JP2000019285A - Reactor heat removal system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor heat removal system with good aseismic performance and obtainable decay heat removable without continuous operation of an auxiliary component cooling system and decay heat removal pump. SOLUTION: A heat exchanger 6 is placed at a position higher than a suppression pool water surface 5a and lines 31, 33 and 34 from a reactor containment 2 to the heat exchanger primary side uppers part are provided. A circulation loop is formed out of these lines, lines from the heat exchanger 6 primary side lower part through a turbine-driven pump 7a to the reactor pressure vessel 1 and the line 37 leading to the suppression pool 5b. Furthermore, an air discharge line with remote valve 18 releasing to the air and a supply line 36 to the secondary side of the heat exchanger 6 are provided to the secondary side of the heat exchanger 6 in the constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for a nuclear reactor that operates when a reactor is abnormal, and more particularly, to a nuclear reactor cooling system in which a final heat removal path is the atmosphere.

[0002]

2. Description of the Related Art As a prior art for a heat removal system for a nuclear reactor, there is a "static containment vessel cooling system" disclosed in Japanese Patent Application Laid-Open No. 6-222182.
The technology disclosed in Japanese Patent Application Laid-Open No. 7-72280, "Reactor Containment Vessel Cooling System" and the technology disclosed in Japanese Patent Application Laid-Open No. 8-201559, "Reactor Containment Vessel Cooling System" .

The technique disclosed in Japanese Patent Application Laid-Open No. 6-222182 relates to a technique for improving the performance of a heat exchanger of a static containment heat removal system. Although the performance of the heat exchanger can be improved, the technique disclosed in Since a static containment heat-removal pool containing a heat exchanger, a gravity-fall type cooling system pool, and a suppression chamber are installed, advanced technology is required for seismic design.

In the technology disclosed in Japanese Patent Application Laid-Open No. 7-72280, although the heat capacity of the containment vessel is increased by using a large heat capacity material, the heat removal performance is improved. Since the equipment configuration is similar to that of the technology disclosed in Japanese Patent No. 222182, advanced technology is required for seismic design.

Further, the technique disclosed in Japanese Patent Application Laid-Open No. Hei 8-201559 is a technique that focuses on removing the obstacle in the seismic design by lowering the position of the static containment cooling pool. Here, an example of a conventional technique disclosed in Japanese Patent Laid-Open Publication No. 8-201559 will be described with reference to FIG.

The reactor containment vessel cooling system includes a reactor containment vessel 2 containing a reactor pressure vessel 1, a core cooling pump 81 using the suppression pool liquid phase part 5b as a water source, and heat around the suppression pool liquid phase part 5b. The cooling water pool 83 accommodates the exchanger 82, the steam supply pipe 84 connecting the dry well 3 and the heat exchanger 82, the exhaust pipe 85, and the condensed water return pipe 86. Further, the heat exchanger 82 is installed above the suppression pool water surface 5 a having the suppression pool gas phase 4.

For example, when an abnormal event occurs in the reactor containment vessel 2, the core cooling pump 81 is operated to inject the water of the suppression pool liquid phase portion 5b into the reactor pressure vessel 1 to cool the core. . Further, the steam in the dry well 3 is sucked by the heat exchanger 82 in the cooling water pool 83, cooled and condensed, and then flows down to the suppression pool liquid phase portion 5b by gravity, thereby cooling the suppression pool water and cooling the reactor. The pressure vessel 1 and the reactor containment vessel 2 can be cooled.

Further, since the cooling water pool 83 is installed at a low position, the center of gravity of the reactor containment vessel 2 is lowered, the earthquake resistance is improved, and a fuel pool is provided above the reactor pressure vessel 1. Plant layout can be performed properly.

[0009] However, this conventional technique is not applicable to the cooling water pool 8.
Since the fuel cell 3 is disposed around the containment vessel 2, the layout of the plant around the containment vessel 2 becomes difficult, and the equipment cost becomes excessive. In addition, although the earthquake resistance is improved by installing the cooling water pool 83 at a low position, since the cooling water pool 83 needs to be arranged at a level higher than the suppression pool water surface 5a, there still remains a problem in the earthquake resistant design. Was.

