CH674276A5 - - Google Patents

Description

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PATENT CLAIMS area of its upper end arranged on it

1. A method for removing spherical fuel element gearwheel (31) via a member in engagement therewith from a cluster of balls which can be set in rotation within a reactive drive pinion (33). Core pressure vessel arranged cores, the Brennele- 6. Device according to claims 2 to 5, characterized mente over an inclined bottom surface of the core one Auss that at the mouth (12) of the Saugrohrlei-Iass and through this to a below of the device (10), a buffer provided surrounding the core with a radial spacing, protective tube (13) is connected, the inside diameter of which is characterized in that the intermediate storage corresponds to the outside diameter of the guide tube (18), takes place within the reactor pressure vessel, and the intermediate that during the upward stroke of the suction pipeline (10), the Feüh's memory is increasingly kept in a filled state by the protective pipe (13) by a certain amount of fuel-ele ment pipe (18) by an annular space defined by and the suction pipeline (10) (14) a number of fuel elements taken from the buffer store.

elements simultaneously by an equal number of fuel elements. 7. Device according to claims 4 to 6, thereby elements are replaced from the pebble heap, and that one is characterized in that lever arms (19) are springs which are used to continuously remove the fuel elements Pawls (17) which can be transferred into the annular space protrude pneumatically from the intermediate store via a suction pipe which is raised inside (14) and, when the guide tube (18) of the reactor pressure vessel enters, against the action of the springs from the annular space (14), through which the individual fuel elements successively can be urged, whereby the pawls (17) can be pivoted into a position outside the reactor pressure vessel in a position that frees the essentials parallel or axially to the central axis of the core in section of the line piece (11).

leads and there depending on different condition 8. Device according to claims 2 to 7, characterized by large and transferred into individual storage containers, characterized in that the suction pipeline (10) is led back into or into the core and the ball cluster of a fixed socket ( 20) guided protective tube (13) and immediately fed back. the guide tube (18), which in turn is guided therein,

2. Device from a below the core of a 25 can be continuously lifted out of the reactor pressure vessel. Reactor pressure vessel arranged intermediate storage, the

Spherical fuel elements can be loaded from the core via an outlet in an inclined bottom surface of the core, and a suction device connected to a conveying blower and proceeding from the intermediate store and guided vertically within the reactor pressure vessel. The invention relates to a method for removing pipeline, Via the fuel assemblies from the intermediate spherical fuel assemblies can be removed from a pellet store for carrying out the method of a device arranged within a reactor pressure vessel according to claim 1, characterized in that the intermediate and extends to a device for the feedthrough storage (8) completely within the reactor pressure reduction of the process.

is arranged and that the suction pipeline (10) with the removal of spherical fuel elements from their mouth (12) within the buffer of a core of a reactor, it is generally known that

(8) at least up and down moving drive is provided. Fuel elements over an inclined, preferably funnel-shaped

3. The device according to claim 2, characterized in that the bottom surface of the core is fed to an outlet, is characterized in that in the conveying direction to the mouth (12) of the 40, the reactor pressure vessel Brennele suction pipe (10) is connected to a line piece (11) by means of elements one is the bottom of the reactor pressure vessel, in the intrinsically free cross-section of the penetrating shaft which projects through to one below the core and holding elements. The pressure accumulators passed under the pressure of the intermediate downward stroke of the mouth (12) provided below the reactor pressure vessel through the suction pipeline, from which the fuel elements (3) pressed (10) take the cross section 45, checked and then in dependence from the position releasing the line piece (11), the various state variables determined are pivotably sorted, whereas the fuel elements are sorted by the holding elements in order to counteract the suction effect in the line piece (11) in the case of a so-called MEDUL-description (3) (MULTIPLE DURATION) ) once again delivered to the core are stable. or in the case of a so-called OTTO loading (once

