JPH08248173A - Reactor pressure vessel top lid cooling method and apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] The upper lid of the reactor pressure vessel is quickly and effectively cooled to shorten the waiting time after the reactor shutdown.
Improve the workability of installing and removing cooling equipment to simplify the preparatory work. [Configuration] A through hole is made in the heat insulating material that covers the surface of the upper lid of the reactor pressure vessel, and cooling air is sent through the through hole to generate an air flow in the gap between the upper lid and the heat insulating material. Then, the surface of the upper lid is forcibly cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cooling a reactor pressure vessel upper lid, and more particularly, to improving workability when removing the reactor pressure vessel upper lid in periodical inspection of the reactor. It is a thing.

[0002]

2. Description of the Related Art When removing the upper lid of a reactor pressure vessel in connection with periodical inspection of the reactor, the operation of the reactor is stopped and the reactor pressure vessel and its upper lid are cooled to a low temperature state. It will be done after waiting for.

[0003]

However, after the nuclear reactor is shut down, nuclear decay heat is continuously released from the core, and the space between the upper lid and the reactor containment vessel is provided around the upper lid of the reactor pressure vessel. Since the heat insulating material (heat insulating material) for suppressing the heat transfer of the upper lid is arranged, the temperature of the upper lid does not easily drop, and it is unavoidable to wait for, for example, ten or more hours until the temperature at which the work for removing the upper lid can be started. Has been done.

The present invention has been made in view of the above circumstances, and achieves the following objects. To quickly and effectively cool the upper lid of the reactor pressure vessel,
Shorten the waiting time after the reactor shutdown. Improve the workability of installing and removing cooling equipment to simplify the preparatory work.

[0005]

Means for Solving the Problems Before removing the upper lid of the reactor pressure vessel, in order to cool the upper lid from the surface, a through hole is formed in a portion of a heat insulating material covering the surface of the upper lid, and the through hole is formed. Cooling air is sent in via air to generate an air flow in the gap between the upper lid and the heat insulating material to cool the surface of the upper lid, and the air whose temperature has risen due to heat exchange with the nozzles and piping arranged on the upper lid. It is released through the gap with the heat insulating material. During the reactor operation, the through hole opened in the heat insulating material is kept closed.When cooling the upper lid, remove the closed part and attach the cooling fan to the support frame outside the through hole. It is desirable that the operation is forced cooling in which cooling air is generated. If a pressurized air source is provided inside or near the reactor containment vessel, in addition to the operation of the cooling fan, pressurized air is passed through the through hole to the gap between the upper lid and the heat insulating material. It is effective to use sending technology together.

[0006]

In the operating state of the reactor, the upper lid is covered with the heat insulating material to suppress the heat radiation and prevent the reactor containment vessel surrounding the upper lid from being heated. When removing the upper lid of the reactor pressure vessel in connection with the periodic inspection of the reactor, etc., the cooling air is sent to the gap between the upper lid and the heat insulating material by operating the cooling fan or connecting to the pressurized air source. Cool the top lid from the surface. In this case, the air whose temperature has risen due to heat exchange with the upper lid is discharged from above the upper lid and the heat insulating material, and a new cooling air intake property is secured. After the top lid is cooled, the work of removing the top lid is performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for cooling a reactor pressure vessel upper lid and an apparatus therefor according to the present invention will be described below with reference to FIGS. In the figure, reference numeral 1 is a reactor pressure vessel,
Reference numeral 2 is a reactor containment vessel, 3 is a heat insulating material, 4 is a support frame, and 5 is a cooling device.

The upper lid 11 and the body 12 of the reactor pressure vessel 1 are divided at a flange 13 portion, and a bulkhead 17 is integrally provided with a mounting bracket 14 for supporting the support frame 4. An appropriate number of nozzles 15 for attaching pipes for connecting to the outside are arranged on the top of the upper lid 11 or the like. The flange 13 has a stud bolt 16 for connecting the upper lid 11 and the body portion 12.
Are arranged.

A top head 21 is detachably attached to the reactor containment vessel 2, and the top head 2 is
1 is removed at the time of assembling the reactor, at the time of periodic inspection, or at the time of refueling to open the upper space of the reactor pressure vessel 1.

As shown in FIGS. 1 and 2, the heat insulating material 3 is arranged such that the surface of the upper lid 11 is covered with a gap G inside the heat insulating material 3 supported by the supporting frame 4. A plurality of through holes 31 penetrating inward and outward are formed at a lower position of the side portion, a support frame 32 extending outward is arranged in the through holes 31, and an appropriate number of nozzles 15 are provided at an upper position. An opening 33 is formed to make the through state.

As shown in FIGS. 2 and 3, the support frame 4 is arranged so as to surround the reactor pressure vessel 1, and the weight is supported by the bulkhead 17.
The heat insulating material 3 is attached to the inner surface thereof.

