JPH11352280A - Spent fuel pool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure and maintenance operation by allowing a replenishment water tank to have the functions of a skimmer surge tank, a replenishment water tank, and a buffer tank, and at the same time providing a purification device in the water bath. SOLUTION: Pool water 2 from a spent fuel pool 15 is cooled by a heat exchanger 11 through heat exchanging with cooling water 12 and is reflowed back to the spent fuel pool 15 by a pool water transfer pump 5, via a replenishment water tank 16 and pool water piping 4. In this case, the pool water 2 overflowing into the replenishment water tank 16 is divided and flows into a plurality of purifying channels of a purification device 18. The pool water 2 passes through the layer of a purification filter medium 22, being arranged at the upper portion of a lattice plate 21 in the channel and is then purified. In this case since, the purification channel are formed in plurality and each can be operated independently, so that another system can ensure functions, even if some channels fail. Also, since the open-to-atmosphere type is used, the opening/closing operation of a lid is eliminated, when exchanging the purification filter medium 22, so that maintenance is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spent fuel pool attached to a nuclear reactor for storing spent fuel or installed independently of the nuclear reactor.

[0002]

2. Description of the Related Art In a conventional nuclear power plant, a fuel pool for storing and cooling spent fuel is installed in addition to a nuclear reactor that generates steam for power generation. A dedicated spent fuel storage pool is also used to store spent fuel for temporary storage until it is separately transferred to a reprocessing facility. Call.

In these fuel pools, in order to cool decay heat from spent fuel, water cooled in advance by seawater or air is stored as pool water and circulated in the fuel pool. For this purpose, a skimmer surge tank having a function of maintaining a constant amount of water in the fuel pool, that is, the pool water level, is installed adjacent to the fuel pool, and receives excess pool water in the fuel pool. I have.

On the other hand, pool water lost due to evaporation or the like can be replenished from the water surface of the fuel pool at any time.
A makeup water tank is separately installed. In the fuel pool, the spent fuel stored by these pool waters is cooled in order to always keep the temperature below a certain temperature, but this pool water also serves to shield radiation from the spent fuel. It is managed so that the water quality is always maintained at a certain level simultaneously with cooling.

[0005] Therefore, a purifying device having a filtering and desalting function is connected to the fuel pool, and the purifying device is provided with a filtering device and a desalinating device or a filtering and desalinating device having both functions. However, hereinafter, it is referred to as a filtration desalter unless the function is particularly limited. Further, the apparatus is provided with a transfer pump for the pool water, piping and valves for connecting the pumps, and a control device for operating the equipment. In addition, a resin filter, a hollow fiber membrane filter, or the like is used as a purification filter in the filtration desalter.

[0006] In these filter desalters, the purifying filter used for filtering the pool water is periodically replaced to maintain the filtering capacity so as to always satisfy a certain standard. The replacement of the filter is usually performed about once a year. At this time, the filter and desalinator is once opened to replace a part or the entire amount of the internal purification medium. Also,
Regarding the filter desalter, filtration is performed so that pool water circulating in the fuel pool passes at a constant pressure, and for this reason, the main body of the filter desalinator is maintained at a constant pressure. It has a robust structure to withstand.

For this reason, opening and reassembling operations of the filter desalter require separation of the filter desalter from the purification system, opening and closing of the lid, and carrying in and out of the filter material. And it takes time. Further, the filter desalter collects the fine radioactive powder clad, which is an impurity in the water, by purifying the pool water, whereby the radiation amount of the purifying filter material increases.

[0008] Therefore, during the normal operation of the filter desalinator, the backwashing or discharging operation of the purified filter medium is performed periodically.
The cladding captured by the purification filter is discharged to a solid radioactive waste receiving tank. When the purification filter is a hollow fiber membrane type filter such as a hollow fiber membrane filter and is fixed in the filter, the clad is discharged to the solid radioactive waste receiving tank by itself, but the filter is desalinated. In the case of a resin filter that also functions as a resin, the clad is discharged together with the purification resin into a tank that receives the solid radioactive waste.

FIG. 6 shows a system configuration diagram of a fuel pool and a purification system thereof. The fuel pool 1 is installed adjacent to a reactor (not shown), and stores pool water 2 therein. The new fuel (not shown) to be newly loaded into the reactor and the spent fuel removed from the reactor are temporarily stored in the water.

