JP4421643B2 - Resin discharging structure and discharging method of ion exchange resin tower - Google Patents

Description

  The present invention relates to a resin discharge structure and a discharge method for an ion exchange resin tower in chemical decontamination work using piping and equipment such as power plant facilities as chemical decontamination objects.

  In general, for example, at a nuclear power plant, a work called chemical decontamination is performed to reduce the radiation dose to piping equipment, etc., and to reduce the radiation exposure to regular inspection workers before the start of the periodic inspection work of equipment. .

  For example, chemical decontamination work in a pipe is performed by dissolving and removing an oxide film accompanied by radioactive contamination in the pipe with a chemical. In addition, components dissolved in the decontamination solution, that is, metal ions and chemicals in the oxide film accompanied by radioactive contamination dissolved and removed by chemicals, are exchanged with ion exchange resin towers (hereinafter referred to as resin towers). (Hereinafter referred to as “resin”). The used resin that has adsorbed the oxide film is stored and stored in a state where it is filled in the resin tower, and then discharged to, for example, a resin storage tank.

  In a general resin tower structure, a cylindrical resin tower main body is housed in a shielding container, and an upper lid is provided at the upper end opening portion and a flat bottom plate is provided at the lower end opening portion. An upper screen is provided on the lower surface of the upper lid, and a mortar-shaped lower screen is provided on the upper surface of the bottom plate. The resin tower body is filled with resin to form a resin layer.

  An upper nozzle that passes through the upper lid from above is attached to the upper lid, and a valve is attached to the upper nozzle. A lower nozzle is provided in the gap between the bottom of the lower screen and the bottom plate. One end of the lower nozzle passes through the bottom plate and the side surface of the resin tower main body, and a valve is attached outside the resin tower main body. Further, a resin discharge nozzle is attached to the lower end portion of the lower screen, and the resin discharge valve is attached outside the resin tower main body through the bottom plate and through the side surface of the resin tower main body in the same manner as the lower nozzle.

  When the resin to be filled as the resin layer is a cationic resin, the decontamination liquid at the time of the chemical decontamination work flows into the resin tower body from the lower nozzle, and passes through the lower screen and the resin layer to pass through the decontamination liquid. The treated water that has recovered the metal ions and passed through the resin layer flows out from the upper screen to the upper nozzle, and is reused, for example, as cleaning water for the object to be decontaminated. When the resin to be filled is used in a mixture of a cation resin and an anion resin, the flow of water containing decontamination is opposite to that described above (from the upper nozzle to the lower nozzle).

The used resin from which the oxide film has been collected is discharged from the resin tower body after the completion of the chemical decontamination work. In that case, after closing the lower nozzle, water or compressed air is injected into the resin tower body from the upper nozzle to extrude the resin layer, and it flows out from the resin discharge nozzle at the lower end of the mortar-shaped lower screen and connects to the resin discharge valve It is discharged to, for example, a resin storage tank outside the resin tower through a pipe (not shown). (For example, refer to Patent Document 1).
JP 2000-206293 A

  However, in the above-described conventional resin discharging structure and discharging method from the resin tower, since a part of the nozzle for taking in and out the decontamination liquid and the resin discharging nozzle are provided in the lower part of the resin tower, the height of the tower is high. This increases the weight of the resin tower, increases the position of the center of gravity of the resin tower, and reduces the portability within the power plant due to the height restriction.

  In addition, in the conventional resin tower, water accumulated below the resin discharge nozzle attached to the lower end of the lower screen cannot be discharged, and tens of liters of water contaminated in contact with the used resin remains. There is also a problem that it remains in the resin tower as water. In addition, since the nozzle for removing and supplying the decontamination solution and the resin discharge nozzle are installed on the side of the resin tower body, it is necessary to make the shielding container into a divided structure, and the shielding is sufficient due to the increase in manufacturing man-hours and processing accuracy. There is a risk of disappearing.

  The present invention has been made in consideration of the above-described circumstances, and reduces the tower height of the resin tower, reduces the tower weight, and improves the safety and portability during movement. And to provide a discharge method.

