JPH09119995A - Reactor plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool a reactor pressure container when an emergency reactor cooling system does not operate when a cooling material is lost by accident. SOLUTION: A spray pipe 15 is provided in a skirt 4 of a reactor pressure container 1. A connecting port 18 is provided at one portion of the skirt 4 and a lid 19 for switching the connecting port 18 is mounted to the skirt 4 so that it can be rotated. A partial coolant flow jetted from the spray pipe 15 pushes the lid 19 toward the outside. Other coolants hit against the lower mirror part of the reactor pressure container 1 to cool it, thus cooling the lower mirror part of the reactor pressure container 1 which tends to get hot at the time when an emergency reactor cooling system abnormally does not operate due to the accidental loss of a cooling material. At this time, the lid 19 opens so that generated steam passes through the connecting port 18 and is discharged outside the skirt 4, thus improving the efficiency for removing heat at the lower mirror part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor plant, and more particularly to a nuclear reactor plant equipped with a reactor cooling facility suitable for cooling a reactor pressure vessel of a boiling water reactor.

[0002]

2. Description of the Related Art The atmosphere in the containment vessel of a boiling water reactor is cooled by the containment ventilation air-conditioning system during normal operation of the reactor to suppress the temperature rise in the containment vessel. The containment vessel air conditioning system has, as its main components, a cooler for cooling the gas in the containment vessel and a fan for supplying the gas in the containment vessel to the cooler.

A conventional containment vessel ventilation air conditioning system is disclosed in Japanese Patent Laid-Open No. 5-3.
As described in Japanese Patent No. 5835, the shield wall surrounding the reactor pressure vessel, the side surface of the lower pedestal cavity of the reactor pressure vessel (hereinafter referred to as pedestal), and the skirt supporting the reactor pressure vessel. Each has a communication port, and one cooler is provided in the upper part of the storage container.

[0004]

In the conventional containment air conditioning system, the temperature inside the containment vessel is controlled by the cooler during the normal operation of the reactor. However, this air conditioning system does not cool the inside of the reactor pressure vessel and the inside of the containment vessel in the event that the temperature rises abnormally to the reactor pressure vessel. An event in which the pressure inside the PCV abnormally increases and the PCV ventilation air conditioning system cannot be used (for example, the pressure in the PCV exceeds the rated discharge pressure of the fan of the air conditioning system).
In the above, the function of supplying the gas in the storage container by the fan to the cooler is lowered, and the cooling function is also lowered.

It is an object of the present invention to provide a reactor plant capable of cooling a reactor vessel even when a loss of coolant accident occurs and the emergency core cooling system does not operate abnormally.

Another object of the present invention is to provide a reactor plant capable of efficiently removing heat from a reactor vessel.

[0007]

Means for Solving the Problems The features of the present invention that achieve the above objects are that a reactor vessel is disposed in a containment vessel and is installed in a pedestal through an annular skirt, and the reactor vessel is surrounded. The heat insulating material thus provided and the spray means for spraying the cooling water on the outer wall surface of the reactor vessel provided in the skirt are provided.

By providing the above-mentioned spray means,
It is possible to cool the lower mirror part of the reactor vessel, especially the lower mirror part of the reactor vessel in the skirt. This means that the lower mirror section of the reactor vessel, which is likely to reach a high temperature, can be cooled in the state where the emergency core cooling system does not operate abnormally due to the loss of coolant accident.

The features of the present invention for achieving the above-mentioned other objects are as follows.
A reactor vessel placed in the containment vessel and installed in the pedestal via an annular skirt, a heat insulating material provided so as to surround the periphery of the reactor vessel, and a reactor vessel provided in the skirt. A spray means for spraying cooling water is provided on the outer wall surface, a communication opening is provided in a part of the skirt, and a lid for opening and closing the communication opening is rotatably provided on the skirt, and a jet is jetted toward the lid. The means is provided in the spray means.

The jet stream jetted from the jet jetting means provided in the spray means hits the lid rotatably provided on the skirt, so that the lid is opened and the cooling water jetted from the spray means hits the reactor vessel. The steam generated thereby is discharged to the outside of the skirt through the communication port of the skirt. By releasing the steam generated in the skirt to the outside, heat is not trapped in the skirt, and the heat of the reactor vessel can be efficiently removed by the spray means.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A reactor plant which is a preferred embodiment of the present invention applied to a boiling water reactor is shown in FIGS.
This will be described below with reference to FIGS. 3 and 4. The nuclear power plant of this embodiment includes a reactor cooling facility described later.

The reactor pressure vessel 1 is arranged in a dry well 42 inside the containment vessel 5. This reactor pressure vessel 1
It is installed on the pedestal 40 by the skirt 4 provided at the bottom of the reactor pressure vessel 1. Skirt 4
It has an annular shape. A cylindrical reactor shielding wall 3 is installed on the pedestal 40 and surrounds the reactor pressure vessel 1. The heat insulating material 2 is arranged inside the reactor shield wall 3 and surrounds the entire circumference of the reactor pressure vessel 1. Skirt 4
The inner space 43 is a substantially sealed space surrounded by the reactor pressure vessel 1 and the heat insulating material 2 located at the lower end portion. The control rod drive device housing 20 provided on the lower mirror of the reactor pressure vessel 1 extends downward through the heat insulating material 2 located at the lower end. A pressure suppression chamber 41 filled with pool water 32 is provided in the storage container 5 below the dry well 42. A spray nozzle 24 for injecting water into the storage container 5 is installed in the dry well 42.

