JP7034349B1 - Cleaning device for steam separator and its cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning technique of a steam separator capable of surely removing dust, dust and the like accumulated inside. SOLUTION: A cleaning device 31 has a first flange 41 that detachably seals a lower end opening 28 of a constituent unit 20 of a steam separator, and a cleaning liquid that is connected to the first flange 41 and is filled inside the constituent unit 20. First supply pipe 51, for supplying the above. [Selection diagram] FIG. 4

Description

An embodiment of the present invention relates to a technique for cleaning a steam separator used in a boiling water reactor.

An air-water separator is a device that removes droplets from steam containing droplets. When steam containing droplets enters the turbine, turbine efficiency is significantly reduced. Therefore, the boiling water reactor separates the droplets from the outside and the steam from the inside by the centrifugal separation action by guiding the steam mixed with steam from the core to the steam separator and giving it a swirling flow. The steam from which the droplets have been removed is further passed through a desiccator and guided to the turbine, and the separated droplets are returned to the water in the upper part of the core.

Japanese Unexamined Patent Publication No. 2013-120068

If there is a concern that the air-water separator will be stored in the air during the construction work of the nuclear power plant or during the suspension period, and there is a concern that dust and dirt will accumulate inside it, cleaning will be performed to remove them. However, the brackish water separator has a complicated internal structure and is as long as about 5 m in the longitudinal direction. For this reason, when dust or dust gets inside the steam separator, it is difficult to reliably remove them.

The embodiment of the present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a cleaning technique for an air-water separator capable of reliably removing dust, dust, etc. accumulated inside. ..

In the cleaning device of the air-water separator according to the embodiment, the first flange that detachably seals the lower end opening of the constituent unit of the air-water separator and the first flange are connected to fill the inside of the constituent unit. A first supply pipe for supplying the cleaning liquid is provided.

An embodiment of the present invention provides a cleaning technique for a steam separator capable of reliably removing dust, dust, etc. accumulated inside.

Longitudinal section of the pressure vessel of a boiling water reactor. (A) Vertical sectional view of the steam separator, (B) Horizontal sectional view of the steam separator. Schematic diagram of the vertical cross section of the constituent unit of the steam separator. The side view of the 1st cleaning apparatus of the steam separator which concerns on embodiment. The explanatory view of the cleaning method of the steam separator by the 1st cleaning apparatus. (A) A vertical sectional view of the second cleaning device of the steam separator according to the embodiment, and (B) a top view of the second flange of the second cleaning device. The process drawing of the cleaning method of the steam separator which concerns on embodiment.

Hereinafter, prior to the description of the air-water separator cleaning device according to the embodiment of the present invention, the air-water separator 18 and other related structures to which the present embodiment is applied will be described with reference to the accompanying drawings. FIG. 1 is a vertical sectional view of a pressure vessel 12 of a boiling water reactor 10.

In a boiling water reactor 10 (BWR), the coolant injected into the pressure vessel 12 from the water supply nozzle 11 passes through the downcomer 14 formed on the outside of the core shroud 13 and the inside of the pressure vessel 12 to the core. Enter the bottom. Therefore, the coolant reverses the flow direction, flows upward inside the core shroud 13, takes heat from the fuel assembly 15, and becomes a two-phase flow in which the gas phase and the liquid phase coexist.

A steam separator 18 is erected on the shroud head 16 that closes the upper opening of the core shroud 13 via a plurality of stand pipes 17. A steam dryer 19 is arranged above the steam separator 18, and both of them remove droplets in the steam.

The steam from which the water has been removed is output from the steam nozzle 40 and supplied to a turbine (not shown). The separated droplets travel outside the shroud head 16 and return to the downcomer 14, and are again supplied from the lower part of the core to the inside of the core shroud 13.

FIG. 2A is a vertical cross-sectional view of the steam separator 18 (AA cross-sectional view of FIG. 2B). FIG. 2B is a horizontal cross-sectional view thereof (B-B cross-sectional view of FIG. 2A). The shroud head 16 is removed from the upper opening of the core shroud 13 (FIG. 1) and transferred in an integrated state with the steam separator 18. The air-water separator 18 is composed of a plurality of constituent units 20, and as shown in FIG. 2B, each stand pipe 17 stands most closely on the upper surface of the shroud head 16.

FIG. 3 is a schematic view of a vertical cross section of the constituent unit 20 of the steam separator. The illustrated configuration unit 20 is composed of a stand pipe 17, a first stage 21, and a second stage 22. Then, the steam containing the droplets input from the lower end opening 28 of the constituent unit 20 is separated into the droplets in two stages of the first stage 21 and the second stage 22, and the droplets are removed from the upper end opening 29 of the constituent unit 20. The steam is output.

When the steam (including droplets) rising from the lower end opening 28 provided in the shroud head 16 passes through the fixed blade 23, it becomes a swirling flow and enters the first stage 21. The droplets are pressed against the inner peripheral surface of the inner cylinder 25a of the first stage 21 and further rise due to the centrifugal force accompanying the swirl, and the outer peripheral surface of the inner cylinder 25a and the outer cylinder 27a are provided by the guide structure provided at the terminal position 26a. Guided by the gap with the inner peripheral surface of the body, it descends due to gravity and is discharged to the outside of the constituent unit 20.