In the prior art, the cooling water pool 8
A method for coping with the cooling water decrease of No. 3 has not been studied.
For this reason, the concept of the static containment heat removal system including the cooling water supply facility of the cooling water pool 83 has not been clarified.

Further, in the prior art, when an event such as a loss of all AC power occurs, the core cooling pump cannot be used, and there is no method for continuing the long-term injection of water into the reactor.

[0012]

The prior art disclosed in Japanese Patent Application Laid-Open Nos. 6-222182 and 7-72280 disclose a method of removing a containment vessel by installing a static containment heat removal pool above the containment vessel. However, it is necessary to install a static containment heat removal pool and a gravity fall type cooling system pool above the reactor pressure vessel and the containment vessel, which is an obstacle to seismic design. Was.

In the prior art disclosed in Japanese Patent Application Laid-Open No. Hei 8-201559, the seismic performance is improved by installing the cooling water pool at a low position, but there remains a problem in the seismic design. . In addition, in order to improve the seismic performance, water injection into the reactor relied on a core cooling pump, and there was a problem that long-term water injection into the reactor was not possible in the event of a loss of all AC power.

Further, in the above-mentioned conventional technology, as the reactor power increases, the volumes of the cooling water pool and the static containment heat removal pool required for removing the decay heat also increase. There is an increase in costs.

Further, in the conventional reactor heat removal system, continuous operation of equipment including not only the reactor heat removal system but also the auxiliary equipment cooling system is indispensable for final heat removal, and high reliability and advanced In addition to simple maintenance and management, multiplicity that assumes equipment failure was required.

In contrast to the above prior art, a route other than seawater via a static heat removal storage vessel heat removal pool or an auxiliary cooling system is provided as a final heat removal route, thereby making the heat removal route redundant. While maintaining reliability and versatility, increase the equipment costs required for static containment heat removal pools, consider seismic design, and significantly increase the high reliability and advanced maintenance and management required for auxiliary cooling systems It is expected to reduce.

In view of the above problems, an object of the present invention is to provide a reactor heat removal system capable of removing decay heat without continuous operation of an auxiliary equipment cooling system or a residual heat removal pump and having excellent earthquake resistance. Is to do.

[0018]

In order to achieve the above object, a reactor heat removal system according to the present invention has the features described in each of the claims. In particular, the reactor heat removal system of the invention according to claim 1 as an independent claim cools and condenses steam generated in the reactor pressure vessel via a heat exchanger and returns the steam to the reactor pressure vessel. In a reactor heat removal system for removing decay heat, a line with an isolation valve extending from a vapor phase part in the reactor pressure vessel to an upper part on the primary side of the heat exchanger and injection from a lower part on the primary side of the heat exchanger. A circulation loop formed by a line leading to the reactor pressure vessel via a valve, and a turbine drive pump using a steam extracted from the steam phase portion of the reactor pressure vessel disposed in the circulation loop as a drive source, An air release line with an isolation valve that opens to the atmosphere from the secondary side of the heat exchanger, a makeup water line that reaches the secondary side of the heat exchanger, and a reactor containment vessel that houses the reactor pressure vessel. Installed higher than the reactor pressure vessel And pool, and the isolation valve with lines leading to the pool from the outlet of the turbine driven pump, is characterized in that and a isolation valve with lines leading to the reactor pressure vessel from the pool.

[0019]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. In the reactor heat removal system of the present invention, the steam generated in the reactor pressure vessel 1 is supplied to the main steam isolation valve 11a, 1
It is led to the upper part of the heat exchanger 6 via 1b. Heat exchanger 6
Is connected to the injection valve 15 and the check valve 16 via the turbine drive pump 7a.

