JPS5913990A - Emergency core cooling system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an emergency core cooling system that injects pressure suppression pool water in a pressure suppression chamber into a reactor pressure vessel using water head pressure in an emergency.

[Technical background of the invention]

Boiling water reactors are equipped with an emergency core cooling system that injects cooling water into the reactor pressure vessel in the event of an emergency such as a loss of coolant accident, and maintains the core in a water-immersed state to ensure core cooling. It is provided.

Conventionally, such an emergency core cooling system has been configured to inject pressure suppression pool water stored in a pressure suppression chamber at the lower part of the reactor containment vessel into the reactor pressure vessel using a pump. However, such pumps are required to have characteristics such that the pump is normally on standby and can be activated in a short time in an emergency, and must also be configured to ensure power to the pump even in an emergency. For this reason, the equipment became complicated, its cost increased, and its maintenance and inspection was troublesome.

In order to eliminate such problems, a pressure suppression chamber is installed in the upper part of the reactor containment vessel, and this pressure suppression chamber and the reactor pressure vessel are connected by emergency water injection piping. A system was developed in which a valve in the middle of the piping is opened and water from the suppression pool in the pressure suppression chamber is injected into the reactor pressure vessel using head pressure.

[Problems with background technology]

The above-mentioned device does not require a pump or its power supply, so it has a simple structure, and has advantages such as low cost and easy maintenance. However, since the pressure suppression chamber is located above and water is injected using head pressure, in the event that the emergency water injection piping is damaged and leaks, the pressure suppression pool water will accumulate in the lower part of the reactor containment vessel. Moreover, this accumulated pressure suppression pool water cannot be returned to the pressure suppression chamber, and it is expected that the pressure suppression pool water will be in short supply. and,
In order to prevent such problems, the pressure suppression chamber has a large capacity, so that even if leaked pressure suppression pool water remains in the reactor containment vessel, its water level remains above the reactor core. shall be constructed to ensure immersion. For this reason, there was a problem that the pressure suppression chamber became larger and the construction cost increased. Furthermore, if pressure suppression pool water accumulates within the reactor containment vessel, equipment within the reactor containment vessel will be submerged in water, resulting in problems such as the equipment becoming unusable.

[Purpose of the invention]

The present invention prevents pressure suppression pool water from flowing into the reactor containment vessel even if the emergency water injection piping is damaged, making it possible to reliably maintain the reactor core in a water-immersed state, reducing the capacity of the pressure suppression chamber, and An object of the present invention is to obtain an emergency core cooling system capable of preventing equipment in a reactor containment vessel from being submerged in water.

[Summary of the invention]

The present invention provides a watertight living body shielding wall surrounding a reactor pressure vessel, and also provides an outflow prevention passage that opens into the living body shielding wall at one end and reaches the wall of the pressure suppression chamber at the other end. An emergency water injection pipe that communicates between the inside of the reactor pressure vessel and the inside of the reactor pressure vessel is housed within this outflow prevention passage. therefore,
Even if the emergency water injection piping is damaged and water leaks, the leaked pressure suppression pool water will flow through this outflow prevention passage into the biological shielding wall, and the water level inside this biological shielding wall will rise above the core. If this happens, the reactor core will be flooded with water. Therefore, the amount of pressure suppression pool water stored in the pressure suppression chamber is sufficient to raise the water level within this relatively small volume biological shield wall above the reactor core, and the volume of the pressure suppression chamber is small. Furthermore, since the pressure suppression pool water does not flow into the reactor containment vessel, equipment within the reactor containment vessel is not submerged in water.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1 in the diagram
The reactor containment vessel is airtight and pressure resistant. And, the central lower part l inside this reactor containment vessel 1
A reactor pressure vessel 2 is provided here, and a reactor core 3 is accommodated within this reactor pressure vessel 2. A living body shielding wall 4 is provided around the reactor pressure vessel 2.
is provided. This living body shielding wall 4 has a cylindrical shape,
In addition to being watertight, its inner diameter is relatively small enough to accommodate the reactor pressure vessel 2, and its internal capacity is also relatively small. Further, a pressure suppression section is formed in the upper part of the reactor containment vessel 1.

This pressure suppression jewel has an annular shape, and its interior is divided into a plurality of sections, for example, 4, by a radial interval W6, and some of these sections, for example, 2, are formed into pressure suppression sections G&, 5 m. , the other compartment is equipment storage compartment 5
b, 5b. Pressure suppression pool water 7 is stored in the pressure suppression sections 5* and 6*, and various devices (not shown) are accommodated in the equipment storage sections 5b and Sb. In addition, in this pressure suppression section, the water surface of the pressure suppression pool water 7 during normal times is above the reactor core 3, and a portion of this pressure suppression pool water 7 is filled into the biological shielding wall 4 up to the level above the reactor core 3. Furthermore, it is located at a position such that the water level within this pressure suppression section is above the core 3. Further, each pressure suppression section 5&, 5* is provided with a vent pipe 8...
The lower end of the reactor is immersed in the pressure suppression pool water 7, and the upper end communicates with the reactor containment vessel 1. Therefore, if coolant vapor leaks in the reactor containment vessel 1, this vapor will gush out into the pressure suppression pool water 2 through the vent pipes 8 and condense. It is configured to prevent a pressure increase within the containment vessel 1. (9) Pressure relief pipes 9 are connected to the reactor pressure vessel, and the tips of these pressure relief pipes 9 are immersed in the pressure suppression pool water 7. A pressure relief valve 1o... and a pressure relief safety valve 1no... are provided in the middle of these pressure relief pipes 9..., so that the pressure inside the reactor pressure vessel 2 exceeds a predetermined pressure. When the pressure rises, these pressure relief valves 10..., pressure relief safety valves 11... are opened, and the steam in the reactor pressure vessel 2 is released into the pressure suppression pool water 7. .

