Repairing system as well as repairing method

Abstract

A repairing system (2) is used for applying an adhesive to a location to be repaired underwater in a container. The repairing system (2) comprises a movable and remotely controlled repairing robot (10) that is configured to be driven underwater. The repairing robot (10) comprises a repairing module (12) that is configured to be coupled with an adhesive applying module (34). The adhesive applying module (34) is configured to dispense an adhesive on the location to be repaired. Further, a repairing method is described.

Claims

1. A repairing system for applying an adhesive to a location to be repaired underwater in a container, the system comprising: a movable and remotely controlled repairing robot that is configured to be driven underwater, the repairing robot comprising a repairing module, the movable and remotely controlled repairing robot being constructed modularly, the repairing module being a central repairing module that provides respective interfaces for connecting further modules, the repairing module being configured to be coupled with an adhesive applying module, the adhesive applying module being configured to dispense an adhesive on the location to be repaired, the repairing module comprising two driving interfaces each configured to be coupled with a corresponding driving module having at least one wheel, which ensures the movability of the repairing robot; the repairing module being configured to be coupled with a cleaning module; and the repairing module having a functional interface configured to be coupled with the adhesive applying module and the cleaning module selectively.

2. The system of claim 1, wherein the cleaning module comprises at least one cleaning brush unit.

3. The system of claim 1, wherein the adhesive applying module comprises an appliance brush.

4. The system of claim 3, wherein the adhesive applying module has an outlet for dispensing the adhesive on the location to be repaired, and wherein the outlet is assigned to the appliance brush.

5. The system of claim 1, wherein the repairing module is configured to be coupled with a location finding module and/or a leakage determination module.

6. The system of claim 1, further comprising at least one camera module.

7. A repairing method to be performed underwater in a container using the repairing system as recited in claim 1, the method comprising: driving the movable and remotely controlled repairing robot underwater to the location to be repaired within the container; and applying an adhesive on the location to be repaired underwater, the adhesive being brushed on the location to be repaired underwater.

8. The repairing method according to claim 7, further comprising cleaning the location to be repaired prior to the appliance of the adhesive.

9. The repairing method according to claim 7, localizing the location to be repaired by using an Alternating Current Field Measurement (ACFM) technique and/or by determining an amount of leakage.

10. A repairing system for applying an adhesive to a location to be repaired underwater in a container, the system comprising: a movable and remotely controlled repairing robot that is configured to be driven underwater, the repairing robot comprising a repairing module, the movable and remotely controlled repairing robot being constructed modularly, the repairing module being a central repairing module that provides respective interfaces for connecting further modules, the repairing module being configured to be coupled with an adhesive applying module, the adhesive applying module being configured to dispense an adhesive on the location to be repaired, the repairing module comprising two driving interfaces each configured to be coupled with a corresponding driving module having at least one wheel, which ensures the movability of the repairing robot; and the adhesive applying module comprising a rotating appliance brush.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a schematic view of a repairing system according to the present disclosure,

(3) FIG. 2 shows a perspective view of a repairing robot used by the repairing system of FIG. 1,

(4) FIG. 3 shows another perspective view of the repairing robot shown in FIG. 2 wherein a suspension module and an adhesive supplying module is provided,

(5) FIG. 4 shows a bottom view of the repairing robot shown in FIG. 2,

(6) FIG. 5 shows another perspective view of the repairing robot shown in FIG. 2,

(7) FIG. 6 shows another perspective view of the repairing robot shown in FIG. 2,

(8) FIG. 7 solely shows the repairing module of the repairing robot of FIG. 2 in a perspective view,

(9) FIG. 8 shows another perspective of the repairing module of FIG. 7,

(10) FIG. 9 shows a perspective view of a driving module used by the repairing robot shown in FIG. 2,

(11) FIG. 10 shows another perspective view of the driving module of FIG. 9,

(12) FIG. 11 shows the repairing robot of the repairing system of FIG. 1 in another operation mode,

(13) FIG. 12 shows a bottom view of the repairing robot of FIG. 11,

(14) FIG. 13 shows another perspective view of the repairing robot of FIG. 11,

(15) FIG. 14 shows the repairing robot of FIG. 11 in a perspective view wherein the suspension module and the adhesive supplying module are provided,

(16) FIG. 15 shows a perspective view of the combined suspension module and adhesive supplying module,

(17) FIG. 16 shows another perspective view of the combined member shown in FIG. 15, and

(18) FIG. 17 shows another overview of the repairing robot of the repairing system according to the present disclosure illustrating the modular structure of the repairing robot.

