JP2015227830A - Cooling system of reactor container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system of a reactor container capable of suppressing pressurization to the reactor container without enlarging a reactor building containing the periphery pool and the reactor container and capable of statically cooling the reactor building for a long period.SOLUTION: A cooling system of a reactor containment vessel 3 accommodates a reactor pressure vessel incorporating a reactor core 1, and includes: an outer periphery pool 12 for storing cooling water in the space between a wall surface part 11 provided via a gap on the outer periphery side of the reactor containment vessel 3 and the reactor containment vessel 3; an auxiliary water supply tank 15 disposed outside of the wall surface part 11 and supplying water to an outer periphery pool 12; a connection pipe 16 for communicating the outer periphery pool 12 and the auxiliary water supply tank 15; and a water supply adjustment valve 20 provided in the connection pipe 16 and adjusting a supply water amount from the auxiliary water supply tank 15 to the outer periphery pool 12 on the basis of a water level of the outer periphery pool 12.

Description

  The present invention relates to a nuclear reactor containment cooling system, and more particularly to a system for statically cooling a reactor containment vessel in the event of an accident such as loss of all AC power.

  In the conventional improved boiling water reactor (ABWR), steam generated in the reactor pressure vessel by decay heat generated in the core after the reactor scram is introduced into the suppression pool in the reactor containment vessel and condensed. Thus, pressurization of the reactor pressure vessel and the reactor containment vessel is prevented. At the same time, the reactor isolation cooling system pump is driven by the steam introduced into the suppression pool, and the pump is used to pump the cooling water from the suppression pool and inject it into the reactor pressure vessel, thereby submerging and cooling the core. Is maintained.

  In this way, the decay heat generated in the core moves from the reactor pressure vessel to the reactor containment vessel. When the residual heat removal system pump is in operation, the cooling water of the suppression pool that has become hot due to the transfer of decay heat is sent to the heat exchanger outside the reactor containment vessel, and collapsed via the heat exchanger. By removing heat outside the system, the temperature and pressure of the reactor containment vessel are prevented from rising. However, if the residual heat removal system cannot be operated due to loss of all AC power, etc., the temperature and pressure of the reactor containment will rise gradually over the long term, affecting the containment function of radioactive materials in the containment. There is a fear.

  Therefore, for example, a system described in Patent Document 1 is proposed as a system that statically cools the reactor containment vessel and eliminates decay heat without using dynamic equipment such as a pump in the event of loss of all AC power, etc. Has been. In the system described in Patent Document 1, an outer peripheral pool is provided around the outer periphery of a steel reactor containment vessel, the surface of the reactor containment vessel is used as a heat transfer surface, and the outer pool is heated by a temperature difference between the suppression pool and the outer peripheral pool. In the end, the vapor of the pool water in the outer peripheral pool is discharged to the outside. This system can also supply a part of the cooling water from the cooling water pool of the gravity drop type emergency core cooling system installed on the upper part of the concrete structure wall to the outer peripheral pool, and raise the water level of the outer peripheral pool in the event of an accident. The heat dissipation characteristics of the outer pool are improved.

Japanese Patent Laid-Open No. 04-125495

  When the reactor containment vessel is statically cooled using the outer peripheral pool as in the system described in Patent Document 1 described above, the cooling function of the outer peripheral pool is lost when the entire amount of pool water in the outer peripheral pool evaporates. . Therefore, in order to maintain the cooling of the reactor containment vessel for a long time, it is conceivable to increase the amount of water stored in the outer peripheral pool. As this measure, the water level of the outer peripheral pool is set high in advance or the outer peripheral pool is expanded outward.

  When the water level of the outer peripheral pool is set high, a pressure corresponding to the head of water that has been increased is applied to the outer wall surface of the reactor containment vessel. Therefore, from the viewpoint of preventing excessive pressurization to the reactor containment vessel, there is a limit to increasing the amount of water stored in the outer pool by increasing the water level, and the amount of water that can cool the reactor containment vessel for a long period of time. It is difficult to ensure.

  On the other hand, when the outer peripheral pool is extended to the outside, the size of the reactor building that encloses the outer peripheral pool is increased, which causes problems such as a longer construction period and increased construction costs. In particular, in the case of a small-to-medium reactor that is expected to employ an outer peripheral pool, an increase in the size of the reactor building may greatly damage the advantage of a short construction period of the small-to-medium reactor.

