RU2704311C2 - Tight sealed container for transportation of package with radioactive wastes (rw) and method of packaging formation and handling in this container - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: group of inventions relates to nuclear engineering. Reusable sealed container for transportation of radioactive wastes (RW) package contains housing, cover installed with formation of clearance for installation and clamping of radiation-resistant rubber seal, and opposite located at equal distance wedge locks, cylindrical supports of which are located on housing, and angular on cover and are connected by wedges of cylindrical shape with transition to angular surface. Side surfaces of cover and recesses of upper part of housing have z-like planes at angle of 15° to vertical plane, providing installation of cover relative to housing with labyrinth gap 2÷3 mm along the entire perimeter. Bottom of lid has ledge with height of not more than 8 mm. Side walls are made at angle of 45° towards inner cavity of housing. Inner and outer surface of the body and the cover are coated with a coating which is resistant to deactivating solutions. There is also a method of forming and handling radioactive wastes package in a container.

EFFECT: group of inventions makes it possible to increase manufacturability and reduce labour intensity during loading-unloading operations of radioactive waste package.

2 cl, 7 dwg

Description

The invention relates to nuclear engineering in the field of solid radioactive waste management at the stages of collection, formation, temporary and long-term storage, transportation as part of a transport packaging and disposal in near-surface or deep underground burial facilities.

A reinforced concrete container is known in which the side walls of the lid and the side walls of the recess of the body have wedge-shaped protrusions offset by one relative to each other, and a gap is made between the protrusions to fill the expanding alumina cement with a sealing adhesive material (RF patent No. 2056653).

This container cannot be used as a revolving one, because after loading the RW container and installing the lid, the lateral gap between the body and the lid is filled with a special sealing binder (a solution of expanding alumina cement), which must be removed when unloading the RW from the container before removing the lid. Such an operation is very laborious, and in radiation fields it is radiation hazardous. During this operation, the sealing surfaces of both the case and the cover will be violated, therefore, the container in question cannot be used as a revolving one.

In addition, the absence of mechanical clamping locking devices of the lid with the housing also leads to a decrease in the tightness of the lid-housing joint and its strength, both under normal operating conditions and in emergency situations.

Also known is a concrete container for long-term storage and transportation of radioactive waste (RF patent No. 2195724), comprising a housing, a cover made under a recess in the upper part of the housing and secured to the housing by separate wedge locks, and there is a gap extending upward between the side walls of the housing and the cover for filling with gypsum-alumina expanding cement, which is a sealing material.

After loading the RW into this container, installing the lid and locking the wedge locks, the gap between the lid and the body is expanded with gypsum-alumina expanding cement, which must be removed when unloading the RW from the container before removing the lid. Such an operation is very laborious and radiation hazardous. At the same time, the sealing surfaces of the lid and the housing will be violated, and, therefore, the container itself becomes non-serviceable and cannot be negotiable.

The disadvantage of this container, in addition to the above, is that in the deep space between the upper edge of the housing and the top of the lid, formed to vertically stack containers after deactivation of its outer surfaces, radioactive water accumulates due to the lack of drainage devices from these spaces.

Closest to the claimed technical solution is a steel-reinforced concrete container sealed for storage, transportation and disposal of radioactive waste and a method for its manufacture (RF patent No. 2315379), comprising a housing, a lid installed in a recess of the upper part of the housing with the formation of a gap between their side walls for installation sealing material, as well as wedge locks opposite to the perimeter of the housing, cylindrical supports of which are located on the housing, and wedge locks on the lid and are connected by wedges. The lock supports are mounted on flat steel bases, anchored in the reinforced concrete structures of the housing and the cover, and the said gap between the housing and the cover is made expanding downward and has a gap in the upper part of 20–30 mm.

After loading the RW into this container, installing the lid and locking the wedge locks, the gap between the lid and the body is filled with sealing material, which must be removed when the RW is unloaded from the container before removing the lid. This operation is time-consuming and radiation hazardous, at the same time, the sealing surfaces of the lid and housing will be violated, the container itself becomes non-repairable and, therefore, cannot be negotiable.

The present invention is the creation of a negotiable, sealed for handling solid RW container at the stages of collection, the formation of packaging with RW in this container, transportation as part of a transport packaging set, unloading from the container of packaging with RW in long-term storage or disposal facilities, carrying out, if necessary decontamination to prepare the container at the point of return.

The technical result obtained by the implementation of the invention consists in its turnover, as well as improving manufacturability and reducing the complexity during the loading and unloading of packaging with radioactive waste.