The nuclear reactor cooling equipment comprises a controller 11, a pump 12 and a spray pipe 15. Spray piping 15
Are arranged in the space 43 and attached to the lower end of the reactor pressure vessel 1. The spray pipe 15 is connected to the tank 14 filled with water by the pipe 16. Pump 1
2 and the valve 13 are provided in the pipe 16. The water gauge 6
It is provided in the reactor pressure vessel 1. The thermometer 7 has a space 43
Inside, it is attached to the outer surface of the reactor pressure vessel 1. The gamma ray monitor 8 is provided in the dry well 42. Reference numeral 9 is a combustible gas detector, 10 is a push button provided on an operation panel (not shown), and 11 is a control device.
A communication port 18 is provided in the skirt 4. Plural communication ports 18 may be provided. A lid 19 for opening and closing the communication port 18 is attached to the skirt 4 so as to be openable and closable. The heat insulating material 2 is installed on the reactor shield wall 3 side of the lid 19. The lid 19 is closed during the normal operation of the nuclear reactor in order to perform a heat retaining function.

The detailed structure of the spray pipe 15 will be described below with reference to FIGS. 2 and 3. The spray pipe 15 has an annular pipe 44, and a short pipe 21 connected to the inside of the annular pipe 44 and arranged between the control rod drive device housings 20.
The short tube 21 extends toward the reactor pressure vessel 1 and has an opening 45 at its tip. The nozzle 22 is provided inside the annular pipe 44 toward the reactor pressure vessel 1.
The nozzle 23 is provided above the short tube 21 and faces the reactor pressure vessel 1. The nozzle 17 faces the lid 12 and is provided outside the annular pipe 44.

In a boiling water reactor, it is assumed that core cooling will be insufficient. For example, the cooling water in the reactor pressure vessel 1 passes through the damaged portion of the recirculation system through the dry well
Reactor pressure vessel 1
This is an event in which a safety system such as an emergency core cooling system that supplies cooling water to the inside does not function and the cooling water in the reactor pressure vessel 1 is lost. In such a case, the cooling water is not supplied into the reactor pressure vessel 1 and the temperature of the lower part of the reactor pressure vessel 1 rises. Especially, the temperature becomes highest near the lower mirror of the reactor pressure vessel 1.

When the above event occurs, the controller 11
Opens the valve 13 and activates the pump 12 based on the interlock shown in FIG. 3 in this interlock
0 and 31 are AND circuits. The control device 11 inputs the measured values of the water level gauge 6, the thermometer 7, the gamma ray monitor 8 and the combustible gas detector 9. This control device 11
The reactor water level measured by the water level gauge 6 is lower than the lower end of the core (below the reactor water level BAF), the temperature of the lower wall of the reactor pressure vessel measured by the thermometer exceeds 280 ° C, and the gamma ray monitor 8 When the measured radiation level in the dry well 42 becomes 10 times or more of the normal level and the hydrogen concentration in the dry well 42 measured by the combustible gas detector 9 reaches a predetermined level (high hydrogen concentration), the activation is started. Generate a permission signal. The activation permission signal is displayed on a display device (not shown) provided on the operation panel (not shown). The operator confirms that the activation permission signal is displayed, and then pushes the button 1
Press 0 (button ON signal is generated). By the generation of the activation permission signal and the generation of the button ON signal, the control device 11 causes the valve 1
An open signal is output to 3 and a start signal is output to the pump 12. These open the valve 13 and start the pump 12.

When the pump 12 is started, the cooling water in the tank 14 reaches the spray pipe 15 via the pipe 16. A part of the cooling water is jetted from the nozzle 17 toward the lid 19. The lid 19 is pushed down toward the outside of the skirt 4 by this jet of water. Space 43
The hot gas therein flows out through the communication port 18 into the annular space 46 formed between the heat insulating material 2 and the reactor shield wall 3.

Most of the cooling water guided to the spray pipe 15 is jetted from the nozzles 22 and 23 and the opening 45 toward the wall of the reactor pressure vessel 1 to cool the lower mirror of the reactor pressure vessel 1 from the outer surface. To do. The cooling water that hits the reactor pressure vessel 1 removes heat from the high-temperature reactor pressure vessel 1 to become steam. This water vapor passes through the communication port 18 and the annular space 46.
Reach The water vapor rises in the annular space 46, is guided to the dry well 42, and is cooled by the cooling water ejected from the spray nozzle 24 to become water. The steam rises while also taking heat from the heat insulating material 2 and the reactor pressure vessel 1 when rising in the annular space 46.

