Device for Cleaning the Cover Flange of the Reactor Vessel in a Nuclear Plant

Abstract

A device for cleaning the cover flange of the reactor vessel in a nuclear plant includes a pull arrangement for moving the device in translation along the perimeter of the flange, and an arrangement for removing dirt from the flange, the device being formed mainly by: a central body provided with a dirt removal device, the central body including an outer casing having a front support and a rear support attached thereto; a front wheel assembly supporting a front wheel support; a rear wheel assembly supporting a rear wheel support; a device for adjusting the angular position of the front wheel support in relation to the central body; and a device for adjusting the angular position of the rear wheel support in relation to the central body, and the central body is provided with a floating inner body.

Claims

1. An apparatus for cleaning a sealing flange of a vessel of a reactor of a nuclear power plant, comprising: a drive for moving the apparatus along a perimeter of the flange; an arrangement for dislodging any dirt lying on that flange; a central body, provided with an arrangement for wiping off the dirt, said central body comprising an outer casing which has a front support and a rear support fixed to the outer casing; a front train holding a front wheel support; a rear train holding a rear wheel support; an adjustment device for adjusting an angular position of the front wheel support in respect of the central body; and an adjustment device for adjusting an angular position of the rear wheel support in respect of the central body.

2. A cleaning apparatus, according to claim 1, wherein: at least one of the front train and the rear train is made up of a support including at least one plate forming a bracket, said bracket holds a motor for driving at least one of the front and rear wheel supports which are respectively arranged in vertical position, and the at least one of the front and rear wheel supports constitutes a moving part which is fitted under the at least one of the front and rear supports respectively and is adapted to rotate in respect of said support.

3. A cleaning apparatus, according to claim 2, wherein each adjustment device includes at least one screw held to the moving part, each of which is placed on one side of a rotation axle of the front support, in which each screw limits rotation of the front support in one rotation direction when the screw rests against a corresponding stop arranged in the fixed part.

4. A cleaning apparatus, according to claim 3, wherein the stop of each screw is one of the front wall and the rear wall, respectively, of the central body.

5. A cleaning apparatus, according to claim 1, wherein at least one of the front wheel support and rear wheel support hold respective front and rear drive rollers which are divided into two parts, and further comprising a body for transmitting movement placed between these two parts.

6. A cleaning apparatus, according to claim 5, wherein one of the two parts into which the front and rear drive rollers are divided is of greater width than the other part.

7. A cleaning apparatus, according to claim 1, wherein the central body comprises a floating inner body, said floating inner body holding the arrangement for wiping off the dirt, and said floating body is joined to the outer casing of the central body so as to allow relative vertical displacement therebetween.

8. A cleaning apparatus, according to claim 7, wherein the floating inner body is provided with a guiding device over a casing thereof, and the outer casing is provided with guides for interacting with the guiding device to guide the floating inner body.

9. A cleaning apparatus, according to claim 8, wherein the guiding device between the floating inner body and the outer casing is provided with an arrangement for securing the floating inner body in a desired relative position.

10. A cleaning apparatus, according to claim 7, wherein a connection between the floating body and the outer casing is provided with an arrangement for adjusting tension between the floating body and the outer casing.

11. A cleaning apparatus, according to claim 1, wherein the arrangement for wiping off the dirt includes a pair of front and rear cleaning rollers driven by respective motors, with mutually inverse movement, so that both rollers wipe the dirt off a floor towards a space between the rollers.

12. A cleaning apparatus, according to claim 1, wherein the outer casing of the central body is formed of lateral plates, a front plate, a rear plate and an upper plate, joined together by one of screws and tabs.

13. A cleaning apparatus, according to claim 7, wherein lateral plates forming the outer casing of the central body are provided with holes through which drive motors of cleaning rollers emerge, said holes substantially each having the form of a vertical slotted hole and are dimensioned in such a way that said drive motors can move vertically from an upper end position of the floating inner body in respect of the outer casing to a lower end position of said floating inner body.

