JPS61259195A - Multi-region charger for nuclear fuel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a nuclear fuel pellet loading device for loading nuclear fuel pellets 1- of a predetermined R into a fuel rod cladding tube.

[Technical backstory of the invention and its problems] - In general, fuel rods used in nuclear reactors are divided into a plurality of regions in the axial direction, and each region is loaded with a predetermined type of nuclear fuel pellet. There are many things that are. In particular, for fuel rods for BWR, nuclear fuel pellets with different U235" shrinkage degrees are used in each region for the purpose of flattening the axial distribution of in-reactor power, ensuring margin for reactor shutdown, and pursuing fuel economy. There is also one in which pellets with different concentrations of combustible absorbent are loaded in each area for the same purpose.

On the other hand, PWR fuel rods do not have the axial non-uniformity of the in-furnace cutting edge unlike BWR, but similar studies are being conducted to improve fuel economy. Roughly speaking, in an FBR, pellets are loaded in areas divided in the axial direction into a blanket section and a fuel section.

In addition to providing multiple regions within a single fuel rod as described above, the total length of the pellet row to be loaded is also determined.
For example, just looking at BWR, the length may vary depending on the type of nuclear reactor.

So, looking at this from the fuel processing process side, for example, B
Even when producing only fuel rods for WR, the total length of the pellet row to be loaded differs depending on the type of reactor, the axial area design differs depending on the type of fuel rod, and the type of pellets loaded in each area also differs. It turns out. Moreover, for fuel rods in which the overall length, area length, and type of pellet 1- vary depending on the type of fuel rod,
It is necessary to load Beren 1-, which has the same shape, without fail. Therefore, it takes a relatively long time to process each fuel.
Further, there are problems such as high cost.

FIG. 7 is a vertical side view of a typical nuclear fuel rod, in which a predetermined number of pellets 1-2 such as uranium dioxide UO2 are loaded into a zirconium alloy or stainless steel cladding tube 1, and the pellets are inserted from one end into a spring 3. The pellet 2 is pressed by the cladding tube 1, and end plugs 4 and 5 are welded to both ends of the cladding tube 1.

As shown in FIG. 8, two regions are formed in the cladding tube 1 of the nuclear fuel rod, a region A where pellets 2 are loaded and a blemish region B where no pellets are loaded. Blenheim portion B is set to a predetermined length in order to sufficiently store the generated fissile gas, and the length of area taA into which pellets 2 are loaded is also determined accordingly. on the other hand,
The length of one pellet varies within a certain tolerance. Furthermore, when the pellet loading area is divided into a plurality of areas depending on the type of pellet, the length of each area is generally defined as follows.

That is, if the area is divided into, for example, five areas as shown in FIG. 9, the length n i of area A1, AI
Length u2 including territory area A2 area, length 13 including area A2 and area A3, A1 area, A2 area,
The method of defining the length fJ4, which is the sum of the A3 area and the A4 area, and the length L2 of the Blenheim part B, and the quality of each area from the A1 area to the A4 area, as shown in FIG. There is a method in which only the final area A5 is defined by the total length from area A1 to area A5, that is, the length Ll of area A loaded with pellets. Then, the respective tolerances such as the length of each area A1 to A4 and the length of area A are set to be slightly longer than the length of one pellet, and depending on whether one pellet is added to the row or not. This allows the length to be kept within tolerance.

By the way, when loading pellets into fuel rods with a multi-area design, conventionally, multiple types of fuel pellets 2a, 2b are used as shown in FIG.

2c and 2d are arranged and placed on the conveying tray 6 for each type, and the respective conveying trays 6 are placed on the loading table 7 in a line corresponding to the order of loading. On the other hand, on one side of the loading table 7, there are a plurality of dividers a1,
a2. - Arranging an alignment v-tray 8 provided with...
Sequentially arrange the types of pellets to be loaded into each area■
The pellets are arranged on a tray 8, then each divider is removed, and the rows of pellets are pushed and loaded into the cladding tube 1 using a pellet pusher.

However, when loading pellets into cladding tubes manually as described above, it is necessary to place similarly shaped pellets and pellet trays in place without fail, and to place each type of pellet in a lengthwise manner in each area. Check the types of pellets! Since it is necessary to arrange the items in a row, the work is inefficient and takes a long time. Further, if an attempt is made to increase only the loading speed, there is a problem that it is difficult to reliably prevent loading errors from occurring.

[Purpose of the invention]

In view of these points, the present invention automatically forms rows of fuel pellets to be loaded into each area within the fuel rod cladding tube from a pellet conveying tray, and prevents mixing of different types of nuclear fuel pellets. It is an object of the present invention to provide a nuclear fuel multi-area loading device that can reliably automatically load predetermined nuclear fuel pellets into predetermined areas.

(Summary of the Invention) The present invention provides a nuclear fuel multi-area loading device for loading multiple types of nuclear fuel pellets into each area of a predetermined length into a cladding tube, in which each nuclear fuel pellet loaded into each area is The nuclear fuel pellets are placed in an array, and the pellets are placed in front of the pellet conveying trays, which have the same number as the area, and which are movable in a direction perpendicular to the column direction of the pellets. An alignment V-tray fixedly installed so as to be on the same axis as the vertical rows, and fuel rod cladding tubes are sequentially moved and fixed adjacent to the tip of each of the above-mentioned alignments A cladding tube fixing device capable of forming a pellet row of the predetermined length is formed from the pellet rows transferred to each alignment v tray, and is arranged along each of the above-mentioned alignment v trays, and a pellet row of the predetermined length is formed. It is characterized by having a pellet row length forming mechanism for inserting the pellets into the mud cladding tube, and forming a row of nuclear fuel pellets to be loaded into each area in each alignment tray, and forming a row of nuclear fuel pellets to be loaded into each area of the tray. By sequentially inserting rows of pellets into the cladding tube, a plurality of types of nuclear fuel pellets can be automatically inserted into the cladding tube.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a plan view showing a schematic configuration of a nuclear fuel multi-area loading device according to the present invention, in which the nuclear fuel pellet area of a fuel rod is made up of four areas.

In the figure, numerals 10a, 10b, 10c, and 10d indicate different types of nuclear fuel pellets 11a, respectively.

Each of the trays 10a, 10b, and 10c is a tray for transporting pellets in which a plurality of rows of pellets 11b, 11c, and 11d are arranged and stacked.

10d are each placed on a tray support plate 12 (FIG. 2) that is movable in a direction perpendicular to the column of pellets.

In front of each tray support plate 12, pellet conveying trays 10a, 10b, 10c are placed on the tray support plate 12 according to the movement of the tray support plate 12.
, 10d of nuclear fuel pellets are aligned such that their axes coincide with the vertical rows of nuclear fuel pellets 13. One tray 13 is fixedly installed on each of the trays 13, and furthermore, at the front of each aligned A cladding fixing device 15 is provided on the axis to which a fuel rod cladding 14 can be attached.

On the other hand, above the - side of each of the tray support plates 12, the nuclear fuel pellets h11a, 11b, 11c, and 11d are moved in a direction parallel to the vertical rows, and the nuclear fuel pellets arranged on the pellet conveying tray are moved in the vertical direction. A pusher device 16 is provided for pressing the nuclear fuel pellets onto each aligned V-tray 13, and transfers the row of nuclear fuel pellets onto each aligned V-tray 13.
On one side, there is a pellet row length forming mechanism 17 that cuts out and forms pellet rows of a predetermined length from the pellet rows transferred to each of the arrays V1 to Ray, and inserts the pellets of the predetermined length into the cladding tube. is installed.

By the way, as shown in FIG. 2, the butcher device 16 is fixed to the tip of an L-shaped operating rod 19 pivoted at a point 18, and is connected to the column of pellets on the pellet conveying tray 10a. It has a frame 20 extending in a parallel direction, pulleys 21 are attached to both front and rear ends of the frame 2o, and a belt 22 is wound around both pulleys 21. The belt 22 has a button rod 2 that protrudes downward.
The top end of 3 is attached C, and the button rod 23 is
The pellets are slidably engaged with a guide rod 24 mounted on the frame body 20 in parallel with the column of pellets, and can be moved in the front-rear direction along the guide rod 24 by movement of the belt 22.

Further, the pulley 21 is configured such that one of the pulleys is driven by a drive motor 25 mounted on the frame 20, and an interlocking shaft portion between the drive motor 25 and the pulley 21 has a structure shown in FIG. As shown in FIG. 2, a slip clutch 26 is provided which releases its interlock when a predetermined load or more is applied to the pulley 21.
An air cylinder 27 for swinging the operating rod 19 around the point 18 is connected to the other end of the air cylinder 9 . However,
By the operation of the air cylinder 27, the button rod 23 moves from the position where its tip engages with the end of the nuclear fuel pellet array (Fig. 3) to the upper position @ (the upper position where the engagement with the nuclear fuel pellet array is released). Figure 4) can be taken.