  Another object of the present invention is to reduce contaminated residual water, simplify the shielding container by changing the structure, and reduce the exposure amount of workers by improving shielding reliability.

  Still another object of the present invention is to provide a resin discharge structure for an ion exchange resin tower capable of providing a reduction in radiation exposure of construction workers by reliably discharging used high-activation resin in the resin tower, and To get a discharge method.

In order to solve the above-described problems, a resin discharge structure and discharge method for an ion-exchange resin tower according to the present invention is a decontamination method that chemically decontaminates piping and equipment such as power plant equipment as described in claim 1. In an ion exchange resin tower for adsorbing and filtering a dye liquor with an ion exchange resin, a shielding device, a shielding lid for closing an upper end opening of the shielding container, a resin tower body housed in the shielding container, and the resin tower An upper lid that closes the upper end opening of the main body, and an inlet nozzle and an outlet nozzle in which the upper end extends through the upper lid and the shielding lid and extends outside the shielding container, and allows the decontamination liquid to be taken in and out of the resin tower body. When, which upper end through the upper lid and the shielding lid extending out of the shielding container, and a resin injection nozzle and the resin discharge nozzle and out of the ion-exchange resin A.

  Further, in order to solve the above-described problem, as described in claim 2, a dish-shaped end plate-shaped bottom plate portion is provided at the lower end of the resin tower main body, and the resin discharge nozzle is disposed immediately above the deepest portion of the bottom plate portion. A lower end opening is disposed, a cylindrical lower screen is provided above the bottom plate portion, and a mortar-shaped resin collecting plate is connected to the upper portion.

  Furthermore, in order to solve the above-described problem, as described in claim 3, the lower end portion of the resin discharge nozzle is formed in a trumpet shape.

  Furthermore, in order to solve the above-described problem, as described in claim 4, a direction perpendicular to the radial direction of the resin tower main body is formed by bending the lower end portion of the inlet nozzle into a substantially L shape in a side view. It is made to open toward.

  And in order to solve the subject mentioned above, as described in Claim 5, the process of connecting the supply source of water and compressed air to the outlet valve of the above-mentioned outlet nozzle via temporary piping or a hose, and the resin storage tank And a step of connecting the resin treatment pipe to the resin discharge valve of the resin discharge nozzle via a resin discharge temporary pipe or hose, a step of closing the inlet valve of the inlet nozzle, an outlet valve of the outlet nozzle and the resin outlet Opening the valve and draining the used resin from the resin discharge nozzle by pouring water into the resin tower main body from the outlet valve of the outlet nozzle, and the used resin when the used resin is discharged And the step of stopping water injection from the outlet valve of the outlet nozzle after confirming that it is not present in the resin discharge nozzle, and the resin from the outlet valve of the outlet nozzle Compressed air flows into the main body, the process of discharging the water in the resin tower main body from the resin discharge nozzle, the residual water in the resin tower main body is confirmed, and the compressed air is discharged when all the residual water is discharged. And the step of stopping the inflow of.

  According to the resin discharge structure and discharge method of an ion exchange resin tower according to the present invention, it is possible to reduce the tower height of the resin tower, so that the weight of the resin tower is reduced, the position of the center of gravity of the resin tower is lowered, and the resin tower Portability can be improved.

  In addition, it is possible to reduce the amount of exposure of workers due to reduction of contaminated residual water, simplification of shielding containers due to structural changes, and improvement in reliability of shielding performance.

  Furthermore, since the used highly activated resin in the resin tower can be reliably discharged, the radiation exposure of construction workers can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of an ion exchange resin tower to which the present invention is applied. FIG. 2 is a view taken in the direction of arrow II in FIG. 1 (a top view of the ion exchange resin tower). 3 is a cross-sectional view taken along line III-III in FIG. As shown in FIGS. 1, 2 and 3, an ion exchange resin tower 1 (hereinafter referred to as a resin tower) is a cylinder formed of, for example, stainless steel in a shielding container 2 formed of, for example, a steel plate or a lead plate. A resin tower main body 3 having a shape is accommodated, and the upper opening of the shielding container 2 is closed by a shielding lid 4. The upper end opening of the resin tower body 3 is closed by the upper lid 5, and a dish-shaped end plate-shaped bottom plate part 6 is connected to the lower end of the resin tower body 3.