A skimmer surge tank 3 is provided adjacent to and communicates with the fuel pool 1, and the skimmer surge tank 3 circulates pool water 2 from a pool water pipe 4 by a pool water transfer pump 5. In this case, a function of a buffer tank for storing pool water 2 overflowing 6 from the fuel pool 1 is provided.

[0011] Further, downstream of the pool water transfer pump 5 connected to the skimmer surge tank 3 and the pool water pipe 4, there is provided a filter desalination device which is a device for purifying the pool water 2 in the fuel pool 1. 7 are installed. When the filtration and desalination unit 7 is a resin type of resin filter, the pool water 2
And a new resin supply tank 8 for supplying a new purification resin necessary for purifying the resin.

Regardless of whether the filter desalter 7 is a resin type or a hollow fiber type, the solid radioactive waste receiver for discharging the clad in the pool water 2 collected by the filter desalter 7 is used. A tank 9 is provided. In the case where the filtration desalter 7 is a hollow fiber membrane filter of a hollow fiber membrane type, a backwash water supply facility (not shown) for supplying backwash water 10 used for backwashing the purification filter medium is also provided. ing.

Further, the temperature of the pool water 2 rises due to the decay heat released from the spent fuel.
This must be cooled below a certain level, and a heat exchanger 11 as a cooling device for this cooling is installed in the circulation system of the pool water 2. Therefore, this heat exchanger 11 is supplied with cooling water 12 cooled by seawater or outside air, and purified and cooled by the filter desalinator 7 and the heat exchanger 11, and the cooled pool water 2 It returns to the fuel pool 1 again.

Thus, the pool water 2 in the fuel pool 1
Is constantly circulated, but part of the water is gradually lost from the water surface 1a of the fuel pool 1 due to evaporation or the like. Therefore, it is necessary to replenish the lost pool water 2 from the makeup water tank 13 as necessary. . This makeup water is separately supplied from the makeup water tank 13 by the makeup water transfer pump 14 to the fuel pool 1.
Supplied to

As described above, in the conventional nuclear power plant, both the skimmer surge tank 3 and the make-up water tank 13 are provided for the fuel pool 1, and the amount of water retained in these tanks is enormous. For this reason, the size of the building where these tanks are installed is also required.

[0016]

In the conventional nuclear power plant, the fuel pool 1, the skimmer surge tank 3, and the makeup water tank 13 are separately installed. However, there has been a problem that the cost of manufacturing equipment and installation locations also increases.

In the purification system, since the filtration and desalination unit 7 which is directly involved in the purification of the pool water 2 has a closed structure, when the filtration medium contained therein is exchanged, the container of the filtration and desalination unit 7 is replaced. These operations are performed manually by workers due to the nature of the operations. Therefore, there is a problem that a great deal of labor and time are required for the operation related to the operation of the purification system of the pool water 2.

Further, when the purifying means is a resin-type filter and desalter 7, a supply operation of a new purifying resin and a discharging operation of a used purifying resin are required.
Also, the system and the equipment configuration, such as a transfer pump and piping, not shown, and a switching valve and a control device, are complicated, and there is a disadvantage that maintenance is complicated along with assembly.

An object of the present invention is to provide a replenishing water tank provided with a spent fuel pool with the functions of a skimmer surge tank, a replenishing water tank and a buffer tank, and a spent fuel tank provided with a purifying device therein. It is to provide a fuel pool.

[0020]

According to a first aspect of the present invention, there is provided a spent fuel pool for storing and cooling spent fuel taken out of a nuclear reactor. It is characterized in that the water level of the pool is maintained constant by communicating with the spent fuel pool, and a makeup water tank provided with a purifying device is provided inside.

The pool water stored in the spent fuel pool storing the spent fuel overflows to a makeup water tank communicating with the pool water in accordance with the rise in the water level, thereby maintaining the pool water level constant. The pool water overflowed at this time is purified by a purifying device provided inside the makeup water tank.

