JP2001091692A - Chemical cleaning device for nuclear reactor structural component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chemical cleaning device for a nuclear reactor structural component allowing suppression of increase in pressure loss, reduction in a flow rate, or the like of an ion exchange resin tower, allowing reduction in a replacement frequency of an ion exchange resin to reduce an emission amount of waste, and allowing improvement of a radiation decontamination effect and simplification of facilities, or the like. SOLUTION: This chemical cleaning device for a nuclear reactor structural component decontaminates radioactive contamination of the structural component of a nuclear reactor by ion exchange action by use of a loop-like cleaning system circulating a chemical when the operation of the nuclear reactor stops. The cleaning system is provided with a backwash type filter device 5 capable of capturing suspension particles in a liquid flowing through the system and discharging the captured suspension particles by backwash.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical cleaning apparatus for a reactor structural part for chemically removing radioactive contamination of a structural part of a nuclear reactor, and more particularly to a method for removing suspended particles by using a backwash type filter device. The present invention relates to an apparatus for cleaning a structural component of a nuclear reactor, which is capable of cleaning while performing.

[0002]

2. Description of the Related Art Conventionally, as a chemical cleaning method for radioactive contamination of nuclear facilities, for example, metals and radioactive components in reactor water are dissolved by injecting chemicals, and ionized metals and radioactive components are ion-exchanged. Removal with resin has been performed. Some particles are insufficiently dissolved and are suspended in the liquid, but these particles are removed by deep-layer filtration using an ion exchange resin tower.

[0003] However, since such suspended particles are released relatively early in the washing process, the ion-exchange resin undergoes a resin tower before the ion-exchange resin breaks down ions due to ionized metal or radioactivity. Cause clogging,
Breakthrough from pressure or flow rate.

Therefore, conventionally, the ion-exchange resin must be discarded while leaving the effective ion-exchange capacity.
This is a factor that increases the amount of waste generated.

[0005]

In order to avoid the above-mentioned problems of the prior art, there has been known a method of installing a filter device upstream of an ion exchange resin tower as a pre-filter and combining the two. I have.

However, in the case of the pre-filter, if clogging occurs during cleaning, a process is delayed due to the replacement of the filter, and furthermore, since the filter captures a large amount of radioactivity, the exposure of the operator is prevented. A new problem arises which is an increasing factor.

[0007] In order to avoid this, equipment such as installing a shield against the increase in dose due to particle capture, such as providing an automatic exchanger or using a large-scale apparatus having a particle capture capacity until cleaning is completed, is used. It has to be enlarged.

If there is a risk that suspended particles may accumulate in the structural gaps of the delicate reactor structural parts to be cleaned during cleaning, flushing is performed so as not to impair the function and the suspended particles are removed. Additional work occurs.

Further, at the site where the medicine stagnates,
There are problems to be solved such as leaving a hot spot after cleaning and impairing the cleaning effect.

The present invention has been made in view of such circumstances, and can reduce an increase in pressure loss and a decrease in flow rate of an ion-exchange resin tower, reduce the frequency of ion-exchange resin exchange, and reduce the amount of waste generated. It is another object of the present invention to provide a chemical cleaning apparatus for structural components of a nuclear reactor, which can improve the effect of removing radioactive contamination and simplify the equipment.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, when the operation of a nuclear reactor is stopped, a loop-like cleaning system for circulating chemicals is used to perform ion exchange. In the chemical cleaning apparatus for nuclear reactor structural parts for radioactively removing the structural parts of the nuclear reactor, the cleaning system captures the suspended particles in the liquid flowing in the system and captures the suspended particles. A chemical cleaning device for a structural component of a nuclear reactor, comprising a backwash type filter device capable of discharging by backwashing.

According to a second aspect of the present invention, in the chemical cleaning apparatus for a nuclear reactor structural component according to the first aspect, in addition to the backwash type filter device, the diameter of the suspended particles that can be captured by the backwash type filter device is smaller. Provided is a chemical cleaning device for a structural component of a nuclear reactor, provided with a non-backwash type filter device capable of capturing suspended particles.

