JP2011027694A - Decontamination device of facility in nuclear power plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decontamination device of facilities in a nuclear power plant, for effective decontamination in PLR piping such as horizontal assembled piping, without fluctuation of water level of a decontamination liquid. <P>SOLUTION: The decontamination device 1 of facilities in a nuclear power plant includes: a PLR vertical pipe 22 transferring upward a coolant from a recirculation pump 29; a PLR horizontal pipe 23 installed around a nuclear reactor pressure vessel at above the PLR vertical pipe 22; a nuclear reactor recirculation system piping 21 having a PLR riser tube 24 installed above the PLR horizontal pipe 23; a decontamination piping 31 formed in a loop shape for the nuclear reactor recirculation system piping 21; and a temperature control means locally controlling the temperature of at least one of the PLR horizontal pipe 23 and the PLR riser 24. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a chemical decontamination technique in a reactor coolant recirculation system piping (hereinafter referred to as “PLR piping”; PLR; Primary Loop Recycling System), and more specifically, chemical decontamination of horizontal collective piping of PLR piping is possible. The present invention relates to a decontamination apparatus for facilities in a nuclear power plant.

  During the operation of the boiling water nuclear power plant, the recirculation system feed water is supplied with a circulation force by a recirculation pump and then supplied into the reactor through a PLR pipe. The water supplied into the nuclear reactor boils and becomes steam, and this steam is sent to the turbine after moisture is separated, and electric power is generated by rotating the turbine.

  In a nuclear power plant, the plant is periodically stopped, and the piping system including the reactor and the PLR piping is inspected.

  An oxide film such as iron oxide containing a radioactive substance adheres to the inner surface of the PLR pipe. For this reason, the operation | work which removes the oxide film of the inner surface of PLR piping is performed before an inspection so that an operator may not be exposed to an oxide film.

  There are two methods for removing this oxide film: mechanical decontamination method that physically removes the oxide film using a brush, grindstone, ice lump, metal ball, etc., and chemical dissolution that chemically dissolves the oxide film using a reagent or the like. There is a decontamination method. Among them, the chemical decontamination method is suitable for cases where the shape of the object to be decontaminated is complicated, or when it is difficult to remove the object to be decontaminated and the object to be decontaminated is used again after decontamination. It is a dyeing method.

  By the way, generally, in the PLR pipe, a vertical mother pipe (PLR vertical pipe) extending in the vertical direction and a horizontal pipe (PLR horizontal pipe) extending in the horizontal direction from the upper portion of the vertical mother pipe are used. ) And a riser pipe (PLR riser pipe) extending further upward from the horizontal pipe. Of these portions, the horizontal pipe is also called a horizontal collective pipe, and is usually provided in a ring around the reactor pressure vessel. This horizontal collecting pipe cannot remove the decontamination liquid directly from the horizontal collecting pipe, and it is difficult for the decontamination liquid to flow. Therefore, like the straight pipe, the decontamination liquid flows in one direction and always supplies fresh decontamination liquid. Unlike the case, the decontamination efficiency tends to be insufficient. For this reason, various methods have been proposed as decontamination methods for efficiently decontaminating the horizontal collecting pipe.

  For example, in Japanese Patent Laid-Open No. 2005-164344 (Patent Document 1), two pumps are provided in a decontamination pipe connected to a PLR pipe, and the liquid level of the decontamination liquid is raised and lowered by adjusting the flow rate of the pump. A chemical decontamination method for decontaminating horizontal collecting pipes is disclosed.

  Japanese Patent Application Laid-Open No. 2005-69898 (Patent Document 2) provides a heating means for the decontamination pipe connected to the PLR pipe and a blower for blowing air to the vertical mother pipe. A chemical decontamination apparatus and a chemical decontamination method for promoting convection of a dye solution are disclosed.

  Further, in JP-A-8-136696 (Patent Document 3), a decontamination pipe connected to the PLR pipe is provided, and a circulation pump and a heater are arranged in series in this decontamination pipe, so that a decontamination object is provided. A chemical decontamination method for circulating a decontamination solution is disclosed.

  Japanese Patent Laid-Open No. 11-229166 (Patent Document 4) discloses a chemical decontamination apparatus including a cleaning nozzle that is inserted into a PLR pipe and sprays a decontamination liquid.

JP 2005-164344 A Japanese Patent Laid-Open No. 2005-69898 JP-A-8-136696 Japanese Patent Laid-Open No. 11-229166

  However, in the chemical decontamination method described in Patent Document 1, there is a problem that the cost is increased, for example, a pump for circulating the decontamination liquid is installed to change the water level.

  Moreover, in the chemical decontamination method using the chemical decontamination apparatus described in Patent Document 2, the movement of the decontamination liquid in the horizontal collecting pipe provided above the vertical mother pipe cannot be promoted, and the horizontal It does not increase the decontamination efficiency in the collecting pipe.

  Furthermore, the chemical decontamination method described in Patent Document 3 can increase the decontamination efficiency by heating the entire decontamination liquid in the decontamination pipe with a heater provided in the decontamination pipe. It does not control the flow of the decontamination liquid inside. For this reason, this chemical decontamination method is not very effective for improving the decontamination efficiency in the horizontal collecting pipe.

  Further, the chemical decontamination apparatus described in Patent Document 4 is effective for decontamination in a pipe having a simple shape such as a vertical mother pipe, but decontamination in a pipe having a complicated shape such as a horizontal collective pipe. In the case of dyeing, it is difficult to guide the cleaning nozzle to a desired position in the pipe. For this reason, the chemical decontamination method using this chemical decontamination apparatus is not very effective for improving the decontamination efficiency in the horizontal collecting pipe.

  The present invention has been made in view of the above circumstances, and it is possible to remove nuclear power plant facilities that can effectively decontaminate PLR pipes such as horizontal collecting pipes without changing the water level of the decontamination liquid. An object is to provide a dyeing device.

  The present invention has found that when the temperature of at least one of the horizontal collective pipe of the PLR pipe and the pipe in the vicinity thereof is locally controlled, it is possible to effectively decontaminate the horizontal collective pipe and the pipe in the vicinity thereof. It was completed.

  A decontamination apparatus for facilities in a nuclear power plant according to the present invention solves the above-mentioned problems, and a PLR vertical pipe for transferring a coolant from a recirculation pump upward, an atom above the PLR vertical pipe and an atom. A reactor recirculation system pipe having a PLR horizontal pipe installed substantially horizontally around the reactor pressure vessel and a PLR riser pipe installed above the PLR horizontal pipe; And a decontamination pipe formed in a loop shape, and temperature adjusting means for locally adjusting the temperature of at least one of the PLR horizontal pipe and the PLR riser pipe.

  According to the decontamination apparatus for facilities in a nuclear power plant according to the present invention, it is possible to effectively decontaminate a horizontal assembly pipe of a PLR pipe or a pipe in the vicinity thereof.

The figure which shows 1st Embodiment of the decontamination apparatus of the nuclear power plant installation of this invention. FIG. 2 is an enlarged view of a PLR collective piping portion of the decontamination apparatus for facilities in a nuclear power plant shown in FIG. 1. FIG. 3 is an enlarged view of the PLR collective piping section shown in FIG. 2. The enlarged view of the PLR collective piping part which comprises 2nd Embodiment of the decontamination apparatus of the facility in the nuclear power station of this invention. The enlarged view of the PLR collective piping part which comprises 3rd Embodiment of the decontamination apparatus of the facility in the nuclear power station of this invention. The figure which shows 4th Embodiment of the decontamination apparatus of the nuclear power station installation of this invention. FIG. 7 is an enlarged view of a PLR collective piping portion of the decontamination apparatus for facilities in a nuclear power plant shown in FIG. 6. FIG. 7 is an enlarged view of a PLR collective piping portion of the decontamination apparatus for facilities in a nuclear power plant shown in FIG. 6. The figure which shows 5th Embodiment of the decontamination apparatus of the nuclear power plant installation of this invention. The enlarged view of the PLR collective piping part of the decontamination apparatus of the nuclear power plant equipment shown in FIG. The figure which shows 6th Embodiment of the decontamination apparatus of the nuclear power station installation of this invention. FIG. 12 is an enlarged view of a PLR collective piping portion of the decontamination apparatus for facilities in a nuclear power plant shown in FIG. 11.

