RU2620132C1 - Canister for spent fuel assemblies - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: invention relates to the nuclear power industry, in particular to the devices for handling with spent nuclear fuel, and more specifically to the canisters with loaded spent fuel assemblies (SFAs) or their parts. In the canister for damaged SFA comprising thin-wall housing, a bottom and a cover, the cover has two locks. The locks are installed in the cover groove and interacts with groove in the housing. The locks are pressed by compression springs. Sealing gaskets are installed between the cover and the housing. Slots are made in locks, through the locks limiting screws installed in the cover pass. Against screws in cover plugs are tightly installed.

EFFECT: invention ensures location, storage and transportation in the canister of the damaged and destructed SFAs.

3 cl, 4 dwg

Description

The invention relates to nuclear energy, in particular to devices for the management of spent nuclear fuel, and more particularly to pencil cases that house spent fuel assemblies (SFA) or parts thereof.

The case for spent fuel assemblies is designed to contain defective SFAs discharged from the storage of nuclear and radiation hazardous facilities and spills of active elements of the destroyed SFAs for subsequent shipment for processing in existing transport packaging systems.

A well-known container for transporting spent fuel assemblies of nuclear reactors, comprising a housing closed on top with a sealing cap, and a removable part inserted into the cavity of the housing, in the openings of the diaphragms of which the SFA covers are remotely placed. Covers of various sizes are either mounted with their lower ends on the bottom of the container, or hung on the supporting collars in the holes of the board of the extraction part for the upper collars of the covers (see, for example, Russian patent No. 2120675, G21F 5/008, filed April 24, 1996, published October 20, 1996. 1998).

The main disadvantages of such a device include the following:

- the inability to place, store and transport defective and destroyed SFAs;

- does not have the ability to quickly lock the device cover;

- there is no possibility of reprocessing spent nuclear fuel (SNF) together with a canister upon receipt of a fuel regeneration (RT) plant.

A known case for spent nuclear fuel of a water-cooled power reactor VVER-1000, comprising a housing with dividing walls installed inside it, forming cells, a lid with a fungus equipped with a valve device and a device for engaging the lid with the housing, vertical struts installed inside the housing and a central pipe . The vertical posts and the central pipe are connected by dividing partitions with the formation of four cells between them. Vertical racks are placed around the perimeter of the case so that the angles between the dividing walls in two opposite cells are equal to the angle between adjacent faces of the SFA. In two other opposite cells, the angles between the dividing walls are equal to the angle between the non-adjacent faces of the SFA. In these two cells, the separation partitions are connected by vertical plates with the formation of half a hexagonal section exceeding the hexagonal section of a non-serial SFA (see, for example, Russian patent No. 2510087, G21F 5/00, filed September 5, 2012, published September 5, 2012).

The main disadvantages of such a device include the following:

- the inability to place, store and transport defective and destroyed SFAs;

- does not have the ability to quickly lock the device cover;

- there is no possibility of reprocessing spent fuel together with a canister upon receipt at the RT plant.

Known ampoule for spent fuel assembly, which houses the bundles of fuel rods of spent fuel assembly of the RBMK-1000 reactor, for subsequent placement and transportation in a transport packaging in a dry storage for reloading in sealed metal canisters and long-term storage. The ampoule contains a cylindrical body with a bottom and a cover. Cylindrical blind holes are made in the bottom of the body and the ampoule cover, in which compression springs are installed, one ends of which are attached to the end surfaces of the cylindrical blind holes, and support plates are installed on the other ends. Between the springs with support plates is a bunch of spent fuel elements (see, for example, Russian patent No. 2505871, G21F 5/00, filed December 4, 2012, published January 27, 2014).

The main disadvantages of such a device include the following:

- the inability to place, store and transport defective and destroyed SFAs;

- does not have the ability to quickly lock the device cover;

- there is no possibility of reprocessing spent fuel together with a canister upon receipt at the RT plant.

Known capsule (pencil case) for collecting spillage, consisting of a container for collecting spillage of solid radioactive waste, the body of which is made in the form of a hollow cylinder with a sealed bottom and suction and discharge pipes located in the upper part of the body, a locking device and a locking filter for delaying and accumulating particles spillage. In this case, the locking filter is made of highly porous corrosion-resistant material and is installed inside the housing in front of the outlet pipe, and the suction pipe is connected to the suction channel, made in the form of a pipe, with a length corresponding to the length of the filter (see, for example, Russian patent No. 2430436, G21F 5 / 00, announced on 05/04/2010, published on 09/27/2011).

