JPH0643279A - Integral pressurized water reactor - Google Patents

Abstract

PURPOSE:To prevent a poison from being heated to a high temperature by the high-temperature primary cooling water by increasing the heat-insulating effect of a poison tank. CONSTITUTION:The wall faces 50 (52) of a poison tank 24 are formed into a double structure made of stainless steel plates 64, 66 (74, 76), and heat insulating materials 70 (80) are filled in cavities 68 (78) formed between them. The heat insulating materials 70 (80) can be used without being wetted by the primary cooling water and a poison 60, thus the heat-insulating effect can be increased. Gas is fed to the cavities 68 (78) from a pressure device 82 to pressurize the whole cavities 68 (70) to nearly the same pressure as the pressure of the primary cooling water 58, and the collapse of the cavities 68 (78) and the deformation of the poison tank 24 itself can be prevented.

Description

Detailed Description of the Invention

[0001]

This invention relates to SPWR (System-i
integrated pressurized water reactors (system integrated pressure water reactors, etc.) that prevent the poison in the poison tank, which is provided in the pressure vessel for stopping the reactor, from becoming high temperature due to the primary cooling water. is there.

[0002]

2. Description of the Related Art SPWR is a new concept light water reactor in which all primary cooling systems (circulation pump, steam generator, pressurizer, etc.) are built in the reactor pressure vessel, and control rods are abolished to start and stop the reactor. It is characterized in that steady operation, load following operation, etc. are performed by adjusting the reactivity temperature coefficient of the core and the boron concentration in the primary system, and a poison tank is built in the reactor pressure vessel for reactor shutdown in the event of an abnormality. .

An outline of SPWR is shown in FIG. SPWR1
No. 0 reactor pressure vessel 12 (reactor vessel barrel) has a cylindrical shape, and is supported on a foundation 16 by legs 14. A pressurizing chamber 18 is formed in the upper part of the reactor pressure vessel 12, a through-flow helical coil steam generator 20 is arranged in the middle part, and a core 22 (fuel assembly) is arranged in the lower part.
A reactor stop poison tank 24 containing high-concentration boric acid water is arranged around the core 22 so as to wrap the core 22.

A main circulation pump 26 is inserted from the top of the reactor pressure vessel 12, and by driving the main circulation pump 26,
The secondary cooling water circulates in the primary cooling water passage 28 indicated by the solid arrow. The water supply for steam generation is supplied from the water supply header 30,
As shown by the dotted arrow, while passing through the steam generator 20, it exchanges heat with the primary cooling water to become steam, which is discharged from the steam header 32.

The pressurizing chamber 18 has a free liquid surface 34 (water surface of primary cooling water). An electric heater 36 is arranged in the pressurizing chamber 18, and current is applied to evaporate water to pressurize the electric power as needed. The water in the pressurizing chamber 18 and the primary cooling water are connected via the cooling body distributor 38, and the structure is such that only the pressure is transmitted to the primary cooling water without transmitting the temperature. A decompression spray 48 for decompression is provided on the upper part of the pressurizing chamber 18, and water from the outside or the outlet of the steam generator 20 is supplied.

A poison flow passage 40 (mixing preventer) having a honeycomb structure is arranged at the bottom of the poison tank 24, and the poison and primary cooling water are in contact with each other in a state of being separated by a density difference. A poison thermal expansion absorber 42 is arranged around the poison flow passage 40. The upper part of the poison tank 24 is connected to the primary cooling water via a water pressure actuating valve 44 that works with the projecting pressure of the main circulation pump 26. This valve 44
Is closed during normal operation of the furnace, and is automatically opened by gravity falling of the valve element when the discharge pressure of the main circulation pump 26 decreases (pump power supply is lost, water level decreases, etc.). When opened, the poison in the poison tank 24 is injected into the core 22 from the poison flow passage 40 by natural circulation based on the density difference with the primary cooling water, and the furnace is stopped.

In addition, an active stop valve 46 is provided for emergency stop of the furnace.
An active stop system having is connected to the upper part of the poison tank 24 from the steam generator inlet plenum (the discharge port of the main circulation pump 26).

In the SPWR, the primary cooling water and the poison in the poison tank 24 are partitioned by the inner and outer wall surfaces 50 and 52 of the poison tank 24. In this case, the temperature of the primary cooling water reaches about 320 ° during steady operation,
Poison needs to be kept at about 150 ° C. or less in order to keep the density difference with the primary cooling water. For this reason, it is necessary to make the poison tank an adiabatic structure so that the heat of the primary cooling water is not transmitted to the poison. As this heat insulating structure, conventionally, as shown in FIG. 3A, heat insulating materials 54 and 56 are attached to the inner peripheral surfaces of the wall surfaces 50 and 52 of the poison tank 26, or as shown in FIG. It has been considered that the heat insulating materials 54 and 56 are attached to the outer peripheral surface side.

[0009]

According to the above conventional heat insulating structure, the heat insulating materials 54 and 56 are used by immersing them in the poison 60 or the primary cooling water 58. However, the existing heat insulating material is sufficient in water. There was no one that showed a good heat insulation effect. Therefore, it is difficult to suppress the temperature of the poison 60 to 150 ° C. or lower in the conventional heat insulating structure.

