JPH03274494A - Cooling facility for nuclear power station - Google Patents

Abstract

PURPOSE:To enable improvement of nuclear reactor safety by making a valve provided to the second and the third pipings of the first to the third pipings, to be opened by coincidence of a loss of coolant accident signal and a water source level low signal of a gravity falling water injection system. CONSTITUTION:In a water pool 33 which is provided at an upper part outside a nuclear reactor containment vessel 22 as a cooling water source, an emergency condenser 32 is placed, and the condenser 32, a nuclear reactor pressure vessel 21 and a gaseous phase part are connected each other by a steam supplying piping 31 which is the first piping. Also a condensate returning piping 34 which is the second piping connecting a condenser 32 and the pressure vessel 21, connects the condenser and the pressure vessel via a valve which is normally closed. Moreover, a purging tube 36 of incondensable gases which is the third piping connecting the condenser 32 and a suppression pool 25, is also provided by a valve 37 which is normally closed. The valves 35 and 37 provided to the pipings 34 and 36 are constituted by utilizing a controlling device, so as to open when all of the loss of coolant accident signal and the water source level low signal of the gravity falling water injection system as well as a nuclear reactor pressure high signal, fully coincide. With this constitution, the emergency condenser can be appropriately actuated.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to cooling equipment for nuclear power plants.

(Conventional technology) Nuclear power plants are equipped with cooling equipment to remove decay heat generated from the reactor core for a long period of time after an accident to the outside of the reactor containment vessel in case a loss of coolant accident occurs. It is provided.

FIG. 2 is a schematic diagram of the cooling equipment of a conventional nuclear power plant. The reactor core 1 is housed in a reactor pressure vessel 2. This reactor pressure vessel 2 is housed in a reactor containment vessel 3. A main steam pipe 4 is connected to the reactor pressure vessel 2 and is configured to send steam generated within the reactor pressure vessel 2 to a turbine (not shown). Further, a water supply pipe 5 is connected to the reactor pressure vessel 2, and is configured to supply coolant through a turbine and a condenser (not shown). A suppression pool 6 is installed at the bottom of the reactor containment vessel 3. A vent pipe 7 is installed in the suppression pool 6, with one end opening into the pool water 6a stored in the suppression pool 6 and the other end opening into the space 3a of the reactor containment vessel 3. There is. Further, a vacuum breaker valve 8 is provided above the suppression pool 6. The containment vessel cooling pump 9 is installed below the reactor containment vessel 3, and pumps pool water 6a in the suppression pool 6 through the containment vessel cooling piping 10.
It is configured to circulate. The heat exchanger 11 for cooling the containment vessel is installed downstream of the pump 9 for cooling the containment vessel, and is connected to a water source 12 such as the sea, a pond, or a river, a water intake pipe 13, and a drainage pipe 1.
It is configured to exchange heat through the 4. The circulation pump 15 is installed in the water intake pipe 13. The containment vessel cooling pump 9 and the circulation pump 15 are configured to receive power from a regular power source 17 and an emergency diesel generator 18 via a cable 16.

In the above configuration, when an accident occurs, decay heat is transferred to the suppression pool 6. The decay heat stored in the suppression pool 6 in the reactor containment vessel 3 is transmitted to the secondary side outside the reactor containment vessel 3 by the containment vessel cooling pump 9 and the containment vessel cooling heat exchanger 11. The heat on the secondary side is transferred by a circulation pump 15 to a water source 12 such as the sea, which is the final heat release site.

In this way, conventional facilities for removing decay heat from reactor containment vessels include dynamic pumps, heat exchangers, emergency diesel generators that are the power source for driving the pumps, and piping that connects these devices. , electric cables, etc. Furthermore, in order to ensure a high degree of reliability, multiple systems of the above equipment are installed independently. Therefore, a huge amount of material was required.

(Problems to be Solved by the Invention) As mentioned above, in the case of a loss of coolant accident, the conventional cooling equipment of a nuclear power plant uses a dynamic drive source to remove the decay heat generated in the reactor core. This required system equipment consisting of a large number of devices that required

An object of the present invention is to provide cooling equipment for a nuclear power plant that can reduce dynamic drive sources such as pumps and stably remove decay heat generated in a reactor core over a long period of time.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a reactor pressure vessel accommodating a reactor core, a reactor containment vessel accommodating this reactor pressure vessel, and a reactor pressure vessel accommodating a reactor core. A cooling water source provided at a high position, an emergency condenser housed in the cooling water source, and a first pipe connecting the emergency condenser and the gas phase portion of the reactor pressure vessel. , a second pipe connecting the emergency condenser and the reactor pressure vessel; and a second pipe connecting the emergency condenser and a suppression pool formed in the reactor containment vessel and containing pool water. 3, and a control device that opens valves provided in the second and third pipes in response to a coincidence of a loss of coolant accident signal and a low water source water level signal of a gravity drop type water injection system. Provide cooling equipment for power plants.