  Further, when the reactor containment vessel is statically cooled using the outer peripheral pool, when the pool water in the outer peripheral pool reaches the boiling point, the heat of the reactor containment vessel is transmitted by boiling heat transfer. Since boiling heat transfer can remove heat more efficiently than convective heat transfer of pool water before reaching the boiling point, the amount of heat that can be removed after reaching the boiling point increases. For this reason, the small outer peripheral pool is advantageous because the time to reach the boiling point of the pool water is faster and the cooling capacity is higher than the large one.

  Thus, there are many disadvantages when trying to increase the amount of water stored in the outer peripheral pool itself in order to maintain the cooling of the reactor containment vessel for a long period of time.

  Therefore, water supply to the outer peripheral pool can be considered to enable long-term cooling of the reactor containment vessel without increasing the outer peripheral pool. In consideration of the loss of all AC power, it is desirable that water supply to the outer pool can be performed without using a dynamic device such as a pump. Further, when the water level of the outer peripheral pool rises due to the water supply to the outer peripheral pool, the pressure corresponding to the raised head is applied to the reactor containment vessel, similarly to the case where the water level of the outer peripheral pool is set high. Therefore, it is necessary to limit the amount of water supplied to the outer peripheral pool and suppress the pressurization to the reactor containment vessel.

  In the system described in Patent Document 1 described above, a part of the cooling water of the cooling water pool of the gravity drop type emergency core cooling system provided on the upper part of the concrete structure wall is supplied to the outer peripheral pool by gravity. For this reason, in order to enable long-term cooling of decay heat, a large-capacity cooling water pool that can hold the amount of water that can be replenished for a long period of time to the outer peripheral pool in addition to the amount of water for core cooling is placed above the concrete structure wall There is a need. However, it is difficult to arrange such a large-capacity cooling water pool on the upper part of the concrete structure wall because of seismic performance. Therefore, in this system, a large-capacity cooling water pool cannot be installed, and it is difficult to cool the reactor containment vessel for a long time.

  In addition, when a large-capacity cooling water pool is arranged on the upper part of the concrete structure wall, the reactor containment vessel and the reactor building that contains the reactor containment vessel are enlarged.

  The present invention has been made in order to solve the above-mentioned problems, and the object thereof is to statically cool for a long time without enlarging the reactor building containing the outer peripheral pool and the reactor containment vessel. At the same time, a reactor containment vessel cooling system capable of suppressing pressurization to the reactor containment vessel is provided.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-described problems. For example, a reactor containment vessel cooling system for storing a reactor pressure vessel containing a reactor core, wherein the reactor containment vessel includes: An outer peripheral pool that stores cooling water in a space between a wall surface portion provided on the outer peripheral side with a space therebetween and the reactor containment vessel, and a makeup water tank that is installed outside the wall surface portion and supplies water to the outer peripheral pool And a connection pipe that connects the outer peripheral pool and the makeup water tank, and a water supply adjustment that is provided in the connection pipe and that adjusts the amount of water supplied from the makeup water tank to the outer periphery pool according to the water level of the outer periphery pool And a valve.

According to the present invention, water is supplied from the makeup water tank installed outside the wall surface to the outer peripheral pool by gravity, and the amount of water supplied to the outer peripheral pool is adjusted by the water supply adjustment valve according to the water level of the outer peripheral pool. Without increasing the size of the reactor building that contains the reactor containment vessel, the reactor containment vessel can be statically cooled for a long period of time, and pressurization to the reactor containment vessel can be suppressed. As a result, the safety of the nuclear power plant is improved.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is a schematic configuration diagram showing a nuclear power plant to which a first embodiment of a reactor containment vessel cooling system of the present invention is applied. It is a schematic block diagram which shows the water supply adjustment valve which comprises 1st Embodiment of the cooling system of the reactor containment vessel of this invention shown in FIG. It is explanatory drawing which shows the opening / closing operation | movement of the water supply adjustment valve which comprises 1st Embodiment of the cooling system of the reactor containment vessel of this invention shown in FIG. It is a schematic block diagram which shows 2nd Embodiment of the cooling system of the reactor containment vessel of this invention. It is a schematic block diagram which shows 3rd Embodiment of the cooling system of the reactor containment vessel of this invention. It is a schematic block diagram which shows 4th Embodiment of the cooling system of the reactor containment vessel of this invention.

