US3173320A

US3173320A - Machine for separating irradiated fuel slugs from their jackets

Info

Publication number: US3173320A
Application number: US146022A
Authority: US
Inventors: Dabernard Pierre; Guilloteau Rene
Original assignee: Commissariat a lEnergie Atomique CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 1960-06-13
Filing date: 1961-06-13
Publication date: 1965-03-16
Anticipated expiration: 1982-03-16
Also published as: CH370492A; GB934622A; LU40234A1; DE1280427B; NL265865A; FR1267862A; BE604631A

Description

March 9 P. DA'BERNARD ETAL MACHINE FOR SEPARATING IRRADIATED FUEL swcs FROM THEIR JACKETS 4 Sheets-Sheet 1 Filed June 15, 1961 March 1965 P. DABE RNARD ETAL 3,173,320

MACHINE FOR SEPARATING IRRADIATED FUEL SLUGS FROM THEIR JACKETS Filed June 13, 1961 4 SheecsSheet z March 1965 P. DABERNARD ETAL 3,173,320

momma FOR SEPARATING IRRADIATED FUEL swcs FROM THEIR JACKETS Filed June 13, 1961 4 Sheets-Sheet 3 March 16, 1965 P, DABERNARD ETAL 3,173,320

MACHINE FOR SEPARATING IRRADIATED FUEL SLUGS FROM THEIR JACKETS Filed June 15, 1961 4 Sheets-Sheet 4 United States Patent 9,81 2 Claims. c1. 33-102 The present invention relates to methods and machines for separation from their jackets of nuclear fuel slugs that have been used in a nuclear reactor, this separation being necessary to permit subsequent reprocessing of the fuel, and in particular extraction of plutonium therefrom. This invention is more especially concerned with methods and machines of this kind, in which the jacket is first out along two longitudinal lines (cutting operation), after which the fuel slug is pushed out from the jacket through a hole provided in a separator member and having a cross section practically identical to that of the slug, this last operation being hereinafter called extrusion.

The object of the present invention is to improve such methods and machines so as to reduce the number of operations necessary for the above mentioned separation.

According to this invention, the jacket cutting operation is performed after the jacketed slugs have been placed in position for the extrusion operation.

Other features of our invention will become apparent in the course of the following detailed description thereof with reference to the appended drawings, given merely by way of example and in which:

FIG. 1 is a diagrammatic plan view of a machine made according to the invention;

FIG. 2 is a longitudinal elevational view of this machine;

FIGS. 3, 4 and 5 are sectional views on the lines IlIIIl, IV-IV and VV, respectively, of view 2;

FIG. 6 is a partial plan view, with parts cut away, of the same machine.

It is known, in order to separate an irradiated fuel slug from its jacket, first to out said jacket along two longitudinal lines thereof and then to push the fuel slug from the jacket thus slit by extrusion through a hole provided in a separator member, the cutitng operation greatly reducing the force necessary to perform the extrusion operation.

Up to this time the two above mentioned operations were performed at two different places, and this required two successive positionings of the slugs still enclosed in their jackets and the conveying of every slug from the first place to the second one.

As these operations must be telecontrolled and generally take place under a thickness of water of about 50 cms. in View of the high radioactivity of the slugs, the separation of fuel slugs from their jackets required a succession of operations taking a lot of time and which could hardly be effected automatically.

According to this invention, one of the two above mentioned positionings and the conveying from one place to another are dispensed with by effecting the jacket cutting operation after it has been positioned for the extrusion operation.

We might push the whole of the jacketed slug through a cutting device including tools fixed in the longitudinal direction so as to bring the edge of the jacket against an annular separator member through which the slug would be pushed, the jacket remaining in abutment against said member. But the jacket, which is generally stiffened by means of fins, would risk to be broken into e amaze 1C pieces which would quickly soil the water in which the device is immersed.

Preferably, according to the embodiment of our invention illustrated by the drawings, jacket 1 (FIG. 1), which tightly surrounds slug 2, remains stationary during both of the cutting and extrusion operations. As a matter of fact, this jacket is held horizontally in a trough-shaped support 3 in line with the circular hole of a separator member 4, the edge of the jacket being in abutment contact with the edge of this hole.

Cutting of the jacket along two longitudinal lines thereof is obtained by moving toward the left two cutting wheels 5 mounted on a carriage 6 movable in the longitudinal direction. Extrusion is obtained by means of a push-rod 7 in line with slug 2 and which causes said slug to slide through its jacket (kept stationary by separator member 4) and through the hole provided in said separator member 4.

