Storage device

Abstract

Position-indexed storage device comprising a support and a basket installed on the support, the basket comprising a plurality of compartments distributed around a longitudinal axis, the basket comprising a central passage with a longitudinal axis, the support comprising a shaft with a longitudinal axis, the shaft being housed in the passage such that relative displacement is possible between the basket and the support along the longitudinal axis, and mechanical means for displacement of the basket relative to the support by a given angle about the longitudinal axis are supported by the internal surface of the passage and the external surface of the shaft, said mechanical displacement means being actuated in each cycle, each cycle comprising a relative separation or approach displacement along the longitudinal axis of the basket and the support.

Claims

1. A storage device for storing at least one nuclear material, the storage device comprising: a basket comprising a plurality of compartments distributed around a longitudinal axis and a central passage extended along said longitudinal axis, a support on which the basket is mounted, said support comprising a shaft extending along said longitudinal axis, the shaft being housed in the passage, the basket being configured to be displaced along said longitudinal axis and around said longitudinal axis relative to the support, and mechanical displacement means for displacing in rotation the basket relative to the support by a given angle about said longitudinal axis, said mechanical displacement means being disposed on comprised by an internal surface of the passage and an external surface of the shaft and configured to rotate the basket relative to the support during an operating cycle that comprises a relative separation displacement of the basket along said longitudinal axis and a relative approach displacement of the basket along said longitudinal axis.

2. The storage device according to claim 1, wherein the mechanical displacement means comprise: cam followers supported by the internal surface of the passage or by the shaft, and cams supported by either the shaft or the inside surface of the passage, said cams defining pairs of cam paths configured to guide the cam followers, said cam paths being distributed: in paths guiding cam followers during said relative separation displacement, called separation cam paths and in paths guiding cam followers during said relative approach displacement, called approach cam paths.

3. The storage device according to claim 2, comprising a first row and a second row each containing n cams, n being an integer equal to more than 1, arranged along the longitudinal axis, the n cams of each row being separated from each other by an angle 360/n about the longitudinal axis, the cams in the first row being offset by an angle equal to 180/n from the cams in the second row.

4. The storage device according to claim 2, in which the cam followers comprise rollers that project radially from the inside surface of the passage and the cams are supported by the shaft.

5. The storage device according to claim 3, in which the cams in the first row comprise at least one face inclined from the longitudinal axis and the cams in the second row comprise at least one face inclined from the longitudinal axis at an inclination opposite the inclination of the inclined faces of the cams in the first row, said inclined faces of the cams in the first row and second row being approximately facing each other.

6. The storage device according to claim 5, in which the cams in each first row and second row comprise faces parallel to the longitudinal axis delimiting the inclined faces such that two successive cams comprise two parallel faces providing longitudinal guidance of cam followers.

7. The storage device according to claim 6, in which each separation cam path and each approach cam path comprise a first longitudinal guidance portion, at least one skew guidance portion from the longitudinal axis and a second longitudinal guidance portion, in sequence along the longitudinal axis.

8. The storage device according to claim 7, in which a separation cam path and an approach cam path guiding the same cam follower have at least one longitudinal guidance portion in common, the skew guidance portions of the separation cam path and of the approach cam path having opposite inclinations.

9. The storage device according to claim 3 to comprising six compartments and in which n is equal to 6.

10. A handling system comprising: a storage device according to claim 1; and a displacement device for moving the basket relative to the support along the longitudinal axis.

11. The handling system according to claim 10, wherein the displacement device is configured to grip the basket and apply an up and down movement to it along the longitudinal axis, and the basket further comprises at least one means for being gripped.

12. The handling system according to claim 11, wherein the displacement device is a grab.

13. An installation configured for the fabrication of nuclear fuel, comprising at least one handling system according to claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) This invention will be better understood after reading the following description and appended drawings in which:

(2) FIG. 1 is a longitudinal sectional view of one example embodiment of a storage device according to the invention,

(3) FIG. 1A illustrates an arrangement in which the rollers are disposed on the shaft and cams are disposed in the passage.

(4) FIG. 1B illustrates an example of a grab as an external gripping means.

(5) FIG. 2A is a top view of the basket of a storage device in FIG. 1,

(6) FIG. 2B is a bottom view of the basket in FIG. 1,

(7) FIG. 3A is a side view of the indexing shaft alone,

(8) FIG. 3B is a cross-sectional view along plane A-A of the indexing shaft in FIG. 3A,

(9) FIG. 4 is a developed view of the indexing shaft of the device in FIG. 3A.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

(10) In the following description, the storage device will be described with reference to a transport canister for boxes filled with materials to be used for the fabrication of nuclear fuel.

(11) However, it will be understood that this is one example embodiment, and that this storage device may be used for storage of other objects, either in the nuclear field or in another field.

