JP5526094B2 - Emergency condenser and nuclear reactor system equipped with the same - Google Patents

Description

  The present invention relates to an emergency condenser and a nuclear reactor system equipped with the same, and in particular, cooling water obtained by condensing steam from a main steam pipe at the reactor outlet in an emergency condenser in an emergency water tank, The present invention relates to an emergency condenser that is suitable for being returned to a main water supply pipe at a reactor inlet and a nuclear reactor system including the emergency condenser.

  In a nuclear power plant having a boiling water reactor, the reactor is cooled by the isolated core cooling facility by isolating the reactor and the steam turbine facility in an emergency where the reactor cooling cannot be expected in the steam turbine facility.

FIG. 1 shows a configuration example of a conventional emergency condenser type cooling system for mold isolation.
As shown in the figure, a main feed water pipe 2 and a main steam pipe 3 are connected to the nuclear reactor 1, and cooling water from the main feed water pipe 2 is heated by fuel inside the reactor 1 and generated steam. Is discharged from the main steam pipe 3 to drive the steam turbine. The reactor 1 is surrounded by a reactor containment vessel 4, and an isolation valve 5 is installed in the main steam pipe 3 and a check valve 6 is installed in the main feed water pipe 2. By closing the isolation valve 5, the reactor containment vessel The inside and outside of 4 can be isolated.

  An emergency water tank 7 is provided above the reactor containment vessel 4, and one pipe of the condenser 8 in the emergency water tank 7 is connected to the main steam pipe 3 inside the reactor containment vessel 4. The other pipe of the condenser 8 is connected to the main water supply pipe 2 inside the reactor containment vessel 4.

  Thereby, even when the inside and outside of the reactor containment vessel 4 are isolated, the reactor 1 can be cooled.

  As such an isolation core cooling facility, there are two types: a turbine drive pump type described in Patent Document 1 and an emergency condenser type described in Patent Documents 2 and 3.

  The turbine-driven pump type described in Patent Document 1 uses a turbine-driven pump that operates with steam from the main steam pipe at the reactor outlet, and supplies cooling water from the condensate storage tank or pressure suppression pool to the reactor inlet. Return to the main water supply pipe.

  On the other hand, in the emergency condenser type described in Patent Document 2, steam from the main steam pipe at the reactor outlet is condensed in an emergency condenser in the emergency water pool to form cooling water. Is returned to the main water supply pipe at the reactor inlet.

  Furthermore, the emergency condenser type | mold described in patent document 3 supplies cooling water to the condenser using the water injection pump which does not depend on an emergency power supply from a water source.

  None of these require a special external power source. In Patent Documents 1 and 2, since only the steam from the reactor is used as the driving source, the main water supply water is supplied even when the cooling pump does not operate due to power loss or the like. Cooling water can be supplied to the piping to cool the reactor.

JP 2005-172482 A Japanese Patent Laid-Open No. 08-136665 Japanese Patent Laid-Open No. 08-248166

  By the way, in order to maximize the functions of the isolation core cooling facility and improve the performance, it is desirable that the reactor can be cooled for a long time by static means without using a power source or dynamic equipment.

  In particular, when the reactor is cooled using an emergency condenser, the water in the emergency water tank evaporates and depletes over time, and the emergency condenser does not operate. If provided, the reactor can be cooled effectively by operating the emergency condenser for a long time.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an emergency condenser and an emergency condenser that can effectively cool a nuclear reactor for a long time even when a cooling pump does not operate due to loss of power. It is to provide a nuclear reactor system equipped.

In order to achieve the above object, the emergency condenser of the present invention is connected to one of the main steam pipes of the reactor and the other to the main water supply pipe for supplying cooling water to the reactor, In an emergency condenser comprising a condenser for condensing the main steam of the main steam pipe and returning it to the main water supply pipe, and an emergency water tank containing the condenser, the emergency water tank has a plurality of A buffer tank is connected to one of the emergency water tanks in each gas phase portion, and the other emergency water tank and the buffer tank are connected to each other in a liquid phase portion, and the two emergency water tanks are connected. Pour water from the buffer tank into the emergency water tank using pressure difference,
Alternatively, each of the emergency water tanks has a buffer tank, and each of the emergency water tanks and each of the buffer tanks is connected to a gas phase part by a gas phase part pipe. In addition, the gas phase portions of the respective emergency water tanks are connected by a connecting pipe, and the liquid phase portions of at least two emergency water tanks connected by the connecting pipe are respectively connected by the gas phase portions by the gas phase portion piping. The liquid phase part of the buffer tank is not connected to the liquid phase part by a liquid phase cross pipe, and the liquid phase part cross pipe is used to supply water from the buffer tank by using a pressure difference between the two emergency water tanks. Water is poured into the emergency water tank through