At this time, the isolation valves 13 and 14 of the lines 33 and 34 connected from the dry well 3 and the suppression pool gas phase section 4 to the upper part of the heat exchanger 6 are closed, and the vapor phase of the reactor pressure vessel 1 is closed. A circulation loop is formed from the upper part of the heat exchanger 6 to the liquid phase part of the reactor pressure vessel 1 from the lower part of the heat exchanger 6.

Although the primary side of the heat exchanger 6 connected to the reactor pressure vessel 1 is depressurized by the pressure regulating valve 21, the tube side of the heat exchanger 6 corresponds to the high pressure condition. The reason for this is that there is no technical problem even if the primary side is the trunk side of the heat exchanger 6, but the production cost is high because the entire trunk is of high-pressure specification.

On the other hand, cooling water is contained on the secondary side of the heat exchanger 6, and a line 35 for opening to the atmosphere via an atmosphere opening valve 18 is provided above the cooling water. With these configurations, the steam generated in the reactor pressure vessel 1
Heat is transferred from the primary side of the heat exchanger 6 to the cooling water on the secondary side,
Condense.

The steam condensed in the upper part of the heat exchanger 6 is pressurized from the lower part of the heat exchanger 6 by a turbine drive pump 7a driven by steam through a steam supply line 38 from the reactor pressure vessel 1. Return to the reactor pressure vessel 1.

When heat removal from the dry well 3 is performed, each of the lines 3 connected to the upper part of the heat exchanger 6 from the reactor pressure vessel 1 and the suppression pool gas phase part 4 is used.
The isolation valves 12 and 14 of 1 and 34 are closed, the isolation valve 13 of a line 33 is opened, and an injection valve is provided from the drywell 3 to the upper part of the heat exchanger 6 and from the lower part of the heat exchanger 6 via a line 37. 17 is opened and the suppression pool liquid phase 5
Form a circulation loop to b. However, the heat exchanger 6 is provided at a position higher than the suppression pool water surface 5a.

With the above configuration, the steam in the dry well 3 transfers heat from the primary side of the heat exchanger 6 to the cooling water on the secondary side and condenses. The vapor condensed in the upper part of the heat exchanger 6 flows into the suppression pool liquid phase part 5b from the lower part of the heat exchanger 6 according to gravity.

When heat is to be removed from the suppression pool gas phase section 4, each of the lines 3 connected from the reactor pressure vessel 1 and the dry well 3 to the upper part of the heat exchanger 6
The isolation valves 12 and 13 of 1 and 33 are closed, and the isolation valve 14 of a line 34 is opened. From the suppression pool gas phase part 4, from the upper part of the heat exchanger 6 and from the lower part of the heat exchanger 6, via a line 37. Then, the injection valve 17 is opened, and a circulation loop to the suppression pool liquid phase portion 5b is formed.

With these configurations, the steam of the suppression pool gas phase section 4 transfers heat from the primary side of the heat exchanger 6 to the cooling water on the secondary side and condenses. The vapor condensed in the upper part of the heat exchanger 6 flows into the suppression pool liquid phase part 5b from the lower part of the heat exchanger 6 according to gravity.

The cooling water on the secondary side of the heat exchanger 6 obtains heat from the primary side, evaporates, and is released to the atmosphere through an atmosphere opening valve 18. When the cooling water on the secondary side of the heat exchanger 6 decreases due to the evaporation, the supply water valve 19 is opened to supply the cooling water. In addition, the makeup water line 36 on the secondary side of the heat exchanger
The replenishing water tank 8 is provided at a position higher than the heat exchanger 6, and the replenishing water valve 20 is opened to supply the cooling water by gravity. However, make-up water tank 8
Is installed in an area different from the reactor containment vessel 2.

When water is not injected into the reactor pressure vessel 1, the injection valve 15 is closed and the isolation valve 25 is opened, whereby water can be injected into the pool 9 from the turbine drive pump 7a. When the turbine drive pump 7a is used, steam generated in the reactor pressure vessel 1 is eventually lost, and the turbine drive pump 7a cannot be used.

