. A first embodiment of the present invention will be described with reference to FIGS. First, the overall configuration of the boiling water reactor equipment of the present embodiment will be described with reference to FIG. In FIG. 1, a reactor core 1 is surrounded by a pressure vessel 2, and the pressure vessel 2 is contained inside a containment vessel 3. Coolant is supplied into the pressure vessel 2 by a main steam pipe 12. The pressure suppression chamber 4 provided around the pressure vessel 2 is connected to a dry well 10 inside the containment vessel 3 by a vent pipe 5. Water pools 6 and 7 for supplying a coolant to the pressure vessel 2 by gravity are installed above the pressure suppression chamber 4 inside the containment vessel 3.
A water pool 8 for cooling the storage container 3 and an air flow path 9 are provided outside the storage container 3.

A core catcher 20 is provided in the lower dry well 11 located below the pressure vessel 2. Water pool 8 in the suppression chamber 4 above the core catcher 20
And the space 11A below the core catcher 20 are connected by a pipe 30 and a valve 40, and the space 11A and the lower drywell 11 are connected by a pipe 31. Further, the space 11B above the core catcher 20 is suppressed in pressure. The water pool 8 of the chamber 4 is connected with the pipe 32 and the valve 41. The lower dry well 11 and the upper dry well 10 are connected by a pipe 33, and the upper end thereof is higher than the upper end of the vent pipe 5 of the dry well 10. Valves 40 and 4
1 is provided with a living body shielding plate 72 in consideration of manual operation when a failure occurs.

The temperature of the lower drywell 11 is measured by a thermometer 50, and the value is sent to a main controller 60. The main controller 60 sends signals for opening and closing the valves 40 and 41 according to the temperature of the lower drywell 11 to the valve operators 70 and 71.
Send to The main controller 60 and the valve controllers 70 and 71 are provided with an emergency battery (not shown) used when the in-house power supply cannot be used.

The diameter of the pipe 33 should be sufficiently large, for example, 40 cm, in order to suppress a rise in the pressure of the lower dry well 11 when the pipe arranged on the surface of the pressure vessel 2 in contact with the lower dry well is broken. Is desirable. The pipes 30 and 32 have a diameter, for example, 0.1 m, at which a flow rate of cooling water sufficient to cool the core 1 is obtained.

FIG. 2 is a sectional view of the core catcher 20. The upper surface of the core catcher 20 is made of a material 21 having a high melting point and a low thermal conductivity such as magnesium oxide, and the lower surface is made of a material 22 having a high thermal conductivity and a high ductility such as carbon steel. .

For example, if the thickness of the material 21 made of magnesium oxide is 3 cm and the thickness of the material 22 made of carbon steel is 1 cm, almost all the heat generated in the core 1 is removed only by the core catcher 20. 4 × 10 5 W / m 2 required for the heat treatment. Since the heat flux from the upper part of the core 1 can be expected to be the same or more, the core catcher 20 can further increase the thickness of the material 21 and the material 22.

In the reactor facility having the above-described structure, in the event of a coolant loss accident such as breakage of a pipe connected to the pressure vessel 2, for example, the main steam pipe 12, the pressure vessel 2 The pressure inside the dry well 10 increases and the pressure inside the dry well 10 increases. Pressure vessel 2 and dry well 1
When the pressure difference of 0 becomes sufficiently small, the water pool 6
The coolant in the water pool 7 flows into the pressure vessel 2, and the water level inside the pressure vessel 2 is maintained above the core 1. At this time, since the water pool 6 and the water pool 7 hold a sufficient amount of coolant for hydrating the pressure vessel 2, when the water level inside the pressure vessel 2 further rises, the coolant becomes main. It flows out from the break of the steam pipe 12 to the dry well 10. The coolant flowing out to the dry well 10 accumulates in the dry well 10, and flows into the pressure suppression chamber 4 through the vent pipe 5 when the water level reaches the upper end of the vent pipe 5.