In the proposed technical solution, the sealed revolving container for radioactive waste management contains a housing, a lid installed in a recess in the upper part of the housing to form a gap for laying and clamping a radiation-resistant rubber seal around the perimeter of the lid, and wedge locks, which are oppositely spaced at equal distances, whose cylindrical supports located on the body, and angular on the lid and connected by wedges of a cylindrical shape with the transition to a corner surface. The lateral surfaces of the lid and the lateral surfaces of the recesses of the upper part of the housing have z-shaped planes at an angle of 15 ° to the vertical plane, providing installation of the cover relative to the housing with a labyrinth gap of 2-3 mm around the entire perimeter and uniform clamping of the rubber seal, while the bottom of the cover has the shape of the protrusion, the height of which is not more than 8 mm, and its side walls are made at an angle of 45 ° towards the inner cavity of the housing.

On the inner and outer surfaces of the housing and the cover is coated resistant to decontamination solutions.

The container also includes a sealed liner with a substrate, made in accordance with the shape of the internal cavity of the container body, and a sling device with cargo brackets that can be temporarily stored, for example, in the internal cavity of the container body.

The walls of the internal cavities of the container body are made with a slope that ensures manufacturability when concreting the body and removing the formwork, as well as the convenience of unloading the packaging formed in the container with radioactive waste.

Due to the fact that the lateral surfaces of the lid and the lateral surfaces of the recesses of the upper part of the housing have z-shaped angular planes made of steel and providing the installation of the lid relative to the housing with a labyrinth gap of 2-3 mm around the entire perimeter, are achieved:

- uniform clamping of the rubber seal;

- uniform locking of wedge locks;

- obtaining the possibility of interchangeability of cases and covers and the accuracy of their collection among themselves on the wedges of wedge locks;

- reducing the complexity of the installation and fixing operations of the cover on the housing;

- reduction of radiation to personnel due to a labyrinth gap of 2-3 mm around the perimeter between the cover and the body;

- no need to fill the gap between the housing and the cover with a special expanding cement mortar, since this function is performed by a rubber seal.

The protrusion at the bottom of the lid with a height of not more than 8 mm with side walls at an angle of 45 ° to the side of the inner cavity of the casing allows sealing the polymeric mineral Cambrian clay covered in the free volume and thereby creating a protective barrier against migration of radionuclides and additional tightness between the casing and the lid container.

Coating all internal and external surfaces of the container, resistant to decontamination solutions, will allow multiple decontamination, which is one of the main requirements of a revolving container.

A sling device with cargo brackets freely placed in the container body, into which a sealed liner with a substrate is enclosed, made in accordance with the shape and dimensions of the container’s inner cavity, allows to put radioactive waste in a sealed polyethylene liner, pour concrete and cure it without adhesion of the poured concrete to the side the surfaces of the internal cavity of the container, that is, create a packaging with radioactive waste for disposal, consisting of a sling device with cargo brackets, a sealed liner with a monolith RW and its substrate, transport the container with the packaging from the RW to the RW long-term storage or disposal facilities (MPH or PZ), where to unload the RW packaging from the container and place it in a regular place for long-term storage or disposal.

The dimensions and the z-shaped configuration of the labyrinth gap when installing the lid in the container body, the size and shape of the protrusion on the bottom of the lid, the clamp of the rubber seal, the amount of underfilling of the cement mortar in the sealed RW insert, the height of the backfill in the free volume of the Cambrian clay polymer clay were experimentally verified using mock up container.

Due to these distinguishing features, the functionality of the containers has been expanded, since the same container can be used not only at all stages of radioactive waste management (collection, sorting, repacking, temporary storage, transportation and disposal of radioactive waste), but it can also be easily unloaded packaging with radioactive waste for long-term storage or disposal, while the container itself becomes turnaround.

The introduction of recycled containers for radioactive waste management in the field of nuclear energy will allow several times to reduce the number of existing containers for radioactive waste management (currently 10,000 ÷ 15,000 pcs.), Which will have a great economic effect, since the cost of manufacturing one container is 120,000 ÷ 150,000 rub.

As a prototype of the claimed method for the formation and handling of packaging with radioactive waste in a revolving container, the method described in the description of the patent of the Russian Federation No. 2315380 was selected. The method of cementing radioactive waste according to the prototype is carried out in a container where the radioactive waste is stored, and after the cement compound is solidified with radioactive waste, the free volume of the container is filled with a non-radioactive protective coating - polymineral Cambrian clay to the top of the inner cavity of the container, which is then sealed with a lid for sealing.