  A decontamination apparatus for facilities in a nuclear power plant according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a first embodiment of a decontamination apparatus for facilities in a nuclear power plant according to the present invention. FIG. 2 is an enlarged view of the PLR collective piping section 25 of the decontamination apparatus 1 for the facility in the nuclear power plant shown in FIG.

  A decontamination device 1 for facilities in a nuclear power plant shown in FIG. 1 constitutes a part of a nuclear power plant, and includes a nuclear reactor recirculation system pipe 21 and a decontamination device 30.

(Reactor recirculation piping)
The reactor recirculation system pipe 21 is a pipe constituting the reactor recirculation system, and includes a recirculation pump inlet side pipe 27 provided on the inlet (suction) side of the recirculation pump 29 and an outlet of the recirculation pump 29 ( A PLR vertical pipe 22 that extends in a substantially vertical direction from the delivery side and transfers the coolant from the recirculation pump 29 upward, and communicates with the upper end 225 of the PLR vertical pipe 22 and above the PLR vertical pipe 22. A PLR horizontal pipe 23 which is positioned and is installed in a substantially horizontal ring around a reactor pressure vessel (not shown), and a PLR riser pipe 24 which communicates with the pipe wall of the PLR horizontal pipe 23 and extends upward. .

  The PLR vertical pipe 22 serves to circulate feed water (coolant) from the recirculation pump 29 in the nuclear reactor during normal operation of the nuclear power plant including the decontamination device 1 for the facilities in the nuclear power plant. During the decontamination operation, the decontamination liquid is transported toward the upper PLR horizontal pipe 23 and the PLR riser pipe 24.

  The PLR vertical pipe 22 is connected to the branch pipe 221 at a branch point 223 in the middle of the PLR vertical pipe 22. The branch pipe 221 is provided with a decontamination liquid supply port 47 that communicates with the decontamination pipe 31 of the decontamination apparatus 30. For this reason, the PLR vertical pipe 22 communicates with the decontamination pipe 31 of the decontamination apparatus 30 via the branch pipe 221.

  The PLR riser pipe 24 supplies the recirculated water supplied from the PLR horizontal pipe 23 into a reactor pressure vessel (not shown). In FIG. 2, the illustration of the portion of the PLR riser tube 24 following the reactor pressure vessel side is omitted.

  On the surfaces of the PLR horizontal pipe 23 and the PLR riser pipe 24, a heat insulating material such as a heat insulating material is not provided. The reason why the heat insulating material is not provided on the surfaces of the PLR horizontal pipe 23 and the PLR riser pipe 24 is that the outer surfaces of the PLR horizontal pipe 23 and the PLR riser pipe 24 are efficiently used by using temperature control means such as a blower and a heater at the time of decontamination. This is because the circulation speed of the decontamination liquid in the PLR horizontal pipe 23 and the PLR riser pipe 24 is increased by adjusting the temperature well.

  In the present invention, a portion including the PLR vertical pipe 22, the PLR horizontal pipe 23, and the PLR riser pipe 24 in the reactor recirculation pipe 21 is referred to as a PLR collective pipe section 25.

(Decontamination equipment)
The decontamination device 30 is a device that supplies a decontamination liquid to the reactor recirculation system pipe 21. The decontamination liquid injects the decontamination liquid into the decontamination pipe 31 via the decontamination pipe 31 and the injection pipe 36. An injection part 32, a pump 39 for transferring a decontamination liquid in the decontamination pipe 31, a decontamination heater 33 for heating the decontamination liquid in the decontamination pipe 31 to 90 ° C. or more, and a decontamination in the decontamination pipe 31 It has a cation resin tower 34 that removes oxides contained in the dyeing liquid, and a reduction device 35 that decomposes the decontamination liquid in the decontamination pipe 31.

  The decontamination pipe 31 communicates with the decontamination pipe part 311 provided between the decontamination liquid discharge port 48 communicating with the recirculation pump inlet side pipe 27 and the branch part 310, and the branch part 310 and the branch pipe 221. A decontamination pipe part 312 provided between the decontamination liquid supply port 47a and a decontamination pipe provided between the branching part 310 and the decontamination liquid supply port 47b communicating with the recirculation pump inlet side pipe 27. A portion 313.

  That is, the decontamination pipe 31 is composed of an atom by a decontamination liquid supply port 47 a provided in the branch pipe 221 communicating with the PLR vertical pipe 22 and a decontamination liquid discharge port 48 provided in the recirculation pump inlet side pipe 27. Connected to the furnace recirculation piping 21.

  Thereby, in the decontamination apparatus 1 of the facility in the nuclear power plant, the decontamination pipe 31 of the decontamination apparatus 30 and the reactor recirculation system pipe 21 cooperate to form a loop-shaped pipe. The decontamination pipe 31 and the reactor recirculation system pipe 21 form a circulation flow of the decontamination liquid.

  Examples of the decontamination solution used in the present invention include an aqueous potassium permanganate solution in oxidative decontamination, and an aqueous oxalic acid solution and hydrazine in reduction decontamination.

  The decontamination heater 33 can heat the decontamination liquid to 90 ° C. or higher.

  FIG. 2 is an enlarged view of the PLR collective piping section 25 that constitutes the decontamination apparatus 1 for the facility in the nuclear power plant.

  The PLR collective piping section 25 is provided with a blower 51 as temperature adjusting means for locally cooling the outer surface of the PLR riser pipe 24 by blowing air. As the blower 51, a known one can be used. One blower 51 is provided to face each PLR riser pipe 24. In the present invention, the number of fans 51 installed with respect to the PLR riser pipe 24 is not particularly limited, and can be appropriately increased or decreased.

  Next, the effect | action at the time of the decontamination operation | work of the decontamination apparatus 1 of the facility in a nuclear power plant is demonstrated with reference to drawings.

(Introduction of decontamination liquid into PLR vertical pipe, PLR horizontal pipe and PLR riser pipe)
First, the pump 39 of the decontamination apparatus 30 is operated and the decontamination liquid is injected from the decontamination liquid injection part 32, and the decontamination liquid is decontamination heater 33, cation resin tower 34, and reduction apparatus in the decontamination pipe 31. 35 are sequentially transferred, transferred to the PLR vertical pipe 22 through the decontamination liquid supply port 47a and the branch pipe 221, and further from the decontamination liquid discharge port 48 of the recirculation pump inlet side pipe 27 to the decontamination pipe 31. To form a circulating flow of decontamination liquid that returns to

  The high-temperature decontamination liquid transferred into the PLR vertical pipe 22 rises in liquid level by the discharge force of the pump 39 and is sequentially introduced into the PLR horizontal pipe 23 and the PLR riser pipe 24.

  The introduction of the decontamination liquid into the PLR vertical pipe 22, the PLR horizontal pipe 23, and the PLR riser pipe 24 is performed in such a manner that the liquid surface 73 of the high temperature decontamination liquid is in the middle of the PLR riser pipe 24 in the vertical direction. To make it almost constant. The height of the liquid level 73 of the decontamination liquid is adjusted by adjusting the output of the pump 39, the opening degree of the valve in the decontamination apparatus 1 of the facility in the nuclear power plant, and the like.

