RU2403638C1 - Cartridge for spent fuel assembly - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to cartridge, where defect bundle of fuel elements (FEB) of spent fuel assembly (SFA) is placed for temporary storage in spent fuel pond and further dry storage. Concept of the invention is as follows: cartridge for spent fuel assembly comprises cylindrical body with bottom and cover. Defect bundle of fuel elements is placed in body. Height of cartridge body makes it possible for the grip to have access to power grid of fuel elements bundle. Spring is installed in cartridge cover. Spring provides for fixation of fuel elements with various length in cartirdge. Labyrinth channels are arranged in bottom and cover, making it possible to fill and drain inner cavity water as cartridge is installed into spent fuel pond for temporary storage. Labyrinth channels prevent spillage of fuel particles from cartridge and make it possible to dry fuel elements bundle. Autonomous system of cartridge cover lock opening is provided on cartridge body neck.

EFFECT: invention makes it possible to install defect fuel elements bundle in cartridge, to temporarily place cartridge into pond, to conduct drying after withdrawal from spent fuel pond, and to provide for monitoring of bundles in process of long-term storage.

4 cl, 2 dwg

Description

This invention relates to nuclear energy, in particular to an ampoule into which a bundle of fuel rods (PT) of an spent fuel assembly (SFA) of an RBMK-1000 reactor is loaded, which, for some reason, could not be placed in a standard ampoule.

The fuel assembly of the RBMK-1000 reactor consists of two bundles of fuel elements interconnected by a central rod and a suspension. The fuel elements (fuel rods) made in the form of rods are mounted on the frame of the PT with the help of power and several spacing grids. Each PT has a hemisphere tip at one end. Suspension is attached to the central rod passing through the tip of the upper PT.

It is known that prior to dry storage, spent fuel assemblies (SFAs) are removed from the holding pool, where they were stored in water, and divided into two bundles of fuel elements and part of the supporting rod. In this case, the bundles of fuel rods (PT) are to be installed in ampoules. The separation of the SFA into bundles of fuel rods is performed in the protective chamber of the cutting department at the nuclear power plant. Ampoules with bundles of fuel rods are installed in a case, which is loaded into a storage packaging kit (UKH) or in a transport container. In a stationary storage ampoules with bundles of fuel rods are placed in metal sealed canisters. In order to exclude the corrosive effect of water on the pencil case and fuel rods, which remains on the PT after disassembling the SFA and loading the PT into the ampoules, the ampoule is dried. A feature of this method of storing the spent fuel assembly in an ampoule is that ampoule storage provides localization of particles of the fuel composition and structural elements of fuel rod bundles in the event of their destruction during transportation and storage.

To increase the capacity of the transport container, the cover is performed with a minimum step with holes of minimum diameter, capable of accommodating an ampoule of the minimum allowable diameter. But, in the process of cutting the SFA, there may be situations when the PT cannot be installed in the ampoule of the minimum diameter. Such situations can occur with the fall of the PT, the destruction of the spacing grids, the initial increased curvature of the PT and a number of other events. In this case, a defective PT, which cannot be removed from the hot chamber using standard technology, must be placed in a special ampoule of a larger diameter and returned to the holding pool until the hot chamber is reconfigured to cut the defective SFA.

The closest in technical essence to the claimed invention is an ampoule (patent RU No. 2353010, G21F 5/008) containing a cylindrical body with a bottom, in which a bundle of fuel rods of the spent fuel assembly is placed, and a cover fixed in the upper part of the body with a locking device in the form of a spring split ring, the case of which is made high, allowing access to the power grid of the fuel rod bundle, mounted on the bottom of the ampoule with the support of the frame tube, a spring is installed in the ampoule cover, providing yuschaya fixation in ampoule fuel bundles of different length, and a constructive gap between the lid and body of the ampoule is designed as a labyrinth seal preventing the fuel from flowing out the particles from the vial and providing the possibility of drying fuel bundle loaded in the vial.

The disadvantage of this ampoule in this case is that it is impossible to install a defective bundle of fuel rods in it.

An object of the invention is to develop an ampoule design for storing spent fuel bundles, which makes it possible to place bundles of spent fuel assemblies for RBMK-1000 reactors, which for some reason cannot be loaded into standard small-diameter ampoules, and temporarily place it in the holding pool.

Due to the fact that the ampoule is temporarily placed in the holding pool, and the ampoule lid does not close it hermetically, it is advisable to make labyrinth channels in the lid and bottom of the ampoule, which can guarantee filling and emptying the internal cavity of the ampoule from water, but excluding the precipitation of fuel particles from the ampoule.

It is advisable to open and close the ampoule with the help of a manipulator installed in the protective chamber of the cutting compartment at the NPP.