Further, reference numeral 12 represents an outflow prevention passage, one end of which passes through the biological shielding wall 4 and opens into the biological shielding wall 4, and the other end of which is pressure suppressed. room f
It has reached the wall. And this outflow prevention passage 12.
...Emergency water injection piping 13... is housed inside. These emergency water injection pipes 13... are pressure suppression sections 5a.

5a and the inside of the reactor pressure vessel 2 are communicated with each other.

Check valves 14 and emergency injection valves 15 are provided in the middle of these emergency water injection pipes 13.

Next, the operation of this embodiment will be explained. In an emergency, the emergency water injection valves 15 of the emergency water injection pipes 13 are opened, and the pressure suppression pool water 7 stored in the pressure suppression sections 5m and 5* is injected with water head pressure for emergency water injection. Piping 13・
... to inject water into the reactor pressure vessel 2 to cool the reactor core 3.

If the emergency water injection piping 13 is damaged and leakage occurs, the leaked pressure suppression pool water 7 flows into the biological shielding wall through the outflow prevention passage 12. Then, pressure suppression pool water r is placed inside this biological shielding wall 4.
If water accumulates and the water level rises above the core 3, the core 3 will be submerged in water, and cooling of the core 9 can be ensured. Since the volume inside this biological shielding wall 4 is relatively small, the amount of pressure suppression pool water 7 stored in the pressure suppression section 51° SIL is such that the water level inside this biological shielding wall 4 reaches above the reactor core 3. The volume of the pressure suppression sections 5a, 5* may be small because it is sufficient to raise the pressure. In addition, in the event that the pressure suppression pool water 7 leaks from this emergency injection pipe IS..., all of it will flow into the biological shielding wall 4 and will not flow into the reactor containment vessel 1. The equipment provided inside the container 1 will not be submerged in water.

Further, in this embodiment, the pressure suppression chamber 1 is divided into a plurality of sections, and a part of the sections is a pressure suppression section 5a.

51, and the remaining equipment storage compartment 5b.

5b, the space for accommodating equipment can be increased.

〔Effect of the invention〕

As described above, the present invention provides a watertight biological shielding wall surrounding the reactor pressure vessel, and an outflow prevention passage that opens into the biological shielding wall at one end and reaches the wall of the pressure suppression chamber at the other end. An emergency water injection pipe that communicates between the pressure suppression chamber and the inside of the reactor pressure vessel is housed within this outflow prevention passage. Therefore, even if the emergency water injection piping is damaged and water leaks, the leaked pressure suppression pool water will flow into the biological shielding wall through this outflow prevention passage, and the water level within this biological shielding wall will be lower than the reactor core. Once it reaches the top, the reactor core will be flooded with water. Therefore, the amount of pressure suppression pool water stored in the pressure suppression chamber is sufficient to raise the water level in the biological shielding wall, which has a comparative volume of about 100 yen, to above the reactor core, and the volume of the pressure suppression chamber is small. Furthermore, since the pressure suppression pool water does not flow into the reactor containment vessel, the equipment within the reactor containment vessel will not be submerged in water, which has great effects.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, with Figure 1 being a longitudinal sectional view and Figure 2 being a longitudinal sectional view.
The figure is a sectional view taken along line II-II in FIG. 1. I... Reactor containment vessel, 2... Reactor pressure vessel, 3
...Reactor core, 4...Biological shielding wall.

Claims (2)

[Claims] (1) The reactor pressure vessel that houses the reactor core, the watertight living body shielding wall that surrounds the reactor pressure vessel, and the water surface of the pressure suppression pool that is housed outside the living body shielding wall. a pressure suppression chamber located at least above the reactor core; and an outflow prevention passageway that opens into the biological shielding wall at one end and reaches the wall surface of the pressure suppression chamber at the other end;
Emergency water injection piping is provided in the outflow prevention passage and communicates the pressure suppression chamber with the reactor pressure vessel, and in an emergency, injects the pressure suppression pool water in the pressure suppression chamber into the reactor pressure vessel using water head pressure. An emergency core cooling system characterized by comprising: (2) The pressure suppression chamber has an annular shape, and its interior is divided into a plurality of compartments by radial partition walls, with some of these compartments serving as pressure suppression compartments and others serving as equipment storage compartments. A patented emergency core cooling system featuring: