GB2096388A - Method and apparatus for storing radioactive and/or toxic substances - Google Patents

Abstract

In providing safe storage for toxic, especially radioactive, material which is not otherwise processable, a substantially dry mortar mix is introduced into an appropriately shielded chamber, there to be mixed with the material to be stored, sufficient water being present, or being added, to permit the mix to harden. Preferably the water used is itself toxic or radioactively contaminated. Supply means 3 is readily accessible to direct the mortar mix to continuous mixer 2 in shielded chamber 9. Appropriate conveying means are used to transport solid waste via lines 12 or 14 to mixing zone 5 and water is added if required via line 11. The mix is discharged via outlet 17 to set in drum 19. The system may be enclosed in a glove box. <IMAGE>

Description

SPECIFICATION Method and apparatus for storing radioactive and/or toxic substances The present invention relates to a method of removing and cementing radioactive and/or toxic substances, especially radioactive and/or toxic water, solutions or the like and/or comminuted radioactive and/or toxic material (e.g. shredder material), whereby these substances are embedded in a setting or hardening binding agent mixture and are poured into containers or drums.

The present invention also relates to an apparatus for cementing radioactive or toxic waste in drums, wherein the constituent parts or components of the mixture are added from various stores and the drum to be filled is detachably connected to a glove box, which accommodates at least parts of the apparatus, such as, for example, the mixing tools required to mix the individual components, or the drum to be filled is detachably connected to a hot cell with the application of the double cover technique.

There are numerous radioactive and other toxic substances which, for technical reasons, are not reprocessed, but have to be given safe intermediate or final storage. These substances are generally embedded in bitumen, cement, plastics material, concrete or other binding agents and poured into containers, such that the substances to be removed are first poured into the containers or drums and the binding agent is then added, after which the entire drum content is to be mixed by stirring. However, the risk with this process is that a considerable portion of radioactive waste substances, in particular, lies at the outer wall of the drum.Moreover, it is difficult to transfer the binding agent to a radioactivelycontaminated chamber where the containers to be filled are disposed, or, if concrete were used, a whole concrete mixer would have to operate under radioactive radiation in some circumstances, so that, after a certain length of time, this mixer is itself radioactive and has in fact to be removed at some time or other.

In nuclear power stations, radioactive water mixed with salts is particularly produced, such water especially resulting from the cooling process and not being capable of being absorbed adequately by the above-described binding agents.

Consequently, in order to obtain a product which is suitable for final storage, radioactive waste must be set generally in the waste containers, as already mentioned. This waste may be solid radioactive waste, such as, for example, scrap, building rubble or the like, or it may, however. be liquid radioactive waste, such as, for example, evaporation concentrates or sludges.

In the past, liquid radioactive waste was generally set in specific cementing systems. For this purpose, either cement is first inserted into a drum and the liquid material to be fixed or set is metered, added, then stirred with the cement in the drum, or, alternatively, the entire drum is rotated with cement and the liquid material on an appropriate device so that the cement is intimately mixed with the liquid material.

Moreover, methods are known wherein radioactive sludges or concentrates are conventionally mixed with cement and additives in an automatic mixer and then poured into drums. Solid, radioactive wastes are generally poured into drums and then inactive concrete or cement glue is poured over them. This concrete or cement glue is stirred conventionally and is also conveyed therewith.

The disadvantage with such known solutions is that the liquid radioactive substances and the dry cement have to be metered separately. This metering takes a relatively long time. Both by stirring in a drum and by rotating the drum, this drum cannot be filled to a maximum since a specific clearance space always has to be available as the stirring volume. When the solid waste is set in concrete, the volume of the drum is not fully utilised since the intermediate spaces have to be filled with inactive material.

Consequently, the present invention now seeks to mix, over as small a region as possible, the inactive added substances, such as cement and sand, and the active liquid substances, such as.

for example, evaporation concentrates or sludges, and then to pour this material either into an empty waste drum or into a waste drum which has already been filled with solid waste. The system should therefore be as small as possible and should be capable of being composed of largely conventional apparatus.