The vapor (including droplets) that has passed through the first stage 21 enters the second stage 22 while maintaining the swirling flow. Then, the droplet is pressed against the inner peripheral surface of the inner cylinder 25b of the second stage 22 by the centrifugal force accompanying the swirl and further rises, and the outer peripheral surface and the outer side of the inner cylinder 25b are further provided by the guide structure provided at the terminal position 26b. Guided by the gap between the inner peripheral surface of the cylinder 27b and the inner peripheral surface, the cylinder 27b descends due to gravity and is discharged to the outside of the constituent unit 20. The steam that has passed through the second stage 22 is output from the upper end opening 29 of the constituent unit 20. In some cases, a third stage may be provided above the second stage 22.

FIG. 4 is a side view of the first cleaning device 31 of the steam separator according to the embodiment. In this way, the first cleaning device 31 is connected to the first flange 41 that detachably seals the lower end opening 28 of the constituent unit 20 of the steam separator, and is connected to the first flange 41 to fill the inside of the constituent unit 20. A first supply pipe 51 for supplying the cleaning liquid is provided.

An O-ring 43 is provided at the edge of the first flange 41 so as to be in close contact with the inner peripheral surface of the stand pipe 17 and to ensure airtightness so that the filled cleaning liquid does not leak. The washing water supplied from the lower end opening 28 of the constituent unit 20 may be filled up to the upper end opening 29 (FIG. 3). Therefore, the first flange 41 installed in the lower end opening 28 of the stand pipe 17 needs to have a sealing strength that can sufficiently withstand such head pressure.

The first supply pipe 51 has an upper end connected to the first flange 41 and has a branch 53 in which the on-off valve 54 is arranged. An external supply source (not shown) for cleaning liquid is connected to the tip of the branch 53. The branch 53 is also provided with a discharge unit (not shown) for discharging the cleaning liquid filled in the constituent unit 20 to the outside. Further, the lower end 55 of the first supply pipe 51 is configured to abut on the tip of the height-adjustable support member 35.

FIG. 5 is an explanatory diagram of a cleaning method of the steam separator 18 by the first cleaning device 31. FIG. 5 is an enlargement of the portion surrounded by the alternate long and short dash line 30 in FIG. 2 (A). In this way, the steam separator 18 to be cleaned is arranged on the work floor 37 via the pedestal 36, and an appropriate work space is secured inside the work floor 37.

As described above, the lower end opening 28 of the steam separator 18 has a different height depending on the connection position of the stand pipe 17 because the shroud head 16 is curved. For this purpose, the first cleaning device 31 is attached to each lower end opening 28 after adjusting the height of the support member 35. Although the description is omitted, in order to attach the first cleaning device 31 and the second cleaning device 32 described later, a scaffold for work may be assembled with a pipe or a plate.

FIG. 6A is a vertical sectional view of the second cleaning device 32 of the steam separator according to the embodiment. In this way, the second cleaning device 32 has a second flange 42 that is detachably installed in the upper end opening 29 of the constituent unit 20 and a foreign substance (foreign matter that is connected to the second flange 42 and adheres to the inner peripheral surface of the constituent unit 20). It is provided with a second supply pipe 52 for supplying a gas that blows off droplets, dust, dust, etc.).

The second flange 42 is detachably installed in the upper end opening 29 of the constituent unit 20 via the intermediary member 46. The second flange 42 and the upper end opening 29 do not need to be sealed like the first flange 41 and the lower end opening 28, and have a function of ensuring the position accuracy of the gas injection end 56 of the second supply pipe 52 as described later. ..

The injection end 56 of the second supply pipe 52 in the embodiment faces the direction of directly injecting the terminal position 26 of the inner cylinder 25 located inside the outer cylinder 27 of the constituent unit 20. The shape of the gas injection end 56 is not particularly limited, and is appropriately adopted as long as it has a function of injecting gas to blow off foreign matter adhering to the inner peripheral surface of the constituent unit 20. The second supply pipe 52 is provided on a slide bearing 48 provided along the axis of rotational symmetry of the second flange 42. Further, a handle 45 operated by a worker to rotate and a stopper 47 are fixed to the second supply pipe 52.

As a result, the worker can stably inject gas to the entire circumference of the end position 26 of the inner cylinder 25 by pushing the handle 45 downward and rotating the handle 45. As a result, residual dust, dust, and the like can be discharged to the outside of the constituent unit 20 from the terminal position 26 of the inner cylinder 25 to the gap formed inside the outer cylinder 27.

Further, the fixed positions of the handle 45 and the stopper 47 can be changed with respect to the second supply pipe 52. As a result, the position of the gas injection end 56 can be adjusted according to the plurality of terminal positions 26 (26a, 26b) (see FIG. 3) existing in the longitudinal direction of the constituent unit 20. Further, by separately preparing a dedicated second supply pipe 52 corresponding to each end position 26 (26a, 26b) without changing the fixed position of the handle 45 or the stopper 47, the gas injection end 56 can be provided. The position may be adjusted.