The pellet row length forming mechanism 17 has a machine frame 28 arranged along the alignment V-tray 13, and a belt 30 is wound around pulleys 29 provided at both front and rear ends of the machine frame 28. The machine frame 28 is movable up and down in a plane parallel to one inclined surface of the alignment V tray 13 by an air cylinder 31 and a guide rod 32, and the belt 30 is attached to the alignment V tray 13. A length forming mold 33 that can be inserted into the groove of the V-tray is installed and protrudes along one of the inclined surfaces. Further, a stopper 34 is disposed near the end of the alignment V-tray 13 and is movable in the axial direction of the alignment V-tray 13 and can be inserted into and removed from the groove of the alignment V-tray 13.

Therefore, in order to form a line of a predetermined length of nuclear fuel pellets l- in the above-mentioned apparatus, the following procedure is performed. That is, the operating rod 19 is swung by the air cylinder 27, and the pusher rod 23 is lowered so that it touches the rear end of the leftmost pellet row in the figure above the pellet conveying tray 10a, as shown in FIGS. 2 and 3. position and then actuating the drive motor 25 to advance the pusher rod '23 through the belt 22, which pushes and transfers the pellet row onto the aligned V-tray 13.

When one row of pellets is pushed out in this way, the button rod 23 is returned to its original position, and the pellet conveying tray 10a is moved one pitch to the left in the figure via the tray support plate 12, and then as described above. In the same manner as above, the second row of pellets is pushed out onto the aligned V-tray 13.

By repeating this, the pellets are pushed out until the leading end of the pellet row contacts the stopper 34, that is, until the slip clutch 26 idles. When the tips of the pellet row come into contact with the stopper 34 in this way, the pellets are aligned in the row and are held between the butcher rod 23 on the V-tray support plate (Fig. 5 (a), Fig. 6 (
a)).

At this time, since the length of the pellets varies, the end position of the pellet can be at any position within the tolerance range of the row length. However, if the tolerance range is longer than the length of the pellet, there will be at least one end position within this tolerance range.

On the other hand, the row length forming mold 33 has a stopper 34 at its tip end.
The column length forming mechanism The machine frame 28 of No. 17 is lowered, and the row length forming mold 33 is lowered diagonally from above along the side walls of the arraying trays 1 to 13, and the pellets on the arraying trays 13 are removed from the pellets on the trays 13 as shown in FIG.
b) and push it upward diagonally to the right as shown in FIG. 6(b).

Next, the row length forming mold 33 is moved along the aligned V h lay 13 via the pulley 29 and the belt 30.
As shown in FIG. 5(C), the row length is moved in four directions and is brought into contact with the end surface of the pellet that is in contact with the pellet being pushed up by the row length forming mold 33, and whose length is within a predetermined tolerance. The pellet row with the pellets is held between the stopper 34. Therefore, the stopper 34 is moved upward from the groove of the alignment V-tray 13 to release the gripping state of the pellet row, and then the row length forming mold 33 is further moved in the direction of the stopper 34, and the tip of the alignment V-tray 13 is moved upward. The rows of nuclear fuel pellets cut into the predetermined length are pushed out and inserted into the fuel rod cladding tube 14 coaxially disposed on the side.

Note that when the pellets pushed diagonally upward by the row length forming mold 33 on the alignment V tray 13 move in the pellet extrusion direction of the row length forming mold 33, the pellets move along with the row length forming mold 33. In order to prevent the pellets from moving, for example, by changing the left and right angles of the grooves of the alignment v-tray 13, as shown in Fig. It may be made larger than that.

Therefore, in the present invention, the nuclear fuel pellets are transferred from the pellet transport tray loaded with the first nuclear fuel pellets onto the alignment v-tray 13, and the first fuel pellet row of a predetermined length is formed as described above. and inserted into the cladding tube 14 as fuel in the first region. The cladding tube 14 into which the fuel of the first region has been inserted in this way is then moved to the adjacent cladding tube fixing device for the insertion of the second nuclear fuel pellets and fixed there, and there, in exactly the same manner as described above. A train of nuclear fuel pellets of a predetermined length is inserted into the cladding tube. Further, the same procedure is repeated for the third nuclear fuel cell 1-. In this way, the pellets on each pellet conveying tray can be sequentially loaded into the region on the end plug side of the cladding tube.