The aim, therefore, is to provide a method of the above-mentioned type, whereby the substances mentioned may be removed more satisfactorily and more effectively, i.e. even with a saving of binding agent, so that as much as possible of such material can be removed over as narrow and as concentrated an area as possible and can be stored later, and whereby, in particular, machines and machine parts, which may become radioactive, should have as small a dimension as possible.

This object is essentially achieved in that a substantially dry binding agent mixture is introduced into a chamber or the like, which is screened from radiation, is mixed there with the substance to be removed and is caused to harden.

In such a case, it is particularly advantageous for the binding agent mixture to be mixed first with radioactive and/or contaminated water and for it thereby to be prepared for hardening. The water to be removed is therefore used simultaneously for mixing, so that a substantially larger quantity of such water or of a corresponding solution may be removed simultaneously.

After being prepared and prior to setting, the mixture may be poured into a storage drum or the like. In addition to the water, the comminuted material (shredder material) may be preferably mixed with the binding agent mixture and be poured into a drum or the like. It is therefore possible to accomplish the entire mixing and preparation processes in an appropriate continuous mixer, thereby achieving a substantially more intimate and more uniform mixing result than if the substances are stirred with the binding agent in a drum intended for storage.

One embodiment of the invention of particular inventive significance may reside in an initially dry mortar mixture serving as the binding agent mixture and being conveyed into a mixing apparatus in the radioactive chamber. Mortar, plaster or the like may be prepared with a relatively large amount of water, as is wellknown, and is highly suitable for surrounding and screening solid substances. One purpose of mortar is, of course, to screen the wall layer from the atmosphere when plastering houses. A further advantage of such a mortar or plaster mixture is that the setting times may be influenced in known manner by appropriate additives, so that, for example, a setting time may be selected which is so short that there is no possibility of separation, even if relatively heavy or particularly light components are embedded.

The invention also seeks to provide a device for removing radioactive and/or toxic substances, which device permits an easy and also, in the case of removing radioactive substances, a safe mode of operation.

For achieving this object, the present invention now proposes an apparatus for cementing radioactive or toxic waste in drums, wherein the toxic waste is embedded in a setting or hardening cement mixture and is poured into a drum, wherein the mixture constituent parts or components are added from various stores and the drum to be filled is detachably connected to a glove box, which accommodates at least parts of the apparatus, or the drum to be filled is detachably connected to a hot cell with the application of the double cover technique, in which a continuous mixer is located in the glove box or in the hot cell and is provided with a housing, the continuous mixer feeding the drum with the discharge of the housing, and a conveyor is provided and is connected to the feed aperture of the continuous mixer for the delivery of the dry cement mixture, the supply line for the liquid components of the mixture being connected to the conveyor in the region of the feed aperture.

In such a case, it is particularly advantageous for the supply line for the liquid radioactive components to be connected to a storage container for liquid radioactive concentrates and for means to exist for the metering thereof. It is also advantageous for a fresh-water metering line to be connected to the supply line for the liquid radioactive concentrates or in the region of the mouth of the supply line which discharges into the continuous mixer housing.

The invention also proposes that a further worm conveyor screw housing, with its outlet aperture, be connected to the continuous mixer housing or to the worm conveyor screw housing for the dry cement mixture-viewed in the direction of conveyance-in front of the mouth of the supply lines for the liquid components and be capable of being fed with dry shredder material, and the invention also proposes that a further worm conveyor screw housing, with its outlet aperture, be connected to the same continuous mixer housing-viewed in the direction of conveyance-behind the mouth of the supply lines for the liquid components and be capable of being fed with liquid or with wet ion exchange resins.

Above ail, the novel feature of the present invention is that liquid radioactive waste may now be used for concreting over solid waste.

In many systems, for example, the radioactive waste water produced in the screw mixer may therefore be used for concreting purposes.

