JPS6238679B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and apparatus for storing a nuclear fuel assembly in a container in a storage water tank and collecting a cooling water sample to immerse the nuclear fuel assembly in order to detect abnormalities in the nuclear fuel assembly. Regarding.

Nuclear fuel assemblies installed in the core of a nuclear reactor are at risk of being damaged due to long-term use or due to some unexpected cause. The cooling water inside the container is extracted and used as a sample to detect whether there is an abnormality in the nuclear fuel assembly.

A conventional method and apparatus for collecting a cooling water sample for nuclear fuel assembly abnormality detection will be described with reference to FIG.

The hollow container 2 into which the nuclear fuel assembly 1 to be inspected for abnormalities is inserted is placed vertically in the cooling water 4 below the water surface 5 with its lower end pedestal in contact with the tank bottom of the storage tank 3. . A substantially U-shaped arm 8 is rotatably supported by a pair of pin shafts 7 horizontally fixed to the upper open cylindrical portion 6 of the container 2 at both legs of the lower end thereof. . An eye bolt 9 is screwed onto the upper side of the arm 8. The arm 8 has a positioning pin 11 whose lower end protrusion 10 is fixed to the cylindrical part 6.
vertically when engaged with the other locating pin 1 fixed to the cylindrical part 6.
When engaged with 2, it becomes almost horizontal. Opening/closing lid 13
is connected to the cylindrical part 6 by a hinge 14 so as to be openable and closable, and by closing the opening/closing lid 13 and turning the vertical eye bolt 9, the lower end surface of the container is brought into close contact with the upper end surface of the cylindrical part 6 in a watertight manner. Seal 2. Inside the container 2, there is cooling water 4 in a storage water tank 3.
is fulfilled. Conduit 1 is located at the bottom of container 2.
5 is connected to the upper end of the opening/closing lid 13, and is connected to a conduit 16 which can be bent near the connecting part thereof, and the conduit 16 is connected to the conduit 15 via an electric pump 17 and an on-off valve 18. There is. The pipe line between the electric pump 17 and the on-off valve 18 is branched, and the branch pipe is connected to the on-off valve 1.
9, and the outlet side of the on-off valve 19 is connected to a cooling water sample collection conduit 22.

To insert the nuclear fuel assembly 1 into the container 2, first open the lid 13. for that purpose,
An operating rod (not shown) having a hook at the tip is visually hooked onto the eye bolt 9 in the cooling water 4, the eye bolt 9 is turned, the opening/closing lid 13 is untightened, and the eye bolt 9 is folded horizontally together with the arm 8.
Subsequently, the opening/closing lid 13 is opened using the same operating rod. In this state, the nuclear fuel assembly 1 is inserted into the container 2 by appropriate means. The nuclear fuel assembly 1 is
The lower end stopper 20 is positioned vertically in the container 2 with its upper outer periphery positioned on a conical seat 21 at the lower part of the container 2 by a positioning member (not shown) and with its outer periphery separated from the inner wall of the container 2.
In this state, the opening/closing lid 13 is closed using the operating rod in the same manner as described above, and the eye bolt 9, which has been returned to the upright position along with the arm 8, is screwed in to seal the container 2. Subsequently, when the on-off valve 19 is closed and the on-off valve 18 is opened and the electric pump 17 is operated, the cooling water in the container 2 is circulated. After this state continues for a certain period of time, the electric pump 17 is stopped, the on-off valve 18 is closed, and the on-off valve 1 is closed.
9, a cooling water sample can be collected via the cooling water sampling conduit 22. Once the required amount of cooling water sample has been collected, the on-off valve 19 is closed.

In the conventional method and apparatus, cooling water 4
The operations on the internal parts are all carried out manually by a worker who is positioned on the floor above the side wall of the storage water tank 3 and visually observes them, which requires a lot of time. There is a risk of being exposed to radiation from the nuclear fuel assembly 1, and there are also drawbacks such as difficulty in visual observation if there are ripples or light reflections on the cooling water surface 5.

This invention was made to eliminate the drawbacks of the conventional methods and devices, and is a method for collecting cooling water samples in which all operations are automated by remote control after a nuclear fuel assembly is inserted into a container. and its equipment.

An embodiment of the present invention will be described with reference to FIGS. 2 to 4. Here, parts given the same reference numerals as in FIG. 1 are completely the same as those in FIG. 1, and therefore will not be described again.

