JP5665106B2 - Radioactive waste storage tank lining stripping device - Google Patents

Description

The present invention is, for example, relates to lining peeling HanareSo location for stripping lining applied to the inner surface of the radioactive waste storage tanks contaminated with radionuclides of nuclear power plants.

  For example, the inner surface of a tank that stores radioactive waste such as waste liquid and sludge generated at a nuclear power plant is lined with a rubber or plastic material for the purpose of preventing corrosion of a metal that is a base material of the tank.

  By the way, the lining applied to the inner surface of the radioactive waste storage tank is renewed due to periodic inspection of the inner surface of the tank or deterioration of the lining. Prior to this replacement, all the old lining is peeled off from the inner surface of the tank. It needs to be removed.

  Therefore, since the surface of the lining applied to the inner surface of the radioactive waste storage tank is in contact with waste liquid and sludge containing radioactive nuclides for a long period of time, a large amount of radioactive nuclides adheres to this and the high radiation dose. It has become a rate.

  As a method for peeling such a lining, a method has been conventionally employed in which radioactive substances are fixed on the surface of the lining and an operator enters a tank having a high radiation dose rate and the lining is peeled off by a scraper method or a sand blast method. ing.

  However, in the above peeling method, it is necessary to take measures to protect the worker from radioactive substances in order for the worker to enter the tank, and the worker uses an airline mask so as not to inhale radioactive fine particles. It was necessary to wear anorak to prevent radioactive substances from adhering to the body, which was a work in a poor environment.

  The scraper method used for lining stripping requires a long time for stripping because the lining is hard, and many workers are exposed to radiation, requiring a large number of substitutes to comply with legal radiation dose limits. However, there is a problem that it is difficult to completely remove the lining. In addition, the sandblasting method is not as bad as the scraper method, and a larger amount of sand used as a blasting material in addition to the peeled lining material is generated as radioactive waste. Measures to prevent expansion are necessary.

Therefore, in Patent Document 1, a support column is erected at the center of the tank, and a circular carriage is provided on the support column so as to be movable up and down, a turning carriage is provided on the carriage, and a high-pressure water injection nozzle is provided on the turning carriage. An installed tank wall surface peeling apparatus has been proposed. According to the tank wall surface peeling apparatus, the lining of the tank wall surface is peeled off by rotating the turning carriage horizontally along the outer periphery of the circular carriage while injecting high pressure water from the high pressure water injection nozzle. With one rotation, the carriage can be moved along the column to peel off the lining on the entire inner wall of the tank, so that there is no need for an operator to enter the tank during the work.

  However, in the tank wall surface peeling apparatus proposed in Patent Document 1, it is necessary to stand a support column that supports the carriage so that it can be raised and lowered at the center of the tank. In addition to an increase in the size of the swivel cart that rotates horizontally along the outer periphery of the tank, the size of the apparatus increases, and it is not possible to flexibly handle tanks of different sizes.

The present invention has been made in view of the above problems, and the intended process is to safely protect the lining applied to the inner surface of the tank without the operator entering the tank regardless of the size of the tank. and to provide a lining peeling HanareSo location of radioactive waste storage tank that can and peeling workability.

To achieve the above object, the invention according to claim 1 is a device for peeling by high pressure water lining applied to the inner surface of the radioactive waste storage tank,
A guide rail that is divided into a plurality of parts that can be disassembled and assembled, and is vertically disposed at a predetermined distance from the inner wall of the radioactive waste storage tank;
A support mechanism for supporting the guide rail movably in the circumferential direction along the upper edge of the radioactive waste storage tank via a roller rolling along the upper surface and the inner and outer surfaces of the upper end of the radioactive waste storage tank;
A nozzle unit supported by the guide rail so as to be movable up and down;
Detecting means for detecting an upper limit and a lower limit of the nozzle unit;
An elevating mechanism for elevating and lowering the nozzle unit along the guide rail,
A work of peeling over the lining to a predetermined width of the nozzle unit is moved up and down along the guide rail by the temperature descending Organization while injecting high pressure water from the nozzle unit, the guide rail the nozzle unit wherein by repeating the work of moving circumferentially along the upper edge of radioactive waste storage tank, stripped of all of the lining together,
When the detection means detects an upper limit or a lower limit of the nozzle unit, the nozzle unit is automatically stopped or moved in the reverse direction .