Consequently, the invention permits the drums to be filled with optimally radioactive waste of a liquid or solid nature. Any desirable combinations of solid and liquid radioactive waste may be produced. The consistency of the cement slurry produced may be controlled and adjusted as desired. In such a case, the entire system can be accommodated in a simple glove box in a particular advantageous manner, so that it is also suitable for small and medium throughputs of radioactive waste. Finally, the proposed system is largely composed of conventional parts, so that wide availability and a high degree of safety can be expected.

The device according to the invention is also characterised in that a continuous mixer is provided with a supply region for a binding agent mixture, preferably a building material mixture or the like, wherein a metering region is preferably screened behind the supply region and, connected thereto, the mixing region is preferably screened from the supply region on the outside surface of the device. For the removal of radioactive waste, the continuous mixer may therefore be disposed with its supply region externally of a screened chamber, but with its mixing region inside this chamber, so that only one portion of this device is exposed to the radioactive rays. In addition, the binding agent mixture is thus particularly simple and safe to supply.

A screen, especially an anti-radiation screen, may be provided especially in the metering region of the continuous mixer on the outside surface thereof, and the supply line for the substances to be removed-viewed from the supply region may be arranged behind the screen. As was usually the case hitherto, the substances to be removed are therefore mixed, in a radioactive region, with the binding agent mixtures which are conveyed to this area by the mixer itself in a simple manner.

The inlet for the substances to be removed may be disposed in the wet region of the continuous mixer. If building material mixtures are used, especially plaster or mortar mixtures, it is first necessary to mix them with water so that they may set, but before the water is admitted, the solid substances to be removed may already have been admixed. In such a case, at least one connection may be provided immediately behind the metering region for the introduction of the shredder material (sliced or chopped waste material), and the connection for the mixingwater, especially for water to be removed, for sludge or similar liquid constituent parts, may be provided behind the above-mentioned connection in the direction of conveyance. What is to be understood by sludge in such a case is also a solution of toxic or radioactive salts is correspondingly contaminated water.The removal, above all, of radioactive substances is particularly effective when a mortar or plaster mixer is used for embedding solid constituent parts, such a mixture being thereby mixed with radioactive water or sludge. This building material mixture may thus also absorb and bind a particularly large amount of contaminated water.

A worm conveyor screw may be provided within a conveyor conduit for supplying solid, preferably comminuted substances which are to be removed, which conveyor conduit angularly discharges into the continuous mixer housing transversely to the advance direction of the binding agent mixture. In such a case, the continuous mixer may extend behind its metering conduit and preferably have a worm conveyor screw or the like in a first portion of the mixing chamber, the solid substances to be removed being capable of being supplied to the region of the worm conveyor screw, and paddle mixer screws or the like may especially be provided in the region of the water or sludge supply line.

However, the paddle mixer screws may also be provided over the entire region in connection with the metering conduit of the continuous mixer.

This arrangement first of all permits the solid substances for removal to the mixed with the still dry mortar mixture, whereby, however, the mixing process is then continued further and improved in the region of the water supply line.

The continuous mixer may be disposed so high above the ground, and may preferably have such high feet or supports, that a drum or similar container for radioactive and/or toxic waste fits beneath its discharge aperture. On the whole, this produces an arrangement which is very easy to handle, whereby only one drum has to be placed beneath the said discharge aperture and then has to be removed again after it has been filled, while the continuous mixer ensures that the substances to be stored are thoroughly mixed with a binding agent, as required.In such a case, the mixing process, using a continuous mixer in accordance with the invention, is so intense that a large amount of material to be removed can accordingly be absorbed per unit of volume, and the degree of efficiency is thereby further increased in an advantageous manner by using water or sludge to be removed for the preparation of the binding agent mixture.