4. Apparatus according to claim 3, characterized thereby to be removed through then out).

is characterized by the fact that the holding elements consist of pawls (17), which are mounted in the wall of the lei. Because of the sub-piece (11), the pawls (17) are evenly spaced both over the circumference and in a considerable space below Reactor pressure vessel - also distributed over the length of the line section (11), which places a cost-increasing enlargement of the reactor, its distances being connected in the axial direction of the containment. In addition, however, the line section (11) also corresponds approximately to the diameter of the ball conveyor for the removal of the fuel elements from the core in the fuel element (3), while the opening of the pawls (17) facing the bottom of the reactor pressure vessel faces the stop in the holding position From a safety point of view, there are considerable disadvantages in a circle whose diameter is smaller than that of the known extraction systems, the diameter of the fuel assemblies (3). 60 components to be provided half of the reactor pressure vessel

5. Device according to claims 2 to 4, thereby nenten, such as. B. separator and break separator and characterized in that the suction pipe (10) in a fixed- not interchangeable turntable.

standing guide tube (18) can be moved up and down and the invention has for its object the removal

to improve in the area of the type of the type described at the beginning of the buffer (8),

turned on the outside with a thread (21) 65 that a breakthrough in the pressure vessel bottom is avoidable, on which there is no rotation against a lid (26) of and below the bottom of the reactor pressure vessel

Reactor pressure vessel attached threaded nut (22) is seated, internals are to be provided for the removal, whereby and that the suction pipe (10) by the same on the one hand the safety of conventional reactor

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were significantly improved and on the other hand their height can be kept much lower.

To solve this problem, a method of the generic type mentioned in the preamble of claim 1 is assumed and proposed to proceed according to the invention according to the features specified in the characterizing part of the same.

Since the storage of the fuel elements according to the invention takes place within the reactor pressure vessel, a breakthrough in the bottom of the reactor pressure vessel which impairs safety is not necessary for removing the fuel elements from the core. If, according to the invention, the intermediate store arranged below the core, but above the bottom of the pressure vessel, is kept filled by a certain amount of fuel elements by replacing a number of fuel elements removed from the intermediate store from the pebble, no moving parts are required in the inaccessible one Area below the core to regulate the amount of balls that can be removed. Instead, this regulation takes place according to the invention by the discontinuous removal of the fuel elements from the intermediate store.

This can be arranged within the reactor pressure vessel in such a way that it is easily accessible for a suction pipeline which can be raised in a known manner without hindrance within the reactor pressure vessel. Via this suction pipeline, the fuel elements still inside the reactor pressure vessel according to the invention can be successively transferred from the intermediate store essentially parallel or axially to the central axis of the core into an area outside the reactor pressure vessel. There, the fuel elements can then be sorted according to condition sizes in an easily accessible, radiation-shielded area, the removal components required for this being subjected to mechanical stresses being easy to maintain and, in the event of a malfunction, also being repairable or replaceable.

The method according to the invention thus leads to a considerable increase in reactor safety, since there is no breakthrough in the bottom of the pressure vessel, and moreover enables considerable structural advantages due to a significantly lower overall height.

A device according to the preamble of claim 2 is suitable for carrying out the method, which has the features specified in its characterizing part.

Due to the fact that the intermediate store is arranged entirely within the reactor pressure vessel according to the invention, the spherical fuel elements to be removed remain inside the reactor pressure vessel when they are transferred to the intermediate store and also during their intermediate storage, so that the bottom thereof can be formed without breakthrough. Due to the suction pipeline opening into the intermediate store, which can be moved up and down at least with its mouth part by a drive, fuel elements can be removed intermittently depending on upward and downward strokes, which means that the amount of withdrawal required per unit of time can be exactly maintained.

The fuel elements are preferably conveyed using primary helium and are based on the generally known principle that, when flowing around a body, frictional forces of the gas act on the body in the direction of flow. To keep the fuel assembly floating as a result of these forces, i. H. So that the weight of the fuel assembly matches the frictional force of the gas, a so-called critical flow rate is required, whereas any higher flow rate causes the fuel assembly to move in the direction of flow. Desired flow velocities can be set by pressure differences between the start and end point of the conveying path, but since pressure losses are largely determined by the mass being conveyed, it is important to ensure reproducible or defined conveying masses. H. ensure the number of fuel elements conveyed by the gas flow, in order to be able to precisely coordinate the compressor capacity in the extraction system.

From this theoretical consideration, efforts were made to successively remove individual fuel elements from the intermediate store.