Embodiments of a reactor containment cooling system according to the present invention will be described below with reference to the drawings.
[First Embodiment]
A first embodiment of a reactor containment cooling system according to the present invention will be described with reference to FIGS.
1 to 3 show a first embodiment of a reactor containment cooling system according to the present invention, and FIG. 1 applies the first embodiment of a reactor containment cooling system according to the present invention. 2 is a schematic configuration diagram showing a nuclear power plant, FIG. 2 is a schematic configuration diagram showing a water supply regulating valve constituting the first embodiment of the reactor containment vessel cooling system of the present invention shown in FIG. 1, and FIG. It is explanatory drawing which shows the opening / closing operation | movement of the water supply adjustment valve which comprises 1st Embodiment of the cooling system of the reactor containment vessel of this invention shown in FIG.

  In FIG. 1, the nuclear power plant includes a reactor pressure vessel 2 that houses a reactor core 1 and a reactor containment vessel 3 that houses the reactor pressure vessel 2. The reactor containment vessel 3 is airtight, and even in the unlikely event that a radioactive substance leaks from the reactor pressure vessel 2, the radioactive substance is retained inside to minimize the influence on the surrounding environment. Is. The reactor containment vessel 3 is made of, for example, steel and has a substantially cylindrical shape.

  The interior of the reactor containment vessel 3 is configured by a dry well 4 surrounding the reactor pressure vessel 2 and a wet well 5 containing a suppression pool 6 provided at the lower part of the reactor containment vessel 3. The dry well 4 and the wet well 5 are partitioned by a diaphragm floor 7 and communicate with each other via a vent pipe 8. The vent pipe 8 guides the steam released into the dry well 4 due to the occurrence of a coolant loss accident or the like to the suppression pool 6.

  A piping (not shown) connected to the reactor pressure vessel 2 is provided with a main steam relief safety valve (not shown). The main steam relief safety valve allows the steam in the reactor pressure vessel 2 to escape to the suppression pool 6 when the pressure in the reactor pressure vessel 2 rises above a certain value.

  The nuclear power plant is provided with a residual heat removal system. The residual heat removal system is roughly composed of a heat exchanger (not shown) arranged outside the reactor containment vessel 3 and a pump (not shown) driven by power supply, and the decay heat generated in the core 1. By transferring the pool water of the suppression pool 6 whose temperature has increased due to the transmission of the water to the heat exchanger outside the reactor containment vessel 3 by a pump, the decay heat is discharged out of the system.

  The nuclear power plant includes a biological shielding wall (wall surface portion) 11 made of concrete that shields radiation disposed on the outer peripheral side of the reactor containment vessel 3 via an interval (for example, about 1 m). The cooling water can be stored in the space between 11 and the reactor containment vessel 3. The biological shielding wall 11 can be configured as a part of the wall surface of the reactor building.

  The nuclear power plant is provided with a reactor containment vessel 3 cooling system including an outer peripheral pool 12 in which cooling water is stored in a space between the reactor containment vessel 3 and the biological shielding wall 11. This cooling system cools the reactor containment vessel 3 by naturally dissipating the decay heat stored in the suppression pool 6 to the cooling water in the outer peripheral pool 12 via the reactor containment vessel 3.

  When the pool water of the suppression pool 6 is cooled by transferring heat to the outer peripheral pool 12 via the reactor containment vessel 3 as in this cooling system, the higher the water level of the outer peripheral pool 12 is, the lower the cooling of the outer peripheral pool 12 is. Since the amount of heat removal increases due to an increase in the contact heat transfer area between water and the reactor containment vessel 3, the water level is preferably as high as possible. However, there is a possibility that the outer wall surface of the reactor containment vessel 3 is excessively pressurized due to a difference in the water head between the cooling water in the outer peripheral pool 12 and the pool water in the suppression pool 6. Therefore, in the present cooling system, the water level of the outer peripheral pool 12 is limited to a preset set value H, for example, a position higher by about 1 m than the water level of the suppression pool 6 (during normal operation). Both suppression of pressurization and increase in contact heat transfer area are achieved.