It may also be mentioned that the portion of the continuous mixer which is exposed to radioactive rays may be detachably mounted on the screened-off portion of the continuous mixer, so that only one portion of the continuous mixer ever becomes unusable because of such rays and has to be replaced. Correspondingly little waste is produced by this continuous mixer itself.

The present invention will be further illustrated, by way of example, with reference to the accompanying drawings, in which, shown schematically: Figure 1 is a plan view of a device for removing radioactive substances by embedding them in a mortar mixture; Figure 2 is a view of the device of Figure 1; Figure 3 is a longitudinal section, on an enlarged scale, through the region of the continuous mixer for the mortar mixture, to which region the solid and liquid constituent parts for removal are supplied; and Figure 4 is a schematic plan view of the layout for the system.

As illustrated, a device generally referenced 1, serves to remove radioactive substances; however, the device may also be used similarly to remove toxic substances. In such a case, the substances to be removed should be embedded in a setting mortar or plaster substance, with which they are mixed beforehand. It is therefore advantageous if such a mortar mixture has to be prepared with water in order to set, so that radioactive, toxic or otherwise contaminated water, appropriate solutions or sludge may also be removed simultaneously.

For this purpose, the device 1 has a continuous mixer 2 having a supply region 3 for the mortar mixture, wherein a metering region 4 and, connected thereto, a mixing region 5 are provided behind the supply region 3. The boundary between the metering region 4 and the mixing region 5 is seen particularly clearly in Figure 3, where the end of a metering conduit 6 is shown with a metering screw 7 and an extended portion, connected thereto, is shown extending into the mixing portion 5. The metering region 4 in this case is double-walled, so that the outside surface of its mixer housing 8 is flush with the mixing region 5 despite the transitional shoulder between the metering conduit 6 and the mixing region 5.

This portion of the continuous mixer 2 may be inserted correspondingly easily through a screening wall 9 which will be described hereinafter, radioactive radiation being present behind this screening wall 9. Accordingly, at least the mixing region 5 is screened from the supply region 3. In such a case, the anti-radiation screen 9 is provided in the metering region 4 of the continuous mixer 2 on the outside surface thereof, while the supply line for the substances to be removed-viewed from the supply region 3 for the mortar mixtures disposed behind the screen 9. The non-radioactive substances, i.e. the mortar mixture, may easily therefore be introduced in front of the screen, while the radioactive substances are mixed therewith behind a screen in a manner commonly used hitherto.

The inlets for the substances to be removed are disposed in the mixing region 5, and hence in the wet region of the continuous mixer 2, so that, by means of the metering screw 7, the mortar mixture may be first metered accurately so as then to absorb the substances to be removed. In such a case, a connection 10, for the introduction of solid substances, is provided immediately behind the metering region 4, and the connection 11 for mixing-water, preferably radioactive or contaminated water for removal, or other liquid constituent parts is provided behind the connection 10 in the direction of conveyenace.In Figure 3, a connection 12 is also seen which is located even slightly further behind the direction of conveyance, through which connection 12 contaminated exchange resins or similar waste substances which are also produced, especially in nuclear power stations, can be supplied to the continuous mixer 2, these waste substances neither being called solid substances, nor being suitable for preparing the mortar mixture, but nevertheless have to be removed.

In such a case, a worm conveyor screw 13 is provided within a conveyor conduit 14 for supplying solid, comminuted substances, which conveyor conduit angularly, rectangularly in the embodiment, discharges into the continuous mixer housing transversely to the advance direction of the binding agent mixture. Because the material is introduced transversely, the desired mixing commences immediately between the still dry mortar or plaster mixture and the solid substances which are to be removed and which come from a comminuter/pulveriser or storage container 1 4a.

As already mentioned, the continuous mixer 2 extends behind the metering conduit 6; in the embodiment, another worm conveyor screw 1 5 is provided in a first portion of the mixing region 5, and the solid substances for removal can be supplied to the region of this worm conveyor screw, while a paddle mixer screw 1 6 is provided in the region of the water and sludge supply line 11 and permits a more thorough mixing between solid and liquid constituent parts; additionally the paddle mixer screw 1 6 also convey these mixed constituent parts gradually to the outlet 1 7 of the continuous mixer 2.