(Function) The second pipe connects the emergency condenser and the reactor pressure vessel, and the third pipe connects the emergency condenser and the suppression pool.
The normally closed valves installed in the piping of the reactor are opened when the loss of coolant accident signal coincides with the water source water level low signal of the gravity drop water injection equipment. It is led from the reactor pressure vessel to the emergency condenser via the first pipe, and is cooled and condensed within the heat transfer tube.

The condensed steam becomes condensed water and returns to the reactor pressure vessel via the second pipe due to the water head difference. The latent heat held by the steam is transferred to the cooling water source outside the reactor containment vessel via the heat transfer tubes of the emergency condenser. Further, the non-condensable gas mixed in the emergency condenser is discharged into the suppression pool from the third pipe.

(Example) Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 is a schematic diagram of an embodiment of the present invention.

The reactor core 20 is housed in a reactor pressure vessel 21 .

This reactor pressure vessel 21 is housed in a reactor containment vessel 22. Piping such as a main steam pipe 23 is connected to the reactor pressure vessel 21 . A suppression pool 25 and a vent pipe 26 are installed in the lower part of the reactor containment vessel 22. Further, a vacuum breaker valve 27 is installed above the suppression pool 25.

A pressure reducing valve 28 is installed in the main steam pipe 23 and is configured to open and close a flow path of an exhaust pipe 29 opened into the reactor containment vessel 22 . The pressure reducing valve 28 opens in response to an accident signal, etc., and quickly depressurizes the reactor and returns it to the gravity drop type water injection equipment 3.
0 is configured to facilitate coolant injection. An emergency condenser 32 is installed in a water pool 33 that is a cooling water source provided at the top outside the reactor containment vessel 22.
The emergency condenser, the reactor pressure vessel, and the gas phase section are connected by a steam supply pipe 31, which is a first pipe. In addition, a second
The condensed water return pipe 34, which is the pipe of
and reactor pressure vessel 2] are connected via a normally closed valve 35. Emergency condenser 32 and suppression pool 2
Non-condensable gas exhaust pipe 3 which is the third pipe connecting with 5
6 is also provided with a normally closed valve 37. These second
The valves 35 and 37 installed in the third piping 34 and 36 are controlled by the control device to send a coolant loss accident signal and a water source for the gravity drop type water injection equipment in addition to the reactor pressure high signal, which is a conventional operating signal. It is configured to open even when the water level signal is low.

When the emergency condenser of this embodiment operates as a reactor isolation cooling system, the valve 35 provided in the second pipe opens in response to a reactor pressure high signal, as in conventional equipment.

On the other hand, if only the loss of coolant accident signal is used as the activation signal for the emergency condenser, which serves as the containment vessel cooling system, in the event of a main steam pipe rupture, etc., the second There is a risk that the valves in the pipes will open and the coolant in the reactor pressure vessel will flow out and be lost. However, a low water source water level signal for gravity-drop water injection equipment indicates that the reactor pressure has dropped sufficiently, and if this signal and the coolant loss accident signal match as the activation signal, the emergency condensate equipment can be operated properly.

Therefore, according to this embodiment, even in the event of a loss of coolant accident, the emergency condenser is operated as a cooling facility for the reactor at an appropriate time, and the decay heat generated in the reactor core is used to utilize natural forces such as gravity. Since heat can be removed to the outside of the reactor containment vessel, it is possible to remove decay heat over a long period of time without using a dynamic drive source such as a pump that circulates cooling water and a power source that supplies power to it.

〔Effect of the invention〕

According to the present invention, the emergency condenser can be operated as cooling equipment for the reactor at an appropriate time even in the event of a loss of coolant accident, so the safety of the reactor can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the cooling equipment for a nuclear power plant according to the present invention, and Fig. 2 is a schematic diagram showing a conventional cooling equipment for a nuclear power plant.
1... Reactor pressure vessel 22... Reactor containment vessel
23...Main steam pipe 25...Suppression pool

Claims (1)

[Claims] A reactor pressure vessel that accommodates the reactor core, a reactor containment vessel that accommodates the reactor pressure vessel, a cooling water source provided at a position higher than the reactor core, and emergency condensate contained in this cooling water source. a first pipe connecting the emergency condenser and the gas phase part of the reactor pressure vessel; a second pipe connecting the emergency condenser and the reactor pressure vessel; The third piping connecting the emergency condenser and the suppression pool that is formed in the reactor containment vessel and containing pool water, and the valves installed in these second and third piping, were damaged in a loss of coolant accident. Cooling equipment for a nuclear power plant, comprising a control device that opens when a signal and a water source water level low signal of a gravity drop type water injection system match.