The disadvantage of this method of forming packaging with radioactive waste in a container for transportation to long-term storage facilities is that as a result of its implementation, adhesion of the inner surface of the container body and cement binder with radioactive waste occurs, and, as a result, a reinforced concrete monolith that cannot be used as a returnable container is obtained , but it can be installed for long-term storage or burial in storage.

In the proposed method for the formation and handling of RW packaging in a container in the inner cavity of the container body, operations are carried out in the indicated sequence:

- they put inside the container body a sealed liner with a substrate and a sling device;

- in a sealed liner with radioactive waste, pour cement mortar with underfilling of 40 ÷ 50 mm to the upper edge of the inner cavity of the container body;

- for three days spend technological exposure to cure the cement mortar;

- put a rubber seal in the case;

- fill the remaining internal free volume with Cambrian clay polymineral clay to a level of 4 ÷ 5 mm from the reference plane of the body-cover;

- install a cover on the case and lock it on the case with wedge locks;

- conduct radiation monitoring of the outer surfaces of the container;

- the container is sealed, marked and transported to the RW disposal site, where the package is unloaded from the RW.

The listed operations, their sequence of formation and handling of packaging with radioactive waste allow:

- create an airtight universal packaging with monolithic type radioactive waste within the internal overall dimensions and configuration of the cavity of the container body, airtight liner and substrate;

- create a packaging with radioactive waste, equipped with an individual sling device with cargo brackets, which ensures unloading of the packaging with radioactive waste from the container and install it at the place of regular storage or disposal without any additional preparation and without the use of a special traverse;

- create a package with radioactive waste, which, after hardening the cement mortar with radioactive waste with a sealed liner on the substrate, could be freely discharged from the cavity of the container body due to the lack of adhesion between the surface of the cavity of the container body and the formed packaging of radioactive waste. There is no adhesion process between the cement surface of the container and the plastic film of the sealed liner;

- as a result of underfilling of the cement mortar in the sealed liner with radioactive waste by 40 ÷ 50 mm to the upper edge of the inner cavity of the container body, create an internal free volume between the lid and the upper surface of the packaging with radioactive waste, which is covered with Cambrian clay and when installing the lid on the body using the protrusion at the bottom of the lid, a seal is made between the lid of the container and the body, while opening the wedge locks, the lid can be freely removed from the body, since the polymineral Cambrian clay is teach pictures;

- fill the internal free volume with polymineral Cambrian clay to a level of 5 ÷ 6 mm from the supporting surface of the lid body, which will allow using the protrusion on the bottom of the lid when installing it to seal the volume of polymineral Cambrian clay, and thereby create an additional, reliable immobilization barrier on ways of possible migration of radionuclides from the packaging with radioactive waste to the gap between the cover and the body.

In the proposed method, the clay coating in the form of polymineral clay backfill cannot be broken during transportation (it does not crack unlike cement).

Even if the lid is torn off the container during an accident and the (non-radioactive) clay spills out, the same clay can be re-filled and the protective coating restored. In case of leakage and moisture getting into the container, the coating becomes tight and plastic, ensuring the damage is tightened in the cement compound (packaging with radioactive waste) and the container.

The proposed sequence of operations of the method allows you to create an immobilization barrier on the paths of possible migration of radionuclides from the packaging with radioactive waste to the gap between the lid and the container body, to form an easily unloadable packaging with radioactive waste in the container, while the container itself becomes turnaround.

And so, the proposed group of inventions solves the problems of creating a revolving steel-reinforced concrete sealed container, increasing the reliability of sealing and the strength of the connection of its body and lid, expanding the functionality of the container, as well as the formation of packaging with radioactive waste in the container itself, ensuring its long-term storage or disposal in storage PDH and PZ.

The essence of the group of inventions is illustrated by the following graphic images:

FIG. 1. General view of the container (top).

FIG. 2. The vertical section of the container AA.

FIG. 3. Node B. Wedge lock assembly with rubber seal.

FIG. 4. Section BB. Seal between cover and housing.

FIG. 5. The scheme for the formation of packaging with radioactive waste in the container.

FIG. 6. The scheme for the formation of packaging with radioactive waste in the container and unloading the packaging from the container.

FIG. 7. Sketch of the formed packaging with radioactive waste.

The inventive circulating container is intended for the management of radioactive waste and the formation in it of packaging with radioactive waste.

The container consists of a sealed case 1 and a sealed cover 2 installed in its recess, pressed against each other on a supporting plane 3 by wedge locks 4. Each wedge lock consists of a cylindrical support 5 of the case and a wedge support 6 of the cover, which are interconnected by a wedge 7 (see Fig. 3). In this case, cylindrical and wedge supports 5 and 6, coaxially arranged pairs of wedge locks, are fixed by welding on the corresponding steel flat bases and fittings in the form of nets and frames, the casing and the cover, respectively, and concreted with heavy concrete in the corresponding reinforced concrete structures of the casing and the cover.