15 In order to ensure such an individual removal of the fuel elements from the intermediate store, according to one embodiment of the invention it is provided to connect a line piece in the conveying direction to the mouth of the suction pipeline, in the free cross section of which 20 pivotally mounted holding elements protrude. According to the invention, these can be temporarily pivoted under the pressure of the fuel elements pressed through the suction pipeline during the downward stroke of the mouth into a position which releases the cross section of the line piece. Then the 25 fuel elements are held back by the holding elements against the suction effect in the pipe section.

As a result of this configuration, as a result of a downward stroke of the mouth of the suction pipeline, the line section can be loaded with a certain number of fuel elements 30, which are initially retained therein by the holding elements against the suction effect prevailing inside the suction pipeline. Only after an upward stroke and a renewed downward stroke of the mouth can further fuel elements be pushed into the line section and successively displace the fuel elements previously taken up by the line section in the conveying direction. As a result, the fuel elements inevitably come out of the area of the holding elements one after the other and are exposed to the suction effect unhindered piece by piece and are thus individually conveyed through the suction pipeline.

It goes without saying that the cross sections of the mouth, the line section and the suction pipe are otherwise adapted to the diameter of the spherical fuel elements with sufficient clearance, but this clearance is by no means so large that two fuel elements are more or less in the mouth or jamming line cross-section or even more than one fuel element can occupy the same cross-sectional plane of the conveyor line at the same time.

According to a further embodiment of the invention, the holding elements consist of pawls which are mounted in the wall of the line piece and which are arranged at uniform intervals, both over the circumference and over the length 55 of the line piece. The distances in the axial direction of the line piece correspond approximately to the diameter of the spherical fuel elements, while the mutually facing ends of the pawls lie in the holding position on a circle whose diameter is less than 60 than the diameter of the fuel elements.

This configuration allows, for example, three pawls arranged in the same cross-sectional plane to hold a fuel assembly and to hold between this pawl group and a pawl group spaced apart in the axial direction of the line 65 from, for example, three blades against the suction effect. Only when a fuel assembly reaches the last pawl group in the conveying direction, e.g. under the

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If the pressure of the subsequent fuel elements has passed, this will cause the pawl's holding elements to be prevented from unhindered due to the suction effect until the springs are accessible from the annular space, as a result of which the pawls lie in the area outside the reactor pressure vessel via a position which releases the cross section of the line section leads and can there according to state variables, such. B. degrees are pivoted.

its burn-up and the extent of any damage s Since the transfer of the pawls to the release position of its shape, are sorted. only in groups, d. H. that only in the same preferably the suction pipe arranged overall in a cross-sectional plane pawls up and down when the guide tube is standing up. For this purpose, the suction pipeline can be simultaneously transferred into the release position in the region of its intermediate end, and therefore, depending on the upper end facing away from the lifting speed accumulator, the jacks of the following can only be provided with threads one after the other on their outside. A group can then be brought into the release position, and the threaded nut is also attached, which is expediently fastened to fuel elements at appropriate intervals in a cover of the reactor pressure vessel. Released by zeln, so that the suction force can only affect a fuel element for conveying, which is attached to the suction pipeline and thus can be rotated in the area of the upper end.

the driving pinion is in engagement. Finally, one embodiment of the invention provides for the line to be set in rotation and, depending on the direction of rotation, to provide for the suction line to move up and down in a fixed direction. Protective tube guided by the socket and the protective tube

Due to the drive of the suction tube guide tube according to the invention, the guide tube is led completely out of the reactor

tion can be lifted up and down stroke in particular 20 pressure vessels.

expediently accomplish, with the Dre- This configuration ensures that not only hung the suction pipe around its longitudinal axis, the drive means for the suction pipe are accessible for maintenance and penetration of its mouth into the accumulation of Brennele repair purposes, but that the suction

ment in the buffer is much easier. pipeline along with all mechanical loads

It is of course also within the scope of the invention to remove the 25 individual parts completely removed from the reactor pressure suction pipeline with additional drive means and also to see these parts, through which movement of the suction and repair purposes is also accessible .