The cooling device 5 is arranged to cool the upper lid 11 of the reactor pressure vessel 1, and the heat insulating material 3
And a cooling fan 51 attached to the support frame 32.
As shown in FIGS. 1 and 2, the cooling fan 51 is detachably attached to the support frame 32 with bolts or the like,
In a normal state such as during a nuclear reactor operation, the through-hole 31 is provided in a portion where the blocking heat insulating material 34 which is provided in a blocked state is removed.

A method of operating the cooling device 5 to cool the upper lid 11 of the reactor pressure vessel 1 will be described below.
During operation of the nuclear reactor, the heat insulating material 34 for closing is inserted into the through hole 31 to close the inside of the heat insulating material 3, and the upper lid 11
It is possible to prevent the heat radiation from the inside of the reactor containment vessel 2 and prevent the heating of the reactor containment vessel 2. However, when the top lid 11 is removed in connection with the periodic inspection of the reactor, the top head 21 of the reactor containment vessel 2 is removed. After that, the blocking heat insulating material 34 is removed to open the through hole 31, and the cooling device 5 is operated to forcibly cool the upper lid 11.

A cooling fan 51 is attached to the support frame 32, and the air (cooling air) outside the heat insulating material 3 is sent into the gap G between the heat insulating material 3 and the upper lid 11 via the through hole 31. As shown by the arrow in FIG. 1, an air flow is generated in the gap G to cool the surface of the upper lid 11, and the air whose temperature has risen due to heat exchange with the upper lid 11 is discharged from the opening 33 of the heat insulating material 3. To release.

By performing such forced cooling of the upper lid 11, new cooling air is sequentially introduced, and the upper lid 11 is cooled.
Cooling can be continuously performed, and the surface temperature of the upper lid 11 is rapidly lowered. After confirming that the temperature of the upper lid 11 has dropped to the optimum working temperature, the stud bolt 1
Removal work of the upper lid 11 such as removing the upper lid 11 from 6 is carried out.

[Other Embodiments] It is also possible to use the forced feeding of cooling air by the operation of the cooling fan 51 in the cooling device 5 and the supply of cooling air by jetting air from a pressurized air source as appropriate. is there. The pressurized air source may be any one arranged in advance in the vicinity of the flange 13 of the reactor pressure vessel 1, so that, for example, the inside of the reactor containment vessel 2 or the equipment of the reactor building can be used. .

[0017]

According to the reactor pressure vessel upper lid cooling method and apparatus according to the present invention, the following effects can be obtained. (1) From the through hole where the heat insulating material covering the surface of the upper lid is opened,
By sending the cooling air into the gap between the upper lid and the heat insulating material to cool the surface of the upper lid, the upper lid of the reactor pressure vessel can be quickly and effectively cooled. (2) By the above rapid cooling of the upper lid, it is possible to shorten the waiting time after the reactor is stopped when removing the upper lid, improve the work efficiency, and shorten the period required for periodic inspections and the like. (3) Since the cooling fan is attached to the support frame in the vicinity of the through hole of the heat insulating material and the cooling air is sent by its operation, the workability of attaching / detaching the cooling device can be improved and the preparation work can be simplified. it can. (4) To further effectively cool the upper lid by using the cooling air supply by jetting air from a pressurized air source as appropriate, using the equipment inside the reactor containment vessel and the reactor building. In addition, it is possible to reduce the equipment cost of the cooling device.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of a method for cooling a reactor pressure vessel upper lid and an apparatus therefor according to the present invention.

FIG. 2 is a front view showing a state where the support frame and the cooling fan of FIG. 1 are assembled, with a part of the description omitted.

3 is a plan view of the support frame of FIG. 1. FIG.

[Explanation of symbols]

 1 Reactor Pressure Vessel 2 Reactor Containment Vessel 3 Heat Insulating Material 4 Support Frame 5 Cooling Device 11 Upper Lid 12 Body 13 Flange 14 Mounting Bracket 15 Nozzle 16 Stud Bolt 17 Bulkhead 21 Tophead 31 Through Hole 32 Support Frame 33 Opening 34 Heat insulating material for blocking 51 Cooling fan G Gap

Claims (2)

[Claims] 1. A method for cooling an upper lid (11) of a reactor pressure vessel (1), comprising a heat insulating material (3) for covering a surface of the upper lid.
A through hole (31) is formed in the through hole, and cooling air is sent through the through hole to generate an air flow in a gap (G) between the upper lid and the heat insulating material to cool the surface of the upper lid. Reactor pressure vessel top lid cooling method. 2. A device for cooling the upper lid (11) of a reactor pressure vessel (1), the heat insulating material (3) covering the surface of the upper lid.
A support frame (32) arranged outside the through hole (31) opened in the above, and cooling air is sent through the through hole which is attached to the support frame and is fed into the gap (G) between the upper lid and the heat insulating material. A cooling fan (5 that generates an air flow to cool the surface of the top lid)
1) A cooling device for a reactor pressure vessel upper lid, comprising: