JPH0159559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel loading/unloading machine for loading and unloading fuel assemblies for nuclear reactors, particularly fast breeder reactors that use liquid metal sodium as the primary coolant, from the nuclear reactor and transferring them to fuel storage equipment. Regarding preferred grippers.

The gripper of the fuel loading/unloading machine that handles the fuel assemblies for the fast breeder reactor mentioned above was suspended with high tensile strength stainless steel tape, and this tape was wrapped around it to make it easier to scrape off adhering sodium and clean it. By driving the winding drum, the entire gripper is raised and lowered, and the gripper claws are opened and closed. On the other hand, if the fuel were to drop or become stagnant during fuel transfer, it would immediately cause a serious problem in the operation of the reactor, so extremely high reliability is required. Ru. Further, the fuel assembly is transferred between the nuclear reactor and the fuel storage facility while being accommodated in a fuel transfer pot filled with sodium, and from the fuel storage facility the fuel assembly is transferred as is. From these points of view, it is desirable that fuel loading/unloading machines satisfy the following requirements. In other words, even if one of the tapes suspending the gripper were to break, the fuel would never fall and the subsequent operation would be possible without any problems. Even if a part of the operating mechanism inside the gripper becomes stuck and becomes inoperable due to deposits of etc.

By the way, the basic structure system in which the gripper is suspended by a pair (two tapes) to raise and lower the gripper and open and close the claws has already been put into practical use and has achieved stable operation results. In addition, in order to safely support the fuel without causing it to fall even if one of the tapes breaks, the gripper is suspended in advance with two pairs (four tapes), and if one tape breaks, the gripper is immediately suspended. The load is supported by a pair of healthy tapes, and the gripper is suspended by two pairs of tapes, and even if one of the tapes becomes inoperable, the gripper can be disconnected from the fuel in an emergency. There have been suggestions for improvements that could be made, but
These existing proposals have complex structures that are far from the basic structures that have been used in operation, and there are considerable problems in demonstrating high reliability in actual commercialization.
In addition, when changing the object to be handled by the fuel loading/unloading machine from transferring a single fuel assembly to transferring a fuel transfer pot, or vice versa, each time the gripper tip is changed to a different one with a different shape and size. However, with conventional methods, the fuel inlet/output machine must be moved to a maintenance area, the grippers must be cleaned there, and then a worker must approach the gripper and replace the gripper tip directly by hand. However, there remain problems with the length of time required for replacement work and the safety of workers against radiation exposure.

The present invention has been made in consideration of the above points, and its purpose is to skillfully combine the basic mechanical parts adopted in grippers that are currently in actual operation and have a proven track record, and to solve the problem of breaking any tape. To provide an advantageous gripper which can safely maintain suspension of fuel even when an emergency occurs and can reliably disconnect the fuel in an emergency.

Hereinafter, embodiments of the present invention for achieving the above object will be described in detail based on illustrated embodiments.

First, in FIG. 1, 1 is the gripper upper base;
Reference numeral 2 indicates a gripper tip fitting the fuel transfer pot, 2' indicates a gripper tip fitting fitting the fuel assembly, and 3 and 3' indicate the fuel transfer pot and the upper end handling head of the fuel assembly, respectively. , especially the lower left half of the figure is the tip body 2',
The right half is equipped with the tip body 2 and the object to be handled 3,
3' is shown.