A spent fuel pool according to a second aspect of the present invention is characterized in that, in the first aspect, the makeup water tank is integrated near the spent fuel pool. Since the makeup water tank is integrated adjacent to the vicinity of the spent fuel pool, the communication path is short and the installation place is easy to secure.

A spent fuel pool according to a third aspect of the present invention is characterized in that, in the first or second aspect, the purification device is formed by arranging a plurality of purification passages in parallel.
The purifying device provided in the makeup water tank is divided into a plurality by a plurality of parallel purification channels formed in the makeup water tank, and performs a purification process in each purification channel.

According to a fourth aspect of the present invention, in the spent fuel pool according to the third aspect, the plurality of purification passages in the purification device can be operated independently by opening and closing each purification passage. . By removing and attaching a dropping door or the like provided in each purification channel, the purification channel can be opened and closed, and the operation and stop adjustment of the purification function divided for each purification channel can be performed.

According to a fifth aspect of the present invention, in the spent fuel pool according to the third aspect, the purification device stores the purification resin in each of the purification channels in a flexible container having a mesh size through which impurities can pass. Characterized in that at least one or more purifying filter media are arranged. A purifying resin is accommodated in a flexible and permeable container such as a mesh bag as a purifying filter, and at least one purifying filter is disposed in the purifying flow path, and pool water is provided in the purifying flow path. To purify.

[0026] The spent fuel pool according to the invention of claim 6 is characterized in that, in claim 3, the purifying device is arranged such that containers of purifying filter media are closely arranged in the purifying flow path in the horizontal direction and the vertical direction. . By arranging the containers of the purification resin in a horizontal direction and a vertical direction in the purification flow path and forming a shape having no gap between each other, for example, a rectangular shape, a short path is prevented, and a hollow in addition to the purification resin is formed. A thread membrane or the like can also be employed.

A spent fuel pool according to a seventh aspect of the present invention is characterized in that, in the first aspect, the purification device maintains the pool water to be released to the atmosphere and purified at a hydrostatic pressure.
Since a large pressure is not applied to the purification filter medium of the purification device, the mechanical strength of the purification system including the container can be reduced, and the structure is simple and the maintainability is improved.

According to an eighth aspect of the present invention, in the spent fuel pool according to the seventh aspect, the purifying device is characterized in that a structural part opened to the atmosphere is a place for carrying in and out the purifying filter medium. Since the water surface of the makeup water tank is open at the upper part of the purifying device, it is possible to easily carry in and out the purifying filter medium from this opening at any time.

A ninth aspect of the present invention provides the spent fuel pool according to the third aspect, wherein the spent fuel pool is conveyed by covering the periphery of the purification filter medium with a shielding cover when replacing the purification filter medium. . At the time of replacement of the purification filter medium, by covering the periphery of the purification filter medium taken out of the purification device with the shielding cover, it is possible to reduce the exposure of the worker during transportation.

According to a tenth aspect of the present invention, there is provided the spent fuel pool according to the first aspect, wherein the pool water in the spent fuel pool is re-used through the purification device and the cooling device. The circulatory system returning to the pool is one system. In the spent fuel pool, when the spent fuel that has been cooled to a certain extent in the fuel pool attached to the nuclear reactor in advance has been transferred, the pool water is not always circulated due to the amount of storage and heat generation. Since there is no need for cooling, the pool water transfer pump is not duplicated,
There is no hindrance by repairing immediately after a failure.

[0031] In the spent fuel pool according to the invention described in claim 11, the spent fuel pool according to claim 1 divides a cooling device provided in a pool water circulation system into a plurality of unit cooling devices effectively. Then, the number of operating unit cooling units is changed according to a rise in the temperature of the pool water.
For the cooling capacity required for the amount of spent fuel stored and the amount of heat generated in the spent fuel pool, one or more unit cooling devices that are divided into multiple units according to the required cooling capacity are installed sequentially. Operation increases the efficiency of equipment and operation.

According to a twelfth aspect of the present invention, there is provided the spent fuel pool according to the first aspect, wherein the spent fuel pool monitors the water quality of the pool water online and adjusts the operation of the purification function according to the degree of water quality reduction. It is characterized by doing. The quality of the pool water in the spent fuel pool is monitored online, and the multiple purification channels in the purification device are appropriately opened and closed according to the degree of water quality degradation, so that the operation of the purification function is adjusted and the appropriate water quality is constantly maintained. maintain.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described related art are denoted by the same reference numerals, and detailed description thereof will be omitted. The first embodiment relates to claims 1 to 5, claim 7 to claim 10, and claim 12.

