GB2157061A

GB2157061A - Radioactive material handling equipment

Info

Publication number: GB2157061A
Application number: GB08408421A
Authority: GB
Inventors: Imre Istvan Barody; Denis Simon Speyer
Original assignee: Taylor Woodrow Construction Ltd
Current assignee: Taylor Woodrow Construction Ltd
Priority date: 1984-04-02
Filing date: 1984-04-02
Publication date: 1985-10-16
Also published as: GB8408421D0; GB2157061B

Abstract

Equipment for handling radioactive waste material that is contained in protective canisters (12) that are to be placed in bore holes (3) in deep water beds comprises a carrier (1) for carrying a number of such canisters in a string, the carrier being movable to and locatable with the head (2) of a bore hole. A container (8) of grout (9) is also carried by the carrier and the grout is passed through a valve (10) in the grout container into the bore hole. Winch mechanism (14) is mounted in the carrier for lowering the string of canisters into the bore hole so that the canisters become sealed in the bore hole, embedded in the grout. <IMAGE>

Description

SPECIFICATION Radioactive material handling equipment This invention relates to equipment for handling radioactive material that is waste material that is to be disposed of by burial in bore holes in deep water beds.

One possibility for disposing of radioactive waste material is to place suitable protective canisters formed in deep water beds, tbe canisters being sealed in the bore holes, thus totally isolating them from the biosphere.

According to the present invention there is provided equipment for handling radioactive waste material that is contained in protective canisters that are to be placed in bore holes in deep water beds, the equipment comprising a carrier for carrying a number of such canisters in a string and also carrying a container for grout, the carrier being movable to and locatable with the head of a bore hole; means for releasing grout from the container to enter a bore hole on the head of which the carrier is located for sealing in the bore hole a lowered string of canisters with each canister embedded in grout; and winch mechanism mounted in the carrier for lowering a string of canisters into the bore hole.The carrier can be lowered to a bore hole head from a drilling rig, a surface vessel, or from a submersible or semi-submersible vessel, the lowering equipment including an umbilical cable over which power and signals can be transmitted to and from components on the carrier as necessary. Such components can include, in addition to the winch mechanism and any prime mover associated therewith, thrusters for manoeuvring the carrier, a television camera for monitoring docking with a bore head, and a valve operable to release grout from the grout container.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing in which the single Figure is a diagrammatic side view showing radioactive waste material handling equipment located on the head of a bore hole formed in a deep water bed.

The equipment shown in the Figure consists of a carrier 1 in which other components of the equipment are mounted. The carrier 1 is an elongated cage which is upright when it is located (as shown in the Figure) on the head 2 of the bore hole 3. For manoeuvring onto the head, the carrier is provided with thrusters 4.

At the base of the carrier 1 there are locking devices 5 for automatically locking the carrier with the bore hole head 2, and transponders 6 for aiding positioning and thus correct docking. A television camera 7 is suitably mounted for monitoring docking with the well head. Also in the base of the carrier 1 there is a container 8 for grout 9, the base of this container 8 being provided with a valve 10 operable to release grout into the bore 3.

Above the container 8, centrally in the carrier 1, there is an elongate guide and support 11 for a number of canisters 12 connected to a string. This string of canisters is supported hanging from the cable 13 of a winch drive 14 having a prime mover 15. if the winch drive 14 is hydraulic the prime mover 15 will be a power pack driven by an electric motor If the winch drive 14 is hydraulic, the prime mover 15 will be a power pack driven by an electric motor. If the winch drive 14 is electric the prime mover will be an electric motor. In either case electric power is supplied to the prime mover via an umbilical (see below).

For handling radioactive waste material, protective canisters containing the material are loaded into the carrier, connected end-to-end to form the string of canisters 12. The carrier carrying the string of canisters is then lowered from a drilling rig, a surface vessel, or from a submersible or semi-submersible, until the thrusters 4 can be operated to effect docking with the head 2 of the bore hole previously formed. The connection from the carrier 1 to the rig, surface vessel or submersible or semi-submersible is via a load-carrying cable arrangement 16 which incorporates an umbilical over which signals and power can be transmitted to and from components on the carrier such as the thrusters, the television camera, the winch and the valve in the base of the grout container.

With the carrier 1 locked to the bore head 2, the valve 10 in the base of the container 8 is opened and grout 9 from the container 8 allowed to flow into the bore hole 3. The consistency of the grout is such that the canister 12 can then be lowered into the bore hole through the grout, and operation in this way ensures that each of the canisters is well-bedded in the grout. To lower the canisters, the winch is operated. Once the canisters are in position the winch cable 13 is released from the canisters and hauled back to the winch ready for the next trip to carry another load of canisters.

In the form illustrated the carrier 1 is provided with centralisers 17 for guiding the carrier 1 centrally through a moon pool.

It will be appreciated that as compared with, for example, lowering canisters by means of a pipe extending from the surface to a bore hole, the present handling equipment offers greater flexibility of operation. For example, in bad weather conditions, canister disposal operations can merely be suspended and no vulnerable equipment will be left exposed to undesirable motion. The canisters do not have to be contained in a separate pipe to support their weight while lowering, which then has to remain in the bore hole. Pipes do not have to be provided for lowering canisters and handled for every load. Less accurate station keeping is required and power requirements for lowering the equipment and canisters, and raising the equipment, is minimised. A further minimisation in power requirements could be obtained by providing buoyancy for the carrier.

Should the lowering cable arrangement 16 fail, the carrier 1 will protect the canisters from damage as the equipment and the canisters drop to the sea bed, the canisters will remain together, and the carrier with the canisters should be relatively easy to locate and recover.

Maintenance work can be carried out at the surface.

Time and expense is saved by providing that grout is placed along with the canisters, and no separate trips for grouting are required.

Claims

1. Equipment for handling radioactive waste material that is contained in protective canisters that are to be placed in bore holes in deep water beds, the equipment comprising a carrier for carrying a number of such canisters in a string and also carrying a container for grout, the carrier being movable to and locatable with the head of a bore hole; means for releasing grout from the container to enter a bore hole on the head of which the carrier is located for sealing in the bore hole a lowered string of canisters into the bore hole.

2. Handling equipment as claimed in claim 1, wherein said means for releasing grout comprises a valve through which the grout passes to enter the bore hole, and through which said string of canisters also passes to enter the bore hole.

3. Handling equipment as claimed in claim 1 or 2, wherein thrusters for manoeuvring the carrier are mounted on the carrier.

4. Handling equipment as claimed in claim 1, 2 or 3, wherein a prime mover for the winch mechanism is mounted on the carrier,

5. Equipment for handling radioactive waste material, substantially as hereinbefore described with reference to the accompanying drawing.