If the core 1 fails to be cooled at the time of the above-described coolant loss accident and the core melting accident occurs, the core 1 flows out of the pressure vessel 2 to the lower dry well 11 and the core 1 It is held by the catcher 20. The temperature of the lower dry well 11 rises due to radiation from the core 1 and convective heat transfer. When the temperature measured by the thermometer 50 exceeds a predetermined value, for example, 300 ° C., the main controller 60 sends a signal to open the valve 40 to the valve operating device 70. When the valve 40 is opened, the water in the pressure suppression chamber 4 is discharged by gravity into the pipe 30.
Flows through the space 11A below the core catcher 20 to indirectly cool the core 1 from below by heat conduction through the structural material of the core catcher 20. Core 1
The steam generated by the heat from the gas flows out to the lower dry well 11 through the pipe 31. After a certain time delay, for example 200 seconds, after the valve 40 is opened, the main controller 60 sends a signal to open the valve 41 to the valve actuator 71. When the valve 41 is opened, water in the pressure suppression chamber 4 flows into the space 11B above the core catcher 20 through the pipe 32 by gravity, and cools the core 1 from above. FIG. 3 shows the time change of the ambient temperature of the lower dry well 11 at this time, and FIG. 4 shows the time change of the temperature at the representative point of the core 1 (at a position 1 cm from the upper surface of the core 1).

In FIG. 3, in the conventional example in which the reactor core 1 is cooled only from the lower part, the ambient temperature rises with the passage of time due to radiation and convective heat transfer, and finally the storage portion of the control cable installed in the storage container 3. The coating of the electrical penetration melts and a gas phase leak occurs. However, in this embodiment, when the valve 41 is opened after the cooling from the lower portion and the upper water injection is started, the ambient temperature is almost maintained at a temperature T1 lower than the leak occurrence temperature.

In FIG. 4, similarly, in the conventional example, the core 1
After the solidification by the lower cooling, the representative point temperature does not drop much from the temperature T2 at the solidification point. In this embodiment, however, water injection from the upper part is started after the core 1 is solidified by the lower cooling, and the representative temperature with time elapses. Temperature is freezing point temperature T
Decreases further from 2 and cools quickly.

As described above, the temperature of the lower dry well 11 is lowered by the lower cooling and the subsequent cooling by the upper water injection,
When the temperature falls below a predetermined value, for example, 200 ° C., the main controller 60
Sends a signal to close the valves 40 and 41 to the valve operating device 70 and the valve operating device 71 to stop cooling. If the temperature rises again due to heat generation from the core 1 after a lapse of time after the stop, the valves 40 and 41 are opened again by the main controller 60 to perform cooling. The valves 40 and 41 controlled by the main controller 60
, The temperature of the lower dry well 11 is maintained below a certain level, and the water level of the pressure suppression chamber 4 is maintained at a high position.

On the other hand, at this time, the steam generated by the decay heat of the reactor core 1 flows into the pressure suppression chamber 4 through the pipe 33, the dry well 10, and the vent pipe 5, and is condensed. With the condensation of the steam, the temperature of the pressure suppression chamber 4 rises, heat is released to the outside of the containment vessel 3 due to the temperature difference with the water pool 8, and the outside of the containment vessel 3 is also released by natural convection in the air flow path 9. Heat is released. Therefore, the pressure of the storage container 3 is maintained at or below the design value.