In Figure 2, it can be seen that the continuous mixer 2 is disposed so high above the ground that the device 1 has such high feet or supports 1 8 that a drum 1 9 or another container for accommodating the waste fits beneath the discharge aperture 17. The container 1 4a for solid waste and the container 1 2a for exchange resins are also disposed at a correspondingly high level.

Since the portion of the continuous mixer 2 which is exposed to radioactive rays, is especially the mixing region 5, and also a portion of the metering region 4, then advantageously the entire metering region 4 may be detachably mounted on the outer portion of the continuous mixer 2, i.e.

especially on the supply region 3, so that accordingly only this detachable portion has to be removed and replaced after a certain length of time when the radioactive contamination has damaged the continuous mixer 2.

By means of the device 1 according to the invention, it is possible to mix and set radioactive substances, liquids, mixtures and the like with an initially dry mortar mixture in a convenient and simple manner, whereby the use of the continous mixer permits such substances for removal to be intimately mixed and consequently for them to be absorbed to a correspondingly high degree in a limited space. In such a case, radioactive water may simultaneously also be used advantageously to prepare the mortar and may itself be removed thus in correspondingly large quantities. The appropriate container 11 a for water or sludge, having a supply line 11 b leading to the connection 11, can be seen in Figure 1.

The system shown in Figure 4 for operation with radioactive substances, such as, for example, a radiators, is accommodated in the interior chamber 132 of a simple glove box 101 and is accessible in known manner via the glove apertures 102. For high screening requirements, it is possible to surround the glove box 101 with lead bricks or tiles or to accommodate the system entirely in a hot cell. However, the illustrated embodiment is particularly favourable since it can easily be made mobile. On its underneath side, the glove box 101 has an aperture 122, to which waste drum 106 to be filled is connected by means of the so-called "double cover technique" in a manner which is not shown more fully.

The essential components of the system are not disposed in the glove box 101 in a special manner. The central element thereof is the continuous mixer 103 which comprises a cylindrical housing 104 with a mixer shaft 130 having a mixing and kneading screw running therein. The mixer shaft 1 30 is placed upon the shaft of the worm conveyor screw 109 of conveyor 131, via a plug coupling 129, for the delivery of the dry cement mixture and can easily be removed for cleaning purposes or for replacement. By means of the screw 109 of the conveyor 131, dry cement is supplied in the direction of conveyance shown by arrow 11 8 to the mixer 103 via feed aperture 107 from outside of the glove box 101. The housing 108 of the conveyor 1 31 for the cement or the dry mixture is thereby conducted through the wall of the glove box 101 into the interior chamber 132, whereby the portion of the housing 108 containing radioactive substances is located wholly within the box 101.

A pivotable guide or baffle plate 123 is mounted beneath outlet aperture 105 formed in the continuous mixer 103, and the emergent, completely mixed and metered waste arrives in the drum 106 through the aperture 122 via the plate 123.

The worm conveyor screw 109 of the conveyor 131 is driven by motor 133 and is fed from above from store 126 for the dry cement mixture. The motor 1 33 and the store 126 are located externally of the glove box 101. Consequently, the continuous mixer shaft 1 30 and the worm conveyor screw 109 form, with their housing 104 and 108, a coaxially combinable unit.

The supply lines for the further mixture components are now attached to the above housings or to the mixer housing 104. Viewed in the direction of conveyance shown by arrow 11 8, the supply line for dry shredder material appears first in the form of a screw conveyor 11 6, the housing 11 5 of which is connected with its outlet aperture 117 to the conveyor housing 108.

Consequently, for example, shredded, dry filter materials may first be added to the cement and then mixed by means of the screw 109 and the front portion of the mixer shaft 1 30.