As shown in the system configuration diagram of FIG. 1, a spent fuel pool 15 in a nuclear power plant is integrally provided with a make-up water tank 16 which is adjacent to and communicates with a pool water surface 15a. About the spent fuel pool
It has the function of the conventional skimmer surge tank 3 for keeping the pool water level 15a constant at 15, and the function of the make-up water tank 13 as the volume of the predetermined water holding amount.

That is, in the makeup water tank 16, the amount of water required for the conventional makeup water tank 13 is secured in the upper water storage section 17 a and the lower water storage section 17 b, and the spent fuel pool 15 is stored.
In addition to a function as a buffer tank for circulating the pool water 2 and a skimmer surge tank in which the pool water 2 stored in the pool overflows 6, a purification device 18 as a purification system is built in. .

As shown in the perspective view of the main part of FIG. 2, the purifying device 18 is located below the water surface 16a of the replenishing water tank 16 and almost at the middle thereof. Department
The lower reservoir 17b below the purifier 17a and the purifier 18 also serves as a reservoir. The pool water pipe 4 is connected to the bottom of the makeup water tank 16, and the pool water transfer pump 5 and the heat exchanger
The purified and cooled pool water 2 is returned to the spent fuel pool 15 through one system of the purified and cooled circulation path via the eleventh line (claim 10).

Further, the purification device 18 forms a plurality of purification passages 20 which are divided in parallel by vertically dividing a plurality of partition plates 19 from the upper portion of the makeup water tank 16 to a substantially middle portion thereof. A lattice plate 21 serving as a flow path is provided at the bottom, and a purification filter 22 is disposed above the lattice plate 21 to form a filtration layer 23 (claim 3).

Further, a makeup water tank of the spent fuel pool 15
At the communication part with the pool 16, in order to keep the height of the water surface 15 a of the pool water 2 stored in the spent fuel pool 15 constant, the pool near the water surface 15 a from the communication part in accordance with the rise of the water surface 15 a A weir 24 is provided to allow a part of the water 2 to overflow 6 to the makeup water tank 16. In addition, the weir 24 is provided with a dropping door 25 for detachably closing each of the purification passages 20 by closing an upper part thereof.

Therefore, a plurality of purification channels 20 formed inside the makeup water tank 16 are provided in each of the purification channels 20 by the weir.
The purifying function is divided into a plurality of parts by attaching / detaching the dropping doors 25 at 24, and each of them can be operated independently (claim 4). Further, a grid plate is provided in each purification passage 20.
The purifying filter medium 22 disposed on the upper part of the resin filter 22 is a resin type of a resin filter, the mesh has a size that allows impurities to pass therethrough, and a flexible container, for example, containing an appropriate amount of the purifying resin in a mesh bag and configured. One or more purifying filter media 22 are arranged in accordance with the purifying amount (claim 5).

The upper surface of the replenishing water tank 16 is opened in the same manner as the fuel pool 15 so as to be open to the atmosphere, so that the pressure applied to the purification filter medium 22 by the pool water 2 to be purified becomes a hydrostatic pressure. The open portion on the upper surface serves as a carry-in / out place for the plurality of purification filter media 22 in the purification device 18 (claims 7 and 8). When carrying out the purifying filter medium 22 in the purifying device 18 in the replenishing water tank 16, as shown in the side view of the purifying filter medium transport shown in FIG. Is attached.

Further, a transport device for carrying in and out the purifying filter medium 22 includes, for example, a chain block or a hoist 27.
However, a transparent shielding cover 30 is attached to a hanging rope or the like in the vicinity of the hanging member 28 so as to be vertically slidable by a hanging string 29, and the purifying filter medium 22 is stored in the inside. And transported out (claim 9). In the pool water 2 circulating through the spent fuel pool 15,
The water quality is monitored online, and when the water quality falls below the set value, the pool water transfer pump 5 is operated to control the water purification (claim 12).

