EP3203482B1 - Final storage container and method for drying contaminated objects in a final storage container - Google Patents

Description

The invention relates to a method for drying in particular contaminated objects in a repository container according to the preamble of claim 1 and a repository container according to the preamble of claim 7.

Repository containers are used in particular for receiving objects or residues that require long-term disposal without coming into contact with the environment. For example, take such repository containers lumpy or free-flowing objects that are radioactively, chemically and / or biologically contaminated. The residues or objects are permanently hermetically sealed from the repository container by the environment.

Frequently repository containers are loaded with objects or residues that are moist or have residual moisture. Such objects or residues must be treated so that the moisture does not remain in the disposal container, which would lead in particular in connection with radioactive, chemical or biological contamination to rapid rusting and thus destroying the final storage container.

It is from the US 4,983,282 A known to dehydrate radioactive waste in a repository container by a vacuum pump. Such drainage is time consuming.

In the EP 0 355 514 A2 It is intended to condition radioactive evaporation liquors from nuclear facilities by heating the repository container to a maximum occurring in the repository temperature and extraction of water vapor until a solid body with a smooth surface in the repository container. There the heating of the evaporator liquors takes place only up to maximum temperature occurring in the repository, the known conditioning is not very effective.

From the US 3,404,722 A a device for concentrating liquid radioactive waste is known. This provides for putting on a disposal container on a lid with a steam-heated coil and to provide the container from the outside with detachable steam-heated shell parts. Steam heating requires a steam source. In addition, the steam-heatable coil and the outer steam-heated shell parts in the manufacture and handling are very expensive. Finally, the shell parts and the steam-heated spiral carrying lid must be removed after completion of the dewatering process.

The invention is based on the object to provide a method and a repository container, whereby a simple and effective drying of the particular contaminated objects is possible. The repository container should also be easy to produce.

A method for drying at least one contaminated article in a repository container comprises the measures of claim 1. By drying the at least one article in the repository container by heating it internally, it is possible to dry the contaminated article or objects if they are already in the repository. Characterized in that the at least one contaminated object is dried by a heater by means of a plurality of selectively operated heating elements inside the repository container, a heating of the interior of the repository container is carried out by the contaminated objects to be dried, whereby the air inside the repository container can absorb moisture , The multiple heating elements are selectively operated. It can be dried in several steps so that at least one located in the interior of the repository container contaminated object. Above all, the selective operation of the heating elements can also be used to bring about a specifically directed drying, for example from bottom to top. Also, it can be dried more intensively, where most of the moisture or moisture nests are. The moist air produced during drying is sucked out of the interior of the repository container. It thus comes to a flow of air inside the repository container, which causes a removal of moisture forming during drying.

By preferably continuous removal of the moist air during the drying process, the moisture is removed from the repository container. Especially the discharged moist air is replaced by dry outside air or dried air, so that the supplied air can absorb moisture by heating inside the repository container, which is transported by the suction of the heated, humid air from the repository container.

A preferred development of the invention provides for the removal of the resulting inside the repository container moist air. This will effectively avoid a permanent inclusion of moisture inside the repository container.

Preferably, the suction takes place by means of negative pressure, wherein optionally dry air or drier air is supplied to the interior of the repository container.

In particular, it is provided to dry the article (s) in the repository container by vacuum drying. As a result, a particularly effective drying takes place, especially if at the same time there is a discharge of the forming inside the repository container moisture.

The drying preferably takes place with a vacuum pump, which reduces the pressure in the interior of the repository container to less than 1 bar, preferably from 20 mbar to 50 mbar. This results in effective vacuum drying.

It is further preferred to determine the degree of drying or the drying criterion during the drying or in the final phases of the drying. This is done by measuring the time course of the pressure increase in the repository container with the vacuum pump switched off and completely airtight closure of the repository container. If, within a certain period of time, which can be up to one hour, the pressure rise below a certain value, which is preferably below 10 mbar, moves, the objects are sufficiently dried in the disposal container. Furthermore, it is preferably provided to bring the container internal pressure to a certain value for measuring the drying criterion. This value is preferably below 20 mbar.