According to a third aspect of the present invention, in the chemical cleaning apparatus for a nuclear reactor structural component according to the first or second aspect, the cleaning system has an ion-exchange resin tower on the upstream side of the system and irradiates ultraviolet rays on the downstream side. A reactor structure comprising a backwash type filter device, or a backwash type filter device and a non-backwash type filter device, provided upstream of the ion exchange resin tower or the ultraviolet irradiation device. Provide a chemical cleaning device for parts.

According to a fourth aspect of the present invention, in the chemical cleaning apparatus for a reactor structural component according to any one of the first to third aspects, the reactor structural component to be cleaned has a complicated structure. Or, in the case of reactor structural parts having a structure in which suspended particles are easily deposited, a backwash type filter apparatus or a backwash type filter apparatus and a non-backwash type filter apparatus immediately before these reactor structural parts. Provided is a chemical cleaning apparatus for reactor structural parts, which is installed.

According to a fifth aspect of the present invention, in the chemical cleaning apparatus for a nuclear reactor structural component according to any one of the first to fourth aspects, the backwash type filter device includes the suspended particles discharged from the filter and the chemical cleaning. A backwash water receiving tank for receiving backwash water containing chemicals is provided, and the backwash water receiving tank is provided with a decomposing device for decomposing the chemical cleaning chemicals in the backwash water discharged from the filter into sludge. The present invention provides a chemical cleaning device for a reactor structural part, characterized by the following.

According to a sixth aspect of the present invention, in the chemical cleaning apparatus for a nuclear reactor structural component according to the fifth aspect, the decomposing apparatus is configured to inject a decomposing chemical for decomposing the chemical cleaning chemical by a chemical reaction, The present invention provides a chemical cleaning device for structural parts of a nuclear reactor, characterized in that the device is an ultraviolet irradiation device for decomposing the reactor, a cyclone separator decomposing by centrifugal force, or a combination thereof.

According to a seventh aspect of the present invention, in the chemical cleaning device for a nuclear reactor structural component according to the fifth or sixth aspect, a chemical cleaning chemical discharge line for discharging only the chemical cleaning chemical through a filter screen is provided in the backwash water receiving tank. Provided is a chemical cleaning apparatus for reactor structural parts, which is installed.

According to the invention of claim 8, in the chemical cleaning apparatus for structural parts of a nuclear reactor according to claim 5, the decomposition apparatus separates the suspended particles and the chemical cleaning chemical into the backwash water receiving tank by filtration. Provided is a chemical cleaning apparatus for a reactor structural component, characterized in that the apparatus has a drain plate.

According to a ninth aspect of the present invention, in the chemical cleaning apparatus for a reactor structural component according to the eighth aspect, the decomposing apparatus includes a sprinkler for washing the separated suspended particles on the drain plate. A chemical cleaning apparatus for structural parts of a nuclear reactor is provided.

In the present invention, the backwashing type filter device is used alone or in combination with the backwashing type filter device, for example, filters having different filter hole diameters are used in front and rear.

That is, in the present invention, particles are removed by providing a backwash type filter device in a washing system for circulating chemicals. The backwash type filter device has, for example, a plurality of filters, and can remove suspended particles without interrupting the washing operation by repeating backwashing sequentially for clogging. With such a backwash type filter device,
There is no need to replace the filter even if the filter is clogged.

Further, in the present invention, a non-backwashing filter device having a pore diameter smaller than the filter hole diameter of the backwashing filter device is installed downstream of the backwashing filter device, and the suspended liquid permeating the backwashing filter device is provided. Capture particles. That is, fine particles are removed after the roughing in the previous stage, and the fine particles are removed in the subsequent stage, rather than reducing the filter hole diameter of the upstream backwashing filter device. Thereby, efficiency can be improved.

In the present invention, the removal of suspended particles can be carried out during chemical cleaning. The removal of suspended particles is partially exfoliated in the circulation of water or hot water before the injection of the chemical, but is maximized after the injection of the chemical. Therefore, it is effective to capture particles during chemical cleaning.

In the present invention, the backwash type filter device, or the backwash type filter device and the non-backwash type filter device are installed in an effective place. Thereby, before the ion exchange resin breaks through the ions, it is possible to prevent water from being impeded due to clogging of the resin tower, and to maximize the ion exchange capacity. As a result, generation of secondary waste can be suppressed.

