JPS6239794A - Pool-water purifier in radioactive solid waste storage facility - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pool water purification device in a radioactive solid waste storage facility, and particularly to a pool water purification device that can reduce the amount of secondary waste generated.

[Technical background of the invention and its problems]

Generally speaking, spent fuel channel boxes and other reactor internals are attenuated and stored in a fuel pool, but the number of these reactor internals increases as the power plant operates. Tend.

By the way, the final disposal and treatment methods for these radioactive solid wastes have not yet been established and are under consideration. Therefore, until a specific treatment method is established, a dedicated radioactive storage facility (hereinafter referred to as a site bunker) will be used. It is unavoidable to install and store 1').

This site bunker performs volume reduction treatment when storing radioactive planar solid waste. At this time, the amount of crud attached to the solid waste (rust generated on the surface of the solid waste, rust floating in the air, There is a problem in that debris (debris) peels off, causing a deterioration in the clarity of pool water and an increase in radioactivity concentration in pool water.To prevent this, pool water purification devices have traditionally been installed.

Fig. 5 shows a conventional pool water purification device of this type, in which a site bunker 1 filled with pool water 2 has a non-regenerating (non-backwashing) filter element 3a made of sintered metal. A type 1 filter 3 is installed, and a site bunker pump 5 is connected to the filter 3 via a pipe 4.

The pool water 2 sucked by the site bunker pump 5 is purified by removing crud by a filter 3, and then returned to the site bunker 1 again.

In the conventional boule purification device, the filter 3 is of a non-regenerative type, so as the amount of crud trapped increases, the differential pressure gradually increases, and when this differential pressure exceeds a certain level, the filter element 3a is removed. It is necessary to replace it, and if this is neglected, there is a risk that the capacity of the pump 5 will be exceeded and the outflow of the supplied liquid will decrease. Furthermore, the frequency of replacing the filter element 3a is usually about once every six months, and there is a problem in that the amount of substances generated by the filter element b increases.

In addition, since the filter 3 captures a large amount of crud and increases the radiation dose B, it is installed in the site bunker 1 and uses the pool water as a radiation shielding means, so it is not necessary to maintain the filter element 3a. This requires a remote control device, etc., and there is a problem in that running costs and equipment costs increase.

Therefore, in some cases, instead of the conventional non-regenerative filter 3,
Attempts have been made to install the i-filter outside Site Bankabul 1 by using an auxiliary material backwash type T-filter, but the auxiliary material becomes secondary waste and the amount of secondary waste generated is low. As the amount increases, an auxiliary material feeding device is required, and there is little point in using a backwash type filter.

[Object of the Invention] The present invention has been made in consideration of the above points, so that the filter can be installed outside the site bunker to facilitate maintenance, and moreover, it can reduce the generation of secondary waste. It is an object of the present invention to provide a pool water purification device in a radioactive solid waste storage facility that can reduce the amount of water used.

[Summary of the invention]

The present invention is a pool water purification device for a radioactive solid waste storage facility, which includes a pump that sucks pool water of the radioactive solid waste storage facility, and a pump installed outside the boule that purifies the pool water discharged from the pump. A non-auxiliary backwash type filter that is returned to the boule, a backwash means for this non-auxiliary backwash type filter, a backwash water storage tank that stores backwash water generated by backwashing, and a backwash water storage tank that stores backwash water generated by backwashing. and radiation shielding means for the water storage tank.

(Embodiments of the Invention) A first embodiment of the present invention will be described below with reference to FIG.

In the figure, reference numeral 11 denotes a site bunkerboul filled with pool water 12, and outside of this site bunkerbool 11, there is a non-auxiliary material backwash type tank having a filter element 13a using, for example, a hollow membrane filter. A filter 13 is installed. The pool water 12 is then sucked through a suction line 14 having a site bunker pump 15 and led to a filter 13, where the crud is removed and purified, and then passed through a return line 16 to the site. It has been moved back to Bankabool 1.

The i filter 13 is supplied with station air (SA) 17 for backwashing as shown in FIG.
Clad pipe 1 is connected to the backwash water storage tank 18 installed in 1.
The overflow during backwashing is
The backwash water is supplied to the backwash water storage tank 18 via the overflow pipe 20, and is centrally managed in the backwash water storage tank 18. The overflow and drain from this backwash water storage tank 18 are then fed to an equipment drain 21.

In FIG. 1, reference numeral 22 is condensate water, 23 is a link drain, and 24 is a leak detector.

Next, the operation of this embodiment will be explained.

The crud floating in the pool water 12 is sucked together with the pool water 12 through the suction line 14 by activation of the site bunker pump 15 and guided to the filter 13 .

The pool water 12 purified by the filter 13 is returned to the site bunker 11 via the return pipe 16.