  A discharge hole 13 that restricts the water level of the outer peripheral pool 12 and discharges the cooling water in the outer peripheral pool 12 to the outside of the biological shield wall 11 at a predetermined height (position higher than the set value H) in the biological shield wall. Is provided. The discharge hole 13 also functions to discharge steam generated in the outer peripheral pool 12 by heat transfer from the suppression pool 6 to the outside of the system and release decay heat to the outside of the system.

  A makeup water tank 15 for supplying water to the outer peripheral pool 12 is installed outside the living body shielding wall 11 in the nuclear power plant. The makeup water tank 15 and the outer peripheral pool 12 are communicated with each other through a connection pipe 16. The makeup water tank 15 is installed on substantially the same plane as the reactor containment vessel 3 (peripheral pool 12), for example. The initial position of the water surface T of the makeup water tank 15 is set to a position higher than the initial position of the water surface P of the outer peripheral pool 12.

  One end of the connection pipe 16 is connected to the lower end of the side surface of the outer peripheral pool 12, and the other end is connected to the lower end of the side surface of the makeup water tank 15. As a result, most of the cooling water stored in the makeup water tank 15 can be supplied to the outer peripheral pool 12.

  The connection pipe 16 is provided with a water supply adjustment valve 20 that adjusts the amount of water supplied from the makeup water tank 15 to the outer peripheral pool 12 according to the water level of the outer peripheral pool 12. The water supply adjustment valve 20 is configured to be closed when the water level of the outer peripheral pool 12 is equal to or higher than a preset set value H, and to be opened when it is less than the set value H.

Next, the configuration and operation of the water supply adjusting valve constituting the first embodiment of the reactor containment vessel cooling system of the present invention will be described with reference to FIGS.
2 and 3 are diagrams showing the configuration and opening / closing operation of the water supply adjustment valve, FIG. 2 is a view showing the open state of the water supply adjustment valve, and FIG. 3 is a view showing the closed state of the water supply adjustment valve. 2 and 3, the arrows indicate the direction of rotation of the valve drive mechanism 23. 2 and 3, the same reference numerals as those shown in FIG. 1 denote the same parts, and detailed description thereof will be omitted.

  2 and 3, the water supply adjustment valve 20 is a float valve that opens and closes according to the water level of the outer peripheral pool 12. For example, a float 21 that moves up and down according to the water level of the outer peripheral pool 12, and a rod 22 on the float 21. And a valve drive mechanism 23 that rotates according to the vertical movement of the float 21 and a valve body (not shown) that is driven by the valve drive mechanism 23 to open and close the connection pipe 16. ing. The water supply adjustment valve 20 is provided at the end of the connecting pipe 16 disposed in the outer peripheral pool 12.

  As shown in FIG. 2, when the water level of the outer peripheral pool 12 decreases and becomes lower than the set value H, the water supply adjustment valve 20 moves the float 21 accordingly. The valve drive mechanism 23 is rotated in one direction (arrow direction) through the rod 22 by the downward position change of the float 21 to open the valve body.

  On the other hand, when the water level that was less than the set value H rises, the float 21 rises accordingly, as shown in FIG. As the float 21 moves upward, the valve drive mechanism 23 rotates in the direction opposite to the one direction (arrow direction) via the rod 22 and operates in the direction in which the valve element closes. The water supply adjustment valve 20 has the float 21 of the float 21, the length of the rod 22, the rotation angle of the valve drive mechanism 23, etc. so that the connection pipe 16 is completely closed when the water level of the outer peripheral pool 12 becomes a set value H or more. It has been adjusted.

  In this way, the water supply adjustment valve 20 operates only with the static buoyancy of the float 21 and limits the water level of the outer peripheral pool 12 to the set value H. That is, the water supply adjustment valve 20 does not require any power supply and can adjust the water supply amount to the outer peripheral pool 12 without dynamic equipment.

Next, the operation of the first embodiment of the reactor containment vessel cooling system of the present invention will be described with reference to FIGS.
When the reactor pressure vessel 2 and the piping shown in FIG. 1 are damaged and a coolant loss accident occurs in which steam is discharged into the dry well 4, the pressure in the dry well 4 increases. At this time, the released steam is led to the pool water of the suppression pool 6 through the vent pipe 8 and condensed, and the heat of the steam moves to the suppression pool 6. For this reason, the pressure rise in the reactor containment vessel 3 is suppressed.