By the way, when inserting nuclear fuel pellets into the final region, the shape of the stopper 34 is made to be different from other stoppers because it is necessary to control the total length of the nuclear fuel pellets inserted into the cladding tube. That is, as shown in FIG. 1, the stopper 34 has a small diameter portion that can be inserted into the cladding tube in the axial direction, and its tip is brought into contact with the end surface of the pellet row completely inserted into the cladding tube. , the row length forming claw 33 is inserted into the alignment V1-ray 13 at a position a predetermined length from the rear end of the stopper 34.

In this case as well, the nuclear fuel pellet array in the final region can be made to a predetermined length in exactly the same manner as described above, and after removing the stopper 34, the nuclear fuel pellets 1 formed to a length on the aligned V-tray 13 are - Insert the row into the cladding tube. In this way, it is possible to form and load a pellet array whose length falls within tolerances over the entire area of the nuclear fuel pellet array within the cladding tube.

Moreover, as shown in FIG. 1, the above-mentioned loading operation is carried out on each of the pellet conveying trays 10a, 10b, and 10c.

Transfer from 10d to each alignment tray 13 and insertion into the cladding tube can be performed in parallel.

〔Effect of the invention〕

Since the present invention is configured as described above, the nuclear fuel pellets to be loaded into each region of the fuel rod are transferred into the corresponding alignment tray, where they are each formed into a predetermined row length,
The pellet rows formed to the predetermined row length can be automatically inserted and loaded into the cladding tube in order, and the conventional manual work can be significantly reduced, and work efficiency can be greatly improved.

Moreover, it is possible to completely prevent the mixing of different types of pellets in each region, and the length of the pellet row in each region can be reliably kept within tolerances by the pellet row length forming mechanism, ensuring quality as a fuel rod. can also be reliably maintained. Furthermore, each area can be loaded in parallel, and the time required for loading multiple areas can be significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a plan view schematically showing the nuclear fuel multi-area loading device of the present invention, and Fig. 2 is a plan view showing the arrangement of nuclear fuel pellets in the present invention. A schematic perspective view, FIGS. 3 and 4 are operation explanatory diagrams of the button shear device, and FIGS. 5(a) and (b)
), (c). (d), and FIGS. 6(a), (b), (C)'. (d) is an explanatory diagram of the row quality formation operation in the device of the present invention, FIG. 7 is a longitudinal cross-sectional side view of a general fuel rod, FIG. 8 is an explanatory diagram of the relationship between the fuel region and the blemish part, and FIG. 10 is an explanatory diagram of a method for defining the length of each fuel region when each fuel region is composed of a plurality of regions, and FIG. 11 is an explanatory diagram of a conventional loading method. 10a, 10b, 10c, 10d--Pe L/foot feeding tray, 13...Aligned V-tray Ni 14 river cladding tube, 15
...Fixing device in cladding tube, 23...butsusha rod, 33
... Length forming claw, 34... Stopper. Applicant's agent Kiyoma Inomata 1st eye 3rd eye 4th figure 5 (a) (b) (c) (d)
Figure 6 (a) (b) (c) (d
) Figure 2 also has 8 eyes, 9 eyes, 10 eyes, and 11 figures.

Claims (1)

[Scope of Claims] 1. A nuclear fuel multi-area loading device for loading multiple types of nuclear fuel pellets into each area of a predetermined length into a cladding tube, in which each nuclear fuel pellet is loaded into each area. The nuclear fuel pellets are placed in an array, and the pellet conveyance trays have the same number as the area, and are movable in a direction perpendicular to the column direction of the pellets, and the vertical column of the pellets is arranged in front of each pellet conveyance tray. an aligned V-tray fixedly installed so as to be on the same axis as the aligned V-tray, and a cladding tube in which fuel rod cladding tubes can be successively moved and fixed on the same axis as the aligned V-tray adjacent to the tip of each of the aligned V-trays. a fixing device disposed along each of the aligned V-trays, forming pellet rows of the predetermined length from the pellet rows transferred to each of the aligned V-trays, and covering the pellets of the predetermined length of the rows with the above-mentioned coating; 1. A nuclear fuel multi-area loading device, comprising: a pellet row length forming mechanism inserted into a tube. 2. Alignment V for loading nuclear fuel pellets in the final area
The nuclear fuel multi-area loading device according to claim 1, wherein in the tray, a pellet array is formed whose length corresponds to the difference between the entire length over the entire area and the pellet array already loaded. .