RU2634474C1 - Storage hood cover for spent thermal fuel assemblies of vver-1000 reactor and rod for its removal and placement - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: group of inventions refers to the means for storing defective spent fuel assemblies (SFA) of the VVER-1000 reactor. The storage hood cover for the spent fuel assemblies of the VVER-1000 reactor is mounted on the hood pipes by means of a bayonet connection and contains an inner ring, the sealing surface of which is pressed by a bayonet connection to the pipe flange, and a head, the outer contour of which corresponds to the outer contour of the SFA head. Plates with holes above the vertical grooves of the bayonet connection are connected to the cover, and fixing rods are mounted in the holes with the possibility of the vertical movement. There is also a rod for removing and placing the SFA storage hood.

EFFECT: remote control of the locking rods position.

6 cl, 5 dwg

Description

The invention relates to nuclear technology, in particular to means for storing defective spent fuel assemblies (SFA) of the VVER-1000 reactor, and is intended for use in spent nuclear fuel storage facilities at such fuel recovery plants or at nuclear power plants.

The FSUE “Mining and Chemical Combine” operates a wet storage facility where the SFAs of VVER-1000 reactors are stored in a water-filled pool. SFAs enter the pool in a transport case loaded into a protective container, from which in the overload compartment under the protective layer of water the SFAs are loaded into the storage covers with standard rods with grips that catch the SFAs over their heads.

Operational experience has shown that there are cases of SFAs in transport covers with a deviation of their heads from the vertical axis of the SFA with deformation of the guide channels connecting the head to the fuel part of the SFA, as a result of which the SFA cannot be engaged by standard rods.

In addition, the safety analysis performed also showed that when SFA is overloaded, there is a possibility of its falling to the bottom of the pool and, as a result, possible deformation of the SFA and its head, as well as loss of tightness of the fuel pipes.

To store such defective SFAs, a well-known case is intended for placement and storage of spent fuel assemblies of VVER-1000 reactors (see patent No. 2477899 G21C 19/06). The cover contains pipes provided with flanges in the upper part. Lids with inner rings are installed on the pipes by means of a bayonet fitting, the sealing surfaces of which are pressed by the bayonet fitting to the pipe flanges. The cover is equipped with a sealing ring, pressed by the bayonet connection to the flange of the pipe pipe. The covers are equipped with heads, the external contour of which corresponds to the external contour of the heads of the SFA, including their fixing elements (dowels or pins).

A well-known case is used to store defective SFA as follows. The SFA is installed in the cover tube depending on the defect of its head with a standard rod or devices for lifting and moving the defective SFA (see RF patents Nos. 2418320 and 2528398, IPC 7, G21C 19/32). Next, a cap is hung on a standard rod and mounted on the pipe, and with a subsequent rotation of the rod, the sealing ring of the cover is pressed against the pipe flange with a bayonet fitting.

After installing the covers on the pipes and pressing them on with a bayonet fitting, the water circulation through the pipes should cease, and the residual heat of the SFA is absorbed by the pool water due to heat transfer through the pipe walls. Gases resulting from the radiolysis of water are removed from the sealed volume of the pipe through a sintered metal filter.

The disadvantages of the cover of the known cover include the fact that the cover is not fixed in the position when its sealing ring is pressed against the pipe flange by means of a bayonet fitting of the cover with the pipe.

When removed from the cap head, the bar must be rotated in the opposite direction to align the head fixing elements with the vertical bar grooves, after which the bar can be lifted from the cap head. Due to the capture being under the protective layer of water and the length of the rod exceeding 10 m, it is possible to skew it and wedge the capture with a cover. The result is the possibility of a partial reverse rotation of the cap along with the grip and, as a consequence, the occurrence of a gap between the sealing surface of the inner ring of the cap and the pipe flange. As a result, water circulation through the pipes may occur, and if there is an unpressurized SFA in the pipe, pool pollution will occur. To control the position of the fixing elements of the pipe in the bayonet connection, which ensures that there is no gap between the sealing surface of the inner ring of the lid and the pipe flange, is almost impossible.

The cover of a well-known case is selected by the applicant as a prototype.