According to the present embodiment configured as described above,
Since the coolant flows into the pressure suppression chamber 4 through the vent pipe 5 at the time of the coolant loss accident, the coolant does not flow into the lower dry well 11 and the equipment installed in the lower dry well 11 becomes wet. Never. Therefore, the soundness of these devices is enhanced. At the time of core melting accident,
As described above, since the probability of the lower dry well 11 being wetted in the coolant loss accident is reduced, the lower dry well 11 hardly contains the coolant. Therefore, when the core 1 is melted, flows out of the pressure vessel 2 and comes into contact with the coolant, the generation of a dynamic load caused by rapid evaporation of water is reduced. Material 2 on the upper surface of the core catcher 20
Since 1 has a high melting point, it does not melt even when in contact with the reactor core 1 and has a low thermal conductivity, so that the temperature of the lower surface decreases and the material 22 of the lower surface does not melt. Furthermore, since the material 22 on the lower surface has a high thermal conductivity, even if the temperature difference with the coolant is small, the amount of heat transfer is large, and the material is hardly damaged due to its high ductility. Further, since the core 1 is cooled by injecting water not only from the lower part but also from the upper part, when the upper part water injection is started, the ambient temperature is lowered more quickly than in the conventional example, and the core 1 is cooled quickly. Therefore, there is no danger of gas-phase leakage, that is, leakage from the electric penetration, which is a storage portion of the control cable installed in the containment vessel 3, and the temperatures of the lower dry well 11 and the dry well 10, which were conventionally required to prevent leakage. No additional equipment for lowering the power consumption is required. Further, since the core 1 is held by the core catcher and heat is removed from below, no gas phase is generated due to the erosion of the lower part of the containment vessel 3, and the pressure rise in the containment vessel 3 is reduced. Therefore, additional equipment for lowering the pressure of the storage container 3 becomes unnecessary. When water is injected from above the core 1, the core 1 is already solidified, so that the amount of steam generated when the coolant contacts the core 1 is limited. Therefore, generation of a dynamic load caused by rapid generation of steam is reduced. Further, since the valves 40 and 41 perform opening and closing operations under the control of the controller 60, the temperature of the lower dry well 11 can be maintained at a certain level or less, and the water level of the pressure suppression chamber 4 can be maintained at a high position.

A second embodiment of the present invention will be described with reference to FIG. FIG. 5 is an overall configuration diagram of the boiling water reactor equipment of the present embodiment. Parts common to those of the nuclear reactor equipment of the first embodiment shown in FIG. 1 are indicated by common numbers. In FIG.
The difference from the reactor equipment of Fig. 1 is that the core catcher 2
This is a point in which a space 511A below 0 and a space 11B above the core catcher 20 are connected by a pipe 34, and a spray nozzle 35 is installed at the end thereof. Other points are shown in Fig. 1.
It is almost the same as the nuclear reactor equipment.

The operation of the reactor equipment having the above-described structure at the time of the coolant loss accident is the same as that of the reactor equipment shown in FIG. The operation at the time of the core melting accident is almost the same as that of the reactor equipment of FIG. 1 until the lower part is cooled. That is, the core 1 is held by the core catcher 20, and the main controller 560 opens the valve 40 as the temperature of the dry well 11 increases. Suppression chamber 4
Of water flows into the space 511A below the core catcher 20 through the pipe 30, and cools the core 1 from below the core catcher 20. The coolant flowing into the lower portion of the core catcher 20 partially evaporates, but the water level gradually rises, and finally, the coolant passes through the pipe 34 and the spray nozzle 35 to form water droplets and falls down the lower dry well 11. The core 1 is cooled from above. At this time, the steam generated by the heat of the core 1 flows out to the lower drywell 11 through the pipes 31 and 34, but the flow rate flowing below the core catcher 20 through the pipe 30 is generated in the core 1. The diameter of the pipe 30 is set to, for example, 0.15 m so as to increase the water level more than necessary to remove the heat.

By cooling from the upper and lower parts of the core catcher 20 as described above, the temperature of the lower dry well 11 immediately decreases, and when the temperature of the lower dry well 11 falls below a predetermined value, for example, 200 ° C. 560
Sends a signal to close the valve 40 to the valve actuator 70 to stop cooling. The heat removal path at this time is the same as in FIG.

According to this embodiment, the core catcher 20
Since cooling from above is performed by water droplets of the coolant using the pipe 34 and the spray nozzle 35, the same effect can be obtained even if the number of pipes and valves is reduced as compared with the first embodiment.

A third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is an overall configuration diagram of the boiling water reactor equipment of the present embodiment. Parts common to those in the nuclear reactor of FIG. 5 are indicated by common numbers. 6, the difference from the second embodiment shown in FIG. 5 is that the water pool 8 of the
A pipe 630 connecting the space 611A below the catcher 620 is directly connected without using a valve.
A and the pressure suppression chamber 4 are connected by a pipe 36 to form a circulation loop, and the space 611A and the core catcher 6
The point where the space 11B above the space 20 is connected with the pipe 634, the valve 42, and the valve 43, and the core catcher 62
0 structure. Other points are the same as those of the nuclear reactor equipment of FIG.

