JPH0360080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to decommissioning a nuclear reactor that is considered to have completed its operational life, and more particularly to a machine for dismantling nuclear reactor structures in a consistent and safe manner.

When the reactor reaches the end of its planned operating life, after removal of the nuclear fuel and reactor cooler,
Another option is to cover the entire structure with a suitable shield, such as an earthen bun, and to ensure that the covered reactor remains so shielded at all times as a permanent "monument" or , dismantle the reactor structure and dispose of the dismantled materials in small quantities in conventional secure storage facilities, thereby restoring the reactor site to its preliminary building condition. especially,
The latter, given questions about the practicality of maintaining the shielding integrity of the entire reactor structure for the thousands of years required before biologically dangerous amounts of radioactivity decay. policy is preferred.

To relate the present invention, a reactor core including a reducer and a fuel element which can be loaded and removed by a refueling machine, and a reactor core about which the reactor core is heated by circulation through the core. A conventional gas-cooled, graphite-moderated nuclear reactor that has a heat exchanger inside the pressure vessel that extracts heat from the cooled cooler and uses it to generate electricity using, for example, steam and a turbine. I decided to think about it. Assume that when such a reactor completes its operational life, a decision is made to dismantle the reactor and restore the site. After successful removal of the fuel elements and removal of cooler gases, the turbine, heat exchanger, and fuel exchanger are removed and the top dome of the pressure vessel is removed to expose the reactor core with appropriate temporary shielding. It is considered acceptable from a safety perspective to adopt conventional dismantling techniques. In order to dismantle and remove the pressure vessel, and to extract and transport the graphite reducer (in the form of separate blocks) to a disposal facility, a machine is required to perform these operations safely and quickly. Ru.
It is therefore an object of the invention to provide such a machine.

According to the invention, a machine for dismantling and removing nuclear reactor structures and/or components irradiated during operation of a nuclear reactor and transporting them to a disposal facility comprises:
a gantry, a device for installing the gantry in a rigid part of a nuclear reactor that has not yet been dismantled, a carriage movable on or around the gantry, and a movable or non-movable mounted on the carriage; a manipulator movably mounted on the mast and capable of supporting and manipulating various tools for dismantling the reactor structure and/or components; and a hoisting device for removing and transporting dismantled reactor structures and/or components, with or without connection with said manipulator, and having all functions of said machine. is characterized by being remotely controlled. The hoist device may be movable along a diametrically or radially provided beam that is rotatable about the centerline of the reactor vessel.
The hoist device can be transferred to another beam, either fixed or rotatable.

Alternatively, the hoist device may be rotatably mounted on the mast and also movable radially relative to the mast. The mast is a single rigid structure, and the carriage should be able to move to raise and lower the mast.
Alternatively, the mast may be made from multiple sections, and the height of the mast may be varied by adding or subtracting sections or by expanding or contracting.

An example of the structure of a machine according to the invention will now be described with reference to the accompanying drawings. The same reference numerals in the figures indicate the same parts.

Referring first to Figures 1 and 2, these figures depict a gas turbine known as a Windscale Advanced Gas Cooled Reactor (WAGR), which has now reached the end of its service life and is to be dismantled. cooling,
1 schematically depicts a graphite-moderated nuclear reactor. The reactor core, including passages for the graphite moderator and fuel elements, as well as other internals such as a core support (not shown), a thermal box 1 and a refueling standpipe 2, is housed in a pressure vessel 3; Pressure vessel upper dome and standpipe 2
The upper part of is shown removed. The volume occupied by the upper dome is intended to be used for a dismantling, unloading and conveying machine, such as one of those described below and hereinafter referred to as a "handling machine". The reactor also has four heat exchanger housings 4, from which the heat exchangers are disassembled and removed using conventional equipment with shielding measures. This is because these structures have radioactivity levels that would permit such operations. building 4
(when emptied) is used as a temporary warehouse 5 for the dismantled materials, in which the sorting and selection for packaging takes place in a connecting building 6, where they are disposed of in bulk. Possible small materials are dropped into a waste container 7 below the temporary storage 5. The outer containment vessel 8 of the reactor is retained and helps maintain its integrity during demolition and related operations. The packaging building 6 is located outside the containment vessel 8 and communicates with it via an airlock (not shown).