  Further, when the pressure in the reactor pressure vessel 2 rises above a certain value, a main steam relief safety valve (not shown) is opened. As a result, the steam in the reactor pressure vessel 2 is introduced into the pool water of the suppression pool 6 and condensed, and the heat of the steam moves to the suppression pool 6. For this reason, the pressure rise in the reactor pressure vessel 2 and the reactor containment vessel 3 is suppressed.

  Thus, in the case of a coolant loss accident or an excessive pressure rise in the reactor pressure vessel 2, the heat of the steam in the dry well 4 or the reactor pressure vessel 2 moves to the suppression pool 6. The water temperature of the suppression pool 6 rises due to the heat transferred from the steam, but if the pool water boils and evaporates, the temperature and pressure in the reactor containment vessel 3 will eventually rise. It is necessary to remove the heat.

  When the residual heat removal system operates, the pool water of the suppression pool 6 is sent to a heat exchanger (not shown) outside the reactor containment vessel 3 by a pump (not shown), and the heat of the suppression pool 6 is transferred. It is removed outside the reactor containment vessel 3 system. Thereby, the rise of the temperature and pressure of the reactor containment vessel 3 is prevented.

  On the other hand, when a situation occurs in which the residual heat removal system does not operate, the water temperature of the suppression pool 6 increases. In the present embodiment, the cooling system for the reactor containment vessel 3 operates. That is, the heat of the pool water of the suppression pool 6 whose temperature has risen is transferred to the cooling water of the low temperature outer peripheral pool 12 through the wall surface of the reactor containment vessel 3 and removed outside the reactor containment vessel 3. Thus, the pool water of the suppression pool 6 is statically cooled without a dynamic device such as a pump, and the temperature and pressure of the reactor containment vessel 3 are prevented from rising.

  Assuming a case where the residual heat removal system cannot be operated due to loss of all AC power, etc., it is necessary to cool the suppression pool 6 (reactor containment vessel 3) for a long period of time. In this case, the cooling water in the outer peripheral pool 12 is gradually heated and boiled by heat transfer from the suppression pool 6, and the evaporated vapor is discharged from the discharge hole 13 to the outside of the biological shielding wall 11. When the cooling water is not evaporated, the cooling function of the outer peripheral pool 12 is substantially stopped, but in the present embodiment, the cooling water of the outer peripheral pool 12 is evaporated as shown in FIG. When the water level falls below the set value H, the water supply adjustment valve 20 is automatically opened, and water supply from the makeup water tank 15 shown in FIG. Since the initial position of the water surface T of the make-up water tank 15 is higher than the initial position (set value H) of the water surface P of the outer peripheral pool 12, the make-up water tank 15 without any dynamic equipment and power supply for driving it. Water is supplied by its own weight.

  Conversely, as shown in FIG. 3, when the water level rises to a set value H or more due to water supply, the water supply adjustment valve 20 is automatically closed and water supply is stopped. For this reason, the water level of the outer peripheral pool 12 does not become excessively higher than the set value H, and pressurization to the reactor containment vessel 3 caused by the water head difference between the suppression pool 6 and the outer peripheral pool 12 can be suppressed.

  As described above, the water supply adjustment valve 20 is automatically opened or closed according to the water level of the outer peripheral pool 12 without supplying power, so that the reactor containment vessel 3 is required to be cooled for a long time due to loss of all AC power. Even when a situation occurs, water supply to the outer peripheral pool 12 can be continued statically, and pressurization to the reactor containment vessel 3 can be suppressed.

  If the water supply adjustment valve 20 is stuck in an opened state, water is supplied to the outer peripheral pool 12 until the water levels of the makeup water tank 15 and the outer peripheral pool 12 become equal due to gravity. However, since the discharge hole 13 is provided at a predetermined height position of the biological shielding wall 11, the water level of the outer peripheral pool 12 is reliably prevented from rising above the predetermined height. For this reason, the excessive pressurization to the reactor containment vessel 3 caused by the water head difference between the suppression pool 6 and the outer peripheral pool 12 can be reliably prevented.

