GB1589711A

GB1589711A - Transportation containing for nuclear fuel elements

Info

Publication number: GB1589711A
Application number: GB2526878A
Authority: GB
Original assignee: Kraftwerk Union AG
Current assignee: Kraftwerk Union AG
Priority date: 1977-08-26
Filing date: 1978-05-31
Publication date: 1981-05-20
Also published as: FR2406292A1

Description

(54) TRANSPORTATION CONTAINER FOR NUCLEAR FUEL ELEMENTS (71) We, KRAFTWERK UNION AKTIENGESELLSCHAFT, a German company, of Mülheim (Ruhr), Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to transportation containers for nuclear fuel elements.

According to the present invention, there is provided a transportation container for nuclear fuel elements, including an inlet unit with a valve which may be locked in a closed position by a releasable locking device, the locking device being such that, in use, the locking device is, or can be, released when a coolant line is connected to the inlet unit.

In a transportation container according to the invention, inadvertent opening of the coolant line can be eliminated, with the result that accidental escape of the fluid coolant is prevented. Since the coolant is prevented from escaping, the danger of insufficient cooling of fuel elements in the container due to a lack of cooling fluid and resultant overheating should also be prevented.

The connection of a coupling member of the coolant line is advantageously fdrmed as a bayonet lock which closes by an axial and a rotational 'movement. In this connection, in one embodiment of the present invention, the locking device is released before the rotational movement commences.

Locking can take place in various ways. It is advantageous, however, if the locking device can be released by a fluid under elevated pressure which is supplied by a fluid line adjoining the coolant line. The locking device can then be released after the coolant line has been connected to the inlet unit.

The same fluid can serve the purpose, additionally, of opening the valve.

Preferably the inlet unit is constructed so that a coupling member of the coolant line can be connected to the inlet unit, the coupling member, in use, being inserted axially into the inlet unit and then being rotated so as to secure the coupling member and hence the coolant line to the transportation container, thereby either releasing the locking device or enabling the locking device to be released.

The valve may be opened by means of a fluid under elevated pressure which is supplied by a fluid line, which can adjoin the coolant line.

Preferably the valve includes a movable valve member which is not subjected to any substantial force due to the pressure of the coolant and which is resiliently biased into a closed position.

Preferably the locking device comprises a locking pin which passes through a recess or opening in the valve member and resilient biasing means urging the locking pin into a locking position in which the locking pin projects from a coupling surface of the inlet unit and the valve member is locked in its closed position, wherein, when a coupling member is connected to the inlet unit, the locking pin is urged back against the action of the resilient biasing means until it is flush with the coupling surface to release the valve member.

The valve member can include a piston portion which can be acted upon by the fluid at elevated pressure to open the valve.

In one embodiment, the valve comprises a resilient biasing means and a valve member which comprises a head section disposed outside a passageway for the coolant, a stem passing through a side wall of the passageway, and a closure section which is connected to the head section by the stem, which is disposed in the passageway, and which is urged against a valve seat by the resilient biasing means; and the locking means comprises a locking piston, a locking pin secured to or integral with the locking piston, second resilient biasing means acting on one side of the piston to urge the locking piston and pin into a locking position in which the locking pin engages the head section of the valve to prevent the valve being opened, and a chamber which is partially defined by the other side of the locking position, whereby, in use, when fluid at an elevated pressure is supplied to the chamber, the locking piston is urged back against the action of the second resilient biasing means to release the valve member.

In this embodiment the valve can include an actuating piston one side of which is acted upon by a third resilient biasing means and the other side of which can be subjected to the pressure of an actuating fluid to cause the actuating piston, against the action of the third resilient biasing means, to urge the valve member into an open piston, provided that the locking pin and piston have been released from the head section.

The valve can further include an additional piston which can be subjected to a fluid pressure to maintain the valve member in an open position, the additional piston either acting directly on the valve member or via the actuating pin.

For a better understanding of the present invention and to show more clearly how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure i shows a section of a transportation container for fuel elements according to the present invention; Figure 2 shows, on a larger scale, a section of an inlet unit in the transportation container; and Figure 3 shows, diagrammatically, an alternative embodiment of an inlet unit for the transportation container.

The transportation container 1 for fuel elements comprises a cylindrical casing 2 which can be provided with ribs 3 and is provided with lifting lugs 4 at its upper and lower ends. The cylindrical casing 2 is closed at the bottom by a base 5 which is made of the same material as the casing, for example a C steel or carbon steel. There is at the upper end of the casing 2 an opening 6 for loading and unloading fuel elements which is normally sealed with a two-part cover 7.

