SE503817C2 - Loading of nuclear fuel rods - Google Patents

Abstract

In the charging station, the fuel rods are arranged in guide grooves forming rows and a measuremnet unit measures the length and wt. of each row. The rows are loaded into encapsulating tubes by means of automatically working, individually manoeuvrable pushers via a guide arrangement. Several plates provided with rod rows load the encapsulating tubes arranged in a column with individual correct zone lengths and in accordance with the following stages:- a) fuel rods of different types are put into the feed stations, one for each type, b) an empty mobile plate is transported automatically to the stawtions for transfer of the rods, c) all or parts of the rods with correct individual length are placed on the plates, d) the transfered rod rows individual length and wt. are measured, the measurements are recorded so that they can be coupled to the relative encapsulating tube, e) the mobile plates loaded with rod rows are transported automatically to the loading station for loading into the encapsulating tubes.

Description

40 45 503 817 The enclosure tubes can be brought into the charging position either manually or automatically. The pulley strings are loaded manually or by means of automatically operating means in the casing pipes. The automatically operating means are designed as fingers or vibrators and are arranged to load one or more of your enclosure tubes at a time with pulley strings.

The charging systems have in some cases been automated with the aid of pulley guides to bring the pulley strings in line with the center lines of the enclosure pipes. In some systems, there are arrangements for automatic weighing and measurement of the weights and lengths of the fuel cutters before charging. There are also arrangements for eliminating congestion and wedging during charging.

However, these systems entail a risk that the operator will make mistakes when assembling the cue players.

A system for assembling the coulter according to US 4,897,858 comprises a tray positioning station in close connection with a sorting path with a robot for transferring trays arranged between the sorting path and the tray positioning station. At the tray positioning station there are a number of carriages arranged, some with pallet storage trays and some with pile bearing washers. Pillows from a storage tray are sorted by type and length and placed on a pile bearing tray. The pellets on one and the same storage tray and bearing tray are all of the same type. The sorting path comprises an input, a work and an output station which are arranged one behind the other. The robot transfers the storage and storage trays, one at a time, to and from the positioning station and the input and output stations, respectively. An input device transfers pellets to the workstation from the storage tray in the input station. A gripper and measuring device measures a desired length of pellets in the workstation. Thereafter, the gripper and measuring device separate the measured length from any remaining cushions. An output device transfers the measured lengths from the workstation to a bearing washer at the output station. The dispenser then transfers any remaining pellets from the workstation back to the storage tray in the feed station.

The disadvantage of this system is that only one washer at a time can be filled with pulley strings. The system also includes a lot of tray handling.

The difficulties lie in effectively filling a casing tube with fuel pellets forming a pellet player with a certain composition and also being able to fill several pipes that have pellet players with different compositions. In addition, it is difficult to achieve control over which types of sockets are included and in what order these have been inserted into the enclosure tubes and what weight and length the socket player has. None of the described charging systems include a method for achieving this control. PRINCIPLE DESCRIPTION OF THE INVENTION, ADVANTAGES The invention relates to a method for loading nuclear fuel pellets into casing pipes and equipment for carrying out the method.

The method is based on a production process which comprises at least one charging station which comprises a pusher pusher and a pusher guide. The production process also comprises at least one cushion feeding station which comprises at least one cushion pusher and a length and a weight measuring means.

The stations are interconnected by at least one transport means. In close proximity to the stations, means for controlling and monitoring the production process are arranged. All equipment included in the production process is automatically working. At the charging station, enclosure tubes with different types of sockets in different zones are charged. The types of cuttings include cuttings of natural uranium and / or uranium of varying enrichment quantity. A pre-charged encapsulation tube thus comprises a cutters assembled from different types of cutters.

At the pellet feed station, fuel pellets are fed into the production process. The number of cushion feeding stations can be selected as needed, suitably one is selected for each cushion type. The fuel pellets are stored, until the time of feeding, one after another, forming pellet strings, in wave valleys on a pleated plate. An entire string of fuel pellets from a wave valley in the sheet corresponds to a certain string length.