The shredder material is delivered into the housing 11 5 from store 124 which is connected to a comminuting means (not shown more fully) and, together with this means, is located within the glove box 101. The motor 134 for the screw drive may be located externally of the box 101 and its speed can be regulated.

Viewed in the direction of conveyance shown by arrow 118, the mouth 114 of a supply line for the liquid components for the mixture is mounted on the continuous mixer housing 107 behind the delivery line for the shredder material. These liquid components comprise liquid radioactive waste and an additional quantity of fresh-water which has been metered and added. This additional metering is effected via the line 11 3 which is connected to the other supply line 110 for the radioactive concentrates in the region of its mouth 114. The supply line 110 leads to a receiver or storage container 111 for the liquid radioactive waste. This container 111 may be vacuum-filled and may be emptied preferably with a small excess pressure or by gravity. It may also be connected to a weighing means (not shown).The container 111 is filled by means of vacuum pressure line 128 which is blockabie at any desirable time or by means of concentrate supply line 127. A metering valve 112 is inserted into the line 110.

A further conveyor is also now connected to the continuous mixer housing 103, the outlet aperture 1 21 of which conveyor discharges into the interior chamber of its housing 104 and the screw 1 20 of which, with its housing 11 9, serves to meter wet or viscous radioactive ion exchange resins. Like the store 124, the store 125 for the resins is located within the glove box 101, but the drive motor 1 35 is located externally of the glove box 101 for maintenance purposes.

The system as described now operates as follows: Experiments have shown that it is possible in practice to mix ion exchange resins, shredded combustible waste and evaporation concentrates in any desirable ratio. A commercially conventional mixture is used to set the radioactive waste. This mixture essentially comprises cement, lime, sand and various chemical additives which are to cause the product to gel rapidly and set.

The dry mixture may be delivered either from bags into a hopper located externally of the glove box 101 or via a worm conveyor screw from a silo.

The dry mixture is conveyed from the delivery hopper into the glove box 101 by means of the worm conveyor screw 109. The speed of conveyance of the dry mixture is constant.

Evaporation concentrate is used as the liquid. The evaporation concentrate is also located in the metering vessel 111 which is disposed externally of the box 101 at any desirable location. This metering vessel 111 is filled via a vacuum pressure system. Filling is effected in such a manner that the metering vessel 111 is put under vacuum by means of the line 128 and thus, after a concentrate line 1 27 has been opened, liquid can flow into the concentrate metering vessel 111 from a concentrate container located at any desirable place. The filling level of this apparatus may be limited by a weighing means, so that the supply valve is automatically closed when a set filling level is reached.The vacuum in the container is then broken and replaced by a pressure pad, by means of which the liquid concentrate may be conveyed from the metering vessel 111 into the mixer 103. The metering is effected by the adjustable metering valve 112.

The quantity of liquid to be supplied is dependent on the addition of the further radioactive materials, e.g. the shredder material or the ion exchange resin. Shortly before the desired filling level is reached in the waste drum 106, the metering valve 112 on the metering container 111 is closed and the fresh-water valve 136 in the line 11 3 is opened. It is thereby possible to concrete a largely inactive seal onto the radioactive mixture in the drum 106.

The store 124 or the delivery means for shredded, combustible or packageable waste is located within the glove box 101 and is connected to the mixer 103 by a worm conveyor screw 11 6. The shredded material is fed into the box 101 in any desirable containers and then taken to the store. It would also be possible for the shredded material to be added via a pneumatic conveying means. Thus, the shredder material could be produced at a different location and supplied to the system. As already mentioned, the shredder material is now added in the dry region of the mixer 103, i.e. before the addition of liquid or, however, at the end of the worm conveyor screw 109 for the dry mixture.

The worm conveyor screw 11 6 for the shredder material is provided with a controllable motor 134 so that the quantity, and hence the mixture, can be adjusted in the waste drum 106.