The hollow container 2a has its lower end pedestal in contact with the tank bottom of the storage water tank 3, and its water surface 5 is in contact with the cooling water 4.
It is placed vertically at the bottom. The upper peripheral wall of the container 2a has a cylindrical part 6a with an open top extending outward, and a positioning plate 25 that can position the nuclear fuel assembly 1 in the center hole is integrally attached to the bottom of the cylindrical part 6a. It is being Cylindrical part 6
A protruding arm 26 is integrally formed on the outer wall of a, and a hinge pin 27 is provided at the upper outer end of the protruding arm 26.
is fitted horizontally. An O-ring 28 is housed in the annular upper end surface of the cylindrical portion 6a. A conical seat 21 is formed at the center of the lower end of the container 2a, and the nuclear fuel assembly 1 inserted into the container 2 is placed approximately at the center of the container 2 on its outer surface by the conical seat 21 and the positioning plate 25. A space filled with cooling water 4 exists between the container 2 and the inner wall of the container 2, and the container 2 is held upright. The opening/closing lid 13a, whose outer wall is the same as the outer wall of the cylindrical portion 6a and whose upper surface is closed, is rotatably supported on a hinge pin 27 at the outer lower end of its protruding arm 29, and its lower end surface is supported by an O-ring 28. It can be brought into close contact with the upper end surface of the cylindrical portion 6a via the cylindrical portion 6a. Furthermore, a protruding base 31 having a horizontal pin shaft 30 at its upper end is integrally formed on the upper end surface of the opening/closing lid 13a. A lever 32 is rotatably supported on the pin shaft 30 at its center, the left end of the lever 32 is rotatably supported on the upper end of a piston rod 34 of a pneumatic cylinder 33, and the right end of the lever 32 is rotatably supported on the pin shaft 30. A lid holder 35 having a pad at its lower end is rotatably supported at its upper end. Pneumatic cylinder 33
The lower end of the cylinder is rotatably supported by the tip of a protruding arm 36 that protrudes integrally from the outer wall of the container 2a. Both upper and lower ends of the cylinder portion of the pneumatic cylinder 33 are connected to a four-way electromagnetic switching valve 37 via pipes, and the other two roads of the electromagnetic switching valve 37 are connected to an open pipe 38 and a compressed air supply pipe, respectively. A pressure gauge 40 and a pressure reducing valve 41 are connected to the pipe line 39 . A conduit 15a is connected to the bottom of the container 2a, a drain valve 42 is provided at the lowest part thereof, and a conduit 16a is connected to the upper end of the opening/closing lid 13a. The near part can be bent. Connected in series to the conduit 16a are an electric pump 17a that can be controlled in conjunction with a timer 43, a flow rate adjustment valve 44, and an electromagnetic on-off valve 18a, and the outlet of the electromagnetic on-off valve 18a is connected to the conduit 15a. There is. Flow rate adjustment valve 44 and electromagnetic opening/closing valve 1
The pipe connecting 8a branches, and this branch pipe is connected to an electromagnetic on-off valve 19a controlled by a timer 45, and the outlet of the electromagnetic on-off valve 19a is connected to a cooling water sample collection pipe 22. There is. Electromagnetic switching valve 37, pressure gauge 40, pressure reducing valve 41, electric pump 17a, timers 43, 45, flow rate adjustment valve 44, electromagnetic on-off valve 18
19a and 19a are both installed at a position away from the storage liquid tank 3, and except for the pressure gauge 40, the pressure reducing valve 41, and the flow rate adjustment valve 44, all of them are controlled individually through a separate centralized electromagnetic control panel (not shown) with a known configuration. It is now possible to remotely control the sequence.

The operation of the apparatus of the present invention constructed as described above will be described below.

Checking the indication on the pressure gauge 40, the pressure reducing valve 41
Adjust the pressure of the compressed air supply to the desired level.
When the electromagnetic switching valve 37 is biased to one side, compressed air is sent to the upper end of the cylinder portion of the pneumatic cylinder 33, and its piston rod 34 is lowered, thereby,
Through the lever 32, the lid holder 35 opens and closes the lid 13a.
is released, and then the pneumatic cylinder 33 is rotated counterclockwise around the pin shaft provided at the tip of the protruding arm 36, so that the opening/closing lid 13a is rotated counterclockwise.
is rotated counterclockwise around the hinge pin 27 to open, and the top surface of the container 2a is opened. In this state, if the nuclear fuel assembly 1 is lowered into the container 2a by conventionally known means, the nuclear fuel assembly 1
The lower end plug 20 is positioned in the lower conical seat 21 of the container 2a, and the upper outer periphery is positioned in the inner hole of the positioning plate 25.
It is placed upright inside. Next, solenoid switching valve 3
7 is energized in the opposite direction, compressed air is sent to the lower part of the pneumatic cylinder 33, the piston rod 34 rises, and the piston rod 34 follows the opposite direction path to the previous case in which it descended. The opening/closing lid 13a is closed,
The lid holder 35 connects the opening/closing lid 13 via the O-ring 28.
A is pressed against the top of the opening of the container 2a in a watertight manner.