The fuel pellets are transferred in the pellet feed stations by means of putty pusher to a mobile washer which consists of joined pipes between which guide gutters are formed. The washer is precision machined to allow an accurate alignment of the pulley strings in both the X and Y planes of the casing pipes to be charged. Several mobile washers can be in the transport means at the same time.

When charging casing pipes with, for example, an enriched zone, the same type of enriched fuel pellets can be charged in your feed stations or an input station can be loaded with fuel pellets of a different pellet type for preparation of charging of another rod type.

Each carriage feeding station comprises two types of feeding units, namely a full-string feeder and a partial-string feeder. These in turn comprise means for transferring the entire respective parts of the pulley strands from the plates to the trays. The full string feeder prepares trays with whole pulley strings for loading long zones where entire pulley strings fit within the remainder of the zone in question. The sub-string feeder in turn prepares trays with sub-strings for filling in zones and for zones with lengths that are shorter than the length of an entire pulley string.

The mobile badges are equipped with an escort rail on each short side.

The two escort memories, which contain information about the identity of the badge, 40 45 503 817 in turn have different identities. With the help of escort memory readers connected to an alarm device, a washer is prevented from turning 180 ° incorrectly during human intervention in the process. A first escort memory reader is arranged at the weight measuring means and a second escort memory reader at the charging station.

With information on the number of casing pipes to be loaded and its cuttings types and zone lengths, the number of washers with whole cuttings strings of each cuttings type can be calculated. The pellet feed stations can then work in parallel with applying fuel pellets to the calculated number of washers.

When the mobile tray is completed, the length measuring means is activated. The length of each individual pillow string is measured and recorded.

The tray is lowered onto the transport means and transported to the weight measuring means where the weight of the entire tray is measured and registered. The first escort memory reader reads the identity of the current badge, which is linked to the badge's own weight. The dead weight of the washer is subtracted from the measured weight and the actual pellet weight is distributed on the different pulley strands in relation to the previously measured pulley string lengths. This measured value is registered and used to calculate for each fuel rod the weight of each zone and the total weight of the assembled belt player.

The tray is transported to a queuing position.

Simultaneously with the work in the boiler accommodation stations, the casing pipes to be filled are brought into position in a charging pit arranged in close connection with the charging station. The positioning of the housing tubes is done with the aid of a step beam which, through continuous indexing, enables control of which housing tube is in each position. Since the center lines at the open ends of the casing tubes must be very carefully fixed in the same plane as the center axes of the casing strings on the washer, the casing tubes are moved against the casing guide.

When the enclosure pipes are in place, a washer with the desired enrichment is released from its position of purchase. With the help of the putty pusher, the putties are transferred to a fixed washer at the loading pit. The pellets are then moved by means of the same putty pusher over a break point to the pellet guide and, due to their own weight, they are dropped into the casing pipes. 'Mobile trays with whole pulley strings of current enrichment are taken to the charging station as long as the remaining zone length exceeds the length of an entire pulley string. When the entire pulley strands are measured in length, the remaining zone length is calculated on the basis of measured accumulated string lengths.

Based on this result, it can then be calculated how many pellets in each sub-pellet string are required to fill in the zone length in each encapsulation pipe. The sub-string feeder then prepares trays with sub-strings while the loading of the entire strands in the enclosure tubes continues. 40 45 so: 817 Transfer of pellets to mobile washers in the sub-string receiver takes place in one or fl your steps according to an iterative process. The partial string feeder can be controlled so that each individual pulley string on the mobile tray can have the desired length.

When the total length for one zone, or for the whole belt player, minus the accumulated zone lengths is less than: (1.5 times the nominal belt height, the next enrichment zone is started or the charging is terminated.

There is a continuous comparison between measured lengths and weights and theoretical according to the current rod construction plan. Finally, a check is made of the length of the remaining space in the enclosure pipe, residual length control. This length is also compared with the length according to the current rod construction plan. When faults, which cannot be rectified immediately, are detected, the relevant enclosure pipe (s) are discarded.

