RU2284063C1 - Refueling system - Google Patents

Abstract

FIELD: refueling reactors, primarily light-water ones, at nuclear power stations.

SUBSTANCE: proposed refueling system that has intermediate chamber accommodating conveyer with pockets and communicating through vertical channels with reactor and fuel compartments is characterized in that leak-tight reservoir is installed in its intermediate chamber. Conveyer with pockets designed to receive fuel assemblies and install them in vertical position is disposed inside leak-tight reservoir; number of conveyer pockets is not to be less than that of fuel assemblies to be handled within one refueling procedure. Leak-tight reservoir communicates with vertical channels through sealing devices such as valves. Leak-tight reservoir may be of circular shape.

EFFECT: reduced shutdown time of reactor for its refueling.

3 cl, 2 dwg

Description

The invention relates to the field of nuclear engineering and can be used to reload fuel assemblies of a nuclear reactor at nuclear power plants mainly with light-water reactors.

A secure lock device is known for use in a reactor reloading system for transporting fuel between a reactor compartment under a containment and a fuel enclosure located outside the containment. The lock device is a horizontal channel in the form of a pipe crossing the protective sheath in its lower part and located under a layer of water. From the side of the reactor compartment and from the side of the fuel casing, the channel is equipped with means for sealing it. To transport fuel assemblies along the channel, a trolley is used on which the fuel assemblies are located in a horizontal position. At the end sections of the gateway device - in the reactor compartment and the fuel casing, mechanisms are installed that rotate the cart with fuel to a vertical position for the capture and transfer of fuel by the mechanisms of the reactor compartment and the fuel casing, and the reverse action with the trolley. (UK patent No. 1499430 from 15.07.75)

The disadvantages of this design include:

Long overload time associated with the transportation of fuel assemblies by the piece.

Transporting fuel horizontally increases the likelihood of damage to fuel assembly components.

A known method of reloading nuclear fuel, which describes a system for reloading fuel assemblies, containing a sealed lock, which serves to communicate between the reactor compartment, located under the protective shell, and the fuel casing located outside the protective shell. An airtight lock crosses the protective shell in its lower part and is equipped with passage sealing mechanisms. The means of transporting the fuel assemblies through the airlock are the carts with containers into which the fuel assemblies are installed in an upright position. (US Patent No. 4158599 dated 09/20/77)

In this device, the disadvantages of the above analogue have been eliminated in that the assemblies are transported in an upright position in a container containing several overloaded assemblies.

The disadvantages of this device are:

The large overall dimensions of the airtight lock, due to the size of the container with assemblies passing through it, and, as a result, the complexity of the design of the sealing mechanisms of this lock.

The complication of the reloading process is due to the need to use special programs when loading assemblies into the container and unloading from it to direct the grips of the reloading machines of the reactor and fuel compartments to a given socket in the container.

The closest technical solution to the proposed invention is a system for reloading and preserving nuclear fuel and reflective elements, which includes: an intermediate box with a conveyor device, vertical channels, sealing means. The movement channel is designed to transfer fuel assemblies and reflective elements from the transport container of the reactor compartment to the protected chamber. The protected camera serves to connect the channel for movement with a shielded camera and contains devices for sealing the channel for movement, connection with the containers of the conveyor device, removing and reinstalling the lids from the containers. The conveyor device contains waterproof containers with lids designed for installation of fuel assemblies and reflective elements in them. The conveyor device moves containers with fuel assemblies installed in them and reflective elements between the moving channel and the transport channel. Through the transport channel, containers with fuel assemblies and reflective elements installed in them are moved to the storage area. (UK patent No. 2023911 from 06/12/79)

The disadvantages of this device include:

The use of this device in a system with "dry" overload, which involves the forced cooling of "spent" fuel assemblies with high residual heat.

The protected camera contains a large number of mechanisms that ensure the operation of the system, access to which is difficult, which leads to a decrease in reliability and maintainability.

The waterproof containers with lids used to house fuel assemblies complicate the design of the system and increase the overload time.

The technical result, to which the claimed invention is directed, consists in reducing the reactor shutdown time for overload, which significantly affects the increase in the installed capacity factor of the reactor.

To achieve the specified technical result, in the system of reloading fuel assemblies between the reactor compartment and the fuel compartment, containing an intermediate chamber with a conveyor with sockets located in it, connected by vertical channels to the reactor compartment and the fuel compartment, a sealed container is installed in the intermediate chamber. A conveyor with sockets designed to install fuel assemblies in them in an upright position is placed inside a sealed container, and the number of conveyor sockets is made not less than the number of fuel assemblies overloaded for one overload. The sealed container is connected to the vertical channels through sealing devices, such as valves. The sealed container may be made annular.