  When the height of the liquid surface 73 of the decontamination liquid becomes substantially constant, the decontamination liquid in the PLR vertical pipe 22, the PLR horizontal pipe 23, and the PLR riser pipe 24 operates as follows.

(Operation in PLR vertical pipe and PLR horizontal pipe)
<Operation of decontamination liquid flow from the PLR vertical pipe toward the end in the PLR horizontal pipe>
The hot decontamination liquid transferred from the branch pipe 221 into the PLR vertical pipe 22 forms a decontamination liquid flow 68 shown in FIG.

  That is, the decontamination liquid flow 68 forms an upward flow in the PLR vertical tube 22 and forms an upward flow in the PLR horizontal tube 23 toward the end of the PLR horizontal tube 23. In other words, the decontamination liquid flow 68 in the PLR horizontal tube 23 is formed in a direction away from the upper end 225 of the PLR vertical tube 22 in the PLR horizontal tube 23. The upward flow means the flow of the decontamination liquid formed along the upper pipe wall in the PLR horizontal pipe 23.

  The reason why the decontamination liquid flow 68 forms an upward flow in the PLR vertical pipe 22 and an upward flow in the PLR horizontal pipe 23 is that the decontamination liquid constituting the decontamination liquid flow 68 is at the tip of the PLR horizontal pipe 23. This is because the specific gravity is small at high temperature as compared with the decontamination liquid that constitutes the decontamination liquid flow 70 that is folded back to the PLR vertical pipe.

  In the decontamination apparatus 1 of the facility in the nuclear power plant, no heat insulating material or the like is provided on the surface of the PLR horizontal pipe 23. Therefore, the hot decontamination liquid constituting the decontamination liquid flow 68 dissipates more heat as it is transferred in the PLR horizontal pipe 23 than in the case where a heat insulating material or the like is provided on the surface of the PLR horizontal pipe 23. Temperature decreases. In other words, the decontamination liquid stream 68 has a large negative temperature gradient in the PLR horizontal pipe 23 with respect to the moving direction of the decontamination liquid.

  It is preferable that the decontamination liquid stream 68 has a large negative temperature gradient in the PLR horizontal pipe 23 because the flow rate of the circulating flow composed of the decontamination liquid streams 68 and 70 is increased.

  In addition, when the temperature of a decontamination liquid will be less than 80 degreeC, there exists a possibility that a decontamination capability may fall. For this reason, in this invention, it is preferable that the temperature in the front-end | tip part of the PLR horizontal pipe 23 of the high temperature decontamination liquid which comprises the decontamination liquid flow 68 is 80 degreeC or more.

<Operation of decontamination liquid flow from the end in the PLR horizontal pipe toward the PLR vertical pipe>
The decontamination liquid flow 68 is folded back at the tip of the PLR horizontal pipe 23 toward the PLR vertical pipe to form a decontamination liquid flow 70 shown in FIG.

  The temperature of the decontamination liquid constituting the decontamination liquid flow 70 is several times as compared with the temperature when the high temperature decontamination liquid constituting the decontamination liquid flow 68 is transferred from the branch pipe 221 into the PLR vertical pipe 22. It is about ℃ lower.

  The decontamination liquid flow 70 forms a downward flow from the end of the PLR horizontal tube 23 toward the upper end 225 of the PLR vertical tube 22 in the PLR horizontal tube 23, and then enters the PLR vertical tube 22, and enters the PLR vertical tube 22. A downward flow is formed within. The downward flow in the PLR vertical pipe 22 passes through the branch point 223 and is formed toward the recirculation pump 29 side. Here, the downward flow means the flow of the decontamination liquid formed along the lower pipe wall in the PLR horizontal pipe 23.

  The reason why the decontamination liquid flow 70 forms a downward flow in the PLR horizontal pipe 23 and a downflow in the PLR vertical pipe 22 is that the decontamination liquid constituting the decontamination liquid flow 70 constitutes the decontamination liquid flow 68. It is because specific gravity is large at low temperature compared with a decontamination liquid.

  In the decontamination apparatus 1 of the facility in the nuclear power plant, no heat insulating material or the like is provided on the surface of the PLR horizontal pipe 23. For this reason, the decontamination liquid constituting the decontamination liquid flow 70 in the PLR horizontal pipe 23 is transferred in the PLR horizontal pipe 23 as compared with the case where a heat insulating material or the like is provided on the surface of the PLR horizontal pipe 23. More heat is dissipated and the temperature drops. In other words, the decontamination liquid flow 70 has a large negative temperature gradient with respect to the movement direction of the decontamination liquid in the PLR horizontal pipe 23.

  It is preferable that the decontamination liquid stream 70 has a large negative temperature gradient in the PLR horizontal pipe 23 because the flow rate of the circulating flow composed of the decontamination liquid streams 68 and 70 is increased.

  Thus, in the PLR vertical pipe 22 and the PLR horizontal pipe 23, a decontamination liquid flow 68 using a fresh and relatively high temperature decontamination liquid and a decontamination liquid flow using a relatively low temperature decontamination liquid after decontamination. 70 in a state where the temperature difference is large.

  In the PLR horizontal pipe 23, the temperature is adjusted so that the average temperature of the decontamination liquid in the PLR horizontal pipe 23 decreases as the temperature of the PLR horizontal pipe 23 increases from the upper end 225 of the PLR vertical pipe 22. Here, the average temperature of the decontamination liquid in the PLR horizontal pipe 23 is the temperature of the decontamination liquid constituting the decontamination liquid flow 68 at a certain point in the PLR horizontal pipe 23 and the decontamination liquid constituting the decontamination liquid flow 70. Means the average value with the temperature.

  A part of the decontamination liquid flow 68 in the PLR horizontal pipe 23 branches to the PLR riser pipe 24 to form a decontamination liquid flow 69 in the PLR riser pipe 24.

(Operation in PLR riser pipe)
The decontamination liquid flow 69 in the PLR riser pipe 24 will be described with reference to FIG. FIG. 3 is an enlarged view of the PLR collective piping section shown in FIG.

  As shown in FIG. 3, the decontamination liquid flow 69 in the PLR riser pipe 24 includes a decontamination liquid flow 71 that forms an upward flow in the PLR riser pipe 24, and the decontamination liquid flow 71 is the liquid level of the decontamination liquid. And a decontamination liquid flow 72 that reverses in the vicinity of 73 and forms a downward flow in the PLR riser tube 24. The decontamination liquid flow 71 and the decontamination liquid flow 72 are an upward flow and a downward flow generated by convection of the decontamination liquid flow 69, respectively.

  The reason why the decontamination liquid flow 71 forms an upward flow in the PLR riser pipe 24 and the decontamination liquid flow 72 forms a downward flow in the PLR riser pipe 24 is because the decontamination liquid constituting the decontamination liquid flow 71 This is because the specific gravity is small at a high temperature as compared with the decontamination liquid constituting the decontamination liquid flow 72.

  The decontamination liquid flow 71 is folded at the tip of the PLR riser tube 24 to form a decontamination liquid flow 72 shown in FIG. The decontamination liquid stream 72 joins the decontamination liquid stream 68 or 70 in the PLR horizontal pipe 23.

  In the decontamination apparatus 1 of the facility in the nuclear power plant, no heat insulating material or the like is provided on the surface of the PLR riser pipe 24. Further, the outer surface of the PLR riser tube 24 is locally cooled by the blower 51. For this reason, as the decontamination liquid constituting the decontamination liquid flows 71 and 72 moves upward or downward in the PLR riser tube 24, a large amount of heat is dissipated and the temperature rapidly decreases. For this reason, the decontamination liquid flows 71 and 72 in the PLR riser pipe 24 have a large negative temperature gradient with respect to the moving direction of the decontamination liquid.