The refueling floor level is indicated at 9 in FIG. 1 and includes a rail 10 on which the reactor's refueling machine (which has already been removed) runs.

3 to 5 show a nuclear reactor with a handling machine 11 in place. The handling machine 11 consists of a gantry 12 having wheels 13 that run on rails 10, and a carriage 14 that can rotate relative to the gantry 12 on rails 15 on this gantry 12 (particularly as shown in FIG. 4). and Figure 5). The carriage 14 is the same as the carriage 1.
A mast 16 is supported on a platform 14' linearly movable on
It can be lengthened or shortened. At the lower end of the mast 16 there is provided a manipulator 17 which can be moved both angularly and linearly relative to the mast for cutting and similar operations to dismantle the pressure vessel 3 and its contents prior to transport for packaging. The tool 18 can be supported. The mast 16 can be lengthened or shortened by adding or removing separate sections with suitable fastening means (not shown) of conventional type.

A ring gutter 19 supported by the concrete structure 20 of the reactor provides a trajectory for rotating the rotating beam 21 about the centerline of the vessel into an angular position to align with the fixed beams 22,23. The beam 22 is an intermediate beam between the beam 21 and another rotating beam 24, which can rotate around the center line of the heat exchanger housing 4, which is used as a temporary storage 5. . The beam 23 is a fixed beam extending into another heat exchanger housing 4, designated 25, which is used as a maintenance cell. For example, beams 21, 22, 23, 24
Two hoists 2 that can move along
6, 27, the hoist 26 normally operates above the container 3 and can be moved into the cell 25, and the hoist 27 is normally located on the rotating beam 24 above the warehouse 5. , it is possible to move from beam 24 via beam 22 to beam 21 or vice versa in order to convey material between the area of containers 3 and warehouse 5. Another fixed beam 2
8, the beam 24 can be aligned with this fixed beam, and the fixed beam 28 extends between the warehouse 5 and the other housing of the empty heat exchanger housing 4. This housing is designated 29 and is used as a temporary waste storage chamber. Hoist 27 moves from beam 24 to beam 28
It can be run in the opposite direction. A remote control mechanism is provided (not shown) to control and rotate the beam 2 and to move and operate the hoists 26, 27.

Manipulator 7 and tool 8 are used to cut the pressure vessel material into manageable pieces. The hoist 26 also has a conventional gripping structure at the end of the hoist cable, i.e. possibly a magnetic lifting device, to transport the pieces of material when cut into the warehouse 5 and hence into the packaging building 6 or into a temporary storage area. 29. Additionally, the hoist 26 is used to pick up the disassembled reducer block pieces and transport them to 5, 6 or 29.

In order to provide the gantry with short-term access to the upper area occupied by the carriage 14 and these components and to avoid unduly exposing these components to radiation from the container 3 and its internal contents. A rotary shield 30 with an eccentrically arranged removable shield disc 31 is provided to bridge the ring garter 20 (see FIGS. 3 and 4), and the mast 6 is connected to the disc 31. 31
When the shield 3 is removed, the shield 3 is rotated appropriately.
0 and the hoist 26 can be operated. FIG. 5 shows the mast in an extended state with the manipulator 7 and the tool 8 in a position to attack the material in the container 3, and FIG. 3 shows the mast 6 and the manipulator 7 in a retracted state.
and tool 8 are shown.

In the variant construction shown in FIGS. 6, 7 and 8, the handling machine 11' has a gantry 12 similar to the gantry 12 of the construction of FIGS. It is equipped with wheels 13 that can run on rails 10 existing on the loading surface 9. A carriage 32 is provided in the gantry 12 so as to be movable laterally. The carriage 32 is provided with a mast 6 similar to the mast 6 of the structure shown in FIGS. 3 to 5;
As in the structure shown in the figure, a manipulator 7 capable of holding a tool 8 is provided.