According to the present invention, a backwash type filter device, or a backwash type filter device and a non-backwash type filter device, are provided before a place where suspended particles intrude to maintain the soundness of the device. By installing the device, the soundness of the device can be ensured.

In a backwash type filter using system water as the backwash water, the chemical cleaning chemical itself becomes backwash water. Therefore, simultaneously discharged suspended particles may dissolve in the chemical cleaning chemicals while being held in the backwash water receiving tank. For this reason, when the capacity of the ion exchange resin is insufficient, the backwash water cannot be returned to the system, and the suspended particles must be held as sludge in the backwash water receiving tank.

On the other hand, in the present invention, the chemical cleaning chemical in the backwash water from the backwash type filter device is decomposed by injecting the decomposing chemical. That is, the ability of the chemical cleaning chemicals to dissolve suspended particles is lost by chemical decomposition of the chemical cleaning chemicals.

Further, in the present invention, means for decomposing the chemical cleaning chemicals by irradiation with hydrogen peroxide and ultraviolet rays is employed.

Further, in the present invention, the chemical cleaning chemicals are not decomposed, but the chemical cleaning chemicals and the suspended particles are separated, thereby preventing the dissolution of the suspended particles. That is, a filter screen is installed at the tip of the nozzle, and only a chemical cleaning chemical is discharged by a submersible pump.

Further, in the present invention, the suspended particles are accumulated on the draining plate by the solid-liquid separation of the suspended particles and the chemical cleaning agent, and the discharged chemical cleaning agent is discharged.

In order to enhance the effect of preventing the suspended particles from dissolving, water is sprayed on the suspended particles on the separated drain plate to wash the chemical cleaning chemicals with water.

In the present invention, the suspended particles separated and recovered are sent to the existing waste treatment facility together with the ion-exchange resin as waste sludge by means relating to the treatment of the suspended particles, whereby the batch treatment is carried out.

[0033]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment (FIGS. 1 to 3) FIG. 1 is a system diagram showing a first embodiment of the present invention.
And FIG. 3 are explanatory diagrams of the operation.

In this embodiment, a boiling water reactor (BWR)
When the operation is stopped, a large-scale chemical cleaning loop including the reactor pressure vessel 1, the recirculation system piping 2, and the pump 3 is configured.

The recirculation pipe 2 is connected in a closed loop by a temporary pipe 2a. In addition, another pipe 2b, 2
A chemical liquid circulation system is constituted by c and 2d. Piping 2
A chemical injection tank 11 is connected to d via a chemical injection pump 17, whereby a chemical liquid for chemical cleaning is supplied into the reactor pressure vessel 1.

The pipes 2b and 2c connect the bottom of the reactor pressure vessel 1 and the spray ring 18 in a closed loop, and have a split and integrated portion.

An ion exchange resin tower 4 is provided in the pipe 2c, and a backwash type filter device 5 is installed upstream of the ion exchange resin tower 4.

A backwash water receiving tank 21 is connected to the backwash type filter device 5 via a backwash water transfer line 25 having a backwash water discharge pump 15. The backwash water receiving tank 21 is connected to the upstream of the ion exchange resin tower 4 in the circulation pipe 2c via a pipe 16a having the decontamination liquid return pump 16. Thereby, after the suspended particles having a certain diameter or more are captured by the backwashing filter 5, the washing liquid is supplied to the ion exchange resin tower 4.

The cleaning liquid having undergone the ion exchange in the ion exchange resin tower 4 flows to the decontamination liquid return line 7 through the cooler 9 and the heater 10 by the decontamination agent circulation pump 8 of the pipe 2b. Then, it is returned to the spraying 18 in the furnace via the ultraviolet irradiation device 12 provided in this line. In addition, in the ultraviolet irradiation 12, the organic matter contained in the decontamination liquid is decomposed into carbon dioxide and water, whereby the liquid is circulated.

The exhaust from the reactor pressure vessel 1 is cooled by a vent cooler 13.

In such a configuration, a large number of filters are arranged in the backwashing filter device 5 so that they can be sequentially backwashed during the reactor water purification operation. Then, the backwash water generated thereby, for example, a portion of the supernatant liquid purified in the backwash water receiving tank 21 is supplied to the ion exchange resin tower 4. The pipes 2b and 2c are provided with a valve 2f so that the flow rate to each pipe can be adjusted.