The basic structure of the gripper according to the present invention consists of the above-described combination of the gripper upper base body 1 and the gripper tip body 2 or 2'. The upper base 1 has two sets of drums 5 and 6 mounted vertically in a cylindrical casing 4. As clearly shown in the sectional views of FIGS. 2 and 3, each set of drums 5 and 6 consists of two rows of drums supported by a bearing 7 fixed to the casing 4. Two pairs of independent hanging tapes 8 and 8' and 9 and 9' are wound and connected to the drums 5 and 6, respectively. Further, in the lower end area of the casing 4, a plurality of intermediate connecting pawls 10 are arranged in the circumferential direction and are attached to pins 11 such that the tips of the pawls protrude from the outer periphery of the casing.
An actuator 12 for opening and closing the pawl opposite the intermediate connecting pawl 10 is connected to one of the drums 5 through a crankshaft 13. The claw opening/closing operation mechanism composed of the drum 5, tapes 8, 8', crankshaft 13, actuator 12, and claw 10 described above is similar to the claw opening/closing operating mechanism currently used in grippers that have a proven track record. By operating drums 8 and 8' in opposite directions, the drum 5
The crankshaft 13 moves the actuator 12 up and down to open and close the pawl 10. A gripper claw opening/closing actuator 15, which will be described later, is connected to the other drum 6 via a crankshaft 14 projecting downward from the upper base 1. On the other hand, the gripper tip bodies 2 and 2' each have a gripper claw 17, which is opened and closed by the operation of the actuator 15, attached to cylindrical claw holders 16 and 16'.
17', the claw holder 16,
The upper end of the gripper 16' is formed as a handling head which is fitted into the lower end of the gripper upper base 1 in a ferrule type and coupled with the intermediate connecting pawl 10;
The lower tip is shaped to match the size and shape of the handling head of the fuel transfer pot 3 or fuel assembly 3'. Also Gritspa claw 1
7, 17' are pivotally supported by pins 18, 18' in the pawl holders 16, 16' in the same way as the intermediate connecting pawl 10, and the tips of the pawls are laterally positioned from the tips of the pawl holders 16, 16'. It is installed so that it can swing so that it protrudes. Therefore, in the fuel transfer pot tip body 2, the gripper claws 17 directly face the actuator 15, whereas the small diameter fuel assembly tip body 2'
In this case, an intermediate lever 19' and an operating lever 20' are interlocked and connected to the gripper claw 17', and the operating lever 20' is located opposite to the actuator 15. Therefore, by operating the hanging tapes 9, 9' in opposite directions for either of the tip bodies 2, 2', the drum 6 rotates and moves the actuator 15 up and down, which is interlocked with this. Grip claw 17 or 17'
will be opened and closed. Furthermore, the gripper claws 1 are attached to the upper end handling heads of the claw holders 16, 16' in the gripper tip bodies 2, 2'.
7, 17' Two stages of handling engagement grooves 21, 2 with pitch intervals corresponding to the vertical movement stroke of the actuator 15 for opening and closing operations.
2, 21', 22' are formed.

By the way, as shown in FIG. 4, each pair of hanging tapes 8, 8', 9, 9' connected to the built-in drums 5, 6 of the gripper upper base 1 is connected to the winding drum mounted on the fuel intake/discharge machine at the upper part. They are individually wound around winding drums 24, 25, 26, and 27 installed within the case 23. Further, the drum shafts of each of the winding drums 24 to 27 are connected to a drive mechanism 28. The drive mechanism 28 is composed of a drive motor 29, a reduction gear 30, and an interlocking mechanism that combines a clutch and an interlocking gear train, as shown by dotted lines 31, and operates the winding drums 24 to 27 interlockingly or individually based on an operation command. Drive rotation.

Next, the operation of the gripper will be described. First, the objects to be handled are the fuel transfer pot 3 and the fuel assembly 3'.
The gripper tip body is selected depending on which one is to be transferred. That is, in the former case, the tip body 2 for the fuel transfer pot is selected, and in the latter case, the tip body 2' for the fuel assembly is selected, and the gripper upper base 1 is suspended from above to handle the tip body. After fitting into the head, the intermediate connecting claw 10 is engaged with the lower engagement grooves 22 to 22' of the tip body to connect the two. The situation at this time is shown in FIG. The gripper upper base 1 is suspended by four tapes 8, 8', 9, 9', and in order to move the upper base 1 up and down, each winding drum 24--
27 in conjunction with each other to drive each tape up or down. Further, in order to open and close the intermediate connecting claw 10, the relative position of the tapes 8 and 8' is adjusted by rotating the winding drums 24 and 25 in opposite directions while keeping the winding drums 26 and 27 stopped and locked. The drum 5 rotates due to the movement, and the intermediate connecting pawl 10 is opened and closed. Now, with the gripper tip body 2 or 2' connected to the upper base body 1, the fuel injector is moved to a predetermined fuel handling position, where the entire gripper is suspended above the object to be handled. Next, by driving the winding drums 26 and 27 in opposite directions while keeping the winding drums 24 and 25 stopped and locked, the drum 6 is rotated by operating the tapes 9 and 9'.
The gripper pawls 17 or 17' are brought into engagement with the object to be handled. Thereafter, the object to be handled is lifted to a predetermined handling position by lifting and lowering the entire gripper and moving the fuel inlet/outlet machine while gripping the object, and one fuel transfer is completed by cutting off the gripper claws here. .

