JP2002148389A - Method and apparatus for solidifying radioactive waste solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To complete volume reduction through a simple working process and in a short time and to detect the correct timing of dispensing. SOLUTION: A radioactive waste solution containing a salt for taking in crystal water of boric acid or a borate or the like is contained in an evaporator 2 and agitated and heated to draw a gas out of the evaporator 2 so as to enrich the waste solution. A determination is made as to whether or not the waste solution has been enriched to a predetermined concentration, based on the agitation load, the weight of the waste solution in the evaporator 2, and the amount of an enriched solution produced from the gas. When the predetermined concentration is reached, the waste solution is transferred from the evaporator 2 to a solidifying container 23 and solidified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for solidifying a radioactive liquid waste by discharging the liquid from an evaporator to a solidification container.

[0002]

2. Description of the Related Art It is necessary to reduce the volume of radioactive waste liquid discharged from a nuclear power plant or the like by removing water from the waste liquid in order to effectively use a storage place. Accordingly, various methods for reducing the volume of radioactive waste liquid have been proposed and implemented. For example, Japanese Patent Publication No. 63-67878 discloses a method that focuses on the relationship between boric acid in waste liquid and the PH value. A method for greatly reducing the volume of radioactive liquid waste has been proposed.

[0003] That is, the PH value of the waste liquid is set to a neutral state by charging the radioactive waste liquid and the sodium hydroxide solution into the evaporator. Then, while maintaining the neutral state, the waste liquid is heated to evaporate the water, thereby concentrating the waste liquid to sufficiently reduce the volume. When the radioactive waste liquid becomes a waste liquid concentrate containing high concentration of boric acid, the waste liquid concentrate is transferred from the evaporator to a storage container, and oxalic acid or the like is added to the waste liquid concentrate in the storage container to shift the PH value to the acidic side. Change and cool. Then, the waste liquid concentrate is separated into a sediment composed of borate and the like and a liquid, and the liquid is returned to the above-mentioned evaporator and re-concentrated, while the sediment is transferred to a vacuum evaporator, and the vacuum evaporator is removed. Dry the sediment to a slightly moist powder in. Thereby, according to the conventional method, by sequentially reducing the volume of radioactive waste liquid in the evaporator, the storage container, and the vacuum evaporator, it is possible to finally reduce the volume to a powdery body. Has become.

[0004]

However, in the above-mentioned conventional method, it is necessary to transfer to a evaporator, a storage vessel and a vacuum evaporator in the process of reducing the volume of radioactive waste liquid, which complicates the operation process. In addition, there is a problem that it takes a long time to reduce the volume to a powdery body due to the time required for transfer.

In order to eliminate the need for such transfer to each device, the concentration of the radioactive waste liquid by evaporation in the evaporator is continued until the dissolved boric acid precipitates as borate. A method has been considered in which the borate is solidified by withdrawing it from the evaporator into a solidification container at a stretch. However, in the case of this method, the method of detecting the state immediately before precipitation as a borate was unknown, so that the timing of dispensing could not be accurately grasped. There is a problem that the borate cannot be solidified in the evaporator, or the borate can be solidified in the evaporator due to excessive concentration.

Accordingly, the present invention provides a method and an apparatus for solidifying a radioactive liquid waste, in which the volume reduction can be completed in a short time with a simple operation process and the timing of dispensing can be accurately known. Things.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a radioactive waste liquid containing a salt for taking in water of crystallization such as boric acid or borate is charged into an evaporator, and This is a method for solidifying a radioactive waste liquid by stirring and heating the radioactive waste liquid, extracting gas from the evaporator, concentrating the radioactive waste liquid, and transferring the radioactive waste liquid from the evaporator to a solidification container when the concentration reaches a predetermined concentration. And determining whether or not the radioactive waste liquid has been concentrated to a predetermined concentration based on the load at the time of stirring, the weight of the radioactive waste liquid in the evaporator, and the amount of condensate generated from the gas. It is characterized by:

[0008] According to the above configuration, the radioactive waste liquid is sufficiently concentrated in the evaporator to reduce the volume, and then discharged from the evaporator to the solidification container, whereby the radioactive waste liquid is converted into borate or the like in the solidification container. Can be solidified. This eliminates the need to transfer the radioactive waste liquid to each device when reducing the volume of the radioactive waste liquid, so that a large volume reduction can be realized in a short time in a simple operation process.

Further, the enrichment immediately before precipitation as borate or the like is detected on the basis of easily detectable parameters such as the load at the time of stirring, the weight of the radioactive waste liquid and the amount of the condensate, and the radioactive waste liquid is removed from the evaporator. You can know exactly when to pay out. As a result, it is possible to reliably prevent the radioactive waste liquid from solidifying in the evaporator due to excessive concentration, or to prevent solidification in the solidification container due to insufficient concentration.

A second aspect of the present invention is an apparatus for solidifying a radioactive waste liquid, wherein the radioactive waste liquid containing boric acid is concentrated while maintaining a neutral state, and is transferred to a solidification container and solidified when a predetermined concentration is reached. An evaporator containing the radioactive waste liquid and having an outlet formed at the bottom, a discharge device provided with the outlet of the evaporator openable and connectable to the solidification container, A heating device capable of heating the radioactive waste liquid to an arbitrary evaporation rate, a stirring device for stirring the radioactive waste liquid contained in the evaporator, a vacuum exhaust device for extracting gas from the evaporator, and cooling the gas. A condenser that generates a condensate, a condensate tank that stores the condensate,
A load detector for detecting the load of the stirring device, a weight detector for detecting the weight of the radioactive waste liquid contained in the evaporator, and a storage amount detector for detecting the storage amount of the condensate in the condensate tank. A determination device for determining whether or not the radioactive waste liquid has been concentrated to a predetermined concentration based on the load of the stirring device, the weight of the radioactive waste liquid, and the storage amount of the condensate.

According to the above configuration, the solidification method according to the first aspect can be realized with a simple device configuration. Then, the volume reduction can be completed in a short time with a simple work process, and the timing of payout can be accurately known.