FIG. 7 is a sectional view of the core catcher 620.
Shown in In this embodiment, the core catcher 620 is used.
Since the lower part of the plate is in constant contact with the coolant, a thin plate 623 made of a material suitable for preventing corrosion, for example, a stainless steel plate, is attached below the material 622. Also, the material 621
A thin plate 624 of a material suitable for facilitating maintenance during normal operation, for example, a stainless steel plate 624 is attached to the upper part of the upper part.

FIG. 8 is a sectional view of the valves 42 and 43. The valve 43 has a structure in which a stopper 44 is made of a metal that melts when the temperature exceeds a predetermined value, for example, lead having a melting temperature of 328 ° C. Note that the valve 42 is a valve that closes to prevent the coolant from flowing out when the valve 43 is replaced for maintenance or the like, and is normally open.

In the reactor having the above-described structure, the operation at the time of the coolant loss accident is the same as that of the reactor shown in FIG. At the time of the core melting accident, the core 1 flowing into the lower drywell 11 is held by the core catcher 620, but the coolant already exists in the space 611A below the core catcher 620, and the core 1 Is cooled indirectly from below. Steam generated by heat from the reactor core 1 flows into the water pool of the pressure suppression chamber 4 through the pipe 36 by natural circulation and condenses.

On the other hand, when the temperature of the lower drywell 11 rises due to radiation from the reactor core 1 and convection heat transfer and exceeds a predetermined value, for example, 328 ° C., the metal constituting the plug 44 of the valve 43, for example, lead, becomes It melts and falls, and the valve 43 is opened. When the valve 43 is opened, the core catcher 62
The coolant that has risen in water level from below 0 is piping 634,
It flows into the lower drywell 11 through the valve 42 and the valve 43 and cools the core 1 from the upper part.

The heat removal path of the steam generated in the upper space 11B of the lower dry well 11 by the decay heat of the core 1 is the same as that in FIG.

According to the present embodiment, similarly to the first and second embodiments, the effect of increasing the soundness of the equipment in the lower drywell 11 at the time of the coolant loss accident is obtained. Also, in the event of a core melting accident, the first
In addition, the same effect at the time of cooling as in the second embodiment, that is, the effect of preventing generation of a dynamic load, prevention of breakage of the core / catcher, and elimination of additional equipment for temperature / pressure drop can be obtained.

A fourth embodiment of the present invention will be described with reference to FIGS. This embodiment uses an on-off valve 943 that operates in conjunction with the temperature, instead of the valves 42 and 43 in the third embodiment of FIG. 9 and 10
FIG. 9 is a diagram showing the configuration and operation of the on-off valve 943 of the present embodiment. In FIG. 9, an on-off valve 943 is provided integrally with a member 945 in which a metal 46 having a low linear expansion coefficient such as tungsten and a metal 45 having a high linear expansion coefficient such as zinc are adhered to the member 945. Moving partition 4
7 and the packing 48 for preventing the coolant from flowing out.
Is provided.

In the above configuration, the on-off valve 943 is closed by the partition plate 47 at a normal temperature. FIG. 9 shows this state. When the temperature of the space in which the on-off valve 943 is installed rises during the core melting accident, since the metal 45 expands more than the metal 46, the partition plate 47 moves downward to open the on-off valve 943, and the coolant Flows out through the pipe 934 into the space where the opening valve 943 is installed. FIG. 10 shows this state.

Thereafter, a certain amount of coolant flows out and the on-off valve 94
When the temperature of the space in which 3 is installed decreases, metal 45
And 46 are compressed, the partition plate 47 moves upward again, the on-off valve 943 is closed, and the state returns to the state shown in FIG.

According to the present embodiment, it is possible to adjust the flow of the coolant without separately providing a control device, and to obtain the same effects as those of the first and second embodiments.

A fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, a float valve 1142 is used instead of the valve 42 in FIG. 8, and FIG.
FIG. 14 is a configuration diagram showing a state in which 42 is arranged on a core catcher 620. Parts common to those in FIG. 8 are indicated by common numbers.

