JPS6032155B2 - nuclear reactor refueling machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to refueling in liquid metal cooled fast reactors.

Generally, in refueling a liquid metal cooled fast reactor, the first step is to disconnect the control rod installed at the top of the reactor pressure vessel, and then remove the core upper mechanism and core components, which are integrated with the rotating plug of the reactor pressure vessel. After completely separating the rotary plug, the rotary plug is rotated, the refueling machine provided on the rotary plug is positioned over the fuel assembly to be replaced, and the gripper of this refueling machine is attached to the handling head of the fuel assembly. 'The fuel assemblies were exchanged in a row.

By the way, when rotating the above-mentioned rotary plug, if the control rods are not completely released or if the reactor components are floating and interfering with the upper core mechanism, This could have caused catastrophic damage to the reactor core. To prevent this, the reactor was equipped with sodium fluoroscopy equipment that emitted ultrasonic waves into the reactor and received the reflected waves of the emitted ultrasonic waves to confirm the separation between the core and the upper core mechanism. However, the provision of such a device had the problem of complicating the structure of the furnace. In addition, in the event that the positioning device of the fuel exchanger malfunctions, there is a possibility that a fuel assembly different from the designated fuel assembly will be replaced, causing an abnormality in the power distribution of the core and affecting the integrity of the reactor. In addition, when such a problem occurs, it takes a lot of time to identify the fuel assembly in which the abnormality has occurred. Additionally, if the fuel assembly in the gripper of the fuel exchanger is not fully connected, the fuel assembly will not be pulled out even if the fuel exchanger is operated, and even if you try to insert the next new fuel without knowing this, the insertion will not be possible. There was a problem that required a lot of time to investigate the cause. In order to prevent such problems, a retractable pin is installed in the gripper of the fuel exchanger.
When the gripper completely competes with the handling head of the fuel assembly, the above-mentioned pin contacts and sinks into the handling head of the fuel assembly, thereby detecting whether or not the gripper has completely gripped the fuel assembly. Although a mechanism is provided, such a mechanism tends to cause pins to become restricted because it operates in high-temperature liquid metal, and its operation is less reliable. Further, with such a mechanism, it is impossible to detect whether or not the gripper has gripped the correct fuel assembly. The present invention was made based on the above circumstances, and its purpose is to be able to detect whether the core and the upper core mechanism are completely separated or not when the rotating plug rotates, and to enable the gripper to correctly assemble the fuel assembly. The object is to be able to reliably detect whether or not the device is gripped, and to obtain fuel exchange for a nuclear reactor with a simple structure ≠ Okuiso.

The present invention will be explained below according to an embodiment shown in the drawings.

1 in the figure is a reactor pressure vessel, and the upper end of this reactor pressure vessel 1 is closed by a rotating plug 2. This rotating plug 2 is composed of a large rotating plug 3 and a small rotating plug 4, and The plug 4 is provided eccentrically with respect to the large-rotation plug 3.Furthermore, 5 is a core, and a core upper mechanism is provided above the core 5, and this core upper mechanism 6 is used for the small rotation. The control rods (not shown) are guided by the core upper mechanism 6 and inserted into the reactor core 5.The small rotating plug 4 is equipped with fuel. An exchanger 7 is attached to the refueling machine 7. A gripper tube 8 that penetrates the small rotating plug 4 and is inserted into the furnace is provided.
A gripper 9 is attached to the lower end of. Also, 10
is a rotational drive mechanism, and is configured so that the gripper tube 8 and the gripper 9 are rotated by this rotational drive mechanism 110. Further, reference numeral 11 denotes an elevating drive mechanism, and the gripper tube 8 is moved up and down by this elevating drive mechanism 11, and is configured to be inserted into the furnace. The gripper 9 described above is configured as follows. Reference numeral 12 designates the housing, and a conical guide portion 13 is formed at the lower end of the housing 12. In this guide portion, reference numeral 3 designates the handling head turtle 5 of the fuel assembly 14.
is configured to have an insert conflict.