The method according to the invention can be carried out by means of manual operation of the included equipment or by means of automatic operation. In the embodiment described here, the method is suitably performed by means of a computer system which controls and monitors the charge of the pellets in the enclosure tubes and prepares reports on status and outcome.

The advantages of the method according to the invention consist in speed, flexibility and safety. The speed consists partly in the automatic registration of measured values and partly in the fact that parallel operations, with the application of pellets on trays and the loading of pellets in enclosure pipes, take place for each 'enrichment zone. The flexibility consists in that fuel pellets can be introduced into a number of cladding pipes at the same time and that it is possible to make each cladding pipe unique as different numbers of cutters can be included in a zone but where the zones in each cladding pipe have the same length. The system is easily expandable for handling several types of pillows. The method is thus flexible in terms of the number of zones, the number of fuel pellets, the number of enrichments and the number of enclosure pipes. The safety lies partly in the registration, which allows an exact control of what is loaded in each individual rod and partly in the comparison between measured values and values according to the rod construction plan. The final residual length control provides additional safety against air gaps and foreign materials, etc. between the pellets loaded in the housing pipes. The identification of tray identity provides security against enrichment faults and, through double escort memories, also manages to turn a tray 180 ° incorrectly.

DRAWING FIGURES The invention appears in more detail from the following description with the accompanying drawing figures. Figure 1 shows a schematic perspective view of the production process.

Figure 2 shows an example of the construction of a nuclear fuel rod with regard to the distribution of different types of cuttings. 40 45 503 817 Figure 3 shows a perspective view of a plate which is partially filled with fuel pellets.

Figure 4 shows a perspective view of a tray with escort inside which tray is arranged on a carrier. The washer is partially filled with fuel pellets.

Parts found in your figures are generally provided with the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION, DESIGN EXAMPLE _ The process is based on a production process, according to Figure 1, which includes equipment for carrying out the process. The production process comprises at least one charging station 1 which comprises a cushion pusher 2 and a cushion guide 3. The production process also comprises at least one cushion feed station 4 which comprises at least one cushion pusher 5 and a length and a weight measuring means 6, 7. The stations are interconnected by at least one transport means 8. In close proximity to stations 1, 4, means for controlling and monitoring the production process are arranged. A11 equipment included in the production process is operating automatically.

At the charging station 1, one or more of the enclosure tubes 9, which are provided with a bottom plug 10, according to Figure 2, are charged with fuel pellets 11 of different types in different zones. The types of cuttings include cuttings 11 of natural uranium and / or uranium of varying enrichment quantity. A pre-charged encapsulation tube 9 thus comprises a cutters assembled from different types of cutters.

The same assembly in different housing tubes 9 may comprise different numbers of fuel pellets 11 in corresponding zones, while the zone lengths, on the other hand, are the same.

At the pellet feed station 4, the fuel pellets 11 are fed into the production process. The fuel pellets 11 are stored until the time of feeding, in a magazine on corrugated rectangular plates 12, see also Figure 3, where the fuel pellets 11 are arranged one by one the pusher strings forming one after the other in the wave valleys 13. The plates 12 are insensitive and lack precision requirements . An entire pulley string from a wave valley 13 in the plate 12 corresponds to a certain string length.

The fuel pellets 11 are transferred, according to figure 1, in the pellet feed station 4 by means of the putty pusher 5 to a mobile washer 14, see also figure 4. The washer 14 consists of joined pipes 15 which together form a rectangular unit with guide gutters 16 formed between the pipes 15. 15 are, for example, circular-cylindrical or polygonal and are arranged on transverse struts 17.

The washer 14 is precision machined to allow accurate alignment of the pulley strands in both the X and Y planes of the enclosure tubes 9 to be loaded.

This means that the washer 14 has a well-defined distance between the guide gutters and that the respective center axes of the pipes 15 lie in one plane.

The production process also includes fixed trays of the same design as the mobile trays 14. The number of cushion feeding stations can be selected as required, suitably one is selected for each type of cushion. The embodiment described here comprises three cushion feeding stations, one for each enrichment one, enrichment two and natural uranium 4, 18, 19. The cushion feeding stations 4, 18, 19 can enter different types of cushion but only one type at a time.