In FIG. 11, a float valve 1142 is
The pipe 1134 is provided with a float 80, a container 81 containing the float 80 and having a flow path hole above and below, and a partition plate 1147 that moves in conjunction with the float 80. A heat shield plate 82 having a large number of flow paths 83 is provided on the side of the float valve 1142, so that a rapid rise in temperature due to radiation or the like is suppressed and deformation and breakage are prevented.

In the above configuration, when the core meltdown accident occurs, the valve 4
When the temperature of the space 1111D where the 3 is installed rises, first, the plug 44 melts, the valve 43 is opened, the coolant flows out, and the temperature of the space 1111D decreases.

A part of the coolant flowing into the space 1111D flows into the space 1111C in which the float valve 1142 is installed through the flow path 83, and when the water level reaches the float 80, the float 80 rises by buoyancy and the partition plate 1147 is raised.
Rises, the float valve 1142 is closed, the flow of the coolant stops, and the cooling ends. When the temperature of the space 1111D in which the valve 43 is installed rises again and the coolant evaporates and the water level falls, the float 80 descends and the float valve 1
142 is opened to start cooling again.

According to this embodiment, the same effect as that of the fourth embodiment can be obtained.

A sixth embodiment of the present invention will be described with reference to FIG. FIG. 12 is an overall configuration diagram of the boiling water reactor equipment of the present embodiment. In the present embodiment, the present invention is applied to a boiling water reactor in which steam generated by decay heat of the reactor core 1 is condensed in the condenser 14 of the water pool 15. Parts common to those in FIG. 6 are indicated by common numbers. In FIG.
The main difference from the third embodiment of FIG. 6 except that the reactor is of the above-mentioned type is that a space 13 for guiding coolant from the lower part of the core catcher 1220 is provided.
The point is that the space 1211B above the catcher 1220 is connected by the pipe 91 and the valve 90.

In the reactor facility having the above-described structure, in the event of a loss of coolant, since the dry well 1210 and the lower dry well 1211 are connected only by the pipe 1233, the operation at this time is as shown in FIG. Is the same as In other words, the lower dry well 11
Is less likely to have coolant. However, in the reactor equipment of the present embodiment, if the coolant is
Even if it flows into 211, when the water level in the furnace inside the pressure vessel 1202 reaches a set value, for example, the upper end position of the core 1, the main controller 61 sends a signal to open the valve 90 to the valve actuator 73, and the coolant is Since the coolant flows into the space 13 through the pipe 91, the coolant does not completely exist in the lower dry well 1211.

The operation at the time of the core melting accident is almost the same as that of the nuclear reactor equipment of the embodiment of FIG. 6, and the core 1 flowing out to the lower dry well 1211 is already
Cooling is indirectly performed by the coolant existing in the space 1211A below the 220, and thereafter, at a predetermined temperature, the valve 43 is opened, and the coolant cools the core catcher 1220 from above.

In addition to the above operation, in the configuration of the present embodiment, a part of the steam is supplied to the dry well 1210 and the pipe 1.
237 into the condenser 14 and transfer heat to the water pool 15
And condensed, and the condensed water returns to the pressure vessel 1202 by gravity or returns to the pressure suppression chamber 1204 through the pipe 1239.

According to the present embodiment configured as described above,
In addition to obtaining the same effects as the third embodiment, since the pipe 91 and the valve 90 have a function of guiding the coolant to the space 13, the coolant is completely removed from the lower dry well 1211 in the event of a coolant loss accident. it can. The core 1 and containment vessel 1
Since there is no generation of non-condensable gas caused by the contact and reaction of 203, it is possible to prevent the performance of the condenser 14 from deteriorating due to non-condensable gas.

This embodiment is an example in which the present invention is applied to a boiling water reactor in which the pipe 91, the valve 90, and the space 13 are condensed by a condenser, and is limited to this type of reactor. However, it is applicable to other types of boiling water reactors.

A seventh embodiment of the present invention will be described with reference to FIG. FIG. 13 is an overall configuration diagram of the boiling water reactor equipment of the present embodiment. In the present embodiment, the present invention is applied to a reactor of a type having no water pool above the suppression chamber and having a different water pool outside the pressure vessel. Parts common to those in FIG. 6 are indicated by common numbers.