14. A cleaning apparatus, according to claim 7, wherein the floating inner body also comprises a suction bell having an absorption inlet located between a pair of cleaning rollers.

15. A cleaning apparatus, according to claim 14, wherein the floating inner body also comprises a suction pump connected to the suction bell.

16. A cleaning apparatus, according to claim 15, wherein at least one lateral plate forming the outer casing of the central body is provided with a support for a particle filter, and the support for the particle filter is connected to the suction pump by a bellows-type conduit.

17. A cleaning apparatus, according to claim 16, further comprising a particle filter, which is located on a side of the central body closest to a center of the vessel, and having a free end located at a lower height than an end for joining to a corresponding support.

18. A cleaning apparatus, according to claim 14, wherein the suction bell is provided with a connection for an external suction inlet.

19. A cleaning apparatus, according to claim 11, wherein lateral plates forming the outer casing of the central body are provided with holes for access to roller axles, and the cleaning rollers are provided with the roller axles removable from at least one of the lateral plates, through said holes.

20. A cleaning apparatus, according to claim 1, wherein at least one of the front and rear wheel supports is provided with a probe which adjusts the distance from the central body to an inner edge of the sealing flange.

21. A cleaning apparatus, according to claim 20, wherein the probe includes a wheel held on a vertical axis and placed on a slotted support and adapted to be adjusted in different positions along said slotted support.

22. A cleaning apparatus, according to claim 21, the slotted support is provided with a graduated scale.

23. A cleaning apparatus, according to claim 1, wherein the central body is provided with spotlights for lighting.

24. A cleaning apparatus, according to claim 1, wherein the central body is provided with at least one camera for taking pictures.

25. A cleaning apparatus, according to claim 1, wherein an upper plate of the outer casing of the central body is provided with a set of coupling lugs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to illustrate the following explanation, we are enclosing . . . pages of drawings with this descriptive report in which six figures represent as an example, without constituting any limitation thereby, one form of embodiment of this invention, and in which:

[0031] FIG. 1 shows an exploded view of a dismantled detail of the cleaning apparatus according to the invention;

[0032] FIG. 2 shows a perspective view of the assembled apparatus of FIG. 1

[0033] FIG. 3 shows a view from the outer side (the one furthest from the rotation centre) of the apparatus of FIG. 1;

[0034] FIG. 4 shows a view from the inner side (the one closest to the rotation centre), of the apparatus of FIGS. 1 and 2;

[0035] FIG. 5 shows a view from an oblique viewpoint on the horizontal plane in which one can appreciate the front/rear train (according to the movement direction) and corresponding drive rollers or wheels, as well as the mechanism for transmitting the movement from the corresponding motor to said rollers;

[0036] FIG. 6 shows a lower view of the apparatus according to the invention in which one can appreciate the degree of tilt of the front and rear wheels; and

[0037] FIG. 7 shows an extended detail of the front train.

[0038] The following reference numbers can be appreciated in these figures: [0039] 1 central body [0040] 2 front support [0041] 3 rear support [0042] 4 front drive wheels or rollers [0043] 5 rear drive wheels or rollers [0044] 6 drive motor for the front rollers [0045] 7 drive motor for the rear rollers [0046] 8 transmission element for the front rollers [0047] 9 transmission element for the rear rollers [0048] 10 rotary support for the front rollers [0049] 11 rotary support for the rear rollers [0050] 12 devices for adjusting the angular position [0051] 13 lighting devices [0052] 14 cleaning rollers [0053] 15 outer anchorages or coupling hitches; lugs [0054] 16 particle filter [0055] 17 probe assembly [0056] 18 suction bell [0057] 19 suction pump [0058] 20 support for the particle filter [0059] 21 floating inner body [0060] 101 right-hand lateral plate of the outer casing of the central body (seen from behind looking forward) [0061] 102 left-hand lateral plate of the outer casing of the central body (seen from behind looking forward) [0062] 103 upper plate of the outer casing of a central body [0063] 104 rear plate of the outer casing of the central body [0064] 105 front plate of the outer casing of the central body [0065] 106 holes in the outer casing for the axles of the cleaning rollers [0066] 107 hole in the outer casing for the filter conduit [0067] 108 hole in the outer casing of the drive motors for the cleaning rollers [0068] 130 guiding devices for the floating body in the outer casing of the central body [0069] 141 drive motors for the cleaning rollers [0070] 142 axles for the cleaning rollers [0071] 171 probe support [0072] 172 slot for holding the probe [0073] 173 probe wheel or roller [0074] 211 right-hand lateral plate of the floating inner body [0075] 212 left-hand lateral plate of the floating inner body [0076] 213 upper plate of the floating inner body [0077] 214 rear plate of the floating inner body [0078] 215 front plate of the floating inner body [0079] 230 guide devices for the outer casing of the central body in the floating inner body