According to the invention of claim 1 Symbol placement, a lining applied to the inner peripheral wall of the radioactive waste storage tank by lifting movement of the nozzle unit along the guide rail while spraying the high-pressure water by the nozzle unit to a predetermined width It can be peeled up and down. After that, the guide rail supported by the upper end edge of the radioactive waste storage tank by the support mechanism is moved along the upper end edge of the tank along with the nozzle unit in the circumferential direction, and the nozzle unit is moved up and down along the guide rail again for lining. Is peeled up and down over a predetermined width, and by repeating these operations, the lining can be peeled off safely and with good workability without entering the tank. This stripping operation is done by moving the guide rails circumferentially along the inside of the inner wall of the tank, so the same equipment can be used for any size radioactive waste storage tank regardless of size. The lining can be peeled off safely and with good workability.

Further, according to the invention of claim 1, wherein, when the nozzle unit is moved up and down movement along the guide rail reaches the upper or lower limit position, this is detected by the detection means the nozzle unit is automatically stopped or reversed Since the nozzle unit is moved in the direction, the nozzle unit does not move beyond the upper limit or lower limit position, and the apparatus can operate stably.

Further, according the invention 2 according to claim 1, since it is possible to divide the guide rails of the long object in a plurality transported by hand to the construction site along with other parts, easily assembled these on the construction site, The handling workability is enhanced.

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

  1 is a side sectional view of a radioactive waste storage tank showing a lining peeling operation by a lining peeling apparatus according to the present invention, FIG. 2 is a view in the direction of arrow A in FIG. 1, and FIG. 4 is an enlarged detailed view of a portion C of FIG. 2, FIG. 5 is an enlarged detailed view of a portion D of FIG. 1, FIG. 6 is an enlarged detailed view of an E portion of FIG. 8 is a cutaway side view of the nozzle unit, FIG. 9 is a view in the direction of arrow G in FIG. 8, FIG. 10 is a view in the direction of arrow H in FIG. 9, and FIG. FIG.

  In FIG. 1, reference numeral 100 denotes a radioactive waste storage tank (hereinafter simply referred to as “tank”) for storing radioactive waste such as waste liquid and sludge generated at a nuclear power plant. The inner surface of the tank 100 is provided with a lining (not shown) of rubber or plastic material for the purpose of preventing corrosion of the metal that is the base material of the tank 100.

  By the way, the lining applied to the inner surface of the tank 100 is newly replaced due to periodic inspection of the inner surface of the tank 100 or deterioration of the lining. Prior to this replacement, all the old lining is removed from the inner surface of the tank 100 by peeling. There is a need.

  Thus, in the present embodiment, the lining peeling operation is performed safely without the operator entering the tank 100 by the lining peeling device 1 shown in FIGS. Hereinafter, the configuration of the lining peeling apparatus 1 will be described.

  As shown in FIGS. 1 and 2, the lining peeling apparatus 1 according to the present invention includes a guide rail 2 that is vertically arranged at a predetermined distance from the inner wall of the tank 100, and the guide rail 2 is used as an upper end edge of the tank 100. A support mechanism 3 that is movably supported in the circumferential direction, a nozzle unit 4 that ejects high-pressure water, and a lifting mechanism 5 that moves the nozzle unit 4 up and down along the guide rail 2 are configured.

  The guide rail 2 is composed of a pair of left and right aluminum-type steel channel members 2A arranged in parallel at a predetermined distance so that the openings face each other, and each channel member 2A has a longitudinal direction (vertical direction). ), And each divided piece 2a is connected by an inlay joint 6.

  The support mechanism 3 supports the guide rail 2 to the upper end edge of the tank 100 so as to be movable in the circumferential direction. As shown in FIG. 4, the guide rail 2 is horizontally attached to the left and right of the upper end. Each of the brackets 7 is supported on the upper edge of the tank 100 so as to be movable in the circumferential direction by rollers 8 rotatably supported by the bracket 7. Further, as shown in FIG. 3, the upper end of the guide rail 2 has rollers 11 rotatably supported by brackets 9 and 10 attached to the upper end of the guide rail 2 on both sides of the upper end of the tank 100. By being sandwiched between the two, it can be securely attached to the tank 100 and its run-out is prevented. Two rollers 11 are provided in the direction perpendicular to the sheet of FIG.

  Further, as shown in detail in FIGS. 5 and 6, the upper ends of the vertical reaction force restraining stays 12 are attached to the left and right of the lower end of the guide rail 2. A function of preventing the swing of the guide rail 2 is achieved by abutting against the existing circulating water pipe 102 arranged in a circle on the bottom.