The method allows the manufacture of one or more fuel rods 20, according to figure 2, with eg three different types of cuttings in six different zones. This means that a rod with, for example, natural uranium in a first zone 21, enrichment one in a second zone 22, enrichment two in a third zone 23, enrichment one in a fourth zone 24, enrichment two in a fifth zone 25 and natural uranium in a sixth zone 26 can be manufactured in a simple manner. At one and the same charging time, only fuel rods of the same rod type are charged.

After completion of charging, the housing tube 9 is provided with a top plug 27 and a finished fuel rod is obtained. Usually a spring 28 is arranged between the top plug 27 and the pad player to fix the pads 11.

When loading casing tubes 9 with, for example, an enriched zone, the same variant of enriched fuel pellets 11 can be charged in several pellet feed stations 4, 18, 19 or a pellet feed station, e.g. 18, can be loaded with fuel pellets 11 of another pellet type for preparation of loading of another pellet. rod type.

When charging the casing tubes 9, the assembled caster must be terminated at a specified point 29 in the top of the casing tube so that a certain empty space in it remains. The lengths of all zones are therefore calculated on the basis of a common point 30 in the bottom of the enclosure pipe. For verification of the empty space in the enclosure tube 9, the length of each individual pulley string is measured by the length measuring means 6 and the measured lengths are accumulated and compared with the zone lengths according to the current rod construction plan. After completion of filling, the remaining space is checked by measuring by means of a residual length measuring device 31, whereby a land signal is triggered if this space does not fall within certain tolerance limits.

In the embodiment described here, two of the pellet feed stations 4, 18 comprise two types of feed units, namely a full-strand feeder 32 and a partial-strand feeder 33. These in turn comprise means for transmitting whole respective parts of pellet strands on the mobile trays 14. The third pellet feed station 19, which is intended for feeding the natural uranium, is only equipped with a partial string feeder 33. Enrichment one and two normally have long zones where entire pellet strands are moved within the zones, while the natural uranium normally has zones that only hold parts of pellet strands.

The full-string feeder 32 thus prepares trays 14 with whole pulley strings for loading long zones where whole pulley strands fit within the remainder of the zone in question. The sub-string feeder 33 in turn prepares trays 14 with parts of pulley strings for filling in zones and for zones with natural uranium.

When inserting fuel pellets 11 into the full-string feeders 32 and the sub-string feeders 33, respectively, the plates 12 are placed in an elevator magazine 34. The elevator magazine 34 lifts one plate 12 at a time at an input position. A mobile tray 14 is moved to the input device (s) that are activated and lifted up at the input position. The mobile tray 14 is arranged on a carrier 35, see also figure 4, which in turn rests on the transport means 8.

The mobile tags 14 are provided with an escort memory 36 on each card side. Each escort memory 36 is arranged on the underside of the tray 14. The two escort memories 36, which contain information about the identity of the badge 14, in turn have different identities. A first escort memory reader 37 is provided at the weight measuring means 7 and a second escort memory reader 38 at the charging station 1. By means of the escort memory readers 37, 38 which are connected to an alarm means, a washer 14 is prevented from turning 180 ° incorrectly during human intervention in the process. Several mobile trays 14 can be located in the transport means 8 at the same time.

In the full-string feeder 32, the pulley strings are transferred in their entirety, by means of the pulley pusher 5, from the top plate 12 in the elevator magazine 34 to a fixed washer 39 at the accommodation position. The pulley pusher 5 is designed with fingers, one for each guide arm 16 which fingers are placed axially in line with the respective pulley string. The fingers are flexible so that if they encounter resistance when firing, the firing stops and triggers an alarm so that errors that have occurred can be corrected.

When the pulley strands are transferred to the fixed washer 39, the empty plate 12 is lifted to a position such that it can be shaved out on a collecting chute 40 by the pulley pusher 5 when it is moved backwards to its initial position. From the fixed washer 39, the pulley strands are transferred by means of the same pulley pusher 5 to the mobile washer 14 which is raised at the putty feed position. The transport means 8 continuously transports trays 14 to the respective feeding stations.