Ion exchange resins of any desirable quality may be supplied to the mixer from the store 125, which is also located in the box 101, and via a worm conveyor screw 1 20 located beneath the store 125. The ion exchange resins are introduced, via a sluice, into the box 101 in any desirable vessels or introduced by another conveyor means from a silo located externally of the box. The inlet 1 21 of the worm conveyor screw 120 for ion exchange resins lies, by way of contrast to the shredder material, behind the liquid supply line 114 on the continuous mixer 103. The ion exchange resin is thereby introduced into an already wetted zone. The motor 135 of the worm conveyor screw 120 for ion exchange resins can also be reguiated.

As already mentioned, a continuous mixer 103 is located within the box 101 as an extension of the worm conveyor screw 109 for the dry mixture. The arrangement of the supply lines has already been described above. The housing 104 of the mixer is connected to the dry mixing area 131 via a wedge-shaped closure member. At the outlet 105, the mixer 103 has a pivotable baffle plate 123, by means of which the finished mixture can be embedded in the drum 106. By means of a lifting device (not shown), this drum 106 is urged beneath the table of the glove box 101. A double cover system may be used as the closure means for the drum. By pivoting aside the baffle plate 123, the entire aperture 122 formed in the drum 106 now becomes exposed, so that this drum may be sealed with a simple double cover which pivots away upwardly. After the liquid supply lines and the ion exchange screw have been disconnected, the mixing tube or the housing 104 and the mixing tool 130 may be removed forwardly with a small number of manipulations and be cleaned mechanically. In the case of systems for medium-active waste, this cleaning process may be effected by remote control with manipulators.

Claims (29)

Claims

1. A method of removing and cementing radioactive and/or toxic substances, whereby such substances are embedded in a setting or hardening binding agent mixture and are poured into containers or drums, in which a substantially dry binding agent mixture is introduced into a chamber or the like, which is screened from radiation, is there mixed with the substances to be removed and is allowed to harden.

2. A method as claimed in claim 1, in which the binding agent mixture is mixed at least with radioactive and/or contaminated water and is thereby prepared for hardening.

3. A method as claimed in claim 1 or 2, in which, after being prepared and prior to setting, the mixture is poured into a storage drum or the like.

4. A method as claimed in claim 1,2 or 3, in which, in addition to the water, the comminuted material (shredder material) is mixed with the binding agent mixture and is poured into a drum or the like.

5. A method as claimed in any one of claims 1 to 4, in which an initially dry mortar mixture serves as the binding agent mixture and is conveyed into a mixing apparatus in the radioactive chamber.

6. A method of removing and cementing radioactive and/or toxic substances, as claimed in any preceding claim, substantially as hereinbefore described and illustrated.

7. Apparatus for cementing radioactive or toxic waste in drums, wherein the toxic waste is embedded in a setting or hardening cement mixture and is poured into a drum, wherein the mixture constituent parts or components are added from various stores and the drum to be filled is detachably connected to a glove box, which accommodates at least parts of the apparatus, or the drum to be filled is detachably connected to a hot cell with the application of the double cover technique, in which a continuous mixer is located in the glove box or in the hot cell and is provided with a housing, the continuous mixer feeding the drum with the discharge of the housing, and a conveyor is provided and is connected to the feed aperture of the continuous mixer for the delivery of the dry cement mixture, the supply line for the liquid components of the mixture being connected to the conveyor in the region of the feed aperture.

8. A cementing apparatus as claimed in claim 7, in which the supply line for the liquid components is connected to a storage container for liquid, radioactive concentrates, and means exist for the metering of such concentrates.

9. A cementing apparatus as claimed in claim 8, in which a fresh-water metering line is connected to the supply line for the liquid, radioactive concentrates or in the region of the mouths of the supply line which discharge into the continuous mixer housing.

10. A cementing apparatus as claimed in claim 7, 8 or 9, in which a further worm conveyor screw housing, with its outlet aperture, is connected to the continuous mixer housing or to the worm conveyor screw housing for the dry cement mixture-viewed in the direction of conveyance-in front of the mouth of the supply lines for the liquid components and is capable of being fed with dry shredder material.