Between the side wall 8 in the recess of the housing and the side wall 9 of the lid there is a Z-shaped gap of 2 ÷ 3 mm around the entire perimeter. A Z-shaped gap 10 is formed between the angular and vertical planes of the side walls of the lid and the body when the lid 2 is installed on the container body 1 (see Fig. 4).

The planes 11 of the lid and the housing relative to the vertical planes 12 of the lid and the housing are located at an angle of 15 °, while the angular planes are deployed in opposite directions from the vertical plane. The specified angles provide the necessary alignment of the cover relative to the housing with a labyrinth gap of 2 ÷ 3 mm, and also provide the necessary compression of the rubber seal 27 when sealing the connector between the cover and the housing (see Fig. 4).

Mounting and dismounting the cover 2 on the housing 1 is carried out using lifting brackets 13 mounted on the cover (see Fig. 1 and 2).

For the convenience of transportation, lifting and compact multi-tier stacking of the container on the narrow lateral outer faces of the body, recesses are made - niches 14, which include standard gripping devices for lifting equipment, and for servicing with forklift trucks, special openings 15 are made in the lower part of the body (see Fig. 2 )

To seal the free volume filled with polymineral Cambrian clay, when the lid is installed in the body, the bottom of the lid 2 has the shape of a protrusion 16, the height of which is not more than 8 mm below the supporting plane of the lid towards the inner cavity of the container body. The side walls of the protrusion 16 are inclined along the entire perimeter to the center of the cover at an angle of 45 ° (see Fig. 4).

To form a package with radioactive waste, a sling device 17 with load brackets 18 is freely laid in the internal cavity of the housing 1, into which a sealed liner 19 with a substrate 20 is inserted, made in accordance with the shape of the internal cavity of the container body 1 (see Fig. 5-a).

The sling device 17 can be designed and manufactured in accordance with the sketch of FIG. 7. The sling device 17 can be made from commercially available Cheboksary JSC “Lenta” textile tape slings, for example, from polyester.

Advantages of tape soft slings:

- low dead weight, which makes it easy to move the load gripping device (in contrast to one made of metal);

- resistance to increased air humidity, radiation, UV radiation and chemically active environments (alkalis, acids, petroleum products);

- softness and elasticity of the material, giving convenience in manufacture and use;

- compactness during storage;

- minimal risk to personnel;

- high strength characteristics, wide temperature limits;

- reasonable price in comparison with chain or cable counterparts.

As cargo brackets 18 can be used staples (mass-produced) LLC Stropkomplekt.

The sealed liner 19 with the substrate 20 are made in accordance with the shape of the internal cavity of the housing 1.

Sealed liner 19 may be made of reinforced plastic film. Such a material consists of two plastic films, between which there are reinforcing threads of synthetic or natural fibers or a rare glass cloth. To protect the bottom of the sealed liner 19 from damage during the installation of radioactive waste, a substrate 20 is laid on the bottom of the sealed liner, made, for example, of a polyethylene sheet 4-6 mm thick.

Advantages of using plastic film and sheets:

- it is not wetted by water;

- resistant to the action of aqueous solutions of salts, acids, alkalis;

- resistant to shock loads;

- stable during operation at temperatures from -70 ° C to + 100 ° C;

- have increased radiation resistance;

- lack of adhesion between the contacting surfaces of products made of polyethylene and cement mortar.

On all internal and external surfaces of the housing 1 and cover 2, a coating resistant to decontamination solutions is applied in accordance with OST 95.10562-2001.

Loading into the container of RW, the formation and handling of packaging with RW in this container is carried out in the following sequence and is shown in FIG. 5 (5-a, 5-b, 5-c) and FIG. 6 (6-g, 6-d).

Step 1. FIG. 5 (5-a). In the container with the lid 2 removed, the sling device 17 with cargo brackets 18 is freely placed in the body 1. A tight liner 19 is placed inside the sling device 17, on the inner bottom surface 22 of which the substrate 20 is placed. RAO 21 is loaded onto the substrate 20.

Step 2. FIG. 5 (5-b). After loading a certain amount of RAO 21 into the inner cavity of the sealed liner 19, cement mortar 26 is laid with 40 to 50 mm underfill to the upper edge of the inner cavity of the housing 1. Technological exposure is carried out for 3 days to cure the cement mortar.