With information about the number of enclosure tubes 9 to be loaded and its cuttings types and zone lengths, the number of washers 14 with whole cuttings strands of each cuttings type can be calculated. The feed stations 4, 18, 19 can then work in parallel with applying fuel pellets 11 to the calculated number of washers 14.

When the mobile tray 14 is filled, the length measuring means 6 is activated.

The length measuring means 6 comprises for each pulley string a length measuring pin 41 which is connected via a connecting unit 42 to a weight 43. When the length measuring pin 41 is in its zero position, the length measuring pins 41 are locked by a common cross washer 44. When a measurement is to be made, the cross is 44 . The connecting unit 42 is released and advanced by means of the weight 43 until the length measuring pin 41 reaches the outermost pulley 11 in the respective pulley strands. The fuel pellets 11 are compressed so that any air gaps between the individual pellets 11 are eliminated. The weight 43 means that a definite calibrated measuring pressure on the cushion string is obtained. The length of the respective length measuring pins 41. measured and recorded. Thereafter, the cross washer 44 is reversed, which returns all the interconnection units 42 to the zero position. The washer 14 is lowered onto the conveying means 8 and passed on to the weight measuring means 7 at which it is lifted up at a weight measuring position 45. The weight of the whole washer 14 is measured by means of a standard precision scale 46. A device 47 is arranged on the precision scale 46. which allows the washer 14 to be lifted up from the carrier 35. The precision balance 46 with the device 47 is lifted by means of an axially movable cylinder 48.

The tag 14, according to Figure -1, is lifted down and transported further past the first escort memory reader 37. Measured values of weights and lengths are registered and linked to the identity of the tag 14. Thereafter, the mobile tag 14 is transported to a queue position 50.

The weight of the washer 14 is obtained by reading the escort memory 36 of the washer 14. The escort memory 36 contains information about the identity of the badge 14 which is linked to the dead weight 14 of the badge 14. The weight of the individual pulley strands is then calculated by subtracting the dead weight of the washer 14 from the measured weight and the actual pulley weight is distributed on the different pulley strands in relation to previously measured pulley string lengths. This measured value is registered and used to calculate for each fuel rod 20, according to Figure 2, the weight of each zone 21-26 and the total weight of the assembled belt pillar. At the same time as the work in the feeding stations 4, 18, 19, the encapsulation tubes 9 to be filled are brought into position in a charge rotation pit arranged in close connection with the charging station 1. The positioning takes place with the aid of a step beam equipment. The step beam equipment comprises a number of step beams 49 arranged one behind the other, in which the housing tubes 9 are arranged side by side.

The step beams 49 are linked together and index by a rotating movement continuously the current number of enclosure tubes 9 to the charging station 1. When entering enclosure tubes 9 in the step beam equipment, the identity of the enclosure tubes 9 is registered and connected to the obtained position in the step beam equipment. Since the center lines at the open ends of the casing tubes 9 must be very carefully fixed in the same plane as the center axes of the casing strings on a fixed washer 51, the casing pipes 9 are moved towards the casing guide 3 which is connected to the fixed washer 51.

The pulley guide 3 comprises an inlet guide for each casing tube 9, which is designed as a conical or funnel-shaped neck to facilitate the insertion of pulley strings. Also included is an output control for each casing tube 9, also the one designed as a conical or funnel-shaped neck which coaxially receives the casing tubes 9. The casing guide 3 ensures trouble-free charging of the fuel pellets 11 in the casing tubes 9. 40 45 m 503 817 When the casing tubes 9 are in place tray 14 with desired enrichment away from its queue position 50. At the charging station 1, the mobile tray 14 is lifted up at a charging position.

By means of the pulley pusher 2 in the charging station 1, the pulleys 11 are transferred to the fixed washer 51 at the charging pit. Then the pellets 11 are moved by means of the same putty pusher 2 over a break point to the pellet guide 3 and due to their own weight they are dropped into the casing tubes 9.

Mobile washers 14 with whole pulley strings of current aru-calibration are carried to the charging station 1 as long as the remaining zone length exceeds the length of an entire pulley string.