According to a third aspect of the present invention, there is provided the apparatus for solidifying radioactive waste liquid according to the second aspect, wherein a storage speed detector for detecting a storage speed of the condensate in the condensate tank, and wherein the storage speed is a predetermined value. And a first heating control device for controlling the heating of the radioactive waste liquid by the heating device. According to the above configuration, it is possible to reliably prevent a decrease in the decontamination efficiency due to the heating device wrongly heating the radioactive waste liquid (evaporation rate).

According to a fourth aspect of the present invention, there is provided an apparatus for solidifying a radioactive liquid waste according to the second aspect, wherein a heat consumption detector for detecting a heat consumption of a cooling medium used for cooling gas in the condenser; A second heating control device for controlling the heating of the radioactive waste liquid by the heating device so that the heat consumption becomes a predetermined value. According to the above configuration, it is possible to reliably prevent a decrease in the decontamination efficiency due to the heating device wrongly heating the radioactive waste liquid (evaporation rate).

According to a fifth aspect of the present invention, there is provided the apparatus for solidifying a radioactive liquid waste according to the second aspect, wherein an inner space of the evaporator from which gas is extracted by the vacuum exhaust device, Is characterized by having a communication mechanism capable of communicating with According to the above configuration, since the pressure of the solidification container and the evaporator can be set to approximately the same pressure, the discharge of the radioactive waste liquid from the evaporator to the solidification container can be surely instantaneously performed.

According to a sixth aspect of the present invention, there is provided the apparatus for solidifying radioactive waste liquid according to the second aspect, wherein the diluent is connected to the evaporator and can be charged with a diluent for diluting the radioactive waste liquid in the evaporator. It is characterized by having an injection line. According to the above configuration, when an abnormality occurs in the concentration state of the radioactive waste liquid in the evaporator, solidification of the radioactive waste liquid in the evaporator can be prevented by introducing the diluent. As a result, it is possible to avoid a difficult recovery operation of removing the solidified material from the evaporator or dissolving the solidified material.

According to a seventh aspect of the present invention, there is provided the apparatus for solidifying radioactive waste liquid according to the second aspect, further comprising an electric conductivity detector for detecting the electric conductivity of the condensate generated in the condenser. Features. According to the above configuration, since the foaming state of the radioactive waste liquid in the evaporator can be grasped through the electric conductivity, the concentrate of the radioactive waste liquid is exhausted together with the gas due to the growth of bubbles to contaminate the condensate. It is possible to prevent such a problem.

The invention according to claim 8 is an apparatus for solidifying a radioactive liquid waste according to any one of claims 2 to 7, wherein the solidification container has a primary lid connectable to the dispensing device. , And a secondary lid that covers the primary lid in a sealed state. According to the above configuration, even when radioactive waste liquid adheres to the primary lid when dispensing from the dispensing device to the solidification container, the primary lid is covered with the secondary lid in a sealed state, so that the solidification is performed. When storing the container, the radioactive waste liquid on the primary lid does not leak to the outside.

According to a ninth aspect of the present invention, there is provided the radioactive waste liquid solidifying apparatus according to the eighth aspect, wherein the volume of the solidification container can accommodate the entire amount of the radioactive waste liquid concentrated to a predetermined concentration in the evaporator. It is characterized by being set to the degree.
According to the above configuration, since all the radioactive waste liquid in the evaporator can be discharged to the solidification container at a burst with a large outflow amount, the radioactive waste liquid is discharged in a small amount as in the case of dispensing a plurality of times. As a result, it does not remain as a solid in the evaporator or in the dispensing device.

According to a tenth aspect of the present invention, there is provided an apparatus for solidifying a radioactive liquid waste according to any one of the second to seventh aspects,
The solidification container includes a cylindrical body, a lid that covers an upper inside of the body, and a hook that extends in an inner circumferential direction from an upper edge of the body. According to the above configuration, the attachment / detachment and handling of the solidification container can be performed by the inner gripping of the hook portion. as a result,
Since the container hanging tool does not protrude other than the outer diameter of the solidified container, the container can be handled even on a transport route with limited space. Further, interference with an adjacent solidification container at the time of attaching / detaching the hanging tool can be avoided.

An eleventh aspect of the present invention is the radioactive liquid waste solidifying apparatus according to the tenth aspect, wherein the hook portion is provided on the entire inner periphery of the upper edge. According to the above configuration, the solidified container can be gripped by the inner grip with respect to the hook portion from any direction, regardless of the direction in which the hanging tool is gripped. as a result,
In particular, effective operation can be performed in a situation where operability such as remote operation is limited.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the method for solidifying radioactive waste liquid according to the present embodiment is performed in a solidification treatment facility for radioactive waste liquid discharged from a nuclear power plant, a reprocessing plant, a research and experiment facility, or the like. This solidification treatment facility includes an evaporator 1 for evaporating radioactive waste liquid. The evaporator 1 has an evaporator 2 that stores a radioactive waste liquid containing sodium nitrate and additives in an airtight state.
Note that the additive is for discharging the concentrate to a solidification container and then taking in the free water in the concentrate as crystallization water to solidify. This is for neutralizing the radioactive waste liquid and maintaining it in a neutral state so that boric acid does not precipitate as borate even when the concentration of boric acid becomes high. For example, Na2B4O7 with 10 crystallization waters or 12 There is Na2SO4 with water of crystallization.

The evaporator 2 has a cylindrical side wall 2a, an upper wall 2b provided to cover the upper end surface of the side wall 2a, and an inverted conical shape from the lower edge of the side wall 2a. And a lower surface wall 2c having a lower end opened. A heating device 20 is provided around the side wall 2 a and the lower surface wall 2 c in the evaporator 2.
Heats and maintains the radioactive waste liquid and the like contained in the evaporator 2 at a predetermined evaporation rate. Further, the evaporator 2 is supported via a load cell 21. The load cell 21
The total weight of the evaporator 2 containing the radioactive waste liquid or the like is detected, and the detected value is output as a weight signal to a determination device 19 described later.