  A lower screen 7 having a cylindrical shape having a diameter smaller than that of the resin tower body 3 is provided on the bottom plate portion 6 on a concentric circle in plan view with the resin tower body 3. A mortar-shaped resin collecting plate 8 is provided extending obliquely upward toward the inner peripheral surface.

  A tubular inlet nozzle 9 extending in the vertical direction is disposed in the resin tower body 3. The upper end portion of the inlet nozzle 9 penetrates the upper lid 5 and the shielding lid 4 and extends outside the shielding container 2 (outside the shielding lid 4). An inlet valve 10 is provided at the upper end portion of the inlet nozzle 9, and the lower end portion It passes through the mortar-shaped resin collecting plate 8 and extends toward the vicinity of the upper portion of the bottom plate portion 6 and opens to the outer peripheral portion of the lower screen 7. As shown in FIG. 3 and FIG. 4 which is an enlarged side view of the lower end portion of the inlet nozzle 9, the lower end portion of the inlet nozzle 9 is bent in a substantially L shape in the horizontal direction when viewed from the side. It opens toward the direction orthogonal to the radial direction of, ie, the circumferential direction.

  On the other hand, an upper screen 11 having a cylindrical shape smaller in diameter than the resin tower body 3 is provided on the lower surface of the upper lid 5, and a lower end portion of a tubular outlet nozzle 12 is connected to the upper portion of the upper screen 11. An upper end portion of the outlet nozzle 12 extends through the upper lid 5 and the shielding lid 4 and extends outside the shielding container 2 (outside the shielding lid 4), and an outlet valve 13 is provided at the upper end portion of the outlet nozzle 12.

  On the other hand, for example, as shown in FIG. 2, a tubular resin charging nozzle 14 extending in the vertical direction is disposed in the resin tower body 3. The upper end portion of the resin charging nozzle 14 extends through the upper lid 5 and the shielding lid 4 and extends outside the shielding container 2 (outside the shielding lid 4), and a resin inlet valve 15 is provided at the upper end portion of the resin charging nozzle 14. In addition, as resin with which the resin tower body 3 is filled as the resin layer 16, a cation resin or a mixture of the cation resin and an anion resin is generally used.

  A tubular resin discharge nozzle 17 extending in the vertical direction is disposed in the resin tower body 3. The upper end portion of the resin discharge nozzle 17 passes through the upper lid 5 and the shielding lid 4 and extends outside the shielding container 2 (outside the shielding lid 4). A resin outlet valve 18 is provided at the upper end portion of the resin discharge nozzle 17. The lower end portion is opened directly above the central portion, which is the deepest portion, of the bottom plate portion 6 having a dish-shaped end plate shape. Further, as shown in FIG. 5, which is an enlarged view of the lower end portion of the resin discharge nozzle 17, the lower end portion of the resin discharge nozzle 17 is formed in a trumpet (bell mouth) shape 19.

  Next, the operation of this embodiment will be described.

  The decontamination liquid at the time of the chemical decontamination work flows into the resin tower body 3 from the inlet nozzle 9 and passes through the upper screen 11 and the resin layer 16 so that metal ions in the decontamination liquid are recovered by the resin. The treated water that has passed through the layer 16 flows out from the lower screen 7 to the outlet nozzle 12 and is reused, for example, as washing water for the object to be decontaminated.

  On the other hand, the used resin from which the oxide film has been collected is discharged from the resin tower body 3 after the chemical decontamination work is completed. Here, one Embodiment of the resin discharge method in the resin tower 1 structure of this invention is described using FIG.

  First, the water and compressed air supply source 20 is connected to the outlet valve 13 of the outlet nozzle 12 via a temporary pipe or hose 21. Further, the resin storage tank and the resin processing pipe 22 are connected to the resin outlet valve 18 of the resin discharge nozzle 17 via a resin discharge temporary pipe or a hose 23. Then, the inlet valve 10 of the inlet nozzle 9 is closed.