On the other hand, the water stored in the pool 9 is released from the reactor pressure vessel 1 by opening the isolation valve 24.
To supply water to the reactor pressure vessel 1 for a long period of time. The water source of the pool 9 includes not only the water condensed in the heat exchanger 6 but also the isolation valve 2 in the line 37.
7 to open the makeup water tank 8 and the line 44
By opening the isolation valve 26, the suppression pool liquid phase portion 5b can be used.

As a result, long-term safety can be ensured even when the steam generated in the reactor pressure vessel 1, which is the drive source of the turbine drive pump 7a, is lost. If intermittent make-up water to the secondary side of the heat exchanger 6 is obtained, long-term cooling of the reactor and removal of decay heat with low power can be ensured only by the lineup of valves.

A second embodiment of the present invention will be described with reference to FIG. The circulation loop on the primary side of the heat exchanger 6 and the water injection line from the suppression pool liquid phase portion 5b to the pool 9 by the turbine drive pump 7a have the same configuration as in FIG.

FIG. 2 shows a turbine drive pump 7b in a makeup water line 36 from a makeup water tank 8 to the secondary side of the heat exchanger 6 provided in FIG. 1, and a reactor pressure vessel 1 in the turbine drive pump 7b. A steam supply line 39 is provided. Thus, the pressure of the makeup water in the makeup water tank 8 can be increased by the turbine drive pump 7 b and can be supplied to the secondary side of the heat exchanger 6.

A line 46 connected from the turbine drive pump 7b to the pool 9 opens the isolation valve 28 when water is not supplied to the secondary side of the heat exchanger 6, and opens the isolation valve 8
7 is closed, the makeup water tank 8 is moved to the pool 9
, And a water source for water injection into the reactor pressure vessel 1 can be secured. With this configuration, long-term reactor cooling and decay heat removal with low power can be ensured with only a lineup of valves without limiting the arrangement of the makeup water tank 8.

A third embodiment of the present invention will be described with reference to FIG. The circulation loop on the primary side of the heat exchanger 6 and the water injection line from the suppression pool liquid phase portion 5b to the pool 9 by the turbine drive pump 7a have the same configuration as in FIG.

FIG. 3 shows a line 40 and an isolation valve 88 from the makeup water line 36 to the secondary side of the heat exchanger 6 provided in FIG. 1 to the turbine drive pump 7a, and the turbine drive pump 7a.
A line 41 with an isolation valve 23 connected to a make-up water line 36 from a downstream side of the heat exchanger 6 to the secondary side of the heat exchanger 6, and a make-up water line 3
6 is provided with an isolation valve 22.

Thus, the pressure of the makeup water in the makeup water tank 8 can be increased by the turbine drive pump 7a and can be supplied to the secondary side of the heat exchanger 6 through the line 41. With this configuration, the number of pumps can be reduced, and the removal of decay heat with low power can be ensured only by the lineup of valves.

The valve of the present invention is desirably provided with the following interlock.

(1) When the isolation valve 12 is opened, the injection valve 17 in the suppression pool return line 37, the isolation valve 13 in the line 33 connected from the dry well 3 to the upper part of the heat exchanger 6, and the suppression pool gas phase 4 The isolation valve 14 of the line 34 connected to the upper part of the heat exchanger 6 is closed.

(2) When the isolation valve 13 is opened, the isolation valve 12 and the isolation valve 14 of the line 34 connected from the suppression pool gas phase 4 to the upper part of the heat exchanger 6 are closed.

(3) When the isolation valve 14 is opened, the isolation valve 13 of the line 33 connected from the dry well 3 to the upper part of the heat exchanger 6 is closed.

(4) When the isolation valve 15 is opened, a line 43 connected from the turbine drive pump 7a to the pool 9
That the isolation valve 25 is closed.

(5) When the isolation valve 87 is opened, the line 46 connected from the turbine drive pump 7b to the pool 9
Isolation valve 28 is closed.