  It is preferable that the decontamination liquid streams 71 and 72 have a large negative temperature gradient in the PLR riser tube 24 because the flow rates of the decontamination liquid streams 71 and 72 will increase. This is because the decontamination liquids 71 and 72 each have a negative temperature gradient in the PLR riser tube 24, and the decontamination liquid that constitutes the decontamination liquid stream 71 and the decontamination liquid that constitutes the decontamination liquid stream 72. This is because the flow rate of the decontamination liquids 71 and 72 is increased.

  In addition, when the temperature of a decontamination liquid will be less than 80 degreeC, there exists a possibility that a decontamination capability may fall. For this reason, in this invention, it is preferable that the temperature in the liquid level 73 of the PLR riser pipe | tube 24 of the high temperature decontamination liquid which comprises the decontamination liquid flow 71 is 80 degreeC or more.

  In the PLR riser pipe 24, the temperature is adjusted so that the average temperature of the decontamination liquid in the PLR riser pipe 24 decreases with increasing distance from the upper end 225 of the PLR vertical pipe 22. Here, the average temperature of the decontamination liquid in the PLR riser pipe 24 is the temperature of the decontamination liquid constituting the decontamination liquid flow 71 at a certain point in the PLR riser pipe 24 and the temperature of the decontamination liquid constituting the decontamination liquid flow 72. Means the average value with temperature.

  The decontamination liquid stream 72 joins the decontamination liquid stream 68 or 70 in the PLR horizontal pipe 23. When the decontamination liquid stream 72 joins the decontamination liquid stream 68 or 70, the temperature of the decontamination liquid stream 68 or 70 decreases, so that the decontamination liquid stream 68 and 70 are compared with the case where the decontamination liquid stream 72 does not join. The flow rate of the circulating flow composed of 70 is further increased.

  According to the decontamination apparatus 1 of the facility in the nuclear power plant, the heat insulating material or the like is not provided in the PLR horizontal pipe 23 and the PLR riser pipe 24 and heat dissipation is easy, and the outer surface of the PLR riser pipe 24 is locally cooled. Since the blower 51 is provided, the average temperature of the decontamination liquid in the PLR horizontal pipe 23 and the PLR riser pipe 24 decreases as the distance from the upper end 225 of the PLR vertical pipe 22 increases. For this reason, according to the decontamination apparatus 1 of the facility in the nuclear power plant, the flow rate of the decontamination liquid in the PLR collecting pipe part 25 is high, and the decontamination efficiency is high.

  Moreover, if the degree to which the average temperature of the decontamination liquid in the PLR horizontal pipe 23 and the PLR riser pipe 24 decreases as the distance from the upper end 225 of the PLR vertical pipe 22 increases, the flow rate of the decontamination liquid becomes faster, Decontamination efficiency is higher.

  In addition, in the decontamination apparatus 1 of the facility in the nuclear power plant, the height of the liquid surface 73 of the decontamination liquid in the PLR riser pipe 24 is made substantially constant, but the decontamination liquid may enter the reactor pressure vessel. In that case, the height of the liquid surface 73 may not be made substantially constant. In addition, when a means for blocking the flow path such as a cap and a valve is provided in the upper part of the PLR riser pipe 24, the removal is performed without adjusting the height of the liquid level 73 of the decontamination liquid in the PLR riser pipe 24. The dyeing solution may be filled up to the installation site such as a cap and a valve.

[Second Embodiment]
The nuclear power plant equipment decontamination apparatus 1A, which is the second embodiment of the nuclear power plant equipment decontamination apparatus of the present invention, is compared with the nuclear power plant equipment decontamination equipment 1 shown in FIG. 1 as the first embodiment. Thus, the PLR collective piping part 25A is used in place of the PLR collective pipe part 25, and the other points are the same. For this reason, the decontamination apparatus 1A for facilities in a nuclear power plant is shown in FIG. The description of the configuration and operation is omitted or simplified.

  FIG. 4 is an enlarged view of the PLR collective piping portion 25A constituting the decontamination apparatus 1A for the facility in the nuclear power plant. The PLR collective piping portion 25A is different from the PLR collective piping portion 25 shown in FIG. 2 in that a blower 51A is provided instead of the blower 51, and the other points are the same. For this reason, the PLR collective piping section 25A shown in FIG. 4 attaches the same reference numerals to the same configuration as the PLR collective piping section 25 shown in FIG. 2, and omits or simplifies the description of the configuration and action. 4 has the PLR riser pipe 24 arranged in the same manner as the PLR collective pipe section 25 shown in FIG. 2, the description of the PLR riser pipe 24 is omitted in FIG. 4.

  The PLR collective piping section 25A is provided with a blower 51A as temperature adjusting means for locally cooling the outer surface of the PLR horizontal pipe 23 by blowing air. Four blowers 51 </ b> A are provided to face the PLR horizontal pipe 23. In the present invention, the number of fans 51A installed is not particularly limited, and can be increased or decreased as appropriate.

  Next, the operation at the time of decontamination work of the decontamination apparatus 1A for the facility in the nuclear power plant will be described.

  The operation of the decontamination work of the nuclear power plant facility decontamination apparatus 1A is compared with the operation of the decontamination work 1 of the nuclear power plant facility decontamination work 1 compared to the blower of the decontamination apparatus 1 of the nuclear power plant equipment. 51 is locally cooled on the outer surface of the PLR riser pipe 24, whereas the blower 51A of the decontamination apparatus 1A of the facility in the nuclear power plant locally cools the outer surface of the PLR horizontal pipe 23 is different. Other actions are the same. For this reason, below, the effect | action different with the decontamination apparatus 1A of the facility in a nuclear power station and the decontamination apparatus 1 of the facility in a nuclear power station is demonstrated.

  In the decontamination apparatus 1A for the nuclear power plant equipment, no heat insulating material or the like is provided on the surface of the PLR riser pipe 24, but the outer surface of the PLR riser pipe 24 is cooled by a blower like the decontamination equipment 1 for the nuclear power plant equipment. It is never done. For this reason, the temperature of the decontamination liquid constituting the decontamination liquid flows 71 and 72 in the PLR riser pipe 24 is slowly lowered in the PLR riser pipe 24. For this reason, the decontamination liquid flows 71 and 72 in the PLR riser pipe 24 have a relatively small negative temperature gradient with respect to the moving direction of the decontamination liquid.

  On the other hand, in the decontamination apparatus 1A for the facility in the nuclear power plant, the outer surface of the PLR horizontal pipe 23 is locally cooled by the blower 51A. For this reason, as the decontamination liquid constituting the decontamination liquid flows 68 and 70 moves in the PLR horizontal pipe 23, a large amount of heat is dissipated and the temperature rapidly decreases. For this reason, the decontamination liquid flows 68 and 70 in the PLR horizontal pipe 23 have a large negative temperature gradient with respect to the moving direction of the decontamination liquid.

  Since other operations at the time of decontamination work are the same in the decontamination apparatus 1A for the facilities in the nuclear power plant and the decontamination apparatus 1 in the facilities in the nuclear power plant, description of the operations is omitted.

  According to the decontamination apparatus 1A for the facility in the nuclear power plant, the PLR horizontal pipe 23 and the PLR riser pipe 24 are not provided with a heat insulating material or the like, and thus heat radiation is easy, and the outer surface of the PLR horizontal pipe 23 is locally cooled. Since the blower 51 </ b> A is provided, the average temperature of the decontamination liquid in the PLR horizontal pipe 23 and the PLR riser pipe 24 decreases as the distance from the upper end 225 of the PLR vertical pipe 22 increases. For this reason, according to the decontamination apparatus 1A for the facility in the nuclear power plant, the flow rate of the decontamination liquid in the PLR collective piping section 25A is high, and the decontamination efficiency is high.