DETAILED DESCRIPTION

(19) In FIG. 1, a repairing system 2 is shown that is used for performing repairs underwater.

(20) In the shown embodiment, the repairing system 2 is used in conjunction with a container 4 filled with a medium wherein a rack 6 is placed within the container 4. For instance, the container 4 corresponds to a (spent) fuel pool of a nuclear power plant such that the rack 6 is a rack of fuel elements (also called fuel rack). Hence, the medium within the container 4 corresponds to an acidic medium, for instance in a medium comprising boron acid.

(21) In the container 4, a location to be repaired 8 may be provided that has to be repaired by the repairing system 2 underwater, namely in the acidic medium. For instance, the location to be repaired 8 is located under the rack 6 so that the respective location 8 cannot be reached from the top of the container 4.

(22) The location to be repaired 8 may correspond to a corrosive location that reduces the wall thickness of the respective wall of the container 4, namely the bottom wall. Alternatively or additionally, a leakage may occur via which the medium may leak into the underground.

(23) The location to be repaired 8 may also correspond to a location with a mechanical damage and/or stress, for instance mechanical stress or rather thermal stress.

(24) Moreover, the location to be repaired 8 may be a location that is prone to a damage or failure in the future so that the respective location is repaired proactively or rather in a preventive manner.

(25) For repairing the location to be repaired 8, the repairing system 2 comprises a movable and remotely controlled repairing robot 10 that can be used for applying an adhesive to the location to be repaired 8 underwater in the container 4 as will be discussed later.

(26) The moveable and remotely controlled repairing robot 10 as well as its components are shown in FIGS. 2 to 17 in more detail.

(27) FIG. 2 reveals that the moveable and remotely controlled repairing robot 10 comprises a repairing module 12 that is connected with two driving modules 14 each comprising two wheels 16. As shown in FIG. 2, the wheels 16 of the driving modules 14 are established by Mecanum wheels ensuring a high movability of the repairing robot 10.

(28) The repairing module 12 is solely shown in FIGS. 7 and 8 wherein it becomes obvious that the repairing module 12 has two driving interfaces 18 being assigned to two opposite sides 20 of the repairing module 12. The driving interfaces 18 are configured to be connected with the driving module 14 each.

(29) The respective driving modules 14 are shown in FIGS. 9 and 10 solely. In these Figures, it becomes obvious that the driving modules 14 comprise corresponding interfaces 22 via which the driving modules 14 can be coupled with the repairing module 12, in particular the driving interfaces 18.

(30) For instance, the repairing module 12 comprises a drive such as an electric motor which is used for controlling the respective wheels 16 of the driving modules 14.

(31) Further, the repairing robot 10 comprises at least one camera module 24 that provides image so that the user of the repairing system 2 is enabled to observe the environment of the repairing robot 10 while the repairing robot 10 is driven underwater.

(32) For this purpose, the camera modules 24 each have at least one camera 26 being assigned to a moveable camera holder 28 which may be protected by a surrounding protection member 30 like a cage. The moveable camera holder 28 ensures that the at least one camera 26 can be moved, in particular swiveled or rotated, so that the environment of the repairing robot 10 can be observed in all dimensions.

(33) In the shown embodiment, the repairing robot 10 comprises two camera modules 24 wherein the camera modules 24 are assigned to the driving modules 14. Particularly, each driving module 14 comprises one camera module 24.

(34) The camera module 24 is located at a side of the driving module 14 being opposite to the interface 22 via which the driving module 14 is connected to the repairing module 12. Thus, the repairing module 12 is sandwiched between both driving modules 14 wherein the respective camera modules 24 face the outside of the repairing robot 10 so that the environment can be observed.

(35) The data related to the pictures recorded, in particular a video, are forwarded to the repairing module 12 via the respective interfaces 18, 22.

(36) In addition, the repairing module 12 has a control interface 31 which is configured to be connected with a separately formed control unit, for instance via wires, cables or any other suitable signal transmitting member-

(37) Moreover, the repairing module 12 has a functional interface 32 that is configured to be coupled with other modules, for instance an adhesive applying module 34 as shown in FIG. 2 illustrating an adhesive applying mode of the repairing robot 10.