It is advisable to make the labyrinth channels in the lid and bottom of the ampoule body in a form that prevents the fuel particles from spilling out of the ampoule and at the same time provides drainage of water and the possibility of drying the PT loaded into the ampoule, for example, due to its own residual heat.

When using the invention, the following technical results may occur, in particular:

- providing the ability to install in the ampoule of defective PT;

- guaranteed filling of the ampoule with water and discharge of water from the ampoule before drying when the ampoule is put into dry storage;

- opening the lock of the ampoule locking device with an autonomous autopsy system using the hot chamber manipulator when loading the PT into the ampoule in the SFA cutting compartment;

- monitoring of fuel bundles during storage.

The technical result is achieved by the fact that the ampoule body has such a length that the power grate rises above it to a height sufficient for guaranteed capture of the PT of the minimum length, and the diameter of the ampoule allows the installation of a defective PT.

Labyrinth channels in the lid and bottom of the ampoule body prevent fuel particles from spilling out of the ampoule, ensure that the ampoule is filled with water when it is temporarily stored in the holding pool, as well as the subsequent drainage of water and the possibility of drying.

An autonomous ampoule opening system allows you to work with it, while the cutting compartment is configured to work with defective SFAs.

The invention is illustrated by the drawings shown in figures 1-4:

figure 1 - General view of the ampoule to accommodate the bundle of fuel rods;

figure 2 - Autonomous system of opening the ampoule (fragment B of figure 1);

figure 3 - Device for draining water (fragment In figure 1);

figure 4 - Device for the release of air (fragment a of figure 1).

Patented ampoule 1 (Fig. 1) contains a housing 2 made in the form of a pipe with a bottom 3, in which the spent fuel rods are placed, a cover 4 included in the neck 5 (Fig. 2) of the ampoule housing 2, and a damper 6 made coaxially with case 2 ampoules on the outer end of the bottom 3 of the ampoule body.

In the neck 5 (figure 2) of the housing 2 of the ampoule 1, a groove 7 is made, in which a control sleeve 8 is installed, which opens the ampoule when removing the cover 4 from the housing 2 of the ampoule 1 (figure 3).

In the bottom 9 (Fig. 4) of the cover 4, annular grooves 10 and grooves 11 (for example, four) are made, which allow air to escape through the openings 12 when the ampoule 1 is lowered into the water of the holding pool. In this case, the plate 13 overlaps the grooves 11, preventing the free exit of spent nuclear fuel (SNF) particles from the ampoule. The holes 12 and the grooves 11 are made with an offset along the arc relative to each other.

In the lower inner surface of the housing 2 (Fig. 3), a ring 14 is fixed (for example, by welding), in which a groove and grooves 15 are made (for example, in an amount of 18), and holes 16 (for example, in an amount of 16 are made in the body 2) ) In this case, a cavity 17 is formed in which SNF particles are retained when water is drained from the ampoule with the PT before it is returned to the cutting compartment for loading into the transport container.

In the initial state, the cover 4 is located in the housing 2 of the ampoule (figure 1).

When lifting the cover 4, that is, opening the ampoule 1, it is necessary to raise the sleeve 14 and rotate it with the help of a manipulator installed in the protective chamber of the cutting compartment at the nuclear power plant.

Before installing the ampoule with the PT in the container, water vapor is removed from the ampoule through the annular gap between the cover 4 (Fig. 2) and the ampoule body 2 and labyrinth channels made in the cap and bottom of the ampoule (Figs. 3 and 4).

Claims (4)

1. An ampoule for a spent fuel assembly comprising a cylindrical body with a bottom and a cover, the body of which is made high, which allows access to the power grid of the fuel rod bundle, a spring is installed in the ampoule cover to fix the fuel bundles of different lengths in the ampoule, characterized in that labyrinth channels are made on the bottom of the case and on the ampoule cover, which allow filling and emptying the internal cavity of the ampoule from water and preventing fuel particles from spilling out of the ampoule, and autonomously made on the neck of the ampoule body I'm opening the system ampoules. 2. The ampoule according to claim 1, characterized in that the autonomous system for opening the ampoule is made in the form of a sleeve coaxially located in the groove in the neck of the ampoule. 3. The ampoule according to claim 1, characterized in that the labyrinth channel in the ampoule cover is made in the form of two annular grooves connected by grooves, partially overlapped by a plate fixed on the inside of the cover, and holes through the cover. 4. The ampoule according to claim 1, characterized in that the labyrinth channels in the lower part of the ampoule body are formed by a groove and grooves fixed in a ring mounted on the bottom of the ampoule body and secured, for example, by welding and holes in the ampoule body.

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