In FIG. 13, the main difference from the third embodiment of FIG. 6 except that the reactor is of the above-described type is that the conventional means for lowering the pressure in the containment vessel 1303 is a conventional residual reactor. In addition to the heat removal system (not shown),
3 is provided with a filter vent device 94 that operates when the pressure reaches a set value, for example, 85% of the design pressure, a pipe 93 and a valve 92 communicating therewith, and a valve controller 74 for controlling the valve 92; Main controller 62 for transmitting control signals
Is provided.

The operation of the nuclear reactor with the above-described configuration at the time of the core melting accident is almost the same as that of the nuclear reactor of FIG. 6 shown in FIG. Is cooled indirectly by the coolant existing in the space 1311A below the valve, and then the valve 1343 is opened at a predetermined temperature, and the coolant cools the core catcher 1320 from above. The pipe 1334 includes a space 1311A below the core catcher 1320 and a pipe 1 from the top of the suppression chamber 1304.
336 is also connected so that excess cooling water is supplied to the suppression chamber 1304.
Return to pool 1308 in

At the time of this cooling operation, in a normal boiling water reactor, a residual heat removal system (not shown) operates to lower the temperature of the pressure suppression chamber 1304.
However, if the residual heat removal system does not operate due to any failure, the pressure inside the storage container 1303 gradually increases. In the present embodiment, the value of the internal pressure of the containment vessel 1303 measured by the pressure gauge 51 is sent to the main controller 62, and this value reaches a set value, for example, 85% of the design pressure of the containment vessel 1303. Then, the main controller 62 sends a signal to open the valve 92 to the valve controller 74. By this signal, the vapor existing in the upper space of the pressure suppression chamber 1304 flows into the filter vent device 94 through the pipe 93 and the valve 92, and the pressure of the containment vessel 1303 is maintained at or below the design pressure.

According to the present embodiment, in the event of a core melting accident, the same cooling effect as that of the first and second embodiments, that is, the prevention of generation of a dynamic load and the core catcher can be achieved without providing a separate control device. In addition to the effect of preventing the damage of the storage container and the need for additional equipment for lowering the temperature, the pressure of the storage container can be maintained at or below the design value only by adding a simple device without significantly changing the design of the storage container.

An eighth embodiment of the present invention will be described with reference to FIG. This embodiment is another embodiment relating to the core catcher in the first to seventh embodiments described above. FIG. 14 shows the core catcher 1420 of this embodiment.
FIG. In FIG. 14, the core catcher 1420 of this embodiment is configured such that the bottom of the core catcher 20 in the embodiment of FIG. 1 is higher at the periphery than at the center, and heat is radiated to the lower surface of the core catcher 1420. Fins 95 are provided for promoting.

In the above configuration, the lower surface of the core catcher 1420 has a large heat transfer area because the fins 95 are provided, and the amount of heat transfer from the lower surface of the core catcher 20 to the coolant is large. Also, the bottom of the core catcher 1420 is higher at the periphery than at the center,
The vapor generated by evaporating the coolant by the heat from the reactor core 1 on the lower surface of the core catcher 1420 is easily released due to buoyancy, and the amount of heat transfer to the coolant increases.

According to the present embodiment, in addition to the effect of the core catcher 20 of the first embodiment having the effect of preventing melting and breakage, the amount of heat transferred from the reactor core 1 increases, so that cooling can be performed more quickly.

A ninth embodiment of the present invention will be described with reference to FIG. This embodiment is another embodiment relating to the core catcher, similarly to the eighth embodiment. FIG. 15 is a sectional view of the core catcher 1520 of the present embodiment. FIG.
In the core catcher 1520 of the present embodiment,
The bottom of the core catcher 20 in the embodiment of FIG. 1 is configured so that the periphery is higher than the center, and
A large number of pipes 96 for guiding the coolant are provided in the space below the catcher 20, and the pipes 96 are connected to the pipes 30 connected to the water pool 8 of the pressure suppression chamber 4.

According to the present embodiment, in addition to the effect of increasing the amount of heat transfer due to the fact that the peripheral portion of the core is higher than the central portion, the heat transfer area to the coolant is increased by the large number of pipes 96, and the core catcher 20 Since heat is quickly transmitted from the lower surface to the coolant, the core is cooled more quickly.