  In order to achieve the above object, a nuclear reactor system according to the present invention is installed in a nuclear reactor, a nuclear reactor containment vessel surrounding the nuclear reactor, an outside of the nuclear reactor containment vessel, and a main steam of the nuclear reactor. One condenser is connected to the pipe, the other is connected to a main water supply pipe for supplying cooling water to the nuclear reactor, and the condenser for condensing the main steam of the main steam pipe and returning it to the main water supply pipe and the condenser In the nuclear reactor system provided with an emergency condenser comprising an emergency water tank with a built-in water, the emergency condenser is an emergency condenser having the above-described configuration.

  According to the present invention, even when the cooling pump does not operate due to power loss or the like, water can be injected into the emergency water tank using static means, and the reactor can be cooled for a long time.

It is a figure which shows schematic structure of the cooling system at the time of isolation of the conventional emergency condenser. It is a block diagram which shows Example 1 of the emergency condenser of this invention. It is a figure for demonstrating the operation | movement of each apparatus of the emergency condenser of Example 1 of this invention, and the change of the state quantity of each part.

  Hereinafter, the emergency condenser of the present invention will be described based on the illustrated embodiment. Note that the same reference numerals are used for the same reference numerals as before.

  Example 1 of the emergency condenser of the present invention is shown in FIG. In the first embodiment shown in FIG. 2, although not shown in particular, the condenser housed in the emergency water tank is connected to the main steam pipe and the main water supply pipe from the reactor as in FIG. Yes. Moreover, in Example 1, the case where an emergency condenser has two systems (A, B) is shown.

  In the emergency condenser of this embodiment shown in the figure, an emergency water tank 7A containing a condenser 8A and a buffer tank 9A are connected to each other by a gas phase pipe 10A. The emergency water tank 7B containing the 8B and the buffer tank 9B are connected to each other by a gas phase piping 10B. The buffer tank 9A and the emergency water tank 7B are connected to each other by a cross pipe 11A, while the buffer tank 9B and the emergency water tank 7A are connected to each other by a cross pipe 11B. Yes. Further, a check valve 12A is provided in the cross pipe 11A, and a check valve 12B is provided in the cross pipe 11B. Water from the emergency water tank 7B to the buffer tank 9A and from the emergency water tank 7A to the buffer tank 9B, respectively. Prevents backflow.

  The emergency water tank 7 </ b> A and the emergency water tank 7 </ b> B have connection pipes 13 </ b> A and 13 </ b> B whose one ends are connected to the respective gas phase portions, and the other of the connection pipes 13 </ b> A and 13 </ b> B is connected to the three-way valve 14. An air release pipe 15 provided in the three-way valve 14 is open to the atmosphere. The three-way valve 14 is a valve that alternately connects the connection pipe 13A and the atmosphere release pipe 15, and the connection pipe 13B and the atmosphere release pipe 15, and is mechanically switched by a piston structure or the like due to a pressure difference between the connection pipe 13A and the connection pipe 13B. It has become. That is, one side of the three-way valve 14 is opened to the atmospheric pressure, and when the pressure difference between the remaining two sides of the three-way valve 14 coupled to the connecting pipes 13A and 13B becomes a specified value or more, the pressure is released to one of the higher pressures and the atmospheric pressure. Thus, the three-way valve 14 is switched so that one of them communicates and one of the low pressure and one of the ones opened to the atmospheric pressure are cut off.

  In addition, in each gas phase portion of the emergency water tank 7A and the emergency water tank 7B, safety valves 16A and 16B that are operated when a pressure higher than a specified value is applied to the emergency water tanks 7A and 7B are provided. When the pressure in 7A, 7B becomes a specified value or more, the safety valves 16A, 16B operate to open the emergency water tanks 7A, 7B to the atmosphere.

