GB2215902A - Radioactive material management - Google Patents

Description

TITLE Method and Arrangement for Radioactive Material Management The invention concerns a method and arrangement, with the aim of radiological and environmental protection, for continuous management of waste radioactive material or other radioactive material, particularly with high activity and contamination, such as is produced in nuclear power stations, nuclear plants, and plants using nuclides.

For radioactive waste treatment and conditioning, radio logical protection must be guaranteed by a system of hermetic enclosures, shieldings and remote control devices, with a pressure gradient from an operative zone to a processing zone.

On the whole, these demands are met only by stationary hot cells which require much expense for construction and equipment. Technological processing is preferably divided into individual process stages and accomplished by apparatus appropriate for the cells or remote control. In general, there are good possibilities for visual and remote control access and favourable conditions for flexible process design. An exchange of complexes and parts of the equipment is possible in the case of a change of technologies. Process stages which produce detrimental substances or secondary waste are localised by appropriate measures in order to minimise air and apparatus contamination falsifying, for instance, activity measurement by foreign radiation and increasing the expense of decontamination and maintenance.Radioactive constructional elements or waste conditioned in waste canisters are introduced by process locks or removed in transport containers and transported to ultimate storage. If the transport container is provided with but one load/unload opening, the waste canister must be transferred to an additional intermediary container to be transported to the emplacement and unloaded.

An alternative to the use of hot cells is treatment by shielded equipment. The equipment for treatment follow waste-part oriented concepts (DD-WP 222 997) and requires a transfer of the individual devices, or load/unload operations and transfer of the treated radioactive waste for their realisation. Viewing opportunities and possibilities for access to the mechanised or partly automated process are limited or even excluded. Devices for charging and management are transportable, flexible and connectable. Increased accuracy demands are made on joining parts. Inner contamination of the apparatus, as well as the places of coupling, increases the expense for decontamination and maintenance.

Advantages include the reduction of constructional efforts for radiologically safe construction and the flexible application of the equipment.

The invention aims at complex continuous management of waste radioactive material or other radioactive material, particularly with high activity and contamination, from the producer to the place of ultimate disposal, without employing hot cells or recharging the radioactive material between process stages, in accordance with corresponding demands.

The invention is to ensure, by means of a method and an arrangement, the complex, continuous, radiologically and environmentally safe waste management in nuclear power stations, nuclear plants, or plants of nuclide application, particularly relating to radioactive material with high activity and/or contamination, which demand shall be met by the transition of the radioactive material to a state suitable for transport and ultimate disposal without hot cells or transfer between the individual process stages up to emplacement or ultimate disposal.

According to the invention this demand is met by the use of a transportable container with a pivotable radiation-proof closure of the radioactive waste load unit which is centrally and vertically arrangable in a charging tube. Thus, continuous and independent of the direction of load/unload operations, as well as radiologically and environmentally safe enclosure of the radioactive material are ensured without additional sealing devices for radiological or contamination protection. Contamination-free loading of the waste canister without losses from preceding waste-part oriented conditioning apparatus is achieved by overlapping of the lower unloading opening and tight pressing of the upper brink of the waste canister by means of a vertically transportable lift device.Under such preconditions, only the apparatus transferring and accepting radioactive substances must be provided with radiation-proof closures. Subsequently used apparatus employed together with the transportable container do not require such closures.

Thus it becomes possible to couple technologically interchangeable apparatus to the transport container under normal inactive conditions. Furthermore, some technological stages (such as decontamination, handling and storage processes) can partly be omitted or reduced.

The process is preferably mechanised or partially automated and requires coupling conditions compatible with each other and elements for the connection of the components of the whole arrangement. Preceding wastepart oriented conditioning apparatus containing the radioactive part to be decomposed or radioactive waste consists of functionally independent, surrounding shielded coupling devices. The whole treating apparatus for mechanical or thermic separation, re-melting or laser cutting may be integrated within a cylindrical, pivoted radiation-proof closure. At the periphery of the closure, viewing means for observation of the inner space may be arranged at the shielding segment.

During the coupled state of the apparatus, loose or fragmentary material may be directly loaded to the waste canister while the level is observed by visual observation means; then the waste canister may be radiation-proof sealed and the apparatus decoupled.

Technological apparatus without anti-contamination protection may be coupled to the container for the purpose of conditioning of the radioactive material by hermetic sealing, and temperature, activity, and nuclide determination, during which operation joining parts, sensors and functional groups may be added.

The hermetically sealed, contamination-free and radiologically-defined waste canister may be transported under the shielding of the transport container and for emplacement or ultimate disposal set on a radiation-proof closure after which it may be definitely emplaced or disposed of by a lifting device with a claw which is coupled to the transport container.

The system of waste management can be adapted to the needs of the user by suitable shielding and/or absorbing materials in accordance with activity and nuclides present, various degrees of radiological protection, and various dimensions of the waste canister so that the weight of the transport container may be brought in a satisfactory proportion to the weight of the radioactive material.