An example of the control logic of the present invention will be described with reference to FIG. FIG. 4 shows the dry well pressure high signal (D /
Abbreviated as W pressure height) 50, reactor water level high signal 51,
A suppression pool pressure high signal (abbreviated as S / C pressure high) 52, a differential pressure positive signal 53 obtained by subtracting the suppression pool pressure from the drywell pressure, a switch 54, and the drywell 3 via the heat exchanger 6. A signal 55 for permitting formation of a circulation loop to the suppression pool liquid phase portion 5b,
A signal 56 is provided for permitting formation of a circulation loop from the suppression pool 4 to the suppression pool liquid phase portion 5b via the heat exchanger 6.

During the formation of a circulation loop from the reactor pressure vessel 1 to the reactor pressure vessel 1 via the heat exchanger 6, when the reactor water level high 51 is generated and the dry well pressure high signal 50 is generated, When the signal of the switch 54 is generated, a circulation loop formation permission signal 55 is established.

During the formation of a circulation loop from the reactor pressure vessel 1 to the reactor pressure vessel 1 via the heat exchanger 6, a reactor water level high 51 was generated and a suppression pool pressure high signal 52 was generated. In this case, if the signal of the switch 54 is generated, the circulation loop formation permission signal 56 is established.

However, a dry well pressure high signal 50, a reactor water level high signal 51, a suppression pool pressure high signal 5
2 and the switch 54 are all generated, if the positive differential pressure signal 53 is generated, the formation permission signal 55 of the circulation loop is established, but if the positive differential pressure signal 53 is not generated,
A circulation loop formation permission signal 56 is established. With this configuration, a circulation loop is formed from a region where heat removal is most preferable.

FIG. 5 shows an example of a horizontal installation of a U-tube heat exchanger.
2 shows a configuration example of a secondary water level control system of the heat exchanger 6 applied to the first embodiment. The control system sets a water level gauge 70 for measuring the water level of the body of the heat exchanger 6, a signal 71 of the water level gauge, an optional water level setting signal 72, a control signal 73 for the makeup water valves 19 and 20, and the opening and closing of the isolation valve. And a control system 74 that performs the control.

The control logic of the secondary water level control system 74 of the heat exchanger 6 will be described with reference to FIG. The control logic is
To the secondary side of the heat exchanger 6, the secondary water level high signal 57 of the heat exchanger 6, the signal 58 indicating that the water level is higher than a predetermined water level set value, the secondary water level low signal 59 of the heat exchanger 6, And a supply start request signal 61 to the secondary side of the heat exchanger 6.

When the secondary water level high signal 57 of the heat exchanger 6 is generated and the signal 58 indicating that the water level is equal to or higher than the set water level is established, a request to stop supply of heat to the secondary side of the heat exchanger 6 is issued. A signal is generated. When the signal 58 indicating that the water level is equal to or higher than the water level set value is not generated and the secondary water level low signal 59 of the heat exchanger 6 is established, a replenishment start request signal to the heat exchanger 6 is generated. . By controlling the water level on the secondary side of the heat exchanger 6 in this manner, heat can be continuously removed.

FIG. 7 shows an example of the control characteristics of the above control logic. The water level on the secondary side of the heat exchanger 6 is
When the tube bundle rises to the upper end, the heat exchange amount also increases. At a water level below the lower end of the tube bundle of the heat exchanger 6, remarkable heat exchange cannot be expected. Further, the heat exchanger 6
Excessive rise in the water level on the secondary side of the above is undesirable because the cooling water flows out of the heat exchanger 6.

From these facts, the water level change range on the secondary side of the heat exchanger 6 is changed from the upper end of the tube bundle of the heat exchanger 6 to the upper end of the heat exchanger 6 in response to the increase of the water level control signal. Set to keep the upper limit. Further, the lower limit of the water level control signal is set so as to maintain the lower limit from the lower end of the tube bundle of the heat exchanger 6 to the lower end of the heat exchanger 6.

On the primary side of the heat exchanger 6, there are a vapor phase supplied from the reactor pressure vessel 1, the dry well 3, and the suppression pool gas phase 4, and a condensed liquid phase below. On the secondary side, there is an evaporative vapor phase at the top and a cooling water phase at the bottom.

