JPH07113896A - Reactor service platform - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to carry out work in a reactor in a state of being water-filled in the reactor well from the viewpoint of reducing exposure, and in parallel with other work on the operating floor. To provide a furnace service platform. [Structure] Reactor service platform according to the present invention
Reference numeral 10 denotes a circular rail 11 that is detachably installed on a step portion 2a for installing a reactor well cover inside a reactor well 2 formed in an upper portion of a reactor pressure vessel 3, and an atom traveling on the circular rail 11. The rotary well 12 has a diameter smaller than the inner diameter of the furnace well 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor service platform for operating a boiling water nuclear reactor (hereinafter referred to as "BWR") from the operating floor to the entire area inside the nuclear reactor.

[0002]

2. Description of the Related Art Generally, BWR internal work can be roughly divided into routine work such as fuel replacement and fuel transfer scheduled for each periodical inspection, and non-routine work such as internal work. Routine work and non-routine work will be described with reference to FIGS.

Routine work is generally carried out by a fuel exchanger 31 that runs on rails installed on the operating floor 1, and fuel is taken in and out of a fuel storage rack 33 in a fuel storage pool 32. .

The out-of-routine work is carried out on the service platform 6 installed on the RPV flange surface 4 above the reactor pressure vessel (hereinafter referred to as RPV) 3 after draining the water from the reactor well 2. This service platform 6 swivels on a circular rail 7 pre-installed on the RPV flange face 4. Moreover, it swivels in the inner space formed by the RPV stud bolts 5 standing on the RPV flange surface 4. Operations from this service platform 6 include the bottom of the reactor well 2 and the reactor pressure vessel 3.
There was a high possibility that workers would be exposed to radiation from the plant.

On the other hand, from the viewpoint of reducing radiation exposure, out-of-routine work such as in-reactor work may be performed from above the fuel exchanger 31 on the operating floor 1. In this case, there is a disadvantage that the in-reactor work and the work such as fuel transfer in the fuel pool 32 installed on the operating floor 1 cannot be performed at the same time.

[0006]

When performing non-routine work from the service platform 6, radioactive substances adhering to the fuel surface peel off during fuel refilling work and accumulate at the bottom of the reactor well 1 for high doses. And it becomes a highly polluted area, and the radiation dose of workers increases. Therefore, in terms of radiation control, there is a problem in that the work of masking the entire surface is required and the work efficiency is reduced.

On the other hand, when performing out-of-routine work from the refueling machine 31, there is a problem that work in the fuel storage pool 32 such as fuel inspection and remodeling work in the reactor cannot be performed in parallel. Further, there is also a drawback that a dryer, a separator, etc. (not shown) in the equipment storage pool 34 installed on the operating floor 1 cannot be carried out in parallel.

The present invention has been made in consideration of the above points, and is carried out in a state where the reactor well 2 is filled with water from the viewpoint of reducing exposure, and in parallel with other work on the operating floor 1. The purpose of the present invention is to provide a nuclear reactor service platform that enables

[0009]

In order to achieve the above object, in the present invention, it is detachably installed on a step portion for installing a reactor well cover inside a reactor well formed in an upper part of a reactor pressure vessel. And a rotating pedestal having a diameter smaller than the inner diameter of the reactor well running on the circular rail.

[0010]

With this configuration, the reactor service platform can run on the circular rail installed on the stepped portion for installing the reactor cover inside the reactor well. For this reason, the worker does not descend to the bottom of the reactor well corresponding to the height of the RPV flange surface, and is water-filled up to an intermediate height of the reactor well,
It is possible to perform routine work such as fuel transfer work in parallel with non-routine work such as in-furnace work. Through such work, it is possible to reduce the exposure of the worker and the period of the periodic inspection.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, a reactor service platform 10 includes a circular rail 11 laid on a stepped portion 2a for installing a reactor cover in a reactor well 2 and a rotary base 12 which can turn 360 ° or more on the circular rail 11. Composed of. The rotary mount 12 is swung by a drive device 14. The drive unit 14 is composed of an electric motor and a speed reducer 14a, and wheels 14b that are interlocked with the electric motor and the speed reducer 14a. A work floor 15 is installed at the center bottom of the rotary base 12. An upper pedestal 13 is installed on the work floor 15. At the top of the upper mount 13,
A monorail 16 is attached, and a hoist 17 having an electric winch 17a and an air hose reel 17b is attached thereto.

In FIG. 2, a rectangular opening 18 is provided in the center of the work floor 15 of the nuclear reactor service platform 10. A handrail 19 is installed around the outside of the opening 18 to prevent the worker from falling, and on the outside of the handrail 19, an upper mount is installed.
Thirteen pillars 13a are erected.