When the amount of crud captured by the filter element 13a of the filter 13 increases and the differential pressure exceeds a certain value, the boule water filtration process is stopped and the house air (SA,
) 17 is supplied to the i-filter 13 to backwash the filter element 13a.

The backwashed crud is sent to the backwash water storage tank 18 via the cladding pipe 19, and the overflow during backwashing is sent to the backwash water storage tank 18 via the overflow pipe 20.

The backwash water is centrally managed in this backwash water storage tank 18. The drain and overflow of the backwash water storage tank 18 is
It is fed to the equipment drain 21.

In this way, since the γ filter 13 is a backwash type, the radiation dose does not increase unlike a non-backwash type, and therefore it can be installed outside the site bunker 11. Therefore, maintenance is easy and running costs can be reduced.

Furthermore, since the filter 13 is of a non-auxiliary material type, the amount of secondary waste generated can be reduced.

In addition, the backwash water storage tank 18 that centrally manages the cladding is installed in the site bunker 11 and is shielded by the pool water 12 with a high shielding effect, so there is no need for a special radiation shielding wall, and the building can be used effectively, and the burden @m of work q can be reduced.

Note that if a radiation shielding wall can be installed for the backwash water storage tank 18, the backwash water storage tank 18 may be installed outside the site bunker 11 as shown in FIG.

FIG. 3 shows a second practical example of the present invention.
2, the electrical conductivity can be adjusted.

That is, while the crud in the boule water 12 is removed, a demineralization tower 25 filled with an ion exchange resin 25a is connected to the exit side of the strainer 13 via a return pipe 16, as shown in FIG. The pool water 12 desalinated in the desalination tower 25 is returned to the site bunker 11 via a return pipe 26.

As shown in FIG. 3, the demineralization tower 25 is supplied with internal air (
SA) 17 has been introduced, and
New ion exchange resin is introduced through a new resin transfer pipe 27, and used ion exchange resin is discharged into a used resin storage tank 29 via a pipe 28. It has become. Regarding other points, please refer to the above 1.
It is exactly the same as the example.

In this way, since the pool water 12 purified by the filter 13 is led to the demineralization tower 25 for desalination, the electrical conductivity of the pool water 12 can be adjusted.

Note that the desalination tower 25 basically only needs to be used when the electrical conductivity of the pool water 12 increases. For this reason, a bypass pipe is provided in the desalination tower 25, and the pool water 1 is used only when necessary.
2 may be passed through a desalting tower 25.

FIG. 4 shows a third embodiment of the present invention, in which the filter 13
A heat exchanger 30 using cooling water 31 is installed on the inlet side of the second embodiment, and other points are completely the same as the first embodiment.

By installing the heat exchanger 30 in this manner, spent fuel can also be stored in the same manner as FPC.

However, when storing spent fuel, the filter 13
It is preferable to install a desalination tower on the outlet side of the pool water 12 to adjust the conductivity of the pool water 12.

In each of the above embodiments, a hollow membrane filter is used as the filter element 13a of the i-filter 13, but other filters may be used as long as they are non-auxiliary backwash filters.

In addition, the backwash water storage tank of the backwash type filter used in systems where other radioactive materials flow can be installed in the site bunker pool or equivalent equipment, and the same effect can be obtained. is obtained.

〔Effect of the invention〕

As explained above, the present invention uses a non-auxiliary material backwash type filter as a filter to remove crud from pool water and purify the pool water, so the filter can be installed outside the pool. can. Therefore, maintenance is easy and running costs can be reduced. Furthermore, since the filter itself or its auxiliary materials do not become secondary waste, the amount of secondary waste generated can be reduced.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing a first embodiment of the present invention, Fig. 2 is a system diagram showing a modification thereof, Fig. 3 is a system diagram showing a second embodiment of the invention, and Fig. 4 is a system diagram showing a modification thereof. FIG. 5 is a system diagram showing a conventional pool water purification device. 11... Site banker pool, 12... Pool water,
13... filter, 13a... filter element, 15... site bunker pump, 18... backwash water storage tank, 25... desalination tower, 31... heat exchanger. Applicant's agent Sato - Ite 1st item 2nd item 3@

Claims (1)

[Claims] 1. A pump that sucks pool water in a radioactive solid waste storage facility, and a non-auxiliary backwash filtration installed outside the pool that purifies the pool water discharged from the pump and returns it to the pool. a backwashing means for the non-auxiliary material backwashing type filter, a backwashing water storage tank for storing backwashing water generated by backwashing, and a radiation shielding means for the backwashing water storage tank. A pool water purification device in a radioactive solid waste storage facility, characterized by: 2. A pool water purification device in a radioactive solid waste storage facility according to claim 1, characterized in that a backwash water storage tank is disposed within the pool to use the pool water as radiation shielding means.