JPH0110635Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a handling device for a fuel assembly for a nuclear reactor.

A fuel assembly commonly used in pressurized water reactors consists of a plurality of elongated fuel rods and a plurality of guide tubes (thimbles) distributed between them, bundled together by a support grid. It is supported in a shape.

The thimble is mainly used for inserting control rods (which are moved vertically by a drive device above the reactor vessel), but the arrangement of the control rods in the reactor core is
A specific distribution is shown due to reasons such as reaction control.

Mainly due to manufacturing reasons, the geometric positional relationship between fuel rods and thimble in multiple fuel assemblies (approximately 100 or more) used in the same nuclear reactor is the same, so each fuel All or some of the thimbles of the assembly may not be used for control rod insertion.

Some of the thimbles that are not used for inserting control rods are used for in-core instrumentation, etc., but other thimbles are closed with thimble plugs due to thermo-hydraulic requirements.

On the other hand, since the burnup of the fuel assemblies loaded in the core differs depending on their position in the core, their horizontal position in the core is changed during refueling, which is usually done once a year.

Therefore, it is necessary to replace the plug inserted into the thimble.

The device of the present invention removes and attaches the plug inserted into the thimble of such a fuel assembly.

Such attachment and detachment of the thimble is carried out remotely by suspending the device from above the water surface with respect to the fuel assembly placed deep in the water.

A conventional handling device is suspended by a crane or the like and engaged with the upper end plate (nozzle) of a target fuel assembly via a guide pin and a positioning pin at the lower end of the device.

After that, when the crane hook is lowered, the housing holding the thimble plug at the lower end protrudes from the lower end of the equipment due to the weight of the equipment, and the plug is inserted into the thimble (when installing the plug). In the device, even if the guide pin did not enter the predetermined position, if it hit another part, the plug would protrude from the bottom end of the device, potentially causing damage.

Therefore, there is a problem in that the positioning and engagement of the device must be performed carefully, and the work requires a considerable amount of time.

The present invention was developed in view of the above-mentioned circumstances, and involves attaching a locking device to the plug handling tool that holds the plug at the lower end, thereby completely eliminating the need for positioning and engaging the fuel assembly as well as inserting and removing the plug. It is an object of the present invention to provide a handling device which prevents damage to the plug by separating the plug.

Hereinafter, the present invention will be explained based on the illustrated embodiments.

In FIG. 1, the upper end of a hollow connecting pipe 3 is fixed to a hanging fitting 1 that is hung on a crane hook (not shown), and a support flange 5 and a stop flange 7 are formed at the center and lower ends of the connecting pipe 3, respectively. has been done.

The legs of the guide frame 9 slidably fitted to the lower end of the connecting pipe 3 are located outside the stop flange 7, and a guide pin 11 and a positioning pin 13 are protruded from the lower end. Guide pin 11
is inserted into a guide hole in the upper end plate of a fuel assembly (not shown), and the positioning pin 13 is similarly inserted into a positioning hole in the upper end plate.

A spring 15 is interposed between the lower surface of the support flange 5 and the upper end flange of the guide frame 9.

At the upper end of the operating rod 21 inserted into the connecting pipe 3,
A plurality of thimble plugs 27 are seated on the lower surface of the housing 25, to which the operating handle 23 is attached and which is attached to the lower end thereof, and protrude downward.

After the plug 27 is inserted into the upper opening of the thimble of the fuel assembly (not shown), the plug handling tool 20
When you grasp the handle 23 and move the operating rod 21,
The plug 27 and the housing 25 are separated (in the case of attaching the plug 27).

Supports 31 and 33 of the locking device 30 provided above the support flange 5 are fitted onto the outer surface of the connecting pipe 3, and a handle 37 is fixed to the upper end of an operating rod 35 inserted through the supports 31 and 33. .
The handle 37 is located near the hanging fitting 1 and can be directly operated by an operator from an operation console (not shown).

The lower part of the operating rod 35 extends to the vicinity of the upper end flange of the guide frame 9, and a stopper 39 is provided to protrude laterally. A sub-operation rod 41 extending parallel to the operation rod 35 is rotatably supported by the support 33, and has a stopper 39 protruding from its lower end.

As is clear from FIG. 3, arms 43 and 45 are respectively locked to the operation rod 35 and the sub-operation rod 41.
are connected by a bar 47 to form a parallel link.

In this embodiment with the above-described configuration, the procedure for attaching the plug will be described. Water is filling the reactor vessel (not shown) and the reactor cavity (the lid is open), and the target fuel assembly is being filled with water. is placed upright inside the reactor vessel. Then, the hanging fitting 1 is hung on the hook of a crane (not shown), the crane is operated, and the entire apparatus is positioned directly above the fuel assembly.

In this state, the stopper 39 is in the position shown and limits the upward movement of the guide frame 9.

After that, operate the crane, lower the entire device while visually checking the fuel assembly, and remove the guide pin 11.
into the guide hole of the upper end plate (not shown). When the hook is lowered further, the device is lowered and the locating pin 13 fits into the locating hole in the upper end plate.

If you lower the hook further, the weight of the device will be reduced to 15
acts on and shrinks. Therefore, the housing 25 holding the plug 27 approaches the lower end of the guide frame 9, but the stopper 39 of the locking device 30 comes into contact with the upper end flange of the guide frame 9, preventing the connecting pipe 3 and the handling tool 20 from descending. limited.

After visually confirming that the positioning is complete, the handle 37 of the locking device 30 is moved to the second position.
Turn it in the direction of the arrow in the figure and Figure 3. Operation rod 35
The rotation is transmitted to the auxiliary operating rod 41 via the arms 43, 45 and the bar 47, so the stopper 39 rotates and comes off the upper end flange of the guide frame 9. As a result, the own weight is further added to the spring 15,
Shrink further. The handling tool 20 is lowered, and the housing 25 and plug 27 protrude from the lower end of the guide frame 9. The plug 27 is then inserted into the upper opening of the thimble of the fuel assembly.

Next, the handle 23 and the operating rod 21 are moved to separate the plug 27 and the housing 25, and then the hook of the crane is raised, the device is separated from the fuel assembly and the installation of the plug 27 is completed.

According to the above-described embodiment, the plug 27 can be projected below the guide frame 9 only after the lock device 30 is operated after visually confirming the completion of positioning. 27 does not protrude and its damage can be completely prevented.

[Brief explanation of the drawing]

FIG. 1 is an elevational sectional view showing an embodiment of the present invention, FIG. 2 is a plan view taken from the - line direction of FIG. 1, and FIG. 3 is a plan view similarly taken from the - line direction. 3... Connecting pipe, 5... Support flange, 9... Guide frame, 13... Positioning pin, 15...
Spring, 20...Handling tool, 27...Plug, 30
...Lock device, 37...handle.

Claims (1)

[Scope of utility model registration request] A connecting pipe suspended from a crane hook, a guide frame slidably fitted to the outside of the lower part of the connecting pipe, a spring interposed between a support flange at the center of the connecting pipe and the guide frame, and the guide frame. The guide frame includes a positioning pin protruding from the lower end, a plug handling tool including an operating rod penetrating the connecting pipe, and a handle fixed to the upper part of the connecting pipe and located near the upper end of the connecting pipe. 1. A nuclear reactor fuel assembly handling device comprising a locking device for selectively restricting relative lift.