JPH10160884A - Emergency core-cooling system of reactor power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emergency core cooling system of reactor power plant which is combinedly constituted of a system separating the emergency core cooling system of a BWR power station into 3 divisions and injecting cooling water in high pressure and low pressure of the reactor in each division, and a system capable of spray cooling in the reactor containment. SOLUTION: An emergency core cooling system of a reactor power station separates the emergency core cooling system of a BWR in 3 divisions, is provided with high pressure water injection systems 23a and 23b and residual heat removal systems 19a and 19b and with heat exchangers 17 to enable spray cooling in the reactor containment in the first and second divisions, is provided with a reactor core isolation cooling system 21 and a residual heat removal system 19c and a heat exchanger 17 to enable spray cooling in the reactor containment in the third division, and is provided with two systems of automatic depressurization systems 20a and 20b independently of the systems of the three divisions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency core cooling system for a nuclear power plant, in which cooling water is injected into a reactor core to cool the reactor when the reactor shuts down in a boiling water nuclear power plant in an emergency. About the system.

[0002]

2. Description of the Related Art In a conventional boiling water nuclear power plant, for example, a boiling water reactor (hereinafter referred to as BW-5) of a 1.1 million kW class called BWR-5 type.
R). As for the BWR-5, as shown in the schematic diagram of FIG. 3, the reactor pressure vessel 3 in which the reactor core 2 is installed as the reactor 1 is cooled when the reactor is shut down in an emergency. Emergency Core Cooling System (E)
As CCS), facilities for various cooling systems are formed.

First, a high-pressure core spray sparger 4 for spraying cooling water to the core 2 in a spray form is provided above the core 2 in the reactor pressure vessel 3. A high-pressure core spray pump 5 is connected to the sparger 4 to form a high-pressure core spray system 6, and spraying is performed in which the cooling water is sprayed to the core 2 when the pressure in the reactor 1 is high to low when the cooling water is sprayed. I do.

A low-pressure core sparger 7
A low-pressure core spray system 9 formed by connecting a low-pressure core spray pump 8 sprays cooling water onto the core 2 when the pressure inside the reactor 1 is low.

Next, a pump 11 connected to a residual heat removal system is connected to an injection pipe 10 provided above the reactor core 2 in the reactor pressure vessel 3 so that the reactor core 2 is cooled when the reactor pressure is low. Residual Heat Removal System that injects water
em, RHR) 12 are formed.

Further, as shown in the schematic diagram of FIG.
The reactor 1 is housed in a reactor containment vessel 13. Inside the reactor containment vessel 13, cooling water is sprayed in a spray state to cool the inside of the reactor containment vessel 13. The reactor containment sparger 14 is installed.

The containment vessel sparger
14, a pool heat 16 stored in a pressure suppression chamber 15 provided at a lower portion of the reactor containment vessel 13 is sucked up as cooling water, and the residual heat removal system pump 11 of the residual heat removal system 12 is provided with a heat exchanger 17. The reactor containment vessel spray system 18 is formed by connecting the above. The facilities of each system are generally constituted by a plurality of systems in order to improve reliability.

Thus, as shown in the system configuration diagram of FIG. 5, the emergency core cooling system in the BWR-5 is divided into three independent sections of a first section, a second section, and a third section. A water injection system is configured.

Further, each section is physically and electrically separated from each other, and an abnormal event in each section does not affect the function of the cooling water injection system of the other two sections at all. I have. In addition, system facilities in each section
It is mainly composed of equipment such as a pump and piping, and a heat exchanger 17 is provided in some of the special residual heat removal systems.

That is, the first section of the reactor 1 is constituted by a high-pressure core spray system 6, and a relatively small flow rate of cooling water is used when the reactor pressure is high and the reactor pressure is low. At low pressure, a relatively large flow rate of cooling water is sprayed in a spray state by a high pressure core sparger 4 and injected into the core 2.

The second section is composed of a low-pressure core spray system 9 and an A residual heat removal system 19a. The low-pressure core spray system 9 supplies cooling water by the low-pressure core sparger 7 when the pressure in the furnace is low. , Sprayed and injected into the reactor core 2. The A residual heat removal system 19a injects cooling water into the reactor 1 through the injection pipe 10 when the pressure in the reactor is low.

