FR2719698A1 - Machine for loading fuel assemblies into a nuclear reactor through a pool - Google Patents

Abstract

A machine for loading and unloading fuel assemblies in a pressurised water-cooled nuclear reactor whose lid is removed for the purpose, allowing access to the reactor core through a pool of water in whose floor the reactor vessel is located, comprises a carriage (15) movable horizontally over the pool to align vertically with different parts of the core. From the carriage depends an outer sleeve (16) coaxially enclosing a rotatable sleeve (17) which encloses a vertically movable shaft (18) with means at its lower end to grip fuel assemblies. An upper housing (24) rotating with sleeve (17) has a lid (19) which carries winch (20) by which shaft (18) is raised and lowered via a cable. Guide pulleys (31) mounted inside sleeve (17) engage ribs on shaft (18) to guide the shaft. A second shaft (47) carries a TV camera and is similarly guided for vertical movement by a second winch (49) so that the loading/unloading may be observed.

Description

 The invention relates to a machine for loading fuel assemblies into the core of a nuclear reactor comprising means for guiding and removable displacement of a movable mast.

 Nuclear reactors such as pressurized water nuclear reactors comprise a vessel which encloses the core of the nuclear reactor constituted by fuel assemblies and in which circulates, in service, the reactor coolant.

 The reactor core consists of fuel assemblies which are generally of a straight prismatic shape, which come to rest on a core support plate by means of their lower part or lower end piece and which are placed in a vertical arrangement. The fuel assemblies are juxtaposed and constitute a dense assembly in which each of the fuel assemblies is in contact with neighboring assemblies, in a network arrangement, by means of its end fittings and its spacer grids.

 The fissile combustible material contained in the assemblies is gradually consumed in the operating nuclear reactor, so that the fuel assemblies are gradually depleted in fissile combustible material and consequently undergo some wear.

 It is therefore necessary to periodically perform operations to reload the core of the nuclear reactor. These operations, which require shutdown and cooling of the nuclear reactor, are generally carried out on a fraction of the reactor core, so as to optimize the use of fuel.

 On the other hand, during the initial commissioning of a nuclear reactor, it is necessary to charge the core with new fuel assemblies constituting the first load of the nuclear reactor.

 The loading or reloading operations of a nuclear reactor are carried out under water, the tank cover being removed, from the upper level of the reactor pool, at the bottom of which opens the tank well.

 To carry out the loading and reloading operations, a machine is used for lifting and handling the fuel assemblies called the loading machine, which comprises horizontal guide means arranged above the upper level of the swimming pool and a carriage mounted movably on the guide means, in at least two directions of a horizontal plane, so as to be able to place means for gripping and lifting the fuel assemblies directly above each of the positions of fuel assemblies in the core of the nuclear reactor.

 The means for gripping and lifting the fuel assemblies comprise a movable internal mast provided with means for gripping a fuel assembly at one of its ends and means for guiding and moving the movable mast in a vertical axial direction, these means comprising a lifting device such as a winch carried by the carriage.

 To achieve the installation of fuel assemblies in the reactor core where these assemblies are placed contiguously along a network, it is necessary to have extremely precise handling and lifting means.

 In particular, the internal mast of the loading machine must make it possible to move the fuel assemblies in a perfectly defined vertical axial direction. For this, the movable internal mast of the loading machine generally comprises longitudinal slides which cooperate, during the movement of the internal mast, with sets of rollers having axes perpendicular to the axial direction of the internal mast along which the movement is carried out; the rollers which are carried by an element of the guide and displacement assembly are arranged in several assemblies aligned in directions parallel to the axis of the internal mast.

 The displacements in the axial direction, that is to say in the vertical direction of the movable mast for carrying out the operations of reloading the core are of very great amplitude and must be carried out with very great precision as regards alignment the direction of movement of the mobile mast with the axes of the positions of the assemblies in the core of the reactor being loaded.

 The sets of guide rollers of the movable mast carried by the axial direction element of the guide assembly which are very long, must have perfectly straight alignment axes and perfectly defined in orientation and position.

 Before the loading machine is put into service or even during use, it may be necessary to check and adjust the alignment of the roller mast guide means of the movable mast carried by the axial steering element which is generally in the form of a tubular barrel of cylindrical shape.

 These adjustments may be required in particular by an adjustment of the roller assembly of the guide means or by a deformation of the external barrel, for example following an impact.

 This operation, which is carried out in the reactor building, near the tank well, requires the installation of scaffolding in order to be able to access the different roller positions along the external drum.

