GB2195571A

GB2195571A - Rotary severing device

Info

Publication number: GB2195571A
Application number: GB08623967A
Authority: GB
Inventors: Ronald William Calder Bain
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 1986-10-06
Filing date: 1986-10-06
Publication date: 1988-04-13
Anticipated expiration: 2006-10-06
Also published as: GB2195571B

Abstract

The device is used to sever elongate articles, such as nuclear fuel pins, into shorter lengths to expose the fuel inside the fuel pin and hence facilitate dissolution. The fuel pins 68 are fed through apertures 64, 66 in supporting members 62, 60 and urged against a rotatably driven hub 10 having circumferentially elongated holes 16, 22 which are provided with cutting edges by a blade 54. When the hub 10 rotates into a position such that an aperture 66, 64 registers with a hole 16, 22 in the hub 10, the fuel pin in that aperture 66, 64 passes through the hole 16, 22 until arrested by a stop 24. Further rotation of the hub 10 causes the blade 54 to sever the fuel pin. The holes 16, 22 are flared to allow the severed portions of fuel pin to fall out of the holes 16, 22 into a container. One, or more than two, cutting holes may be provided. <IMAGE>

Description

SPECIFICATION Rotary severing device This invention relates to severing elongate articles into shorter lengths, and is particularly, but not exclusively, concerned with severing irradiated nuclear fuel pins into shorter lengths.

The fuel used in a nuclear reactor is contained within fuel pins typically made from stainless steel or an alloy of zirconium. After irradiation in the reactor the irradiated fuel is reprocessed by dissolving it in an acidic liquor and then performing a series of solvent extractions. In order to dissolve the irradiated fuel from within the fuel pins the fuel pins are first cropped into small sections so that the fuel is exposed. The acidic liquor dissolves the irradiated fuel to leave behind the insoluble sections of fuel pin.

The object of the present invention is to provide an improved method and apparatus for severing elongate articles, such as irradiated fuel pins, into shorter lengths.

According to the present invention there is provided a method of severing an elongate article into shorter lengths, comprising feeding the article lengthwise along a predetermined path of travel towards a rotatably driven severing member arranged so that at least one cutting edge thereof sweeps across said path of travel during each revolution of the severing member to part off one or more portions of the article per revolution of the severing member.

The elongate article may be a fuel pin.

According to a second aspect of the present invention there is provided apparatus for severing an elongate article into shorter lengths, said apparatus comprising a severing member provided with at least one cutting edge, means for rotatably driving the severing member, and means for feeding the article lengthwise towards the severing member, the severing member being arranged so that, in use, the or each cutting edge sweeps across the path of travel of the article.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front view of a device for severing fuel pins; Figure 2 is a partly sectioned rear view of the severing device, showing the drive mechanism; Figure 3 is a section along the line Ill-Ill in Figure 2; and Figure 4 is a section along the line IV-IV in Figure 2 but with the hub rotated slightly from the position shown in Figure 2.

Figure 1 shows a rotatable hub 10 having holes 12, 14, 16, 18, 20 and 22 which are flared in the direction of fuel pin feed movement (see arrow X in Figure 3 and arrows A in Figure 4), circumferentially elongated and radially equidistant from the rotary axis of the hub 10. The holes 12, 14, 16, 18, 20 and 22 are arranged in pairs of substantially diametrically opposite holes. A stop 24 secured to a housing 28 by way of a support arm 26, is disposed at a predetermined distance from the hub 10 and is of such length that it covers two substantially diametrically opposite holes at a time as the hub 10 rotates.

Figure 2 shows the drive mechanism in more detail. An air motor 30 drives, via cou pling sleeve 34, shaft 36 which is mounted by bearings 38 and 40. The shaft 36 is provided with a worm gear 37 which engages the worm wheel 42 fastened to the outer edge of the hub 10 by bolts 50.

Referring to Figure 3, the hub 10 is rotatably mounted in a bearing bush 44 and is lo- cated axially within the housing 28 by a bolt 46 and bearing assembly 48. A blade 54 having circumferentially elongated holes 58 is fastened to the hub 10 for rotation therewith by bolts 56. Each hole 58 in the blade 54 is in registry with a respectve hole 12, 14, 16, 18, 20 and 22 in the hub 10.

Figure 4 shows the supporting means for the fuel pins. The housing 28 is provided with fuel pin supporting members 60 and 62 having apertures 64, 66, circular in cross-section, which register, in succession, with the holes in the blade 54 and hub 10 as the hub 10 rotates. In Figure 4 the apertures 64 and 66 are in registry with substantially diametrically opposite holes 58 in the blade and therefore with the holes 16, 22 in the hub 10. Fuel pins 68 are shown extending through the apertures 64, 66, holes 58, 16, 22 and in engagement with the stop 24. The substantially diametrically opposed holes 16, 22 in the hub and corresponding holes 58 in the blade 54 are circumferentially displaced from true diametral relationship so that the fuel pins 68 are severed sequentially as the hub 10 rotates.

In use fuel pins 68 are fed by, for example, power driven rolls located to the rear of the hub 10, such that the fuel pins 68 are fed towards the rotating hub in the direction of arrows A (Figure 4). The hub 10 is arranged so that its axis of rotation is parallel to the feed direction of the fuel pins 68 and also so that the holes 58 in the blade 54 sweep across the path of travel of the fuel pins 68 as the hub 10 rotates.