FIG. 2 shows the operation of the purifying apparatus having the above configuration. Insoluble suspended particles released in the furnace and in the initial stage of the chemical cleaning from the recirculation system piping 2 purify the entire chemical cleaning loop. At this time, as shown in FIG.
Initially, the concentrations of metal and radioactive ions also increase, but the concentrations gradually decrease due to the flow of water through the ion exchange resin tower 4.

In FIG. 2, the vertical axis indicates the concentration in the cleaning solution, and the horizontal axis indicates the elapsed time. In the conventional example without the backwashing filter device 5, the reduction time of the suspended particle concentration A ₀ , the ion concentration B ₀ and the radioactivity concentration C ₀ takes much time. It is recognized that the concentration A ₁ , the ion concentration B ₁ and the radioactivity concentration C ₁ can be reduced in a shorter time than any of the conventional examples. That is, according to the present embodiment, it is understood that the radioactivity reduction effect can be improved as compared with the conventional example.

FIG. 3 shows the flow rate (vertical axis) of the ion-exchange resin tower 4 along with the time (horizontal axis).

The flow rate D ₁ of water flow according to the present embodiment is different from the flow rate D _{0 of the} conventional example, which is gradually reduced, because the clogging of suspended particles in the ion exchange resin tower 4 is largely suppressed. It can be seen that the radioactivity gradually decreases, and the radioactivity can be reduced by ion exchange. Therefore, according to the present embodiment, it is possible to avoid a decrease in the flow rate of water flowing through the resin tower due to the suspended particles due to the flow of water to the ion-exchange resin tower 4, thereby improving the performance.

Second Embodiment (FIGS. 4 to 6) FIG. 4 is a system diagram showing a second embodiment of the present invention. In this embodiment, in addition to the configuration of the first embodiment, a non-backwashing filter device 6 having a filter having a smaller filter hole diameter than the backwashing filter device 5 is provided downstream of the backwashing filter device 5.
Is installed. Other configurations are the same as those of the first embodiment, and therefore, the same reference numerals as in FIG. 1 are used in FIG. 4 to omit the description.

The operation of this embodiment will be described below.

The suspended particles released into the system during chemical cleaning have a particle size distribution as shown in FIG. 5, for example.
In the present embodiment, for example, the filter hole diameter of the backwash type filter device 5 is set to 20 μm. As a result, 20
The suspended particles of μm or less flow out of the backwash type filter device 5. In the present embodiment, the suspended particles that have flowed out can be captured by a non-backwash type filter device having a small filter pore size. Therefore, according to the present embodiment, the efficiency can be further improved by the two-stage filtration.

[0050] In the case where a smaller filter pore size of backwashing filter device 5, as shown by the curve F ₁ in FIG. 6, backwash frequency is increased. In this case, the processing time of the received backwash water may be insufficient, and the capacity of the backwash water receiving tank must be increased. On the other hand, the curve F
_As shown in ₂ , when the filter hole diameter is increased, the number of times of backwashing can be reduced.

Third Embodiment (FIG. 7) FIG. 7 is a system diagram showing a third embodiment of the present invention. In the present embodiment, the backwashing filter device is installed with emphasis on the soundness of the in-furnace equipment rather than the load of suspended particles on the ion exchange resin.

That is, in this embodiment, the backwashing filter device 5 is installed in the return line 7 to the reactor pressure vessel 1 in the chemical cleaning loop. This makes it possible to prevent suspended particles from entering the narrow part in the furnace and impairing the soundness of the equipment.

In FIG. 7, only the backwash type filter device 5 similar to that shown in FIG. 1 is installed, but the non-backwash type filter device 6 shown in FIG. 4 can also be provided.

Fourth Embodiment (FIG. 8) FIG. 8 is an enlarged view showing a fourth embodiment of the present invention.

In this embodiment, a decomposition chemical injection line 22 is provided in the backwash water receiving tank 21 of the backwash filter device 5. Note that a stirrer 26 is provided in the backwash water tank 21.