The disadvantage of this design is the inability to place, store and transport defective and destroyed SFAs.

The technical result of the invention consists in the possibility of placement, storage and transportation of defective and destroyed SFAs in a canister.

The specified technical result consists in the fact that in the case for accommodating defective spent fuel assemblies containing a thin-walled body, a bottom and a cover, the cover is provided with two locks installed in the groove of the cover and interacting with the groove in the body, the locks are pressed by compression springs between the cover and the body sealing gaskets are installed, grooves are made in the locks, through which the restrictive screws installed in the cover are passed, and on the contrary, plugs are hermetically sealed in the roof.

On a thin-walled case of the pencil case, risk is applied, along which the inactive part of the spent fuel assembly is separated.

The case is made thin-walled, allowing to process waste fuel assemblies together with a pencil case.

The invention is illustrated by drawings, which depict:

In FIG. 1 - pencil case in general form;

In FIG. 2 - the principle of operation of locks;

In FIG. 3 - readjustment of an empty pencil case for transportation and leak testing;

In FIG. 4 - installation of a pencil case in a loading post.

A case for placing a defective spent fuel (hereinafter referred to as a case) consists of a housing 1 consisting of pipes 2 and 3, a bottom 4, a ring 5 and a cover 6. The cover 6 is inserted into the pipe 3 and fixed with two locks 7 in the groove 8 of this pipe due to the action of compressed springs 9. Thus, the cover 6 is made quick-release with the fixation of the closed position, providing sealing of the internal cavity of the canister.

On the case 1 of the canister, risk 10 is applied, according to which, according to the technology adopted at the RT plant, the idle end of the SFA located in the canister will be separated from its active zone.

To prevent the locks 7 from falling out of the cover 6, two screws 12 are screwed into the cover 6 through the grooves 11 of the locks 7. To remove the cover 6 from the case, unscrew the plugs 13 and press the locks 7 towards the center of the cover 6 using a special device 15 in the form of a wedge and then extract it.

The tightness of the case is ensured by rubber gaskets 16, 17 and is checked at the manufacturing stage by supplying compressed air to the case with immersion in a container of water. To supply compressed air, one of the plugs 13 is replaced with a nipple 18, and for transporting an empty pencil case, the standard head 19 is replaced with an eye bolt 20.

The material of the pencil case is stainless steel.

Pencil work is performed as follows:

A case without a cover 6 is installed in the SFA loading station 21 (see Fig. 4). Defective SFAs or spills of elements of the active part of the destroyed SFAs are loaded into the pencil case. Next, the lid 6 is locked and the canister is transported similarly to the transportation of intact SFAs.

Due to the design of the cover 6 using locks 7 and springs 9, it becomes possible to quickly lock a defective spent fuel located in a pencil case.

Thin-walled housing 1 allows you to process the SFA together with a pencil case.

The gripping part of the canister provides work with the existing transport and technological equipment at the RT plant and existing base containers.

Due to the fact that this case is not negotiable and its body is made of a thin-walled pipe, it fits into the existing transport and technological scheme for transporting spent nuclear fuel and cutting at the RT plant.

The case with internal SFAs or spills of elements of the active part of the SFAs has negative buoyancy, which ensures the fulfillment of the requirements of the technological process at the RT plant.

This invention makes possible the placement, storage and transportation of defective and destroyed SFAs.

Claims (3)

1. A case for accommodating defective spent fuel assemblies, comprising a housing, a bottom and a cover, characterized in that the cover is provided with two locks installed in the groove of the cover and interacting with a groove in the body, the locks are pressed by compression springs, sealing gaskets are installed between the cover and the body, grooves are made in the locks, through which the restrictive screws installed in the cover are passed, and plugs are hermetically sealed in front of the screws in the cover. 2. Pencil case according to claim 1, characterized in that a risk is applied to the thin-walled case of the pencil case, which separates the inactive part of the spent fuel assembly. 3. Pencil case according to claim 1, characterized in that the housing is thin-walled, allowing to process spent fuel assemblies together with the pencil case.

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