  Moreover, when the middle part between the outer periphery pool 12 in the connection pipe 16 and the makeup water tank 15 in the connection pipe 16 breaks due to an earthquake or the like, in the present embodiment, the connection in which the water supply adjustment valve 20 is arranged in the outer periphery pool 12 Since it is provided at the end of the pipe 16, as long as the water supply adjustment valve 20 closes the connection pipe 16, the outflow of the cooling water of the outer peripheral pool 12 from the broken portion can be prevented. For this reason, it is not necessary to connect the connection pipe 16 to the upper part of the outer peripheral pool 12 in consideration of the outflow of the cooling water of the outer peripheral pool 12 due to the breakage of the connection pipe 16. That is, the connecting pipe 16 can be connected to the lower end of the outer peripheral pool 12, and more cooling water in the makeup water tank 15 can be supplied to the outer peripheral pool 12 than when connected to the upper part of the outer peripheral pool 12. Furthermore, a check valve for preventing the cooling water from flowing out of the outer peripheral pool 12 due to the breaking of the connecting pipe 16 is not necessary.

  Further, in the present embodiment, since the makeup water tank 15 for supplying water to the outer peripheral pool 12 is installed outside the living body shielding wall 11, the enlargement of the outer peripheral pool 12 itself is avoided. Cooling water boils faster than a large peripheral pool. For this reason, the outer periphery pool 12 can utilize the boiling heat transfer which can remove heat more efficiently than the convective heat transfer of the cooling water before reaching the boiling point, and can increase the cooling capacity than the large-sized outer periphery pool.

  By the way, unlike this embodiment, when the make-up water tank 15 and the outer peripheral pool 12 are made to communicate without providing the water supply adjustment valve 20, water supply by gravity is possible, but the make-up water tank 15 and the outer pool 12 The water level will be equal. In this case, since it is necessary to limit the water level of the outer peripheral pool 12 from the viewpoint of preventing excessive pressurization to the reactor containment vessel 3 caused by the water head difference between the suppression pool 6 and the outer peripheral pool 12, the makeup water tank 15 The water level is limited accordingly. Therefore, in order to increase the capacity of the makeup water tank 15, the height of the makeup water tank 15 cannot be increased, and the floor area needs to be increased. For this reason, the freedom degree of the installation place in the nuclear power plant of the makeup water tank 15 falls.

  In contrast, in the present embodiment, since the water supply adjustment valve 20 that can adjust the amount of water supplied to the outer peripheral pool 12 according to the water level of the outer peripheral pool 12 is provided in the connection pipe 16, The initial position of the water surface T can be set to an arbitrary position higher than the initial position of the water surface P of the outer peripheral pool 12. Therefore, the capacity of the makeup water tank 15 can be increased by increasing the height and / or floor area of the makeup water tank 15. That is, in the present embodiment, the cooling duration of the reactor containment vessel 3 by the outer peripheral pool 12 can be increased, and the shape of the makeup water tank 15 and the arrangement in the nuclear power plant can be optimized. .

  As mentioned above, according to the first embodiment of the reactor containment vessel cooling system of the present invention, a makeup water tank installed outside the wall surface (biological shielding wall 11) as a part of the reactor building 15, water is supplied to the outer peripheral pool 12 by gravity, and the amount of water supplied to the outer peripheral pool 12 is adjusted by the water supply adjustment valve 20 according to the water level of the outer peripheral pool 12, so that the nuclear reactor containing the outer peripheral pool 12 and the reactor containment vessel 3 The reactor containment vessel 3 can be statically cooled for a long time without increasing the size of the building, and pressurization to the reactor containment vessel 3 can be suppressed. As a result, the safety of the nuclear power plant is improved.

  Further, according to the present embodiment, since the water supply adjustment valve 20 is a float valve that opens and closes according to the water level of the outer peripheral pool 12, even when the loss of all AC power occurs or the like, static electricity is generated by buoyancy without power supply. The water supply regulating valve 20 that operates at the same time can continue water supply to the outer peripheral pool 12 and can suppress pressurization to the reactor containment vessel 3.

[Second Embodiment]
Next, a second embodiment of the reactor containment cooling system of the present invention will be described with reference to FIG.
FIG. 4 is a schematic configuration diagram showing a second embodiment of the reactor containment vessel cooling system of the present invention. In FIG. 4, the same reference numerals as those shown in FIGS. 1 to 3 are the same parts, and detailed description thereof is omitted.

  The second embodiment of the reactor containment vessel cooling system of the present invention shown in FIG. 4 is a float valve in which the water supply adjustment valve 20 constituting the first embodiment opens and closes according to the water level of the outer peripheral pool 12. In contrast, the water supply adjustment valve 40 is an electric valve that is controlled to open and close based on the water level of the outer peripheral pool 12.