As the electromagnetic switching valve 37 is biased in the reverse direction, an electric signal (hereinafter simply referred to as a signal) S is sent from the electromagnetic control panel.
1 is sent to the electromagnetic on-off valve 18a, and the electromagnetic on-off valve 18a
opens. At this time, the electromagnetic on-off valve 19a remains closed. With the opening operation of the electromagnetic on-off valve 18a, a signal S2 is issued, and in response to this, the electric pump 17
a starts. If the electric pump 17a operates,
The cooling water in the container 2a is supplied to the flow rate regulating valve 44 in advance.
With the flow rate set in
a, circulates through the pipe 15a. When the time preset in the timer 43 has elapsed, the electric pump 17a is stopped by the signal S3, and the emitted signal S4 is stopped.
In response, the electromagnetic on-off valve 18a closes, and the electromagnetic on-off valve 1
9a is open so that cooling water flows down through the conduit 22 and a cooling water sample can be taken at its lower tube end. When the time preset in the timer 45 has elapsed since the electromagnetic on-off valve 19a opened, the timer 45 emits a signal S5, and the electromagnetic on-off valve 19a closes upon receiving the signal S5. The switching valve 37 receives the signal S6 issued from the timer 45 at the same time as the signal S5, and the pneumatic cylinder 33
Switching to supply compressed air to the upper part of the cylinder, the opening/closing lid 13a is opened in the same manner as described above, the nuclear fuel assembly 1 is taken out from the container 2a, and the next nuclear fuel assembly to be inspected is placed in the container 2a. It's ready to be inserted into.

As described in detail in the above embodiments, the device of the present invention includes a container that is placed in cooling water in a storage water tank and has an open top surface into which a nuclear fuel assembly can be inserted upright, and a container that has the open top surface of the container sealed. A pneumatic cylinder that opens and closes the lid by remote control and simultaneously performs the sealing operation and opening/closing operation of the lid in the cooling water in the storage water tank; A circulation pipe for cooling water inside the container, one end of which is connected to the upper end and one end of the lower end. a remote-controlled circulation device that circulates the water; a branch pipe that branches from the circulation pipe and communicates with an on-off valve that can be opened and closed by remote control, through which cooling water circulated from inside the container by the circulation device flows; When using the apparatus of the present invention and the method of the present invention, after inserting the nuclear fuel assembly to be inspected into the container, cooling water is All operations can be performed automatically by remote control until the sample is collected, compared to the conventional case where the operator is located on the upper floor of the side wall of the storage tank and manually performs the work while visually observing the sample. The work time is significantly shortened, and since the operation is performed by remote control, the degree of radiation exposure is also significantly reduced and the work can be carried out safely and reliably.

Furthermore, an air cylinder using air as the driving source of the cylinder is used as the driving force for the opening/closing operation of the opening/closing lid in the cooling water in the storage water tank and the tight sealing operation of the closed lid, so that the opening/closing operation in the cooling water, etc. Even if an air leak occurs in the compressed air supply pipe (hose) during the work, this air leak forms bubbles in the water and can be easily observed by the worker on the surface of the water. Therefore, malfunctions in the device can be detected early, reliably, and without incurring any cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional cooling water sample collection device for detecting abnormalities in nuclear fuel assemblies, FIG. 2 is a block diagram of the device of the present invention, FIG. 3 is a plan view of essential parts of the device of the present invention, and FIG. The figure is a block diagram showing the operating sequence of the apparatus of the present invention. 1...Nuclear fuel assembly, 2a...Container, 3...
...Storage tank, 4...Cooling water, 13a...Opening/closing lid,
15a, 16a...pipe line, 17a...electric pump, 18a, 19a...electromagnetic on-off valve, 22...cooling water sample collection pipe line, 33...pneumatic cylinder.

Claims (1)

[Claims] 1. A container that is placed in cooling water in a storage tank and has an open top surface into which a nuclear fuel assembly can be inserted upright; a lid that can be opened and closed to seal the top surface of the opening; a pneumatic cylinder that opens and closes the opening/closing lid by remote control and simultaneously seals the opening/closing lid and opens and closes the lid in cooling water in a storage water tank; and a container having one end connected to the upper end and the lower end of the container, respectively. an internal cooling water circulation pipe; and a remote-controlled circulation device provided in the circulation pipe, which circulates the container cooling water within the ring pipe and the container for a certain period of time set by a timer. and a branch pipe branching from the circulation pipe and communicating with an on-off valve that can be opened and closed by remote control, through which cooling water previously circulated from within the container by the circulation device flows, and each of the above-mentioned controls. A cooling water sample collection device for nuclear fuel assembly abnormality detection, comprising a sequence control device capable of sequence control.