(12) FIG. 1 shows a longitudinal sectional view of an example embodiment of a device according to the invention. The device has a longitudinal axis X that will be oriented vertically.

(13) The storage device comprises a support 1 and a basket 2. The support 1 and the basket 2 in FIG. 1 are in a separated position. Also shown in FIG. 1 is a partial view of a confinement cell 3.

(14) FIG. 2A is a top view of the basket 2 that will contain empty canisters.

(15) In the example shown, the basket 2 is in the shape of a cylinder of revolution with axis X, comprising six compartments 4 distributed at uniform angles around the X-axis. An empty canister is in the form of a tube closed at one of its longitudinal ends; therefore it is elongated in shape. The shape of the compartments is such that it can hold canisters and canister heads.

(16) The number of compartments is not limitative and it may be less or more than six.

(17) Furthermore, in the example shown, the compartments do not comprise a closed sidewall, but the sidewall is open at the external periphery of the basket. The walls of the compartments are such that they surround the canisters sufficiently to hold them in place.

(18) The depth of the compartments 4 is such that they can hold the empty canisters. In the case of a basket to store canister heads, the basket may be the same as the basket used for canisters, and in this case several heads can be loaded in each compartment, or a basket with shallower compartments could be used in which each will contain a single canister head.

(19) The basket 2 comprises a passage 8 with axis X located at the centre of the compartments. The passage 8 opens up into the lower bottom 10 through a central opening 12.

(20) In the example shown, the top end 13 of the passage 8 is closed.

(21) Advantageously, the basket 2 comprises means 14 that will be used to handle the basket by an external system, for example by external gripping means, for example a grab 14a (see FIG. 1B) to move the basket 2 vertically. In the example shown, the means 14 are formed from a disk fixed at one of its faces to the top end 13 of the passage 8 by means of an axis 16 with diameter smaller than the diameter of the disk, such that the disk has a projecting radial edge 18 that can be used to grip it. For example, the grab is fixed to a travelling crane that moves it ready for use at another location of the installation.

(22) The lower opening 12 of the passage 8 comprises three rollers 20 around its periphery projecting radially inwards into the passage and arranged around the X-axis at 120 from each other, as can be clearly seen in FIG. 2B.

(23) The rollers 20 form cam followers as we will see later.

(24) The support 1 comprises a frame 24 that will be arranged approximately horizontally and an indexing shaft 26 with axis X oriented perpendicular to the chassis 24. The indexing shaft 26 will slide in the passage 8.

(25) FIG. 3A shows the indexing shaft 26 alone; this comprises a lateral surface comprising projecting cams 30.1 to 30.6 and 31.1 to 31.6, and defining cam paths along which the rollers 20 will slide.

(26) In the example shown and advantageously, the free end 26.1 of the indexing shaft 26 comprises a slender approximately frustum shape, facilitating its insertion into the passage 8.

(27) We will now describe details of one example embodiment of the cams and cam paths supported by the indexing shaft with reference to FIG. 4 that is a developed view of the lateral surface of the indexing shaft.

(28) The cams 30.1 to 30.6 and 31.1 to 31.6 are distributed in two rows R1, R2 along the X-axis, and there are six of each of them. The cams are numbered in increasing order around the anticlockwise direction.

(29) The two rows contain the same number of cams. Cams 30.1 to 30.6, 31.1 to 31.6 in each row R1, R2 are distributed at equal angles around the X-axis. Cams 30.1 to 30.6 in row R1 are offset by an angle equal to 30 from cams 31.1 to 31.6 in row R2. Thus, a cam 30.1 is located between two cams 31.1 to 31.6 along the direction of arrow F.

(30) FIG. 3B shows a sectional view of the indexing shaft 26 along plane A-A. The indexing shaft comprises six locations for the rollers defining the different angular positions that can be occupied by the basket 2.

(31) Each of the cams 30.1 to 30.6 in row R1 located on the side of the chassis 24 comprises a face 32.1 to 32.6 inclined relative to the X-axis located on the side of the free end 26.1 of the indexing shaft 26. In the example shown, the inclined face 32.1 to 32.6 is delimited by two faces 34.1 to 34.6 parallel to the X-axis and the inclined faces 32.1 to 32.6 form an angle of 45 with the X-axis.

(32) Cams 31.1 to 31.6 in row R2 located on the free end 26.1 of the indexing shaft comprise a face 36.1 to 36.6 inclined relative to the X-axis located on the side of the chassis 24 and with inclination opposite the inclination of the inclined face 32.1 to 32.6. In the example shown, the inclined face 36.1 to 36.6 is delimited by two faces 38.1 to 38.6 parallel to the X-axis and the inclined faces 36.1 to 36.6 form an angle of 45 with the X-axis.