Under such a configuration, a decomposition chemical injection pump 23 is provided in the decomposition chemical injection line 22 so that the decomposition chemical can be injected from the decomposition chemical tank 24. Backwash water is supplied into the backwash water tank 21 from the filter backwash water transfer line 25, and the chemical cleaning chemicals in the backwash water are decomposed. For example, when the chemical cleaning chemical is oxalic acid, if a permanganate ion solution is used as a decomposition chemical, oxalic acid is decomposed into carbon dioxide and water by the following reaction, and manganese ions remain afterwards.

[0057]

Embedded image

Since the main components of the suspended particles are iron oxide, they will eventually dissolve in oxalic acid, but will not dissolve in an atmosphere such as the one on the right side of the above reaction formula. To settle.

The sludge 31 can be collected at any time or collectively.
Finally, the exhaust can be discharged by opening the valve 30. The decomposed oxalic acid becomes carbon dioxide and water. Carbon dioxide is exhausted from a vent pipe 27, and excess water is returned to the system by a supernatant water transfer pump 29 via a supernatant water transfer line. Thereby, purification in the system can be achieved.

Fifth Embodiment (FIG. 9) FIG. 9 is an enlarged view showing a fifth embodiment of the present invention.

As shown in FIG. 9, in this embodiment,
The hydrogen peroxide injection line 32 and the ultraviolet lamp 20 are immersed in the backwash water receiving tank 21 of the backwash type filter 5, so that the chemical cleaning chemicals in the backwash water to which the action of ultraviolet light is added are performed. ing. For example, if the chemical cleaning chemical is oxalic acid, supply of hydrogen peroxide and ultraviolet light
Decomposes into carbon dioxide and water as in the following reaction.

[0062]

Embedded image

In the fourth embodiment, as in the fourth embodiment, the oxalic acid is decomposed and the ability of dissolving the suspended particles in the backwash water is lost, so that the suspended particles remain as sludge. This operation is performed more efficiently.

Sixth Embodiment (FIG. 10) FIG. 10 is an enlarged view showing a sixth embodiment of the present invention.

As shown in FIG. 10, in this embodiment, the suspended particles are mechanically prevented from dissolving in the chemical washing chemical in the backwash water receiving tank 21. That is, the suspended particles and the chemical cleaning chemicals are mechanically separated.

In FIG. 10, the backwash water from the backwash filter device is supplied to a cyclone separator 47 via a backwash water transfer line 25, where it is separated into suspended particles 36 and a chemical cleaning agent 37. You. The chemical cleaning chemicals exit from the top of the cyclone separator tower 47 and are returned to the piping loop. On the other hand, the suspended particles are discharged from the bottom of the cyclone separator 47 to the backwash water receiving tank 21 and accumulated.
Since the suspended particles contain radioactivity, the periphery of the backwash water receiving tank 21 is covered with a shield 46 so as to cope with an increase in radiation dose due to accumulation.

Seventh Embodiment (FIG. 11) FIG. 11 is an enlarged view showing a seventh embodiment of the present invention.

In this embodiment, as shown in FIG. 11, a water level meter 43 is provided in the backwash water receiving tank 21 of the backwash filter.
And a discharge nozzle 45 having a screen 44.

Then, backwash water, that is, chemical cleaning chemical 3
When 7 reaches a certain level, the pump discharges the liquid from the nozzle. The suspended particles 36 are blocked by the screen 44 and remain in the tank, and only the chemical cleaning agent 37 is discharged.

While the amount of the suspended particles 36 is increased, the amount of the chemical cleaning agent 37 is not more than a predetermined amount. Therefore, no metal salt having a saturation solubility or higher exists in the discharged chemical cleaning solution.

Since the suspended particles contain radioactivity, also in the present embodiment, the surroundings 12 of the backwash water receiving tank 21 are shielded so as to cope with an increase in radiation dose due to accumulation.
Covered with.

According to the present embodiment, the configuration can be simplified.

Eighth Embodiment (FIG. 12) This embodiment also has a structure in which suspended particles are mechanically prevented from being dissolved in a chemical cleaning chemical in the backwash water receiving tank, that is, the suspended particles and the chemical cleaning chemical are used. Are mechanically separated from each other.