 The adjustment is made by means of eccentrics which are arranged at each roller support which is accessible through an opening provided in the external barrel, at the level of the roller support.

 Such an operation which includes the assembly and disassembly of a scaffold may require a period of the order of 48 hours during which the loading machine is unavailable, which consequently extends the total duration of the reactor shutdown for reloading.

 In addition, the operations for adjusting the guide elements of the mobile mast of the loading machine inside the reactor pool require emptying of this part of the pool after the installation of a cofferdam.

 The object of the invention is therefore to propose a machine for loading fuel assemblies from the core of a nuclear reactor, inside a reactor vessel open at its upper end in the reactor pool, comprising means horizontal guide bars arranged above the reactor vessel and the swimming pool, a carriage mounted to move on the guide means, a movable internal mast comprising means for gripping a fuel assembly at one of its ends and a assembly and guide movement of the internal mast in a vertical axial direction comprising a lifting means carried by the carriage, this loading machine making it possible to carry out adjustments of alignment and straightness of the elements for guiding the internal mast and operations of repair of the guide and displacement assembly of the mobile mast in a simple manner and outside the nuclear reactor pool, without causing any extension ent the duration of the reactor shutdown for loading or reloading.

For this purpose, the guide and displacement assembly of the internal mast comprises
- a tubular fixed barrel of generally cylindrical shape resting on the carriage with its vertical axis,
- a tubular rotating barrel of generally cylindrical shape mounted inside the fixed barrel removably, in a coaxial and rotary arrangement around the axis common to the fixed barrel and the rotary barrel,
means for guiding the internal mast in the axial direction fixed on the internal surface of the rotating barrel, and
- A support for the lifting means fixed removably and integral in rotation with the rotating barrel.

 In order to clearly understand the invention, a description will now be given, by way of nonlimiting example, with reference to the appended figures, an embodiment of a loading machine according to the invention.

 Figure 1 is a schematic elevational view in section through a vertical plane of a tank and a swimming pool of a nuclear reactor and a loading machine of known type.

 Figure 2 is an axial sectional view along 2-2 of Figure 3, of a loading machine according to the invention comprising a guide assembly and removable movement.

 Figure 3 is a cross-sectional view of the loading machine, along 3-3 of Figure 2.

 In Figure 1, we see the pool 1 of a nuclear reactor in the bottom of which opens the well 2 of the tank 3 of the reactor containing the core 4 of the reactor consisting of fuel assemblies 5 of straight prismatic shape, resting on their lower end part on a core support plate and arranged vertically and juxtaposed.

 During the loading or reloading operations of the core 4 of the nuclear reactor, the vessel 3 is opened, so that the interior volume of the vessel 3 in which the core 4 is disposed is accessible from the upper part of the reactor pool 1 .

 The swimming pool 1 is filled with water up to an upper level 6 above which are arranged guide means 7 of the carriage 9 of the loading machine 8 of the reactor. The carriage 9 which carries an external barrel 10 for guiding a movable mast 12 for taking up and lifting the fuel assemblies 5 is a carriage with crossed movements in two perpendicular directions from the horizontal plane of the guide means 7, so as to be able to place the external guide barrel 10 and the loading mast 12 in a position plumb with any fuel assembly 5 of the core or any position of fuel assembly in the core.

 The external barrel 10 comprises means for guiding in the vertical axial direction of the internal mast 12 which is movably mounted in a coaxial arrangement inside the external barrel 10.

 The means for guiding the internal mast 12 carried by the external barrel 10 generally consist of sets of rollers distributed along the length of the external barrel 10 making it possible to guide the internal mast 12 in the vertical axial direction, between a raised position inside the external barrel 10 and a low position in which a hooking device 13 located at the lower end of the internal mast 12 is located at the upper end pieces of the assemblies 5 of the nuclear reactor core. In this low position, it is possible to take up or deposit an assembly 5 in the core 4 of the reactor.

 The internal mast 12 can be moved in the vertical axial direction between its raised position and its low position, by a winch 11 carried by the carriage 9 of the loading machine 8.

 Between its low position and its high position, the internal mast 12 is guided inside the external barrel 10 by guide elements carried by the external barrel 10 which are generally constituted by sets of rollers.

 The alignment of the sets of rollers of the guide elements determines the alignment and the direction of movement of the internal mast 12 and possibly of an assembly 5 fixed to the lower end 13 of the internal mast 12.