In the first to ninth embodiments, the case where the present invention is applied to a boiling water reactor has been described as an example.
The application of the present invention is not limited to the boiling water type, but may be applied to other types, that is, a pressurized water reactor or the like as long as it has a pressure suppression chamber having a water pool.

[0086]

According to the present invention, the core can be cooled not only from below but also from above, so that cooling can be performed effectively. In addition, since cooling is performed quickly to lower the temperature and there is no danger of leakage from electric penetration, no additional equipment for lowering the temperature is required. Further, since the cooling from below is indirect cooling, no gas phase is generated due to erosion of the containment vessel, and no additional equipment for reducing the pressure is required . Since the upper surface of or support means is a high-melting-low thermal conductivity material without melting top, bottom surface, the lower surface is not easily damaged so high ductility greater amount of heat transfer so high thermal conductivity. Further, since the valve is controlled to perform the opening / closing operation, the water level of the pressure suppression chamber can be maintained at a high position while the temperature of the lower dry well is maintained at a certain level or less. Further, since the space below the support means and the space above the support means are connected by using the spray nozzle, the valve and the piping can be simplified . Because the or the water pool and the support means below the space is directly linked also connects the space and the space above the support means downwardly simplifies the piping. Since complete removal of the coolant in the lower dry wells et al led coolant into the drainage space is, it is possible to reduce the occurrence of dynamic loads with steam generated by the contact of the core with the coolant. Further, since no non-condensable gas is generated, it is possible to prevent the performance of the condenser from deteriorating. By simply adding a simpler device, the pressure of the containment vessel can be maintained at or below the design value. Further, since the steam is easily released by the buoyancy in the support means, convective heat transfer can be promoted and cooling can be performed quickly. Further, since a large number of pipes for guiding the coolant are provided in the support means, convective heat transfer can be promoted and cooling can be performed quickly. Further, according to the present invention, since the coolant does not flow into the lower drywell in the event of the loss of the coolant, the soundness of the equipment in the lower drywell is improved. Therefore, even in the event of a core melting accident, it is possible to reduce the generation of dynamic loads due to steam generated by contact with the core.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a boiling water reactor facility according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a core catcher.

FIG. 3 is a diagram showing a change over time of an ambient temperature of a lower dry well.

FIG. 4 is a diagram showing a temporal change in temperature at a representative point of a core.

FIG. 5 is an overall configuration diagram of a boiling water reactor facility of a second embodiment.

FIG. 6 is an overall configuration diagram of a boiling water reactor facility of a third embodiment.

FIG. 7 is a sectional view of a core catcher.

FIG. 8 is a sectional view of a valve.

FIG. 9 is a diagram illustrating the configuration and operation of an on-off valve according to a fourth embodiment.

FIG. 10 is a diagram showing the configuration and operation of an on-off valve.

FIG. 11 is a configuration diagram showing an arrangement state of a float valve and a core catcher according to a fifth embodiment.

FIG. 12 is an overall configuration diagram of a boiling water reactor facility of a sixth embodiment.

FIG. 13 is an overall configuration diagram of a boiling water reactor facility of a seventh embodiment.

FIG. 14 is a sectional view of a core catcher according to an eighth embodiment.

FIG. 15 is a sectional view of a core catcher according to a ninth embodiment.

[Explanation of symbols]

