JP3088954B2 - Reactor fuel pellet sorting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for sifting debris, powder, and the like mixed in fuel pellets during the transportation of fuel pellets produced in a reactor fuel pellet production line to the next step. The present invention relates to a fuel pellet sorting apparatus which sorts only non-defective pellets and supplies them to the next step.

[0002]

2. Description of the Related Art As is well known, the above-mentioned fuel pellets are manufactured into a specified size through a press-forming, sintering and grinding process of a powder of uranium oxide or the like, and the manufactured fuel pellets are formed on a fuel rod. After being loaded into the cladding tube, it is assembled into a fuel assembly. By the way, the fuel pellets produced through the above manufacturing process include pellet fragments broken during sintering,
Alternatively, if the grinding powder generated during the grinding is mixed and adhered, and the fuel pellets are transported to the subsequent process as they are, the mixed pellet fragments and powder may be contaminated as foreign matter.
It interferes with the inspection of the fuel pellets and the work of loading the cladding tubes, which are carried out in the subsequent process.

[0003] In this regard, a sorting apparatus that automatically removes fine fragments and the like from fuel pellets continuously conveyed through a manufacturing process and sends only good pellets to the next process has not been put into practical use. At present, good pellets are manually selected in many cases. Therefore, the inventors made a prototype of a fuel pellet sorter as shown in FIG. 3 by applying an electromagnetic vibration type linear feeder known as a parts feeder, installed it on a fuel pellet production line, and conducted an actual machine test. Tried. That is,
3 (a) and 3 (b), reference numeral 1 denotes a pellet sorter, 2
Is a transport line for supplying the fuel pellets 3 produced in the production line to the pellet sorting apparatus 1, and 4 is a parts feeder for transporting non-defective pellets sorted by the apparatus 1 to a subsequent process. And a trough 1b accommodating the transfer tray 1a, an electromagnetic vibration type feeder driving unit 1c that mounts the trough 1b and applies an exciting force in the transfer direction, and At the discharge end side of the trough 1b, a suction nozzle 1d for discharging fragments of the pellets and powder is opened at the bottom surface. The transport tray 1a has a number of transport rails, and the gap between the transport rails is set to be slightly smaller than the outer dimension (diameter of the pellet) of the fuel pellet 3.

In this configuration, when the fuel pellets 3 containing the debris and the powder are supplied to the transport tray 1a of the linear feeder 1 via the transport line 2, the pellets 1 are vibrated by the excitation force from the drive unit 1c. While moving forward along the transport rail of the tray 1a, fine fragments, powders, and the like (hereinafter, referred to as crushed pieces 3b) are shaken off from the rail gap of the tray-shaped tray 1a in the moving process, and the non-defective pellets 3a having a predetermined size are obtained. Only the material moves to the end of the tray 1a and falls into the subsequent parts feeder 4, where it is arranged in a line and conveyed to the subsequent process.

[0005] On the other hand, in the course of transportation by the straight-ahead feeder 1, fine fragments 3b, such as fine fragments and powder, that have slid through the rail gap of the tray-like tray 1a fall to the bottom surface of the trough 1b, and then are vibrated by the drive unit 1c. It travels forward on the bottom wall surface and is collected by a debris collection device (not shown) through the suction nozzle 1d.

[0006]

By the way, when the above-described fuel pellet sorting apparatus was actually assembled into a fuel pellet production line and an actual machine test was conducted, it was found that there were the following problems. That is, the fuel pellets 3 sent from the manufacturing process also contain relatively large-sized debris having a sharp outer portion with a missing portion. In addition, such a crushed piece often has a phenomenon in which a pointed portion in the rail gap of the tray-shaped transport tray 1a is sandwiched in a wedge shape in the middle of the transfer path and bridged to that portion and stopped. When such a bridge of debris occurs,
This becomes an obstacle, and the progress of non-defective pellets sent from behind is hindered, which leads to a trouble that the transport function of the straight-ahead feeder 1 does not work properly. In addition, in order to remove the debris caught in the rail gap of the transport tray 1a, it is necessary to stop the operation each time, and it is difficult to actually remove the debris. Turned out to be insufficient.