DESCRIPTION OF THE PREFERENTIAL FORMS OF EMBODIMENT

[0080] An apparatus for cleaning the sealing flange of the vessel of the reactor of a nuclear power plant is described, made up of a central body (1) which houses the cleaning media, and which also comprises front and rear trains made up of respective front (2) and rear (3) supports which hold the front and rear drive media respectively.

[0081] The drive media consist of front (4) and (5) drive wheels or rollers respectively, which are driven by respective motors (6,7), through the corresponding transmission elements (8,9).

[0082] The front (2) and rear (3) supports are made up of a plate or set of plates forming a bracket or fixed part. The motors (6,7) are placed in a fixed arrangement in said front (2) and rear (3) supports. The front (2) and rear (3) supports hold the front (10) and rear (11) wheel supports. These wheel supports are held in such a way as to be able to turn around a vertical axis, for appropriate positioning and control of the turning radius. The wheel supports (10,11) also have means for adjusting and setting the angular position in respect of the front (2) and rear (3) supports. When the apparatus has to be placed over the flange to proceed to clean this, the annular part of the flange that has to be cleaned will have to be determined, adjusting the inclination of the front and rear wheel supports for their travel to adapt to the item that has to be cleaned. To set the angular position of the wheel supports (10,11) there are devices for adjustment of the angular position (12), and specifically setting screws; more specifically still, it has been designed for said devices for adjusting the angular position to be pairs of setting screws, in which one of these will limit rotation in one direction and the other in the opposite direction. The setting screws are held in a wheel support (10,11) into which these are screwed and whose end can move back or forward, and act against a corresponding stop in the central body (1) or in the front or rear supports (2,3). According to a specific embodiment, the stop consists of one of the walls of the central body (1).

[0083] In accordance with a specific embodiment, the drive wheels (4,5) are divided into two portions of different length, and the corresponding transmission bodies (8,9) transmit the movement to the axle of said rollers (4,5) from the connecting zone of these portions (central, if these are identical). This asymmetry means that the drive motors (6,7) can be more satisfactorily located in the ideal position.

[0084] The front wheel support (10) and/or the rear wheel support (11) are provided with a probe (17) which regulates the distance of the apparatus to the inner edge of the flange. In a preferential embodiment the probe (17) consists of a wheel or roller (173) rotating on a vertical axis which is held in a support (171). This support is provided with a slot (172) along which the probe wheel (173) can be secured in position, this position determining the greater or lesser distance to the edge of the flange in the cleaning travel. This support may be provided with a graduated scale. As the device moves forward in its cleaning travel, the probe will correct or prevent any outward deviation.

[0085] Insofar as the motors (6,7) for powering the drive rollers (4,5) are independent, it has been seen that altering the speed of one of these in respect of the other corrects the trajectory, either getting closer to the edge, when the speed of the front one is greater, or moving away from this when the speed of the rear one is greater.

[0086] According to one form of preferential embodiment the central body is made up of two bodies, an outer casing (which is the visible part of the central body) and a floating inner body (21).

