JPS61288197A - Steam drier for nuclear reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a nuclear steam dryer suitable for a steam dryer installed in a boiling water nuclear reactor or a moisture separator of a turbine system, and particularly , relates to a nuclear steam dryer that has been improved to enable decontamination of the steam dryer unit.

[Technical background of the invention and its problems]

A conventional steam dryer installed in a boiling water nuclear reactor is configured as shown in FIG. 2, and is placed above a reactor core (not shown) in the reactor pressure vessel 1. That is, steam dryer 2
has its lower end immersed in the reactor water surface W, and separates the cylindrical skirt 3 from the moisture of the wet steam rising inside the reactor.
a steam dryer unit 4 for removal and a unit hood 5 for guiding the wet steam to this steam dryer unit 4;
and has.

As shown in the perspective view of FIG. 3, a plurality of steam dryer units 4 are vertically arranged in parallel on a circular bottom plate 6, and a plurality of tie bars are connected between the upper end surfaces of adjacent steam dryer units 4. 7 to prevent it from falling over. An annular support ring 8 is fixed to the outer periphery of the bottom plate 6, and as shown in FIG. 2, this support ring 8 is placed on a plurality of brackets 9 protruding from the inner wall of the reactor pressure vessel 1. As a result, the steam dryer 2 is placed above the reactor core.

Furthermore, as shown in FIG. 3, a plurality of seismic blocks 10 are fixed to the outer periphery of the support ring 8 at appropriate intervals in the circumferential direction, and these blocks 10 are fitted into the fitting portions of the brackets 9. By doing so, rotation of the steam dryer 2 in the circumferential direction is restrained in the event of an earthquake or the like.

The upper end of the support ring 8 is fixed to a cylindrical skirt 1 having a lower end ring 11 attached to the lower end thereof, and the lower ends of a plurality of drain pipes 12 are respectively penetrated through the outer peripheral wall of the skirt 3. The outer peripheral wall 3 is formed into a drain channel 13 that guides the dripping direction of drain discharged from each drain pipe 12.

The steam dryer unit 4 is constructed as shown in the partially enlarged perspective view of FIG. It is erected. The corrugated sheet unit 15 has a large number of corrugated sheets 15a which are bent in a corrugated manner so that the waves are continuous in the width direction, and are arranged side by side in the thickness direction at intervals, and the lower end of the corrugated sheet unit 15 The unit cover 16
covered by. The wet steam generated in the reactor core and rising is guided by the unit hood 5 and passes through the gaps between adjacent corrugated plates 15a along the width direction as shown by the broken line arrows. During this passage, moisture in the steam is transferred to the corrugated plate 1.
5a and is separated, condensed into a drain, and dripped onto the bottom plate 6 along each corrugated plate 15a. For this purpose, the drain is guided to the drain pipe 12 that opens on the bottom plate 6, drips down the drain channel 13, and returns to the reactor pressure vessel.
It is returned to the reactor water surface W inside.

By the way, the steam dryer 2 has a plurality of hanging ears 17 (third
(see figure) is installed (J), and when hoisting it into the reactor pressure vessel 1 or lifting it out of the reactor pressure vessel 1, a hanging lobe 18 etc. is attached to each hanging lug 17 as shown in Fig. 5. It can be installed and hung.

When inspecting the inside of the reactor pressure vessel 1 or replacing fuel in the reactor core, use the upper cover 1a of the reactor pressure vessel 1 (see Figure 2).
It is necessary to remove the steam dryer 2 from inside the reactor pressure vessel 1.

In such a case, as shown in FIG. It is suspended from the inside of the furnace pressure vessel 1, moved to the equipment storage bureau 2o as shown by the arrow in the figure, and stored.The reference numeral 21 in the figure is a fuel pool.

However, since this steam dryer 2 is radioactively contaminated, workers who remove, install, or carry it in and out of the steam dryer 2, as well as workers who perform loosening work in the vicinity of these operations, are exposed to increased radiation exposure. There is a fear.

The reason why this steam dryer 2 is contaminated with radioactivity is that rust and dust, which is tinged with radioactivity induced in the reactor core, adheres to the inner and outer surfaces of the steam dryer 2 during reactor operation. As the Wfd increases, the radioactive contamination of the steam dryer 2 increases.

Therefore, in order to reduce the amount of radiation exposure for such workers, the equipment storage boule 20 may be washed with water to remove radioactive contamination from the steam dryer 2.

However, although this makes it possible to wash off rust, dust, etc. adhering to the outer surface of the steam dryer 2, it is impossible to wash the inside.