By the way, during the fuel transfer, the tapes 8, 8',
Even if one of the tapes 9 or 9' breaks, the hanging load will be supported by the remaining pair of healthy tapes, so the gripper will not fall and the object to be handled will be taken over. The transfer can be continued without any stagnation. In addition, if the broken tape is either 8 or 8', there will be no hindrance to the opening/closing operation of the gripper claws 17 or 17'.
Can be separated from the object to be handled. However, if the tape breaks at either 9 or 9', the built-in drum 6 cannot be rotated, and the object to be handled cannot be separated by normal operation. In this case, first, with the object to be handled suspended on the rack, the drum 5 is rotated by manipulating the pair of healthy tapes 8, 8', and once the intermediate connecting claw 10 and the engaging groove are 22 to 22' are separated. Next, pull up the gripper upper base 1 by a predetermined distance,
By operating the tapes 8, 8' again, the intermediate connecting claw 10 is now connected to the upper engagement grooves 21 to 21'. During this process, the built-in drum 6 remains stationary and rises together with the upper base 1, so as shown in FIG. ' is moved to the closed position to release the connection between the claws 17 or 17' and the object to be handled.
Therefore, if the entire gripper is lifted upward in this state, emergency separation between the gripper and the object to be handled can be performed. This emergency disconnection operation can be applied not only when the tapes 9, 9' break, but also when the rotation of the drum 6 becomes impossible due to the accumulation and solidification of sodium.

As is clear from the above description, according to the present invention, the handling head of the gripper tip body is arranged at a pitch interval corresponding to the vertical stroke of the actuator for operating the gripper claws, and the upper and lower grippers face the intermediate connecting claws of the upper base of the gripper. A two-stage handling engagement groove is provided, and by operating the hanging tape, the intermediate connecting claw operation actuator is moved up and down to move the intermediate connecting claw to the upper or lower stage of the handling head of the gripper tip body. The gripper claws are engaged with the engagement grooves, and the actuator for operating the gripper claws is moved up and down to connect and disconnect from the object to be handled, so the above functional conditions required for the gripper are met. The gripper mechanism ensures safety when the tape breaks and allows for emergency separation from the object to be handled, and the reliability of each mechanical part that makes up the gripper has been proven through actual operation results. Grippers with the same structure as the parts can be used as is, making it possible to provide grippers with excellent functionality and reliability.

[Brief explanation of drawings]

Each figure shows an embodiment of the present invention, and FIG. 1 is a vertical sectional view in a normal operating state, FIGS. 2 and 3 are sectional views taken in the direction of arrows - and - in FIG. A drive system diagram of the gripper, FIG. 5 is a vertical cross-sectional view showing a state in which the gripper upper base body and tip body are separated, and FIG. 6 is a vertical cross-sectional view showing a state in which the fuel is emergency disconnected. 1: Gripper upper base body, 2: Gripper tip body, 4: Casing, 5, 6: Drum, 8, 8',
9, 9': Hanging tape, 10: Intermediate connecting claw, 1
2, 15: actuator, 13, 14: crankshaft, 16, 16': pawl holder, 17, 17': gripper pawl, 21, 21', 22, 22': engagement groove for handling.

Claims (1)

[Claims] 1. Two sets of drums each operated independently by a pair of hanging tapes are loaded in a casing, and the upper base of the gripper has an intermediate connecting claw protruding to the outer periphery at the lower end of the casing, and the tip is connected to the object to be handled. A gripper tip body is provided with a gripper pawl in a pawl holder shaped to match the dimensions of the handling head of the gripper, and is suspended and connected to the gripper upper base body via the intermediate connecting pawl, and a crank is attached to each of the two sets of drums. In a gripper comprising an actuator for operating intermediate connecting claws or an actuator for operating gripper claws connected via a shaft, the handling head of the gripper tip body has a pitch interval corresponding to the vertical stroke of the actuator for operating the gripper claws. The handler is provided with two stages of upper and lower handling engagement grooves that are defined and opposite to the intermediate connecting pawl of the gripper upper base, and the actuator for operating the intermediate connecting pawl is moved up and down by the operation of the hanging tape, and the intermediate connecting pawl is moved up and down by the operation of the hanging tape. engaging the upper or lower handling engagement groove of the handling head of the gripper tip body, and moving the gripper claw operating actuator up and down;
A gripper for a fuel loading/unloading machine, characterized in that it is configured to connect and disconnect from an object to be handled.