[0087] The central body (1), and particularly the floating inner body (21) contained in this, holds: [0088] the cleaning media, and particularly a pair of cleaning rollers (14) which move in the opposite rotation direction, moving the dirt from the floor towards the space lying between them; [0089] the drive motors of the cleaning media; [0090] a suction bell (18), whose suction mouth is located in the space lying between the cleaning rollers (14); [0091] a suction pump (19), according to one form of embodiment, or a mouth for a suction conduit, according to another form of embodiment.

[0092] The floating inner body (21) is made up of a box open at the bottom, consisting of a front plate (215), a rear plate (214), and lateral plates (211,212), as well as an upper plate (213), provided with attachment media by means of screws and/or tabs. The supports of the cleaning rollers (14) and their drive motors (141) are located between the lateral plates, and normally the upper plate (213) will hold the suction bell and the suction pump (19).

[0093] The front (215) and rear (214) plates have, in a particular embodiment, guiding devices (230) in respect of the outer casing.

[0094] Hence, the floating inner body (21) is able to move (in a vertical direction) in respect of the outer casing, which enables it to adapt to any small steps, if there were any, and to adjust the relative position in accordance with the wear of the wheels. The force at which the cleaning rollers (14) press on the surface to be cleaned will be that of the weight of the floating inner body (21), although said weight may be adjusted or corrected with additional weight, or reduced with floats or sustaining springs to increase or limit the force which the cleaning rollers (14) exert on the floor to be cleaned. This allows the force of incidence on the floor, and thus the cleaning effectiveness, to be independent of the degree of wear of the brushes. Securing media for the relative position between the floating inner body (21) and the outer casing have nevertheless been designed.

[0095] The outer casing is, according to a specific embodiment, made up of lateral plates (101,102) a front plate (105) a rear plate (104) and an upper plate (103), joined together by screws and/or tabs. The outer casing also takes the form of a prismatic box open at the bottom. The front (105) and rear (104) plates are internally provided with different guiding devices (130) complementary to the ones located (230) in the floating inner body (21).

[0096] The lateral plates (101,102) are provided with holes (106) giving access to the axles (142) of the cleaning rollers (14) and through which these axles (142) can be dismantled and extracted, and with them the cleaning rollers (14).

[0097] Furthermore, at least one of the lateral plates (101,102), and especially the one facing towards the centre of the reactor vessel, is provided with holes (108) through which the drive motors of the cleaning rollers emerge. Since the floating inner body (21) is vertically mobile in respect of the outer casing, these holes (108), must enable the displacement of the motors which are joined to the floating inner body, for which reason these holes (108) substantially have the shape of a vertical slotted hole and are dimensioned so that those motors can move vertically in these from an upper end position of the floating inner body in respect of the outer casing to a lower end position of said floating inner body (21).

[0098] Between the outlet of the suction pump (19) located in the floating inner body (21) and the outer casing there is a bellows-type conduit, which will absorb the variations in relative position, and will enable the debris collected to be taken towards a particle filter (16). The particle filter (16) is placed at the end of a support (20) which is fixed and held on the outer casing.

[0099] The support is arranged so that the particle filter (16) is located on the side of the central body closest to the centre of the vessel and whose free end is located at a lower height than the end for connection with the support (20) which holds this; this means that there is a lower risk of releasing particles such as radioactive particles outside the filter during dismantling operations.

[0100] The apparatus is provided with one or more spotlights, as well as one or more cameras for picking up images, and preferably also means for transmitting images. This enables the situation before and behind the cleaning operation to be observed, determining with greater reliability whether this needs to be gone over again or whether the process can be taken as finished. In accordance with a particular embodiment, the spotlights are located on the front (2) and rear (4) supports, as well as the camera or cameras for taking pictures.

[0101] The upper plate of the outer casing of the central body is provided with a set of coupling lugs (15).

[0102] Obviously anything to do with the arrangement of the floating inner body over the outer casing can also be embodied in a single central body within the scope of the invention.