A disposal container for solving the above-mentioned problem has the features of claim 4. In this repository container heating elements are assigned to the inner sides of at least some walls and / or the floor. It is also conceivable to provide in the interior of the repository container only those heating element, which are assigned to either a wall or only the ground. By the heating elements, the contaminated objects in the interior of the waste container by heating be dried. The respective heating element is designed as a Elektroheizpaneele.

Preferably, several Elektroheizpaneele are provided, and that may be assigned to the inside of at least one wall or the floor or they are distributed to different walls and / or the floor. The number and arrangement of Elektroheizpaneele can vary as desired; it is preferably linked to the largest heating power and can also be based on the nature of the at least one object to be dried or cooled in the interior of the repository container.

A preferred embodiment of the invention provides for assigning the Elektroheizpaneelen at least one protective element. The protective element, which is preferably a protective plate or protective panels, is associated with the interior facing surface of the respective Elektroheizpaneele. In this case, one or more protective elements preferably cover the entire area of each electric heating panel. The protective elements or protective plates can be arranged directly in front of the Elektroheizpaneelen and thereby either be in contact with the same or be arranged at a small distance in front of it. The protective elements serve for the mechanical protection of the electric heating panels. Thus, the protective elements prevent damage to the sensitive Elektroheizpaneele by the or each disposed in the interior of the repository container contaminated object. The full-surface protection of the inner sides of the Elektroheizpaneele is especially advantageous if stored in the interior of the repository container pourable or free-flowing objects or residues.

Fig. 1

eine perspektivische Ansicht eines Endlagerbehälters mit zwei auf diesem noch nicht aufgesetzten Deckeln,

Fig. 2

eine perspektivische Ansicht nur des noch offenen Endlagerbehälters,

Fig. 3

ein Endlagerbehälter in einer Ansicht der Fig. 2 im teilweisen Schnitt,

Fig. 4

einen mittigen Querschnitt durch den Endlagerbehälter der Fig. 1 bis 3, und

Fig. 5

eine teilweise geschnittene Draufsicht auf den noch unverschlossenen Endlagerbehälter der Fig. 1 bis 3.

Preferred embodiments of the invention are described below with reference to the drawing. In this show:

Fig. 1

a perspective view of a repository container with two on this not yet patch lids,

Fig. 2

a perspective view of only the still open repository container,

Fig. 3

a repository bin in a view of Fig. 2 in partial section,

Fig. 4

a central cross section through the disposal container of Fig. 1 to 3 , and

Fig. 5

a partially sectioned plan view of the still unclosed disposal container of Fig. 1 to 3 ,

The repository container 10 shown in the figures serves to receive at least one contaminated object. Preferably find in the interior 11 of the repository container 10 more contaminated objects recording. The items may be lumpy or pourable items. The repository container 10 is mainly used for long-term safe storage of contaminated objects, so-called residues. The articles or residues may be radioactively, chemically and / or biologically contaminated.

The repository container 10 shown is cuboid. However, the invention is also suitable for repository containers with any other shape, such as cylindrical repository containers.

The cuboid repository container 10 shown here has a flat bottom 12 with a rectangular base, two parallel side walls 13, two transverse thereto, parallel end walls 14 and a ceiling 15. The ceiling 15 is parallel to the floor 12 and has the same footprint. The side walls 13 and the end walls 14 are perpendicular to the horizontal floor 12 and the ceiling 15th

The disposal container 10 of the embodiment shown has at all eight corners on corner fittings 16. This is preferably this corner fittings 16, as found in ISO freight containers use.

The ceiling 15 of the repository container 10 is provided with a large-area opening 17. The opening 17 extends over a majority of the surface of the ceiling 15. The opening 17 is rectangular in shape, in such a way that their edges with equal, small distances to the outer surfaces of the end walls 14 and the side walls 13 extend. The corners of the opening 17 are chamfered, so that they leave the corner fittings 16. Through the opening 17 contaminated objects, in particular residues, can be filled into the interior 11 of the repository container. The opening 17 is closable in the repository container 10 shown here by two covers, namely a lower, inner primary cover 18 and a secondary cover 19 covering this from the outside. The secondary cover 19 is slightly larger than the primary cover 18, so that it extends around over the edge of the Primary cover 18 protrudes. Both the primary lid 18 and the secondary cover 19 are bolted separately to the ceiling 15, by a plurality of indicated in the figures screws 20. The lid 18 and 19 may be permanently connected to the ceiling 15 but in other ways, for example by riveting, Welding and / or gluing.

