JPH0758352B2 - Suction-type collection method for clad in pressure pipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a trapping device in which water containing clad separated from the wall of a pressure tube in a pressure tube reactor is attached to the tip of a refueling machine. Suction with a pump and filter the clad
The present invention relates to a method of adsorbing to a unit and collecting it.

[Prior Art] In a pressure tube reactor, a clad (corrosion product) is generated on the inner wall of the pressure tube due to long-term use. This clad hinders ultrasonic flaw detection, dimension measurement, and visual inspection of the inner surface during pressure tube monitoring.

Therefore, it is necessary to regularly remove the clad adhering to the inner wall of the pressure pipe. In the prior art, it was possible to mechanically remove the clad with a wiper or the like.

[Problems to be Solved by the Invention] However, a method for effectively collecting the separated clad has not been technically solved yet.

For example, if you try to collect with a filter etc. somewhere in the system while operating the coolant purification system, there will be a considerable amount of clad in the pipes of the coolant recirculation system and coolant purification system or the heat transfer tubes of the heat exchanger. It will be attached, and it will have a great effect on radiation exposure during regular inspections.

It is also conceivable to suspend the operation of the system and deposit the clad in the refueling machine, but such a method may cause a dramatic increase in the dose of the refueling machine and cause mechanical failure of the refueling machine. Absent.

Furthermore, even if an attempt is made to remove the clad at the same time as monitoring the pressure tube, the clad may enter a gap or the like in the monitoring device and the device may not operate normally, which makes it difficult to carry out.

Moreover, as shown in FIG. 4, there was no foothold in the vicinity of the fuel exchanger 12 below the pressure pipe 10 and work at high places was required, so there was a considerable restriction in terms of equipment, and an appropriate method could not be found. .

The object of the present invention is to solve the technical problems that the above-mentioned conventional techniques have, and to efficiently collect the clad in the pressure pipe without unnecessarily diffusing it, and therefore to prevent the exposure in various operations after removal. It is an object of the present invention to provide a method of collecting clad in a pressure pipe, which can prevent the increase, can be easily installed, and can be inexpensively handled by using a conventional device.

[Means for Solving the Problems] The present invention that can achieve the above-described object is to provide a spacer having a space having a longitudinally extending space in the center and a pump that is detachable from the spacer. A collection device consisting of a filter unit is attached to the tip of the refueling machine, moved to the lower end of the pressure pipe, and the clad separated from the pressure pipe surface is sucked together with water by the pump and adsorbed to the filter unit. After the adsorption work is completed, it is a suction type collection method of the clad in the pressure pipe, which is detached from the tip of the refueling machine. Here, the collecting device is a spacer having a cylindrical shape having a space vertically extending in the center and a filter unit accommodating space in the upper part, and a filter unit detachable in the filter unit accommodating space above the spacer.
A unit and a pump mounted outside the spacer,
The structure is composed of pipes that connect between the bottom of the filter unit housing space and the pump, and between the pump and the space at the center of the spacer.

The clad can be peeled off from the inner wall of the pressure pipe mechanically, for example, by sliding a wiper or the like in the pipe.

[Operation] The clad adhering to the inner wall of the pressure pipe is peeled off from the inner wall of the pipe by a sliding operation such as a wiper. If the system is temporarily stopped and the pump installed in the collector is activated, the clad mixed water will flow through the filter unit. At that time, the clad is adsorbed and collected by the filter unit. Therefore, there is no possibility that the clad unnecessarily diffuses inside the system.

The clad adsorbed to the collector is removed from the fuel exchanger alone or with the filter unit alone, and the filter unit is taken out and transferred to the waste storage for storage.

In terms of equipment, it is easy to deal with the situation by modifying the tip of the currently used fuel exchanger to some extent so that a collecting device can be attached.

[Embodiment] FIG. 1 is a process explanatory view showing an embodiment of the clad collecting method according to the present invention.

First, as shown in A of the same figure, the collecting device 14 is lifted by a crane or the like (not shown) and attached to the tip 16 called the "snout part" of the fuel exchanger 12 (see B of the same figure).
If a step (not shown) is provided on the inner surface of the tip portion 16, the collection device 14 can be easily attached.

The refueling machine 12 is located below the pressure tubes 10 which are regularly arranged as shown in FIG. 4, and is configured to be freely movable in a horizontal plane. This refueling machine 12
In addition to exchanging fuel, a pressure pipe monitoring device can be inserted into a predetermined pressure pipe at the time of pressure pipe monitoring, and various inspections can be performed by the monitoring device alone.
In the present invention, such a fuel exchanger 12 is also used for collecting the clad.