FIG. 6B is a top view of the second flange 42 of the second cleaning device 32. As described above, the second flange 42 is provided with a peephole 44, and the handle 45 can be operated while checking the position of the gas injection end 56.

A method for cleaning the steam separator according to the embodiment will be described with reference to the process diagram of FIG. 7 (see other drawings as appropriate). First, as shown in FIG. 4, the lower end opening 28 of the constituent unit 20 of the steam separator is sealed by the first flange 41 of the first cleaning device 31 (S11). Then, the cleaning liquid is supplied from the first supply pipe 51 connected to the first flange 41 to fill the inside of the constituent unit 20 (S12).

Next, the cleaning liquid filled in the constituent unit 20 is discharged (S13), and then the second flange 42 of the second cleaning device 32 is installed in the upper end opening 29 of the constituent unit 20 as shown in FIG. 6 (A). (S14). Then, gas is supplied from the second supply pipe 52 connected to the second flange 42 to blow off the foreign matter adhering to the inner peripheral surface of the constituent unit 20 (S15). Then, the position of the injection end 56 of the second supply pipe 52 is changed to concentrate the gas injection at the place where the foreign matter easily adheres or stays (END).

According to the cleaning device for the steam separator of at least one embodiment described above, the inside of the constituent unit of the steam separator is filled with the cleaning liquid to surely remove dust and dirt accumulated inside the cleaning device. It becomes possible to do.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

For example, in the present embodiment, the inside of the constituent unit 20 is filled with a cleaning liquid by the first cleaning device 31, the cleaning liquid is discharged, and then the inner peripheral surface of the constituent unit 20 is gas-injected by the second cleaning device 32. showed that. As another embodiment, there is also an example in which the cleaning liquid is only filled and discharged by the first cleaning device 31 and the gas injection by the second cleaning device 32 is omitted.

10 ... boiling water reactor, 11 ... water nozzle, 12 ... pressure vessel, 13 ... core shroud, 14 ... downcomer, 15 ... fuel assembly, 16 ... shroud head, 17 ... stand pipe, 18 ... steam separator , 19 ... Steam dryer, 20 ... Constituent unit, 21 ... 1st stage, 22 ... 2nd stage, 23 ... Fixed blade, 25 (25a, 25b) ... Inner cylinder, 26 (26a, 26b) ... Termination position, 27 (27a, 27b) ... outer cylinder, 28 ... lower end opening, 29 ... upper end opening, 31 ... first cleaning device (cleaning device), 32 ... second cleaning device (cleaning device), 35 ... support member, 36 ... pedestal, 37 ... work floor, 40 ... steam nozzle, 41 ... first flange, 42 ... second flange, 43 ... O-ring, 44 ... hole, 45 ... handle, 46 ... mediator, 47 ... stopper, 48 ... sliding bearing, 51. ... 1st supply pipe, 52 ... 2nd supply pipe, 53 ... branch, 54 ... on-off valve, 55 ... lower end, 56 ... injection end.

Claims (7)

The first flange that detachably seals the lower end opening of the component unit of the steam separator,
A cleaning device for a brackish water separator, comprising a first supply pipe connected to the first flange and supplying a cleaning liquid to be filled inside the constituent unit. In the cleaning device for the steam separator according to claim 1,
In the first supply pipe, the lower end opposite to the upper end connected to the first flange is a cleaning device for an air-water separator that abuts on the tip of a height-adjustable support member. In the steam separator cleaning device according to claim 1 or 2.
A second flange detachably installed in the upper end opening of the constituent unit,
A cleaning device for an air-water separator, comprising a second supply pipe connected to the second flange and supplying a gas that blows off foreign matter adhering to the inner peripheral surface of the constituent unit. In the cleaning device for the steam separator according to claim 3,
The second supply pipe is rotatably connected to the second flange, and is a cleaning device for a steam separator to which a handle rotated by an operator is fixed. In the cleaning device for the steam separator according to claim 4,
The second supply pipe is a cleaning device for an air-water separator in which the injection end of the gas is directed in the direction of directly injecting the terminal position of the inner cylinder located inside the outer cylinder of the constituent unit. In the cleaning device for the steam separator according to claim 5.
The second supply pipe is a cleaning device for an air-water separator whose position of the injection end of the gas is adjusted according to a plurality of terminal positions existing in the longitudinal direction of the constituent unit. The process of sealing the lower end opening of the component unit of the steam separator with the detachable first flange, and
A step of supplying a cleaning liquid from a first supply pipe connected to the first flange and filling the inside of the constituent unit, and a step of filling the inside of the constituent unit.
A step of installing a detachable second flange in the upper end opening of the constituent unit after discharging the cleaning liquid filled in the constituent unit.
A method for cleaning an air-water separator, comprising a step of supplying gas from a second supply pipe connected to the second flange and blowing off foreign matter adhering to the inner peripheral surface of the constituent unit.

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