JPH0823597B2 - Fast breeder reactor fuel handling equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel handling facility for a fast breeder reactor, and in particular, allows fuel to be taken out from the reactor vessel even during the operation of the reactor to enable flexible handling of the fuel. Related to the fuel handling equipment.

[Conventional technology]

The fuel handling facilities of conventional fast breeder reactors are shown in Figs.
As shown in the drawing, a concentric fuel storage rack 3 arranged around a reactor core 2 in a reactor vessel 1, a direct drive type fuel exchanger 5 mounted on a rotating plug 4, an in-reactor relay rack.
10, a fuel inlet / outlet 6, an outside-reactor relay tank 7, a fuel cleaning tank 8, a new fuel storage tank 9, an in-cell crane 11, and the like.

The rotary plug 4 consists of a combination of a large rotary plug 4L and a small rotary plug 4S, and the rotation of both plugs moves the fuel exchanger 5 between the core 2, the fuel storage rack 3 and the in-react relay rack 10, and all It is possible to handle fuel assemblies. If the in-reactor relay rack 10 is at the outermost peripheral position of the fuel storage rack 3, the size of the large rotation plug 4L is determined by the size of the fuel storage rack 3.

The direct-acting type fuel exchanger 5 has a structure capable of expanding and contracting in the vertical direction, and has a grip portion at its tip for gripping and releasing the fuel assembly. The fuel inlet / outlet machine 6 is a facility for transferring a fuel assembly between the in-reactor relay rack 10 and the out-reactor relay tank 7, and has a ramp 14 for transferring a fuel bucket 12 containing the fuel assembly. There is a relatively large space below the ramp 14 in the reactor vessel 1.

In FIG. 12, reference numeral 15 is a primary main pump, 16 is an intermediate heat exchanger, and 17 is a cold trap.
5 shows a fast breeder reactor with four intermediate heat exchangers 16 each. The portion where the cold trap 17 is located also has a relatively large space.

The fuel exchange by the fuel handling facility of the fast breeder reactor is carried out while the reactor is stopped, and the spent fuel assembly of the core 2 is exchanged with the new fuel assembly. In addition to the fuel assembly, the core 2 has core constituent elements such as control rods and shields, which will be collectively referred to as a fuel assembly hereinafter. The spent fuel assemblies of the core 2 are transferred to the fuel storage rack 3 by the refueling machine 5, and for a predetermined period of time, for example, 1 to remove the decay heat.
Stored during the operating cycle. The spent fuel assemblies from which the decay heat has been removed are used in the fuel exchanger 5 during the subsequent reactor shutdown.
As a result, the fuel is transferred from the fuel storage rack 3 to the fuel bucket 12 of the in-core relay rack 10. The spent fuel assemblies transferred to the fuel bucket 12 are transferred to the outside-reactor relay tank 7 by the fuel inlet / outlet machine 6, and further, the fuel cleaning tank 8 is transferred by the in-cell crane 11.
To be washed. The washed spent fuel assembly is carried from the fuel washing tank 8 to the fuel storage water pool by the in-cell crane 11.

On the other hand, the new fuel assembly is transferred from the new fuel storage tank 9 to the core 2 by the reverse route described above. That is, the new fuel assembly is transferred from the new fuel storage tank 9 to the outside-reactor relay tank 7 by the in-cell crane 11, and is further transported to the in-reactor relay rack 10 via the fuel inlet / outlet unit 6. After that, the new fuel assembly is transferred from the in-core relay rack 10 to the core 2 by the fuel exchanger 5. The transfer of this new fuel assembly from the outside of the reactor to the core 2 is also performed during the reactor shutdown.

Figure 13 shows an example of a fuel exchange schedule using the above fuel handling equipment. After operating the reactor for one year, the reactor will be shut down and about 200 fuels will be intensively replaced during the maintenance period of about 2 months. That is, about 200 spent fuel assemblies taken out from the core are temporarily stored in the fuel storage rack 3 and stored for the next one cycle of reactor operation in order to remove the decay heat. On the other hand, about 200 spent fuel assemblies that had been stored in the fuel storage rack 3 and had decay heat removed during one cycle of reactor operation were taken out of the reactor vessel 1 and washed with steam etc. It Further, about 200 new fuel assemblies are loaded into the core from outside the reactor via the relay rack 10 in the reactor. Therefore, it is necessary to handle the fuel including the cleaning of the spent fuel within a period of about 2 months, and the process becomes considerably strict. As a countermeasure against this, an extra-reactor fuel storage tank is provided outside the reactor vessel 1 using sodium as a coolant, and fuel may be transferred between the fuel storage tank and the reactor vessel during refueling. Taking out the spent fuel assembly from the out-of-core fuel storage tank using sodium,
Just wash it. However, the outside-reactor storage tank needs to be provided with a rotating mechanism, a fuel handling device, a purification system facility, etc. as facilities, and it is not preferable to install it from the viewpoint of rationalization.