Next, the operation of the above configuration will be described. In the fuel pool 16 in the spent fuel pool 15 shown in FIG. 1 and FIG. 2 in which spent fuel (not shown) is stored, the pool water 2 circulating therein rises in temperature by cooling the spent fuel, and The cladding of minute radioactive powder separated from the surface of the spent fuel is mixed as impurities.

The pool water 2 is cooled from the spent fuel pool 15 through the makeup water tank 16 and the pool water pipe 4, and is operated by the pool water transfer pump 5 to exchange heat with the cooling water 12 in the heat exchanger 11. Then, it is returned to the spent fuel pool 15. At this time, as the water surface 15a in the spent fuel pool 15 rises, a part of the pool water 2 overflows 6 from the weir 24 to the make-up water tank 16, and the pool water 2 that has overflowed 6 in the make-up water tank 16 The water is divided into a plurality of purification channels 20, which are purification devices 18, which are partitioned by a partition plate 19, and flow therethrough.

In each of the purification channels 20, a plurality of purification filter media 22 containing a purification resin in a mesh bag, which is a flexible container, are arranged above the lattice plate 21, whereby the filtration layer 23 is formed. Since it is formed, the pool water 2 passing through this filtration layer 23
The cladding of radioactive powder, which is a mixed impurity,
It is purified by being captured in the purification filter medium 22. In this purifying apparatus 18, the pool water 2 passing therethrough is generally made thicker by increasing the thickness of the filtration layer 23 compared to the cross-sectional area of the flow path formed by the purifying filter medium 22.
Since the time for touching is increased, the purification effect is improved.

Further, in the plurality of purification channels 20, which are the purification devices 18 of the make-up water tank 16, the spent fuel pool 15 and the spent fuel pool 15 are changed in accordance with the purification processing amount of the pool water 2 and the replacement work of the purification filter material 22. By installing the drop door 25 in the communication passage of
The overflow 6 of the pool water 2 to the purification channel 20
And the purifying function in the purifying flow path 20 can be stopped alone.

Accordingly, by appropriately attaching and detaching the dropping doors 25 in accordance with an increase or decrease in the purification processing amount of the pool water 2, the purification processing capacity of the purification device 18 is appropriately adjusted,
As for the purifying device 18 and the purifying filter medium 22, the operation efficiency with the purifying treatment efficiency is improved, and the maintenance efficiency such as the replacement work is improved together with the life of the purifying filter medium 22.

In the purifying apparatus 18, since the purifying flow path 20 is constituted by a plurality of systems and each can be operated independently, if only one system is used,
If for some reason the filter layer becomes unusable and it becomes necessary to restore it, the purification channel having only one system will be closed.

As a result, the purification function is completely lost in the purification system until the filtration layer is restored, which hinders the operation of the spent fuel pool. Of the purification flow path 20 of FIG. In this way, even if the purification function in some of the purification passages 20 is hindered, or even when the time for replacing the purification filter medium 22 has come, it is only necessary to close one of the purification passages 20. The function can be secured by another system.

Further, since the purifying device 18 is of an open-to-atmosphere type with a structure in which the upper part is opened, the purifying resin 18 is replaced when the purifying resin as the purifying filter material is exchanged as in the case of the conventional closed type filter desalinator 7. By shutting down the system and opening and closing the lid, there is no need for a large-scale operation to release the seal.

Therefore, the container and the purifying device for the purifying filter medium 22
The makeup water tank 16, which is the outer peripheral container of 18, does not receive a large pressure other than the atmospheric pressure and the pool water 2 to be stored, and does not need to have a closed structure, so that the structure is simple and the production and maintenance are easy. Therefore, the amount of work involved in replacing the purification filter medium 22 is greatly reduced.

Further, it is easy to make each of the plurality of purifying filter media 22 into a shape and size that are easy to handle, and each filter media 22 is replaced. This eliminates the necessity of an operation such as backwashing as in the case of using a hollow fiber membrane type filter, so that equipment and control equipment necessary for the backwash operation are not required at all. As for the purifying resin contained in the mesh bag of the container in the purifying filter medium 22, when the purifying process reaches a predetermined amount, the purifying function is reduced by the trapped impurities, so that a new purifying resin is used as the used purifying resin. Need to be replaced.

This exchange operation is performed in units of the purification channel 20, and the exchange is performed on the purification filter medium 22 in a state where the purification resin is packed in a mesh bag which is a container. Therefore, it is basically a simple operation of putting the net bag in and out of the makeup water tank 16. That is, the arrangement of the purifying filter medium 22 with respect to each purifying flow path 20 is performed by putting a predetermined number of the purifying filter mediums 22 on the grid plate 21 of each purifying flow path 20, thereby forming the filtration layer 23. The arrangement work of the 22 does not require the use of complicated special equipment, and can be easily performed manually by a worker if a chain block, a hoist 27, or the like is used.

However, regarding the work of taking out from the purifying device 18 in the replenishing water tank 16, the used purifying resin contained in the purifying filter medium 22 has taken in the radioactive clad, which is the impurity, so Exposure prevention measures must be taken.

As shown in FIG. 3, a transparent shielding cover 30 in which a hanging rope 29 is previously attached to a hanging rope or the like in the vicinity of a chain block from which the purification filter medium 22 is taken out, and a hoist 27 such as a hoist 27 is provided. Is mounted so as to be slidable up and down, and when the purifying filter medium 22 is lifted by the suspending tool 28 via the hanging ring 26, the outer periphery of the purifying filter medium 22 is covered with the shielding cover 30.

As a result, the operator can directly clean the filter medium 22.
Because it will no longer be in contact with
Exposure of workers is prevented. In addition, the removed filter media
22 collects the net bag together with the net bag in a shielding container such as a drum, and separately treats it as solid waste.

The spent fuel pool 15 installed independently of the nuclear reactor allows the spent fuel taken out of the reactor to a certain extent in the fuel pool 1 as compared with the conventional fuel pool 1 that is close to the nuclear reactor. It is possible to transfer after cooling. Depending on such a fuel management operation, the cooling capacity of the heat exchanger 11, which is the cooling device, does not necessarily need to assume a heat value immediately after being taken out of the reactor.

Further, since the calorific value of the spent fuel pool 15 as a whole is small, even if the heat exchanger 11 temporarily stops functioning, the pool water temperature rises rapidly within a short time. Does not occur. For this reason, the pool water transfer pump 5 is provided with one system, and the pool water transfer pump 5 can repair the pool water temperature immediately by taking a corrective action in the event of a failure or the like, without always having a standby system. A significant rise can be prevented. This eliminates the need to install two pool water transfer pumps 5 in parallel.

When the spent fuel is once taken out to the fuel pool 1 and then transferred to the spent fuel pool 15 as described above, the radioactive fuel generated on the surface of the spent fuel in this process is used. Most of the cladding of the powder comes off. Conventionally, the pool water 2 is polluted by the clad, and therefore, in the spent fuel pool 15, the pool water 2 is extremely unlikely to be polluted.

Therefore, since the purification operation of the pool water 2 stored in the spent fuel pool 15 does not always need to be performed at all times, the quality of the pool water 2 of the spent fuel pool 15 is monitored online, When the water quality falls below the set value, the pool water transfer pump 5 is operated.

Further, by appropriately selecting and removing the dropping door 25 for each purification flow path 20 of the purification device 18, the operating rate of the purification filter medium 22 is increased, and the purification filter medium 22 in the stop purification flow path 20 is replaced. And the like can be performed at any time during the operation of the purification device 18, so that purification efficiency and maintainability are improved.

Since the second embodiment is a modification of the first embodiment according to claim 6, the operation and effect of the same structural parts as those of the first embodiment are the same. Therefore, the description will be omitted, and different portions will be described.

As shown in the perspective view of the purification filter in FIG. 4, in the purification device 18 built in the makeup water tank 16, a plurality of partition plates are provided.
The purifying filter medium 31 arranged in the purifying flow path 20 formed by being partitioned by 19 includes a container 32 containing a purifying resin therein,
Inside each of the purification channels 20, they are arranged on the grid plate 21 in the horizontal direction and the vertical direction, and are arranged to be close to each other.