As shown in FIGS. 2 and 3, the trapping device 14 used in the present invention includes a suction pump 40, a spacer 44 having a space 42 vertically extending in the central portion thereof, and a spacer 44 that can be attached to and detached from the spacer 44. It is composed of a flexible filter unit 46 and the like, and has a structure such that the shaft of a wiper for removing clad can be freely inserted.

A step portion 48 is provided on the inner peripheral side of the upper portion of the spacer 44, and an annular filter unit 46 is placed on the step portion 48 and is held by a pressing member 50. A large number of suction ports 52 are opened on the upper surface of the pressing member 50 to accommodate the filter unit 46.
Pipes 56 and 58 are connected between the bottom of 54 and the pump 40, and between the pump 40 and the space 42, respectively.

As shown in FIG. 1C, the fuel exchanger 12 equipped with the collector 14 is moved to the lower end of a predetermined pressure pipe 10 where the clad should be removed by a moving mechanism in the horizontal plane. Then slide the cladding removing wiper 18 up and down on the shaft 20,
The clad 22 attached to the inner wall of the pressure pipe 10 is mechanically peeled off.

During this time, the system operation was temporarily stopped and the pump
When 40 is energized and driven, a flow of clad mixed water occurs as shown by the arrow in FIG. 1D. The clad 22 is filtered and adsorbed by the filter unit 46. The filtered water flows out through the pipe by the pump 40.

Such an operation is performed on the pressure tube that requires clad removal. When the adsorption work is completed, only the filter unit 46 is taken out from the tip portion 16 of the fuel exchanger 12 again by a crane or the like as shown in FIG. 1E. Of course, the collection device 14
The entire unit may be removed and the filter unit 46 may be removed. In this way, the clad 22 is taken out with the filter unit 46 still attached.

The filter unit 46 is directly transferred to the waste repository for storage. The spacer 44 including the pump 40 can be used repeatedly.

The structure of the collecting device used in the present invention is a combination of a spacer having a pump and having a space vertically extending in the center and a filter unit, and a structure such that the shaft of the clad removing wiper can be freely inserted. However, there is no particular structural limitation. However, it is desirable to have a structure in which the once adsorbed clad is less likely to dissipate during use. In that respect, for example, as shown in FIG. 3, a structure in which a suction port is provided on the upper part of the filter unit is preferable. As the filter unit, a rod-shaped or spiral-shaped filter may be used in addition to the one formed in an annular shape.

EFFECTS OF THE INVENTION Since the present invention is a method in which the trapping device is attached to the tip of the fuel exchanger as described above, and the clad which has been peeled off is sucked together with water to be forcibly adsorbed to the filter unit and taken out,
The clad can be efficiently and intensively collected in the vicinity of the generation site without unnecessarily diffusing into the system, and the effect of preventing the expansion of radiation exposure can be obtained.

Further, in the present invention, since an independent device for sucking and collecting the clad is used, it is not necessary to significantly change the existing equipment, and the tip portion of the fuel exchanger is slightly modified so that the collecting device can be attached. It is easy to deal with in a certain degree and is extremely advantageous in terms of cost.

Furthermore, according to the present invention, the clad can be collected at a high density, and since only the filter unit needs to be taken out, the amount of waste generated can be minimized, and the pump, spacer, etc. can be reused, and the waste processing cost can be reduced. It's also cheap.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing an embodiment of a clad collecting method according to the present invention, FIG. 2 is a partial sectional view showing an example of a collecting device suitable for use in the present invention, and FIG. 3 is a plan view thereof. Figure, 4th
The figure is an explanatory view showing the positional relationship between the pressure pipe and the fuel exchanger. 10 …… Pressure pipe, 12 …… Refueling machine, 14 …… Collection device, 16
...... Tip, 18 …… Clad removal wiper, 22 …… Clad, 40 …… Pump, 42 …… Space, 44 …… Spacer,
46 ... Filter unit, 52 ... Suction port.

Claims (1)

[Claims] 1. A spacer having a cylindrical shape having a space extending vertically through a central portion and having a filter unit accommodating space in an upper portion, a filter unit detachable from the filter unit accommodating space above the spacer, and The tip of the fuel exchanger is equipped with a collecting device including a pump attached to the outside of the spacer and pipes connecting the bottom of the filter unit housing space and the pump and the space between the pump and the space at the center of the spacer. Attached to the pressure pipe, moved to the lower end of the pressure pipe, and the clad separated from the pressure pipe surface is sucked together with water by the pump to be adsorbed by the filter unit, and after the adsorption work is completed, it is removed from the tip of the refueling machine. A suction type collection method of the cladding in the pressure pipe, which is characterized in that