There is coaxially disposed in the cover 7 a port 8 for connection to a cooling unit. An inlet unit 9 is provided below in the region of the base 5.

Figure 2 shows on a larger scale, one embodiment of the inlet unit 9 connected to the coupling member 10 of a cooling unit.

An insert 12 is secured by means of screws 13 in an opening 14 of the base 5. The insert 12 defines an opening 15 and a valve seat 16 which may be closed by a valve 17. The valve 17 is normally in the closed position shown, due to the action of a spring 8.

A shaft 20 of the valve 17 is guided in a bore 21 such that its end surface forms a piston 22. The shaft 20 is furthermore provided with an indentation or recess 23 which is shown by dotted lines in Figure 2. A locking pin 24, which is urged to the right by a spring 25, can engage the shaft 20.

There is provided, for the connection of the coupling member 10 of a coolant line 27 in Figure 2, a bayonet lock 28 comprising a flange 29 of the member 10 and projections 30 of the insert 12. In order to couple the coolant line 27 to the insert 12, the coupling member 10 is inserted axially in the direction of the arrow 31 and then rotated in the direction of the arrow 32 until the flange 29 is secured behind the projections 30. Thus the coupling is effected by means of a con ventional bayonet lock.

When the coolant line 27 is inserted in the direction of the arrow 31, the part of the locking pin 24 which, under the action of the spring 25, projects beyond a sealing surface 34, is forced back from the position shown by a dotted line 35. Consequently the locking portion 36 moves out of the recess 23 and frees the shaft 20. The valve 17 is then mechanically unlocked. The valve 17 can now be opened. The part 22 of the shaft 20 acting as a piston, is acted upon via a compressed-air line 37 which is structurally integral with the coolant line 27, with the result that the valve 17 is lifted from the valve seat 16 against the action of spring 18.

The invention prevents coolant from escaping out of the transportation container when there is no coolant line connected, for the purpose of receiving the possibly contaminated coolant. Opening of the valve 17 is prevented by the locking pin 24, when the coolant line 27 is removed. The locking pin 24 is unlocked by attaching the coolant line 27, with the result that opening of the valve is made possible without any additional procedure. The inlet unit, which includes the valve 17 is located in a recess of the transportation container and is thereby protected from damage.

Figure 3 shows another embodiment of an inlet unit 40 including a coolant connection which may be shut-off. The valve 41 comprises a movable valve disc 42 which is urged by a spring 43 against a valve seat 44.

The connection between the interior 45 of the transport container 1 and the part 46 of a coolant line 47 which leads outwards is thereby sealed.

The valve disc 42 is provided with a stem 48 with a head section 49 which engages with a locking pin 50 which can secure the valve disc 42 in the closed position shown.

The locking pin 50 is provided with a piston 51. The latter is acted upon by a spring 52 which forces the locking pin 50 to the left in the locking position. The front side 53 of the piston 51 can be acted upon by a pressure medium, for example, by compressed air, from a line 55, so that unlocking takes place.

The compressed air is supplied from a duct integral with the coolant line so that the locking pin 50 can only be disengaged from the head section 49 after the coolant line (not shown) has been coupled to the inlet unit 40.

An actuating piston 57 can act on the shaft 48, the piston being urged by a spring 58 into a lower position corresponding to the closed position of the valve 41. For the purpose of opening the valve 41, the piston surface 59 is acted upon by a pressure medium via a line 60. Compressed air is preferably used for this purpose, with the result that the pistons 51 and 57 can be acted upon with the same pressure medium.

For the purpose of keeping the valve 41 open, a mechanical or pressure-dependent operating device 62 can be provided which is not shown in greater detail in Figure 3. It acts with a push rod 63 via the piston 57 on the shaft 48 in order to keep the valve in the open position after it has been opened.

As Figure 3 shows, there is provided at the side of the valve disc 42 which is away from the shaft 48, a cylindrical shoulder 65 whose diameter corresponds to that of the valve seat 44. With this shoulder, the valve disc is guided in a balance chamber 66. The balance chamber 66 ensures that no displacement forces are exerted by the coolant on the valve disc 42. Thus the valve disc 42 can be operated with limited and constant forces. These limited forces also allow light construction of the locking device.

WHAT WE CLAIM IS: 1. A transportation container for nuclear fuel elements, including an inlet unit with a valve which may be locked in a closed position by a releasable locking device, the locking device being such that, in use, when a coolant line is connected to the inlet unit, the locking device is, or can be, released.