Step 3. FIG. 5 (5-c). After curing the cement mortar with radioactive waste, the sealed liner 19 is sealed as follows and in the indicated sequence:

- twist the neck 23 of the sealed liner 19;

- the lower part of the neck 23 is tied with a cord or adhesive tape (not shown in the diagram);

- the lower and upper parts of the neck 23 are sealed and fixed with adhesive tape on the outer surface of the sealed liner 19 (not shown in the diagram);

- install the rubber seal 27 (Fig. 3).

Cargo brackets 18 are deployed into the internal cavity of the housing 1 and the remaining free volume is filled with Cambrian polymineral clay 24 to a level of 4–5 mm from the supporting plane of the housing-lid. FIG. 4 (B-B section) and FIG. 5 (5-c);

Step 4. FIG. 6 (6-g). A lid 2 is installed on the housing 1, which is pressed by the bottom protrusion 16 under the action of the gravity of the lid 2 into the Cambrian polymineral clay 24, which is poured into the free volume between the lid 2 and the upper level 25 of the packaging with radioactive waste. Thus, a tight seal and an immobilization barrier are created between the cover 2 and the housing 1.

Close and seal all the wedge locks 4 (Fig. 3). An external radiation control of the container is carried out and, if necessary, decontamination is carried out. The container is fully prepared for transportation to the long-term storage or disposal of radioactive waste. For slinging the container, recesses are used - niches 14, and for slinging the lid - rigging brackets - 13.

Step 5. FIG. 6 (6-d). After delivery of the container with the packaging with radioactive waste to designated long-term storage or disposal sites, the packaging of radioactive waste from the container is unloaded, performing the following operations in the indicated sequence:

- wedge all the wedge locks 4 Fig. 3; FIG. 6 (6-g);

- remove from the housing 1 the cover 2 and the rubber seal 27;

- remove the polymineral Cambrian clay 24;

- the load brackets 18 are turned vertically and with the help of rigging slings 28 and the hoisting device 29 of FIG. 6 (6-d) unload the packaging with RAO FIG. 7 from the container body 1, and then install it at a regular place in the storage;

- perform radiation monitoring of the external and internal surfaces of the housing 1 and cover 2 and, if necessary, carry out decontamination;

- a rubber seal 27 is placed in the housing 1, a cover 2 is installed, all the wedge locks 4 are closed 4. 3 and fill. The container is ready for return to the RW collection and reprocessing facility.

Thus, the design features of the claimed container and the method of forming and handling the packaging with radioactive waste in this container together provide the properties of a returnable container and packaging with radioactive waste prepared for long-term storage and disposal in accordance with the requirements of radiation safety standards and the Federal State Unitary Enterprise National Operator.

Claims (2)

1. A sealed revolving container for transporting a package of radioactive waste (RW), comprising a housing, a lid installed in the recess of the upper part of the housing to form a gap for laying and clamping a radiation-resistant rubber seal around the perimeter of the lid, and wedge locks oppositely spaced at equal distances the cylindrical supports of which are located on the housing, and the angular ones on the lid and are connected by wedges of a cylindrical shape with a transition to an angular surface, characterized in that the lateral surfaces and covers and lateral surfaces of the recesses of the upper part of the housing have z-shaped planes at an angle of 15 ° to the vertical plane, providing installation of the cover relative to the housing with a labyrinth gap of 2 ÷ 3 mm around the entire perimeter, while the bottom of the cover has a protrusion whose height is not more than 8 mm, and its side walls are made at an angle of 45 ° in the direction of the internal cavity of the housing, the inner and outer surfaces of the housing and lid are coated with a coating that is resistant to decontamination solutions, and is also equipped with a sealed liner with a substrate, anufacture in accordance with the shape of the internal cavity of the container body, and a sling device for insert. 2. A method of forming and handling a package of radioactive waste in a container according to claim 1, wherein the radioactive waste is placed inside the container and cement mortar is poured on top, and after hardening, the remaining free volume of Cambrian clay polymineral clay is poured, characterized in that it is previously laid in the internal cavity of the container body a sealed liner with a substrate and a sling device, and the cement mortar is poured with underfilling of 40 ÷ 50 mm to the upper edge of the container body; for the curing of the cement mortar, technological hold for three days, after which a rubber seal is placed in the casing, and filling with polymineral Cambrian clay is carried out to a level of 4 ÷ 5 mm from the supporting plane of the casing-lid, then the lid is mounted on the casing and locked with wedge locks, radiation monitoring of the container’s outer surfaces is carried out , they seal it and mark it, after which the container is transported to the RW disposal site, where the packaging with RW is unloaded in an airtight insert using its sling device.

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