For this reason, when the water level on the secondary side of the heat exchanger 6 is raised, the amount of heat exchange between the primary side steam and the secondary side cooling water increases, and the amount of heat removal can be increased. By controlling the water level on the secondary side of the heat exchanger 6 in this manner, the heat removal amount can be controlled.

[0055]

According to the present invention, as the final heat removal path,
In addition to conventional seawater, heat release to the atmosphere can be expected. As a result, measures to be taken in the event of a plant trouble increase, and improvement in plant safety can be expected. In addition, since the dependence on the auxiliary cooling system is reduced, the high reliability and advanced maintenance and management required for the conventional auxiliary cooling system can be reduced, and the cost of construction and management can be reduced. it can.

Further, heavy equipment such as a cooling pool adjacent to the upper part of the plant can be omitted, excellent in earthquake resistance, plant layout is easy, and construction cost can be reduced. Furthermore, by limiting the dynamic equipment of the reactor heat removal system to line valves and turbine-driven pumps and securing a water source using a turbine-driven pump in the reactor containment vessel, it is possible to continuously operate with low power. Decay heat removal can be achieved. Thereby, the reliability of the decay heat removal function can be improved, and the safety of the plant can be improved.

[Brief description of the drawings]

FIG. 1 is a process flow showing a first embodiment of the present invention.

FIG. 2 is a process flow showing a second embodiment of the present invention.

FIG. 3 is a process flow showing a third embodiment of the present invention.

FIG. 4 is a control logic diagram of an interlock according to the present invention.

FIG. 5 is a diagram of a water level control system of the heat exchanger of the present invention.

FIG. 6 is a water level control logic diagram of the present invention.

FIG. 7 shows a water level control characteristic of the heat exchanger of the present invention.

FIG. 8 is a process flow of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel 2 ... Reactor containment vessel 3 ... Dry well 4 ... Suppression pool gas phase part 5a ... Suppression pool water surface 5b ... Suppression pool liquid phase part 6 ... Heat exchanger 7a, 7b ... Turbine drive pump 8 ... Supply Water tank 9 ... Pool 11a, 11b ... Main steam isolation valve 12 ... Isolation valve 13 ... Isolation valve 14 ... Isolation valve 15 ... Injection valve 16 ... Check valve 17 ... Injection valve 18 Atmospheric release valve 19 ... Refill water valve 20 ... Replenishment Water valve 21 ... Pressure regulating valve 22 ... Isolation valve 23 ... Isolation valve 24 ... Isolation valve 25 ... Isolation valve 26 ... Isolation valve 27 ... Isolation valve 28 ... Isolation valve 31,32,33,34,35,36,37,38 , 3
9, 40, 41, 42, 43, 44, 45, 46... Connected piping lines 50, 51, 52, 53, 54, 55, 56, 57, 5
8, 59, 60, 61 ... control signal 70 ... water level gauge 71 ... water level signal 72 ... arbitrary water level setting signal 73 ... control signal 74 ... control system 81 ... core cooling pump 82 ... heat exchanger 83 ... cooling water pool 84 ... Steam supply pipe 85 ... exhaust pipe 86 ... condensed water return pipe 87 ... isolation valve 88 ... isolation valve

Claims (11)