The air motor 30 acts through the worm gear mechanism to rotate the hub 10 and blade continuously. Fuel pins 68 are fed, one into each aperture 64, 66, and are continuously urged, by the power driven rolls, against the rotating blade 54. When the hub 10 rotates into a position such that the apertures 64, 66 register with a pair of substantially diametrically opposite holes 58 in the blade 54, the fuel pins which have entered apertures 64, 66 can then pass through the registering holes 58 in the blade 54 and the corresponding holes 12, 14, 16, 18, 20, 22 in the hub 10 until the pins are arrested by engagement with the stop 24. Further rotation of hub 10 causes the blade 54 to sever the fuel pins 68 sequentially, the supporting members 60, 62 acting as fixed blades.The holes in the blade 54 and hub 10 are circumferentialy elongated so that, for a given feed rate, a fuel pin 68 can pass through the holes and engage the stop 24 before the blade 54 engages, and severs, the fuel pin 68. The portions severed from the fuel pins 68 fall into the container, this process being facilitated by the flaring of the holes 12, 14, 16, 18, 20, 22 in the hub 10. Any stray particles of fuel or fuel pin are directed towards the container by a guard 32 which serves to protect the gearing. The remainder of each fuel pin 68 is urged against the blade 54 until the next pair of holes 58 in the blade 54 register with the apertures 64 and 66, when the severing process is repeated.

The length of fuel pin parted off can be altered by correlating the speed of rotation of the hub 10, the distance between the stop 24 and blade 54, and the rate of feed of fuel pin towards the hub 10.

The direction of rotation of the hub 10 may be reversed so as to even up wear on the cutting surfaces.

In use, the apparatus is located in a shielded cave. An air motor is preferred to eiectrical motors since fire hazards due to electrical sparking are eliminated and air motors are less prone to radiation damage.

It should be appreciated that the number of fuel pins fed towards the hub 10 is not limited to two and that further fuel pins could be fed for registry with the holes 12, 14, 16, 18, 20 and 22 at different positions around the axis of the hub 10.

In an alternative arrangement, the holes in the hub may be located at different radial distances from the rotary axis of the hub, with the fuel pins being fed towards the hub so as to register with these holes. There may be sets of holes in the hub, each set being located at different radial distances from the rotary axis of the hub, with one or a number of fuel pins being fed so as to register with each set of holes.

Claims

1. A method of severing an elongate article into shorter lengths, comprising feeding the article lengthwise along a predetermined path of travel towards a rotatably driven severing member arranged so that at least one cutting edge thereof sweeps across said path of travel during each revolution of the severing member to part off one or more portions of the article per revolution of the severing member.

2. A method as claimed in claim 1 in which the article is continuously urged towards the severing member.

3. A method as claimed in claim 1 or 2 in which the article is fed into a hole in the severing member, the hole being provided with a cutting edge so that the cutting edge engages the article on rotation of the severing member to sever the article.

4. A method as claimed in any one of the preceding claims in which the article is fed through an aperture in a non-rotatable article-supporting member located adjacent to the severing member for supporting the article during the severing operation.

5. A method as claimed in any one of the preceding claims in which the article is fed towards and engages with a stop before severing takes place.

6. A method as claimed in any one of the preceding claims in which the article is fed along said path of travel by power driven rolls.

7. A method as claimed in any one of the preceding claims in which the rate of feed of the article, speed of rotation of the severing member and position of the stop are selected so that the length of article is severed into portions of preselected length.

8. A method as claimed in any one of the preceding claims in which a plurality of articles are fed simultaneously towards the severing member along different paths of travel, each path being swept by the severing member as the latter rotates.

9. A method as claimed in claim 8 in which the articles are severed sequentially.

10. A method as claimed in any one of the preceding claims in which the article is a fuel pin.

11. A method of severing an elongate articie into shorter lengths substantially as hereinbefore described with reference to the accompanying drawings.

12. Apparatus for severing an elongate article into shorter lengths, said apparatus comprising a severing member provided wlth at least one cutting edge, means for rotatably driving the severing member, and means for feeding the article lengthwise towards the severing member, the severing member being arranged so that, in use, the or each cutting edge sweeps across the path of travel of the article.

13. Apparatus as claimed in claim 12 in which said apparatus is provided with a nonrotatable article supporting member located adjacent to the severing member and having at least one aperture for receiving and supporting the article while severing takes place.

14. Apparatus as claimed in claim 12 or 13 in which the severing member is provided with at least one hole through which the article can pass and the or each hole has a cutting edge associated with it.

15. Apparatus as claimed in claim 14 in which the severing member is provided with a plurality of holes having cutting edges.

16. Apparatus as claimed in Claim 15 in which the holes are substantially equidistant from the rotary axis of the severing member.

17. Apparatus as claimed in Claim 16 in which the feeding means is operable to feed a number of articles for registry with the holes at different positions around the axis of the severing member.

18. Apparatus as claimed in Claim 15 in which the holes are located at different radial distances from the rotary axis of the severing member and in which the feeding means is operable to feed a number of articles for registry with respective holes at said different radial distances.

19. Apparatus as claimed in any one of Claims 14-18 in which the holes are elongated in a circumferential direction.

20. Apparatus as claimed in any one of claims 14-19 in which the holes are flared in the direction of article feed movement so as to facilitate removal of the severed portions of article.

21. Apparatus as claimed in any one of the preceding claims in which said apparatus is provided with a stop for arresting the article with the leading end of the article in a predetermined position relative to the severing member.

22. Appar#atus as claimed in any one of Claims 12-21 in which the driving means comprises an air motor which drives a worm gear coupled with a worm wheel carried by the severing member.

23. Apparatus as claimed in Claim 22 in which said apparatus is provided with a guard to protect the gear arrangement.

24. Apparatus for severing an elongate articie into shorter lengths substantially as hereinbefore described and as shown in the accompanying drawings.