JP2012230032A - Cooling device for reactor containment vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a passive cooling device for a reactor containment vessel, which can maintain pressure reduction and heat removal capabilities of a reactor and the reactor containment vessel over a long period.SOLUTION: A cooling device for a reactor containment vessel includes: a building 3 containing a reactor containment vessel 2; a static containment vessel cooling device 10 installed on a ground surface outside the building 3; a heat exchanger chamber 11 which is installed adjacent to the static containment vessel cooling device 10 and in which a heat exchanger 12 and a drain chamber 13 are arranged; a heat transfer pipe 18 of the heat exchanger 12, which is arranged at a lower part in the static containment vessel cooling device 10; a vapor release pipe 7 connecting the inside of the reactor containment vessel 2 to the heat exchanger 12; and a seawater introduction pipe 22 connected to a bottom of the static containment vessel cooling device 10 via a check valve 23. The heat transfer pipe 18 is positioned lower than a low water level at low tide.

Description

  The present invention relates to a reactor containment vessel cooling apparatus, and more particularly, to a reactor containment vessel cooling apparatus including a static containment vessel cooling apparatus.

  When the coolant is released into the reactor containment vessel due to the breakage of the primary system piping or the opening of the pressure reducing valve in a nuclear power plant, the coolant becomes high-temperature steam due to decompression, so the pressure inside the reactor containment vessel rises. To do. Conventionally, in order to suppress the pressure rise and ensure the soundness of the containment vessel, the generated steam is guided to the pressure suppression pool in the containment vessel to condense, or the upper part of the containment vessel is sprayed into the containment vessel spray to A method for condensing the water is known. In these methods, heat accumulated in the pressure suppression pool and spray water is finally released to the outside through a heat exchanger by a dynamic device such as a pump.

  In recent years, in order to improve the reliability of safety systems, the pressure suppression method inside the containment vessel is not a dynamic device as in the past, but an isolation capacitor (IC) or static containment inside or outside the containment vessel. Methods have been proposed in which a container cooling system (PCCS) is provided to remove heat from the containment vessel using a naturally occurring passive force such as gravity as a driving force (Patent Documents 1 and 2).

JP-A-8-201559 JP 2009-74980 A

  In the cooling device using the conventional passive driving force described above, the isolation condenser pool and the PCCS cooling water have a sufficient amount of water having a heat removal capability of about three days in a full state. However, if the cooling water in the static containment vessel cooling system leaks due to a crack due to an earthquake or the like, or if the heat removal period is prolonged, additional water supply is required. Additional water supply may be difficult due to access restrictions due to high radiation environment.

  In such a case, it is difficult to remove heat and reduce pressure in the containment vessel, and the atmosphere inside the containment vessel may be forced to be released to the outside (containment vessel vent), or the residual heat removal function in the nuclear reactor may be lost.

  The present invention has been made to solve the above-mentioned problems, and provides a passive reactor containment vessel cooling apparatus capable of performing depressurization and heat removal of the reactor and the containment vessel over a long period of time in the event of an accident. The purpose is to do.

  In order to solve the above problems, a reactor containment vessel cooling device according to the present invention includes a building containing the reactor containment vessel, a static containment vessel cooling device installed on the ground surface outside the building, A heat exchanger chamber that is provided adjacent to the static containment vessel cooling device and in which a heat exchanger and a drain chamber are arranged, and a heat exchanger that is arranged in the lower part of the static containment vessel cooling device. An atom having a heat pipe, a steam escape pipe connecting the inside of the reactor containment vessel and the heat exchanger, and a seawater introduction pipe connected to a lower part of the static containment vessel cooling device via a check valve A cooling apparatus for a furnace containment vessel, wherein the heat transfer tube is located below a low tide water level at low tide.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure reduction and heat removal function of a reactor containment vessel and a pressure vessel can be maintained over a long period of time by the passive cooling system using seawater, gravity, etc. In addition, since the static containment vessel cooling device is installed on the ground surface, additional water supply can be easily performed in the event of an accident, and even when it is difficult to supply additional water in a highly radioactive environment, water supply using seawater is possible. Can continue automatically.

The whole block diagram of the cooling device of the reactor containment vessel concerning a 1st embodiment. The whole block diagram of the reactor containment vessel cooling device according to the second embodiment. The block diagram of the principal part of the cooling device of the reactor containment vessel which concerns on 3rd Embodiment. (A) is a block diagram of the static container cooling device which concerns on 4th Embodiment, (b) and (c) are the block diagrams which show the modification.

  Hereinafter, an embodiment of a reactor containment vessel cooling apparatus according to the present invention will be described with reference to the drawings.