The A residual heat removal system 19a is provided with a heat exchanger 17 and is installed in a reactor containment vessel 13 containing the reactor pressure vessel 3 as the reactor 1.
The reactor has a function of a reactor containment spray system 18 for spraying cooling water into the reactor containment 13 through the reactor containment sparger 14 to spray-cool.

The third section is composed of a B residual heat removal system 19b and a C residual heat removal system 12.
The b and C residual heat removal system 12 is used for the injection pipe 10 when the furnace pressure is low.
To inject the cooling water into the reactor 1. The B residual heat removal system 19b is provided with a heat exchanger 17,
Similar to the residual heat removal system 19a, it has a function of a reactor containment spray system 18 for spray cooling the inside of the containment vessel 13.

As described above, the reason why the emergency core cooling system is divided into three sections is that the emergency core cooling system in all sections is operated when the reactor 1 is stopped in an emergency. This is because, even when a part of the system is defective, the reactor 1 can be safely cooled in other healthy sections without any trouble.

For example, even if the emergency core cooling system pipe in the first section ruptures and a coolant loss accident occurs, and the emergency core cooling system in the second section has a single failure, the third section is also used. Injection of cooling water into the reactor 1 by the B residual heat removal system 19b and the C residual heat removal system 12
The cooling of the reactor 1 can be performed safely without any trouble.

Further, as a part of the emergency core cooling system of the BWR-5, automatic decompression systems 20a and 20b independent of the cooling system of the three sections are provided. , Each of which comprises a plurality of relief safety valves, and is composed of two systems, an A automatic pressure reducing system 20a and a B automatic pressure reducing system 20b.

The automatic pressure-reducing systems 20a and 20b prevent the pressure inside the reactor 1 from excessively increasing in the event of a coolant loss accident due to, for example, a small break in the water supply pipe, thereby ensuring the integrity of the reactor pressure vessel 3. Therefore, it is also a safety facility that discharges high-pressure steam from the reactor pressure vessel 3 to forcibly lower the pressure in the reactor.

The pressure in the furnace is reduced by the operation of the automatic pressure reducing systems 20a and 20b.
In the low pressure core spray system 9, the A residual heat removal system 19a, the B residual heat removal system 19b, and the C residual heat removal system 12, the function of the emergency core cooling system is further improved because the cooling water is easily injected. Easy to demonstrate.

In addition to the above, although not an emergency core cooling system, a reactor isolation cooling system is provided as a facility for cooling the reactor 1 when water supply to the reactor 1 is lost when the reactor is stopped. There are 21. In the reactor isolation cooling system 21, when the pressure of the reactor 1 is high due to, for example, a small break in the water supply pipe, cooling water is injected into the reactor pressure vessel 3 to cool the reactor 1. It also has substantial functions.

However, recently, an advanced boiling water reactor of 1.35 million kW class (Advanced Boiling Water Reactor)
r, hereinafter abbreviated as ABWR) has been constructed. As shown in the system configuration diagram of FIG. 6, the emergency core cooling system in the ABWR is composed of three independent cooling water injection systems and two automatic pressure reducing systems 20a and 20b.

In the first section of the cooling water injection system, AB
A reactor isolation cooling system 21 that can inject cooling water into the reactor 22 when the reactor pressure of the WR reactor 22 is high, and an A residual heat removal system 19a that can inject cooling water into the reactor 22 when the reactor pressure is low. It consists of: The A residual heat removal system 19a includes a heat exchanger 17, and performs spray cooling in the reactor containment vessel 13 through the reactor containment spar sparger 14 in the reactor containment vessel 13. Reactor containment spray system
It has 18 functions.

The second section includes an A high-pressure water injection system 23a capable of injecting cooling water into the reactor 22 when the pressure inside the reactor 22 is high to low, and a cooling water to the reactor 22 when the pressure inside the reactor 22 is low. And a B residual heat removal system 19b that can be injected. Further, the B residual heat removal system 19b has a heat exchanger 17, and has the function of the reactor containment spray system 18 like the A residual heat removal system 19a.

The third section is the same as the second section,
A high-pressure B water injection system 23b that can inject cooling water into the reactor 22 when the pressure inside the reactor 22 is high to low, and a C residual heat removal system 19c that can inject cooling water into the reactor 22 when the pressure inside the furnace is low.
It consists of: The C residual heat removal system 19c has a heat exchanger 17, and has the function of a reactor containment spray system 18 like the A residual heat removal system 19a.