A stirring device 7 for stirring the radioactive waste liquid in the evaporator 2 is provided at the center of the upper wall 2b of the evaporator 2.
Is provided. The stirring device 7 is provided at a lower end portion of the rotating shaft 7a and rotatably provided in a central portion of the upper surface wall 2b so as to be rotatable in a vertical direction, and a stirring device (not shown) for stirring the radioactive waste liquid in the evaporator 2. It has a blade and a drive motor 7b that is connected to the upper end of the rotating shaft 7a and that drives the rotating shaft 7a to rotate. The stirrer 7 is provided with a load detector 8, which detects the load (power consumption) of the drive motor 7b based on the drive current and the drive voltage, and uses the detected value as a load signal. Output to the determination device 19 described later.

Further, on the upper wall 2b of the evaporator 2, a waste liquid pipe 4 for allowing a radioactive waste liquid to which an additive is added in advance to flow into the evaporator 2 and a diluent such as water or steam to flow into the evaporator 2 The pipe 42 for the diluent to be discharged is connected to the pipe 6 for the exhaust, which allows the gas such as air or steam to flow out of the evaporator 2.
A condenser 9 is connected to the exhaust pipe 6. The condenser 9 has a body 9a through which gas flows, and a cooling water passage 9b wound around the body 9a.
A condensed liquid is generated by cooling the gas flowing through a. An exhaust pipe 10a for discharging gas is connected to an upper surface, and a drain pipe 10b for discharging dropped condensate is connected to a lower surface of the rear part of the body 9a.

The above-described exhaust pipe 10a is connected to the vacuum exhaust device 1
1 connected. The evacuation device 11 includes a fan 12
And a vacuum chamber 13. Fan 12
Is connected to the above-mentioned exhaust pipe 10a via a vacuum tank 13, and sucks gas from the condenser 9 and discharges it to an off-gas system. The condensate tank 15 has a drain pipe 10 for the condenser 9.
b is connected. Then, the condensed liquid tank 15 stores the condensed liquid from the condenser 9 and discharges the condensed liquid to the condensed liquid storage tank when the solidification processing for one batch in the evaporator 2 is completed. Further, a liquid level gauge 17 is provided in the condensed liquid tank 15, and the liquid level gauge 17 detects the height position of the liquid level of the condensed liquid,
This detection value is output to the determination device 19 and the heating control device 43 as a liquid level signal.

The heating control device 43 obtains the rate of rise of the condensed liquid level in the condensed liquid tank 15 based on the liquid level signal, and sets the heating apparatus 20 so that the rising rate becomes a predetermined value.
The amount of heating steam supplied from is controlled. On the other hand, the judging device 19 takes in the liquid level signal from the liquid level gauge 17, the weight signal from the load cell 21, and the load signal from the load detector 8, and based on these signals, the internal The concentration state of the radioactive waste liquid is obtained, and when the concentration state becomes a predetermined concentration state, the opening information is notified to the operator. That is, the determination device 19 includes a first comparison unit that compares the weight indicated by the weight signal with the first comparison value, a second comparison unit that compares the load value indicated by the load signal with the second comparison value, A third comparison unit that compares the liquid level indicated by the signal with a third comparison value;
Receiving comparison signals from the first to third comparison units,
The comparison signal of the first comparison unit indicates a weight less than the first comparison value;
When the comparison signal of the second comparison unit indicates a load value equal to or greater than the second comparison value and the comparison signal of the third determination unit indicates a liquid level higher than the third comparison value, the opening timing of the dispensing device 22 is opened. And an informing unit that informs the operator of the opening timing by sound or light.

The dispensing device 22, which is notified of the opening timing by the above-mentioned judging device 19, is provided on the lower surface wall 2c of the evaporator 2.
At the lower end. The dispensing device 22 has a valve unit that can open and close the opening of the evaporator 2 and a connection unit that can be connected to the solidification container 23 in a sealed state. Further, one end of the communication pipe 40 is connected to the dispensing device 22. The other end of the communication pipe 40 is connected to the upper internal space of the evaporator 2, and the flow path can be opened and closed by a valve 41. The communication pipe 40 and the valve 41 constitute a communication mechanism for communicating the internal space of the evaporator 2 and the internal space of the solidification container 23 with the dispensing device 22. The pressure is reduced.

The above solidification container 23 is shown in FIG.
As shown in (b), it has a volume that can accommodate the entire amount of radioactive waste liquid at the time of dispensing, and is provided at a predetermined distance from the cylindrical body 24 and the lower end surface of the body 24. It is formed in the shape of a drum having a bottom part 25. A primary cover 2 for closing the upper surface of the body 24 is provided on the upper part of the body 24.
6 is provided at a predetermined distance from the upper end surface. 1
The next lid 26 is provided on an annular first annular plate 26a having an outer peripheral end joined to the inner wall surface of the body portion 24 and an inner peripheral end of the first annular plate 26a, and a discharge port 26c is formed at the center. A second annular plate 26b, a plurality of screwing portions 26d protruding from the lower surface of the second annular plate 26b, and a convex portion fitted to the payout opening 26c. And a bolt member 26 for fastening the sealing plate 26e and the second annular plate 26b by screwing into the screwing portion 26d.
f, and a handle 2 formed at the center of the upper surface of the sealing plate 26e.
6 g. First annular plate 26a and second annular plate 2
6b may be a structure integrally manufactured.

The upper edge of the body 24 is provided with the hook 2
4a is formed by bending the entire circumference in the inner circumferential direction, and a ring member 27 is provided on the outer circumferential surface. 3 (a) and 3 (b), a secondary lid 28 for preventing the radioactive waste liquid attached to the primary lid 26 from leaking to the outside at the upper edge thereof. It can be installed. The secondary lid 28 can be attached by remote control as needed. The secondary lid 28 includes a flat plate portion 28a formed so as to cover the entire upper surface of the body portion 24, a curved portion 28b curved downward from the outer peripheral end of the flat plate portion 28a,
A packing 29 attached to the lower surface of the curved portion 28b and capable of closely contacting with the hook portion 24a and the ring member 27 of the body portion 24, and equidistantly on the lower surface outer peripheral side of the flat plate portion 28a so as to contact the primary lid 26. And a support portion 28c provided by the above.