(38) The functional interface 32 is assigned to a side of the repairing module 12 being substantially perpendicular to the sides 20 at which the driving interfaces 18 are located. Moreover, the functional interface 32 is opposite to the control interface 31.

(39) Accordingly, the control interface 31, the functional interface 32 as well as the driving interfaces 18 are each assigned to different sides of the repairing module 12.

(40) As shown in FIG. 2, the adhesive applying module 34 is connected with the repairing module 12 via two connecting members 36. The connecting member 36 may each comprise a bolt via which the adhesive applying module 34 is fixedly connected to the repairing module 12.

(41) In general, the adhesive applying module 34 is configured to dispense an adhesive on the location to be repaired 8. For this purpose, the adhesive applying module 34 comprises a hose 38 via which the adhesive to be applied is forwarded to an outlet 40 of the adhesive applying module 34; please refer to FIG. 4.

(42) Alternatively, the adhesive applying module 34 may comprise a tube, a sleeve and/or a pipe for forwarding the adhesive to be dispensed to the outlet 40.

(43) As shown in FIG. 4, the adhesive applying module 34 also comprises an appliance brush 42 that is formed in a substantially circular manner wherein three arc-shaped portions of the appliance brush 42 are provided. The appliance brush 42 is located in a concentric manner about the outlet 40 so that the radial distance between the outlet and the appliance brush 42 is substantially the same.

(44) The appliance brush 42 can be driven so that it rotates while the adhesive is applied to the location to be repaired 8 underwater. By doing so, the medium surrounding the location to be repaired 8 is pushed away due to the rotation of the appliance brush 42 so that the location to be repaired 8 is laid bare. Hence, it is ensured that the adhesive can be applied directly on the location to be repaired 8 improving the adhesion properties of the adhesive applied.

(45) Furthermore, the repairing robot 10 is moved forwards and backwards while the adhesive is applied to the location to be repaired 8 such that the adhesive is brushed in via the appliance brush 42.

(46) As shown in FIG. 4, the adhesive applying module 34 has an appliance surface 44 that is encircled by the appliance brush 42. The appliance surface 44 comprises the outlet 40 in its center.

(47) The appliance surface 44 may be curved with respect to the appliance level, for instance in a concave manner, so that a space between the wall comprising the location to be repaired 8 and the outlet 40 is provided due to the shape pf the curved appliance surface 44.

(48) In FIG. 3, it is shown that the repairing robot 10 comprises an adhesive supply module 46 that is positioned on top of the repairing robot 10 wherein the adhesive to be applied via the outlet 40 is supplied to the adhesive applying module 34 via the adhesive supply module 46. Therefore, the adhesive supply module 46 is fluidly coupled with the adhesive applying module 34.

(49) In the shown embodiment, the adhesive supply module 46 is connected to the driving modules 14 each having respective openings for accommodating the adhesive supply module 46 which becomes obvious in FIG. 2 as well as FIGS. 9 and 10. Hence, the adhesive to be applied is supplied to the respective interiors of the driving modules 14 which are fluidly coupled with the adhesive applying module 34 via the repairing module 12.

(50) The adhesive supply module 46 is established by a functional unit 48 that also comprises a suspension module 50 via which the repairing robot 10 is positioned within the container 4, for instance via a crane. Hence, the suspension module 50 ensures that the repairing robot 10 can be abseiled appropriately.

(51) The functional unit 48 may correspond to a common suspension and supplying unit since both functionalities are established by the common functional unit 48.

(52) The respective functional unit 48 is shown in more detail in FIGS. 15 and 16. These Figures reveal that the functional unit 48 is separately formed with respect to the repairing module 12 as well as the driving modules 14. The respective adhesive supply module 46 comprises adhesive supply elements 52 which are inserted into the driving modules 14 for supplying the adhesive to be applied as discussed above.

(53) In FIGS. 11 to 14, the repairing robot 10 is shown in another operating mode, namely a cleaning mode.

(54) In the cleaning mode, the adhesive apply module 34 is replaced by a cleaning module 54 that is connected with the functional interface 32 of the repairing module 12.

(55) Accordingly, the repairing module 12 is generally configured to be coupled with different modules, namely the adhesive applying module 34 as well as the cleaning module 54 depending on the operation mode of the repairing robot 10 as will be discussed later.