The advantages of the invention consist in the possibility of the realisation of a closed technological process and arrangement of waste management, from waste treatment to ultimate disposal, with transportable, radiologically and environmentally safe equipment with low need for operation and maintenance which employs interchangeable apparatus connectable under inactive conditions.

The whole complex of apparatus, as well as the apparatus needed for individual stages of waste management, may be transferable in transcontainers.

The expense for construction and equipment needed for hot cells is avoided, as well as expensive transfer processes.

The radiation-proof and contamination-free enclosure of the unilaterally open collection container or the hermetically sealed waste canister during all process stages and manipulations of the handling and storage process allows simple coupling of apparatus in the process as well as the arrangement of apparatus for control and media supply. The function-oriented or position-oriented supply of the parts to be joined in the process of sealing of the waste canister can be carried out reliably and at low expense under inactive operation conditions.

This is advantageous for the comminution by mechanical or thermic cutting, as well as by re-melting, the conditioning by frictional, positive or material joining, weight, temperature, activity and nuclide determination of the waste canister, and computerassisted registration, input/output control and detection of internal activity. Furthermore, the object-oriented calibration of the original radiation measurement apparatus becomes realisable without any influence of foreign radiation and contamination.

In accordance with the demands of the process, special devices for monitoring (telecamera, periscope.

radiation-proof window, light guide), the taking of samples from the collection container, densification of loose material, or contamination control by wipe test on the waste canister can selectively be coupled to the transport container.

The transport container may be designed in such a way that treatment and transfer processes, as well as the transport in public traffic to emplacement for activity reduction or to ultimate disposal can be accomplished according to the demands by available means of road or rail transport.

The defined emplacement of the waste canister may be accomplished by the coupling of a lifting device to the canister or by free spoiling directly from the transport container to the cavity of emplacement or ultimate disposal. Furthermore, inactive shielding/sealing plugs of the same dimensions as the waste canister can be handled with the same apparatus.

The technology-and-apparatus-oriented continuous waste management arrangement, the constituents of which are adapted to each other, can be divided into any technological systems/sections of waste management and adapted to various coupling conditions of nuclear plants or nuclide-using plants so that the use of the transport and ultimate disposal arrangement for high-activity substances or waste will be ensured for uniform central administration and ultimate disposal.

Due to the contamination-free treatment and conditioning process, the expense for decontamination and, thus, the secondary radioactive waste during maintenance will be small and controllable under normal operation conditions.

In case of irregularities of the process or disturbances the radioactive material remains inside the shielded apparatus and can be localised in accordance with environmental demands by external actions manually effected at the transport container.

The technological apparatus may be designed with regard to maintenance so that defunct constructional elements/working units can be changed in accordance with radiological safety demands without hot cells and subjected to waste management with the same arrangement.

By way of example preferred embodiments of the invention will now be described with reference to the accompanying diagrammatic drawings, wherein: Figure 1 is a section of a transport container with a pivotable radiation-proof sealing closure, Figure 2 is a section of an apparatus with integrated waste-part oriented treatment device, Figure 3 is a section of a transport container with pivotable insert;; Figure 4 is a view partly in section of a lifting device for a waste canister, Figure 5 is a section of a lifting device with claw for a waste canister, Figure 6 is a section of an apparatus showing a unilaterally open charging tube, Figure 7 is a section of an apparatus showing a continuous charging tube, Figure 8 is an arrangement of conditioning apparatus, shown in section, for radioactive waste collection and treatment, Figure 9 is an arrangement of apparatus shown in section, for radioactive waste conditioning, and Figure 10 is an arrangement of apparatus, shown in section, for emplacement of a waste canister.

In Figure 1, a transport container 1 is shown in radiation-proof and transportable state with affixed sealing caps 12.

In Figure 2, an apparatus 3 with pivotable radiation-proof closure and integrated waste-part oriented treatment device, as well as visual observation means, is shown which can be coupled to transport container 1 or 2.

In Figure 3, a transport container 2 with pivotable insert is shown which is used for the acceptance of a waste canister 11 with sealing caps 13 in radiation-proof and transportable state.

In Figure 4, a lifting device 4 for vertical lifting and lowering as well as for weighing the waste canister 11 is shown which can be coupled to transport container 1 or 2.

In Figure 5 a lifting device 5 with claw for vertical lifting and lowering of the waste canister 11 is shown which can be coupled to transport containers 1 or 2.

In Figure 6, a unilaterally open apparatus 6 is shown which can be coupled to the transport container 1 or 2.

In Figure 7, an apparatus 7 with a continuous charging tube is shown.

In Figure 8, an arrangement of apparatus used for bringing radioactive parts/waste 10 into a transportable state suitable for ultimate disposal is shown in operation, The transport container 1 with a unilaterally open collection/waste canister 11 is so arranged on lif-ting device 4 that unload opening 17 of the attached apparatus 3 is overlapped due to tight pressing of the collection/waste canister 11 by the lifting device 4.