The injection of the cooling water into the reactor 22 by the A high-pressure water injection system 23a and the B high-pressure water injection system 23b has a structure similar to that of the residual heat removal system 12 shown in FIG. The pool water 16 sucked up by the water injection pump and stored in the pressure suppression chamber 15 is injected as cooling water into the reactor 22 through an injection pipe.

[0025]

SUMMARY OF THE INVENTION BWR-5 and ABW
The emergency core cooling system at R is divided into three sections, all of which fulfill the function of ensuring the required reliability and safety when the reactor is shut down. However, BWR
A detailed comparison of the emergency core cooling system of the ABWR-5 and ABWR shows that the ABWR is more reliable and safer than the BWR-5.

That is, in the emergency core cooling system of the BWR-5, as shown in FIG. 5, a system capable of injecting cooling water from a high pressure in the furnace is a high pressure core spray system 6 in the first section.
And a reactor isolation cooling system outside the emergency core cooling system
21 and two systems. In the other second and third sections, the low pressure core spray system 9 and the A residual heat removal system 19a, and the B residual heat removal system 19b and the C residual heat removal system 12
In each case, only a system capable of injecting cooling water at low pressure.

On the other hand, in the ABWR, as shown in FIG. 6, there are three systems in which cooling water can be injected into the reactor 22 when the pressure in the reactor is high, and the first section is a cooling system 2 when the reactor is isolated.
1, high pressure water injection system 23a in the second section, B in the third section
The high-pressure water injection system 23b is distributed to each section.

Also, in a system capable of injecting cooling water into the nuclear reactor 22 at a low pressure, A residual heat removal systems 19a to 19c are respectively allocated to the respective sections. Cooling water is supplied to each section from the reactor pressure when the reactor pressure is high.
A system capable of injecting cooling water at low pressure and a system capable of injecting cooling water at low pressure are both provided.

Further, the reactor containment spray system 18
The BWR-5 also has a residual heat removal system 19a in the second section of the BWR-5, which has a heat exchanger 17 capable of spray cooling the inside of the reactor containment vessel 13 with the function of
There are only two systems, that is, the B residual heat removal system 19b in the third section.
However, in the ABWR, A residual heat removal systems 19a to 19c provided in each of the first to third sections are provided.
In all three systems, the reactor containment spray system
It has 18 functions.

As described above, if a failure occurs in the emergency core cooling system, the emergency core cooling system is cooled by injecting cooling water into the reactor 1 when the reactor pressure is high and low. The conditions under which the function of spray cooling in the reactor containment vessel 13 is reduced are excellent in reliability and safety because ABWR is less.

The purpose of the present invention is to provide a BWR-5
In a nuclear power plant that adopts a system, the emergency core cooling system is divided into three sections, and a cooling water can be injected into the reactor from high pressure into each section, An object of the present invention is to provide an emergency core cooling system for a nuclear power plant in which a system capable of spray cooling is combined to improve the reliability and safety of the emergency core cooling system.

[0032]

According to a first aspect of the present invention, there is provided an emergency core cooling system for a nuclear power plant, comprising: a boiling water reactor; The emergency core cooling system is divided into three sections, and a first section and a second section are each provided with a high-pressure water injection system capable of injecting cooling water into the reactor from high pressure to low pressure in the reactor and a pressure in the reactor. A residual heat removal system capable of injecting cooling water into the reactor at a low pressure, the residual heat removal system includes a heat exchanger to enable spray cooling in the reactor containment vessel, A reactor isolation cooling system that can inject cooling water into the reactor when the internal pressure is high and a residual heat removal system that can inject cooling water into the reactor when the reactor pressure is low are provided. Reactor containment vessel with heat exchanger Spray cooling permits a and characterized by further providing the automatic depressurization system of independent two systems and cooling system of the third section.

At the time of an emergency shutdown of the reactor, cooling is performed by injecting cooling water into the reactor by an emergency core cooling system. At this time, the emergency core cooling system independently divided into three sections is provided. In the first and second sections, cooling water is injected by a high-pressure water injection system when the pressure in the furnace is high to low. In addition, at low pressure, cooling water is injected from the residual heat removal system, and cooling water is sprayed into the reactor containment via the heat exchanger of the residual heat removal system to cool the reactor vessel.