2. A transportation container as claimed in claim 1, wherein the inlet unit is constructed so that a coupling member of the coolant line can be connected to the inlet unit, the coupling member, in use, being inserted axially into the inlet unit and then being rotated so as to secure the coupling member and hence the coolant line to the transportation container, thereby either releasing the locking device or enabling the locking device to be released.

3. A transportation container as claimed in claim 1 or 2, wherein the valve may be opened by means of a fluid under elevated pressure which is supplied by a fluid line.

4. A transportation container as claimed in claim 3, wherein the fluid line adjoins the coolant line.

5. A transportation container as claimed in claim 1, 2, 3 or 4, wherein the valve includes a movable valve member which is not subjected to any substantial force due to the pressure of the coolant and which is resiliently biased into a closed position.

6. A transportation container as claimed in claim 5, in which the locking device comprises a locking pin which passes through a recess or opening in the valve member and resilient biasing means urging the locking pin into a locking position in which the lock ing pin projects from a coupling surface of the inlet unit and the valve member is locked in its closed position, wherein, when a coupling member is connected to the inlet unit, the locking pin is urged back against the action of the resilient biasing means until it is flush with the coupling surface to release the valve member.

7. A transportation container as claimed in claim 5 or 6, when appendant to claim 3, in which the valve member includes a piston portion which can be acted upon by the fluid at elevated pressure to open the valve.

8. A transportation container as claimed in any one of claims 1 to 4, wherein the valve comprises a resilient biasing means and a valve member which comprises a head section disposed outside a passageway for the coolant, a stem passing through a side wall of the passageway, and a closure sec tion which is connected to the head section by the stem, which is disposed in the pas sageway, and which is urged against a valve seat by the resilient biasing means to close the valve; and wherein the locking means comprises a locking piston, a locking pin secured to or integral with the locking pis ton, second resilient biasing means acting on one side of the piston to urge the locking piston and pin into a locking position in which the locking pin engages the head sec tion of the valve to prevent the valve being opened, and a chamber which is partially defined by the other side of the locking pis ton, whereby, in use, when fluid at an ele vated pressure is supplied to the chamber, the locking piston is urged back against the action of the second resilient biasing means to release the valve member.

9. A transportation container as claimed in claim 8, in which the valve includes an actuating piston, one side of which is acted upon by a third resilient biasing means and the other side of which can be subjected to the pressure of an actuating fluid to cause the actuating piston, against the action of the third resilient biasing means, to urge the valve member into an open position, pro vided that the locking pin and piston have been released from the head section.

10. A transportation container as claimed in claim 9, in which the valve includes an additional piston which can be subjected to a fluid pressure to maintain the valve member in an open position, the addi tional piston either acting directly on the valve member or acting via the actuating piston.

11. A transportation container substan tially as hereinbefore described with refer

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. unit 40. An actuating piston 57 can act on the shaft 48, the piston being urged by a spring 58 into a lower position corresponding to the closed position of the valve 41. For the purpose of opening the valve 41, the piston surface 59 is acted upon by a pressure medium via a line 60. Compressed air is preferably used for this purpose, with the result that the pistons 51 and 57 can be acted upon with the same pressure medium. For the purpose of keeping the valve 41 open, a mechanical or pressure-dependent operating device 62 can be provided which is not shown in greater detail in Figure 3. It acts with a push rod 63 via the piston 57 on the shaft 48 in order to keep the valve in the open position after it has been opened. As Figure 3 shows, there is provided at the side of the valve disc 42 which is away from the shaft 48, a cylindrical shoulder 65 whose diameter corresponds to that of the valve seat 44. With this shoulder, the valve disc is guided in a balance chamber 66. The balance chamber 66 ensures that no displacement forces are exerted by the coolant on the valve disc 42. Thus the valve disc 42 can be operated with limited and constant forces. These limited forces also allow light construction of the locking device. WHAT WE CLAIM IS:

1. A transportation container for nuclear fuel elements, including an inlet unit with a valve which may be locked in a closed position by a releasable locking device, the locking device being such that, in use, when a coolant line is connected to the inlet unit, the locking device is, or can be, released.

ence to and as shown in Figures 1 and 2 or Figures 1 and 3 of the accompanying drawings.

12. A combination of a transportation container as claimed in any one of the preceding claims, a plurality of fuel elements disposed inside the transportation container and a coolant line connected to the inlet unit of the transportation container.