Grohrleitung perpendicular to its longitudinal axis is possible. In addition, due to this additional direction of movement of the intake manifold, the fact that the intake pipeline can be removed gives the possibility that the theoretically existing 30 can be excluded one after the other in several reactor vessels to prevent the spherical fuel elements from being sucked downwards the rounded edge of their mouth, especially if the withdrawal from the core of a reactor absolutely hits a fuel element in the center and, despite the container - as with batch loading - it does not evade by rotating the suction pipe, but rather proportionately long intervals is required and is crushed as the downward stroke progresses. In any case, during these intervals, the suction pipeline is essential for the end-of-life that all drive means are honest. This results in a particularly large host for the pipeline in an area outside of the economy of the reactor, because for several reactor vessels there is a pressure release vessel and this arrangement for a warning device can be sufficient.

maintenance and repair purposes are freely accessible. In the drawing is a device for performing

According to a further embodiment of the invention, the method according to the invention is shown on 40. They show: the mouth of the suction pipeline with a radial one

Connected surrounding protective tube, Fig. 1 shows a vertical section through the device in Kon-

Inside diameter is the outside diameter of the guide recipe;

2 corresponds to a horizontal section through the device, the guide tube increasingly one of the protective 45 according to FIG. 1;

3 and a vertical section through the intermediate storage takes. and the lower area of the suction pipe;

_ This embodiment according to the invention gives FIG. 4 a horizontal section along the line IV-IV of FIG

Suction pipe with its mouth an excellent Fig. 3;

Guiding and storage, since outer sliding surfaces of the suction pipe, as shown in FIG. 5, slide a horizontal section along the line V-V of the pipeline over the inner surface of the guide pipe, FIG. 3;

while also internal sliding surfaces of the at the mouth Figure 6 is a vertical section through the upper region of the connected protective tube over the outer surface of the suction pipe.

Slide the guide tube. It may be advantageous to Fig. 7 is a horizontal section along the line VII-VII

External surface of the protective tube in a sliding bush to SS Fig. 6;

lead, which sits in a channel for the suction pipe, so Fig. 8 is a horizontal section along the line VIII-VIII

that parts of the suction pipeline are not connected with the inner limiter of FIG. 6.

contact surface of the channel and can rub against it. As can be seen in FIGS. 1 and 2, is within a

In addition, the core 2 formed by the outer surface of the suction-cylindrical graphite jacket 1 and a plate-shaped pipeline and the inner surface of the protective tube 2 can be arranged, which is filled with spherical fuel elements 3 annular space into which the suction tube is filled during the upward stroke. The loading of the core 2 with the Brennele-the guide tube increasingly penetrates, use excellently, elements 3 takes place in the direction of an arrow 4, but not according to - According to a further embodiment of the invention, the distribution organs provided have a lever across the horizontal, that is, by springs into the Holding position 65 cut the core 2 to ensure uniform loading, projectable jacks protrude into this annular space. The core 2 is delimited at the bottom by a funnel-shaped upward stroke of the suction pipeline and thus at the front floor 5, by means of which the fuel elements 3, due to the penetration of the guide tube into the annular space, displaces gravity in a manner that is arranged coaxially to the core 2.

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strive for the outlet shaft 6, at the lower end of which is connected a connecting shaft 7 which is inclined by approximately 45 ° and which opens into a buffer store 8,

which is arranged to the side of the core, but is clearly at a lower level with its uppermost region than the lowest region of the core 2. The fuel elements 3 will therefore keep the buffer 8 permanently filled due to the force of gravity alone.

A channel 9, which is aligned vertically above it, opens into the intermediate store 8 and axially a suction pipe 10 can be moved up and down.

The arrangement shown in FIGS. 1 and 2 and described above is located overall within the graphite jacket 1, which in turn is enclosed in a reactor pressure vessel, not shown, the bottom of which therefore does not require a breakthrough for the removal of the fuel elements 3.

As shown in FIG. 3, through a downward stroke of the suction pipeline 10, it has penetrated into the intermediate store 8 with a line section 11 and has incorporated a number of fuel elements 3 via an orifice 12. A protective tube 13 adjoining the mouth 12 surrounds the suction pipeline 10 with the line piece 11, forming an annular space 14.

3 and 5 show that the wall of the line section 11 has three longitudinal slots 15 distributed uniformly over the circumference, two of which are shown in FIG. 3 for reasons of simplification, in contrast to FIGS. 4 and 5, as diametrically opposite .