P-type rod, drawing K.7050.00.000 developed by the Federal State Unitary Enterprise Mining and Chemical Combine, contains a pipe hung on a hook of a lifting device, in the lower part of which there is a gripper for coupling the rod with the SFA, lifting it from the transport case and loading it into the storage case . The capture is made in the form of a cylindrical sleeve with a bayonet connection with a hooked SFA, in the form of two vertical parallel grooves for the entry of the SFA fixing elements (dowels or pins) and two samples shifted by 45 ° with grooves to accommodate the SFA fixing elements. A rod is placed inside the pipe, in the lower part of which a stop is installed, and in the upper part the rod is threadedly installed in a bevel gear of a bevel gear with a manual drive from the handle. When placing the SFA fixing elements in the grooves of the samples, the emphasis is lowered and fixes the SFA in the groove, which ensures the safety of the SFA transportation. Since the external contour of the cap heads corresponds to the external contour of the heads of the SFA, the well-known rod is used to set and remove the covers of the known cover.

Famous bar works as follows.

After installing the defective SFA in the tube of the case, the standard rod is removed from the pool and a cover is hung on it with the bayonet-head connection, which is fixed with a bevel gear in the grip. Further, the operator captures the rod with the cover is placed above the pipe so that the locking elements of the pipe are placed under the vertical grooves of the bayonet connection on the cover. The rod with the fixed cover is lowered until the fixing elements of the pipe are placed in the groove of the bayonet connection of the cover and rotated, while the sealing ring of the cover is pressed against the pipe flange by the bayonet connection. Next, the emphasis fixing the cap head in the gripper is lifted, removing the fixation of the cap head in the gripper, the rod is lowered until the locking elements exit the sample grooves and turned in the opposite direction to align the vertical grooves of the gripper with the locking elements of the head, after which the rod is removed from the cap head installed on the pipe cover.

Removing the cover from the pipe cover is as follows. The operator captures the rod is located above the cap head so that the locking elements of the cap head are placed under two vertical grooves on the grip. Then the bar is lowered until the fixing elements are placed in the grip sample and rotated until the head fixing elements are placed above the groove in the grip. Next, the rod is lifted so that the locking elements of the head enter the groove, and the rod is lowered until it touches the end surface of the cap head, fixing the cap in the grip. Then, by turning the rod, the fixing elements of the cover pipe are placed above the vertical grooves of the bayonet connection of the cover with the pipe and the cover fixed in the grip is removed from the cover pipe by lifting the rod.

A well-known full-time bar is selected by the applicant as a prototype.

The problem to which the alleged invention is directed is to create a cover fixed to the pipe of the cover and the possibility of its removal from the pipe cover.

The technical result that can be obtained using the proposed cover is its automatic fixation from rotation when it is placed on the pipe cover.

The specified technical result is achieved by the fact that in the cover of a well-known case, mounted on the tube of the case by means of a bayonet fitting containing an o-ring, pressed by the bayonet connection to the pipe flange, and a head, the external contour of which corresponds to the external contour of the SFA head, with holes are connected to the cover, located above the vertical grooves of the bayonet connection, and in the holes of the plates mounted fixing rods with the possibility of vertical movement.

In a particular case, the fixing rods in the upper part are connected by a ring.

In another particular case, stops with bevels are made at the lower ends of the fixing rods.

Attaching plates with holes located above the vertical grooves to the cover and installing fixing rods in the holes with the possibility of vertical movement allows the cover to be inserted into the freed vertical grooves of the bayonet joint when the cover is placed on the pipe and rotated in a bayonet joint, by gravity and fix the cover on the pipe tube against rotation.

The connection of the fixing rods in their upper part with a ring allows not only to ensure their simultaneous raising and lowering, but also allows you to visually check the position of the ring by introducing the fixing elements of the pipe into the vertical grooves of the bayonet connection, which ensures that there is no gap between the cap sealing ring and the pipe flange.

Performing stops at the lower ends of the fixing rods of the stops with bevels allows, due to the interaction of the bevels with the fixing elements of the pipe, by vertical action on the ring, an additional rotation of the cover is made and a more secure fit of the cover sealing ring to the pipe flange and the cover is fixed on the pipe from turning in the opposite direction.

The technical result, which can be obtained by using the proposed rod, is to create the ability to remotely change the position of the fixing rods of the cover.

The specified technical result is achieved by the fact that in the proposed rod, in contrast to the known one, cheeks are attached to the outer surface of the gripper, in the vertical grooves of which on the axes there is a slider with the possibility of vertical movement, and a rotary lever is installed on the lower axis of the slider. The slider is equipped with a vertical groove with an axis placed in it, on which earrings are mounted pivotally connected to the pivot arm, and a fork connected by a rope with a manual drive installed in the upper part of the rod.

In the particular case of execution, an additional load is attached to the slider.

In another particular case, the manual drive is made in the form of a latch attached to the upper part of the rod.