In FIG. 3, an auxiliary wheel 20 is rotatably attached to the drive unit 14 of the nuclear reactor service platform 10 in addition to the wheel 14b. This auxiliary wheel 20 rotates in contact with the guide plate 11a of the circular rail 11 and is used for preventing displacement of the nuclear reactor service platform 10. The shape of the circular rail 11 is provided with a guide plate 11a so that the circular rail 11 turns while contacting the auxiliary wheel 20. Further, in order for a worker to move up and down from the operating floor 1 to the work floor 15, a staircase 21 is provided above the inside of the reactor well 2 and a ladder 22 is provided inside the reactor service platform 10.

Next, the operation of this embodiment having such a configuration will be described. First, the circular rail 11 is laid on the reactor cover installation step 2a in the reactor well 2.
A rotary mount 12 is mounted on the circular rail 11 thus installed. The service rope (not shown) in the reactor is attached to the wire rope tip of the hoist 17 installed on the monorail 16 above the upper base 13, and the opening of the work floor 15 is installed.
It hangs from 18. The operation panel (not shown) of the rotary mount 12 is operated to swivel, and the wire rope of the hoist 17 attached to the monorail 16 is moved up and down, left and right to
Position 12 With such an operation method,
The hoist 17 can be aligned with any position within V3. Next, as shown in FIG. 4, the work can be performed in a state 2b in which the reactor well 2 is water-filled to an intermediate height. In addition, the height of the rotary base 12 of the reactor service platform 10 is set to the operating floor 1
It is lower than the handrail 1a erected on the. Therefore, the refueling machine 31 traveling on the operating floor 1
The handrail 1a and the rotary mount 12 can be straddled. In this way, routine non-routine work such as in-reactor work from the nuclear reactor service platform 10 and routine work such as fuel transfer by the fuel exchanger 31 can be carried out in parallel. The operation from the refueling machine 31 is performed by the fuel rack 33 installed in the fuel storage pool 32 provided beside the reactor well 2.
Fuel entry and exit to and from the equipment storage pool 34 may be illustrated.

Further, by installing a pool gate 35 in the fuel storage pool 32 and a pool gate 36 in the equipment storage pool 34, water can be filled up to the intermediate height 2b of the reactor well 2.

As described above, according to the present embodiment, it is possible to perform non-routine work such as in-reactor work in the reactor from above the reactor service platform 10 while the reactor well 2 is filled with water. It is possible to improve the work efficiency by reducing the radiation exposure of workers and wearing protective equipment for radiation control. Further, by rotatably installing the reactor service platform 10 in the reactor well 2, the routine work from the refueling machine 31 and the non-routine work from the reactor service platform 10 are performed in parallel. It is possible, and the regular inspection period can be shortened significantly.

[0017]

As described above, according to the reactor service platform of the present invention, it is possible to work in a state in which the reactor well is filled with water, and the work from the refueling machine can be performed in parallel. Therefore, it is possible to reduce the radiation exposure of workers, improve the work efficiency, and significantly shorten the regular inspection period.

[Brief description of drawings]

FIG. 1 is a bird's eye view showing a nuclear reactor service platform according to an embodiment of the present invention.

2 is a top view of the nuclear reactor service platform shown in FIG.

3 is a side view of the reactor service platform shown in FIG.

FIG. 4 is a schematic vertical cross-sectional view of the upper part of the reactor building on which the reactor service platform shown in FIG. 1 is placed.

FIG. 5 is a schematic vertical sectional view of an upper portion of a reactor building on which a conventional service platform is mounted.

FIG. 6 is a schematic vertical sectional view of a reactor well in which a conventional service platform is installed.

FIG. 7 is a top view showing a conventional service platform.

FIG. 8 is a side view showing a conventional service platform.

[Explanation of symbols]

2 ... Reactor well, 2a ... Step portion for installing reactor well cover, 3 ... Reactor pressure vessel, 10 ... Reactor service platform, 11 ... Circular rail, 12 ... Rotating mount, 13 ... Upper mount, 14 ... Driving device , 14a ... Electric motor and speed reducer, 17 ... Hoist (hoisting machine), 18 ... Working opening.

Claims (3)

[Claims] 1. A circular rail detachably installed on a step portion for installing a reactor well cover inside a reactor well formed in an upper part of a reactor pressure vessel, and the reactor well running on the circular rail. And a rotary mount having a diameter smaller than the inner diameter of the reactor service platform. 2. The rotating platform is provided with a working platform having a working opening, and a hoisting machine that travels through the upper platform is provided on an upper part of the working platform. Reactor service platform. 3. The nuclear reactor service platform according to claim 1, wherein the rotary gantry is provided with a drive device that is rotated by an electric motor.