[Third Embodiment]
A nuclear power plant facility decontamination apparatus 1B, which is a third embodiment of the nuclear power plant facility decontamination apparatus of the present invention, is compared with the nuclear power plant facility decontamination apparatus 1A shown in FIG. 1 as the second embodiment. The difference is that the PLR collective piping portion 25B is used instead of the PLR collective piping portion 25A, and the other points are the same. For this reason, the decontamination apparatus 1B for the facility in the nuclear power plant is shown in FIG. 1 like the decontamination device 1A for the facility in the nuclear power plant, and the same reference numerals are given to the same components as the decontamination device 1A in the facility in the nuclear power station. The description of the configuration and operation is omitted or simplified.

  FIG. 5 is an enlarged view of the PLR collective piping section 25B constituting the decontamination apparatus 1B for the facility in the nuclear power plant. The PLR collective piping portion 25B is different from the PLR collective piping portion 25A shown in FIG. 3 in that a heater 52 is provided instead of the blower 51, and the other points are the same. For this reason, the PLR collective piping part 25B shown in FIG. 5 attaches | subjects the same code | symbol to the same structure as the PLR collective pipe part 25A shown in FIG. 3, and abbreviate | omits or simplifies description of a structure and an effect | action.

  The PLR collective piping section 25B is provided with a heater 52 as temperature adjusting means for locally heating the outer surface of the PLR horizontal pipe 23. Two heaters 52 are provided on the outer surface of the PLR horizontal tube 23, near the upper end 225 of the PLR vertical tube 22 and on the upper side of the PLR horizontal tube 23. The heater 52 is provided at such a position so that the decontamination liquid in the decontamination liquid flow 68 that forms an upward flow in the PLR horizontal pipe 23 becomes the highest temperature in the vicinity of the upper end 225 of the PLR vertical pipe 22. This is for heating. As the heater 52, a known one can be used. In the present invention, the number of heaters 52 installed is not particularly limited and can be increased or decreased as appropriate.

  Next, the effect | action at the time of the decontamination operation | work of the decontamination apparatus 1B of the facility in a nuclear power plant is demonstrated.

  The operation of the decontamination work of the nuclear power plant equipment decontamination device 1B is compared to the operation of the decontamination work of the nuclear power plant equipment decontamination work 1A compared to the operation of the decontamination equipment 1A of the nuclear power plant equipment. 51 differs locally in that the outer surface of the PLR horizontal pipe 23 is cooled, whereas the heater 52 of the decontamination apparatus 1B of the facility in the nuclear power plant locally heats the outer surface of the PLR horizontal pipe 23. Other actions are the same. For this reason, the operation different between the decontamination apparatus 1B for the facility in the nuclear power plant and the decontamination apparatus 1A for the facility in the nuclear power plant will be described below.

  In the decontamination apparatus 1B of the facility in the nuclear power plant, the heater 52 locally heats the outer surface of the PLR horizontal tube 23 near the upper end 225 of the PLR vertical tube 22 and on the upper side of the PLR horizontal tube 23. .

  For this reason, the decontamination liquid constituting the decontamination liquid flow 68 becomes the highest temperature near the upper end 225 of the PLR vertical pipe 22 in the PLR horizontal pipe 23, and the average of the decontamination liquid in the PLR horizontal pipe 23 Since the temperature difference increases, the flow rate of the decontamination liquid flow 68 in the PLR horizontal pipe 23 increases. In the PLR horizontal pipe 23, the flow rate of the decontamination liquid flow 70 increases as the flow rate of the decontamination liquid flow 68 increases.

  Further, since a part of the decontamination liquid flow 68 made of the high temperature decontamination liquid is introduced, the decontamination liquid in the decontamination liquid stream 71 in the PLR riser pipe 24 becomes higher in temperature, so that the PLR riser pipe 24 The flow rates of the decontamination liquid flows 71 and 72 are increased.

  Since the other operations at the time of decontamination work are the same in the decontamination apparatus 1B for facilities in the nuclear power plant and the decontamination apparatus 1A for facilities in the nuclear power plant, description of the operations is omitted.

  According to the decontamination apparatus 1B of the facility in the nuclear power plant, the PLR horizontal pipe 23 and the PLR riser pipe 24 are not provided with a heat insulating material and the like, and heat dissipation is easy, and the outer surface of the PLR horizontal pipe 23 is locally heated. Since the heater 52 is provided, the average temperature of the decontamination liquid in the PLR horizontal pipe 23 and the PLR riser pipe 24 decreases with increasing distance from the upper end 225 of the PLR vertical pipe 22, and the decontamination liquid in the PLR horizontal pipe 23. Streams 68, 70 and flow rates of decontamination liquid streams 71, 72 in PLR riser tube 24 are increased.

  For this reason, according to the decontamination apparatus 1B of the facility in the nuclear power plant, the flow rate of the decontamination liquid in the PLR collecting pipe portion 25B is high, and the decontamination efficiency is high.

  In the decontamination apparatus 1B for the facility in the nuclear power plant, a heater 52 for locally heating the outer surface of the PLR horizontal pipe 23 is provided. However, in the decontamination device for the facility in the nuclear power plant according to the present invention, the PLR riser tube A heater for locally heating the outer surface of 24 may be provided. When a heater for locally heating the outer surface of the PLR riser pipe 24 is provided, if the heater is provided on a portion of the outer surface of the PLR riser pipe 24 close to the connection portion with the PLR horizontal pipe 23, the heater inside the PLR riser pipe 24 is removed. The flow velocity of the dye liquor flows 71 and 72 is increased.

  In the decontamination apparatus 1B for the nuclear power plant facilities shown as the first embodiment, the decontamination apparatus 1B for the nuclear power plant facilities shown in the third embodiment, respectively. In FIG. 1, a blower 51 for cooling the PLR riser pipe 24 is provided. In the decontamination apparatus 1A for the facility in the nuclear power plant, a blower 51A for cooling the PLR horizontal pipe 23 is provided, and in the decontamination device 1B for the facility in the nuclear power plant, the PLR horizontal pipe. A heater 52 for heating 23 is provided.

  However, in the decontamination apparatus for facilities in a nuclear power plant according to the present invention, the blower 51 for cooling the PLR riser pipe 24, the blower 51A for cooling the PLR horizontal pipe 23, the heater 52 for heating the PLR horizontal pipe 23, and the PLR riser pipe It is good also as a structure which combined 2 or more types of the heater which heats 24 outer surfaces locally.

[Fourth Embodiment]
FIG. 6 is a diagram showing a fourth embodiment of the decontamination apparatus for facilities in a nuclear power plant according to the present invention.

  The decontamination apparatus 1C for the facility in the nuclear power plant shown in FIG. 6 has a decontamination apparatus 30C instead of the decontamination device 30 as compared with the decontamination device 1 in the facility in the nuclear power station shown as the first embodiment in FIG. It differs in the points used, and the other points are the same.

  For this reason, in FIG. 6, the same code | symbol is attached | subjected to the same structure of the decontamination apparatus 1C of the facility in a nuclear power station, and the decontamination apparatus 1 of the facility in a nuclear power station, and description of a structure and an effect | action is abbreviate | omitted or simplified.

  The decontamination apparatus 30C constituting the decontamination apparatus 1C for the facility in the nuclear power plant is decontamination piping relative to the decontamination apparatus 30 constituting the decontamination apparatus 1 for the facility in the nuclear power station shown as the first embodiment in FIG. The first decontamination bypass pipe 41 branched from the decontamination pipe portion 312 of the 31 and connected to the side wall of the PLR vertical pipe 22 of the reactor recirculation pipe 21, and the decontamination in the first decontamination bypass pipe 41 And a bypass heater 42 for heating the dye liquor.