(56) In the cleaning operation mode, the repairing module 12 is also connected with the driving modules 14 in a similar manner as discussed with respect to the repairing robot 10 in the adhesive applying mode.

(57) Thus, the only difference between both operation modes is that the adhesive applying module 34 is replaced by the cleaning module 54.

(58) The cleaning module 54 comprises at least one cleaning brush unit 56 so that the location to be repaired 8 can be cleaned by brushing. Generally, the cleaning brush unit 56 may be used to clean the location to be repaired 8 prior to the appliance of the respective adhesive.

(59) As shown in FIG. 12, the cleaning brush unit 56 comprises three separate brushes 58 each being formed in a substantial circular manner wherein each brush 59 comprises three arc-shaped portions. Hence, each brush 58 of the cleaning brush unit 56 corresponds substantially to the appliance brush 42 of the adhesive applying module 34.

(60) The different brushes 58 can be controlled separately and/or commonly wherein the controlling of the brushes 58 may depend on a certain cleaning mode of the repairing robot 10.

(61) Irrespective of the cleaning module 54, the adhesive applying module 34 may also be used for cleaning purposes, in particular the respective appliance brush 42. Accordingly, the appliance brush 42 is rotated for cleaning purposes wherein no adhesive is dispensed when the adhesive applying module 34 is operated in a cleaning mode.

(62) During the cleaning process, the material brushed away may be sucked in by a suction member as well as a filter being connected to the suction member so that the material sucked in can be collected within the filter. For instance, the filter is also placed within the container 4 during the cleaning process.

(63) As already discussed, the repairing system 2 is generally used to repair a location to be repaired 8 underwater within the container 4, for instance a (spent) fuel pool of a nuclear power plant, in particular a location 8 that cannot be reached from the top of the container 4 as shown in FIG. 1.

(64) For doing so, the repairing system 2 uses the repairing robot 10 that is movable underwater and, therefore, remotely controlled by a control unit 60; please refer to FIG. 1.

(65) The control unit 60 is connected with the repairing robot 10 via its control interface 31 and appropriate cables or wires 62.

(66) The control signals as well as the signals from the repairing robot 10 may be transmitted via the cables or wires 62 so that a bidirectional communication is established.

(67) In addition, the repairing system 2 also comprises, besides the control unit 60, an adhesive mixing machine 64 which provides the adhesive to be applied.

(68) The adhesive mixing machine 64 as well as the control unit 60 are located outside of the container 4, for instance at a pool edge or a reactor floor next to the container 4 as shown in FIG. 1.

(69) The adhesive mixed within the adhesive mixing machine 64 is forwarded to the repairing robot 10 via a hose 66. Alternatively, a conduit, a pipe, a line or any other suitable member is used for supplying the adhesive.

(70) In fact, the adhesive is pumped by a pumping unit 68 of the adhesive mixing machine 64 to the repairing robot 10, in particular the adhesive applying module 46.

(71) The adhesive mixing machine 64, in particular its pumping unit 68, is also controlled by the control unit 60.

(72) In general, the moveable and remotely controlled repairing robot 10 is modularly structured so that several modules can be combined. This is shown in FIG. 17 wherein the modular structure of the repairing robot 10 is illustrated since several different modules of the repairing robot 10 are shown in an exploded view.

(73) The repairing module 12 is the central module (or main module) of the repairing robot 10 that has several interfaces 18, 31, 32 that can be used for interconnecting different modules such as the driving modules 14, the adhesive applying module 34, the cleaning module 54, a location finding module 70 and/or a leakage determination module 72. For instance, the location finding module 70 is established by an alternating current field measurement module (ACFM) module whereas the leakage determination module 72 is established by a vacuum box module.

(74) The respective modules can be coupled with the repairing module 12 simultaneously as shown in FIGS. 1 to 6 as well as FIGS. 11 to 14. Moreover, certain modules may be coupled subsequently as will be described hereinafter.

(75) The modular structure of the repairing robot 10 is inter alia ensured by using universal interfaces ensuring a high connectivity of the repairing module 12.

(76) Hereinafter, a repairing method is described in more detail that is performed underwater in the container 4 by using the repairing system 2 described above.