The fuel exchanger includes an arm type in addition to a direct drive type, but an arm type fuel exchanger is disclosed in, for example, JP-A-59-5996 and JP-A-53-74696, and JP-A-48-46792 and Japanese Patent Application Laid-Open No. 63-150693 discloses a related fuel exchanger as Japanese Patent Application Laid-Open No. 55-101005. Further, there is JP-A-54-102496 as a shaft seal device of a fuel exchanger, and JP-A-60-100092 as an example of a fuel bucket.

[Problems to be Solved by the Invention]

From the viewpoint of rationalization, the above-mentioned conventional fuel handling facility does not have a sodium fuel storage tank outside the reactor, and therefore the fuel cannot be exchanged during the reactor operation when the rotating plug remains stopped. It was necessary to replace the spent fuel in the core with new fuel during a short period during the shutdown, and since the spent fuel was continuously taken out, transferred, washed, etc., the process became extremely strict. Therefore, particularly when a problem occurs due to sodium dripping or adhesion, it takes time for the processing for that, and it is not possible to secure a sufficient time margin for this.

Further, the size of the reactor vessel depends on the size of the rotating plug, and the size of the rotating plug depends on the moving range of the fuel exchanger mounted therein. In the conventional fuel handling facility, since the fuel storage racks are concentrically provided around the core, the moving range of the refueling machine is widened, and therefore the rotating plug and the reactor vessel are also sized accordingly.

An object of the present invention is to provide a fuel handling facility for a fast breeder reactor, which enables flexible handling of fuel by enabling fuel to be taken out of the reactor vessel from inside the reactor vessel even during operation of the reactor. It is to be.

Another object of the present invention is to provide a fast breeder reactor fuel handling facility in which the size of the reactor vessel can be reduced by reducing the diameter of the rotating plug.

[Means for solving the problem]

The above-mentioned object is provided with a connecting portion for varying a distance between a center of a gripping portion for gripping and releasing a fuel assembly in a nuclear reactor vessel and a center of a drive shaft penetrating a rotary plug, and the drive shaft is an axis. A refueling machine that is configured to be rotatable around a center and is mounted on a rotating plug, and a drive shaft of the refueling machine when the rotating plug is in a reference stop position, as a center,
When a circle is drawn with a maximum distance between the center of the grip portion and the center of the drive shaft as a radius, a first fuel storage rack for storing fuel assemblies, which is arranged within the circle except the core, and the circle. An in-reactor relay rack disposed inside the reactor vessel, and the inside of the reactor vessel is opposed to the refueling machine side when the rotary plug is in the reference stop position by a vertical plane including the core center axis. Achieved by the fuel handling facility of the fast breeder reactor, characterized in that when divided into two on the fuel exchanger side, all parts of the first fuel storage rack and in-reactor relay rack are arranged on the fuel exchanger side. To be done.

Preferably, the second fuel storage rack is arranged at a position symmetrical to the center of the core with respect to the first fuel storage rack.

Further, preferably, the maximum value of the distance defined by the connecting portion between the center of the grip portion and the center of the drive shaft is made equal to the radial length of the core component including the shield.

The above-mentioned purpose is also to provide a direct drive type fuel exchanger mounted on the rotary plug, and a distance between the center of the gripping portion for gripping and releasing the fuel assembly in the reactor vessel and the center of the drive shaft passing through the fixed plug. A fuel handling machine that is equipped with a fixed plug and that is configured to be rotatable about an axis of the drive shaft, and the gripping portion around the drive shaft of the fuel handling machine. When a circle is drawn with the maximum distance between the center of the cylinder and the center of the drive shaft as a radius, a fuel storage rack for storing fuel assemblies, which is arranged inside the circle except the core, and a furnace arranged inside the circle. An internal relay rack, and when the interior of the reactor vessel is divided into two parts by the vertical plane including the core center axis into the fuel handling machine side and the anti-fuel handling machine side, the fuel storage rack and the reactor All parts of the internal relay rack handle the fuel It is accomplished by a fast breeder reactor fuel handling equipment, characterized in that it is arranged on the side.