  Next, the outlet valve 13 and the resin outlet valve 18 of the outlet nozzle 12 are opened, and water is poured into the resin tower body 3 from the outlet valve 13 of the outlet nozzle 12. By this water injection, the resin and water forming the resin layer 16 in the resin tower body 3 are replaced, and the used resin is discharged from the resin discharge nozzle 17.

  When it is confirmed that the used resin activated by the radiation monitor (not shown) does not exist in the resin discharge nozzle 17 when the used resin discharge operation is completed, the outlet valve 13 of the outlet nozzle 12 is used. Stop water injection.

  Next, compressed air flows into the resin tower main body 3 from the outlet valve 13 of the outlet nozzle 12, and water in the resin tower main body 3 is discharged from the resin discharge nozzle 17. The sound of the water flowing through the resin discharge nozzle 17, the pressure inside the resin tower body 3, and the residual water in the resin tower body 3 are confirmed by a radiation monitor, and the inflow of compressed air is stopped when all the remaining water is discharged.

  Conventionally, a part of the nozzle for removing and supplying the decontamination liquid and the resin discharge nozzle 17 which are provided at the lower part of the resin tower 1 are abolished, and all the nozzles, that is, the inlet nozzle 9, the outlet nozzle 12, the resin charging nozzle 14 and the resin discharging nozzle. By providing the nozzle 17 so as to extend upward from the resin tower body 3 and penetrate the upper lid 5 and the shielding lid 4, the height of the resin tower 1 can be reduced.

  As a result, the weight of the resin tower 1 can be reduced, the center of gravity of the resin tower 1 can be lowered, and the portability of the resin tower 1 can be improved. In addition, it is possible to reduce the amount of exposure of workers due to reduction of contaminated residual water, simplification of the shielding container 2 by structural change, and improvement in reliability of shielding performance. Furthermore, since the used highly activated resin in the resin tower body 3 can be surely discharged, it is possible to reduce the radiation exposure amount of construction workers.

  On the other hand, the mortar-shaped lower screen 7 provided in the conventional resin tower 1 is abolished, the cylindrical lower screen 7 is provided at the bottom in the resin tower body 3, and the mortar-shaped resin collecting plate 8 is connected to the upper part. As a result, as compared with the conventional mortar-shaped lower screen, the cylindrical lower screen 7 can easily ensure the processing accuracy and can simplify the manufacturing process.

  Furthermore, by eliminating the flat plate-shaped bottom plate provided in the conventional resin tower 1 and providing the plate-shaped end plate-shaped bottom plate portion 6, the used highly activated resin can be locally accumulated in the deepest portion, and the resin The discharge efficiency by the discharge nozzle 17 can be increased. In particular, if the lower end portion of the resin discharge nozzle 17 is formed in a trumpet (bell mouth) shape 19, the flow velocity in the vicinity of the lower end portion of the resin discharge nozzle 17 is increased, and the resin discharge efficiency by the resin discharge nozzle 17 can be further increased.

  By the way, in embodiment mentioned above, although the example which discharges | emits resin in the state which closed the inlet valve 10 of the inlet nozzle 9 was shown, FIG. 7 which is 2nd embodiment of the resin discharge method in the resin tower structure of this invention is shown. As shown, a temporary pipe extending from a water and compressed air supply source 20 or another temporary pipe or hose 24 branched from a hose 21 is provided, and this temporary pipe or hose 24 is connected to the inlet valve 10 of the inlet nozzle 9. If water can be poured into the resin tower body 3 also from the inlet nozzle 9, the resin discharge efficiency can be further increased.

  In particular, the lower end portion of the inlet nozzle 9 is bent in a substantially L shape in the horizontal direction when viewed from the side, and the inlet nozzle 9 is opened in the direction orthogonal to the radial direction of the resin tower body 3, that is, in the circumferential direction. The water flowing in from 9 flows in a spiral shape toward the central portion of the bottom plate portion 6 having a dish-shaped end plate shape, that is, the deepest portion (see FIG. 3). It leads to a lower end part, and it can raise the discharge efficiency of resin further. In addition, the same code | symbol was attached | subjected to the same component as what was shown in 1st embodiment, and description was abbreviate | omitted.