FIG. 12 is an enlarged view showing the seventh embodiment of the present invention. As shown in FIG. 12, a funnel-shaped draining plate 35 is provided in the backwash water receiving tank 21 of the backwash filter device 5. A large number of small holes are formed in the draining plate 35. Backwashing water is supplied from the backwashing water transfer line 25 to the draining plate 35, and suspended particles 36 in the backwashing water and chemical cleaning chemicals are supplied. 37 are separated from each other. The hole diameter of the draining plate 35 is equal to or slightly smaller than the hole diameter of the backwash type filter. Further, in order to shorten the time required for separation, suction is performed by the pump 39 of the chemical cleaning chemical transfer line 38. The separated chemical cleaning chemicals are returned to the chemical cleaning system.

According to the present embodiment, the structure can be simplified.

Ninth Embodiment (FIG. 13) This embodiment also mechanically prevents suspended particles from dissolving in chemical cleaning chemicals in the backwash water receiving tank.

FIG. 13 is an enlarged view showing an eighth embodiment of the present invention.

This embodiment is similar to the one shown in FIG.
A draining plate 35 is provided in the backwashing water receiving tank 21 of the backwashing filter device 5 so that suspended particles 36 in the backwashing water and the chemical cleaning agent 37 are separated.

In this embodiment, a water washing device 40 is provided above the draining plate 35 for spraying the separated suspended particles to wash the chemical cleaning chemicals attached to the particles. The cleaning water is discharged in the same manner as the chemical cleaning chemicals.

[0080]

As described in detail above, according to the present invention, clogging of the ion exchange resin tower by suspended particles in the liquid in the chemical cleaning step is prevented, and the pressure loss of the ion exchange resin tower is increased. Thus, the flow rate is reduced. Therefore,
The exchange frequency of the ion exchange resin can be reduced, and the amount of waste can be reduced.

Further, according to the present invention, since the suspended particles are removed before they are dissolved, the ion load on the ion exchange resin is reduced. Therefore, the amount of ion exchange resin used is reduced, and waste can be reduced. In addition, the reduced amount of suspended particles deposited on the structural components of the reactor during the chemical cleaning operation can achieve a much better radiation decontamination effect than conventional devices. Further, effects such as the flushing step after chemical cleaning can be eliminated or simplified.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of a chemical cleaning apparatus for a reactor structural component according to the present invention.

FIG. 2 is an operation explanatory view of the first embodiment.

FIG. 3 is a diagram illustrating the operation of the first embodiment.

FIG. 4 is a system diagram showing a second embodiment of the chemical cleaning apparatus for reactor structural parts according to the present invention.

FIG. 5 is an operation explanatory view of the second embodiment.

FIG. 6 is an operation explanatory view of the second embodiment.

FIG. 7 is a system diagram showing a third embodiment of the chemical cleaning apparatus for a reactor structural component according to the present invention.

FIG. 8 is an enlarged view showing a fourth embodiment of the chemical cleaning apparatus for a reactor structural component according to the present invention.

FIG. 9 is an enlarged view showing a fifth embodiment of the chemical cleaning apparatus for reactor structural parts according to the present invention.

FIG. 10 is an enlarged view showing a sixth embodiment of the chemical cleaning apparatus for a reactor structural component according to the present invention.

FIG. 11 is an enlarged view showing a seventh embodiment of the chemical cleaning apparatus for a reactor structural part according to the present invention.

FIG. 12 is an enlarged view showing an eighth embodiment of the chemical cleaning apparatus for a reactor structural part according to the present invention.

FIG. 13 is an enlarged view showing a ninth embodiment of the chemical cleaning apparatus for a reactor structural component according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor pressure vessel 2 Recirculation system piping 3 Reactor recirculation pump 4 Ion exchange resin tower 5 Backwashing filter 6 Non-backwashing filter 7 Return line in decontamination liquid furnace 8 Decontamination agent circulation pump 9 Cooler 10 Heater DESCRIPTION OF SYMBOLS 11 Chemical injection tank 12 Ultraviolet irradiation device 13 Vent cooler 14 Purification pump 15 Reverse diving discharge pump 16 Decontamination liquid return pump 17 Chemical injection pump 18 Spraying 19 Filtration pump 20 Ultraviolet lamp 21 Backwash water receiving tank 22 Decomposition chemical injection line 23 Disassembly Chemical injection pump 24 Decomposed chemical tank 25 Backwash water transfer line 26 Stirrer 27 Vent 28 Supernatant water transfer line 29 Supernatant water transfer pump 30 Sludge discharge valve 31 Sludge 32 Hydrogen peroxide injection line 33 Hydrogen peroxide injection pump 34 Hydrogen peroxide tank 35 Drainer board 36 Suspended particles 37 Chemical cleaning chemicals 38 Chemical cleaning chemicals transfer line 39 Chemical cleaning chemicals transfer pump 40 Washing device 41 Water tank 42 Sprinkling pump 43 Water level gauge 44 Screen 45 Discharge nozzle 46 Shield 47 Cyclone separator