Therefore, each of the containers 32 has at least two upper and lower surfaces, for example, a net-like shape which does not hinder the permeation of impurities, and has a rigid rectangular parallelepiped, in which a purifying resin is housed or a hollow fiber membrane is housed. The purification filter material 31 is constituted. Here, two of the purification filter media 31 are arranged in the horizontal direction and three are stacked in the vertical direction.
The gap between the adjacent purification filter media 31 and the wall of the makeup water tank 16, and further between the partition plate 19 and the lattice plate 21 is small, and the filtration layer 23 having a predetermined width and thickness is formed.

The operation of the above configuration is as follows.
Since the container 32 containing the filtering resin, which is 31, is arranged in an orderly combination in the horizontal direction and the vertical direction, between the purifying filter media 31 in the purifying flow path 20, and between the purifying filter material 31 and the partition plate 19 And the gap between the grid plate 21 and the like becomes smaller.

As a result, the pool water 2 flows through the gap formed around the purification filter 22 when a plurality of bag-containing purification resins are disposed as in the case of the purification filter 22 in the first embodiment. Since the short path is prevented when the purifying filter medium 31 is used, the occupation rate of the purifying filter medium is improved together with the purifying effect of the purifying device 18.

Further, unlike the purification resin packed in a bag, which is rich in flexibility, such as the purification filter medium 22 in the first embodiment, the container 32 of the purification filter medium 31 has a high mechanical strength, so that it has a small impact. For example, the purified resin can be prevented from flowing out into the pool water 2.

Further, as the purifying filter material 31, a hollow fiber membrane such as a hollow fiber membrane type filter can be accommodated in the container 32 instead of a disposable purifying resin. Also,
In this case, by providing a washing function, the container 32 can be easily applied to a reusable filter medium.

The third embodiment relates to a cooling device for pool water according to claim 11, and the operation and effects of the same structural parts as those of the first embodiment are the same. The description will be omitted, and different portions will be described. As shown in the system configuration diagram of FIG. 5, the pool water transfer pump 5 in the purification system of the spent fuel pool 15
And a small-capacity unit heat exchanger 34a-34n as a group of heat exchangers 33 for cooling the pool water 2 with the cooling water 12 between the spent fuel pool 15 and the pool water at the time. The number corresponding to the cooling processing amount of 2 is connected.

The spent fuel pool 15 has one purification system. For example, one unit heat exchanger 34a is initially connected. However, the capacity of the heat exchanger group 33 is limited to the total output of the future reactor. It is assumed that it corresponds to the cooling amount of the pool water 2 during operation. Further, the other plurality of unit heat exchangers 34b to 34n are sequentially connected in parallel so as to match the capacity in accordance with the predicted increase in the cooling processing amount, and are added to form the heat exchanger group 33. The cooling processing amount can be increased.

The operation of the above configuration is such that the spent fuel pool 15 installed independently of the reactor cools the taken-out spent fuel to a certain extent as compared with the conventional fuel pool 1 close to the reactor. It is possible to transfer afterwards. Therefore, depending on such fuel management operations,
Regarding the spent fuel pool 15 constructed in consideration of future demand, no spent fuel is taken out at the beginning of operation of the nuclear reactor after the establishment of the nuclear power plant.

For this reason, the cooling capacity in the spent fuel pool 15 is not necessarily set based on the amount of heat generated immediately after the spent fuel is taken out of the reactor core. If necessary, a single unit heat exchanger 34a having a small capacity can sufficiently be used.

That is, in the nuclear power plant, it is necessary to secure the installation locations of all the heat exchangers 34a to 34n which are the heat exchanger group 33 from the beginning of the establishment, but the heat exchangers in the spent fuel pool 15 are required. In the group 33, the amount of heat generated by the spent fuel is very small in the early stage of operation when the generation of the spent fuel is still small.

In such a case, the unit heat exchangers 34 a to 34 n in the heat exchanger group 33 are configured in a module with a cooling capacity, so that the amount of spent fuel stored in the spent fuel pool 15 increases. The unit heat exchangers 34a-
Operation is carried out so that 34n can be added sequentially.

Further, in the spent fuel pool 15, the spent fuel stored therein has a smaller calorific value as compared with the case of the conventional fuel pool 1. Even if some of the unit heat exchangers 34a to 34n temporarily stop functioning, the situation that the pool water temperature rises rapidly within a short time does not occur. Therefore, even if a spare system is not always prepared, at this time, by operating the other normal unit heat exchangers 34a to 34n, a remarkable rise in the pool water temperature can be prevented.