  Further, the buffer tank 9A and the buffer tank 9B are respectively connected to the separate water injection sources 17A and 17B at the liquid phase portion, and gravity water injection is possible from the water injection source 17A to the buffer tank 9A and from the water injection source 17B to the buffer tank 9B. It has become. The separate water injection sources 17A and 17B keep the gas phase part open to the atmosphere when the emergency condenser type isolation cooling system is in operation.

  Next, the operation of each device and the change in the state quantity of each part in a typical case of the first embodiment will be described with reference to FIG.

  In the figure, time (1) is immediately after the three-way valve 14 is switched to the A system closed and the B system opened (atmospheric release). The emergency water tank 7A is full (water level L1), the emergency water tank 7B is low (water level L0). Similarly, the buffer tank 9A is full (water level BL1), and the buffer tank 9B is low (water level BL0). ). The emergency water tank 7B is in a state where the water temperature is high (water temperature T1: saturation temperature) due to heat from the condenser 8B, and the emergency water tank 7A is in a state where the water temperature is low (water temperature T0) after pouring water from the buffer tank 9B. Suppose there is. Both pressures are atmospheric pressure (pressure P0).

  At time (1), the temperature of the emergency water tank 7A is a low temperature below the saturation temperature, so the temperature gradually rises due to the heat from the condenser, and reaches the saturation temperature T1 at time (2). During this time, since there is no boiling, the pressure in the emergency water tank 7A hardly increases and the water level hardly changes. On the other hand, since the water in the emergency water tank 7B is at the saturation temperature T1, it continues to boil after time (1), and the temperature does not change at T1, but at time (2), the water level reaches the water level LL that requires water supply.

  In addition, a water injection source 17B is installed in connection with the buffer tank 9B, and since the pressure is atmospheric pressure, gravity water is injected from the water injection source 17B to the buffer tank 9A, and the water level of the buffer tank 9A is restored.

  After the time (2), the water in the emergency water tank 7A starts to boil and the pressure gradually increases from P0. At this time, since the gas phase portions of the emergency water tank 7A and the buffer tank 9A are in communication, the pressure in the buffer tank 9A similarly increases. When the pressure difference between the emergency water tank 7A and the emergency water tank 7B exceeds the head difference due to the water level between the emergency water tank 7B and the buffer tank 9A, water injection from the buffer tank 9A to the emergency water tank 7B starts. As the water level in the emergency water tank 7B rises and the water level in the buffer tank 9A falls, the head difference between the two increases, and the pressure in the emergency water tank 7A and the buffer tank 9A increases. When the time (3) is reached and this pressure reaches the pressure P1 corresponding to the full water in the emergency water tank 7B, the three-way valve 14 is switched.

  The state immediately after the time (3) is a state in which the A system and the B system are reversed at the time (1). Therefore, after the time (3), the state from the time (1) to (3) described above is alternately repeated in the A system and the B system.

  As described above, water is repeatedly poured into the emergency water tanks 7A and 7B, and the functions of the condensers 8A and 8B of the emergency condenser continue until the water injection sources 17A and 17B are depleted even when the power is lost. Since the water injection sources 17A and 17B can be placed at a low position, by providing the water injection ports 18A and 18B, it is possible to supply water by connecting from an external water source.

  Even if the system does not function due to a failure of a valve used, the emergency water tank is provided with safety valves 16A and 16B having a set pressure P2, so that the pressure does not exceed P2. If a plurality of safety valves are provided, it is possible to cope with a single failure of the safety valve. Therefore, it has the function of the conventional emergency condenser type isolation cooling facility, and does not fall below this.

  When water vapor flows into the buffer tanks 9A and 9B from the emergency water tanks 7A and 7B, if condensation occurs in the buffer tanks 9A and 9B, the pressure in the buffer tanks 9A and 9B does not increase, and the emergency water tank 7B Cannot pour water into 7A.

  Therefore, partition plates 19A and 19B having a heat insulating structure for separating the water region and the water vapor region are provided on the water surfaces in the buffer tanks 9A and 9B. The partition plates 19A and 19B can be floated on the water surface by using a partition plate having a hollow structure.

  In addition, in order to avoid a pressure drop due to heat radiation to the outside, it is desirable that the buffer tanks 9A and 9B, the pipes 10A and 10B, and the emergency water tanks 7A and 7B have a heat insulating structure on the outer periphery.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the present invention can be easily applied to a pressurized water reactor other than a boiling water reactor. In this case, a reactor coolant outlet pipe may be used instead of the main steam pipe.