11. A cementing apparatus as claimed in claim 7, 8, 9 or 10, in which a further worm conveyor screw housing with its outlet aperture, is connected to the continuous mixer housing viewed in the direction of conveyance-behind the mouth of the supply lines for the liquid components and is capable of being fed with liquid or wet ion exchanger resins.

12. A cementing apparatus as claimed in any one of claims 7 to 11, in which a pivotable baffle plate extends beyond the feed aperture and is mounted beneath the outlet aperture of the continuous mixer housing.

13. A cementing apparatus as claimed in claim 11, in which the storage means or delivery means for the worm conveyor screws for the dry shredder material and for the liquid or wet ion exchange resins are located within the glove box or within the hot cell, and the store for the dry cement mixture is located externally of the glove box.

14. A cementing apparatus as claimed in claim 13, in which the two worm conveyor screw housings are also located entirely within the glove box or within the hot cell.

1 5. A cementing apparatus as claimed in claim 14, in which the storage container for the liquid, radioactive concentrates, together with its blockable concentrate supply line is connected to a further blockable line which is actuable with pressure and vacuum, and in which a metering valve is inserted into the line between the storage container and the continuous mixer housing.

16. A cementing apparatus as claimed in claim 15, in which the components, which are supplied by means of the worm conveyor screws, are each capable of being metered independently of one another by the appropriate regulation of the speed of conveyance.

1 7. An apparatus for cementing radioactive or toxic waste in drums, substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings.

1 8. A device for removing radioactive and/or toxic substances, in which a continuous mixer is provided with a supply region for a binding agent mixture, in which a metering region and, connected thereto, a mixing region are provided behind the supply region and in which at least the mixing region is screened from the supply region on the outside surface of the device.

19. A device as claimed in claim 16, in which a screen, especially an anti-radiation screen, is provided in the metering region of the continuous mixer on the outside surface thereof, and the supply line for the substances to be removed viewed from the supply region-is arranged behind the screen.

20. A device as claimed in claim 18 or 19, in which the inlet for the substances to be removed is disposed in the wet region of the continuous mixer.

21. A device as claimed in claim 18, 19 or 20, in which at least one connection is provided immediately behind the metering region for the introduction of the shredder material, and a connection for mixing-water is provided behind the connection in the direction of conveyance.

22. A device as claimed in claim 1 8, 19 or 20, in which a worm conveyor screw is provided within a conveyor conduit for supplying solid substances, which conveyor conduit angularly, discharges into the continuous mixer housing transversely to the advance direction of the binding agent mixture.

23. A device as claimed in any one of claims 1 8 to 22, in which the continuous mixer extends behind the metering conduit and has a worm conveyor screw in a first portion of the mixing chamber, the solid substances to be removed being capable of being supplied to the region of the worm conveyor screw, and in which a paddle mixer screw is provided in the region of the water or sludge supply line.

24. A device as claimed in any one of claims 18 to 23, in which the continuous mixer is disposed so high above the ground that a drum for radioactive and/or toxic waste fits beneath its discharge aperture.

25. A device as claimed in any one of claims 1 8 to 24, in which the portion ofthe continuous mixer which is exposed to radioactive rays is mounted on the screened portion of the continuous mixer.

26. A device as claimed in any one of claims 1 8 to 25, in which the external cross-sections of the metering region and the mixing region are identical.

27. A device as claimed in any one of claims 1 8 to 26, in which the metering conduit has a narrower cross-section than the mixing region and is surrounded by a second housing which is flush with the mixing region.

28. A device as claimed in any one of claims 18 to 27, in which a further supply line discharges into the region of the water supply line or therebehind.

29. A device for removing radioactive and/or toxic substances, substantially as hereinbefore described with reference to and as illustrated in Figures 1, 2 and 3 of the accompanying drawings.