A plurality of claw members 16 are pivotally attached to the lower part of the housing 12 so as to be rotatable in the radial direction. Fish-shaped locking portions 17 are formed at the lower ends of these claw members 16. Further, an operating shaft 18 is provided within the gripper tube 8 and the housing 12 so as to be freely slidable along their central axes. A cam body 19 is attached to the lower end of the operating shaft 18, and the upper ends of the claw members 16 are in contact with the cam body 19, respectively. When the operating shaft 18 is slid by an operating mechanism (not shown), the claw members 16 are rotated by the cam body 19, and the locking portions 17 of the claw members 16 protrude and retract in the radial direction, causing the fuel It is configured to engage and disengage from the inner surface of the upper edge of the handling head 15 of the assembly 14. Further, the guide section 13 includes an ultrasonic oscillation receiver 20 built therein. This ultrasonic oscillation receiver 201 is configured to emit ultrasonic waves and receive reflected waves thereof, thereby detecting the presence of members in the furnace, their positions, and the like. This ultrasonic oscillation receiver is housed in a recess 21 formed in the guide portion 13 and is oriented outward in the direction of the folding. This ultrasonic oscillation receiver 20' has a rotation shaft 22 that protrudes along the horizontal direction.
It is rotatably supported in the vertical direction. A drive arm 23 is provided on the back of this ultrasonic oscillation receiver 20.
, 23 are provided protrudingly, and a drive pin 24 is provided along the horizontal direction between the tips of these drive arms 23, 23. Further, a drive shaft 25 is provided at the lower end of the cam body 19 to protrude downward, and a drive groove 26 is formed in an intermediate portion of the drive shaft 25 in a direction perpendicular to the axial direction of the drive shaft 25. There is. The drive pin 24 of the ultrasonic oscillation receiver 20 is slidably fitted in the drive groove 26, and by sliding the operating shaft 18 in the direction of the ball, the drive pin 24 is inserted through the drive pin 25. 24 is moved up and down, and the ultrasonic oscillation receiver 20 is rotated in the up and down direction.
A signal cable 27 connected to the ultrasonic oscillation receiver 20 passes through the housing 12 of the gripper 9 and the gripper tube 8 and is led out of the furnace. Further, reference numeral 28 denotes a detection pin, which is provided so as to be able to protrude and retract downward from the lower part of the housing 12, and is biased in the protruding direction by a spring 29. and,
The upper end of this detection pin 28 is connected to a detection rod 30 inserted into the operating shaft 18. When the gripper 9 is completely inserted into the handling head 15 of the fuel assembly 14, the lower end of the detection pin 28 comes into contact with the upper green end of the handling head 15, and this movement causes the detection rod 30 to It is configured such that the gripping of the fuel assembly 14 can be mechanically detected by being transmitted to the outside through the grip. In one embodiment of the present invention configured as described above, first, all control rods and control rod drive mechanisms are disconnected prior to fuel exchange, and the reactor core 5 and upper core mechanism 6 are completely separated.

Next, the gripper tube 8 is lowered and inserted into the reactor, and the gripper 9 is positioned between the reactor core 5 and the upper core mechanism 6. Next, the operating shaft 18 is operated to rotate the ultrasonic oscillation receiver 20 up and down, and adjust the ultrasonic oscillation receiver 20 so that it is accurately oriented in the horizontal direction. Next, the gripper tube 8 and the gripper 9 are rotated once, and the ultrasonic waves oscillated from the ultrasonic oscillation receiver 20 are used to connect the reactor core 5 and the reactor upper mechanism 6.
Scan the gap between Therefore, if the control rods are not separated or if a component of the reactor core 1 is lifted up and interferes with the upper core mechanism 6, the emitted ultrasonic waves will be reflected at that part and cause ultrasonic wave oscillation. The signal is received by the receiver 20, and it is detected that the core 5 and the upper core mechanism 6 are not completely separated. Therefore, if the rotating plug 2 is rotated without knowing this, damage to the reactor core 5 can be reliably prevented.When it is confirmed that the reactor ○5 and the upper core mechanism 6 are completely separated, the large rotating plug 3 and the small rotation plug 4 are rotated, and the gripper 9 is to be replaced.
Position it directly above 4. Next, the gripper tube 8 is lowered and the gripper 9 is brought into contact with the handling head 15 of the fuel assembly 14. In this case, the guide 13 of the gripper 9
When the ultrasonic oscillation receiver 20 is completely aligned with the handling head 15, the ultrasonic oscillation receiver 20 faces the inner surface of the upper end of the handling head 15, so that the gripper 9 is completely aligned with the handling head 15. It will be checked whether it was done or not. Further, in this case, since the detection pin 28 comes into contact with the upper green part of the handling head 15 and retracts, it is also detected whether the gripper 9 has completely competed with the handling head 15 based on the displacement of the detection pin 28. Next, the gripper 9 is rotated. Then, the ultrasonic oscillation receiver 20 reads the groove corresponding to the number of the fuel assembly 14 formed in the upper green part of the handling head 15.
It is detected whether or not the gripper 9 has engaged with the correct fuel assembly 14. Next, the operating shaft 18 is operated to rotate the pawl member 16, and the locking portion 17 thereof is engaged with the upper twill portion of the handling head 15. Next, raise the gripper tube 8,
Pull out the fuel assembly 14. In this embodiment, by simply providing the ultrasonic oscillation receiver 20 in the gripper 9, the separation between the core 5 and the upper core mechanism 6 can be confirmed, and the gripper 9 can be completely attached to the handling head 15 of the fuel assembly 14. It is possible to check whether or not the drums are in agreement and to check the number of the fuel assembly 14, and the structure is simple. In addition, since the operating shaft 18 for operating the claw member 16 is used as the driving mechanism for moving the ultrasonic oscillation receiver 20 in the vertical direction, the structure is simple, and only modifications are required to the existing fuel exchanger 7. The present invention can be easily implemented. Note that the present invention is not limited to the above embodiment.