  The nozzle unit 4 is moved up and down along the guide rail 2 while jetting high-pressure water toward the inner lining of the tank 100, and as shown in FIG. The guide rail 2 is supported so as to be movable up and down. Here, the detail of a structure of the nozzle unit 4 is demonstrated based on FIGS. 8-10.

  Wheels 15 are rotatably supported at four corners of a rectangular base plate 14 of the nozzle unit 4, and an air motor 17 and a water supply body 18 are attached to the base plate 14 via a gear box 16. A rotor 19 extending from the gear box 16 passes through the base plate 14, and a nozzle head 20 is attached to the end of the rotor 19. A lifting tool 21 is attached to the upper end of the gear box 16.

The above air motor 17 and the air supply port 22 and exhaust port 23 is opened, the supply port 22 is connected air supply hose 24 (see FIG. 1) gas extending from the air compressor (not shown), the exhaust port 23 An exhaust hose (not shown) that opens to the atmosphere is connected. A water supply port 25 is opened in the water supply body 18, and a water supply hose 26 (see FIG. 1) extending from a jet pump (not shown) is connected to the water supply port 25. Although not shown, the output shaft of the air motor 17 is connected to the rotor 19 via a reduction gear mechanism (not shown) built in the gear box 16.

  Four nozzles 27 that are inclined by a predetermined angle θ are attached to the nozzle head 20 at equal angular pitches (90 ° pitch) in the circumferential direction, and each nozzle 27 is formed on the nozzle head 20 and the rotor 19. It is connected to a water pump (not shown) through a water supply passage and a water supply hose 24 (see FIG. 1).

  As shown in FIG. 2, the elevating mechanism 5 moves the nozzle unit 4 up and down along the guide rail 2 and is attached to an inverted U-shaped stay 28 attached to the upper end of the guide rail 2. The chain 30 extending vertically downward from the electric chain block 29 is connected to the suspension 21 attached to the gear box 16 of the nozzle unit 4. A variable speed motor with a brake is used as a drive source for the electric chain block 29.

  Further, the guide rail 2 of the lining peeling apparatus 1 according to the present invention is provided with a limit switch 31 for detecting the upper limit of the nozzle unit 4 as shown in FIG. 4, and as shown in FIG. A limit switch 32 for detecting the lower limit of the nozzle unit 4 is provided. In this embodiment, when the limit switches 31 and 32 detect the upper limit and the lower limit of the nozzle unit 4, the nozzle unit 4 is automatically stopped or moved in the reverse direction.

  Further, as shown in FIG. 1, the lining peeling apparatus 1 according to the present invention is provided with a control panel 33 for controlling the electric chain block 29 by remote control. The control panel 33 is connected to the electric chain block by a cable 34. 29 is electrically connected.

  Next, an operation of peeling the lining from the inner peripheral wall of the tank 100 using the lining peeling apparatus 1 configured as described above will be described.

  When removing the lining applied to the inner surface of the tank 100, as shown in FIGS. 1 and 2, the lining peeling device 1 is installed so that the guide rail 2 is located on the inner side from the inner wall of the tank 100. A jet pump (not shown) is driven to supply high-pressure water from the water supply hose 26 to the water supply body 18 of the nozzle unit 4, and an air compressor (not shown) is driven to supply compressed air from the air supply hose 24 to the air motor of the nozzle unit 4. 17 is supplied. Then, the air motor 17 is driven by the compressed air, and the rotation of the output shaft is transmitted to the rotor 19 through a reduction gear mechanism (not shown) built in the gear box 16, and the nozzle head 20 attached to the rotor 19 and While the four nozzles 27 provided on this rotate, the high-pressure water supplied to the water supply body 18 is sprayed from the rotating nozzles 27 toward the lining of the tank 100.

While spraying high-pressure water from each of the four nozzles 27 which rotates as described above, the control panel 33 and remote control to drive the electric chain block 29, if downward along the nozzle unit 4 to the guide rail 2 The lining applied to the inner peripheral wall of the tank 100 is peeled from the upper side to the lower side over a predetermined width. When Nozuruyuni' bets 4 is moved down to the lower limit position, this is detected by the limit switch 32 provided in the nozzle unit 4, together with the informed to the operator by the rotating indicator (not shown) or the like, the nozzle unit 4 is lower While being automatically stopped at the position, injection of high-pressure water from each nozzle 27 is stopped. Alternatively, when the nozzle unit 4 reaches the lower limit position, the electric chain block 29 is reversely driven, the nozzle unit 4 is reversed and raised, and the lining is peeled off by the high pressure water sprayed from each nozzle 27 of the nozzle unit 4. The operator can adjust the ascending / descending speed of the nozzle unit 4 by remotely operating the control panel 33 and controlling the electric chain block 29 according to the peeling state of the lining.

