RU2564107C1 - Grid of case for storage of waste nuclear fuel - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: grid includes the following components connected to the base: a central pipe, vertical posts and cells for arrangement of ampoules with bundles of fuel elements, which are made in several coaxial tiers. In the base there are holes coaxial to symmetry axes of cells and a hole along the axis of the central pipe. Inside diameter of the central pipe is equal to inside diameter of cells, and the upper part of the central pipe is provided with a device for its engagement after removal of the ampoule from it.

EFFECT: possible arrangement in the central pipe of the ampoule with conditioned or non-conditioned bundle of fuel elements.

3 cl, 4 dwg

Description

The invention relates to the management of spent nuclear fuel, and more particularly to loading, transporting and unloading ampoules with bundles of RBMK-1000 reactor fuel elements from a transport case into dry storage cases.

There is a known method for handling spent nuclear fuel (patent No. 2491665, class G21F 19/06), including placing at the nuclear power plant bundles of fuel elements (fuel elements) in ampoules (patent No. 2353010, G21F 5/008), loading part of the ampoules with bundles of fuel elements in lattice cases located in the nests of the transport cover, and parts of the ampoules - in the cells of the cover located between the nests. In the case of a complete set of canisters (CCP) of the dry storage with a crane with a lifting capacity of 4000 kg, the lattices loaded with ampoules are alternately removed from the nests of the transport case and are installed in the cases of the cases, and the ampoules from the cells of the case are loaded one at a time with the help of an electromechanical manipulator with a lifting capacity of 500 kg.

After installing lattices with ampoules in the cases of the canisters and filling the lattice of the cans with ampoules from the cells of the transport case, the covers are installed on the cases of the canisters, they are connected to the cases by welding, vacuuming and filling of the canisters with excess pressure are carried out through the valve caps, after which the valves are sealed by welding. The loaded canisters are mounted by a crane with a crane, into the sockets of the reloading machine, with the help of which the loaded canisters are installed in the nests of the dry storage.

A known lattice of a sealed spent nuclear fuel storage case (see RF patent No. 2435239, IPC G21C 19/06, 2010), made in the form of a set of disks with coaxial holes forming cells for accommodating conditioned spent fuel rods. The disks are mounted on vertical racks, and an additional ampoule with a bunch of fuel rods is installed in the central hole of the grill.

The disadvantages of the known lattice include the fact that when implementing the transportation method according to patent No. 2491665, a pencil case with a known lattice can only be used to load individual ampoules placed in the cells of the transport case, due to the fact that the lattice cannot be removed from the pencil case and cannot be sent with a transport case to the NPP for loading ampoules with bundles of fuel rods into it.

Known lattice sealed storage case for spent nuclear fuel of the RBMK-1000 reactor according to patent No. 2491665.

The grill is made with the possibility of extracting a pencil case from the housing and installing it in the socket of the transport cover. The grate is equipped with a base with vertical posts attached to it and a central pipe, and cells for accommodating ampoules with bundles of fuel rods. The cells are made in several coaxial tiers, consisting of tubular sleeves connected to the central pipe, vertical posts and between each other by plates with the formation of round and triangular cells. The axis of symmetry of the cells are located at the vertices of equilateral triangles, and the diameter of the inscribed circle of the triangular cells is equal to the inner diameter of the round cells. The ends of the plates located between the uprights are V-shaped. At the base, holes are made, coaxial with the axes of symmetry of the cells, and a fungus is installed in the central tube, which in shape resembles the fungus of the canister cover.

When removing the lattice from the nest of the transport cover, by gripping the crane, the lattice with ampoules is hooked onto the fungus mounted on the central pipe, removed from the transport cover and installed in the pencil case. Known lattice has 30 cells for placement of ampoules.

Known lattice adopted by the applicant as a prototype.

A disadvantage of the known lattice is that the design and dimensions of the central pipe do not allow placing an additional ampoule in it even after removing the fungus.

The technical result, which can be obtained by using the proposed lattice, is to perform a central pipe with the possibility of placing ampoules in it.

The specified technical result is achieved by the fact that in the lattice, including the central pipe attached to the base, vertical posts with plates attached to them and cells for accommodating ampoules with fuel rods bundles, made in several coaxial tiers, a base in which holes are made, coaxial with the axes of symmetry cells, the inner diameter of the central pipe is made equal to the inner diameter of the cells, a hole is made in the base along the axis of the central pipe, and the grill is equipped with a device for its engagement after extraction Nia ampoule of the central tube.

In the particular case of execution in the upper part of the central pipe, grooves are made according to the type of bayonet connection.

In another particular case, the execution of the cell lattice can be made with the possibility of installing them in ampoules with an increased diameter.

Performing the inner diameter of the central pipe equal to the inner diameter of the cells and making the hole in the base along the axis of the central pipe allows you to place the ampoule with the fuel rod bundle in the central tube when loading the ampoules, and thereby ensure the transportation of the lattice with the maximum possible number of ampoules.

Providing the lattice with a device for its engagement after removing the ampoule from the central tube allows the ampoule to be removed from the central tube in the CCP, to engage and transfer the lattice from the transport cover into the case of the canister, and then re-install this ampoule in the central tube and thereby ensure the filling of the canister storage with the maximum possible number of ampoules with bundles of fuel rods.