The secondary lid 28 can be attached to the body 24 by a regular band 30 or a stacking band 31. As shown in FIGS. 4 and 5, the service band 30 has a band member 35 having a U-shaped cross section with an annular end cut off, and a flat plate member 36 joined to an upper portion of the band member 35. ing. The plate members 36 are arranged at equal intervals at a plurality of positions of the band member 35 so as to come into contact with the plate portion 28a of the secondary lid 28 when the band member 35 is attached. Further, the fastening member 32 is provided at the separated one end of the regular band member 30. Fastening member 3
2 is a band member 3 as shown in FIGS.
5, and then hang down to insert a through hole 3 in the lower end.
2b has an insertion member 32a formed therein. The insertion members 32 a are provided at respective ends of the band member 35. And these insertion members 32a, 32
In the regular band 30 provided with a, the bolt member 33 is inserted through one of the insertion holes 32b, and is screwed into the other insertion member 32a. Making it possible.

As shown in FIGS. 7 and 8, the stacking band 31 has a guide fitting 37 in addition to the configuration of the above-mentioned ordinary band 30. The guide fitting 37 is formed in a shape that is joined to the upper surface of the band member 35 and then rises while being inclined in the outer peripheral direction of the band member 35. The guide fittings 37 are arranged at a plurality of locations of the band member 35. When the solidification containers 23 shown in FIG.
The central axes of the two are matched.

Another preferred embodiment of the solidification container 123 will be described with reference to FIGS. On the upper edge of the body portion 124, a ring member 127 is formed by being bent in the outer peripheral direction, and a hook portion 124a is provided by fixing an angle to the entire length of the inner peripheral surface. The outer peripheral end of the primary lid 126 is joined to the inner wall surface of the body portion 124, and has an annular plate 126a having a payout port 126c formed in the center, and a sealing plate 126e for sealing the payout port 126c. 1
As shown in FIGS. 9 and 10, the next lid 126 has a length and a diameter on the inner peripheral portion of the annular plate 126a in order to position the solidification container 123 by closing the solidification container 123 with the sealing plate 126e by remote control. Two different types of large and small guide pins 139 are provided. The annular plate 126a is provided with six guide holes 143, and a screwing portion 141 is protruded from the lower surface of the corresponding position. The screw portion 141 is provided with a screw hole 141a. The guide hole 143 has a larger diameter than the screw hole 141a.

The sealing member 126e is provided with the bolt member 1
A screw hole 141a through which the hole 40 is inserted is provided. This bolt member has a bolt head 140 that projects in a substantially conical shape.
a, an intermediate shaft portion 140b, and a screw portion 140c. When the bolt member 140 is screwed into the screw hole 141a and the screw portion 140c passes through the screw hole 141a, the shaft portion 1
40b penetrates freely, the head 140a and the screw 140c
With this, it is prevented from falling out of the screw hole 141a. The bolt member 140 freely penetrates the guide hole 143 of the annular plate 126a, reaches the screw portion 141, and is screwed and fixed to the screw hole 141a. Further, two types of large and small positioning holes 142 for penetrating the guide pins 139 are provided at positions corresponding to the guide pins 139 in the sealing plate 126e.

In the above configuration, a method of solidifying the radioactive waste liquid through the operation of the solidification treatment facility will be described.

First, as shown in FIG. 1, a predetermined amount of radioactive waste liquid to which an additive has been added is introduced into the evaporator 2 via a waste liquid pipe 4. Thereafter, the weight of the evaporator 2 containing the radioactive waste liquid and the additive is detected by the load cell 21 at regular intervals, and is output to the determination device 19 as a weight signal.

Next, the radioactive waste liquid in the evaporator 2 is heated to a predetermined temperature by the heating device 20 while being stirred by the stirring device 7. Then, the load (power consumption) of the drive motor 7b of the stirring device 7 is detected by the load detector 8, and is output to the determination device 19 as a load signal. Further, when the heating and stirring of the radioactive waste liquid are started, the air in the evaporator 2 and the vapor of the radioactive waste liquid are drawn out as the exhaust gas by operating the vacuum evacuation device 11. This gas flows into the condenser 9 via the exhaust pipe 6 and is cooled in the condenser 9. As a result, most of the vapor in the gas is condensed, and the condensed liquid dropped is discharged to the condensed liquid tank 15 via the drain pipe 10b. On the other hand, the non-condensable gas component is sucked by the vacuum exhaust device 11 and discharged to the off-gas system. Then, the condensed liquid from the condenser 9 is stored in the condensed liquid tank 15.

The level of the condensed liquid stored in the condensed liquid tank 15 is detected by a liquid level gauge 17. This detection value is used as a liquid level signal as the determination device 19 and the heating control device 4.
3 is output. In the heating control device 43, the liquid level signal is differentiated to determine the rising speed of the liquid surface, and the heating steam supply amount from the heating device 20 is controlled such that the rising speed becomes a predetermined value. Thereby, the evaporation rate of the radioactive waste liquid in the evaporator 2 by the heating device 20 is maintained at a desired evaporation speed, so that even if the heating device 20 has a failure or a setting mistake, for example, it can be removed by excessive heating. A reduction in dyeing efficiency is prevented.

On the other hand, in the determination device 19, the output timing of the opening signal is determined based on the weight signal of the load cell 21 and the load signal of the load detector 8. That is, the weight signal is taken in as an indication of the weight (residual amount) of the radioactive waste liquid whose concentration has been increased while evaporating in the evaporator 2, and is compared with the first comparison value in the first comparison unit. Further, the load signal is taken in as an indication of the viscosity of the radioactive waste liquid that has increased with the concentration increase, and is compared with the second comparison value in the second determination unit. Further, the liquid level signal is taken as an indication of the amount of water removed from the radioactive waste liquid,
The judgment is compared with the third comparison value.

