JPS6236198B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a handling device used when handling a neutron source holder stored in a fuel pool of a nuclear reactor plant.

Generally, nuclear reactor startup is performed by inserting a neutron source between the reactor core fuel. As neutron sources, those that emit neutrons by causing (γ, n) reaction, (α, n) reaction, and those that emit neutrons by spontaneous nuclear fission are used. and,
When actually installed in the reactor, it is supported by a neutron source holder. A neutron source holder generally houses a plurality of neutron sources in series inside and consists of a cylindrical holder body with one end open, and a weight attached to the other end of the holder body. has been done. Then, it is inserted into the reactor core with the weight side facing down.

By the way, the neutron source holder is worn out and its constituent members become fatigued due to fluid vibrations generated by the flow of coolant (light water) in the core. Therefore, it is necessary to periodically replace it with a new one. Furthermore, the radiation dose of the antimony or other radiation source housed in the holder will attenuate when the reactor operation is stopped for a long period of time, such as for periodic inspections, so it must be replaced with a new one that has not attenuated. There is.

In this way, when replacing the neutron source holder or the neutron source housed in this holder, the neutron source holder is generally removed from the core of the reactor, moved into the fuel pool, and then submerged in the water of this pool. , a method is adopted in which the neutron source holder is processed, or the neutron source inside the holder is extracted and processed. In this case, the operation is extremely difficult due to the remote handling required underwater and the usually thin wall thickness of the holder. For example, if you accidentally drop a neutron source into a pool, it will be nearly impossible to recover it.
In addition, if the neutron source holder is accidentally bent, the neutron source will also bend, causing cracks in the outer cover, and there is a risk that radioactive substances such as Be and Sb used for neutron generation may diffuse into the pool through these cracks. . For this reason, there has been a strong desire for some kind of handling device that can facilitate handling of the neutron source holder and the neutron source.

The present invention has been made in view of the above circumstances, and provides a neutron source that can facilitate the handling of the neutron source holder and the neutron source in a fuel pool, and that can improve safety and workability. An object of the present invention is to provide a holder handling device.

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

First, a neutron source holder that can be handled by the apparatus of the present invention will be explained with reference to FIG.
That is, in the figure, 1 indicates a neutron source holder, and this neutron source holder 1 includes a holder body 2 that can accommodate, for example, two rod-shaped neutron sources P in series, and a A weight 3 is attached to the lower end side and has a larger diameter than the holder main body 2, and a weight 3 is provided protruding from the outer periphery of the end of the holder main body 2 located on the opposite side to the side on which the weight 3 is attached. It is composed of a flange portion 4 and a flange portion 4. The holder main body 2 is formed into a cylindrical shape having a length corresponding to the height of the reactor core, and its upper end in the figure, that is, the end on the side where the flange 4 is provided, is open. Therefore, by inverting the holder body 2 in the opposite direction to that shown in FIG. 1, the neutron source P housed inside can be extracted.

In order to handle the neutron source holder 1 constructed as described above, a handling device according to the present invention is constructed as shown in FIGS. 2 and 3. The configuration of this device will be explained below.

2 and 3, reference numeral 11 is a cylindrical body, and the inner diameter of this cylindrical body 11 is the same as that of the holder main body.
It is set to a value larger than the outer diameter of the weight 3 and smaller than the outer diameter of the weight 3, and its length is set to be slightly shorter than the length of the holder body 2. Said cylinder 1
An auxiliary cylinder 12 is fitted into the lower part of the figure in Figure 1, and by changing the fitting length of this auxiliary cylinder 12, the actual length of the cylinder can be varied. In addition, 13 in the figure connects the auxiliary cylinder 12 to the cylinder 1.
1 shows a screw connected to 1.

A neutron source recovery container 15 is attached to the upper end side of the cylinder 11 in the figure via a connecting member 14. The neutron source recovery container 15 is formed into a cylindrical shape with a bottom, and its opening side faces the upper end opening of the cylindrical body 11. Note that the opening edge of the neutron source recovery container 15 is connected to the connecting member 1.
It is formed in such a manner that its depth becomes shallower as it moves away from 4. on the other hand,
A member 16 is provided at the end of the cylindrical body 11 located on the neutron source collection container 15 side so as to sandwich this end opening.
a, 16b are provided, and these members 16a, 1
6b, the locking levers 17a and 17b are connected to the pin 1.
It is rotatably supported by 8a and 18b. The locking levers 17a, 17b have locking claws 19a, 19b formed at their ends located on the cylindrical body 11 side, which can engage with the flange 4, and also have locking claws 19a, 19b on the outer side bordering the pins 18a, 18b. The portion located at is formed longer than the portion of the locking claws 19a and 19b, and the ends thereof are connected to the wire 20, respectively. Further, the auxiliary cylinder body 12 of the cylinder body 11
on the outer surface of the side where is fitted and the connecting member 1
A hook 21 is protruded from a position opposite to the position where the wire 4 is disposed about the longitudinal axis, and one end of a wire 22 is connected to the hook 21.
Note that 31 in the figure indicates a guide ring attached to the outer surface of the neutron source collection container 15 to guide the wire 20.