[First Embodiment]
A reactor containment vessel cooling apparatus according to the first embodiment will be described with reference to FIGS.
(Constitution)
As shown in FIG. 1, the reactor containment vessel cooling apparatus according to the first embodiment includes a pressure vessel 1, a reactor containment vessel 2 provided around the pressure vessel 1, and a reactor containment vessel 2. The building 3 to be included, the pressure suppression chamber 4 filled with pressure suppression water, the main steam pipe 5 for guiding the steam generated in the pressure vessel 1 to a turbine (not shown), and the decompression provided in the main steam pipe 5 Heat exchange with a valve 9, a water supply pipe 6, a static containment vessel cooling device 10 installed on the ground surface outside the building 3 and filled with cooling water, a heat exchanger 12 and a drain chamber 13 It is comprised from the chamber 11.

  The inside of the containment vessel 2 and the heat exchanger 12 are connected by a steam escape pipe 7, and the drain chamber 13 is connected to, for example, a water supply pipe 6 through a check valve, and the drain water in the drain chamber 13 is pressurized in an emergency. It is comprised so that water can be supplied to the container 1.

  A seawater introduction pipe 22 is connected to the lower part of the static containment vessel cooling apparatus 10 and communicates with seawater via a check valve 23, an on-off valve 24, and a foreign matter removal filter 40. The check valve 23 is configured to open only in the direction of the static containment container cooling device 10 from the sea.

  Further, the static containment vessel cooling apparatus 10 is provided with a water supply port 26 for replenishing cooling water, and a discharge pipe for discharging the steam in the static containment vessel cooling apparatus 10 to the outside through a filter 21 for capturing radioactive substances. 20 is installed. In addition, a plurality of heat transfer tubes 18 of the heat exchanger 12 are arranged in the lower part of the static containment vessel cooling apparatus 10 to condense the steam introduced through the steam escape tube 7, and the condensed drain water is discharged into the drain chamber 13. Led to.

When seawater is introduced into the static containment vessel cooling apparatus 10, the heat transfer tube 18 is disposed at the lower part of the static containment vessel cooling apparatus 10 so as to be positioned below the low tide level LL of the seawater.
In addition, the static containment vessel cooling apparatus 10 and the heat exchanger chamber 11 in which the heat exchanger 12 and the drain chamber 13 are installed are all formed of an airtight radiation shield.

  In the example of FIG. 1, the static containment vessel cooling apparatus 10 has a semi-underground structure. However, if the heat transfer pipe 18 is located below the low tide water level LL, the entire structure may be an underground structure or an above-ground structure. Good. Further, the on-off valve 24 provided in the seawater introduction pipe 22 can be omitted.

(Function)
In the reactor containment vessel cooling apparatus configured as described above, when the coolant is discharged into the reactor containment vessel 2 through the pressure reducing valve 9 or the release valve (not shown) in the event of an accident, the pressure rises. The steam in the reactor containment vessel 2 is led to the pressure suppression chamber 4 and condensed. Eventually, when the water temperature in the pressure suppression chamber 4 reaches the saturation temperature, the pressure suppression function is lost, and instead, the static containment vessel cooling device 11 begins to function, and the steam in the reactor containment vessel 2 passes through the steam escape pipe 7. The steam is led to the heat exchanger 12 and the heat transfer pipe 18 to condense the steam.
As a result, the reactor containment vessel 2 is depressurized and heat-removed, and a situation in which steam is directly released to the outside (a containment vessel vent) is prevented.

The static containment vessel cooling device 10 is usually filled with cooling water consisting of fresh water. However, if the cooling water leaks due to cracks or the like, or if the heat removal period is prolonged, the level of the cooling water is reduced. Then, additional cooling water is replenished through a water supply port 26 from a water supply facility (not shown) such as a water supply vehicle or a water supply tank.
The drain water stored in the drain chamber 13 is injected into the pressure vessel 1 by gravity through the water supply pipe 6 and the like to remove residual heat of the reactor.

Thus, since the static containment vessel cooling apparatus 10 is installed on the ground surface, it becomes possible to easily perform additional water supply in the event of an accident.
The drain water is not limited to the water supply pipe 6 and may be connected to a pipe such as a high-pressure or low-pressure core water injection system.

  On the other hand, if the surroundings of the building 3 are difficult to access due to a high radiation environment, or if an external water supply tank (not shown) is damaged and additional water supply becomes difficult, Cooling water level decreases. Then, the check valve 23 is opened due to the water head difference, and the seawater flows into the static containment vessel cooling apparatus 10 through the seawater introduction pipe 22. At that time, since the heat transfer pipe 18 in the static containment vessel cooling device 10 is below the low tide water level LL even at low tide, the steam introduced from the steam escape pipe 7 can be continuously decompressed and condensed. it can.