[0007] Therefore, an object of the present invention is to solve the above-mentioned problems, and fine shards and powder mixed in the fuel pellets supplied through the manufacturing process are smoothly sieved and separated and collected, and only the non-defective pellets are recovered. An object of the present invention is to provide a highly practical apparatus for sorting fuel pellets for a nuclear reactor, which is improved to be sent to a process.

[0008]

In order to achieve the above object, a fuel pellet sorting apparatus according to the present invention is constructed as follows. 1) In the first invention, an endless wire mesh belt conveyor having a pellet transport surface formed of a wire mesh for sieving, a vibration knocker for hammering the transport surface of the conveyor, and a wire mesh belt conveyor are accommodated. In addition, a pellet sorting device is configured by combining a trough having an opening on the bottom surface with a debris discharge port, and the pellets supplied on the wire mesh belt conveyor are sieved into non-defective pellets, debris and powder during the belt transport process, and the debris is separated. The powder is dropped into the trough and collected from the discharge port, and the good pellets are sent out from the end of the wire mesh belt conveyor to the subsequent stage.

Further, a rib-shaped scraper is provided dispersed on the periphery of the wire mesh belt conveyor, and scraps and powder of pellets dropped on the bottom surface of the trough by the orbital movement of the scraper are raked and collected to an outlet. And 2) In the second invention, a flexible wire mesh belt in which the conveying surface of the pellets is constituted by a wire mesh for sieving, the pellet supply side end is fixed, and the other end is a free end, is laid horizontally. Combining a wave generating mechanism for applying a wave motion to the wire mesh belt from the upstream side to the downstream side of the pellet conveyance, and a trough containing the wire mesh belt and the wave generating mechanism and having a debris discharge port opened at the bottom surface. A pellet sorter is constructed to transport the pellets supplied on the wire mesh belt forward by the wave motion of the belt while sieving the non-defective pellets, debris and powder in the transport process. Drop it and collect it from the outlet, and send good-quality pellets to the subsequent stage from the end of the wire mesh belt.

[0010] In the above structure, the wave generating mechanism is provided on the lower surface of the chain along the wire mesh belt, and the rib is dispersed on the chain periphery of the mechanism and slides on the back surface of the wire mesh belt. In addition to the above-mentioned configuration, the above-mentioned wave applying plate is used as a scraper, and the fragments and powder of the pellets dropped on the bottom surface of the trough by the orbital movement are scraped to the discharge port to be collected.

Further, in the configurations 1) and 2), there is a configuration in which a soft pad is provided at the tip of the scraper. In the configuration of the above 1), the fuel pellets mixed with debris supplied to the wire mesh belt conveyor are sieved by the vibrating force of the knocker hitting the belt surface in the process of conveying the conveyor, and the sieving is promoted. The wire passes through the wire mesh and falls to the bottom wall of the trough, and only the good pellets are transported to the end of the conveyor and sent out to the next step via a chute or the like. In this case, the debris of the sharp-pointed pellet behaves like a dance on the wire mesh belt due to the hammering of the knocker and the spring effect of the belt itself, so that there is no danger that the debris will bite into the mesh of the belt.

Further, in the configuration of the above item 2), the wave imparting plate of the wave generating mechanism moves while sliding on the back surface of the wire mesh belt. As a result, a undulation is formed on the belt surface of the wire mesh belt, where a portion pushed up by the wave applying plate becomes a peak, and a slack portion between the wave applying plate and the next wave applying plate becomes a valley. A wave motion that moves from the upstream pellet supply end side to the downstream pellet delivery end side at a speed corresponding to the orbital motion is generated.

Thus, the fuel pellets mixed with debris supplied to the wire mesh belt conveyor are conveyed forward while rolling on the belt surface by the above-mentioned wave motion of the wire mesh belt. After passing through the mesh of the wire mesh belt and falling to the bottom wall of the trough, only good pellets are transported while rolling on the wire mesh belt,
It is sent from the end of the conveyor to the next process via a chute and the like. In addition, there is no risk that crushed pieces of the pellet having a sharp tip will bite into the mesh of the wire mesh belt.