 The alignment of the sets of rollers must therefore be checked and adjusted very precisely before loading or recharging the core of a nuclear reactor.

 The verification and adjustment of the sets of rollers of the guide elements of the movable mast can be carried out on the external barrel 10 which remains permanently fixed on the carriage of the loading machine. These operations must therefore be carried out on the high external barrel 10 in a vertical position and inside the reactor building. The verification and adjustment of alignment of the guide means of the movable mast is therefore an operation which can be of long duration and which requires the installation of access means such as scaffolding around the vertical external barrel of the machine. loading.

 In the event that, during the loading or reloading of the nuclear reactor, there is a deterioration of the means for guiding the internal mast, resulting in a misalignment, it may be necessary to stop the loading or reloading operations. to repair or adjust the guide means on the external barrel.

 In this case, it is necessary to move the loading machine to an area of the reactor pool which must be drained after the installation of an insulation cofferdam, so that one can intervene on the guide elements integral with the barrel. of the loading machine.

 The charging machine can therefore remain unavailable for an extended period, which results in a very costly extension of the period during which the nuclear reactor is not available for the production of electricity.

 In FIGS. 2 and 3, a loading machine according to the invention is shown, generally designated by the reference numeral 14.

 The loading machine 14 comprises a carriage 15 mounted mobile on horizontal guide elements above the pool of a nuclear reactor, a first tubular barrel of cylindrical shape 16 carried by the carriage 15 called "fixed" barrel, a second tubular barrel 17 of cylindrical shape rotatably mounted inside the fixed barrel 16 and called "rotating" barrel, an internal mast 18 of cylindrical shape mounted movable in the vertical axial direction inside the rotating barrel 17 and a winch support 19 integral in rotation with the rotating barrel 17 carrying at least one hoist 20 for lifting the movable mast 18.

 The fixed barrel 16 comprises a tubular casing 16a and an annular support base 16b resting by means of adjustable support pads 21 on the carriage 15. Preferably, three support pads 21 can be used arranged at 1200 ° each other around the axis common to the ferrule 16a and to the annular support base 16b of the rotating barrel 16. Each of the support pads 21 has a central part 21a in the form of a wedge cooperating with two surfaces inclined by two parts of the shoe located on either side of the central part 21a.

 In this way, the verticality of the axis of the fixed shaft 16 resting by the support base 16b on the carriage 15 can be adjusted with very great precision, by displacement of the corners 21a.

 The annular support base 16b of the barrel 16 carries on its upper surface opposite the support pads 21, the outer ring 23a of a rolling bearing 23 whose internal ring 23b is integral with the lower part of a turret 24 of tubular shape ensuring the support and the connection in rotation of the rotating barrel 17 and of the support frame 19 of the winch 20.

 The rolling bearing 23 is fixed in a coaxial arrangement on the fixed shaft 16. In addition, the turret 24 and the rotating shaft 17 are arranged coaxially with respect to the fixed shaft 16.

 The vertical axis 25 is common to the fixed shaft 16, the rotating shaft 17, the bearing 23 and the turret 24 which are all coaxial. By means of the rolling bearing 23, the rotating barrel 17 resting on the turret 24 is rotatably mounted inside the fixed barrel 16, around the axis 25.

 The rotating barrel 17 rests by means of a flange 17a and of spring stops 26 on an internal lower part in the form of a flange of the turret 24. The turret 24 and the barrel 17 are thus secured in rotation around the axis 25 of the bearing 23 via which the turret 24 is rotatably mounted on the fixed shaft 16.

 The fixed shaft 16 carries on the internal surface of its tubular part 16a, in the vicinity of its lower end and in the vicinity of its upper end, respectively, a crown 27a and a crown 27b.

 As can be seen in FIGS. 2 and 3, the rotating barrel 17 carries, on the external surface of its tubular part, two sets of four stops respectively 28a and 28b arranged 90 "from each other around the axis 25 of the barrel 17 and facing the abutment crown 27a or 27b respectively. There is very little mounting clearance between the abutments 27a and 28a on the one hand and 27b and 28b on the other hand to ensure a holding and guiding the rotating barrel 17 inside the fixed barrel 16.

 The rotating barrel 17 which rests on the turret 24 is integral with the rotating turret and can be separated from the latter by simple lifting of the barrel 17 whose flange 17a carries lifting rings 29. In addition, the rotating barrel 17 can be slightly moved and oriented relative to the turret 24, thanks to the spring stops 26. This can ensure perfect adjustment of the verticality of the axis 25 of the rotating barrel 17 after its installation on the turret 24 rotatably mounted on the fixed shaft 16.