The longitudinal section of the ion exchange resin tower which shows one embodiment of the resin discharge structure of the ion exchange resin tower concerning the present invention, and the discharge method. The II arrow line view of FIG. 1 (top view of an ion exchange resin tower). 3 is a sectional view taken along line III-III in FIG. The enlarged side view of an inlet nozzle lower end part. The enlarged view of the lower end part of the resin discharge nozzle. The figure which shows 1st embodiment of the resin discharge method in the resin tower in this invention. The figure which shows 2nd embodiment of the resin discharge method in the resin tower in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion exchange resin tower 2 Shielding container 3 Resin tower main body 4 Shielding lid 5 Top cover 6 Bottom plate part 7 Lower screen 8 Resin collecting plate 9 Inlet nozzle 10 Inlet nozzle inlet valve 11 Upper screen 12 Outlet nozzle 13 Outlet nozzle outlet valve 14 Resin Inlet nozzle 15 Resin inlet valve 16 Resin layer 17 Resin outlet nozzle 18 Resin outlet valve 19 Trumpet (bell mouth) shape 20 Water and compressed air supply source 21 Temporary piping or hose 22 Resin storage tank and resin processing piping 23 Resin discharging temporary piping Or hose 24 Temporary piping or hose

Claims (5)

In an ion exchange resin tower that adsorbs and filters a decontamination solution obtained by chemically decontaminating piping and equipment such as power plant facilities with an ion exchange resin,
A shielding device,
A shielding lid for closing the upper end opening of the shielding container;
A resin column body housed in the shield container,
An upper lid for closing the upper end opening of the resin tower body;
An inlet nozzle and an outlet nozzle that have an upper end extending through the upper lid and the shielding lid and extending out of the shielding container, and taking the decontamination liquid into and out of the resin tower body;
An ion exchange resin tower characterized in that an upper end portion extends outside the shielding container through the upper lid and the shielding lid, and includes a resin charging nozzle and a resin discharging nozzle for taking in and out the ion exchange resin. Resin discharge structure. A bottom plate portion having a dish-shaped end plate shape is provided at the lower end of the resin tower main body, and the lower end opening of the resin discharge nozzle is disposed immediately above the deepest portion of the bottom plate portion, and a cylindrical lower screen is provided above the bottom plate portion. The resin discharge structure of an ion exchange resin tower according to claim 1, wherein a resin collecting plate having a mortar shape is connected to the upper portion thereof. The resin discharge structure of an ion exchange resin tower according to claim 1 or 2, wherein a lower end portion of the resin discharge nozzle is formed in a trumpet shape. The resin of the ion exchange resin tower according to claim 1, 2, or 3, wherein the lower end portion of the inlet nozzle is bent in a substantially L shape in a side view and opened in a direction orthogonal to the radial direction of the resin tower body. Discharge structure. A step of connecting a supply source of water and compressed air to the outlet valve of the outlet nozzle through a temporary pipe or hose, and a resin storage tank and a resin processing pipe through the resin discharge temporary pipe or hose. The step of connecting to the discharge valve, the step of closing the inlet valve of the inlet nozzle, the outlet valve of the outlet nozzle and the resin outlet valve are opened, and water is poured into the resin tower body from the outlet valve of the outlet nozzle. The step of discharging the used resin from the resin discharge nozzle and after confirming that the used resin does not exist in the resin discharge nozzle at the time when the used resin discharge operation is completed, from the outlet valve of the outlet nozzle A step of stopping the water injection, and compressed air is introduced into the resin tower main body from the outlet valve of the outlet nozzle, and the water in the resin tower main body is discharged from the resin discharge nozzle. The method comprises: a step of discharging from the tank, and a step of confirming the residual water in the resin tower main body and stopping the inflow of compressed air when all the residual water is discharged. A resin discharge method using the resin discharge structure of the ion exchange resin tower according to 2, 3 or 4.

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