The crushed fine particles and powder sieved to the bottom surface of the trough as described above are fed to an endless wire mesh belt conveyor or a scraper orbiting with a chain of a wave generating mechanism to slide on the bottom wall surface of the trough. In the return process, the debris is raked into the debris discharge port and collected. Here, by providing a soft pad at the tip of the scraper so as to slide on the bottom wall surface of the trough, fine powder can be satisfactorily discharged without leaving any fine powder.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments corresponding to the first and second inventions will be described with reference to the drawings.
In the drawings of each embodiment, the same members corresponding to those in FIG. 3 are denoted by the same reference numerals. [Embodiment 1] FIGS. 1A to 1C show a first embodiment of the present invention.
FIG. 2 is a configuration diagram of an embodiment corresponding to FIGS.
Reference numeral 5 denotes a wire mesh belt conveyor of a pellet sorting device installed on a transport path between the upstream pellet transport line 2 and the downstream parts feeder 4, and the conveyor 5 is a trough 6
It is laid and housed inside. Here, the wire mesh belt conveyor 5 is composed of an endless wire mesh belt 5c stretched between the driving pulley 5a and the driven pulley 5b, and stands up at a constant pitch on the circumference of the wire mesh belt 5c. A line of scrapers 5d is provided. A soft pad 5f made of silicon rubber or the like is attached to the tip of the scraper 5d as shown in FIG. 5 (c). Further, the wire mesh belt 5c is knitted one size smaller than the outer size of the specified fuel pellet. Reference numeral 5e denotes a conveyor drive motor. Further, the wire mesh belt 5c is provided with a knocker 7 for vibration on the back side of the transport surface. This knocker 7
Plays a role of hammering the belt surface to promote a sieving operation described later, and operates to tap the belt surface lightly at a period of about 0.2 to 0.5 seconds.

On the other hand, the trough 6 and the wire mesh belt conveyor 5
Is assembled so that the tip of the scraper 5d attached to the conveyor slides against the bottom wall of the trough, and the trough 6 is directed toward the parts feeder 4 on the discharge end side of the conveyor 5. A debris discharge port 6b is opened on the opposite bottom wall.
With such a configuration, with the wire mesh belt conveyor 5 of the pellet sorting device driven and driven in the direction of the arrow shown in the figure and the knocker 7 hammering, the fuel pellets 3 mixed with crushed pieces that have undergone the forming, sintering, and grinding manufacturing processes. Is continuously supplied to the wire mesh belt conveyor 5 through the transport line 2, the fuel pellets 3 are transported on the upper surface of the belt, and fine fragments 3b such as debris and powder mixed in the fuel pellets 3 during the transport. Is sieved from the middle through the mesh of the wire mesh belt 5c, falls on the bottom of the trough 6, only the non-defective pellets 3a are conveyed to the end of the conveyor 5, and supplied to the subsequent parts feeder 4 via the chute 6a. , And are transferred to the next step.

Moreover, in the above-mentioned conveying and sieving process,
Since the pellets 3 behave on the belt surface due to hammering by the knocker 7 and the spring effect of the wire mesh belt, the sieving is performed such that the sharpened pellet fragments bite into the wire mesh in a wedge shape. Almost no trouble occurs. Also, even in the event that debris gets into the mesh of the belt during the transport process, due to the tension difference between the upper side (tension side) and the lower side (slack side) of the wire mesh belt, the wire mesh belt is returned on the return side of the lower surface of the conveyor. The pieces of the mesh 5c are slightly loosened and bite into the mesh, fall off the belt, and fall to the bottom of the trough 6. This does not hinder the conveyor's transport function and sieving function.

The debris 3b that has fallen to the bottom of the trough 6
Is scraped to the debris discharge port 6b by the return operation of the scraper 5d orbiting on the lower surface side of the conveyor 5 together with the wire mesh belt 5d, and is sucked and collected by the debris collection device (not shown) through the discharge port. In this case, by covering the tip of the scraper 5d with the soft pad 5f, it is possible to sweep the fine powder without leaving any fine powder.

[Embodiment 2] FIG. 2 shows an embodiment corresponding to the third and fourth aspects of the present invention. In this embodiment, instead of the wire mesh belt conveyor of the first embodiment, fuel pellets 3 are used. A flexible belt-shaped wire mesh belt 8 along a transport path, and a wave generating mechanism 9 disposed on the lower surface side of the wire mesh belt 8
Is laid.