  Further, the open / close valve 24 may be installed in the seawater introduction pipe 22 for maintenance work of the check valve 23 and the seawater introduction pipe 22 or the like. At that time, the on-off valve 24 is opened or closed by the on-off valve driving unit 25 by remote operation or manually.

  Furthermore, when the inside of the static containment vessel cooling apparatus 10 is filled with fresh water during normal times, the on-off valve 24 is closed during normal times, and a decrease in the cooling water level in the static containment vessel cooling apparatus 10 is detected. The on-off valve 24 may be operated so as to open when additional water supply of fresh water becomes difficult.

  Moreover, since the static containment vessel cooling device 10 is installed on the ground surface, the seawater does not overflow from the static containment vessel cooling device 10 even when the seawater is at the high tide level FL. In addition, if the sea level rises above the ground surface due to a tsunami or storm surge, the sea water is released to the outside from the static containment vessel cooling device 10 through the discharge pipe 20, but the heat removal of the reactor containment vessel Does not affect functionality.

  Further, the coolant in the static containment vessel cooling apparatus 10 becomes high temperature due to heat exchange and generates steam, but the steam is discharged to the outside from the discharge pipe 20 through the filter 21 that captures the radioactive substance. In addition, the tip of the discharge pipe 20 has, for example, an inverted U-shaped structure or a snorkel shape (not shown) in which the side portions of both ends of the open pipe are connected to the tip of the discharge pipe 20 so that rainwater and foreign matters do not enter from the outside. .

(effect)
As described above, according to the present embodiment, the pressure reduction / heat removal function of the reactor containment vessel and the pressure vessel can be maintained over a long period of time by the passive cooling system using gravity and seawater. In addition, since the static containment vessel cooling device is installed on the ground surface, additional water supply can be easily performed in the event of an accident, and even when additional water supply is difficult, water supply using seawater is automatically continued. Can do. Further, the drain water stored in the drain chamber can be continuously supplied as cooling water for the pressure vessel.

  Furthermore, the static containment vessel cooling apparatus of the present embodiment can be installed not only in a new installation but also in an existing nuclear power plant without requiring a large-scale construction, thereby improving the safety and reliability of the nuclear power plant. be able to.

[Second Embodiment]
A reactor containment vessel cooling apparatus according to a second embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.

  In the first embodiment, the drain water in the drain chamber 13 can be supplied to the reactor pressure vessel 1 by gravity, but the pressure vessel 1 of the second embodiment is at a position higher than the ground surface and is used for water supply. Since gravity cannot be used, drain water is supplied to the reactor pressure vessel 1 by a pump 15 driven by an emergency power source.

  In the second embodiment, the pump chamber 14 in which the pump 15 is installed is installed adjacent to the heat exchanger chamber 11. The pump 15 is driven by an emergency power source (not shown) such as a diesel generator or a battery. The emergency power source is installed in an appropriate place in or around the pump chamber 14.

  In the cooling device configured as described above, the static containment vessel cooling device 10 operates in the same manner as in the first embodiment in the event of an accident. The drain water stored in the drain chamber 13 is supplied into the reactor pressure vessel 1 by a pump 15 driven by an emergency power source.

  According to the second embodiment, in addition to the effects of the first embodiment, even when gravity cannot be used for supplying drain water, the drain water is injected into the reactor pressure vessel by the emergency power source. Heat removal from the pressure vessel can be continued for a long time.

[Third Embodiment]
A reactor containment vessel cooling apparatus according to a third embodiment will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.
The third embodiment is characterized in that a small steam turbine that generates electric power using steam discharged from the static containment vessel cooling apparatus 10 is used as a drive source of the pump 15.

  In the present embodiment, the steam turbine 31 is disposed in a turbine chamber 30 installed adjacent to the static containment vessel cooling apparatus 10, and the steam released from the static containment vessel cooling apparatus 10 is passed through the steam discharge pipe 32. Then, the electric power generated by a generator (not shown) connected to the rotating shaft of the steam turbine 31 is supplied to the pump 15 via the cable 34 to drive the pump 15. Further, the water condensed in the steam turbine 31 is returned to the static containment vessel cooling apparatus 10 through the pipe 33, and the non-condensed gas is discharged to the outside through the filter 21 and the discharge pipe 36.

  According to the third embodiment, in addition to the effects of the second embodiment, by using the discharge steam from the static containment vessel cooling apparatus 10, the drain water is supplied to the reactor pressure without using an external power source. It can be injected into the vessel and heat removal from the reactor pressure vessel can be continued for a long time.