  When the lining applied to the inner peripheral wall of the tank 100 is peeled over a predetermined width as described above, the guide rail 2 supported by the support mechanism 3 so as to be movable at the upper end edge of the tank 100 together with the nozzle unit 4. The nozzle unit 4 is moved up and down along the guide rail 2 again along the upper edge of the tank 100, and the lining is peeled up and down over a predetermined width. In this case, when the nozzle unit 4 reaches the upper limit position, this is detected by a limit switch 31 provided on the guide rail 2 and is notified to the operator by a rotation indicator lamp (not shown). While automatically stopped at the upper limit position, the injection of high-pressure water from the nozzle 27 is stopped.

  Thereafter, the nozzle unit 4 is moved up and down along the guide rail 2 to separate the lining over a predetermined width, and the guide rail 2 is moved together with the nozzle unit 4 along the upper edge of the tank 100 in the circumferential direction. When the guide rail 2 makes one round around the inner peripheral wall of the tank 100 by repeating the above, all of the lining applied to the inner peripheral wall of the tank 100 is peeled off safely and with good workability without the operator entering the tank. .

  Thus, the peeling operation is performed by moving the guide rail 2 in the circumferential direction along the inner side of the inner wall of the tank 100, so that the tank 100 of any size can be used regardless of the size. The same lining peeling apparatus 1 can be used to peel the lining safely and with good workability, and the peeling work can be performed even when a residual liquid is present at the bottom of the tank 100.

  In this embodiment, when the nozzle unit 4 moves up and down along the guide rail 2 and reaches the upper limit or lower limit position, this is detected by the limit switches 31 and 32, and the nozzle unit 4 automatically stops. Since the nozzle unit 4 is configured to move in the opposite direction, the nozzle unit 4 does not move beyond the upper limit or lower limit position, and the lining peeling apparatus 1 can be stably operated.

  Furthermore, in this embodiment, the long guide rail 2 can be divided into three parts and transported by hand to the construction site together with other parts, and these can be easily assembled at the construction site. Is increased.

  When the lining applied to the inner peripheral wall of the tank 100 is peeled as described above, the lining applied to the bottom surface of the tank 100 is then peeled in the manner shown in FIG.

That is, as shown in FIG. 11 , after removing the nozzle unit 4 from the guide rail 2 installed in the tank 100 and removing the electric chain block 29, the limit switches 31, 32, etc., the guide rail 2 is removed from the tank 100. To do.

  Next, the tip of the operation pole 35 is attached to the front and rear of the removed nozzle unit 4, the nozzle unit 4 is hung with a rope or the like and lowered into the tank 100, and the nozzle unit 4 is moved down the wheel 15 as shown in FIG. And movably mounted on the bottom surface of the tank 100. In this state, two workers operate the upper end of the operation pole 35 from outside the tank 100 while jetting high-pressure water from the nozzles 27 (see FIG. 8) of the nozzle unit 4, thereby moving the nozzle unit 4 to the tank 100. The lining applied to the bottom surface of the tank 100 can be peeled off with high-pressure water.

  As a result of the above, all of the lining applied to the inner peripheral wall and the bottom surface of the tank 100 can be peeled safely and with good workability without an operator entering the tank 100. According to the present invention, the lining is peeled off. Is carried out using high-pressure water, so that a large amount of sand used as a blasting material in addition to the separated lining material as in the sandblasting method is not generated as radioactive waste, and the expansion of radioactive contamination around the tank 100 is prevented. be able to.

  Here, the specifications of the tank 100 in the present embodiment are as follows.

・ Type: Open vertical lining tank ・ Contents: Radioactive waste liquid ・ General dimensions: Diameter 4.9m x Height H approx. 7m
・ Material: SM400A (plate thickness t10mm)
・ Lining: Natural rubber lining (thickness t6mm)
Moreover, the specification of the lining peeling apparatus 1 is as follows.