[Action]

In the present invention configured as described above, the first fuel storage rack and the in-reactor relay rack provided for fuel assembly storage are the fuel when the rotating plug is in the reference stop position in the reactor vessel. Place it on the half of the exchange side. That is, the first fuel storage rack and the in-core relay rack are not arranged in a donut shape around the core and concentric with the core as in the conventional case, but rather on one side of the core, that is, at the reference stop position. It is arranged so that it is offset to the exchange side. Moreover, at this time, the first fuel storage rack and the in-reactor relay rack are circles whose center is the drive shaft position when the rotary plug is at the reference stop position and whose radius is equal to the maximum distance between the center of the grip portion and the center of the drive shaft. It is located inside. As a result, with the rotating plug stopped at the reference stop position,
By rotating the refueling machine main body around the drive shaft and changing the distance between the center of the grip and the center of the drive shaft at the connecting part, the grip is raised and lowered to grip and release the fuel assembly. All parts of the first fuel storage rack and the in-core relay rack can be accessed and handled without hindrance.

Further, in the present invention, the fuel storage rack and the in-react relay rack provided for fuel assembly storage are arranged in the half of the reactor vessel side in the reactor vessel. That is, these fuel storage racks and in-react relay racks are not arranged in a donut shape that is concentric with the core around the core as in the conventional case, but are biased toward one side of the core, that is, the fuel handling machine side. Will be placed. Moreover, at this time, the fuel storage rack and the in-reactor relay rack are arranged in a circle whose center is equal to the drive shaft position of the fuel handling machine and whose radius is equal to the maximum distance between the center of the grip portion and the center of the drive shaft. As a result, with the rotating plug stopped, the main body of the fuel handling machine is rotated around the drive shaft, and the distance between the center of the gripping part and the center of the drive shaft is changed at the connecting part, while the gripping part is moved up and down to move the fuel. By gripping and releasing the assembly, all the parts of the fuel storage rack and the in-react relay rack can be accessed and handled without being disturbed by the core.

Therefore, in other words, unlike the conventional case where no refueling work could be performed during the reactor operation in which the rotary plug remained stopped, the first fuel storage rack (or the fuel storage rack) remained in operation even during the reactor operation. Since the stored spent fuel assemblies can be carried out to the outside of the reactor via the relay rack in the reactor for cleaning, the fuel exchange work time during the reactor shutdown can be shortened accordingly.

In addition, when refueling while the reactor is stopped, the fuel storage racks that were concentrically provided around the core, which previously required positioning of the refueling machine with a rotating plug, were abolished.
Positioning of the fuel exchanger by the rotary plug may be performed up to the fuel assembly at the outermost periphery of the core or in the vicinity thereof, and the diameter of the rotary plug can be reduced. On the other hand, in the facility of the present invention, the fuel storage rack can be installed in the lower part of the ramp or the cold trap part of the fuel inlet / outlet machine which has a relatively large space.
Therefore, the size of the reactor vessel can be made smaller than before.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 to 3, the fast breeder reactor is a reactor vessel 20.
It has a core 21 located inside, and four primary main pumps 22 and intermediate heat exchangers 23, and two cold traps 24 are arranged around the core 21. Also, above the core 21,
A reactor upper part mechanism 25 including a control rod drive mechanism for controlling the output of the core 21 is arranged.

Fuel handling equipment for such fast breeder reactors is
A fuel storage rack 30a for reactor operation and shutdown periods, which is disposed adjacent to 21, a fuel storage rack 30b for reactor shutdown periods, an intra-reactor relay rack 31, and a reactor vessel 20.
Rotating plug 32 that constitutes the top shield of the
A fuel exchange machine 33 mounted on the fuel tank, a ramp 34 leading to the fuel relay rack 31, and a fuel inlet / outlet port 36 for inserting / removing the fuel assembly 35 into / from the reactor vessel 20, and a fuel inlet / outlet port 36. An external relay tank 37 for temporarily storing the assembly is provided, and a fuel cleaning tank, a new fuel storage tank, an in-cell crane and the like (not shown) are further arranged in the chamber where the fuel inlet / outlet device 36 is located. In addition, the spent fuel assembly 35
Are placed in a fuel bucket 38 and transported in the ramp 34.