(77) At the beginning, the components of the repairing system 2 are provided at the pool edge or the reactor floor next to the container 4, for instance the (spent) fuel pool.

(78) Then, the modular structured repairing robot 10 is configured with respect to the desired operation mode, for instance a location finding mode, a leakage determination mode, a cleaning mode or an adhesive appliance mode.

(79) The first three operation modes, namely the location finding mode, the leakage determination mode and the cleaning mode, may be optional. Nevertheless, the whole repairing method encompassing all operation modes are described hereinafter.

(80) Thus, the location to be repaired 8 has to be identified at the beginning, for instance a corrosive location.

(81) For this purpose, the location finding module 70 may be connected with the repairing module 12, in particular via the functional interface 32.

(82) In addition, the driving modules 14 (with the camera modules 24) are coupled with the repairing module 12 via the driving interfaces 18 so that the movable and remotely controlled repairing robot 10 is established.

(83) The repairing robot 10, in particular the repairing module 12, is connected with the control unit 60 via the cables or wires 62 connected to the control interface 31 so that the repairing robot 10 can be controlled remotely.

(84) For placing the repairing robot 10 in the container 4, at least the suspension module 50 is connected with the repairing robot 10 so that the repairing robot 10 can be inserted into the container 4, for instance via a crane.

(85) Then, the repairing robot 10 is controlled so as to move within the container 4 underwater wherein the respective control signals are forwarded to the driving modules 14 so that the respective wheels 16 move forwards, backwards and/or in the desired direction.

(86) While the repairing robot 10 is driven within the container 4 underwater, the location finding module 70 checks the container 4, for instance the walls, welding spots and so on, in order to find and localize a critical location which should be repaired such as a corrosive location.

(87) For orientation purposes, the user can navigate the repairing robot 10 due to the video(s) and/or pictures (submitted) by the camera module(s) 24 while the repairing robot 10 is moving underwater.

(88) Once the corrosive finding module 70 identifies a location which might correspond to a leakage and/or a location having a reduced wall thickness (generally: a location to be repaired 8), the respective location is recorded so that it can be found again easily later.

(89) As mentioned above, the location to be repaired 8 may also correspond to a location that is repaired in a preventive manner.

(90) Then, the repairing robot 10 may be removed from the container 4 for replacing the location finding module 70 by the leakage determination module 72 in order to determine whether or not the location corresponds to a leakage. Therefore, the location finding module 70 is decoupled from the repairing module 12 which is coupled with the leakage determination module 72, in particular via the functional interface 32.

(91) However, the location finding module 70 and the leakage determination module 72 may be integrated so that a possible leakage can be identified right after the respective critical location was identified by the location finding module 70.

(92) Afterwards, the location to be repaired 8, which was identified previously, in particular with regard to a possible leakage, may be cleaned by the cleaning module 54 so that the location 8 is prepared for adhesive appliance.

(93) Thus, the repairing robot 10 may be removed (again) from the container 4 so that the cleaning module 54 can be coupled with the repairing module 12 via the functional interface 32. The repairing robot 10 is in a cleaning operation mode wherein, in the cleaning operation mode, the repairing robot 10 may substantially correspond to the repairing robot 10 shown in FIGS. 11 to 14.

(94) However, the location finding module 70 and/or the leakage determination module 72 may also be coupled to another interface than the functional interface 32 so that the repairing module 12 may already be coupled with the cleaning module 54 as well as the location finding module 70 and/or the leakage determination module 72 at the beginning.

(95) Hence, the location to be repaired 8 can be localized by the location finding module 70, a possible leakage is identified by the leakage determination module 72 and, afterwards, the location to be repaired 8 can be cleaned by the cleaning module 54 without lifting the repairing robot 10 out of the container 4.

(96) The repairing robot 10 with the cleaning module 54 coupled to the repairing module 12 is moved to the respective location to be repaired 8 in a remotely controlled manner.

(97) Once the repairing robot 10 reaches the location to be repaired 8 underwater, the cleaning module 54, in particular the at least one cleaning brush unit 56, cleans the location to be repaired 8 so that any deposits and/or residues are brushed away by the at least one cleaning brush unit 56, in particular the several brushes 58 of the cleaning brush unit 56. The deposits and/or residues are brushed away are sucked in by the suction member wherein the respective material is collected in the filter which might be emptied later.