 As can be seen in FIG. 3, the rotating barrel 17 carries on its inner surface, roller supports 30 each carrying a set 31 of two rollers whose axes are perpendicular to each other and perpendicular to the axis 25 of the rotating barrel 17 .

 The supports 30 and the sets of rollers 31 are arranged in pairs opposite as shown in FIG. 3, so that an axial trace plane 32 in FIG. 3 constitutes a plane of symmetry common to the two sets of rollers 31 facing each other.

 To guide in the axial direction 25 of the internal mast 18, the rotating barrel 17 comprises several sets of two sets of rollers 31 arranged opposite, as shown in FIG. 3.

 The mast 18 can be guided for example by five sets of two sets of rollers 31 arranged opposite as shown in FIG. 3, spaced apart from each other, in a regular manner, along the axial length of the rotating barrel 17.

 The internal mast 18 comprises two guide rails 33a and 33b fixed on its external surface in an axial direction and comprising two bearing surfaces at 90 "intended to come into contact with the rolling surfaces of the rollers of the games 31. thus effective guidance of the mast 18 during its movements in the vertical axial direction 25.

 The support frame 19 of the winch 20 comes to rest on an upper support flange of the turret 24 on which it is fixed by retaining screws 34.

 By unscrewing the retaining screws 34, it is possible to separate the support frame 19 from the turret 24 and ensure its lifting by means of lifting rings 35.

 The winch 20 is associated with a lifting pulley 36 rotatably mounted on a suspension head 37 of the internal mast 18, a deflection pulley 38 rotatably mounted under the support frame 19 and with a load compensating counterweight 39 disposed above the 'a rim 19' constituting the lower part of the support frame 19. The cable 40 of the winch 20 which is wound at one of its ends on the winch drum and which is connected at its other end to the counterweight 39 passes successively over the lifting pulley 36 and on the return pulley 38. The operation of the winch 20 makes it possible to move the mast 18 in the vertical axial direction 25, the mast 18 being guided by the sets of rollers 31 cooperating with the rails 33a and 33b. The internal mast 18 has at its lower part a device 41 for hooking a fuel assembly 42 which is shown partially and in dotted lines in FIGS. 2 and 3.

 The loading mast according to the invention further comprises two guiding devices 43 and 43 'of the lower part of a fuel assembly 42, when it is placed in the core.

 One of the devices 43 is shown in an out of service position and the other device 43 'in a service position.

 The device 43 comprises a very long rod 43a provided with hooking means 43b on brackets integral with the inner surface of the rotating barrel 17 and a guide block 43c at its lower end.

 On the outer surface of the internal mast 18 are also arranged attachment brackets for fixing a guide device such as 43 on the mobile mast 18, in a service position.

 In FIG. 3, the guide device 43 'has been shown in its service position against the external surface of the movable mast 18.

 In this position, the lower guide portion of the device 43 'is at a level such that it can maintain and guide the lower end of the assembly 42, when it is deposited on the plate. bottom of the core, inside the nuclear reactor vessel.

 The devices such as 43 and 43 ′ can be moved between their out-of-service position and their service position by means not shown, fixed on the upper part of the rotating barrel 17.

 On the inner wall of the rotating barrel 17 is also mounted articulated, about an axis 45, a stop 44 for holding a fuel assembly 42.

 The stop 44 can be moved between an out-of-service position shown in FIGS. 2 and 3 and a service position in which the stop 44 engages inside the lower end piece of a fuel assembly suspended from the end of the mast 18 by means of the attachment device 41, when the mast 18 is in the fully raised position, the assembly 42 then being fully engaged inside the rotating barrel 17.

 It is thus possible to make displacements of the fuel assembly which is engaged inside the rotating barrel 17 and therefore protected against shocks, by using the loading machine whose carriage 15 moves on the horizontal guide means above from the fuel pool. During its movements, the assembly is maintained and immobilized by the stop 44 in the service position.

 The loading machine further comprises a video camera fixed to the end of a mast 47 suspended by means of a pulley 48 from the cable 50 of a lifting winch 49 resting on the support frame 19. As is visible in FIG. 3, rollers 51 rotatably mounted on supports 52 fixed to the inner surface of the rotating barrel 17 make it possible to guide the mast 47 of the video camera, during its movements in the vertical direction. The mast 47 has, on its external surface, in its axial direction, profiled rails 47a intended to cooperate with the groove of the rollers 51.