The rotary plug 32 is composed of a combination of a large rotary plug 32L and a small rotary plug 32S that are eccentric to each other.
Also, the refueling machine 33 is mounted on the small rotation plug 32S.

The fuel exchanger 33 has a small rotation plug 32S as described later.
Drive shaft 40 and hold-down shaft 41 penetrating through, a grip portion 42 for gripping and releasing the fuel assembly, and a grip shaft 42
A drive shaft 40 and a hold-down shaft 41 are configured so as to be rotatable about their axes. That is, the refueling machine 33 has the function of rotating the refueling machine main body added to the function of the conventional arm-type refueling machine. As shown in FIG. 2, the fuel exchanger 33 is positioned so that the shaft center of the drive shaft 40 is located on the outermost periphery of the core 21 at one rotation position of the large and small rotary plugs 32L and 32S. The large and small rotary plugs 32L and 32S are held in a stopped state at this position during the reactor operation. Therefore, in this specification, the positions of the rotary plugs 32L and 32S are referred to as reference positions or reference stop positions.

The fuel storage rack 30a is arranged as follows. Refueling machine 3 when the small rotary plug 32S is in the reference stop position
When a circle is drawn with the radial movement stroke 1 (the maximum distance between the center of the gripping part 42 and the center of the drive shaft 40) of the gripping part 42 as the radius around the drive shaft 40 of 3 as a center, the fuel storage rack 30a
Are arranged so as to be located within this circle except for the core, and in particular, in the present embodiment, they are shaped so as to substantially coincide with the circle. Therefore, the fuel assemblies stored in the fuel storage rack 30a are within the range of the radial movement stroke 1 of the grip portion 42. The in-core relay rack 31 is also located within the range of the circle. For this reason, the fuel can be transferred between the fuel storage rack 30a and the in-reactor relay rack 31 by the fuel exchanger 5 both during the reactor operation and during the reactor shutdown.

The other fuel storage rack 30b is arranged symmetrically to the fuel storage rack 30a with respect to the core 21 in order to eliminate unevenness of heat flow in the reactor vessel 20. The fuel assembly in the fuel storage rack 30b can be handled by the refueling machine 5 while the reactor in which the rotary plug 32 can be rotated is stopped, that is, when the fuel is exchanged.

Also, the fuel storage racks 30a and 30b are both the same as the conventional ones.
A small amount of coolant is made to flow from the lower portion to cool the stored fuel assembly. The influence of the coolant flowing through the storage racks 30a and 30b on the core flow rate distribution is small and can be ignored.

Further, the core 21 has a total of about 1100 core components such as a core fuel assembly, a blanket fuel assembly, a control rod assembly, and a shield. Of these, the number of core fuel assemblies that can be replaced at one fuel exchange is the core fuel assembly. There are about 180 bodies including the body. Each of the fuel storage racks 30a and 30b has a total number of core components.
It is possible to store 1/2 or about 550 core components, and when refueling during reactor shutdown, about 180 spent fuel assemblies are transferred to the fuel storage rack 30a by the refueling machine 33,
During the operation of the reactor, these spent fuel assemblies are transferred from the fuel storage rack 30a through the core relay rack 31 to the reactor vessel 20.
It will be taken out and washed. In the following,
Core components such as a core fuel assembly, a blanket fuel assembly, a control rod assembly, and a shield are collectively referred to as a fuel assembly.

The fuel exchange procedure during the reactor operation using the above fuel handling equipment will be described below. In FIG. 1, it is assumed that the rotary plug 32 is in a stopped state at the reference position and the reactor power is controlled by the control rod drive mechanism of the core upper part mechanism 25. Here, it is assumed that the spent fuel assemblies have already been transferred from the core 21 to the fuel storage rack 30a by the fuel exchanger 33 in the fuel exchange during the previous nuclear reactor shutdown to remove the decay heat. The spent fuel assembly is cooled by the fuel storage rack 30a for a predetermined period during reactor operation to remove decay heat, and then the fuel is stored in the relay rack 31 from the fuel storage rack 30a by the grip 42 of the fuel exchanger 33. Transferred to bucket 38. The fuel bucket 38 is transferred to the outside-reactor relay tank 37 by the fuel inlet / outlet device 36 via the ramp 34, but outside the reactor relay tank 37.
The transfer procedure from the fuel tank to the fuel cleaning tank and the transfer procedure to the fuel storage water pool are the same as in the conventional method, and will be omitted.