The displacements of carriage 6 and rod 7 are controlled respectively by two coaxial pistons 8 and 9 slidable independently of each other so as to form the movable elements of a double hydraulic jack. The cylinder 10 of this jack is fixed with respect to separator member 4 by means of four horizontal rods 11 which constitute rails for rollers 12 mounted on carriage 6.

The whole is immersed in water.

The operation of this machine is as follows:

Initially, the jacketed slug is positioned on support 3 to which it is fed by the action of gravity as it will be hereinafter explained. Pistons 8 and 9 here are in the positions shown by FIG. 1.

Fluid under pressure is then fed through pipe 15 so as to enter the space between pistons 8 and 9. As piston 9 cannot move toward the right, piston 8 moves toward the left, driving carriage 6 in this direction. The cutting wheels 5, carried by carriage 6 are dimensioned and positioned so that their respective cutting edges are of a distance from each other smaller than the external diameter of jacket 1 but just a little greater than the diameter of slug 2. These wheels, moving toward the left, first push the slug to bring its jacket into abutment against separator member 4 and then cut the wall of said jacket along two lonigtudinal lines diametrally opposed to each other.

At the end of this displacement cutting wheels 5 come to fit in corresponding recesses 13 provided in member 4.

Power fluid under pressure is then fed through pipe 16 to push piston 9 toward the left together with rod 7 which thus pushes slug 2 through the hole of separator member 4, this hole having a diameter slightly greater than that of the slug. At the same time, the two portions of the jacket separated by the cuts formed therein are moved away from each other.

The extruded slug is evacuated through an inclined gutter 14 into any suitable receiver.

Flu-id under pressure is then fed through pipe 17, which opens between pistons 8 and 9 in their present positions, so that piston 9 moves toward the right together with rod 7. The jacket is removed from support 3 through an ejector device. Fluid under pressure is then fed through pipe 18 to push piston 8 toward the right together with carriage 6. The parts of the machine have thus been brought back to their initial relative positions and a new operation can now be performed.

Of course, it is possible to operate on slugs of different diameters and lengths. It sufiices to adjust the position and dimensions of the parts of the machine.

FIGS. 2 to 6 further illustrate some of the details of the machine.

Cutting wheels 5 are freely rotatable on vertical pins 19, pivoted about vertical axes 23 rigid with carriage 6 carried by levers 22, respectively. The distance between Patented Mar. 16, 1965 is these pins 19 may be adjusted by means of cams 29 (FIG. 6), springs 21 constantly tending to apply levers 22 against these cams. Arrow 43 (FIG. 6) shows the direction of movement of carriage 6 during the cutting operation. Fixed graduated sectors 44 (FIGS. 4 and 6) permit of easily determining the angular position of pointi as to compel the jackets to occupy a correct longitudinal position.

In order to retract hopper 24 during the cutting operation, this hopper is pivotabie about a horizontal axis 26 (FIGS. 2 and 3) and said hopper is provided with two inclined surfaces 27 adapted to cooperate with roilers 28 mounted on carriage 6; thus, when the carriage is moving forward (that is to say toward separator member 4) hopper 24 is automatically retracted and when the carriage moves back in the opposed direction, the hopper returns to its initial position. A roller 29 (FEGS. 3 and 4) mounted under carriage 6 and urged in the downward direction by a spring 30 keeps the jackets applied against the bottom of support 3. A recess 35 of separator memher 4 constitutes a housing for this roller at the end of the movement of the carriage toward the left.

The jacket ejector device essentially comprises two parallel plates 31 of suitable outline (FIG. 3) adapted to slide in transverse slots 32 formed in support 3. These plates are mounted on a base 33 the displacements of which (preferably controlled hydraulically) are guided by rod 34.

The end of the machine that carries jack 10 is merely resting upon a frame 36 whereas the other end of the machine rests through two pivots 37' (FIG. 2) in two half-bearings 38 having a common horizontal axis and carried by side-plates 39 fixed to frame 36. It is thus possible quickly to separate the machine from said frame by pulling it upwardly through lugs 40. This action first rotates the whole about the axis of pivots 37 and these remove it upwardly. The machine can be brought back into position very simply.

As visible on FIG. 2 frame 36 and the whole of the machine are immersed in water 42 contained in a tank 41.

A grid 46 (FIG. serves to protect the movable parts of the machine.