When the entire pulley strings are measured in length, the remaining zone length is calculated on the basis of measured accumulated string lengths. Based on this result, it can then be calculated how many pellets 11 in each sub-string are required to fill in the zone length. The sub-string feeder 33 then prepares washers 14 with sub-strings while the loading of the entire strands in the enclosure tubes 9 continues. Transfer of pellets 11 to mobile trays 14 in the partial string feeder 33 takes place in one or more steps according to an iterative process. The partial string feeder 33 can be controlled so that each individual pulley string can have the desired length. This is accomplished by transferring the pellets 11 on the top plate 12 of the hoist magazine 34 to a fixed washer 52 in the sub-string feeder 33. From this washer 52 a certain number of pellets 11 can be transferred to a short washer 53. The length of the strings is determined by by means of a position sensor 54. The position sensor 54 constitutes a stop towards which the pellets 11 are moved. The position sensor 54 is placed so that the number of pellets 11 that are to be included in the substrings at least at the same time is moved on.

The position sensor 54 is then moved forward so that the pulley strings which are to contain more pallets 11 can be supplemented. These iterative steps continue until all cushion strings have reached the correct length.

The pellets 11 remaining on the fixed washer 52 are then held in place by means of a press device 55 while the short washer 53 is lowered to a level at the height of the mobile washer 14 so that the pellets 11 in the substrands can be transferred to it. Only the fingers in the pulley pusher 5 that correspond to the pulley strings to be transferred are activated. When the total length for a zone, or for the entire belt player, the accumulated zone lengths are less than 10.5 times the nominal belt height, the next enrichment zone is started or the charging is terminated.

When the fuel pellets 11 have been loaded into the casing tubes 9, the mobile washer 14 is transported past an alarm means, for example in the form of photo or 56, for checking that the washer 14 is empty. If there are fuel pellets 11 left, an alarm is triggered, otherwise the empty mobile tray 14 is transported to a suitable position in the transport means 8. This position consists of either a waiting position 57 or a putty feeding position. 40 Û 3 8 1 '7 When the enclosure tubes 9 are fully charged, they are transported to a position for measuring the unfilled space remaining therein. The length of the unfilled space is measured by means of the said residual length measuring means 31 arranged to be slid into the coaxially placed enclosure tubes 9. This measuring device is designed so that when the relevant encapsulation tube 9 is moved towards a flexible stop, the stop is pushed backwards until a measuring pin is provided. centrally in the fl visible stop stops against the top pulley 11 in the housing tube 9. The length of the dipstick in this position is registered and compared with the values measured, accumulated and registered during the filling process. The measured length of the unfilled space is checked partly against internal encapsulation pipe length minus accumulated cuttings string lengths and partly against the remaining length according to the current rod construction plan.

The method according to the invention can be carried out by means of manual operation of the included equipment or by means of automatic operation. In the embodiment described here, the method is suitably performed by means of a computer system which controls and monitors the charge of the pellets 11 in the casing tubes 9.

A computer system suitable for the purpose can be divided into three hierarchical parts.

It includes a first computer for administration and documentation, a second computer for reporting status and production outcomes and a third computer for performing the direct process control as well as performing various checks and communication with the measuring devices and the escort memory readers.

Production documentation with rod construction plans is added to the first computer and from this information about enrichments and zones etc. included for the current rod type is passed on to the third computer. The second computer is provided with information about the respective identity and position of the enclosure tubes in the step beam equipment. The third computer communicates with the measuring means by receiving measured values and storing them, as well as performing certain calculations, such as accumulation of string lengths, calculation of sub-string lengths and weight per string length. When the enclosure tubes 9 are completed, information is sent to the second date which registers and stores production data about each individual enclosure tube 9. The second date then provides the first date with information which it converts into a basis for eg reporting to authorities, financial transactions etc.

The second computer can also be provided with information via a terminal 61 directly connected to it, whereby a semi-automatic control is obtained.