In particular, the corrugated plate unit 15 of the steam dryer unit 4 easily captures rust and dust due to its shape, and the captured rust and dust cannot be expected to be washed away by the flow of steam. Because the surface area of
Among the entire steam dryer 2, the inside of the steam dryer unit 4 is contaminated with the most radioactivity.

However, in the conventional example, the inside of the steam dryer unit 4 could not be decontaminated.

[Purpose of the invention]

The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a nuclear steam dryer that can decontaminate the inside of the steam dryer unit with a simple configuration.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides a nuclear power steam dryer for passing steam through the steam dryer unit to separate and remove moisture thereof, which is installed in the above-mentioned FFI air dryer unit. It has a sparge 17 mechanism that sprays a decontamination material such as water inside, and a guide connector that guides the decontamination material to this sparger mechanism, and a supply pipe that connects this guide connector to a source of decontamination material such as water. The device is characterized in that it is configured so that it can be connected to the device, and is configured to be able to be sealed.

(Embodiments of the Invention) Examples of the present invention will be described below with reference to FIG.

An embodiment of the nuclear steam dryer according to the present invention has a steam dryer unit configured as shown in FIG.
Since the configuration other than this is the same as that of the conventional example described above, the explanation of the overlapping parts will be omitted.

That is, in this embodiment, a steam dryer unit 30 is configured as shown in the perspective view of the main part in FIG. It is erected by sandwiching the left and right sides of the lower end.

The corrugated plate unit 33 is constructed by arranging a large number of corrugated plates 33a, each of which is bent into a corrugated shape so that the waves are continuous in the width direction, at a required interval in the thickness direction. On one side, a perforated plate 34 with a large number of holes is attached to almost the entire surface of the side. On the outside of this perforated plate 34, an arc-shaped unit hood 35 that is convex outward is provided at a required interval.
is provided to guide the flow of steam in the direction shown by the dashed arrow.

On the other hand, on the upper end surface of the corrugated plate unit 33, there is a sparger mechanism 3 that sprays a decontamination material such as water onto the corrugated plate unit 1-33.
6, and this sparger mechanism 36 covers a spray plate 37 and a unit cover 38, which are fixed over almost the entire length on the upper end surface of the corrugated plate unit 33. The spray plate 37 has a front edge and a rear edge in the width direction bent downward at right angles to form a cross-sectional shape, and is erected with the U-shaped frontage facing downward. A large number of spray holes 37a penetrating in the thickness direction of the plate are bored in the flat plate part, and decontamination materials such as water are applied to the corrugated plate unit 3 below through these spray holes 37a.
It is designed to spray towards 3.

The upper surface of this spray plate 37 is completely and liquid-tightly covered by a unit cover 38 having an opening-shaped cross section. That is, the unit cover 38 stands with its U-shaped opening facing the top surface of the spray plate 37, and the connection portion with the side edge of the spray plate 37 is liquid-tightly connected, so that the spray plate 37 and the unit 1- A decontamination material such as water is supplied to the space between the cover 38 and the cover 38 . Further, the upper end of the unit hood 35 is integrally or integrally connected to the lower end of one side of the unit cover 38, and a plurality of guide connectors 39 are connected to the upper surface of the unit cover 38.
It is installed through the. These guide connectors 39 are formed in the shape of short tubes, and the upper ends protruding upward from the upper surface of the unit cover 39 are configured to be connectable to a water hose (supply pipe) not shown, and are connected to a source of decontamination material such as water. A water hose is connected to guide decontamination materials such as water into the unit cover 38.

Further, the upper ends of these guide connectors 39 are designed to be sealed with a closing plug or the like (not shown) during reactor operation. In FIG. 1, reference numeral 40 is a tie bar that connects adjacent steam dryer units 30 to prevent them from falling over, and 41 is a tie bar that opens at one end below the corrugated sheet unit 33 and is attached to the bottom plate 31. This is a drain pipe installed through the drain pipe 41, and the drain dripping onto the bottom plate 31 along the corrugated plate unit 33 is drained through the drain pipe 41.

A plurality of steam dryer units 30 configured in this manner are assembled into a nuclear steam dryer.

Next, the operation of this embodiment will be mainly described with respect to the steam dryer unit 30.

During reactor operation, wet steam generated in the reactor core rises in the reactor pressure vessel and is introduced into the unit hood 35 of the steam dryer unit 30 as shown by the broken line arrow in FIG. Here, the flow direction of the steam is turned laterally and passes through the gap of the corrugated plate unit 33. During this passage, the moisture in the wet steam collides with many corrugated plates 33a, is separated, condenses into a drain, and flows down along each corrugated plate 33a.
Drain is dripped onto the bottom plate 31. As a result, the water is returned to the reactor water in the reactor pressure vessel via the drain pipe 40 and the like.