The present invention is intended to solve the problems in the prior art and to provide an integrated pressurized water reactor having a heat insulating structure capable of reliably suppressing the temperature rise of the poison in the poison tank.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a poison tank having a reactor pressure vessel filled with a poison for reactor shutdown, and an atom in which a passage for primary cooling water is formed around the poison tank. In the furnace, the wall surface of the poison tank that comes into contact with the primary cooling water has a double structure, and a cavity that is cut off from the poison and the primary cooling water is formed between the wall surfaces of the double structure. Is filled with a heat insulating material and the inside of this cavity is pressurized by a pressure means.

[0012]

According to the present invention, the wall surface of the poison tank can be
Since a cavity is formed with a heavy structure and the heat insulating material is filled in it, the heat insulating material can be used without contact with the poison and the primary cooling water, and sufficient insulation can be achieved even with the existing heat insulating material. The effect can be obtained. Also, during steady operation, the primary cooling water is pressurized to, for example, about 130 kg / cm ² , but since the inside of the double-structured cavity is pressurized by the pressurizing means, the cavity is filled with the primary cooling water pressure. It is possible to prevent crushing and deformation of the poison tank.

[0013]

FIG. 1 shows an embodiment of the present invention. This SP
The WR 10 is the same as the SPWR 10 in FIG. 2 except for the heat insulating structure of the poison tank 24 and the pressurizing structure of the heat insulating structure.

In FIG. 1, the poison tank 24 is arranged so as to surround the reactor core 22, forms a single communicating space as a whole, and the poison (high-concentration boric acid water) is accommodated in this space. Outer wall surface 52 of poison tank 24
Of the primary cooling water flow path 28 on the outer side of the
Is configured. The upper portion of the poison tank 24 is partitioned from the primary cooling water by the hydraulically operated valve 44, and the bottom portion is in contact with the primary cooling water in the poison flow passage 40 in a state of being separated from the primary cooling water by a density difference.

Inner and outer wall surfaces 50, 52 of the poison tank 24
Has a double structure as shown in FIG. That is, the wall surface 50 is formed by arranging plates 64 and 66 of stainless steel or the like facing each other with a predetermined gap d therebetween to form a cavity 68 isolated from the primary cooling water 58 and the poison 60. It is filled with a heat insulating material 70 such as Kao wool (trademark).

The wall surface 52 is made of stainless steel or the like 74,
76 are opposed to each other with a predetermined gap d therebetween to form a cavity 78 that is shielded from the primary cooling water 58 and the poison 60, and asbestos or Kaowal (trademark) is provided in the cavity 78.
Etc. are filled with the heat insulating material 80.

Then, the cavity 6 in these wall surfaces 50, 52
A pressurizing pipe 80 is connected to the valves 8, 78, and nitrogen gas or the like is supplied from an external pressurizing device 82 (pressurizing pump, high-pressure tank, etc.). This gas is applied to the heat insulating material 70 (80) and the plate 64,
Cavity 68 through the gap between 66 (74, 76),
The entire cavity 78 and 78 are evenly pressurized.

The control device 84 controls the pressurizing device 82 according to the pressure of the primary cooling water (drives the pump, opens and closes the valve, etc.) to pressurize the insides of the cavities 68, 70, and the inside and outside of the cavities 68, 78 The pressures are made substantially equal to prevent the cavities 68, 78 from collapsing and expanding, and the poison tank 24 itself from deforming. For example, during steady operation of the furnace, the pressure of the primary cooling water is 13
If the pressure is 0 kg / cm ² , then the pressure in the cavities 68 and 78 is also increased to about 130 kg / cm ² . After that, when the pressure of the primary cooling water decreases, such as when shutting down the furnace, the cavities 68, 7
By recovering the gas inside 8 from the outside of the furnace through the pipe 80, the pressure inside and outside the cavities 68 and 78 is kept constant.

According to such a heat insulating structure, the heat insulating material 7
0 and 80 are used in a non-contact state with the primary cooling water 58 and the poison 60 (that is, in a state where they are not wet with water),
Sufficient heat insulation effect is obtained, for example, the primary cooling water temperature is 32
Even when the temperature is about 0 ° C., the poison can be kept at about 150 ° C.

In the above embodiment, the poison tank 24 is used.
The present invention is applied to the entire inner and outer wall surfaces 50, 52 of
It can also be applied only partially, such as only to the inner wall surface 50 where the temperature of the primary cooling water becomes particularly high.

[0021]

As described above, according to the present invention, the wall surface of the poison tank is made into a double structure to form a cavity, and the cavity is filled with the heat insulating material. It can be used without contact with cooling water, and a sufficient heat insulating effect can be obtained even with existing heat insulating materials. Further, since the pressure is applied to the inside of the double-structured cavity, it is possible to prevent the cavity from being crushed by the pressure of the primary cooling water and from being deformed in the poison tank.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a conventional device.

FIG. 3 is a vertical sectional view showing a heat insulating structure of a conventional poison tank.

[Explanation of symbols]

 10 SPWR (Reactor) 12 Reactor Pressure Vessel 24 Poison Tank 28 Primary Cooling Water Channel 50, 52 Wall Surface 58 Primary Cooling Water 60 Poison 68, 78 Cavity 70, 80 Insulation Material 82 Pressurizing Device (Pressurizing Means)

Claims (1)

[Claims] 1. An integrated pressurized water reactor in which a reactor pressure vessel is provided with a poison tank filled with poison for stopping the reactor, and a primary cooling water passage is formed around the poison tank. The wall surface contacting with the primary cooling water has a double structure, and a cavity isolated from the poison and the primary cooling water is formed between the walls of the double structure, and a heat insulating material is filled in the cavity. In addition, an integrated pressurized water reactor in which the inside of this cavity is pressurized by a pressurizing means.