  Specifically, a water level meter 41 that measures the water level of the outer peripheral pool 12 is installed in the outer peripheral pool 12. The water level meter 41 is connected to a water supply adjustment valve 40 whose opening and closing is controlled based on the water level measured by the water level meter 41. The water supply adjustment valve 40 is provided at the end of the connection pipe 16 disposed in the outer peripheral pool 12. The water level meter 41 and the water supply adjustment valve 40 are driven by a battery (not shown) and are operable even when all AC power is lost. Also in the present embodiment, water supply to the outer peripheral pool 12 is performed by opening the water supply adjustment valve 40 without using dynamic equipment such as a pump and by the weight of the cooling water in the makeup water tank 15.

  According to the second embodiment of the reactor containment vessel cooling system of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

  Moreover, according to this Embodiment, since the water supply adjustment valve 40 is opened and closed based on the water level measured by the water level gauge 41, the amount of water supplied to the outer peripheral pool 12 can be finely adjusted according to the water level of the outer peripheral pool 12. Can do. As a result, both suppression of pressurization to the reactor containment vessel 3 due to a water head difference between the outer peripheral pool 12 and the suppression pool 6 and an increase in the contact heat transfer area (heat removal amount) can be accurately performed.

[Third Embodiment]
Next, a third embodiment of the reactor containment vessel cooling system of the present invention will be described with reference to FIG.
FIG. 5 is a schematic configuration diagram showing a third embodiment of the reactor containment vessel cooling system of the present invention. In FIG. 5, the same reference numerals as those shown in FIGS. 1 to 4 are the same parts, and detailed description thereof is omitted.

  In the third embodiment of the reactor containment vessel cooling system of the present invention shown in FIG. 5, the makeup water tank 15 constituting the first embodiment is arranged on the same plane as the outer peripheral pool 12. On the other hand, the makeup water tank 55 is disposed higher than the installation surface of the outer peripheral pool 12 in the site of the nuclear power plant. One end of a connecting pipe 56 that connects the outer peripheral pool 12 and the makeup water tank 55 is connected to the bottom surface of the makeup water tank 55 disposed at a high place.

  According to the third embodiment of the reactor containment vessel cooling system of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

  In addition, according to the present embodiment, the makeup water tank 55 is disposed higher than the installation surface of the outer peripheral pool 12 in the site of the nuclear power plant, so that the case where a tsunami or the like enters the site is also affected. It becomes difficult.

  Furthermore, since the connection pipe 56 is connected to the bottom surface of the makeup water tank 55 arranged at a high place, the entire amount of cooling water in the makeup water tank 55 can be supplied to the outer peripheral pool 12. As a result, the cooling of the reactor containment vessel 3 by the outer peripheral pool 12 can be continued for a longer period of time.

[Fourth Embodiment]
Next, a fourth embodiment of the reactor containment vessel cooling system of the present invention will be described with reference to FIG.
FIG. 6 is a schematic configuration diagram showing a fourth embodiment of the reactor containment vessel cooling system of the present invention. In FIG. 6, the arrows indicate the flow direction of the coolant to be replenished. In FIG. 6, the same reference numerals as those shown in FIGS. 1 to 5 are the same parts, and detailed description thereof is omitted.

  The fourth embodiment of the reactor containment vessel cooling system of the present invention shown in FIG. 6 uses an additional replenishing device 67 in place of the replenishing water tank 55 constituting the third embodiment. Is a replenishment water tank 65 having a structure that can be replenished from the outside.

  As the replenishing device 67, for example, it is assumed that a fire truck is used. In this case, the makeup water tank 65 is provided with a connection plug (not shown) that can be connected to the fire hose. Thereby, cooling water can be replenished in the replenishing water tank 65 from an external water source. Further, the makeup water tank 65 may have a structure capable of supplying water by discharging a fire engine.

  In addition, the makeup water tank 65 is installed in a place where humans can easily access it. As a result, the replenishing device 67 such as a fire truck can be easily brought into the vicinity of the replenishing water tank 65. For this reason, water supply work can be easily performed using the replenishing device 67 rather than supplying water directly to the outer peripheral pool 12.

  According to the fourth embodiment of the reactor containment vessel cooling system of the present invention described above, the same effects as those of the third embodiment described above can be obtained.

  Further, according to the present embodiment, the makeup water tank 65 has a structure in which the cooling water can be replenished from the outside using the replenishing device 67, so that the water supply to the outer peripheral pool 12 can be continued for a longer period. As a result, the cooling of the reactor containment vessel 3 can be continued for a longer period.

[Others]
In addition, in this Embodiment mentioned above, the example applied to the nuclear power plant of the boiling water reactor provided with the pressure suppression type steel reactor containment vessel which has a suppression pool was demonstrated. However, the reactor containment vessel cooling system of the present invention can be applied to both boiling water and pressurized water reactors. Moreover, it is applicable also to a nuclear reactor provided with other types of reactor containment vessels.

  For example, even when a suppression pool is not installed in the reactor containment vessel, heat is transferred to the outer pool through the wall of the reactor containment vessel that has become hot due to the convection of steam in the reactor containment vessel. As long as the water supply to the outer pool continues, the reactor containment vessel can be cooled for a long time.

  Also, even if the reactor containment vessel is made of concrete, the thermal conductivity is lower than that of steel and the heat removal efficiency is reduced, but as long as the water supply to the outer peripheral pool continues, the reactor containment vessel can be cooled for a long time It is.

  In the second embodiment of the reactor containment vessel cooling system of the present invention described above, an example in which an electric valve is used as the water supply adjustment valve 40 (see FIG. 5) is shown. It is also possible to use valves with different driving sources. For example, a water supply adjustment valve is driven by air by installing an air cylinder. Even in this case, since the water supply adjustment valve can be opened and closed based on the water level measured by the water level gauge 41, the same effect as in the second embodiment can be obtained.

  Further, the present invention is not limited to the first to fourth embodiments described above, and includes various modifications. The above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. For example, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace another configuration for a part of the configuration of each embodiment.

1 Core 2 Reactor Pressure Vessel 3 Reactor Containment Vessel 11 Biological Shielding Wall (Wall)
12 outer peripheral pool 13 discharge holes 15, 55, 65 makeup water tank 16, 56 connection pipe 20, 40 water supply adjustment valve 41 water level gauge

Claims (9)

A reactor containment vessel cooling system for storing a reactor pressure vessel containing a reactor core,
An outer peripheral pool for storing cooling water in a space between a wall surface portion provided on the outer peripheral side of the reactor containment vessel via a space and the reactor containment vessel;
A replenishment water tank installed outside the wall portion and supplying water to the outer peripheral pool;
A connecting pipe communicating the outer peripheral pool and the makeup water tank;
A reactor containment vessel cooling system, comprising: a water supply adjustment valve that is provided in the connection pipe and adjusts a water supply amount from the makeup water tank to the outer peripheral pool according to a water level of the outer peripheral pool. The reactor containment vessel cooling system according to claim 1,
The reactor containment vessel cooling system, wherein the water supply regulating valve is provided at an end of the connection pipe disposed in the outer peripheral pool. The reactor containment vessel cooling system according to claim 2,
The reactor containment vessel cooling system, wherein the water supply adjustment valve is a float valve that opens and closes according to the water level of the outer peripheral pool. The reactor containment vessel cooling system according to claim 2,
A water level meter installed in the outer peripheral pool and measuring the water level of the outer peripheral pool;
The reactor containment vessel cooling system, wherein the water supply adjustment valve is a valve that is controlled to open and close based on a water level measured by the water level gauge. The reactor containment vessel cooling system according to claim 4,
The water supply regulating valve is an electric valve that can be driven by a battery. The reactor containment vessel cooling system according to claim 4,
The water supply regulating valve is a valve that can be driven by air. The reactor containment vessel cooling system according to any one of claims 1 to 6,
A reactor containment vessel cooling system, wherein a discharge hole capable of discharging the cooling water of the outer peripheral pool is provided at a predetermined height position in the wall surface portion. The reactor containment vessel cooling system according to any one of claims 1 to 6,
The makeup water tank is arranged at a higher position than the outer peripheral pool,
The reactor containment vessel cooling system, wherein the connecting pipe is connected to a bottom surface of the makeup water tank. The reactor containment vessel cooling system according to any one of claims 1 to 6,
The reactor containment vessel cooling system, wherein the makeup water tank can be replenished with cooling water from the outside.

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