(98) After the location to be repaired 8 was cleaned, the repairing robot 10 is (again or for the first time) lifted out of the container 4 (via the crane and the suspension module 50). Then, the cleaning module 54 can be decoupled from the repairing module 12 so that the adhesive applying module 34 can be connected to the repairing module 12 via the functional interface 32. Hence, the repairing robot 10 is in the adhesive appliance operation mode so that the repairing robot 10 substantially corresponds to the one shown in FIGS. 2 to 6.

(99) Afterwards, the repairing robot 10 is placed, in particular abseiled, in the container 4 and driven underwater to the respective location to be repaired 8 in a remotely controlled manner.

(100) Once the repairing robot 10 having the adhesive applying module 34 reaches the location to be repaired 8 which was cleaned previously, the adhesive to be applied is forwarded to the adhesive applying module 34 via the adhesive mixing machine 64 and the adhesive supply module 46 such that the adhesive is dispensed via the outlet 40 of the adhesive applying module 34 on the location to be repaired 8. The outlet 40 may be established by a (conventional) nozzle.

(101) During the dispensing of the adhesive, the at least one appliance brush 42 of the adhesive applying module 34 is driven so that the appliance brush 42 rotates. Hence, the medium surrounding the location to be repaired 8, for instance the acid medium, is pushed away by the rotating appliance brush 42. Thus, the location to be repaired 8 is laid bare which ensures that the adhesive can be directly applied on the location to be repaired 8.

(102) Moreover, the repairing robot 10 is controlled to move forwards and/or backwards during the adhesive appliance so that the appliance brush 42 comes in contact with the adhesive dispensed as well as the location to be repaired 8.

(103) Due to the movement of the repairing robot 10 and/or the rotation of the appliance brush 42, the adhesive is brushed in or brushed onto the location 8.

(104) For instance, the appliance brush 42 is rotated by 1 to 300 rounds per minute. However, the adhesive may also applied without rotating the appliance brush 42. Moreover, the repairing robot 10 has a velocity of 5 to 100 cm/min. The adhesive applied on the location to be repaired 8 may have a width of 100 to 200 mm. Further, the thickness of the adhesive applied on the location to be repaired 8 may vary between 0.5 and 10 mm.

(105) In general, the adhesive used may be a self-leveling adhesive, for instance a polymer adhesive, in particular an epoxy adhesive. The adhesive itself may be radiation resistant. Moreover, the adhesive may be a two-component adhesive being mixed prior to its application by the adhesive mixing machine 64. The adhesive mixing machine 64 may mix the adhesive to be applied by mixing at least a resin as well as a hardener (curing agent).

(106) Afterwards, the self-leveling adhesive is pumped by the pumping unit 68 of the adhesive mixing machine 64, for instance by a flow rate of 50 to 500 ml/min.

(107) In general, the self-leveling adhesive may be applied on the location to be repaired 8 when the repairing robot 10 moves backwards so that it is ensured that the repairing robot 10 is not driven over the location to be repaired 8 on which the adhesive has been applied previously.

(108) Furthermore, the appliance brush 42 can also be used as a cleaning brush so that the adhesive applying module 34 is also the cleaning module 54. Accordingly, the respective modules 34, 54 do not have to be interchanged improving the required time for repairing the respective location 8.

(109) For instance, the location to be repaired 8 is cleaned by the appliance brush 42 when the repairing robot 10 is driven forwards along the location 8, in particular a weld, wherein the appliance brush 42 is driven so as to rotate in order to remove the deposits and/or residues. Afterwards, the adhesive is applied by the adhesive applying module 34 when the repairing robot 10 is driven backwards.

(110) In general, the appliance brush 42 may not be rotated during the appliance of the adhesive.

(111) Alternatively to the separately formed adhesive supply module 46, the adhesive may be supplied directly to the adhesive applying module 34.

(112) Accordingly, the adhesive is applied on the location to be repaired 8 underwater wherein the repairing system 2 ensures that locations can be repaired which cannot be reached from the top of the container 4 since the remotely controlled repairing robot 10 is driven to the respective location 8, for instance a location under the rack 6 which cannot be accessed from the top of the container 4.

(113) In the shown embodiment, the repairing robot 10 is driven along the bottom wall of the container 4 wherein each and everywhere location assigned to the bottom wall of the container 4 can be accessed by the movable repairing robot 10.