 Several sets of rollers are placed along the height of the barrel 17, so as to ensure effective guidance of the mast 47.

 The video camera fixed to the end of the mast 47 makes it possible to view the intervention area of the mast 18, during the removal or taking of fuel assemblies in the reactor core.

 Projectors associated with the mobile mast 18 make it possible to illuminate the intervention area.

 The video image of the intervention zone is displayed on a screen located at the cockpit of the loading machine, above the level of the reactor pool.

 At the end of a loading or reloading operation in the core of the nuclear reactor, the guide and displacement assembly of the movable mast 18 is dismantled.

 To do this, firstly, the supporting frame 19 is separated from the winches 20 and 49 from the turret 24, by unscrewing the screws 34. The masts 18 and 47 are rested on stops linked to the barrel 17, then the suspension pulleys 36 and 48 of the masts 18 and 47.

 The support frame 19 and the winches 20 and 49 can be separated from the loading machine by lifting the support frame 19 by means of the lifting rings 35.

 It is then possible to carry out the lifting and separation of an assembly comprising the rotating barrel 17 of the loading machine with the masts 18 and 47, the guide devices 43 and 43 ′ and the stop 44, by fixing lifting hooks of the pole bridge on the lifting rings 29 of the rotating barrel 17.

 The rotating drum 17 can be removed from the reactor building and placed in a workshop, in a position making it possible to easily carry out an intervention for the repair or adjustment of the sets of guide rollers 31 of the mast 18.

 It is thus possible in particular to align or realign the sets of rollers, in order to very precisely adjust the direction of movement of the mast 18 inside the rotating barrel 17.

 It is obvious that it is also possible to carry out the control and adjustment of the sets of rollers 51 ensuring the guidance of the mast 47 of the video camera.

 It is therefore possible to carry out, under very good conditions, in a specially installed workshop, the verification and adjustment of the guide elements placed inside the rotating barrel 17.

 It is also possible to carry out the repair or the adjustment of the other elements associated with the rotating barrel 17 for maintaining or guiding the assembly, such as the devices 43 and 43 'and the stop 44.

 One could also carry out the checks and adjustments of the elements associated with the rotating drum 17, inside the reactor building, insofar as one would have a room for these operations. This avoids having to take out the rotating drum 17 of the reactor building after a loading or reloading campaign of the reactor.

 It is also possible to carry out verification, adjustment and repair operations on the lifting assembly of the masts 18 and 47 comprising the winches 20 and 49.

 It is obvious that all repairs and adjustments can be made outside the reactor building, which is an important advantage in terms of intervention times.

 During the operation of the reactor, between two loading or reloading campaigns, only the carriage 15, the fixed drum 16 and the turret 24 of the loading machine must be kept assembled and in position on the guide rails of the loading machine .

 Prior to a new loading or reloading operation of the nuclear reactor, the guide and displacement assembly of the mobile mast must be put in place inside the fixed barrel and the turret which have remained in place inside the reactor building.

 For this, the rotating barrel 17 with the masts 18 and 47, the guide devices 43 and 43 'and the stop 44 are supported by a lifting means such as the polar bridge of the nuclear reactor via the rings of lifting 29 and introduced axially inside the fixed barrel '6, until it comes to rest, by means of the collar 17a, on the spring stops 26. The centering of the rotating barrel 17 inside the fixed barrel 16 is provided by the sets of stops 28a and 27a.

 The rotating barrel 17 which is replaced inside the fixed barrel of the loading machine comprises sets of rollers perfectly adjusted as to their alignment, so that a direction of movement of the movable mast is ensured which is perfectly determined and perfectly settled.

 Then the set of displacement of the masts 18 and 47 is put in place with the support frame 19 comprising winches 20 and 49.

 For this, the support frame 19 is attached to the polar bridge of the nuclear power station by means of the lifting rings 35.

 The support frame 19 is deposited on the upper part of the turret 24 and fixed in place by means of the screws 34.

 The loading machine is then ready to carry out a new loading or reloading operation of a nuclear reactor.

 An important advantage of the loading machine according to the invention is that the alignment of the guide rollers can be adjusted during the operation of the reactor, when the loading machine is not used. A significant time saving is thus obtained, during a unit shutdown, the adjustment operation of the loading machine being located on the critical path.

 This can be done without having to empty the reactor pool or install scaffolding. This considerably reduces downtime.