On the other hand, the new fuel assembly is also transferred from the new fuel storage tank to the fuel bucket 38 in the external relay tank 37 in the same manner as before, and then the fuel is transferred in and out of each fuel bucket from the external relay tank 37 to the internal relay rack 31. Transferred by machine 36. Further, this new fuel assembly is taken out from the fuel bucket 38 in the in-core relay rack 31 by the fuel exchanger 33 and loaded into the fuel storage rack 30a. The operation of gripping, transferring, and releasing the fuel assembly between the in-reactor relay rack 31 and the fuel storage rack 30a is performed by the drive shaft of the fuel exchanger.
This is performed by the operations of 40, the hold-down shaft 41, and the grip portion 42. Positioning of the grip portion 42 of the fuel exchanger 33 to the upper part of the fuel assembly is performed by a combination of the tilting operation of the arm 42 in the radial direction of the fuel exchanger 33 and the rotating operation of the drive shaft 40. The operation of these refueling machines 33 will be described later in detail.

Next, when refueling while the reactor is shut down, large and small rotating plugs
The fuel storage rack 30a, the fuel storage rack 30b, the in-reactor relay rack 31, by the rotational operation of 32L and 32S, the gripping and releasing of the grip portion 42 of the fuel exchanger 33, the vertical movement, and the rotational operation of the drive shaft 40 of the fuel exchanger 33. And transferring the fuel assembly between two of the four regions of the furnace 21. Here, the transfer of the fuel assembly between the in-core relay rack 31 and the core 21 is the same as the conventional fuel exchange. Transfer of the fuel assembly between the in-reactor relay rack 31 and the fuel storage racks 30a, 30b, and between the fuel storage racks 30a, 30b and the core 21 is performed by the large and small rotary plugs 32L, 32S and the conventional fuel exchange function by the fuel exchanger 33. In addition, it is possible by the rotating operation of the drive shaft 40 of the fuel exchanger 33.

Fig. 4 shows an example of a fuel exchange schedule by the above fuel handling equipment. After operating the reactor for one year, the reactor is shut down and the core 21 is refueled during the maintenance period of about 2 months. That is, about 180 spent fuel assemblies taken out from the core are stored in the fuel storage rack 30a for one day and stored for one cycle of the next reactor operation in order to remove the decay heat. In addition, about 180 new fuel assemblies are loaded into the core from outside the reactor via the relay rack 31 in the reactor. On the other hand, in the next reactor operation one cycle period, about 180 spent fuel assemblies stored in the fuel storage rack 30a and having decay heat removed are taken out of the reactor vessel 20 and steam etc. Wash with. Therefore, it is not necessary to handle the spent fuel assembly including the cleaning during the maintenance period having a short period, and a considerable margin can be provided in the process. Therefore, even if troubles due to sodium dropping and adhesion occur, sufficient time can be secured for the treatment.

As described above, in the present embodiment, it is possible to take out the spent fuel assemblies in the fuel storage rack 30a to the outside of the reactor vessel 20 even during the operation of the reactor and wash them, and it is limited to the conventional reactor shutdown. The flexibility of refueling has been increased, and when refueling during maintenance during a reactor shutdown, it is possible to omit the conventional cleaning of the fuel assembly, which reduces the time required for refueling during maintenance during a reactor shutdown. Can be shortened.

Further, in the present embodiment, in the fuel exchange during the reactor shutdown, the fuel storage rack provided concentrically on the outer periphery of the core, which conventionally required the positioning of the fuel exchanger 33 by the rotary plug 32, was abolished. The refueling machine can be positioned by the fuel assembly at the outermost periphery of the core,
The diameter of the rotary plug 32 (large and small rotary plugs 32L, 32S) can be reduced accordingly. Further, the fuel storage racks 30a and 30b can be installed in the lower portion of the slope 34 of the fuel inlet / outlet device 36 or the portion where the cold trap 24 is located, which has a relatively large space in the past. Therefore, the size of the reactor vessel 20 can be made smaller than before.