The opening 17 is surrounded by a stepped edge. A deeper first stage is used for flush receiving the primary cover 18, so that can be placed on the overlying, larger second stage of the secondary lid 19. The second stage is so deep that the secondary lid 19 is flush with the top of the ceiling 15 ( Fig. 4 ). A circumferential support surface for the lower primary cover 18 on the lower level of the edge of the opening 17 is provided in the embodiment shown with two adjacent, circumferential seals 21. As a result, the primary cover 18 is sealed in the screwed onto the opening 17 state, thereby ensuring an airtight seal of the interior 11 of the repository container 10.

The side walls 13, the end walls 14, the bottom 12 and the ceiling 15 are formed relatively thick. The thickness of the walls 13, 14, the floor 12 and the ceiling 15 are sized to prevent leakage of contaminated articles from the interior 11. Preferably, the walls 13, 14, the floor 12 and the ceiling 15 are sandwiched, namely, consist of an outer steel wall, a middle concrete layer, which is preferably reinforced, and an inner steel wall. However, it is also conceivable to form the walls 13, 14, the floor 12 and the ceiling 15 completely from solid steel or from steel and other materials which prevent the permeability of radioactive radiation or severely restricting materials, for example lead.

The interior 11 of the repository container 10 shown here can be heated. For this purpose, the inner sides of the side walls 13, the end walls 14 and the bottom 12 heating elements are assigned. Optionally, the ceiling 15 may be provided with heating elements. The heating elements are formed in the embodiment shown as electrically operated heating panels 22. The heating panels 22 are associated with the inner sides of the side walls 13, the end walls 14 and the bottom 12 and preferably fastened here. A plurality of adjacent heating panels 22 preferably extend over all or a major portion of the inner surface of the floor 12. The side walls 13 and the end walls 14 are only partially, viz., A lower part extending over the Half to two thirds of the height of the side walls 13 and the end walls 14 extends, provided with adjacent heating panels 22 on its inside.

The heating panels 22 are protected for mechanical protection against damage caused by the accommodated in the interior 11 of the repository container 10 items. Serve for this purpose from the inside of the repository container 10 forth in front of the Heizpaneelen 22 arranged cover plates, which are designed so that they protect the underlying 22 Heizpaneele mechanically against damage from the objects in the interior 11. The heating panels 22 protecting cover plates 23 are arranged without gaps in front of the Heizpaneelen 22 of the side walls 13 and the end walls 14 and the Heizpaneelen 22 on the floor 12. In the region of the walls 13 and 14, the cover plates 23 extend over the heating panels 22 across the entire height of the side walls 13 and the end walls 14. At least above the heating panels 22, the cover plates 23 are fixed to the inner surfaces of the side walls 13 and the end walls 14. As a result, the sections of the cover plates 23 extending above the heating panels 22 abut against the inner sides of the side walls 13 and the end walls 14, respectively (FIG. Fig. 4 ).

The cover plates 23 are formed of a good thermal conductivity properties having material, such as steel. To improve stability, the cover plates 23 may have profiled cross sections. It is also conceivable that between adjacent Heizpaneelen 22 spaces and the cover plates 23 are profiled so that they fill these spaces and supported in the interstices on the inner sides of the side walls 13 and the end walls 14 and optionally the bottom 12 and attached thereto are.

Power supply lines of the heating panels 22, in particular power cables in electrically operated heating panels 22 are led out of the heating panels 22 in the interior 11 of the repository 10 by a closable by a lid 24 opening from the repository 10 to a power supply and control. Preferably, there are under the cover 24 sockets for leading inside the repository 10 to the heating panels 22 power lines. At these sockets 24 plugs of the external supply lines are connected with the cover removed.