The results of the determinations by the first to third determination units are output to the opening timing determination unit as comparison signals. And
In the opening timing determination section, the weight (residual amount) is the first
When the load value (viscosity) is equal to or greater than the second comparative value, and the liquid level (moisture content) is equal to or greater than the third comparative value,
It is determined that it is the opening timing of the dispensing device 22, and the opening information indicating this is notified to the operator by sound or light. When the above determination result is obtained, the condensate tank 1
The condensed liquid of No. 5 is discharged to the condensed liquid storage, and preparation for concentration of the next lot is performed. If the signal state indicates that the operation is abnormal, the operator is notified of the abnormality information, and the diluent is injected into the evaporator 2 from the diluent pipe 42 so that the radioactive waste liquid in the evaporator 2 is discharged. Is prevented from solidifying.

When the opening timing is recognized by the operator, the suction by the vacuum evacuation device 11 is stopped and the pressure is reduced to a weak negative pressure. The secondary lid 28 shown in FIGS. 3A and 3B and FIG.
By removing the sealing plate 26e of the primary lid 26 in (a) and (b), the solidified container 23 having the upper surface opened is connected to the dispensing device 22. Thereafter, the valve 41 is switched to the open state, and the air in the solidification container 23 is removed from the evaporator 2.
Through the off-gas system. And solidification container 2
When the pressure of the evaporator 2 is equalized to the same level as that of the evaporator 2, the discharging device 22 is opened, and the entire amount of the high-concentration radioactive waste liquid in the evaporator 2 is blown to the solidification container 23 by its own weight ( (Instantaneously). As a result, the radioactive waste liquid concentrated to an extremely high concentration is rapidly cooled and solidified in the solidification container 23, so that a solid having a large strength is generated. Thereafter, the solidification container 23 is separated from the dispensing device 22 and transported to a work place. On the other hand, in the evaporator 2, the above-described series of processes such as charging, heating, stirring, and exhausting are performed on the radioactive waste liquid of the next lot.

The transportation to the work place is performed by handling the hanging tool 201 for the inner grip with respect to the solidification container 23.
As shown in FIG. 11, the hanging tool 201 is attached to a lifting facility such as a hoist, and is located above the solidification container 23 and can be moved up and down. The hook 201 for the solidification container 23 is provided with a cam mechanism including the hanger pins 204 and the link support plate 205 by alternately repeating the locking and releasing of the hooks 203 for automatic stoppers by the vertical movement of the hanging ring 202. The container guide 206 is expanded and contracted to the hook portion 24a extending in the inner circumferential direction from the upper edge of the portion 24, and the solidified container 23
Is to be mounted. Thereafter, the solidification container 23 is lifted and transported using a hoist or other lifting equipment. The inside of the hooking portion 24a can be gripped, and the gripping portion of the hanging tool 201 does not protrude beyond the outer diameter of the solidified container 23, so that the container can be handled even on a transport route with limited space. The demounting of the solidification container 23 is performed by opening the container guide 206 from the hook portion 24a on the upper part of the solidification container 23 by the same operation as when the container is mounted.

When the solidification container 23 is transported to the work place,
The sealing plate 26e is placed on the second annular plate 26b of the solidification container 23 by remote control, and the sealing plate 2
The sealing by the primary lid 26 is performed by fastening the 6e and the second annular plate 26b. As shown in FIGS. 9 and 10, when another form of solidification container is used, the sealing plate 126 is used.
e grips the handle 126g with a tool for remote work,
The guide pin 139 is positioned with respect to the annular plate 126a by matching with the guide hole 143. Then, the guide pin 139 is passed through the positioning hole 142 so that the sealing plate 12
6e approaches the annular plate 126a, the bolt member 140 penetrates the guide hole 143, and further the threaded portion 141
To the screw hole 141a. At this position, the bolt member 14
When 0 is rotated, the screw portion 140c is screwed into the screw hole 141a, and the sealing plate 126e is fixed to the annular plate 126a. Thereafter, the secondary lid 28 shown in FIGS. 3A and 3B is fixed to the upper end of the solidification container 23 by remote control as necessary.

The secondary lid 28 is a ring member 2 of the solidification container 23.
If the solidification container 23 is stored at the uppermost stage after being placed on the secondary band 7, the regular band 30 shown in FIG.
8 around. On the other hand, if the solidification container 23 is stored at a position other than the top, the stacking band 31 of FIG. 7 is attached around the secondary lid 28.

When the service band 30 and the stacking band 31 are attached, the tightening member 32 shown in FIGS. 6A and 6B is fastened by the bolt member 33 and the nut member 34, so that the secondary lid 28 is formed. Is fixed to the solidification container 23. As a result, when the solidification container 23 is separated from the evaporator 2,
Even when the radioactive waste liquid adheres to the first annular plate 26a of the primary lid 26 from the evaporator 2, the leakage of the radioactive waste liquid to the outside is reliably prevented by the double lid structure of the secondary lid 28. Further, the bolt member 26f is provided with a retaining pin 33.
At c, the insertion members 32a, 32a are prevented from coming off and do not come off, and no special positioning is required, so that remote operation is possible. Then, the solidified container 23 double-sealed by the primary lid 26 and the secondary lid 28 in this manner is transported to the solidified material storage location and stacked. During this transfer, the solidification container 23 is gripped using a hanging tool that is gripped outside with respect to the ring member 27.

As described above, the method for solidifying the radioactive waste liquid according to the present embodiment, as shown in FIG. 1, converts the radioactive waste liquid containing salts such as boric acid or borate to take in crystal water into the evaporator 2.
, The radioactive waste liquid is stirred and heated, and the radioactive waste liquid is concentrated by extracting gas from the evaporator 2.
It is determined whether or not the radioactive waste liquid has been concentrated to a predetermined concentration based on the load at the time of stirring, the weight of the radioactive waste liquid in the evaporator 2, and the amount of condensate generated from the gas. In this case, the radioactive waste liquid is transferred from the evaporator 2 to the solidification container 23 and solidified. The solidification method is performed by a solidification device having the following configuration.