Next, the detailed structure of the fuel exchanger 33 will be described with reference to FIGS. 5 and 6. The refueling machine 33 includes the drive shaft 40, the hold-down shaft 41, the arm 42, and the grip portion 43 as described above. The drive shaft 40 is suspended by two wires 44, and this wire is moved up and down by a drive device 46 located at the uppermost part of the exchange main body 45, so that the drive shaft 40 and thus the gripping portion 43 are also moved up and down. The drive device 46 includes a wire winding drum, a speed reducer,
It is composed of a motor and is a general-purpose type. The arm 42 is connected to the arm drive shaft 47, and the inclination θ of the arm 42 is changed by the operation of the arm drive shaft 47, and the distance l ′ between the grip portion 43 and the drive shaft 40 is changed within the range of the movement stroke 1 described above. The grip portion 43 has a claw, and opening and closing of the claw is performed by a speed reducer and a motor in a drive device 48 provided at the upper end of the drive shaft 40. The arm drive shaft 47 is also driven by a speed reducer and a motor inside the drive device 48. The hold-down shaft 41 is also moved up and down by a drive device 49 provided at the upper end in conjunction with the vertical movement of the drive shaft 40 described above. All of the above-described configurations for gripping, releasing, and moving up and down the fuel assembly are basically known as described in JP-A-59-5996, JP-A-53-74696, etc. , Detailed description is omitted.

A fuel exchanger hole door valve 50 and a fuel exchanger door valve 51 are installed on the upper end of the hold-down shaft 41, and a shaft sealing device 52 is provided on the fuel exchanger hole door valve 51. Fuel exchange hole door valve 50 and fuel exchange door valve 51
Are to form the boundary of the reactor vessel 20 and the boundary of the refueling machine 33 during the maintenance period,
Each shutter has a "0" ring and is driven by a motor via a ball screw and speed reducer. These structures are also known, and the shutters of the door valves 50 and 51 are open during the use of the fuel exchanger 33. In particular, the shaft seal device 52 of the refueling machine door valve 51 becomes the cover gas boundary of the reactor vessel when the refueling machine 33 is in use. In this shaft seal device 52, "0" ring, gasket, etc. are used as sealing material,
Moreover, the structure is such that fresh argon gas is blown out from the shaft sealing device 52 toward the inside of the furnace.

The feature of the fuel exchanger 33 is that the rotation function of the drive shaft 40 and the hold-down shaft 41 is added to the above-described arm type fuel exchanger as described above, and this point will be described below. The main body 45 of the exchanger is a bearing 53 provided on the door valve 51 of the fuel exchanger.
Supported by. Further, the exchange main body 45 is provided with a gear 54, and the gear 54 is installed on the fuel exchange door valve 51.
It is rotated by meshing with another gear 57 which is connected to 55 through a speed reducer 56. This causes the exchange body 45 to rotate. The rotational position of the exchange main body 45 at this time is detected by receiving a signal from a general purpose Celsin oscillator 58 provided on the central axis of the gear 57 in a receiver. These configurations are the same as the drive device and the rotational position detection device for the rotary plug 32.

On the other hand, the drive shaft 40 has a support body 60 that moves in a vertical guide groove 59 provided on the inner peripheral surface of the exchange body 45, and when the exchange body 45 rotates, the engagement between the guide groove 59 and the support body 60 is increased. The drive shaft 40 also rotates accordingly. Further, the hold-down shaft 41 is configured such that a lower portion 41A can rotate with respect to an upper portion 41B by a bearing 61. Therefore, when the drive shaft 40 rotates, the hold-down shaft 41A also rotates, and the grip portion 43 also rotates about the axis of the drive shaft 40.

During the reactor rated operation, the sodium at the core outlet is about 500
Although the temperature reaches ℃, the pressure of the cover gas is controlled to a predetermined value and does not rise significantly. Regarding the thermal deformation of the gripping part 43 of the fuel exchanger 33 and the sodium-immersed part such as the drive shaft 40 during the reactor rated operation, the extension of the drive shaft 40 when reaching the fuel exchange temperature (200 ° C) from room temperature is around 10 mm. Thus, the drive shaft 40 further extends about 20 mm when the reactor operating temperature (about 500 ° C.) is reached from the refueling temperature (200 ° C.). Any of these elongations can be absorbed by existing equipment. Further, when handling the fuel assemblies in the fuel storage rack 30a by the fuel exchanger 33 during the reactor operation, there is a space between the fuel assemblies and there is no interference with the adjacent fuel assemblies, so that Withdrawal and insertion can be performed smoothly, and handling performance equivalent to refueling during reactor shutdown can be obtained.