Pawls 17 designed as holding elements are pivotably mounted in the slots 15 about horizontal axes 16 and can be moved into the horizontal position shown by springs, not shown, against stops which are likewise not recognizable. The pawls 17 are designed as two-armed levers and, in the position shown, protrude at one end into the cross section of the line piece 11 and undertake a fuel element 3 in each case in a group of three arranged at the same height. Likewise, the group of three of the pawls 17 arranged above a fuel element 3 prevents that the fuel assembly 3 passes through the pawls 17 in question as a result of a flow acting in the suction pipe in the conveying direction, since they would have to be pivoted out of the cross-section of the line piece 11 against the spring action, for which purpose the suction effect prevailing in the line piece 11 is inadvertently not sufficient.

Only when the upward stroke of the suction pipeline 10 continues does a guide tube 18 enclosing it increasingly penetrate into the annular space 14 and successively displace lever arms 19 of the pawls 17 which protrude into the annular space 14. As a result, the pawls 17 are pivoted in groups one after the other from the horizontal position shown in FIG. 3 to a more or less vertical position so that they release the inner cross section of the line piece 11 and the fuel elements 3 are conveyed upward by the suction effect in a corresponding time sequence. The upward stroke of the suction pipeline 10 can be regarded as ended as soon as the guide tube 18 has displaced the lever arms 19 of the second lowest group of the pawls 17 from the annular space 14. Then the lowest fuel element 3 still contained in the line section 11 is exposed to the suction effect and is carried up via the suction pipe 10.

This is followed by a downward stroke of the suction pipe 10, a renewed loading of the line section 11 s with a number of fuel elements 3, which are pushed into the line piece 11 one after the other via the mouth 12, the pawls 17 against the spring action as long as the fuel elements 3 from the cross section of the Line piece 11 are pivoted out until the downward stroke is ended and no more fuel element 3 pushes up the fuel elements already in line piece 11.

A centered upward and downward movement of the suction line 10 is ensured by a fixedly arranged guide bushing 20 surrounding the protective tube 13.

In order to accomplish the drive for the upward and downward stroke of the suction pipeline 10, as can be seen from FIGS. 6 to 8, this is provided with a thread 21 in the area of its upper end on its outside. A nut 22 screwed thereon, consisting of two nut halves which are braced against one another to limit play, is enclosed by a sleeve 23 and welded firmly therein. At its lower end, the sleeve 23 is welded to a flange 24 which is fastened by means of screws 25 to a cover 26 of the reactor pressure vessel. In the same way, a flange 27 enclosing the upper end of the guide tube 18 is welded to it and fastened to the cover 26 by means of screws 28.

6 and 7 in particular, the suction pipe 30 line 10 is provided on the upper end piece with a wedge profile 29, on which there is a correspondingly profiled bearing bush 30 on the inside of a gear wheel 31 firmly connected to it. The suction pipeline 10 is thereby coupled to the gear 31 in a rotationally fixed manner, 35 whereas an axial displaceability of the suction pipeline 10 relative to the gear 31 is ensured. The bearing bush 30 is rotatable in a bearing 32 which is flanged onto the upper end of the sleeve 23.

The gear 31 is in engagement with a drive pinion 33, which is seated on a drive shaft 34, shown broken off, which is rotatable in a bearing 35. The drive pinion 33, which is provided with a reduction toothing in relation to the gear wheel 31, is encapsulated in a housing 36 covered by the bearing 35, which represents a lateral bulge of the sleeve 23.

The gear 31 is driven by a motor (not shown) via the drive shaft 34 and the drive pinion 33 fastened thereon, as a result of which the suction pipeline 10 executes an upward or downward stroke depending on the direction of rotation. In the position shown, the downward stroke of the suction pipeline 10 has ended. In this position, the upper end of the suction pipeline 10 is coupled to a connecting line 37, shown broken off, for which purpose it penetrates into the suction pipeline 10 with an end piece. During the upward stroke of the suction pipeline 10, the connecting line increasingly penetrates into the suction pipeline 10, so that a coupling with the connecting line 37 is ensured in every position of the suction pipeline 10, via which the combustion elements 3, not shown, for their condition assessment, sorting and Storage or reuse can be supplied.

40

B

5 sheets of drawings