Placing the conveyor in an airtight container allows loading “fresh” fuel assemblies in the amount necessary for refueling, when the reactor is operating, just before the reactor is stopped for refueling, and also use it as an intermediate storage to reduce the residual heat emission of the “spent” fuel assemblies after the end of the process reactor overload and start-up. Sealing devices allow overloading of fuel assemblies separately between the reactor compartment and the sealed tank or between the sealed tank and the fuel compartment. Thus, in the process of overloading, one of the channels is opened connecting the sealed chamber with the reactor compartment and the fuel compartment, therefore, in any case, a protective barrier is maintained between the reactor compartment and the fuel compartment. Therefore, it can be argued that the reactor shutdown time for overload is reduced to ensure safety requirements for the presence of a protective barrier.

The shape of the sealed container can be selected taking into account the achievement of the minimum size of the opening in the protective shell of the reactor compartment, namely, the annular shape.

The invention is illustrated by drawings, where:

Figure 1 schematically shows a longitudinal section of an intermediate chamber of an overload system of fuel assemblies.

Figure 2 schematically shows a top view of a sealed container with a conveyor.

The fuel assembly reloading system includes an intermediate chamber 3, designed to transfer fuel assemblies 9 between the reactor compartment 2 and the fuel compartment 4. For overloading, the intermediate chamber 3 is connected to the reactor compartment 2 and the fuel compartment 4 by vertical channels 5. Inside the intermediate chamber 3 is installed a sealed container 1 containing a chain conveyor 7, equipped with trolleys with vertical sockets 8, designed to install fuel assemblies in them 9. Moving the transporter rtera 7 performs drive 10. For connecting the hermetic vessel 1 with channels 5 are sealing device 6.

The operation of the system of reloading fuel assemblies is as follows.

Before the reactor is reloaded, the “fresh” fuel assemblies are loaded from the storage (not shown) in the fuel compartment 4 into the slots 8 of the conveyor 7 in the quantity necessary for reloading. For this, the sealing devices 6 of the channel 5 are opened, connecting the sealed container 1 with the fuel compartment 4. An empty socket 8 of the conveyor 7 is installed under the channel 5 of the fuel compartment 4. A “fresh” fuel assembly 9 is reloaded by a reloading machine (not shown) of the fuel compartment 4 into the socket 8 conveyor 7. The above operations of installing "fresh" fuel assemblies 9 in slots 8 of the conveyor 7 are repeated until the number of "fresh" fuel assemblies 9 necessary for a given overload is reached.

After the loading process of the "fresh" fuel assemblies 9 is completed, the sealing devices 6 of the channel 5 of the fuel compartment 4 are closed. In the process of filling the sockets 8 of the conveyor 7 with the "fresh" fuel assemblies 9, the reactor can be shut down and prepared for overload. After preparing the reactor for overload, the valve 6 of the channel 5 of the reactor compartment 2 opens.

Under the opening of the channel 5 of the reactor compartment 2, the nearest free socket 8 of the conveyor 7 is supplied for installing the "spent" fuel assembly 9 from the reactor into it. The "spent" fuel assembly 9 from the reactor is delivered by a reloading machine (not shown) of the reactor compartment 2 to the empty slot 8 of the conveyor 7. Then, by the conveyor 7, a slot 8 of the conveyor 7 containing the "fresh" fuel assembly 9 is supplied under the opening of the channel 5 of the reactor compartment 2. " Fresh "fuel assembly 9 by the reloading machine of the reactor compartment 2 is installed in the reactor in place of the unloaded" spent "fuel assembly 9. The above operation is repeated until all" spent "fuel assemblies 9 are completely replaced discharged from the reactor to “fresh” fuel assemblies 9 contained in slots 8 of the conveyor 7.

After completion of the process of replacing the fuel assemblies in the reactor, the shutter 6 of the channel 5 in the reactor compartment 2 is closed. The "spent" fuel assemblies 9 located in the sockets 8 of the conveyor 7 are ready for further discharge to the fuel compartment 4. The sealed container 1 can be used as an intermediate storage of the "spent" fuel assemblies contained therein 9 to reduce residual heat. The heat generated by the fuel assemblies 9 stored in the sealed container 1 can be used for domestic purposes using a forced cooling system (not shown). Further work with the fuel assemblies 9 located in the sealed container 1 does not affect the work associated with the preparation of the reactor for start-up, and the start-up of the reactor.

The application of the proposed refueling system allows to increase the utilization factor of the installed reactor power by reducing the reactor shutdown time for refueling, while increasing the safety of the refueling system by maintaining a tight barrier between the reactor compartment and the fuel compartment.

Claims (3)

1. The system of reloading fuel assemblies between the reactor compartment and the fuel compartment, comprising an intermediate chamber with a conveyor with sockets located therein, provided with vertical channels connecting it to the reactor compartment and the fuel compartment, characterized in that the conveyor is enclosed in a sealed container installed in the intermediate chamber and connected to vertical channels through sealing devices, and the number of conveyor slots is not less than the number of fuel assemblies required for I'm single overload. 2. The fuel assembly overload system according to claim 1, characterized in that a valve is used as a sealing device. 3. The system of reloading fuel assemblies according to claim 1 or 2, characterized in that the sealed container is made annular.

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