Here, the wire mesh belt 8 is supported on the wave generating mechanism 8 with its pellet supply end side fixed to the wall surface of the trough 6 via a fixture 10 and its sending end side free end. Further, the wave generating mechanism 9 has a rib-like shape on the circumference of the chain 9c with respect to a chain mechanism including an endless chain 9c and a driving motor 9d which are stretched between a driving sprocket 9a and a driven sprocket 9b arranged in front and rear. The wave imparting plates 9e are dispersedly connected. Other structures are the same as in the first embodiment.

In this configuration, when the chain 9c of the wave generation mechanism 9 is driven to rotate in the direction indicated by the arrow in the drawing, the tip of the wave applying plate 9e moves while sliding on the back surface of the wire mesh belt 8 with this circular movement. As a result, a wave motion is generated on the belt surface of the wire mesh belt 8 such that the undulation moves from the upstream side to the downstream side. Here, when the fuel pellets 3 are supplied to the wire mesh belt 8 from the transport line 2, the pellets 3 are sent to the delivery end while rolling on the belt surface on the undulation of the above-mentioned wave motion, and are transported. Debris 3 such as debris and powder mixed in the pellet 3 on the way
The wire b passes through the mesh of the wire mesh belt 8 and is sieved so as to fall on the bottom wall of the trough 6, and only the good pellets 3a are sent from the end of the wire mesh belt 7 to the subsequent parts feeder 4 via the chute 6a. Further, the crushed pieces 3b that have been sieved and fallen to the bottom of the trough 6 return to the wave applying plate 9e orbiting together with the chain 9c of the wave generating mechanism 9 as a scraper in the return stroke (the wave applying plate 9e in the return stroke).
(It is set so that the tip of the blade slides on the bottom surface of the trough 6.) The scrap is scraped to the debris discharge port 6b, and is sucked and collected by the debris collection device (not shown) through the discharge port. In addition, in order to scrape without leaving fine flakes, the wave imparting plate 9e
Can be covered with a soft pad as described in the first embodiment.

Further, as can be seen from the above description, since the pellets 3 are conveyed while rolling on the wire mesh belt 8, there is no risk of troubles such as the sharp debris 3b getting into the mesh of the belt and stopping. Further, since the wire mesh belt 8 is composed of a single wire mesh, the crushed pieces 3 b that have passed through the mesh fall directly to the bottom wall of the trough 6. Therefore, like the wire mesh belt conveyor employed in Example 1, the debris 3b that has passed through the mesh of the wire mesh belt is caught in the mesh of the return-side belt and bites into the drive roller,
As a result, there is no risk of malfunction such as causing an abnormality in the drive system of the conveyor.

[0023]

As described above, according to the structure of the present invention, there is no trouble such that the fragments and the fuel pellets mixed with the powder continuously conveyed through the manufacturing process enter the wire mesh belt. Can be separated into fine pieces and powder in the transportation process, and only good pellets can be sent to the next step, thereby providing a highly functional and reliable fuel pellet sorting apparatus. .

[0024] In particular, a vibration knocker is provided on the wire mesh belt conveyor to hammer the belt surface (claim 1), or a wave motion is imparted to the wire mesh belt by a wave generating mechanism (claim 3). The sieving function is improved. Further, a scraper is attached on the circumference of the wire mesh belt conveyor (Claim 2), or the wave imparting plate of the wave generating mechanism is a scraper (Claim 4), and the movement of the scraper is used by utilizing the movement of the return stroke. The debris and powder that have fallen to the bottom surface can be collected by scraping them to the debris discharge port. Furthermore, by providing a soft pad at the tip of the scraper (claim 5) and sliding the soft pad on the bottom surface of the trough, there is an advantage that fine powder can be swept and collected without remaining.

[Brief description of the drawings]

FIGS. 1A and 1B are configuration diagrams of a pellet sorting apparatus corresponding to Embodiment 1 of the present invention, wherein FIG. 1A is a configuration diagram of the entire apparatus, FIG. 1B is a cross-sectional view taken along the line AA in FIG. ) Is an enlarged sectional view of the scraper

FIG. 2 is a configuration diagram of a pellet sorting apparatus according to a second embodiment of the present invention.