When the coolant in the reactor pressure vessel 1 is lost and the emergency core cooling system is in an abnormal state and does not operate, cooling cannot be performed from the inside of the reactor pressure vessel 1. In such a case, core cooling becomes insufficient and the reactor pressure vessel 1
The temperature of the lower mirror part of the machine becomes very high. According to the present embodiment,
Since the cooling water is jetted from the nozzles 22 and 23 of the spray pipe 15 and the opening 45, even if the coolant in the reactor pressure vessel 1 is lost and the emergency core cooling system becomes abnormal and does not operate, the reactor pressure vessel The lower mirror part of 1 can be cooled. The control device 11 controls not only the state quantity in the dry well 42, but also the decrease in the water level in the reactor pressure vessel 1 below the set water level and the reactor pressure, which indicate the high temperature in the reactor pressure vessel 1. The jetting of the cooling water from the spray pipe 15 is controlled in consideration of the rise of the temperature of the lower mirror portion of the vessel 1 to the set temperature or higher, so that the reactor pressure vessel 1 is mistakenly operated during normal operation of the reactor. It is possible to avoid irrigation of the lower mirror part.

Since the lid 19 is opened outward by the jet flow ejected from the nozzle 17 to the spray pipe 15, the cooling water ejected from the spray pipe 15 is generated by hitting the lower mirror portion of the reactor pressure vessel 1. The steam is discharged into the annular space 46 through the communication port 18 of the skirt 4. Due to the release of the steam generated in the skirt 4 to the outside, heat is not trapped in the space 43 in the skirt 4, and the heat removal of the lower mirror portion of the reactor pressure vessel 1 by the spray pipe 15 is efficiently performed. It can be carried out. Further, the steam flowing out from the communication port 18 cools the side wall portion of the reactor pressure vessel 1 via the heat insulating material 2 while rising in the annular space 46.

A nuclear power plant which is another embodiment of the present invention will be described with reference to FIG. In this embodiment, the tank 14 in the embodiment of FIG. 1 is removed, and the portion of the pipe 16 upstream of the pump 12 is connected to the pressure suppression chamber 41. Other configurations of the present embodiment are the same as those of the embodiment of FIG. The controller 11 functions to activate the pump 12, and the valve 1
When 3 is opened, the pool water 32 in the pressure suppression chamber 41 is supplied to the spray pipe 1 through the pipe 16. Also in this embodiment, the lower mirror portion of the reactor pressure vessel 1 is cooled and the lid 16 is opened in the same manner as the embodiment of FIG.

This embodiment produces the same effect as the embodiment of FIG.

[0023]

According to the first aspect of the present invention, the lower mirror portion of the reactor vessel, which is likely to reach a high temperature, can be cooled in a state where the coolant loss accident occurs and the emergency core cooling system does not operate abnormally. Therefore, it is possible to suppress the temperature rise of the lower mirror portion of the reactor vessel.

According to the invention of claim 2, in addition to the effect obtained by claim 1, heat can be efficiently removed from the reactor vessel by the spray means without keeping heat in the skirt. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a reactor cooling facility that is a preferred embodiment of the present invention.

FIG. 2 is a detailed configuration diagram of the spray pipe of FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an explanatory diagram showing a logic of the control device of FIG. 1.

FIG. 5 is a configuration diagram of a reactor cooling facility which is another embodiment of the present invention.

[Explanation of symbols]

1 ... Reactor pressure vessel, 2 ... Heat insulating material, 3 ... Reactor shielding wall,
4 ... Skirt, 5 ... Storage container, 6 ... Water level gauge, 7 ... Thermometer, 8 ... Gamma ray monitor, 9 ... Combustible gas detector, 1
1 ... Control device, 12 ... Pump, 14 ... Tank, 15 ... Spray piping, 16 ... Piping, 17, 22, 23 ... Nozzle,
18 ... Communication port, 19 ... Lid, 21 ... Short tube, 40 ... Pedestal, 41 ... Pressure suppression chamber, 42 ... Drywell.

Claims (4)

[Claims] 1. A reactor vessel arranged in a containment vessel and installed in a pedestal through an annular skirt, a heat insulating material provided so as to surround the periphery of the reactor vessel, and a heat insulating material provided in the skirt. A nuclear reactor plant comprising: spray means for spraying cooling water on an outer wall surface of the reactor vessel. 2. A reactor vessel arranged in a containment vessel and installed in a pedestal via an annular skirt, a heat insulating material provided so as to surround the periphery of the reactor vessel, and a heat insulating material provided in the skirt. A spray means for spraying cooling water is provided on the outer wall surface of the reactor vessel, a communication opening is provided in a part of the skirt, and a lid for opening and closing the communication opening is rotatably provided on the skirt and faces the lid. A reactor plant characterized in that a spray means is provided in the spray means. 3. The nuclear reactor plant according to claim 2, wherein a heat insulating material is attached to the outside of the lid. 4. The reactor water level is below a first set value, the wall temperature of the lower part of the reactor vessel is below a second set value, the radioactivity level in the dry well is below a third set value, and dry. The control means for generating a signal for permitting the supply of the cooling water to the spray means when the hydrogen concentration in the well becomes equal to or lower than the fourth set value and a manual start signal is generated. 2 reactor plants.