(33) In the example shown, the cams 31.1 to 31.6 are in the shape of a non-rectangular parallelogram and therefore comprise a second inclined face 40.1 to 40.6 parallel to the inclined face 36.1 to 36.6 and located on the side of the free end 26.1 of the indexing shaft 26.

(34) The faces of the cams delimit cam paths in separation C1 guiding the rollers during a relative separation of the basket 2 and the indexing shaft 26 and approach cam paths C2 guiding the rollers during a relative approach of the basket 2 and the indexing shaft 26 (FIGS. 3A and 4).

(35) We will now describe operation of the storage device.

(36) As can be seen in FIG. 1, the basket 2 is mounted on the support such that the indexing shaft 26 is located in the passage 8, the rollers 20 then being located close to the chassis 24 of the support, each roller 20 is located between two cams 30.1 to 30.6.

(37) Consider a roller 20 initially located between the cam 30.1 and the cam 30.2. Therefore the roller 20 is located between the vertical faces 34.1 and 34.2.

(38) When the basket 2 has to be pivoted about its X-axis, a grab is lowered to grip the disk 14 and is then raised, causing upwards displacement of the basket 2 along the passage 8. The roller 20 then moves along the separation path C1, and thus slides firstly approximately vertically between the two vertical faces 34.1 and 34.2 of the two cams 30.1, 30.2 respectively, and then laterally and vertically along the inclined face 36.1 of the cam 31.1 and finally approximately vertically between two vertical faces 38.1 and 38.2 of cams 31.1 and 31.2 respectively.

(39) The basket 2 is then lowered, the roller 20 slides along the inclined face 40.2 of the cam 31.2, and then slides between the vertical faces 38.1 and 38.2 of the cams 31.1 and 31.2 respectively and then along the inclined face 32.2 of the cam 30.2, the basket 2 then pivots in the anticlockwise direction from its position. It can be seen that the roller 20 is now located between the vertical faces 34.2 and 34.3 of the cams 30.2 and 30.3 respectively, and is no longer between cams 30.1 and 30.2. Therefore, it has been rotated by 60 about the X-axis. Consequently, the basket has rotated by an angle of 60 in the anticlockwise direction about the X-axis.

(40) Thus, the indexing shaft 26 and the rollers 20 form simple and robust indexing means that do not require any electronic control. Moreover, the position of the compartments can be recorded by counting the number of displacements of the basket, and a compartment may be very simply associated with a canister or a canister head.

(41) With the invention, basket compartments are indexed uniquely mechanically without the use of an encoder or electronic processing means. Therefore, it is very robust and does not require any maintenance.

(42) In the example described, there are common portions in the paths C1 and C2, but it could be envisaged that the two paths do not have any common portions, for example the cams in row R2 could be such that during the approach phase, the roller 20 moves between faces 38.2 and 38.3 of rollers 31.2 and 31.3 and not between faces 38.1 and 38.2 of rollers 31.1 and 31.2.

(43) In the example described, the basket is rotated by displacement of the basket. Alternately, it could be envisaged that the support can be displaced downwards relative to the basket, the arrangement of cams along the X-axis would then be inverted relative to the arrangement in FIG. 3, or the basket and the support could be displaced in separation or in approach to each other.

(44) A device in which the rollers are supported by the shaft 26 and the cams are supported by an internal surface of the passage 8 is not outside the scope of this invention, particularly in the case of a large device. Such a device is illustrated in FIG. 1A, wherein the rollers 20a are disposed on the shaft 26a, for engagement with cams such as 30.1a and 31.1a disposed in passage 8.

(45) It could also be arranged that the basket is moved by a jack or any other system located under the basket or laterally and capable of moving the basket vertically relative to the support.

(46) It will be understood that the number of rollers is not limited to three. The use of three rollers has the advantage that it provides uniform guidance of the basket relative to the shaft.

(47) Furthermore, the profile and the number of the cams will be adapted as a function of the number of compartments in the basket. For example, in the case of a basket with eight compartments, the indexing shaft may comprise two rows of eight cams. However, the number of cams does not necessarily increase with the number of compartments. It could be arranged that several compartments are loaded simultaneously, for example two; thus a basket with twelve compartments would only need six different angular positions like the device described above.

(48) The use of the grab to displace the basket is particularly advantageous because the grab can be used for other purposes and therefore can be shared, which will reduce the manufacturing cost of the installation. For example for the case of storage baskets of empty canisters and canister heads that have been used for transport of boxes of materials for the fabrication of nuclear fuels such as plutonium oxide, the grab can also be used to handle the full canister ready for opening. It may also be used to move the full basket ready for evacuation.

(49) Therefore the storage device according to the invention can be applied to technical fields in which it is required to collect objects simply.