  The first decontamination bypass pipe 41 is a pipe that supplies a part of the decontamination liquid in the decontamination pipe 31 to the side wall of the PLR vertical pipe 22. The remainder of the decontamination liquid in the decontamination pipe 31 is supplied to the reactor recirculation system pipe 21 from a decontamination liquid supply port 47 a provided in the branch pipe 221 communicating with the PLR vertical pipe 22.

  The bypass heater 42 heats the decontamination liquid in the first decontamination bypass pipe 41 to 90 ° C. or higher.

  Next, the action at the time of decontamination work of the decontamination apparatus 1C for the facility in the nuclear power plant will be described with reference to the drawings.

  The decontamination operation of the decontamination apparatus 1C of the facility in the nuclear power plant is equivalent to the decontamination operation of the decontamination device 1 in the facility of the nuclear power station, instead of the decontamination device 30. That is, the operation based on the point that the decontamination apparatus further includes the first decontamination bypass pipe 41 and the bypass heater 42 is different, and the other points are the same. For this reason, below, the effect | action different with the decontamination apparatus C of the facility in a nuclear power plant and the decontamination apparatus 1 of the facility in a nuclear power plant is demonstrated.

  In the decontamination work of the decontamination apparatus 1C for the facility in the nuclear power plant, first, in the same way as the decontamination work for the decontamination device 1 in the facility of the nuclear power station, the PLR vertical pipe 22, the PLR horizontal pipe 23, and the PLR riser pipe 24 are entered. The decontamination liquid is introduced, and the height of the liquid surface 73 of the decontamination liquid in the PLR riser pipe 24 is made substantially constant.

(Operation in PLR vertical pipe and PLR horizontal pipe)
With reference to FIG. 7 and FIG. 8, the effect | action of the decontamination liquid flow which goes to the edge part in a PLR horizontal pipe from a PLR vertical pipe is demonstrated.

  FIG. 7 is an enlarged view of the PLR collective piping section 25C constituting the decontamination apparatus 1C for the facility in the nuclear power plant, and the decontamination in the first decontamination process in which the valve 46 of the first decontamination bypass pipe 41 is closed. The dye liquor flow is shown. FIG. 8 is an enlarged view of the PLR collective piping section 25C constituting the decontamination apparatus 1C for the facility in the nuclear power plant, and the decontamination in the second decontamination process in which the valve 46 of the first decontamination bypass pipe 41 is opened. The dye liquor flow is shown.

<First decontamination process>
In the first decontamination step, the decontamination liquid is supplied from the decontamination pipe 31 to the PLR vertical pipe 22 of the reactor recirculation system pipe 21 only through the decontamination liquid supply port 47.

  Specifically, as shown in FIG. 7, the high temperature decontamination liquid transferred from the branch pipe 221 communicating with the decontamination liquid supply port 47 into the PLR vertical pipe 22 of the reactor recirculation pipe 21 is removed. A dye liquor stream 68a is formed. The decontamination liquid flow 68 a is formed so as to flow upward in the PLR vertical pipe 22 and toward the end in the PLR horizontal pipe 23.

  The decontamination liquid flow 68a is always formed regardless of whether the valve 46 of the first decontamination bypass pipe 41 is open or closed. However, when the valve 46 is opened, a part of the decontamination liquid in the decontamination pipe 31 flows to the first decontamination bypass pipe 41 side, so that the flow rate of the decontamination liquid flow 68a usually decreases.

<Second decontamination process>
The second decontamination process is performed after the first decontamination process. The second decontamination process is usually the first decontamination process, such as the first decontamination process, the second decontamination process, the first decontamination process, the second decontamination process,. Alternately.

  Switching between the first decontamination process and the second decontamination process is performed by opening and closing the valve 46 of the first decontamination bypass pipe 41. Specifically, the first decontamination process is a decontamination process in a state where the valve 46 is closed, and the second decontamination process is a decontamination process in a state where the valve 46 is opened.

  Normally, the valve 46 of the first decontamination bypass pipe 41 is opened and closed intermittently at regular intervals. That is, in the normal decontamination work, a method is employed in which the valve 46 is opened for a short time during the long-time first decontamination process to perform the short decontamination process.

  In the second decontamination process, the decontamination liquid is supplied from the decontamination pipe 31 to the PLR vertical pipe 22 of the reactor recirculation system pipe 21 through the decontamination liquid supply port 47 as in the first decontamination process. In addition, a decontamination liquid having a temperature higher than that of the decontamination liquid supplied through the decontamination liquid supply port 47 passes from the first decontamination bypass pipe 41 of the decontamination apparatus 30 to the reactor recirculation system pipe 21. The PLR vertical pipe 22 is supplied.

  Specifically, when the valve 46 of the first decontamination bypass pipe 41 is opened, a part of the high-temperature decontamination liquid in the decontamination pipe portion 312 of the decontamination pipe 31 is changed to the first decontamination bypass pipe 41. To be supplied. The high-temperature decontamination liquid supplied to the first decontamination bypass pipe 41 is heated to a higher temperature by the bypass heater 42, and then, as shown in FIG. It is transferred into the tube 22 to form a decontamination liquid stream 68b. The decontamination liquid flow 68 b is formed so as to flow upward in the PLR vertical pipe 22.

  The decontamination liquid streams 68a and 68b merge in the PLR vertical pipe 22 to form a decontamination liquid stream 68c. The temperature of the decontamination liquid in the decontamination liquid stream 68c in the second decontamination process is higher than the temperature of the decontamination liquid in the decontamination liquid stream 68a in the first decontamination process.

  For this reason, the difference in the temperature of the decontamination liquid between the decontamination liquid streams 68c and 70 in the second decontamination process is equal to the temperature of the decontamination liquid between the decontamination liquid streams 68a and 70 in the first decontamination process. The difference becomes larger, and the buoyancy effect of the decontamination liquid is increased in the second decontamination process than in the first decontamination process, and the flow rate of the circulation flow between the decontamination liquid flows 68c and 70 is also increased. As a result, the decontamination device 1C for the facility in the nuclear power plant has higher decontamination efficiency than the decontamination device 1 for the facility in the nuclear power plant.

  In the second decontamination process, when the buoyancy effect of the decontamination liquid is sufficiently increased and the continuation of the second decontamination process becomes unnecessary, the valve 46 of the first decontamination bypass pipe 41 is appropriately closed. Terminate.

  Since other operations at the time of decontamination work are the same in the decontamination apparatus 1C for facilities in the nuclear power plant and the decontamination apparatus 1 for facilities in the nuclear power plant, description of the operations is omitted.

  According to the decontamination apparatus 1C for the facility in the nuclear power plant, the decontamination liquid flows 68c and 70 are formed in addition to the effects at the time of the decontamination work similar to the decontamination device 1 for the facility in the nuclear power plant shown as the first embodiment. Since the flow rate of the circulating flow is high, the decontamination efficiency is higher than that of the decontamination apparatus 1 of the facility in the nuclear power plant.

[Fifth Embodiment]
FIG. 9 is a diagram showing a fifth embodiment of the decontamination apparatus for facilities in a nuclear power plant according to the present invention.

  A decontamination apparatus 1D for facilities in a nuclear power plant shown in FIG. 9 is different from the decontamination apparatus 1 in facilities in a nuclear power station shown in FIG. It differs in the points used, and the other points are the same.

  For this reason, in FIG. 9, the same code | symbol is attached | subjected to the same structure of the decontamination apparatus 1D of the facility in a nuclear power station, and the decontamination apparatus 1 of the facility in a nuclear power station, and description of a structure and an effect | action is abbreviate | omitted or simplified.

  The decontamination apparatus 30D constituting the decontamination apparatus 1D for the facility in the nuclear power plant is different from the decontamination apparatus 30 constituting the decontamination apparatus 1 for the facility in the nuclear power station shown in FIG. 1 as the first embodiment. An air bubble generating device 55 is further provided for including air bubbles in the decontamination liquid in the PLR vertical pipe 22 of the circulation system pipe 21.