FIGS. 3A and 3B show a conventional pellet sorting apparatus, wherein FIG. 3A is a configuration diagram of the entire apparatus, and FIG. 3B is a cross-sectional view taken along the line BB in FIG.

[Explanation of symbols]

 Reference Signs List 3 fuel pellet 3a good pellet 3b crushed piece 5 wire mesh belt conveyor 5c wire mesh belt 5d scraper 5f soft pad 6 trough 6a chute 6b debris discharge port 7 vibrating knocker 8 wire mesh belt 9 wave generating mechanism 9c chain 9e wave belt plate 10 Fixture

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiko Inui 4-33, Muramatsu, Tokai-mura, Naka-gun, Ibaraki Prefecture Inside the Tokai Works, Power Reactor and Nuclear Fuel Development Corporation (72) Inventor Takao Kawasaki 4-, Muramatsu, Tokai-mura, Naka-gun, Ibaraki 33 Power Reactor and Nuclear Fuel Development Corporation Tokai Works (72) Inventor Shinichi Murakami 4-33 Muramatsu, Tokai Muramatsu, Naka-gun, Ibaraki Prefecture Power Reactor and Nuclear Fuel Development Corporation Tokai Works (56) References JP-A-60-260894 JP, A) JP 42-9646 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B07B 1/10 G21C 21/02

Claims (5)

(57) [Claims] 1. An atomizer for separating and recovering mixed pellet fragments, powders, etc. from fuel pellets continuously supplied through a manufacturing process of fuel pellets for a nuclear reactor, and sending only non-defective pellets to a subsequent stage. An apparatus for sorting fuel pellets for a furnace, comprising: an endless wire mesh belt conveyor in which a pellet conveying surface is formed of a wire mesh for sieving; a knocker for vibrating the conveying surface of the conveyor; and a wire mesh belt conveyor. It consists of a trough that has been housed and has a debris discharge port opened at the bottom. The pellets supplied on the wire mesh belt conveyor are sieved into non-defective pellets, debris, and powder during the belt transport process. Fuel pellets for nuclear reactors, characterized in that the pellets are collected from the discharge port and non-defective pellets are sent from the end of the wire mesh belt conveyor to the subsequent stage. Door of the sorting apparatus. 2. The sorting apparatus according to claim 1, wherein a rib-shaped scraper is provided on the periphery of the wire mesh belt conveyor, and the fragments and powder of the pellets dropped on the bottom surface of the trough by the orbital movement of the scraper are discharged. An apparatus for sorting fuel pellets for a nuclear reactor, wherein the fuel pellets are raked and collected at an outlet. 3. An atomizer for separating and recovering mixed pellet fragments, powders, etc. from fuel pellets continuously supplied through a process for producing fuel pellets for a nuclear reactor, and sending only good-quality pellets to a subsequent stage. A furnace fuel pellet sorting device, in which the pellet conveying surface is composed of a wire mesh for sieving, the pellet supply side end is fixed, and the other end is a free end. A wire mesh belt, a wave generating mechanism for applying a wave motion to the wire mesh belt from the upstream side to the downstream side of the pellet conveyance, a trough containing the wire mesh belt and the wave generating mechanism, and having a debris discharge port opened on the bottom surface. The pellets supplied on the wire mesh belt are conveyed forward by the wave motion of the belt, and in the conveying process, the non-defective pellets, debris and powder are sieved, and the debris and powder are transferred to the traverse. It recovered from the discharge port dropped within, sorting apparatus for a nuclear reactor fuel pellets, characterized in that the non-defective pellets so as to output to the subsequent from the end of the wire mesh belt. 4. A sorting device according to claim 3, wherein the wave generating mechanism carries a wire mesh belt and is laid on the lower surface side thereof, and the back surface of the wire mesh belt dispersed on the chain circumference of the mechanism. And a rib-shaped wave-providing plate that slides on the surface of the trough, and the wave-providing plate is used as a scraper to scrape and collect the pellet fragments and powder that have fallen to the bottom of the trough by the orbital movement to the discharge port. An apparatus for sorting fuel pellets for a nuclear reactor. 5. An apparatus according to claim 2, wherein a soft pad is provided at a tip of the scraper.