In the third section, cooling water is injected by the reactor isolation cooling system when the pressure in the reactor is high, cooling water is injected from the residual heat removal system when the pressure is low, and the heat of the residual heat removal system is also increased. The inside of the containment vessel is spray-cooled via the exchanger. Since the cooling systems of the first to third sections are all independent, even if a part of the cooling system fails, the reactor is cooled without being affected by the failure.

Further, when the pressure inside the reactor rises excessively, the two automatic pressure reducing systems operate to lower the pressure inside the reactor. Water injection is easy and the cooling function is improved.

The emergency core cooling system for a nuclear power plant according to the invention according to claim 2 is an emergency core cooling system for a nuclear power plant using a boiling water reactor, wherein the emergency core cooling system is divided into three sections. The first section and the second section are divided into a high pressure water injection system capable of injecting cooling water into the reactor from a high pressure to a low pressure in the reactor and a spray water is injected into the upper part of the core at a low pressure in the reactor. In addition to providing a residual heat removal system, the residual heat removal system includes a heat exchanger to enable spray cooling in the reactor containment vessel, and the third section supplies cooling water into the reactor when the reactor pressure is high. A reactor isolation cooling system that can be injected and a residual heat removal system that can inject cooling water into the reactor when the pressure in the reactor is low are provided, and the residual heat removal system includes a heat exchanger and is provided inside the reactor containment vessel. Spray cooling Characterized by providing an automatic depressurization system of independent two systems and cooling system of the third section.

At the time of an emergency shutdown of the nuclear reactor, cooling is performed by injecting cooling water into the reactor by an emergency core cooling system. At this time, the emergency core cooling system divided into three sections independently. In the first and second sections, cooling water is injected by a high-pressure water injection system when the pressure in the furnace is high to low. In addition, at low pressure, cooling water is sprayed from the residual heat removal system and injected, and cooling water is sprayed into the reactor containment vessel through the heat exchanger of the residual heat removal system to be cooled. .

In the third section, when the pressure in the reactor is high, cooling water is injected by the cooling system during isolation of the reactor, and when the pressure is low, cooling water is sprayed from the residual heat removal system and injected. The inside of the reactor containment is spray-cooled via the heat exchanger of the removal system. Since the cooling systems of the first to third sections are all independent, even if a part of the cooling system fails, the reactor is cooled without being affected by the failure.

Further, when the pressure inside the reactor rises excessively, the two automatic pressure reducing systems operate to lower the pressure inside the reactor, so that the cooling water supplied to the reactor by the cooling system of the three compartments is used. Water injection is easy and the cooling function is improved.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described conventional technology are denoted by the same reference numerals, and detailed description is omitted. The first embodiment relates to claim 1, and for a nuclear power plant employing, for example, BWR-5 for the boiling water reactor, as shown in the system configuration diagram of FIG. The reactor core cooling system is composed of three independent cooling water injection systems and two automatic pressure reducing systems 20a and 20b.

The first section is provided with an A high-pressure water injection system 23 capable of injecting cooling water into the reactor 1 when the pressure in the reactor is high to low.
a and a residual heat removal system 19a capable of injecting cooling water into the reactor 1 when the pressure in the reactor is low. The A residual heat removal system 19a includes a heat exchanger 17, and the reactor containment vessel sparger inside the reactor containment vessel 13.
The reactor has a function of a reactor containment spray system 18 for spraying cooling water into the reactor containment 13 in a spray form through the reactor 14 for cooling.

The second section is the same as the first section, and includes a B high-pressure water injection system 23b and a B residual heat removal system 19b having a heat exchanger 17 and functioning as a reactor containment spray system 18. Make up. The third section has the functions of a reactor isolation cooling system 21 that can inject cooling water into the reactor 1 when the pressure inside the reactor is high, and a cooling water spray system 18 that can inject cooling water into the reactor 1 when the pressure is low. A residual heat removal system, comprising:
19a and a C residual heat removal system 19c having the same configuration.

Therefore, in this cooling water injection system, each of the three divided sections is independently divided into three sections, a high-pressure cooling system and a low-pressure cooling system. The cooling system is composed of a total of six systems, which is the same system configuration as the ABWR.