For example, the rotation drive mechanism that rotates the ultrasonic oscillation receiver in the vertical direction is not necessarily limited to the one described above.

Further, it is not necessarily necessary to provide a mechanism such as a detection pin for mechanically detecting whether or not the gripper is completely engaged with the fuel assembly.

In addition, the structure of the gripper etc. is not necessarily limited to the above-mentioned structure, and any structure may be used as long as it has a gripper that can be raised and lowered and rotated freely.

As described above, the present invention is provided with an ultrasonic oscillation receiver that oscillates ultrasonic waves and receives the reflected waves on the gripper of a fuel exchanger so as to be rotatable in the vertical direction.

Therefore, this ultrasonic oscillation receiver can be used to confirm whether the core and upper core mechanism have been completely separated, to confirm whether the gripper has been completely fitted to the handling head of the fuel assembly, and to confirm the number of the fuel assembly. This makes it possible to reliably prevent damage to the reactor core when rotating the rotary plug, as well as reliably prevent fuel loading, and refueling operations can be carried out reliably and efficiently. Further, since the gripper is simply provided with an ultrasonic oscillation receiver, its structure is extremely simple, and its effects are great.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view of the whole, Fig. 2 is a longitudinal sectional view of the main part, and Fig. 3 is a longitudinal sectional view of the main part in a state where it is iron-coupled with a fuel assembly. 4 is a side view of the ultrasonic oscillation receiver, FIG. 5 is a plan view thereof, and FIG. 6 is a side view of the main part of the drive shaft. 1... Reactor pressure vessel, 2... Rotating plug, 3... Large rotating plug, 4... Small rotating plug, 5... Reactor core, 6
...Furnace ○ upper mechanism, 7...Fuel exchange machine, 8...Gripper tube, 9...Gripper, 10...Rotation drive mechanism, 11...Elevating drive mechanism, 14...Fuel assembly Body, 15... Handling head, 16... Claw member, 1
8... Operating shaft, 19... Cam body, 20... Ultrasonic oscillation receiver, 22... Rotating shaft, 24... Drive pin, 25... Drive shaft, 26... Drive groove. Figure O, Figure 2, Figure 3, Figure Om, Figure 5, Figure 6.

Claims (1)

[Scope of Claims] 1. A gripper tube provided on a rotary plug of a reactor pressure vessel so as to be able to move up and down and freely rotate, a gripper provided at the lower end of this gripper tube, and a gripper provided horizontally to a handling head of a fuel assembly of this gripper An ultrasonic oscillation receiver that emits ultrasonic waves and receives the reflected waves, which is attached to the gripper and is rotatable in the vertical direction with respect to the gripper. A fuel exchange machine for a nuclear reactor, characterized in that it is equipped with a rotary drive mechanism that rotates and drives. 2. The rotary drive mechanism according to claim 1, wherein the operating shaft for gripping and releasing the gripper is also used for rotationally driving the ultrasonic oscillation receiver. Refueling machine for nuclear reactor.