[Claims] 1. A reactor heat removal system for cooling and condensing steam generated in a reactor pressure vessel via a heat exchanger and removing the decay heat by returning the steam to the reactor pressure vessel, A line with an isolation valve extending from the vapor phase portion in the pressure vessel to the upper part on the primary side of the heat exchanger and a line from the lower part on the primary side of the heat exchanger to the reactor pressure vessel via an injection valve were formed. A circulation loop, a turbine drive pump driven by steam extracted from the vapor phase portion of the reactor pressure vessel disposed in the circulation loop, and an isolation valve opened to the atmosphere from a secondary side of the heat exchanger With an atmospheric release line, a makeup water line leading to the secondary side of the heat exchanger, and a pool installed at a higher position than the reactor pressure vessel in a reactor containment vessel containing the reactor pressure vessel; Outlet of turbine driven pump And with line isolation valve leading to the pool, the reactor heat removal system characterized by comprising, an isolation valve with lines leading to the reactor pressure vessel from the pool. 2. The heat exchanger is installed at a position higher than the water level of a suppression pool, and a line with an isolation valve extending from an upper part of the containment vessel to an upper part on a primary side of the heat exchanger or the suppression pool air. A circulation loop formed by a line with an isolation valve from the phase portion to the upper portion on the primary side of the heat exchanger, and a line from the lower portion on the primary side of the heat exchanger to the suppression pool liquid phase portion via the injection valve. The reactor heat removal system according to claim 1, further comprising: 3. A replenishing water tank provided in the replenishing water line is installed at a position higher than the heat exchanger, and replenishment to the secondary side of the heat exchanger is performed by gravity. The reactor heat removal system according to claim 1 or 2. 4. A make-up water tank provided in the make-up water line, a turbine drive pump using steam extracted from a steam phase portion of the reactor pressure vessel provided in the make-up water line as a drive source, The reactor heat removal system according to claim 1 or 2, further comprising: 5. The heat exchanger according to claim 1, wherein said heat exchanger is provided between said turbine drive pump and an injection valve disposed in a line extending from a lower portion on the primary side of said heat exchanger to said reactor pressure vessel via an injection valve. The reactor heat removal system according to any one of claims 1 to 3, further comprising a line with an isolation valve branched to the next side. 6. A line with an isolation valve extending from the vapor phase portion in the reactor pressure vessel to an upper portion on the primary side of the heat exchanger, and the atom from the lower portion on the primary side of the heat exchanger via an injection valve. A first circulation loop formed by a line leading to a reactor pressure vessel, a line with an isolation valve extending from the upper part of the containment vessel to the upper part of the primary side of the heat exchanger, and a lower part of the primary side of the heat exchanger. A second circulation loop formed by a line leading to the suppression pool liquid phase through an injection valve; a line with an isolation valve from the suppression pool gas phase to an upper portion of the primary side of the heat exchanger; and the heat exchange. A third circulation loop formed by a line extending from the lower portion of the primary side of the reactor to the suppression pool liquid phase through an injection valve, and a third heat removal system having three circulation loops, Le The use of the second circulation loop and the third circulation loop is prevented when using the loop, and the use of the first circulation loop and the third circulation loop is prevented when the second circulation loop is used, 6. The method according to claim 2, wherein an interlock is provided so as to prevent use of the first circulation loop and the second circulation loop when the third circulation loop is used. Reactor heat removal system as described. 7. A control system that compares a reactor water level and a predetermined set value, an upper pressure in the reactor containment vessel and a pressure in the suppression pool gas phase, and enables one of the three circulation loops. The reactor heat removal system according to any one of claims 2 to 6, further comprising: 8. The secondary side of the heat exchanger by comparing the water level on the secondary side of the heat exchanger with a predetermined set value and adjusting the opening of an injection valve disposed in the makeup water line. The reactor heat removal system according to any one of claims 1 to 7, further comprising a control system for keeping the water level constant. 9. A water level change range on the secondary side of the heat exchanger, wherein the upper limit is between the upper end of the tube bundle of the heat exchanger and the upper end of the heat exchanger, and the lower limit is from the lower end of the tube bundle of the heat exchanger. The reactor heat removal system according to claim 8, wherein the restriction is made up to a lower end of the heat exchanger. 10. When the first circulation loop is used, an interlock is provided so that injection of water into the pool by a line with an isolation valve from the outlet of the turbine drive pump to the pool is prevented. The reactor heat removal system according to any one of claims 1 to 9, characterized in that: 11. When water is supplied from the makeup water line to the heat exchanger secondary side, injection of water into the pool by a line with an isolation valve from an outlet of the turbine drive pump to the pool is prevented. The reactor heat removal system according to any one of Claims 4 to 6, further comprising an interlock.