The installation of a rotary lever on the lower axis of the slider and supplying the slider with a vertical groove with an axis located on it, on which earrings are mounted pivotally with the rotary lever, and a fork connected by a rope with a manual drive installed in the upper part of the rod, allows manual movement with vertical movement fork up first, first carry out the vertical movement of the axis along the groove of the stationary slider having a greater mass and, due to the articulation of the earrings with the lever, ensure the rotation of the lever and its removal under a ring connecting the fixing rods on the cover.

Attaching the cheeks with the vertical grooves made to them to the outer gripping surface and installing the slider in the grooves on the axes with the possibility of vertical movement of the slider allows, when the fork axis reaches the end of the vertical groove in the slider and the fork is further lifted, it is possible to jointly raise the slider and the ring engaged by the rotary lever, resulting locking rods are derived from the vertical grooves of the cover.

Attaching an additional load to the slider facilitates the initial vertical movement of the axis along the vertical groove of the fixed slider and the rotation of the lever with its introduction under the ring connecting the fixing rods.

The implementation of the manual drive in the form of a bolt attached to the upper part of the rod, allows you to remotely fix the pivot arm, and therefore the locking rods of the cover in two extreme positions.

The invention is illustrated by drawings, which show:

in FIG. 1 is a sectional view of a non-fixed cover on a pipe tube;

in FIG. 2 - sectional view of a cover fixed with a pipe tube;

in FIG. 3 - the proposed bar in the context;

in FIG. 4 - gripping the rod with a cover when installing the cover on the pipe tube;

in FIG. 5 - capture of the rod when removing the cover from the pipe cover.

The proposed cover 1 (see Fig. 1 and 2) contains a stepped shell 2 with a sealing ring 3. In the lower part in the shell 2 on the diametrically opposite sides there are vertical 4 and inclined 5 grooves of the bayonet joint 6, interacting with the locking elements 7 attached to the pipe 8 of the cover 9. In the upper part, a head 10 is attached to the shell 2, the outer contour of which corresponds to the external contour of the SFA head, including its fixing elements 11. To the shell 2 are connected plates 12 and 13 with holes 14 located above the by vertical grooves 4. In the holes 14, fixing rods 15 are mounted, connected in the upper part by a ring 16. In the lower part, the fixing rods 15 are equipped with stops 17 with bevels 18 directed towards the fixing elements 7. The cover 1 is mounted on the pipe 8 and is pressed by its sealing ring 3 to the flange 19 of the pipe 8 by a bayonet connection 6. To the ring 16 also on the diametrically opposite sides are attached guide rods 20 located in the holes 14 of the plates 12.

The proposed rod 21 (see Fig. 3), hung on the hook of the lifting device (not shown in the drawings), contains a pipe 22, in the lower part of which is mounted a gripper 23 for engaging with the head 10 of the cover 1. The gripper 23 is made in the form of a cylindrical sleeve 24 with a bayonet connection 25 made in the form of two vertical parallel grooves 26 for the entry of the locking elements 11 of the cover 1 and two samples 27 with grooves 28 for placement of the locking elements 11. On the outside of the sleeve 24 are attached cheeks 29 with vertical grooves 30. Between the cheeks 29 on axes 31 and 32 with vertical movement, a slider 33 is installed, on the lower axis 31 of which a pivot arm 34 is mounted. The slider 33 is provided with a vertical groove 35 with an axis 36 located therein. On the axis 36, earrings 37 are mounted pivotally to the pivot arm 34, and a plug 38 connected by a cable 39 with a manual drive 40 mounted in the upper part of the pipe 22.

Manual drive 40 is made in the form of a latch 41 attached to the pipe 22 in its upper part. In the upper position, the handle 42 of the latch 41 is located in the groove 43, and in the lower - at the end of the groove 44. Inside the pipe 22 there is a rod 45, in the lower part of which there is a stop 46, and in the upper part the rod 45 is threadedly installed in the bevel gear 47 of the bevel gearbox 48 with a manual drive 49. If necessary, an additional load 50 can be installed on the slider 32.

The proposed cover 1 and the rod 21 are used as follows.