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[Procedure amendment]

[Submission Date] June 19, 2000 (2006.1.
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, in the chemical cleaning apparatus for a nuclear reactor structural component according to the first aspect, in addition to the backwash type filter device, the diameter of the suspended particles that can be captured by the backwash type filter device is smaller. A chemical cleaning device for a structural component of a nuclear reactor, wherein a non-backwash type filter device capable of capturing suspended particles is provided downstream of the backwash type filter device.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

Claims (9)

[Claims] 1. Chemical cleaning of a reactor structural component for removing radioactive contamination of a structural component of the reactor by ion exchange using a loop cleaning system for circulating chemicals when the reactor is shut down. In the apparatus, the washing system includes:
A chemical cleaning device for a nuclear reactor structural component, comprising: a backwash type filter device capable of capturing suspended particles in a liquid flowing in the system and discharging the captured suspended particles by backwashing. 2. The chemical cleaning apparatus for a reactor structural component according to claim 1, wherein, in addition to the backwash type filter device, trapped suspended particles smaller in diameter than the suspended particles that can be captured by the backwash type filter device. A chemical cleaning apparatus for a reactor structural part, comprising a non-backwash type filter device capable of being provided. 3. The chemical cleaning apparatus for reactor structural parts according to claim 1, wherein the cleaning system has an ion exchange resin tower upstream of the system and an ultraviolet irradiation device downstream. Backwash type filter device, or a backwash type filter device and a non-backwash type filter device, provided upstream of the ion-exchange resin tower or the ultraviolet irradiation device, chemical cleaning device for nuclear reactor structural parts . 4. The reactor structural component chemical cleaning apparatus according to claim 1, wherein the reactor structural component to be cleaned has a complicated structure or suspended particles. Is a reactor structural component having a structure that is easily sedimented, characterized in that a backwash type filter device or a backwash type filter device and a non-backwash type filter device are installed immediately before these reactor structural components. Cleaning equipment for reactor structural parts. 5. The chemical cleaning apparatus for a reactor structural component according to claim 1, wherein the backwash type filter apparatus includes a backwash containing suspended particles discharged from the filter and a chemical cleaning chemical. A backwash water receiving tank for receiving water, wherein the backwash water receiving tank is provided with a decomposition device for decomposing chemical cleaning chemicals in the backwash water discharged from the filter into sludge. Chemical cleaning equipment for furnace structural parts. 6. The chemical cleaning apparatus for a nuclear reactor structural component according to claim 5, wherein the decomposition apparatus injects a decomposition chemical for decomposing the chemical cleaning chemical by a chemical reaction, and optically performs decomposition. A chemical cleaning device for structural parts of a nuclear reactor, comprising an ultraviolet irradiation device, a cyclone separator decomposed by centrifugal force, or a combination thereof. 7. The chemical cleaning apparatus for a reactor structural part according to claim 5, wherein a chemical cleaning chemical discharge line for discharging only the chemical cleaning chemical through a filter screen is installed in the backwash water receiving tank. Cleaning equipment for reactor structural parts. 8. The chemical cleaning device for a nuclear reactor structural component according to claim 5, wherein the decomposing device includes: a backwash water receiving tank;
A chemical cleaning apparatus for reactor structural parts, comprising a drainer for separating suspended particles and a chemical cleaning chemical by a filtering action. 9. The chemical cleaning device for a nuclear reactor structural component according to claim 8, wherein the disassembling device includes a sprinkler for washing the separated suspended particles on the drain plate. Chemical cleaning equipment for reactor structural parts.