The radioactive part/waste 10 is by the claw of the lifting device of the apparatus 3 discontinuously supplied to a device 16 in the pivotable radiation-proof closure, and the comminuted radioactive material 10 is collected in the waste canister 11. While the apparatus 3 is in its shielded state, the internal space and/or the filling level of the waste canister 11 can be visually monitored by visual observation means 30 arranged at the periphery of the radiation-proof closure 14.

In Figure 8, 15 denotes a charging tube, 18 denotes a pivotable radiation-proof closure of transport container 1, 19 denotes a charging tube in container 1, 20 denotes load/unload opening of container 1 and 28 denotes a shielding segment in closure 14.

In Figure 9, an arrangement of apparatus for conditioning radioactive waste 10 by hermetic sealing of contamination-free waste canister 11 is shown in operative condition. The position of the transport container 1 with the filled, unilaterally open waste canister 11 on the lifting device 4 corresponds to Figure 8. Instead of the apparatus 3 the apparatus 6 is attached with the sealing cap of the waste canister 11 in radiologically safe condition. Then, the waste canister 11 is vertically lifted to the joining level of the apparatus 6 and hermetically sealed. The sealed waste canister 11 is lowered back to its initial position, and the transport container 1 is sealed to be ready for transport.

In Figure 9, 21 denotes engineering means for joining the

with the waste canister 11 and 22 denotes load/unload opening of apparatus 6.

In Figure 10 an arrangement of apparatus for emplacement of waste canister 11 to emplacement cavity 9 is presented. The transport container 2 is attached to closing device 8 of the emplacement cavity 9. The lifting device 5 with claw is in radiological safe state attached to the transport container 2, and the waste canister 11 is directly lowered to the emplacement cavity 9 for storage. By means of observation means 30 arranged at the periphery of pivotable radiation-proof closure 26 of the closing device 8, the internal spaces of the preceding and subsequent apparatus 2, 9 can be visually observed.

In Figure 10, 23 denotes a pivotable insert in transport container 2, 24 denotes a charging tube in container 2, 25 denotes a load/unload opening of transport container 2, 26 denotes a radiation-proof closure for emplacement cavity, 27 denotes a charging tube in the closing device 8 and 29 denotes a shielding segment in the closure 26.

Claims (8)

1. A method for the management of waste radioactive material or other radioactive material by bringing said radioactive material into a state suitable for transport and ultimate disposal, and loading and hermetically sealing a canister for said radioactive material and determining nuclide and/or activity and weight of the said radioactive material, and transporting said radioactive material to emplacement or ultimate disposal, wherein the state of transportability and suitability for ultimate disposal of the said radioactive material is produced by means of shielded waste-part oriented interchangeable and connectable apparatus and by direct contamination-free transfer of said radioactive material without losses and under visual level monitoring to a canister therefor contained in a radiologically safe transport container suitable for safe public transport in which it will remain up to emplacement or ultimate disposal whereafter it will be attachable to sealing means for direct filling into the cavity of emplacement of ultimate disposal under visual monitoring, and for hermetically sealing and nuclide, activity and weight determination, and transfer of the said canister, shielded technological apparatus is coupled to the transport container.

2. A method according to Claim 1, wherein for hermetically sealing and nuclide, activity and weight determination, and transfer of the said canister, shielded technological apparatus is coupled to the transport container without additional contamination protection.

3. A method according to Claim 1, substantially as herein described and with reference to one or more of the accompanying drawings.

4. An arrangement for realisation of the process claimed in Claim 1, wherein there is provided a transport container which includes a pivotable radiation-proof closure and a continuous, radiologically safely sealable charging tube in which a canister for said radioactive material is arranged for vertical movement in the charging tube, an unload opening of a preceding connectable shielded conditioning apparatus is sealed by a pivotable radiation-proof closure with an integrated waste part oriented conditioning device in a charging tube and observation means at the periphery of the lastmentioned closure at a shielding segment of the closure, interchangeable and connectable apparatus being radiologically safely and in accordance with the method couplable to a transport container, and the transportable canister ready for ultimate disposal by an attached lifting device with claw is directably lowerable or freely spoilable to an emplacement or ultimate disposal cavity.

5. An arrangement according to Claim 4, wherein the transportable, hermetically salable contamination-free waste canister ready for emplacement or ultimate disposal is radiologically safely transferable by direct load/unload operation with a weight-reduced transport container with pivotable insert.

6. An arrangement according to Claim 4 or Claim 5, wherein the transport containers are type B(U) containers.

7. An arrangement according to any one of Claims 4 to 6, which is operable in dependence on activity and nuclides by the application of suitable shielding and/or neutron absorbing materials.

8. An arrangement according to Claim 4 substantially as herein described and with reference to one or more of the accompanying drawings.