The automatic decompression systems 20a and 20b are independent of the three-compartment cooling system and are constituted by a plurality of relief safety valves, and discharge high-pressure steam from the reactor pressure vessel 3 to reduce the pressure in the reactor. It is a safety facility that prevents an excessive pressure inside the reactor from being applied to the reactor pressure vessel 3 by forcibly lowering it. Further, since the automatic pressure reducing systems 20a and 20b lower the pressure in the furnace, the cooling water in the A residual heat removal systems 19a to 19c together with the A high pressure water injection system 23a and the B high pressure water injection system 23b is used. And the cooling function is improved.

Next, the operation of the above configuration will be described. In the emergency core cooling system at the time of an emergency reactor shutdown at the BWR-5 nuclear power plant, the first section of the reactor 1 is provided with the A high-pressure water injection system 23a for the reactor 1 from high pressure to low pressure in the reactor. Cooling water is injected into the reactor core 2 to cool the reactor 1.

When the pressure in the reactor is low and the pressure in the reactor is low, cooling water is injected from the A residual heat removal system 19a into the reactor core 2 to cool the reactor 1 and the reactor containment spray system 18a.
With this function, the cooling water is sprayed from the containment vessel sparger 14 via the heat exchanger 17 in a splay manner to spray-cool the inside of the containment vessel 13. In the second section as well, the B high-pressure water injection system 23b and the B residual heat removal system 19b cool the reactor 1 by injecting water into the core 2 at high pressure and low pressure, as in the first section, Perform spray cooling in 13.

In the third section, when the pressure inside the reactor is high, the cooling system 21 for isolating the reactor is used, and when the pressure is low, the C residual heat removing system 19 is used.
c, cooling water is injected into the reactor 1 to cool the reactor 1, and at the time of low pressure, the function of the reactor containment spray system 18 provided in the C residual heat removal system 19c is used. Perform spray cooling inside.

Normally, all the cooling systems in the three sections from the first section to the third section operate. Therefore,
For example, even if a coolant loss accident due to a pipe rupture or the like occurs in the first section and a single failure occurs in the cooling system in the second section, when the reactor pressure is high in the third section, the cooling system at the time of reactor isolation 21 In addition, when the pressure in the reactor is low, cooling water is injected into the reactor core 2 also from the C residual heat removal system 19c, and the reactor 1 is cooled.

In the C residual heat removal system 19c, the function of the reactor containment spray system 18 provided therein provides
Cooling water is sprayed from the containment vessel sparger 14 in a spray form to perform spray cooling in the containment vessel 13. Further, when the pressure inside the reactor 1 is excessively increased, the A automatic decompression system 20a and the B
b operates and discharges high-pressure steam from the reactor pressure vessel 3 to forcibly reduce the reactor pressure.

With the decrease in the furnace pressure, together with the A high pressure water injection system 23a and the B high pressure water injection system 23b in the first to third sections, the A residual heat removal systems 19a to 19C are used.
The cooling water injection function in c is improved, and the cooling effect of the reactor 1 is improved. In addition, since the furnace pressure is forcibly reduced, an excessive increase in the furnace pressure is prevented, so that mechanical safety of the reactor pressure vessel 3 is ensured and reliability is improved.

In the cooling water injection system of the BWR-5 according to the first embodiment, each of the three sections independently divided into two sections, a high-pressure cooling system and a low-pressure cooling system. Are provided in combination, and the cooling system is composed of a total of six systems, so that the same reliability and safety as the above-mentioned ABWR can be obtained.

Further, in the first embodiment, in the configuration of the emergency core cooling system or the like provided in the conventional BWR-5, the number of sections of the cooling water injection system, the number of various pumps, and the respective functions Has not changed. As a result, there is no need to change the basic equipment layout, piping and cable laying routes, etc. in the conventional BWR-5 nuclear power plant. Is easy to apply, and reliability and safety can be improved.

Since the second embodiment is a modification of the first embodiment according to the second embodiment, the description of the same components as those of the first embodiment and the operation thereof will be omitted. The following description focuses on the differences from the first embodiment. As shown in the system configuration diagram of FIG. 2, the emergency core cooling system for the reactor 1 includes a cooling water injection system having three independent sections, and two automatic pressure reducing systems.
a and 20b.