Also, regarding the shaft seal device 52 of the fuel exchanger door valve 51, the sodium vapor increases during the reactor rated operation, but by increasing the amount of fresh argon gas from the shaft seal device 52 into the reactor, the sodium vapor rises. Can be prevented. Moreover, since the pressure of the cover gas can be controlled to a predetermined value, a known shaft sealing device can be used as the shaft sealing device 52.

Since the fuel assemblies of only the fuel storage rack 30a are handled by the fuel exchanger 33 during the reactor rated operation, the influence of the flow rate distribution to the fuel assemblies in the core can be ignored.

Another embodiment of the present invention will be described with reference to FIGS. The same members as those shown in FIG. 1 are designated by the same reference numerals. The fuel handling equipment of this embodiment has a direct-acting type fuel exchange machine 70 and a fuel handling machine 71.The fuel exchange machine 70 is the same as the conventional direct-acting type fuel exchange machine, and the grip portion is only in the vertical direction. Can be moved. The fuel handling machine 71 has the same structure as the fuel exchange machine 33 described in the first embodiment, and is a conventional arm type fuel exchange machine having a rotation function.

The refueling machine 70 is mounted on the small rotation plug 32S, and the fuel handling machine 71 is on the rotation plug 7 located around the large rotation plug 32L.
Mounted on 2. Further, the fuel exchanger 70 is positioned so that the shaft center comes close to the outermost peripheral position of the core 21 in the fuel storage rack 73 at the reference stop positions of the large and small rotary plugs 32L, 32S.

A fuel storage rack 73 is installed adjacent to the core 21, which corresponds to the fuel storage rack 30a of the first embodiment. Therefore, in this embodiment, the fuel storage rack of the first embodiment is used.
There is no equivalent of 30b. Similar to the first embodiment, the fuel storage rack 73 has a circle centered on the drive shaft of the fuel handling machine 71 and having a radial movement stroke l of the gripping portion as a radius. It is arranged to be located in. Therefore, the fuel assemblies stored in the fuel storage rack 73 are within the operation range of the fuel handling machine 71. Further, an in-reactor relay rack 74 is arranged inside the circle outside the fuel storage rack 73. For this reason the fuel storage rack 73
The fuel can be transferred between the in-reactor relay rack 74 and the in-reactor rack 74 both during the reactor operation and during the reactor shutdown.

In such a fuel handling facility, while the reactor is shut down, the operation of the fuel exchanger 70 by the rotation of the rotary plug 32 and the fuel handling machine 71 cause the fuel storage immediately below the fuel exchanger 70 when the rotary plug is in the reference stop position. The portion of the rack 73 adjacent to the core is used as an in-core relay rack to exchange fuel in the core 21, and the spent fuel assemblies are stored in the fuel storage rack 73 for removal of decay heat. Rotating plug during reactor operation
32 and the refueling machine 70 are in a stopped state, the fuel assembly of the fuel storage rack 73 is handled by the fuel handling machine 71, and the fuel assembly is taken out of the reactor vessel via the relay rack 74 in the reactor for cleaning. carry out.

In the present embodiment as well, as in the first embodiment, the fuel assembly during the reactor operation can be taken out from the inside of the reactor vessel to the outside of the reactor vessel, and the diameter of the rotating plug can be made smaller than in the conventional case. Therefore, the size of the reactor vessel can be reduced.

Next, a preferred embodiment of the fuel bucket will be described with reference to FIG. In FIG. 10, the fuel bucket 80 is 4 at a time.
In order to accommodate the fuel assembly 81 of the body, it is divided into four chambers 82, and at the center thereof, a handling head portion 84 with which a grip portion 83 of the fuel inlet / outlet machine engages is provided.

According to the present embodiment, the grip portion 83 of the fuel inlet / outlet unit is easily
Since the fuel bucket 80 accommodating the spent fuel assemblies of the body can be handled, it is possible to store each fuel bucket 80 in the fuel cleaning tank, and a blower of a large capacity is manufactured to produce four spent fuel assemblies. By making it possible to perform the cleaning of all at once, it is possible to significantly reduce the time for refueling work.

EFFECTS OF THE INVENTION According to the present invention, the fuel exchange machine or the fuel handling machine is rotatable, and the fuel storage rack and the in-reactor relay rack are provided within the operation range by the rotation, so that the fuel storage is performed even during the operation of the reactor. The spent fuel assemblies in the rack can be taken out of the reactor vessel and cleaned, increasing the degree of freedom in fuel handling that was previously limited during reactor shutdown, and fuel during maintenance during reactor shutdown. At the time of replacement, cleaning of the fuel assembly, which conventionally took time, can be omitted, and the fuel replacement time during the maintenance period during reactor shutdown can be shortened.