The invention provides a control that allows the heating panels 22 to be operated individually inside the repository container 10. It can be operated at the same time all heating panels 22 at the same time or selectively only a part of the heating panels 22nd

The primary cover 18, with which the opening 17 in the lid 15 of the repository container 10 can be closed, has at least one opening, specifically two openings 25, 26 in the exemplary embodiment shown. The opening 26 is preferably one for extracting moist air, which have been heated by the heating panels 22 in the interior 11 of the repository container 10. The other opening 25 serves to supply dry, cooler fresh air or room air into the interior of the repository container 10. Preferably, the openings 25, 26 are provided with connections for hoses for the supply and removal of air. If necessary, only one opening is sufficient if a single tube with several chambers is used to supply dry air and remove moist air. The openings 25, 26 are closed after completion of the drying by the secondary cover 19.

The process according to the invention for drying articles, in particular residues, in the disposal container 10 will be described in more detail below:
First, the interior 11 of the repository container 10 is loaded with the contaminated objects or residues to be accommodated therein. These items are usually still wet. After loading the repository container 10, the opening 17 is closed with the primary cover 18. When not yet connected to the side wall 13 cover 24 is now drying the contaminated residues in the interior 11 of the repository container 10. For this purpose, first external power cable with sockets under the cover 24 for powering the heating panels 22 are connected. Likewise, the hoses for supplying dry outside air and for removing heated warm exhaust air in the areas of the openings 25 and 26 of the primary cover 18 are connected. The hoses for extracting moist exhaust air can be acted upon by a vacuum pump or the like with negative pressure, preferably up to an internal pressure in the final storage container 10 between 10 mbar and 200 mbar, preferably 30 mbar to 50 mbar. The setting and monitoring or regulation of the negative pressure in the interior of the repository container 10 is effected by a metering valve, which is preferably associated with the vacuum pump. Fresh, dry outside air is preferably sucked into the interior 11 and heated, and moist exhaust air is sucked out of the interior 11. It comes to a vacuum drying of the contaminated, still moist objects in the interior 11 of the repository container 10th

By an appropriate control outside of the repository container 10, the drying of the contaminated objects or residues in the interior 11 of the Repository tank 10 selectively, in particular gradually. Initially, only the floor 12 associated heating panels 22 are operated. As a result, the moist contaminated objects are first heated on the ground, so that moist liquid rises to the top. Only later are the side walls 13 and end walls 14 associated heating panels 22 operated in a second step and thereby the contaminated objects also heated laterally. As a result, the residual moisture of the contaminated objects in the interior 11 is eliminated. This leads to a targeted drying of the contaminated objects in the repository container 10 by a rising from bottom to top expulsion of moisture from the contaminated objects or residues.

Drying is monitored for compliance with at least one drying criterion. This preferably takes place after a certain drying time, which according to experience leads to sufficient drying of the moist objects in the interior 11 of the repository container 10. However, it is also conceivable to carry out random checks of the drying criterion several times during drying or even to monitor the degree of drying continuously.

To determine the degree of drying and to check compliance with the at least one drying criterion, a shut-off valve is closed to the vacuum pump, namely at an internal pressure in the repository container 10, which is <20 mbar. After a waiting time of a few minutes, preferably about 5 minutes, the pressure rise within a certain time is preferably determined by a pressure gauge outside of the repository container 10. The drying criterion is met, ie the articles or residues in the interior 11 of the repository container 10 sufficiently dried when the pressure increase within a certain period of time does not exceed a predetermined value. For example, the pressure increase must not exceed 5 mbar within one hour. Preferably, the drying criterion is met if the pressure increase does not exceed 3 mbar within about 15 minutes.

If it is determined that at least one drying criterion is not met, drying is continued and the vacuum pump is put back into operation. After a certain period of subsequent drying, it is again determined whether the drying criterion is met.

After completion of the drying, which may take several days, the connections of the hoses and external power supply cables of the Receptacle 10 is separated and the secondary cover 19 is screwed over the primary cover 18 to the opening 17 to close the openings 25 and 26 in the primary cover 18. In addition, the lid 24 is screwed onto the side wall 13 to close the power cable penetrations through the side wall 13 or for covering the outlets. Now, the repository container 10 can be supplied with the therein contained dried contaminated objects or residues in remaining heating panels 22 of the final disposal, namely stored in the repository.