[Fourth Embodiment]
A reactor containment vessel cooling apparatus according to a fourth embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the structure same as the said embodiment, and the overlapping description is abbreviate | omitted.
The fourth embodiment is characterized in that, instead of providing the check valve 23 in the seawater introduction pipe 22, an open / close valve that opens and closes by a float is provided.

In FIG. 4A, an open / close rod 50 having a float 51 at the upper end and a closing portion 52 attached at the lower end is arranged inside the static containment vessel cooling apparatus 10.
In the present embodiment configured as described above, when the water level is normal, the closing portion of the opening / closing rod 50 is in the closing position, and the seawater is prevented from flowing into the static containment vessel cooling apparatus 10.

  On the other hand, when the water level of the coolant in the static containment vessel cooling device 10 is lowered, the opening / closing rod 50 is lowered and the closing portion is moved to the open position to allow the inflow of seawater.

  In the modification of FIG. 4B, a latch portion 53 is provided on the opening / closing rod 50. After the closing portion 52 moves to the open position as the water level decreases, the latch portion 53 functions to maintain that state. Can stably flow into the static containment vessel cooling apparatus 10.

  FIG. 4C is a modification of the closing portion, and the opening / closing rod 50 is provided with a flat closing portion 54 that opens and closes the outlet of the seawater introduction pipe 22.

  According to the fourth embodiment, by using an on-off valve that operates in conjunction with the coolant level in the static containment vessel cooling apparatus 10, seawater is contained in the static containment vessel cooling apparatus 10 when the water level drops. It can be surely introduced.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Reactor containment vessel, 3 ... Building, 4 ... Pressure suppression chamber, 5 ... Main steam pipe, 6 ... Water supply pipe, 7 ... Steam escape pipe, 10 ... Static containment vessel cooling device, DESCRIPTION OF SYMBOLS 11 ... Heat exchanger chamber, 12 ... Heat exchanger, 13 ... Drain chamber, 14 ... Pump chamber, 15 ... Pump, 18 ... Heat transfer pipe, 19 ... Piping, 20 ... Exhaust pipe, 21 ... Filter, 22 ... Seawater introduction piping , 23 ... Check valve, 24 ... Open / close valve, 25 ... Open / close valve drive unit, 30 ... Turbine chamber, 31 ... Small steam turbine, 32 ... Steam discharge pipe, 33 ... Pipe, 34 ... Cable, 35 ... Filter, 36 ... Discharge pipe, 40 ... foreign matter removal filter, 50 ... open / close rod, 51 ... float, 52, 54 ... closing part, 53 ... latch part.

Claims (8)

A building containing the reactor containment vessel, a static containment vessel cooling device installed on the ground surface outside the building, a heat exchanger and a drain chamber provided adjacent to the static containment vessel cooling device A heat exchanger chamber disposed in the static containment vessel cooling device, a heat transfer tube of the heat exchanger disposed in a lower part of the static containment vessel cooling device, and steam connecting the inside of the reactor containment vessel and the heat exchanger A reactor containment vessel cooling apparatus having an escape pipe and a seawater introduction pipe connected to a lower part of the static containment vessel cooling apparatus via a check valve,
The reactor containment vessel cooling apparatus, wherein the heat transfer tube is located below a low tide water level at low tide.   2. The reactor containment vessel cooling apparatus according to claim 1, wherein the drain water in the drain chamber is supplied to the reactor pressure vessel by gravity.   2. The reactor containment vessel cooling apparatus according to claim 1, wherein a pump chamber is provided adjacent to the drain chamber, and drain water is supplied to the pressure vessel by a pump in the pump chamber.   4. The reactor containment vessel cooling apparatus according to claim 3, wherein the pump is driven by an emergency power source.   A turbine chamber is provided adjacent to the static containment vessel cooling device, a turbine in the turbine chamber is driven by steam discharged from the static containment vessel cooling device, and the pump is driven by electric power generated by the turbine. The reactor containment vessel cooling apparatus according to claim 3.   Instead of the check valve, an open / close rod having a float at the upper end and a closing portion at the lower end for blocking or allowing the inflow of seawater from the seawater introduction pipe is disposed in the static containment vessel cooling device. The reactor containment vessel cooling apparatus according to any one of claims 1 to 5.   7. The reactor containment vessel cooling apparatus according to claim 6, wherein a latch portion for latching movement of the open / close rod is provided in the open / close rod.   The reactor containment vessel cooling apparatus according to any one of claims 1 to 7, wherein an opening / closing valve is provided in the seawater introduction pipe.

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