Next, using the apparatus configured as described above, the neutron source holder 1 and the neutron source P are placed in the fuel pool.
An example of use when handling will be described with reference to FIGS. 4 to 6.

First, as shown in FIG. 6, the neutron source P is taken out from the neutron source holder 1 temporarily stored in a rack 43 provided in the water 42 of the fuel pool 41, and the neutron source P and neutron source holder 1 are removed. A case will be described in which the fuel and fuel are disposed of separately in the damaged fuel rack 44 provided in the pool 41.

In this case, first, the handler E wearing protective clothing holds the handling device and lifts the auxiliary cylinder from the edge of the pool 41.
The handling device is gradually lowered toward the neutron source holder 1 with the 2 side facing down. Then, the flange 4 side of the neutron source holder 1 is fitted into the cylinder 11, and in this state it is further lowered. Then, from the point when it is lowered to a certain position, it is lowered only by operating the wire 22. When lowered in this manner, the tip of the auxiliary cylinder 12 finally hits the weight 3. When this position is reached, assuming that the fitting degree of the auxiliary cylinder 12 is set appropriately, the collar 4 of the neutron source holder 1 protrudes from the upper end of the cylinder 11 as shown in FIG. state. Therefore, if tension is applied to the wire 20 at this point, the locking levers 17a, 17b will rotate as shown in FIG.
9a and 19b approach each other and engage with the collar portion 4.
This engagement will not be released as long as wire 20 is under tension. Therefore, the neutron source holder 1
will be fully connected to the handling equipment.

When the handling device is lifted using the wire 20, the neutron source holder 1 is also lifted together, so that the neutron source holder 1 is removed from the rack 43 and moved to the pool 41 as shown by X in FIG. Move to a larger location inside.

Next, with the help of handler F, the wire 22 is pulled up as shown by Y in FIG. The neutron source holder 1 is inverted by the . In this way, the neutron source P housed in the neutron source holder 1 slides out, and this neutron source P slides down into the neutron source recovery container 15. Therefore, in this state, use the grip 45 to take out the neutron source P from the container 15, and place the neutron source P in the damaged fuel rack 4.
4, or once stored in the container 46, use the knob 45 to remove the rack 4.
The neutron source P can be disposed of by discarding it within the neutron source P. In addition, in order to discard the neutron source holder 1, first raise the handling device to the state shown by X in FIG. As shown in Fig. 4, the locking lever 1
Since the engagement between 7a and 17b and the collar 4 is released, the neutron source holder 1 can be dropped into the rack 44.

The above explanation is an example of discarding the neutron source holder, but if only the neutron source P is to be converted to a new one, take out the old neutron source P as shown in Y in Figure 6. After that, the handling device is returned to the state shown in FIG. Further, when only the neutron source holder 1 is replaced, the same operation can be performed.

In this way, the neutron source holder can be easily handled only by manipulating the wires, that is, without using compressed air or water pressure as a power source. Therefore, not only can the work be carried out reliably, but also
Since the work can be performed without using other systems such as a working table system, the work can be performed independently of these systems. In addition, since the operation is simple, less manpower is required, and the working time can be shortened, so it can contribute sufficiently in terms of economy and safety. Furthermore, since there is no risk of damaging the neutron source, there is no risk of contaminating the inside of the pool.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of a neutron source holder that is handled by the device of the present invention, FIG. 2 is a front view of the handling device according to an embodiment of the present invention, and FIG.
The figure is a side view of the device, and FIGS. 4 to 6 are diagrams for explaining the operation and usage examples of the device. DESCRIPTION OF SYMBOLS 1... Neutron source holder, 2... Holder main body, 3... Weight, 4... Flange part, 11... Cylindrical body, 12... Auxiliary cylinder body, 1
5... Neutron source collection container, 17a, 17b... Locking lever, 20, 22... Wire, P... Neutron source.

Claims (1)

[Scope of Claims] 1. A cylindrical holder body that accommodates a neutron source inside and has one end open, a flange protruding from the outer periphery of the open end of this holder body, and other parts of the holder body. A cylindrical body that can be fitted to the outer periphery of the holder body of the neutron source holder, which is made of a weight having a larger diameter than the holder body attached to an end side, and that can be fitted only from the flange side of the cylindrical body; and a neutron source recovery container fixed to one end located at the cylinder body so that its opening faces the one-end opening of the cylinder, and connected to a part of the opening edge of the cylinder body; a locking lever rotatably provided on the one end side of the cylindrical body and engaged with the flange of the neutron source holder protruding from the cylindrical body only when tension is applied from the outside; a first wire on which a tension is applied, and one end of which is located on the weight side of the cylindrical body, and the other end thereof is opposed to each other about the longitudinal axis of the connection between the neutron source collection container and the cylindrical body. and a second wire connected to the neutron source holder. 2. The cylindrical body fits and holds an auxiliary cylindrical body having a larger diameter than the cylindrical body on the other end thereof, and by adjusting the fitting position of the auxiliary cylindrical body with respect to the cylindrical body, the axial direction of the auxiliary cylinder is adjusted. The neutron source holder handling device according to claim 1, wherein the length is adjustable.