  The bubble generating device 55 is a device that generates bubbles having a diameter of 200 μm to 500 μm in the decontamination liquid. As the bubble generating device 55, a known bubble generating device can be used.

  Next, the action at the time of decontamination work of the decontamination apparatus 1D of the facility in the nuclear power plant will be described with reference to the drawings.

  The decontamination operation of the decontamination device 1D of the facility in the nuclear power plant is performed in place of the decontamination device 30 in comparison with the operation during the decontamination operation of the decontamination device 1 of the facility in the nuclear power plant. That is, the operation based on the point that the decontamination apparatus further includes the bubble generation device 55 is different, and the other points are the same. For this reason, below, the effect | action different with the decontamination apparatus D of the facility in a nuclear power station and the decontamination apparatus 1 of the facility in a nuclear power station is demonstrated.

  In the decontamination work of the decontamination apparatus 1D of the facility in the nuclear power plant, first, in the same way as the decontamination work of the decontamination device 1 in the facility of the nuclear power station, the PLR vertical pipe 22, the PLR horizontal pipe 23, and the PLR riser pipe 24 are entered. The decontamination liquid is introduced, and the height of the liquid surface 73 of the decontamination liquid in the PLR riser pipe 24 is made substantially constant.

(Operation in PLR vertical pipe and PLR horizontal pipe)
With reference to FIG. 10, the operation of the decontamination liquid flow from the PLR vertical pipe toward the end in the PLR horizontal pipe will be described.

  FIG. 10 is an enlarged view of the PLR collective piping section 25D constituting the decontamination apparatus 1D for the facility in the nuclear power plant. In FIG. 10, the decontamination liquid flow 70 shown in FIG. 2, that is, the decontamination liquid flow toward the PLR vertical pipe 22 by being folded back at the tip of the PLR horizontal pipe 23 is omitted.

  In a state where the bubble generating device 55 is not operated, the flow of the decontamination liquid in the PLR collective piping section 25D is the same as the decontamination liquid flows 68 and 70 of the PLR collective piping section 25 shown in FIG. The decontamination liquid flow 68 is a flow of the decontamination liquid formed so as to flow upward in the PLR vertical pipe 22 and toward the end portion in the PLR horizontal pipe 23. The decontamination liquid flow 70 is formed so as to flow downward in the PLR vertical pipe 22 and flow in the PLR horizontal pipe 23 from the end of the PLR horizontal pipe 23 toward the upper end 225 of the PLR vertical pipe 22. It is the flow of.

  However, when the bubble generating device 55 is operated, as shown in FIG. 10, the bubbles 56 are supplied from the bubble generating device 55 into the decontamination liquid in the PLR vertical pipe 22 of the PLR collective piping section 25C. Since the bubbles 56 increase the buoyancy of the decontamination liquid flow, the decontamination liquid flow 68d configured from the decontamination liquid including the bubbles 56 is configured from the decontamination liquid illustrated in FIG. Compared with the decontamination liquid flow 68, the flow velocity becomes faster.

  The decontamination liquid containing the bubbles 56 is supplied from the PLR horizontal pipe 23 into the PLR riser pipe 24 to form a decontamination liquid flow 69d in the PLR riser pipe 24. The decontamination liquid flow 69d composed of the decontamination liquid containing the bubbles 56 also has a higher flow rate than the decontamination liquid flow 69 composed of the decontamination liquid shown in FIG. .

  In the case where the bubble generating device 55 is not used unlike the decontamination device 1D of the facility in the nuclear power plant, the decontamination liquid flow 68 composed of the decontamination solution not including the bubbles 56 has an end portion in the PLR horizontal pipe 23, That is, the decontamination solution is consumed as it goes to the far side in the traveling direction, and the decontamination effect may decrease in the middle of the PLR horizontal pipe 23. The decontamination liquid flow 68 composed of the decontamination liquid that does not include the bubbles 56 includes a dynamic pressure component when discharged from the PLR vertical pipe 22 to the PLR horizontal pipe 23, and a specific gravity difference based on the temperature difference of the decontamination liquid. This is because a dynamic pressure component and a specific gravity difference are reduced in the middle of the PLR horizontal pipe 23 because the flow is formed by driving.

  On the other hand, in the decontamination apparatus 1D of the facility in the nuclear power plant, the decontamination liquid containing the bubbles 56 is carried by the bubbles 56 into the end portion in the PLR horizontal tube 23 and the PLR riser tube 24 with a strong driving force. Further, the decontamination liquid containing bubbles 56 is decontaminated because the bubbles 56 dissolve in the decontamination liquid and the volume of the decontamination liquid decreases when the concentration of the decontamination agent decreases in the middle of the PLR horizontal pipe 23. The replenishment of the liquid serves as a driving force for the concentration of the decontaminating agent and the flow of the decontaminating liquid, and is effectively carried into the end of the PLR horizontal pipe 23 and the PLR riser pipe 24.

  Since other operations at the time of decontamination work are the same in the decontamination apparatus 1D for facilities in the nuclear power plant and the decontamination apparatus 1 in facilities in the nuclear power plant, description of the operations is omitted.

  According to the decontamination apparatus 1D for the facility in the nuclear power plant, in addition to the same effect as the decontamination work similar to the decontamination device 1 for the facility in the nuclear power plant shown as the first embodiment, the decontamination liquid has a stronger driving force due to the bubbles 56. Therefore, the decontamination efficiency is higher than that of the decontamination apparatus 1 of the facility in the nuclear power plant.

[Sixth Embodiment]
FIG. 11 is a diagram showing a sixth embodiment of the decontamination apparatus for facilities in a nuclear power plant according to the present invention. FIG. 12 is an enlarged view of the PLR collective piping section 25E constituting the decontamination apparatus 1E for the facility in the nuclear power plant shown in FIG.

  A decontamination apparatus 1E for facilities in a nuclear power plant shown in FIG. 11 is different from the decontamination apparatus 1 for facilities in a nuclear power plant shown in FIG. It differs in the points used, and the other points are the same.

  For this reason, in FIG. 11, the same code | symbol is attached | subjected to the same structure of the decontamination apparatus 1E of the nuclear power plant facilities, and the decontamination apparatus 1 of the nuclear power plant facilities, and description of a structure and an effect | action is abbreviate | omitted or simplified.

  The decontamination apparatus 30E constituting the decontamination apparatus 1E for the facility in the nuclear power plant is decontaminated from the decontamination apparatus 30 constituting the decontamination apparatus 1 for the facility in the nuclear power station shown as the first embodiment in FIG. 31 is branched from the injection pipe 36 connecting the decontamination liquid injection part 32 for injecting the decontamination liquid to the decontamination pipe 31 and connected to the side wall of the PLR vertical pipe 22 of the reactor recirculation system pipe 21. The second decontamination bypass pipe 43 and the second decontamination bypass pipe 43 communicated with the second decontamination bypass pipe 43 and a connecting portion 44 between the second decontamination bypass pipe 43 and the PLR vertical pipe 22 project into the PLR vertical pipe 22 and the leading end is PLR. And a decontamination liquid injection tube 45 bent upward in the vertical tube 22.

  The second decontamination bypass pipe 43 is a pipe that supplies a part of the fresh decontamination liquid in the injection pipe 36 connected to the decontamination pipe 31 to the side wall of the PLR vertical pipe 22. The remainder of the fresh decontamination liquid in the injection pipe 36 is injected into the decontamination pipe 31, and from the decontamination liquid supply port 47 a provided in the branch pipe 221 communicating with the PLR vertical pipe 22, the reactor recirculation system pipe 21. To be supplied.