That is, an evaporator 2 containing a radioactive waste liquid and having a discharge port formed at the bottom, and a dispenser 22 provided with the discharge port of the evaporator 2 openable and closable and connectable to a solidification container 23.
A heating device 20 capable of heating the radioactive waste liquid stored in the evaporator 2 to an arbitrary temperature; a stirring device 7 for stirring the radioactive waste liquid stored in the evaporator 2; Apparatus 11, condenser 9 for cooling gas to generate condensate, condensate tank 15 for storing condensate, load detector 8 for detecting load of stirring device 7, and contained in evaporator 2. Load cell 21 for detecting the weight of waste radioactive liquid
(Weight detector), a liquid level gauge 17 (storage amount detector) for detecting the storage amount of the condensed liquid in the condensed liquid tank 15, and the load of the stirring device 7, the weight of the radioactive waste liquid, and the stored amount of the condensed liquid. And a determining device 19 for determining whether the radioactive waste liquid has been concentrated to a predetermined concentration.

In this embodiment, the condensate tank 15
The liquid level gauge 17 for detecting the stored amount of the condensed liquid in the above is exemplified as a stored amount detector, but the present invention is not limited thereto. It may be a liquid level detector that outputs. In this case, the process of determining the detection signal by the determination device 19 can be omitted by adjusting the detection position of the liquid level by the liquid level detector to a predetermined position.

According to the radioactive liquid solidification method and the solidifying apparatus described above, the radioactive liquid waste is sufficiently concentrated in the evaporator 2 to reduce the volume, and then discharged from the evaporator 2 to the solidification container 23. Within 23, the radioactive waste liquid can be solidified as crystals of the dissolved salt. This eliminates the need to transfer the radioactive waste liquid to each device when reducing the volume of the radioactive waste liquid, so that a large volume reduction can be realized in a short time in a simple operation process. Further, the concentration immediately before the crystal of the dissolved salt precipitates is detected based on the easily detectable parameters such as the load at the time of stirring, the weight of the radioactive waste liquid and the amount of the condensate, and the radioactive waste liquid is detected from the evaporator 2. You can know exactly when to pay out. As a result, it is possible to reliably prevent the radioactive waste liquid from solidifying in the evaporator 2 due to excessive concentration, or to prevent solidification in the solidification container 23 due to insufficient concentration.

In the solidifying device according to the present embodiment, the storage speed detector (the liquid level gauge 17 and the heating control device 43) for detecting the storage speed of the condensed liquid in the condensed liquid tank 15, and the storage speed becomes a predetermined value. As described above, the configuration having the first heating control device (heating control device 43) that controls the heating of the radioactive waste liquid by the heating device 20 prevents contamination of the condensate caused by excessively heating the radioactive waste liquid. It is possible to prevent it.

In this embodiment, the condensate tank 15
Is calculated based on the rising speed of the liquid level.
However, the present invention is not limited to this. A load cell is provided in the condensate tank 15, and the condensate tank 15 obtained from this load cell is provided.
May be determined based on the rate of change of the weight of the object. Further, the solidifying device in the present embodiment may be configured as described below instead of the configuration in which the storage speed of the condensed liquid tank 15 is obtained and the heating device 20 is controlled.

That is, as shown in FIG. 9, the temperature detectors 45a are provided on the inlet side and the outlet side of the cooling water passage of the condenser 9, respectively.
45b, and a flow detector 44 for detecting the flow rate of the cooling water flowing through the cooling water passage. The condenser 9 cools the gas based on the detection signals of the flow detector 44 and the temperature detectors 45a and 45b. The amount of heat consumed by the cooling water used in the process is detected (heat consumption detector). Then, the heating control device 4 is controlled so that the heat consumption becomes a predetermined value (second set value).
6, the heating device 20 may be configured to control the heating of the radioactive waste liquid.

Further, it is desirable that the solidifying apparatus of the present embodiment is provided with an electric conductivity detector (not shown) for detecting the electric conductivity of the condensate generated in the condenser 9. This is for the following reason. That is, when an organic substance is mixed in the radioactive waste liquid, it is foamed in the evaporator 2 under the influence of bubbles due to boiling. Then, the foam grows and the foam itself is exhausted together with the gas from the evaporator 2, thereby contaminating the condensate in the condenser 9 and the condensate tank 15 in the latter stage. Therefore, it is desirable to monitor the foaming state of the radioactive waste liquid in the evaporator 2, but it is difficult to directly monitor the state. Focusing on the property that an increase in the concentration of salt contained in the concentrate particles of radioactive waste liquid increases the electrical conductivity of the condensate, if the electrical conductivity of the condensate is detected by an electrical conductivity detector, This is because the foaming state in the evaporator 2 can be monitored.

[0053]

According to the first aspect of the present invention, after a radioactive waste liquid containing a salt for taking in water of crystallization such as boric acid or a borate is charged into an evaporator, the radioactive waste liquid is stirred and heated, and gas is discharged from the evaporator. To concentrate the radioactive waste liquid,
A method for solidifying a radioactive waste liquid in which a radioactive waste liquid is transferred from an evaporator to a solidification container and solidified when the concentration becomes a predetermined concentration, wherein the load at the time of stirring, the weight of the radioactive waste liquid in the evaporator, and the gas It is configured to determine whether or not the radioactive waste liquid has been concentrated to a predetermined concentration based on the amount of condensed liquid generated from.

According to the above arrangement, the radioactive waste liquid is sufficiently concentrated and reduced in volume in the evaporator, and then discharged from the evaporator to the solidification container, thereby dissolving the radioactive waste liquid in the solidification container. It can be solidified as salt crystals. This eliminates the need to transfer the radioactive waste liquid to each device when reducing the volume of the radioactive waste liquid, so that a large volume reduction can be realized in a short time in a simple operation process.

Further, the concentration immediately before the crystal of the dissolved salt is precipitated is detected on the basis of the easily detectable parameters such as the load at the time of stirring, the weight of the radioactive waste liquid and the amount of the condensate, and the concentration is determined from the evaporator. The timing of dispensing the radioactive liquid waste can be accurately known. As a result, there is an effect that the radioactive waste liquid can be solidified in the evaporator due to excessive concentration, and the problem that the concentration is insufficient and cannot be solidified in the solidification container can be reliably prevented.