Merely by way of indication, some data will now be given concerning the operations effected with the machine above described:

The cylindrical slugs of natural uranium have a diameter of 26 mm. and a length of 300 approximately;

The jackets, made of an alloy of magnesium and zirconium, have a radial thickness of 1.5 mm. and are provided with longitudinal wings;

The cutting wheels made of nickel-chromium hard steel;

The pressure of the oil fed to jack is kg./cm.

The force exerted upon the slug ranges from 3 to 8 metric tons;

The'speed of movement of the pistons is about 10 cm,/ second;

The time between two successive operations is about one minute.

In a general manner, while we have, in the above description, disclosed what we deem to be a practical and efficient embodiment of our invention, it should be well understood that we do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims. In particular, the pistons serving to control the carriage and the push rod are not necessarily coaxial with each other and also the displacements of the carriage and of the push rod might be obtained by mechanical systems making use of chains or cables.

What we claim is:

1. An apparatus for separating a nuclear fuel slug from its rigid cylindrical jacket opened at both ends which comprises, in combination, a fixed separator member provided with a hole of a cross-section identical to that of said slug and to that of the inner wall of said jacket, means fixed with respect to said separator member for holding a slug opposite said hole and in line therewith with said jacket in abutment at one end thereof against the edge of said hole, a carriage movably connected with said separator member for sliding displacements of said carriage parallelly to the longitudinal dimenseion of said slug, cutting tools mounted on said carriage for cutting said jacket along two longitudinal lines thereof, reciprocating means for moving said carriage toward said separator member and away therefrom, and second reciprocating means movable toward and away from said separator member for pushing said slug through said hole during the displacements of said last mentioned reciprocating means toward said separator member.

2. An apparatus for separating a nuclear fuel slug from its rigid cylindrical jacket opened at both ends which comprises, in combination, a fixed separator member provided with a hole of a cross-section identical to that of said slug and to that of the inner wall of said jacket, means fixed with respect to said separator member for holding a slug opposite said hole and in line therewith with said jacket in abutment at one end thereof against the edge of said hole, a carriage movably connected with said separator member for sliding displacements of said carriage parallellly to the longitudinal dimension of said slug, cutting tools mounted on said carriage for cutting said jacket along two longitudinal lines thereof, and a hydraulic jack having two pistons in line with each other and with said hole, said pistons being movable separately of each other, and rods connecting said two pistons respectively with carriage and with said slug pushing means.

References Cited in the file of this patent UNITED STATES PATENTS 429,292 Thatcher June 3, 1890 1,366,082 Knabe Jan. 18, 1921 2,046,341 McParlin July 7, 1936 2,099,084 Seckha-m Nov. 16, 1937 2,209,209 Ruby July 23, 1940 2,827,405 Evans Mar. 18, 1958

Claims

1. AN APPARATUS FOR SEPARATING A NUCLEAR FUEL SLUG FROM ITS RIGID CYLINDRICAL JACKET OPENED AT BOTH ENDS WHICH COMPRISES, IN COMBINATION, A FIXED SEPARATOR MEMBER PROVIDED WITH A HOLE OF A CROSS-SECTION IDENTICAL TO THAT OF SAID SLUG AND TO THAT OF THE INNER WALL OF SAID JACKET, MEANS FIXED WITH RESPECT TO SAID SEPARATOR MEMBER FOR HOLDING A SLUG OPPOSITE SAID HOLE AND IN LINE THEREWITH WITH SAID JACKET IN ABUTMENT AT ONE END THEREOF AGAINST THE EDGE OF SAID HOLE, A CARRIAGE MOVABLY CONNECTED WITH SAID SEPARATOR MEMBER FOR SLIDING DISPLACEMENTS OF SAID CARRIAGEPARALLELLY TO THE LONGITUDINAL DIMENSION OF SAID SLUG, CUTING TOOLS MOUNTED ON SAID CARRIAGE FOR CUTTING SAID JACKET ALONG TWO LONGITUDINAL LINES THEREOF, RECIPROCATING MEANS FOR MOVING SAID CARRIAGE TOWARD SAID SEPARATOR MEMBER AND AWAY THEREFROM, SAID SECOND RECIPROCATING MEANS MOVABLE TOWARD THEREFROM, AND SECOND RECIPROCATING MEANS MOVPUSHING SAID SLUG THROUGH SAID HOLE DURING THE DISPLACEMENTS OF SAID LAST MENTIONED RECIPROCATING MEANS TOWARD SAID SEPARATOR MEMBER.