  The decontamination liquid injection pipe 45 has a shape that protrudes entirely into the PLR vertical pipe 22 and has a tip bent upward in the PLR vertical pipe 22. The decontamination liquid in the second decontamination bypass pipe 43 is used as the decontamination liquid injection pipe 45. In the PLR vertical pipe 22, the discharge is performed upward.

  Next, the action at the time of decontamination work of the decontamination apparatus 1E for the facility in the nuclear power plant will be described with reference to the drawings.

  The decontamination operation of the decontamination device 1E of the facility in the nuclear power plant is performed in place of the decontamination device 30 instead of the decontamination operation of the decontamination device 1 of the facility in the nuclear power plant. That is, the operation based on the point that the decontamination apparatus further includes the second decontamination bypass pipe 43 and the decontamination liquid injection pipe 45 is different, and the other points are the same. For this reason, below, the effect | action different with the decontamination apparatus E of the installation in a nuclear power station and the decontamination apparatus 1 of the installation in a nuclear power station is demonstrated.

  In the decontamination work of the decontamination apparatus 1E of the facility in the nuclear power plant, first, in the same way as the decontamination work of the decontamination device 1 in the facility of the nuclear power station, the PLR vertical pipe 22, the PLR horizontal pipe 23, and the PLR riser pipe 24 are entered. The decontamination liquid is introduced, and the height of the liquid surface 73 of the decontamination liquid in the PLR riser pipe 24 is made substantially constant.

(Operation by the second decontamination bypass pipe and decontamination liquid injection pipe)
Next, when the decontamination liquid is injected from the decontamination liquid injection part 32, a part of the injected decontamination liquid is supplied to the decontamination pipe 31, and the remaining part of the injected decontamination liquid is connected to the decontamination pipe 31. It is supplied from the injection pipe 36 to the second decontamination bypass pipe 43.

(Operation in PLR vertical pipe and PLR horizontal pipe)
With reference to FIG. 12, the operation of the decontamination liquid flow from the PLR vertical pipe toward the end in the PLR horizontal pipe will be described. In FIG. 12, the decontamination liquid flow in the PLR riser pipe 24, that is, the decontamination liquid flow 69 shown in FIG.

  The high temperature decontamination liquid transferred from the branch pipe 221 into the PLR vertical pipe 22 forms a decontamination liquid flow 68a shown in FIG. The decontamination liquid flow 68a is a flow of the decontamination liquid formed so as to flow upward in the PLR vertical pipe 22 and toward the end in the PLR horizontal pipe 23. Most of the high temperature decontamination liquid transferred from the branch pipe 221 into the PLR vertical pipe 22 forms a decontamination liquid flow 68a, but a part of the high temperature decontamination liquid transferred from the branch pipe 221 is A decontamination liquid flow (not shown) that flows downward from the branch pipe 221 in the PLR vertical pipe 22 is formed.

  On the other hand, the high-temperature decontamination liquid transferred from the decontamination liquid injection pipe 45 into the PLR vertical pipe 22 through the second decontamination bypass pipe 43 and the connection portion 44 forms a decontamination liquid flow 68e shown in FIG. To do. Since the discharge port of the decontamination liquid injection pipe 45 is formed upward in the PLR vertical pipe 22, the decontamination liquid flow 68 e is surely formed upward in the PLR vertical pipe 22. That is, most of the hot decontamination liquid transferred from the decontamination liquid injection pipe 45 into the PLR vertical pipe 22 forms an upward decontamination liquid flow 68 e in the PLR vertical pipe 22.

  The decontamination liquid streams 68a and 68e merge to form a decontamination liquid stream 68f. Since the decontamination liquid flow 68f is a combination of the decontamination liquid flows 68a and 68e formed upward in the PLR vertical pipe 22, the PLR vertical pipe 22 is compared with the case of only the decontamination liquid flow 68a. The flow of the decontamination liquid in the interior is strongly upward, and the flow rate of the decontamination liquid flow is increased.

  For this reason, in the decontamination apparatus 1E of the facility in the nuclear power plant, the flow rate of the circulating flow formed by the decontamination liquid flows 68f and 70 having a high flow rate is increased, so that the decontamination device 1 in the facility of the nuclear power plant is compared. Decontamination efficiency increases.

  Since other operations at the time of decontamination work are the same in the decontamination apparatus 1E for facilities in the nuclear power plant and the decontamination apparatus 1 for facilities in the nuclear power plant, description of the operations is omitted.

  According to the decontamination apparatus 1E for the facility in the nuclear power plant, in addition to the effect at the time of the decontamination work similar to the decontamination device 1 for the facility in the nuclear power plant shown as the first embodiment, the decontamination liquid flows 68f and 70 are formed. Since the flow rate of the circulating flow is high, the decontamination efficiency is higher than that of the decontamination apparatus 1 of the facility in the nuclear power plant.

1, 1A, 1B, 1C, 1D, 1E Decontamination equipment for nuclear power plant facilities 21 Recirculation reactor piping (PLR piping)
22 PLR vertical pipe 221 Branch pipe 223 Branch part 225 Upper end 23 of PLR vertical pipe PLR horizontal pipe 24 PLR riser pipe 25, 25A, 25B, 25C, 25D, 25E PLR collective pipe part 27 Recirculation pump inlet side pipe 29 Recirculation Pump 30, 30C, 30D, 30E Decontamination device 31 Decontamination piping 310 Decontamination piping branch points 311, 312, 313 Decontamination piping portion 32 Decontamination liquid injection part 33 Decontamination heater 34 Cationic resin tower 35 Reduction device 36 Injection piping 39 Decontamination pump 41 1st decontamination bypass pipe 42 Bypass heater 43 2nd decontamination bypass pipe 44 Connection part of 2nd decontamination bypass pipe and PLR vertical pipe 45 Decontamination liquid injection pipe 46 Valves 47a, 47b Decontamination liquid Supply port 48 Decontamination liquid discharge port 51 Blower (temperature control means)
52 Heater (Temperature adjusting means)
55 Bubble generator 56 Bubbles 68, 68a, 68b, 68c, 68d, 68e, 68f, 69, 69d, 70, 71, 72 Decontamination liquid flow 73 Liquid surface

Claims (5)

A PLR vertical pipe that transports coolant from the recirculation pump upward, a PLR horizontal pipe that is installed approximately horizontally above the PLR vertical pipe and around the reactor pressure vessel, and above the PLR horizontal pipe A reactor recirculation system pipe having a PLR riser pipe installed;
A decontamination pipe formed in a loop with respect to the reactor recirculation pipe;
And a temperature adjusting means for locally adjusting the temperature of at least one of the PLR horizontal pipe and the PLR riser pipe. The temperature adjusting means adjusts the temperature so that the average temperature of the decontamination liquid in the PLR horizontal pipe and the PLR riser pipe decreases as the temperature of the decontamination liquid increases from the upper end of the PLR vertical pipe. Decontamination equipment for nuclear power plants in Japan. A first decontamination bypass pipe branched from the decontamination pipe and connected to the PLR vertical pipe;
A bypass heater for heating the decontamination liquid in the first decontamination bypass pipe;
The decontamination apparatus for facilities in a nuclear power plant according to claim 1, further comprising: 2. The decontamination apparatus for facilities in a nuclear power plant according to claim 1, further comprising a bubble generation device for causing bubbles to be contained in a decontamination liquid in a PLR vertical pipe of the reactor recirculation system piping. A second decontamination bypass pipe branched from an injection pipe for injecting a decontamination liquid into the decontamination pipe and connected to a PLR vertical pipe of the reactor recirculation system pipe;
The decontamination that communicates with the second decontamination bypass pipe, protrudes into the PLR vertical pipe from the connecting portion between the second decontamination bypass pipe and the PLR vertical pipe, and has a tip bent upward in the PLR vertical pipe A liquid injection tube;
The decontamination apparatus for facilities in a nuclear power plant according to claim 1, further comprising:

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