・ High pressure water injection pressure: about 200 MPa
・ Nozzle used: Nozzle diameter: φ0.5mm nozzle x 4 ・ Nozzle angle: inclined by 60 ° with respect to the target surface (inclined by 30 ° from vertical)
・ Nozzle rotation diameter: Diameter φ180mm × 2, φ170mm × 2 (double concentric circles)
・ Nozzle speed: 120rpm (Controlled by pressure and amount of air supplied to air motor)
・ Nozzle lifting speed: 0.2m / min
(Controlled by the speed controller of the electric chain block)
・ Nozzle up / down frequency: 1 to 1.5 reciprocation

  In order to confirm the effect of the present invention, natural rubber was lined with a thickness of 6 mm on an iron plate to obtain a sample for a peel test, and a lining peel test was performed on the sample under the following conditions. The results are shown in Table 1.

  Experimental condition 1: In order to determine the number of nozzles, test No. As a result of performing a lining peeling test under the conditions of 1 and 2, a better result was obtained with four nozzles.

  Experimental condition 2: In order to determine the standoff (distance between the nozzle nozzle and the object), the test No. in Table 1 As a result of performing a lining peeling test under a few conditions, a standoff of 25 mm was better than 50 mm.

  Experimental condition 3: In order to confirm the relationship between the nozzle moving speed and the number of passes, the test No. As a result of performing the lining peeling test under the conditions of 4 to 7, the best result was obtained under the condition that the nozzle moving speed was 350 mm / min and the number of passes was three.

尚、表１において、◎は完全に剥離除去、○はほぼ剥離除去、△は一部残留で不十分、をそれぞれ示す。

In Table 1, “◎” indicates complete removal, “◯” indicates almost removal, and “Δ” indicates that a portion remains and is insufficient.

It is a sectional side view of the radioactive waste storage tank which shows the lining peeling operation | work by the lining peeling apparatus which concerns on this invention. It is a figure of the arrow A direction of FIG. It is the B section enlarged detail drawing of FIG. It is the C section enlarged detail drawing of FIG. FIG. 2 is an enlarged detail view of a D part in FIG. 1. It is the E section enlarged detail drawing of FIG. It is the FF sectional view taken on the line of FIG. It is a fracture side view of a nozzle unit. It is a figure of the arrow G direction of FIG. It is a figure of the arrow H direction of FIG. It is a sectional side view which shows the peeling operation | work of the lining of a radioactive waste storage tank bottom face.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lining peeling apparatus 2 Guide rail 2A Channel material 2a Divided piece of channel material 3 Support mechanism 4 Nozzle unit 5 Lifting mechanism 6 Inlay type joint 7 Bracket 8 Roller 9, 10 Bracket 11 Roller 12 Reaction force restraining stay 13 Roller 14 Base plate 15 Wheel 16 Gearbox 17 Air motor 18 Water supply body 19 Rotor 20 Nozzle head 21 Lifting tool 22 Air supply port 23 Exhaust port 24 Air supply hose 25 Water supply port 26 Water supply hose 27 Nozzle 28 Stay 29 Electric chain block 30 Chain 31, 32 Limit switch (Detection) means)
33 Control panel 34 Cable 35 Operation pole 100 Radioactive waste storage tank 101 Strut 102 Circulating water pipe θ Inclination angle of nozzle

Claims (1)

The lining which has been subjected to the inner surface of the radioactive waste storage tank to a device for peeling by high-pressure water,
A guide rail that is divided into a plurality of parts that can be disassembled and assembled, and is vertically disposed at a predetermined distance from the inner wall of the radioactive waste storage tank;
A support mechanism for supporting the guide rail movably in the circumferential direction along the upper edge of the radioactive waste storage tank via a roller rolling along the upper surface and the inner and outer surfaces of the upper end of the radioactive waste storage tank;
A nozzle unit supported by the guide rail so as to be movable up and down;
Detecting means for detecting an upper limit and a lower limit of the nozzle unit;
An elevating mechanism for elevating and lowering the nozzle unit along the guide rail,
A work of peeling over the lining to a predetermined width of the nozzle unit is moved up and down along the guide rail by the temperature descending Organization while injecting high pressure water from the nozzle unit, the guide rail the nozzle unit wherein by repeating the work of moving circumferentially along the upper edge of radioactive waste storage tank, stripped of all of the lining together,
When the detecting means detects the upper limit or lower limit of the nozzle unit, the nozzle unit is automatically stopped or moved in the reverse direction .

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