The main differences from the structures in Figures 3 to 5 are as follows:
The collar 34, which can be rotated on the mast 6, has a beam 3
3 are provided in the radial direction. Beam 33 can be rotated by remote control of collar 34 and aligned with intermediate beam 22 or with fixed beam 23, similar to beam 21 in the structure of FIGS. 3-5. , However, in this example, only alternate matching is possible, and simultaneous matching is not possible.
As in the structure of FIGS. 3 to 5, there is a rotating beam 24 and a fixed beam 28, and a hoist 27 operates between the container space 3 and the warehouse 5 or storage room 29.

Hoist 26 operates on beam 33 and can be moved onto beam 23 to operate within maintenance cell 25 or via beam 22 onto beam 24 to operate within cell 5. can be moved to. As in the construction of FIGS. 3-5, the mast 6 can be lengthened or shortened by adding or subtracting sections.

The structure shown in FIGS. 9 and 10 is a handling machine 11 that combines the structure of the rotating beam 21 shown in FIGS. 3 to 5 with the gantry 12 and lateral movement carriage 32 of the structure shown in FIGS. ”
However, in this handling machine, a telescoping mast 35 is mounted on a platform 36 on a carriage 32 and has a hoist 37 and a device schematically shown as a cable 38 for controlling the telescoping of a section 39 of the mast 35. .

In a variant not shown, the rotating beam 21 of the structure of FIGS. 3 to 5 is rigidly suspended from the rotating carriage 14 of the structure instead of being mounted on a separate ring girder 19 of the reactor building. , by constant rotation of the carriage 14 on the gantry 12, and transmits the load of the beam 21 to the rail 10 via the wheels 13 of the gantry 12.

In other variants not shown, the mast may be of rigid construction and a manipulator mounted on the mast may be provided with remotely operable means for raising and lowering the carriage relative to the gantry. and the height of the tool can be varied, and its height is fixed by mounting it on a rail.

If desired, the manipulator may be mounted on a platform that can be raised and lowered.

Suitable biological shields may be installed when and where necessary. For example, shields may be installed as floor-mounted retractable shields, on the gantry itself, and for maintenance cells below the gantry.

[Brief explanation of drawings]

Figure 1 is a cross-sectional side view of the reactor; Figure 2 is a plan view of the reactor being dismantled using one of the machines shown in Figures 3 to 10;
4 is a plan view, FIG. 5 is a perspective view of one structure of the machine in the operating state, FIG. 6 is a side view, FIG. 7 is a plan view, and FIG. 8 is the machine in the operating state. FIG. 9 is a perspective view of another structure, FIG. 9 is a side view, and FIG. 10 is a plan view of a modified example. 11...handling machine, 12...gantry, 14...
...carriage, 16...mast, 17...manipulator, 18...tool, 26, 27...hoist.

Claims (1)

[Claims] 1. A machine for dismantling and removing nuclear reactor structures and/or components irradiated during operation of a nuclear reactor and transporting them to a disposal facility, which includes a gantry and a rigid A device for installing a gantry in an undismantled part, a carriage movable on or around the gantry, a mast movably or non-movably mounted on the carriage, and movably mounted on the mast. a manipulator provided and capable of supporting and operating various tools for dismantling said nuclear reactor structure and/or components; a movable hoist for removing and transporting dismantled nuclear reactor structures and/or components, characterized in that all functions are remotely controlled. 2. The hoist device according to claim 1, wherein the hoist device is movable along a beam provided diametrically or radially so as to be rotatable about the center line of the reactor vessel. machine. 3. Machine according to claim 2, characterized in that the hoist device can be conveyed in a linear movement to another fixed or rotatable beam. 4. A machine according to any one of claims 1 to 3, wherein the hoisting device comprises one or more hoists which can be operated and moved separately. 5. A machine according to claim 1 or claim 4, wherein the hoist device is attached to the mast for both rotational and radial movement relative to the mast. 6. The mast is a rigid structure, and the carriage is movable vertically relative to the gantry to raise and lower the mast.
A machine according to any one of paragraphs 1 to 5. 7. A machine according to any one of claims 1 to 5, wherein the mast is made of several parts, which parts are added to or taken from the mast so as to receive the height of the mast. 8. Claim 1, wherein the mast is telescopic and a device for telescopically extending and retracting the mast is provided to provide the required height.
A machine according to any one of paragraphs 1 to 5.