[0075]

As described above, according to the present invention, the construction and maintenance work of the pool water purification system and various devices are simplified by eliminating equipment such as a makeup water tank and a filtration desalter from a nuclear power plant. Can be. In addition, the labor and work time required for installing and operating various types of purification system equipment are reduced, and the reliability of operation and maintenance is improved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a spent fuel pool according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a main part of the spent fuel pool according to the first embodiment of the present invention.

FIG. 3 is a side view of the conveyance of the purification filter medium of the first embodiment according to the present invention.

FIG. 4 is a perspective view of a purification filter according to a second embodiment of the present invention.

FIG. 5 is a system configuration diagram of a spent fuel pool according to a third embodiment of the present invention.

FIG. 6 is a system configuration diagram of a conventional fuel pool and the like.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel pool, 1a ... Water surface of fuel pool, 2 ... Pool water, 3 ... Skimmer surge tank, 4 ... Pool water piping, 5 ...
Pool water transfer pump, 6 ... Overflow, 7 ... Filter desalination, 8 ... New resin supply tank, 9 ... Solid radioactive waste receiving tank, 10 ... Backwash water, 11 ... Heat exchanger, 12 ... Cooling water, 13
... make-up water tank, 14 ... make-up water transfer pump, 15 ... spent fuel pool, 15a ... water surface of spent fuel pool, 16 ... make-up water tank, 16a ... water surface of make-up water tank, 17a ... upper reservoir, 17b ...
Lower water storage unit, 18… Purification device, 19… Partition plate, 20… Purification channel, 21… Lattice plate, 22, 31… Purification filter medium, 23… Filtration layer, 24…
Weir, 25 ... Drop door, 26 ... Hanging ring, 27 ... Chain block,
Hoist, 28 ... hanging tool, 29 ... hanging string, 30 ... shielding cover,
32: container, 33: heat exchanger group, 34a to 34n: unit heat exchanger.

Claims (12)

[Claims] 1. A spent fuel pool for storing and cooling spent fuel taken out of a nuclear reactor, wherein the spent fuel pool communicates with the spent fuel pool to keep the pool water level constant and to have a replenishing device provided therein. Spent fuel pool with a water tank. 2. The spent fuel pool according to claim 1, wherein the makeup water tank is integrated near the spent fuel pool. 3. The spent fuel pool according to claim 1, wherein the purification device has a plurality of purification passages formed in parallel. 4. The spent fuel pool according to claim 3, wherein the plurality of purification passages in the purification device can be operated independently by opening and closing the respective purification passages. 5. The purifying apparatus according to claim 1, wherein at least one purifying filter medium containing purifying resin in a purifying flow path and containing a purifying resin in a flexible container having a mesh size through which impurities pass. Item 3. A spent fuel pool according to item 3. 6. The spent fuel pool according to claim 3, wherein said purifying device arranges containers of purifying filter media in a purifying flow path in a horizontal direction and a vertical direction. 7. The spent fuel pool according to claim 1, wherein the purification device maintains the pool water to be released to the atmosphere and purified at a hydrostatic pressure. 8. The spent fuel pool according to claim 7, wherein the purifying device has a structural part opened to the atmosphere as a place for carrying in and out the purifying filter medium. 9. The spent fuel pool according to claim 3, wherein the spent fuel pool is conveyed by covering a periphery of the purification filter medium with a shielding cover when replacing the purification filter medium. 10. The circulating system in which the spent fuel pool has a single circulation system in which pool water in the spent fuel pool returns to the spent fuel pool again via the purification device and the cooling device. Item 6. A spent fuel pool according to item 1. 11. The spent fuel pool, wherein a cooling device provided in a pool water circulation system is divided into a plurality of unit cooling devices in an efficient manner, and the unit cooling device of the unit cooling device responds to a rise in the temperature of the pool water. 2. The spent fuel pool according to claim 1, wherein the operating number is changed. 12. The spent fuel pool according to claim 1, wherein the spent fuel pool monitors the water quality of the pool water online and adjusts the operation of the purification function according to the degree of water quality deterioration. .