 In addition, the adjustment operations of the guide elements of the movable mast are carried out under better conditions than in the case of the prior art where these adjustments had to be made, in an area of the reactor pool isolated and drained, the element of the loading machine in which the mobile mast moves being in a vertical position.

 In the event that an incident occurs during the loading or reloading operation, for example a misalignment of the sets of guide rollers of the movable mast 18, it is possible to disassemble the rotating barrel 17 and separate it from the loading, after disassembly of the displacement and lifting assembly fixed on the support frame 19.

 We can then carry out the repair or adjustment of the guide elements of the rotating drum 17, either inside the reactor building, or outside after transporting the rotating drum 17 carrying the guide elements, in an intervention area. .

 It is also possible to carry out repairs or adjustments on elements different from the guide elements of the mobile mast.

 The loading machine according to the invention can therefore be used in all cases under very good operating conditions.

 In the case of a power station comprising several reactors, having loading machines of the same type, it is possible to use a single guide and removable displacement assembly which is successively mounted chassis supporting the winches can rest for example directly on the rotating drum.

 One can also imagine a mounting of the fixed barrel on the carriage of the loading machine different from that which has been described.

 The loading machine according to the invention can be used to perform loading or reloading operations of nuclear reactors of very different types.

Claims (10)

 1.- Machine for loading fuel assemblies (5, 42) from the core (4) of a nuclear reactor, inside a reactor vessel (3) open at its upper end in the pool (1) of the reactor, comprising horizontal guide means (7) disposed above the vessel (3) and of the reactor pool (1), a carriage (9, 15) mounted movably on the guide means (7), an internal mast (18) comprising gripping means (41) of a fuel assembly (42) at one of its ends and an assembly for guiding and moving the internal mast (18) in a vertical axial direction carried by the carriage (15), comprising a lifting means (20), characterized in that the assembly for guiding and moving the internal mast (18) comprises  - a fixed tubular barrel (16) of generally cylindrical shape resting on the carriage (15) with its vertical axis (25),  - a generally cylindrical rotating barrel (17) mounted inside the fixed barrel (16) removably in a coaxial and rotary arrangement around the axis (25) common to the fixed barrel (16) and to the barrel turning (17),  - means for guiding (30, 31) the internal mast in the axial direction fixed on the internal surface of the rotating barrel (17), and  - A support (19) of the lifting means (20) removably mounted and integral in rotation with the rotating barrel (17).  2.- loading machine according to claim 1, characterized in that it comprises a tubular turret (24) of cylindrical shape rotatably mounted about a vertical axis (25) on the fixed barrel (16) comprising means d support (26) for the support of the rotating barrel (17) and a support surface for the support and fixing of the support frame (19) of the lifting means (20).  3.- loading machine according to any one of claims 1 and 2, characterized in that it further comprises guide means (51, 52) of a mast (47) for moving a video camera fixed on the inner surface of the rotating barrel (17) in the axial direction (25).  4.- loading machine according to any one of claims 1 to 3, characterized in that it further comprises, guide means (43, 43 ') for the removal of a fuel assembly (42) resting on support brackets fixed on the inner surface of the rotating barrel (17).  5.- loading machine according to any one of claims 1 to 4, characterized in that it further comprises a pivoting stop (44) for holding a fuel assembly (42) fixed on the inner surface of the barrel turning (17).  6.- loading machine according to any one of claims 1 to 5, characterized in that the fixed barrel (16) carries on its inner surface at least two stops (27a, 27b) and that the rotating barrel (17) carries on its outer surface at least two stops (28a, 28b) in positions opposite the stops (27a, 27b) fixed on the inner surface of the fixed barrel (16).  7.- loading machine according to any one of claims 1 to 6, characterized in that the rotating barrel (17) comprises at least two lifting rings (29) fixed on an upper support part (17a) of the bole (17).  8.- loading machine according to any one of claims 1 to 7, characterized in that the support (19) of the lifting means (20) comprises lifting rings (35).  9.- loading machine according to any one of claims 1 to 8, characterized in that the support (19) of the lifting means (20) of the movable mast (18) carries a second lifting means (49) d 'a mast (47) for supporting a video camera.  10.- loading machine according to any one of claims 1 to 9, characterized in that the fixed barrel (16) rests on the carriage (15) by means of at least three support devices (21 ) in positions distributed around the axis (25) of the fixed shaft (16), each comprising a wedge-shaped part (21a), so as to adjust the height of the support devices (21) and the verticality of the axis (25) of movement of the internal mast (18).