Further, since the diameter of the rotary plug can be made small and the fuel storage racks are centrally provided at the lower part of the oblique road where there is a space in the conventional space, the diameter of the reactor vessel can be made small.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a fuel handling facility according to an embodiment of the present invention, FIG. 2 is a horizontal sectional view taken along line II-II of FIG. 1, and FIG. FIG. 4 is an enlarged view of a fuel storage rack portion, FIG. 4 is a view showing an example of a fuel exchange schedule according to the present embodiment, FIG. 5 is a vertical sectional view of a fuel exchange machine in the fuel handling facility, and FIG. FIG. 7 is an enlarged view of a part thereof, FIG. 7 is a vertical cross-sectional view of a fuel handling facility according to another embodiment of the present invention, and FIG. 8 is a view of the fuel handling facility of FIG. FIG. 9 is a vertical sectional view,
FIG. 10 is a plan view showing a positional relationship between a core and a fuel storage rack in the fuel assembly, FIG. 10 is a perspective view of a fuel bucket according to an embodiment of the present invention, and FIG. 11 is a conventional fuel handling facility. FIG. 12 is a plan view of the fuel handling equipment seen from above the reactor vessel, and FIG. 13 is a diagram showing an example of a fuel exchange schedule by the fuel handling equipment. Explanation of code 20 …… Reactor vessel, 21 …… Core 30a, 30b …… Fuel storage rack 31 …… Relay rack, 32 …… Rotating plug 33 …… Fuel exchanger, 40 …… Drive shaft 42 …… Grip, 43 …… Arm (connecting part) 70 …… Refueling machine, 71 …… Fuel handling machine 73 …… Fuel storage rack, 74 …… Relay rack

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-48-46792 (JP, A) JP-A-63-150693 (JP, A) JP-A-57-54896 (JP, A)

Claims (4)

[Claims] 1. A drive shaft comprising a connecting portion for varying a distance between a center of a holding portion for holding and releasing a fuel assembly in a nuclear reactor vessel and a center of a drive shaft passing through a rotary plug, and the drive shaft. A fuel exchanger that is configured to be rotatable about an axis and is mounted on a rotary plug, and a center of the gripping portion and a drive shaft about a drive shaft of the fuel exchanger when the rotary plug is at a reference stop position. When a circle is drawn with the maximum distance between the centers of the cores as a radius, a first fuel storage rack for storing fuel assemblies, which is arranged in this circle except for the core, and an in-reactor relay arranged in the circle A rack, and, in the reactor vessel, by a vertical plane including the core center axis,
When the rotary plug is divided into two parts, that is, the fuel exchange side and the non-fuel exchange side when the rotary plug is in the reference stop position, the first
2. A fuel handling facility for a fast breeder reactor, wherein all parts of the fuel storage rack and the in-reactor relay rack are arranged on the fuel exchanger side. 2. The fuel handling facility for a fast breeder reactor according to claim 1, wherein a second fuel storage rack is arranged at a position symmetrical with respect to the center of the core with respect to the first fuel storage rack. 3. The maximum value of the distance defined by the connecting portion between the center of the gripping portion and the center of the drive shaft is made equal to the radial length of the core component including the shield. Item 1. A fuel handling facility for a fast breeder reactor according to item 1. 4. A direct-acting type fuel exchanger mounted on a rotary plug, and a distance between a center of a gripping portion for gripping and releasing a fuel assembly in a reactor vessel and a center of a drive shaft passing through a fixed plug. A fuel handling machine that is equipped with a fixed plug and that is configured to be rotatable about an axis of the drive shaft, and the gripping portion around the drive shaft of the fuel handling machine. When a circle is drawn with the maximum distance between the center of the cylinder and the center of the drive shaft as a radius, a fuel storage rack for storing fuel assemblies, which is arranged inside the circle except the core, and a furnace arranged inside the circle. An inner relay rack, and when the inside of the reactor vessel is divided into two parts by the vertical plane including the core center axis into the fuel handling machine side and the anti-fuel handling machine side,
A fuel handling facility for a fast breeder reactor, wherein all parts of the fuel storage rack and the in-reactor relay rack are arranged on the fuel handling machine side.