The first section includes an A high-pressure water injection system 23 capable of injecting cooling water into the reactor 1 when the pressure in the reactor is high to low.
a, with respect to the core 2 of the reactor 1 when the pressure in the reactor is low,
A residual heat removal system 24a with a core spray for spraying and injecting cooling water in a spray form.

The A residual heat removal system 24a with the core spray has a heat exchanger 17, and the reactor containment vessel 13
Via the containment sparger 14 in the reactor
It has a function of a reactor containment spray system 18 for performing spray cooling in the reactor containment 13.

The A residual heat removal system 24a with the core spray is different from the A residual heat removal system 19a of the first embodiment which is connected to the injection pipe in the reactor 1. It has the same configuration except that it is connected to a core spar sparger (not shown) which sprays cooling water in a reactor 2 in a spray shape in the reactor 1.

The second section is the same as the first section, and has a B high pressure water injection system 23b and a heat exchanger 17, and has a function of a reactor containment spray system 18 and a B residual heat removal system with a core spray. 24b, and the B residual heat removal system 24b with the core spray is provided with respect to the core 2 of the reactor 1.
It is connected to a core sparger (not shown) for spraying and injecting cooling water in a spray form.

The third section is the reactor 1 when the reactor pressure is high.
A reactor isolation cooling system 21 capable of injecting cooling water into the reactor, and a reactor containment spray system 18 having a heat exchanger 17 while injecting cooling water into the reactor 1 at low pressure. C having the same configuration as the A residual heat removal system 19a of the first embodiment.
And a residual heat removal system 19c. In addition, as in the first embodiment, the A automatic depressurizing system 20a and the B automatic depressurizing system 20b are safety facilities for the reactor pressure vessel 3 and improve the function of injecting cooling water into the reactor 1. A system is provided independently of the three-part cooling system.

The core A with the core spray of the first section was used.
The residual heat removal system 24a and the B residual heat removal system 24b with the core spray in the second section serve as core spargers connected in the reactor pressure vessel 3, for example, the high pressure core sparger 4 shown in FIG. It is easy to divert the low-pressure core sparger 7.

Next, the operation of the above configuration will be described. In the emergency core cooling system, the first section of the reactor 1 is configured such that cooling water is injected into the reactor core 2 from the high pressure to the low pressure of the reactor by the A high-pressure water injection system 23a to cool the reactor 1. Do. Also, when the pressure in the reactor is low, the reactor 1 is cooled by spraying cooling water evenly from the A residual heat removing system 24a with the core spray in a spray shape on the reactor core 2 by the reactor core sparger.

Further, an A residual heat removal system with a core spray
At 24a, the function of the reactor containment spray system 18
Cooling water is sprayed from the containment vessel sparger 14 via the heat exchanger 17 in a spray form to perform spray cooling in the containment vessel 13.

In the second section as well, by the B high pressure water injection system 23b and the B residual heat removal system 24b with the core spray, the cooling water is injected into the core 2 at high pressure and the core 2 at low pressure as in the first section. In addition, the cooling water is sprayed evenly in a spray form by a core sparger to cool the reactor 1 and to spray cool the reactor containment vessel 13.

In the third section, the cooling system 21 for isolating the reactor when the pressure inside the reactor is high, and the C residual heat removal system 19 when the pressure in the reactor is low.
c, cooling water is injected into the reactor core 2 to cool the reactor 1, and at the time of low pressure, the function of the reactor containment spray system 18 provided in the C residual heat removal system 19c is used.
Perform spray cooling in 13.

In the cooling water injection system for the BWR-5 according to the second embodiment, each of the three sections independently divided into two sections, a high-pressure cooling system and a low-pressure cooling system. And the cooling system is composed of a total of six cooling systems in the same manner as the ABWR, so that the same reliability and safety as the above-mentioned ABWR can be obtained.

Further, regarding the configuration of the emergency core cooling system and the like provided in the conventional BWR-5, for example, the high-pressure core sparger 4 and the low-pressure core sparger 7 are replaced with a residual heat removal system 24a with a core spray. It can be used as a 24b core sparger.