 Reference Signs List 1 core 2 pressure vessel 3 containment vessel 4 pressure suppression chamber 5 vent pipe 8 water pool 10 dry well 11 lower dry well 11A lower space 11B upper space 13 space 20 core / catcher 21 material 22 material 30 pipe 31 pipe 32 pipe 33 pipe 34 Piping 35 Spray nozzle 36 Piping 40 Valve 41 Valve 43 Valve 44 Plug 45, 46 Metal 47 Partition plate 60 Main controller 61 Main controller 62 Main controller 80 Float 90 Valve 91 Piping 92 Valve 93 Piping 94 Filter venting device 95 Fin 96 Piping 511A Lower space 560 Main controller 611A Lower space 620 Core catcher 621 Material 622 Material 623 Thin plate 630 Piping 634 Piping 934 Piping 943 Valve 945 Member 1134 Piping 1142 Valve 1147 Partition plate 1202 Force vessel 1203 Containment vessel 1204 Suppression chamber 1205 Vent pipe 1210 Dry well 1211 Lower dry well 1211A Lower space 1211B Upper space 1220 Core catcher 1230 Pipe 1233 Pipe 1236 Pipe 1302 Pressure vessel 1303 Storage vessel 1304 Pressure suppression chamber 1305 Dry pipe Well 1311 Lower dry well 1311A Lower space 1311B Upper space 1320 Core catcher 1330 Piping 1334 Piping 1336 Piping 1342 Valve 1343 Plug 1420 Core catcher 1520 Core catcher

Continuation of the front page (56) References JP-A-61-193095 (JP, A) JP-A-58-100782 (JP, A) JP-A-3-115898 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) G21C 9/016

Claims (11)

(57) [Claims] 1. A reactor facility comprising a pressure vessel containing a reactor core, a containment vessel in which the pressure vessel is disposed, and a pressure suppression chamber having a water pool for supplying a coolant to the pressure vessel, wherein the reactor core comprises: A supporting means for holding the core in a lower dry well below the pressure vessel in the event of an accident that melting occurs, a first cooling means for supplying a coolant of the water pool to a space below the supporting means, A second cooling means for supplying a coolant of the water pool to a space above the support means. 2. The nuclear reactor facility according to claim 1, wherein said first cooling means is provided in a first pipe and said first pipe connecting said water pool and a space below said supporting means. A second valve connecting to the water pool and the space above the support means, and a second valve provided in the second pipe. Reactor equipment characterized by having. 3. The reactor facility according to claim 1, wherein said support means has an upper surface made of a material having a high melting point and a low thermal conductivity and a lower surface made of a material having a high thermal conductivity and a high ductility. Reactor equipment characterized by being carried out. 4. The nuclear reactor facility according to claim 1, wherein said first cooling means is provided in a first pipe and said first pipe connecting said water pool and a space below said supporting means. A third valve connecting the space below the support means and the space above the support means, and a spray provided in the third pipe. A nuclear reactor having a nozzle. 5. The reactor facility according to claim 1, wherein said first cooling means has a fourth pipe connecting said water pool and a space below said support means, and said second cooling means. Reactor equipment, characterized in that the means has a third pipe connecting a space below the support means and a space above the support means, and a third valve provided in the third pipe. 6. The reactor facility according to claim 1, wherein a drainage space for guiding a coolant in the lower drywell, a fifth pipe connecting the drainage space and the support means, and the fifth pipe are provided. A first valve for opening the fourth valve when the water level of the pressure vessel falls below a predetermined value.
Nuclear reactor equipment comprising: 7. The reactor facility according to claim 1, wherein a pressure reducing means for reducing the pressure of the containment vessel, a sixth pipe connecting the pressure reducing means and the pressure suppression chamber, and the sixth pipe. And a second control means for opening the fifth valve when the pressure of the containment vessel exceeds a predetermined value. 8. A nuclear reactor facility according to claim 1, wherein said support means has a bottom portion whose peripheral portion is higher than a central portion. 9. The nuclear reactor facility according to claim 1, wherein said support means has fins on its lower surface for promoting heat radiation. 10. The reactor facility according to claim 1, wherein said support means has a plurality of pipes for guiding a coolant below. 11. A pressure vessel having a core therein, a containment vessel in which the pressure vessel is arranged, a pressure suppression chamber having a water pool for supplying a coolant to the pressure vessel, the pressure suppression chamber, and the containment vessel. A reactor that has a vent tube connecting the dry well in the reactor, wherein, when an accident occurs in which the core melts, a support means for holding the core in a lower dry well below the pressure vessel; and A first cooling means for supplying a coolant to a space below the support means, and a second cooling means for supplying a coolant for the water pool to a space above the support means; and A reactor facility, wherein a lower drywell below a pressure vessel and another drywell are connected only by a pipe having an upper end higher than an upper end of the vent pipe.