Performing grooves in the upper part of the central tube according to the type of bayonet connection allows, after removing the ampoule from the central tube, to engage the grating with a gripper.

The implementation of the grid cells with the possibility of installing ampoules with an increased diameter in them allows loading into ampoules, transportation and storage of substandard bundles of fuel elements.

The invention is illustrated by drawings, which depict:

in FIG. 1 - the proposed lattice in the context;

in FIG. 2 is a view A in FIG. 1 gratings for ampoules with conditioned bundles of fuel rods;

in FIG. 3 is a view A in FIG. 1 lattice with substandard bundles of fuel elements;

in FIG. 4 - the proposed lattice mounted on the Central pipe capture.

The proposed lattice 1 (see Fig. 1 and 2) contains a central pipe 2 and vertical posts 3 attached to the base 4. The lattice 1 contains several coaxial tiers 5, consisting of tubular sleeves 6 connected to the central pipe 2, vertical posts 3 and between each other by plates 7 with the formation of round 8 and triangular 9 cells, the axis of symmetry of which are located at the vertices of equilateral triangles. The diameters of the inscribed circles of the triangular cells 9 and the inner diameter of the central pipe 2 are made equal to the inner diameter of the round cells 8. At the base 4, holes 10 are made, coaxial with the axis of symmetry of the cells 8 and 9, and the hole 11 is along the axis of the central pipe 2.

In the central tube 2, grooves are made in the form of a bayonet lock, including vertical 12 and 13 grooves and a horizontal groove connecting them 14. In cells 8, 9 and the central tube 2, ampoules 15 with bundles of fuel rods are installed.

As a result of long-term storage in an on-site storage facility after being in a nuclear reactor at a nuclear power plant, there are substandard fuel assemblies with significant deviations from straightness and an increased outer diameter of the fuel rod bundle. To load substandard bundles of fuel rods, the use of ampoules 15 with an increased inner diameter is required, which, in turn, will require an increase in both the diameter of the cells 8 and 9 of the lattice and the step between them. Based on this, for transportation and storage of ampoules 15 with conditioned or substandard bundles of fuel elements, it is necessary to have cells 8 and 9 and a central tube 2 with different internal diameters in the removable grid.

The lattice for transporting standard bundles of fuel elements (see Fig. 2) contains six round 8 and twenty-four triangular 9 cells. Moreover, the inner diameter of the cells 8 and 9 and the central pipe 2 is 98 mm, and the maximum capacity of the lattice is 31 ampoules.

Measurements of substandard fuel rod bundles performed at nuclear power plants showed that for their placement in ampoules it is necessary to increase the internal diameter of the ampoules to 98 mm.

The lattice for transporting substandard bundles of fuel elements (see Fig. 3) contains six round 8 and twelve triangular 9 cells. Moreover, the inner diameter of the cells 8 and 9 and the central tube 2 of the lattice is 104 mm, and its maximum capacity will be 19 ampoules.

After removing the ampoule 15 from the central tube 2, a gripper 16 can be installed (see Fig. 4), the pins 17 of which, when installed, are successively inserted into the grooves 12, 14 and 13. The gripper 16 is equipped with a fungus 18 that repeats the fungus shape , in the upper part of which a bore 19 is made, in the form of a repeating ampoule cover. The gripper 16 is also equipped with a spring 20 and a protective collar 21.

The proposed lattice 1 is operated as follows.

The gratings 1, in the cells 8, 9 and the central tubes 2 of which empty ampoules 15 are installed, enter the nests of the transport cover at the nuclear power plant, where conditioned or non-standard bundles of fuel rods are placed in the ampoules 15. After the delivery of the transport case and its installation in the pencil box, the ampoule 15 is removed from the central tube 2 by the electromechanical manipulator and installed for temporary storage. Next, the gripper 16 is hooked to the bore 19 by the electromechanical manipulator, mounted in the central pipe 2 and rotated therein, while the pins 17 are sequentially inserted into the grooves 12, 14 and 13 of the central pipe and lifted by the spring 20, fully entering the grooves 13. The electromechanical manipulator disengages from a gripper 16 mounted on the central pipe 2. Next, by gripping the crane, the grill 1 hooks onto the fungus 18, while the supporting disk 21 is used as a support for gripping the crane. The grill 1 is removed from the slot of the transport cover and reloaded into the housing of the pencil case. The capture of the crane-manipulator disengages from the fungus 18 of the capture 16, which is then removed from the central pipe 2 by an electromechanical manipulator, and the ampoule 15 previously removed from it is installed in the central pipe 2.

Claims (3)

1. The lattice of the spent nuclear fuel storage case of the RBMK-1000 reactor, including a central tube attached to the base, vertical posts and cells for accommodating ampoules with fuel rods bundles, made in several coaxial tiers, a base in which holes are made coaxial with the cell symmetry axes, characterized in that the inner diameter of the central pipe is made equal to the inner diameter of the cells, a hole is made in the base along the axis of the central pipe, and the grill is equipped with a device for its engagement after being removed I ampoule of a central tube. 2. The grill according to claim 1, characterized in that in the upper part of the central pipe, grooves are made according to the type of bayonet connection. 3. The lattice according to claim 1, characterized in that its cells are made with the possibility of installing ampoules with an increased diameter in them.

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