Therefore, the number of nozzles and pipes attached to the reactor pressure vessel 3 together with the number of sections of the coolant injection system, the number of pumps and their functions, and the BWR
The mechanism and function of the emergency core cooling system and the like provided in the -5 can be followed. Thereby, there is no need to change the arrangement of basic equipment and the route of laying pipes and cables in the conventional BWR-5 nuclear power plant. Therefore, compared to the first embodiment, the entire design standard is further reduced. It can be easily applied to BWR-5 without largely changing, and can improve reliability and safety.

[0067]

As described above, according to the present invention, an independent high-pressure cooling system for an emergency core cooling system for cooling a reactor in a BWR nuclear power plant during an emergency stop without changing the basic design of the BWR nuclear power plant. The system is divided into three sections by combining a system capable of injecting cooling water at the time of pressure and low pressure, and each section is provided with a spray cooling system in a reactor containment vessel.

Therefore, it is easy to apply the present invention to the BWR nuclear power plant, and at the same time, the cooling by injection of the cooling water when the pressure inside the reactor is high or low, and the cooling inside the containment vessel have high reliability. ABWR with improved safety
The equivalent of a nuclear power plant is obtained.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an emergency core cooling system according to a first embodiment of the present invention.

FIG. 2 is a system configuration diagram of an emergency core cooling system according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional emergency core cooling system.

FIG. 4 is a schematic configuration diagram of a conventional reactor containment vessel cooling system.

FIG. 5 is a system configuration diagram of a conventional BWR-5 emergency core cooling system.

FIG. 6 is a system configuration diagram of a conventional ABWR emergency core cooling system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor (BWR), 2 ... Core, 3 ... Reactor pressure vessel, 4 ... High pressure core spray sparger, 5 ... High pressure core spray pump, 6 ... High pressure core spray system, 7 ... Low pressure core spray sparger, 8 ... low pressure core spray pump, 9 ... low pressure core spray system, 10 ... injection pipe, 11 ... residual heat removal system pump, 12 ... residual heat removal system (RHR), 13 ... reactor containment vessel, 14 ... reactor containment spray Sparger, 15… suppression chamber, 16… pool water, 17… heat exchanger, 18
... Reactor containment spray system, 19a ... A residual heat removal system (RHR) with heat exchanger, 19b ... B with heat exchanger
Residual heat removal system, 19c: C residual heat removal system with heat exchanger, 20a: A automatic decompression system, 20b: B automatic decompression system, 21: Reactor isolation cooling system, 22: Reactor (ABWR), 23a ... A
High pressure water injection system, 23b B high pressure water injection system, 24a A residual heat removal system with A core spray, 24b ... residual heat removal system with B core spray.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Sato 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Yokohama Office (72) Inventor Takashi Kubootani 8-six Shin-Sugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Yokohama Office

Claims (2)

[Claims] In an emergency core cooling system of a nuclear power plant using a boiling water reactor, the emergency core cooling system is divided into three sections, and a first section and a second section each have a high internal pressure of the reactor. A high-pressure water injection system capable of injecting cooling water into the reactor from time to low pressure, and a residual heat removal system capable of injecting cooling water into the reactor at low pressure of the reactor pressure, and the residual heat removal system includes a heat exchanger. And the third section is provided with a reactor isolation cooling system capable of injecting cooling water into the reactor when the reactor pressure is high, and a reactor when the reactor pressure is low. A residual heat removal system capable of injecting cooling water therein is provided, and the residual heat removal system includes a heat exchanger to enable spray cooling in the reactor containment vessel,
An emergency core cooling system for a nuclear power plant, further comprising two automatic pressure reducing systems independent of the cooling system of the three sections. 2. An emergency core cooling system for a nuclear power plant using a boiling water reactor, wherein the emergency core cooling system is divided into three sections, and a first section and a second section each have a high internal pressure of the reactor. A high-pressure water injection system that can inject cooling water into the reactor from time to low pressure and a residual heat removal system that sprays cooling water into the upper part of the reactor core when the pressure in the reactor is low,
The residual heat removal system includes a heat exchanger to enable spray cooling in the reactor containment vessel, and the third section includes a reactor isolation cooling system that can inject cooling water into the reactor when the reactor pressure is high. And a residual heat removal system capable of injecting cooling water into the reactor when the pressure in the reactor is low, and the residual heat removal system includes a heat exchanger to enable spray cooling in the reactor containment vessel. An emergency core cooling system for a nuclear power plant, wherein two automatic pressure reducing systems independent of the cooling system of the three sections are provided.