The disposal container 10 shown in the figures is further designed so that at least some walls, preferably all walls, namely side walls 13, end walls 14, the bottom 12 and the ceiling 15, are plugged together. For this purpose, the side walls 13, the end walls 14, the bottom 12 and the ceiling 15 are mutually associated with each other and correspondingly interlocking projections 27 assigned. The projections 27 and the grooves 28 have an approximately rectangular cross-section in the embodiment shown. The rectangular projections 27 and grooves 28 correspond in such a way that they intermesh with one another in a form-fitting manner without play (FIG. Fig. 4 ).

In the illustrated embodiment, the upper and lower horizontal end faces of the side walls 13 and the end walls 14 are each provided with a continuous elongated projection 27. Corresponding continuous grooves 28 are provided in longitudinal and transverse edge regions of both the floor 12 and the ceiling 15 ( Fig. 4 ). As a result, the bottom 12 and the ceiling 15 are positively connected to the side walls 13 and the end walls 14 plugged together ( Fig. 4 ). In addition, the vertical end faces of the end walls 14 are provided with projections 27 passing from top to bottom, which engage in corresponding grooves 28 in vertical edge regions of the side walls 13 ( Fig. 5 ). As a result, the side walls 13 and the end walls 14 can be plugged together in a form-fitting manner, wherein the narrower end walls 14 come to rest between the overlapping side walls 13 (FIG. Fig. 5 ).

The projections 27 and grooves 28 in the bottom 12, the ceiling 15 and in or on the side walls 13 and end walls 14 are arranged so that they after joining the side walls 13, the end walls 14, the bottom 12 and the ceiling 15 to the repository container 10 interlock form fit and clearance. As a result, the side walls 13, the end walls 14, the bottom 12 and the ceiling 15 take their intended relative positions one another, in which the mated parts of the repository container 10 can be welded together. At the same time, the parts of the repository container 10 are fixed relative to one another and thus held together during welding.

LIST OF REFERENCE NUMBERS

10

final disposal containers

11

inner space

12

ground

13

Side wall

14

bulkhead

15

blanket

16

Patch fitting

17

opening

18

primary cover

19

Secondary cover

20

screw

21

poetry

22

heating panel

23

cover plate

24

cover

25

opening

26

opening

27

head Start

28

groove

Claims (7)

1. Method for drying at least one contaminated object in a final storage container (10), the at least one object in the final storage container (10) being dried by internal heating of the final storage container (10) by means of a heater having multiple heating elements arranged in the interior of the same, characterized in that the heating is performed by selective operation of the heating elements, the at least one object being dried in multiple steps and moist air produced during the drying being extracted from the final storage container (10).
2. Method according to Claim 1, characterized in that extraction is carried out by means of negative pressure through at least one opening (25, 26) of the final storage container (10), which, in particular, can be closed after the drying.
3. Method according to Claim 1, characterized in that the at least one object in the final storage container (10) is dried by vacuum drying.
4. Final storage container for at least one contaminated object, having an internal space (11) for holding the at least one object, which internal space is formed by side walls (13), front walls (14), a bottom (12) and a top (15) having an opening (17) that can be closed by means of at least one cover (18, 19), and has multiple heating elements, characterized in that the heating elements are assigned to the inner side of the at least one of the side walls (13), the front walls (14) and/or the bottom (12) of the internal space (11), and the heating elements are formed as electric heating panels.
5. Final storage container according to Claim 4, characterized in that multiple electric heating panels are provided, which can be operated separately or together, in particular dependently on or independently of one another.
6. Final storage container according to Claim 4 or 5, characterized in that the electric heating panels are assigned at least one mechanical protective element, preferably the or each protective element is arranged in front of or above an inner side of the respective electric heating panels and/or the respective protective element is formed as a cover plate (23).
7. Final storage container according to one of Claims 4 to 6, characterized by a sandwich-like structure, preferably from outside to inside a steel wall, a concrete wall, a steel wall, the electric heating elements and at least one protective element.

Images