  For example, although the above-described embodiment has been described by taking an emergency water tank as an example, the present invention is not limited to this, and application of the water tank is not hindered as long as it is a water tank.

  Further, for example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.

  Further, a 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. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Reactor, 2 ... Main water supply piping, 3 ... Main steam piping, 4 ... Reactor containment vessel, 5 ... Isolation valve, 6, 12A, 12B ... Check valve, 7, 7A, 7B ... Emergency water tank, 8 8A, 8B ... Condenser, 9A, 9B ... Buffer tank, 10A, 10B ... Gas phase section piping, 11A, 11B ... Cross piping, 13A, 13B ... Connection piping, 14 ... Three-way valve, 15 ... Air release piping, 16A , 16B ... Safety valve, 17A, 17B ... Water injection source, 18A, 18B ... Water injection port, 19A, 19B ... Partition plate.

Claims (8)

One is connected to the main steam pipe of the nuclear reactor, and the other is connected to the main water supply pipe that supplies cooling water to the reactor, and condenses the main steam of the main steam pipe and returns it to the main water supply pipe And an emergency condenser having an emergency water tank containing the condenser,
There are a plurality of emergency water tanks, and one of the emergency water tanks is connected to a buffer tank at each gas phase portion, and the other emergency water tank and the buffer tank are connected at each liquid phase portion. And the emergency condenser which pours the water of the said buffer tank into the said emergency water tank using the pressure difference of two said emergency water tanks. One is connected to the main steam pipe of the nuclear reactor, and the other is connected to the main water supply pipe that supplies cooling water to the reactor, and condenses the main steam of the main steam pipe and returns it to the main water supply pipe And an emergency condenser having an emergency water tank containing the condenser,
A plurality of the emergency water tanks, and each of the emergency water tanks has a buffer tank, and each of the emergency water tanks and each of the buffer tanks has a gas phase part connected by a gas phase part pipe, and The gas phase parts of the emergency water tanks are connected by a connecting pipe, and the liquid phase parts of at least two emergency water tanks connected by the connecting pipes are connected by the gas phase part pipes. The liquid phase part of the buffer tank is not connected to the liquid phase part of the buffer tank by a liquid phase part cross pipe, and the liquid phase part cross pipe is used for the water of the buffer tank by utilizing the pressure difference between the two emergency water tanks. An emergency condenser for pouring water into the emergency water tank. The emergency condenser according to claim 2,
A three-way valve is provided in the connection pipe, one of the three-way valves is opened to atmospheric pressure, and when the pressure difference between the remaining two directions of the three-way valve coupled to the connection pipe exceeds a specified value, The emergency condenser is characterized in that the three-way valve is switched so that the one open to the atmospheric pressure communicates, and the one of the low pressure and the one opened to the atmospheric pressure is blocked. The emergency condenser according to claim 2 or 3,
An emergency condenser having a check valve in the liquid phase cross pipe to prevent a back flow of water from the emergency water tank to the buffer tank. The emergency condenser according to any one of claims 2 to 4,
A water injection source connected to each liquid phase portion of each buffer tank by a water injection pipe is provided, and gravity water injection from the water injection source to the buffer tank is enabled based on a liquid level difference between the water injection source and the buffer tank. An emergency condenser having a check valve in the water injection pipe to prevent back flow of water from the buffer tank to the water injection source. The emergency condenser according to any one of claims 2 to 5,
Each emergency water tank is provided with a safety valve that operates at a pressure equal to or higher than a specified value, and when the pressure in the emergency water tank exceeds a specified value, the safety valve operates to open the emergency water tank to the atmosphere. An emergency condenser. The emergency condenser according to any one of claims 1 to 6,
An emergency condenser having a heat insulating partition plate separating a water region and a water vapor region on a liquid level of the buffer tank. A reactor, a reactor containment vessel surrounding the reactor, and one outside the reactor containment vessel, one of which is connected to the main steam pipe of the reactor, and the other is supplied with cooling water to the reactor An atom comprising a condenser connected to a main water supply pipe for supplying water, condensing main steam of the main steam pipe and returning it to the main water supply pipe, and an emergency condenser comprising an emergency water tank containing the condenser In the furnace system,
The reactor system according to any one of claims 1 to 9, wherein the emergency condenser is the emergency condenser according to any one of claims 1 to 9.

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