When inspecting the inside of the reactor pressure vessel 1 (see FIG. 5) or replacing fuel in the reactor core, the air dryer 2 is lifted out, carried into the equipment storage boule 20, and stored. This equipment storage boule 20 may be empty without containing pool water, or, if filled with pool water, its water level may be lower than the top of the unit support 32 of the steam dryer unit 30. .

Thereafter, the closing plugs (not shown) of each guide connector 39 are removed, and water hoses connected to a source of decontamination material such as water (not shown) are connected to these guide connectors 39 to supply water. As a result, decontamination materials such as water are guided to each guide connector 39 and each unit cover 38
is supplied at the required pressure. Therefore, spray plate 3
A decontamination material such as water is sprayed from each spray hole 37a of 7 toward almost the entire upper end surface of the corrugated plate unit 33.

Rust and dust adhering to the outer surface of the corrugated plate unit 33 are washed away by this spray water, and are washed away onto the bottom plate 31 between the unit supports 32. As a result, rust and dust are returned to the reactor water surface together with the spray water through each drain pipe 41, drain channel, etc.

In this way, this embodiment can remove radioactive contaminants adhering to the steam dryer unit 30 and decontaminate it.
11ffi can be reduced.

In addition, although the above-mentioned embodiment described an example in which the spray plate 37 was provided inside the unit cover 38 as the sparger mechanism 36, the present invention is not limited to this.
For example, a spray pipe having a large number of spray holes for spraying a decontamination material such as water may be provided inside the unit cover 38, and one end of this spray pipe may be connected to the guide connector 39.

According to this embodiment, the inside of the steam dryer unit 30 can be decontaminated similarly to the above embodiment.

Further, in the above embodiments, the case where the present invention is applied to a steam dryer disposed inside a boiling water nuclear reactor has been described, but the present invention is not limited to this. For example, the invention is not limited to this. It can also be applied to moisture separators in plant turbine systems.

〔Effect of the invention〕

As explained above, the present invention provides a nuclear steam dryer that passes steam through the steam dryer unit and separates and removes its moisture. It has a sparger mechanism that sprays a decontamination material, and a guide connector that guides the decontamination material to the sparger mechanism, and the guide connector is configured to be connectable to a supply pipe connected to a source of decontamination material such as water. In addition, it is configured to be airtight.

Therefore, according to the present invention, radioactive contaminants are removed by spraying a decontamination material such as water inside the steam dryer unit,
Since it can be decontaminated, this steam dryer unit 1~
[f]
It is possible to reduce fi.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of the main parts of an embodiment in which the present invention is applied to a steam dryer for a boiling water reactor, and FIG. 2 shows a conventional steam dryer for a boiling water reactor. 3 is a partially cutaway perspective view of the conventional steam dryer shown in FIG. Fig. 5 is a perspective view of the main parts of the steam dryer unit shown with a partial cutaway, and Fig. 5 is an explanatory view showing a partial longitudinal cross-section of the steam dryer taken out from the reactor pressure vessel and stored in the equipment storage pool. It is. 30... Steam dryer unit, 31... Bottom plate, 32
... Unit sabot-1-133 ... Corrugated plate unit,
36... Sparger mechanism, 37... Spray plate, 3
8...Unit cover, 39...Guide connector. $ I Figure Sheep 3 times Drainage 4 times $ Q Figure

Claims (1)

[Scope of Claims] 1. In a nuclear steam dryer that separates and removes moisture by passing steam through the steam dryer unit, a device installed in the steam dryer unit to remove water, etc. It has a sparger mechanism that sprays a dyeing material, and a guide connector that guides the decontamination material to the sparger mechanism, and the guide connector is configured to be connectable to a supply pipe connected to a source of decontamination material such as water. A steam dryer for nuclear power use, characterized in that it is configured to be airtight. 2. In the sparger mechanism, a plate-shaped spray plate with a plurality of spray holes is arranged above the upper end surface of the corrugated plate unit with a required space, and the upper surface of the spray plate is approximately The nuclear power steam according to claim 1, wherein a unit cover covering the entire surface is liquid-tightly covered, and a gap between the unit cover and the spray plate is formed as a flow path for a decontamination material such as water. Dryer. 3. The sparger mechanism includes a tubular spray pipe with a plurality of spray holes provided above the upper end surface of the corrugated plate unit, and a supply connector is connected to the spray pipe as claimed in claim 1. Nuclear steam dryer described in . 4. The nuclear steam dryer according to claim 1, wherein the supply connector is provided through the unit cover.