According to a second aspect of the present invention, a radioactive waste liquid containing a salt for taking in water of crystallization such as boric acid or borate is concentrated.
An apparatus for solidifying a radioactive waste liquid which is transferred to a solidification container and solidified when the concentration becomes a predetermined concentration, wherein the radioactive waste liquid is accommodated, an evaporator having an outlet formed at a bottom portion, and an outlet of the evaporator. A dispensing device that can be opened and closed and that can be connected to the solidification container, a heating device that can heat the radioactive waste liquid contained in the evaporator at an arbitrary evaporation rate, and agitates the radioactive waste liquid contained in the evaporator. A stirrer, a vacuum evacuation device for drawing gas from the evaporator, a condenser for cooling the gas to generate a condensate, a condensate tank for storing the condensate, and detecting a load on the stirrer. Load detector, a weight detector that detects the weight of the radioactive waste liquid contained in the evaporator, a storage amount detector that detects the storage amount of the condensate in the condensate tank, a load of the stirring device, Weight of radioactive liquid waste It said radioactive liquid waste on the basis of the storage amount of the fine condensate is configured to have a determining unit whether it has been concentrated to a predetermined concentration.

According to the above configuration, the solidifying method according to the first aspect can be realized with a simple device configuration. Then, the volume reduction can be completed in a short time with a simple work process, and the timing of payout can be accurately known.

According to a third aspect of the present invention, there is provided the radioactive waste liquid solidifying apparatus according to the second aspect, wherein a storage speed detector for detecting a storage speed of the condensate in the condensate tank, and wherein the storage speed is a predetermined value. And a first heating control device for controlling the heating of the radioactive waste liquid by the heating device. According to the above configuration, there is an effect that it is possible to reliably prevent a decrease in the decontamination efficiency due to a mistake in the heating amount (evaporation rate) of the radioactive waste liquid by the heating device.

According to a fourth aspect of the present invention, there is provided the radioactive waste liquid solidifying apparatus according to the second aspect, wherein a heat consumption detector for detecting a heat consumption of a cooling medium used for cooling gas in the condenser; A second heating control device that controls heating of the radioactive waste liquid by the heating device so that the heat consumption becomes a predetermined value. According to the above configuration, there is an effect that it is possible to reliably prevent a decrease in the decontamination efficiency due to a mistake in the heating amount (evaporation rate) of the radioactive waste liquid by the heating device.

According to a fifth aspect of the present invention, there is provided an apparatus for solidifying a radioactive liquid waste according to the second aspect, wherein the internal space of the evaporator and the internal space of the solidification vessel from which gas is extracted by the vacuum exhaust device. This is a configuration having a communication mechanism capable of communicating with According to the above configuration, since the pressure in the solidification container and the evaporator can be set to substantially the same pressure, there is an effect that the discharge of the radioactive waste liquid from the evaporator to the solidification container can be surely performed instantaneously.

According to a sixth aspect of the present invention, there is provided the apparatus for solidifying a radioactive waste liquid according to the second aspect, wherein the diluent is connected to the evaporator and can be charged with a diluent for diluting the radioactive waste liquid in the evaporator. This is a configuration having an injection line. According to the above configuration, when an abnormality occurs in the concentration state of the radioactive waste liquid in the evaporator, solidification of the radioactive waste liquid in the evaporator can be prevented by introducing the diluent. As a result, there is an effect that it is possible to avoid the difficult restoration work of removing the solidified matter from the evaporator or dissolving the solidified matter.

According to a seventh aspect of the present invention, there is provided the apparatus for solidifying radioactive waste liquid according to the second aspect, further comprising an electric conductivity detector for detecting the electric conductivity of the condensate generated by the condenser. is there. According to the above configuration, since the foaming state of the radioactive waste liquid in the evaporator can be grasped through the electric conductivity, the concentrate of the radioactive waste liquid is exhausted together with the gas due to the growth of bubbles to contaminate the condensate. This makes it possible to prevent such a problem.

According to an eighth aspect of the present invention, there is provided a solidification container used in the radioactive waste liquid solidifying apparatus according to any one of the second to seventh aspects, wherein the solidification container is connected to the dispensing apparatus.
This is a double lid structure including a secondary lid and a secondary lid that covers the primary lid in a sealed state. According to the above configuration, even when radioactive waste liquid adheres to the primary lid when dispensing from the dispensing device to the solidification container, the primary lid is covered with the secondary lid in a sealed state, so that the solidification is performed. This has the effect of preventing the radioactive waste liquid on the primary lid from leaking to the outside during storage of the container.

According to a ninth aspect of the present invention, there is provided the radioactive waste liquid solidifying apparatus according to the eighth aspect, wherein the volume of the solidification container can accommodate the entire amount of the radioactive waste liquid concentrated to a predetermined concentration in the evaporator. The configuration is set to the degree. According to the above configuration, since all the radioactive waste liquid in the evaporator can be discharged to the solidification container at a burst with a large outflow amount, the radioactive waste liquid is discharged in a small amount as in the case of dispensing a plurality of times. As a result, the solidified material does not remain in the evaporator or in the dispensing device.

According to a tenth aspect of the present invention, there is provided an apparatus for solidifying a radioactive liquid waste according to any one of the second to seventh aspects,
The solidification container includes a cylindrical body, a lid for closing the inside of the body, and a hook extending in an inner circumferential direction from an upper edge of the body. According to the above configuration, the solidification container can be attached / detached and handled by not only the outer grip on the ring member but also the inner grip on the hook portion. As a result, since the container hanger does not protrude other than the outer shape of the solidified container, the container can be handled even on a transport route with a limited space. Also, there is an effect that it is possible to avoid interference with an adjacent solidification container when attaching / detaching the hanging tool.

An eleventh aspect of the present invention is the radioactive waste liquid solidifying apparatus according to the tenth aspect, wherein the hook portion is provided on the entire inner periphery of the upper edge. According to the above configuration, regardless of the direction at the time of gripping the hanging tool,
The solidification container can be grasped from all directions by the inner grasping of the hook portion. As a result, there is an effect that the operation can be effectively performed particularly in a situation where the operability such as a remote operation is limited.