Claims (12)

19. 503 817 PATENT CLAIMS Method for charging at least one enclosure pipe (9) with fuel pellets (11) in a charging station (1), which fuel pellets are arranged in guide gutters (13) forming guide gutters (13), where length and weight measuring means (6, 7) are arranged to measure length and weight of each individual pulley string, and where pulley strands are loaded into the casing tubes by means of an automatically operating, individually maneuverable pulley pusher (2) via a pulley guide (3), characterized in that several washers (14) are completed, provided with pulley strings, in parallel and that the pellet strands, as they have been transferred to the washers, are loaded into the casing tubes assembling a pellet player with individual, correct zone lengths (21-25) according to the following steps: a) fuel pellets of different pellet types are fed into pellet feeding stations (4, 18, 19) , at least one pillow feeding station for each type of pillow, b) an empty mobile washer is automatically transported to the feeding station or feeding stations in which pillow strings are so-called a is transferred to mobile washers, c) all or parts of pulley strings with the correct individual length are applied to mobile washers, d) the individual length and weight of the transferred pulley strings are measured and length and weight measured values are recorded so that they can be connected to the enclosure pipe ( 9) in which the relevant fuel pellets are to be loaded, e) the mobile washer equipped with pellet strings is automatically transported to the charging station for charging the fuel pellets in the casing pipes. Method according to claim 1, characterized in that the length of the pulley strands applied to the mobile washers is measured with the length measuring means (6) which comprises a length measuring pin (41) connected to a weight (43), where the length measuring pin when measuring by means of the weight, it is moved towards the outermost pulley in the respective pulley string and where the length of the length measuring pin is measured and registered. 3. A method according to claim 1, characterized in that the correct length of parts of pellet strands is obtained by one or more steps in an iterative process which comprises a position sensor (54) which in each step is placed so that the number of pellets to be included at least in each sub-pulley string is transferred to the current mobile tag (14). A method according to patent 1 is loaded into the casing tubes (9) by being axially transferred from the relevant mobile washer (14) over a well-defined breaking point after which the pellet guide (3) is inclined so that the fuel pellets slide by their own weight and at a certain distance from each other into the sloping casing pipes (9) connected thereto and down into them for contact is obtained with the bottom of the casing pipes or a fuel jet in front. Method according to claim 1, characterized in that the empty mobile trays (14) are transported to a suitable position in the production process, for example an input position in one of the input stations (4, 18, 19) or a waiting position (57) in the transport means. (8). Equipment for charging at least one casing (9) with fuel pellets in a charging station (1), which fuel pellets are arranged in pellet strings in guide gutters, with pellet pusher (5) for fitting the required number of fuel pellets on washers (14), and with length respective weight net means (6, 7) arranged to measure the length and weight of each individual pulley string, characterized in that the equipment comprises a) mobile precision-made washers (14), b) at least one feeding station for each pellet type (4, 18, 19) c automatic operating means for recording the measured values measured by the length and weight measuring means, H 503 817 d) automatic operating means (8) for transporting the mobile washers (14) in and between the feeding stations (4, 18, 19) and the charging station ( 1). Equipment according to claim 6, characterized in that at least one input station (4, 18, 19) comprises two types of input units, namely a full-string feeder (32) and a sub-string feeder (33) which allow input of all or parts of pulley strings on the mobile washers (14). Equipment according to claims 6 and 7, characterized in that the sub-string feeder (33) comprises a position sensor (54) which, when preparing parts of pulley strings, assumes positions which allow transmission of the correct number of pulleys in each pulley sub-string. Equipment according to claim 6, characterized in that the mobile washers (14) are precision fabricated units comprising joined tubes (15) where guide grooves (16) are formed between the tubes, between which guide grooves the distance is well defined, and where the tubes (15 ) and center axes lie in one plane. Equipment according to claim 6, characterized in that the length measuring means (6) comprises a length measuring pin (41) connected to a weight (43). Equipment according to claim 6, characterized in that an escort memory (36) is arranged on each short side of the mobile badges (14). Equipment according to claim 6, characterized in that one or more control units for automatic control and monitoring and for reporting the status and outcome to one or more conventional process computers are arranged in close proximity to the stations (1, 4, 18, 19). and the transport means (8).