After installing the defective SFA in the pipe 8 of the cover 9, the setting of the cover 1 is carried out in the following order. The proposed rod 21 is removed from the pool and in its grip 23 using the bayonet connection 25 set the head 10 of the cover 1 and fix it in the grip 23 focus 45 (see Fig. 4). The handle 41 of the latch 40 is placed at the end of the groove 43, while the slider 33 with the pivoting lever 34 are in the lower position and placed under the ring 16 of the cover 1. The rod 21 with the fixed cover 1 is lowered into the pool. Next, the rod 21 with the cover 1 fixed in it is lowered until the fixing elements 7 are placed in the grooves 4 of the bayonet connection 6 of the cover 1, while the fixing rods 15 are supported by the fixing elements 7 of the pipe 8. Next, the rod 21 is rotated, while the fixing rods 15 of the cover 1 fall into the released vertical grooves 4, and the sealing ring 3 of the cover 1 is pressed against the flange 19 of the pipe 8 by a bayonet connection 6. To remove the rod 21 with the bevel gear 47 mounted and fixed on the pipe 8, the bevel gear 47 lifts the stop 45, fixing the casing 10 of the cover 1 in the grip 23, removing the fixation of the head 10 in the grip 23. The rod 21 is lowered until the locking elements 11 of the head 10 exit from the grooves 28 of the samples 27 and are turned in the opposite direction until the vertical grooves 26 of the grip 23 are aligned with the locking elements 11, after which the rod 21 is lifted from the cover 1, fixed on the pipe 8 of the cover 9 by the fixing rods 15.

The position of the ring 16 visually control the position of the locking elements 7 of the pipe 8 in the bayonet connection 6, which ensures that there is no gap between the sealing ring 3 of the cover 1 and the flange 19 of the pipe 8. If necessary, additional vertical impact on the ring 16, for example, the capture of 23 of the rod 21, due to the interaction of the bevels 18 of the fixing rods 15 with the fixing elements 7 of the pipe 8, it is possible to carry out an additional rotation of the cover 1 and a more reliable fit of the sealing ring 3 to the flange 19 and a reliable fixation the lid 1 on the tube 8.

If necessary, removing the cover 1 from the pipe 8 of the cover 9 is as follows. The operator captures the rod 23 of the rod 21 above the head 10 of the cover 1 so that its locking elements 11 are placed under two vertical grooves 26 on the capture 23. Then the rod 21 is lowered to place the locking elements 11 in the samples 27 of the capture 23 and rotate, while the locking elements 11 on the head 10 are located above the grooves 28 of the bayonet connection 25 of the gripper 23. Next, the rod 21 is lifted by introducing the locking elements 11 into the grooves 28, and with the help of a bevel gear 47, the cover 1 is fixed in the gripper 23 with an emphasis 45. Then the handle 41 latches 40 are lifted and transferred to groove 42 (see FIG. 5). In the process of lifting the bolt 40, first, the plug 37 connected to the bolt 40 by the rope 38 raises the axis 36 along the groove 35 of the fixed slide 33, and the earrings 37 mounted on the axis 36 move it to the upper position under the ring 16 due to the articulation with the pivoting lever 34. After stop axis 36 at the end of the groove 35, the fork 37 lifts along the vertical grooves 30 in the cheeks 29 and the slider 33 together with the ring 16 engaged by the pivot arm 34, as a result of which the locking rods 15 are removed from the vertical grooves 4 of the cover 1.

By turning the rod 21 with the cover 1 fixed in its grip 23, the fixing elements 7 of the pipe 8 are placed in the vertical grooves 4 and the rod 21 with the cover 1 is removed from the pipe 8.

Claims (6)

1. The cover of the storage cover of spent fuel assemblies of the VVER-1000 reactor, mounted on the pipe tubes by means of a bayonet fitting and containing an inner ring, the sealing surface of which is pressed by the bayonet fitting to the pipe flange, and a head whose external contour corresponds to the external contour of the SFA head, characterized in that that plates with holes located above the vertical grooves of the bayonet connection are attached to the cover, and fixing holes are installed in the holes with the possibility of vertical movement. 2. The cover according to claim 1, characterized in that the fixing rods in the upper part are connected by a ring. 3. The cover according to claim 1, characterized in that at the lower ends of the fixing rods made stops with bevels. 4. A rod for removing and inserting the cover of the storage cover of spent fuel assemblies of the VVER-1000 reactor, including a pipe hung on a hook of a lifting device, a grip installed in its lower part, made in the form of a cylindrical sleeve with a bayonet fitting with a cover hooked onto the head, placed in a conical gearbox with a rod and a stop, characterized in that the cheeks are attached to the outer surface of the gripper, between which a slider is installed with vertical vertical grooves on the axes moving, on the lower axis of the slider, a pivot lever is installed, the slider is equipped with a vertical groove with an axis placed on it, on which earrings are mounted pivotally connected to the pivot lever, and a fork connected by a rope with a manual drive installed in the upper part of the rod. 5. The rod according to claim 4, characterized in that an additional load is attached to the slider. 6. The rod according to claim 4, characterized in that the manual drive is made in the form of a latch attached to the upper part of the rod.

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