[Brief description of the drawings]

FIG. 1 is a process diagram of a solidifying device.

FIG. 2 is a cutaway view of a part of the solidification container,
(A) is a plan view and (b) is a front view.

FIG. 3 shows a schematic configuration of a secondary lid, and (a)
FIG. 3 is a cross-sectional view taken along line AA ′ in (b), and (b) is a plan view of a secondary lid.

FIG. 4 is a plan view of a service band.

FIG. 5 is an explanatory diagram showing a state in which a regular band is attached to a secondary lid.

FIG. 6 shows a fastening member, where (a) is a side view,
(B) is a front view.

FIG. 7 is a plan view of a stacking band.

FIG. 8 is an explanatory diagram showing an attached state of a band member and a guide fitting.

FIG. 9 is a plan view of a solidification container.

FIG. 10 is a longitudinal sectional view of a body and a primary lid of a solidification container.

FIG. 11 is a process diagram showing handling of the solidification container.

FIG. 12 is a process chart of a solidifying device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 2 Evaporator 4 Waste liquid piping 5 Additive piping 6 Exhaust piping 7 Stirring device 8 Load detector 9 Condenser 11 Vacuum exhaust device 12 Fan 13 Vacuum tank 15 Condensed liquid tank 16 Circulation path 17 Liquid level gauge 19 Judging device 20 Heating device 21 Load cell 22 Dispensing device 23 Solidification container 24a Hook portion 26 Primary lid 28 Secondary lid 30 Service band 31 Stacking band 32 Tightening member 40 Communication pipe 41 Valve 42 Diluent pipe 43 Heat control device 44 Flow rate detector 46 Heating control device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G21F 9/16 521 G21F 9/16 521D (72) Inventor Yoshiaki Tanaka 4-chome Bingo-cho, Chuo-ku, Osaka-shi, Osaka No. 1-3 Kobe Steel, Ltd. Osaka Branch Office (72) Inventor Toshikatsu Watanabe 4-3-1 Bingo-cho, Chuo-ku, Osaka-shi, Osaka F-term 4D034 AA24 BA01 CA12 4D076 AA08 AA22 AA24 BB13 CA01 CD12 CD22 DA10 EA02X EA04X EA05X EA07X EA11X EA13X EA13Y EA15X EA19X HA13 JA01 JA02 JA03

Claims (11)

[Claims] 1. A radioactive waste liquid containing a salt for taking in water of crystallization such as boric acid or borate is charged into an evaporator, and the radioactive waste liquid is stirred and heated, and a gas is extracted from the evaporator to remove the radioactive waste liquid. Concentrating, a radioactive waste liquid solidification method in which the radioactive waste liquid is transferred from the evaporator to a solidification container when the concentration becomes a predetermined concentration, and solidified, wherein the load at the time of stirring and the weight of the radioactive waste liquid in the evaporator are Determining whether or not the radioactive waste liquid has been concentrated to a predetermined concentration based on the amount of condensate generated from the gas. 2. A radioactive waste liquid solidifying apparatus comprising: concentrating a radioactive waste liquid containing a salt for taking in water of crystallization such as boric acid or borate; transferring the solid waste to a solidification container when a predetermined concentration is reached; An evaporator containing the radioactive waste liquid and having an outlet formed at the bottom, an outlet of the evaporator provided so as to be openable and closable, and a dispensing device connectable to the solidification container; A heating device capable of heating the radioactive waste liquid at an arbitrary evaporation rate; a stirring device for stirring the radioactive waste liquid contained in the evaporator; a vacuum exhaust device for extracting gas from the evaporator; and cooling and condensing the gas A condenser that generates a liquid; a condensate tank that stores the condensate; a load detector that detects a load on the stirring device; and a weight detector that detects the weight of the radioactive waste liquid contained in the evaporator. The condensation A storage amount detector for detecting a storage amount of the condensed liquid in the tank; and determining whether or not the radioactive waste liquid has been concentrated to a predetermined concentration based on a load of the stirring device, a weight of the radioactive waste liquid, and a stored amount of the condensed liquid. An apparatus for solidifying a radioactive liquid waste, comprising: a determination device. 3. A storage speed detector for detecting a storage speed of the condensed liquid in the condensed liquid tank, and a first heating control for controlling heating of the radioactive waste liquid by the heating device so that the stored speed becomes a predetermined value. The apparatus for solidifying a radioactive liquid waste according to claim 2, comprising an apparatus. 4. A heat consumption detector for detecting heat consumption of a cooling medium used for cooling gas in the condenser; and heating the radioactive waste liquid by the heating device so that the heat consumption becomes a predetermined value. The apparatus for solidifying a radioactive waste liquid according to claim 2, further comprising a second heating control device for controlling. 5. The radioactivity according to claim 2, further comprising a communication mechanism capable of communicating an internal space of the evaporator from which gas is drawn by the vacuum exhaust device and an internal space of the solidification container. Waste liquid solidification device. 6. The apparatus for solidifying a radioactive waste liquid according to claim 2, further comprising a diluent injection line connected to the evaporator and capable of introducing a diluent for diluting the radioactive waste liquid in the evaporator. . 7. The apparatus for solidifying a radioactive liquid waste according to claim 2, further comprising an electric conductivity detector for detecting electric conductivity of the condensate generated in the condenser. 8. The solidification container has a double lid structure including a primary lid connectable to the dispensing device, and a secondary lid that covers the primary lid in a sealed state. An apparatus for solidifying a radioactive liquid waste according to any one of claims 2 to 7. 9. The radioactive waste liquid according to claim 8, wherein a volume of the solidification container is set to an amount capable of accommodating the entire amount of the radioactive waste liquid concentrated to a predetermined concentration in the evaporator. Solidification equipment. 10. The solidification container, comprising: a cylindrical body;
8. The apparatus according to claim 2, further comprising: a lid that closes an upper part of the inside of the body, and a hook that extends in an inner circumferential direction from an upper edge of the body. 9. Equipment for solidifying radioactive liquid waste. 11. The apparatus for solidifying radioactive liquid waste according to claim 10, wherein the hook portion is provided on the entire inner periphery of the upper edge.