JPH0954184A - Reactor containment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a corrosion resistive film free from rust and swell for a long time. SOLUTION: Inside a reactor containment 1 of a boiling water reactor plant, a drywell and a pressure suppression chamber 4 are formed. In the pressure suppression chamber 4, pool water is contained. When steam is supplied from inside the drywell to the inside of the pressure suppression chamber 4, the steam is to be cooled and condensed. On the inner wall of the pressure suppression chamber 4, a corrosion resistive film 15 such as organic zinc-rich film 16 and epoxy resin coat film 17 is formed. Thus, zinc powder in the organic zinc-rich film 16 is covered with organic materials and so zinchydroxide is hardly formed and as the results, the corrosion resistive film 15 is maintained in intact state for a long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor containment vessel having a structure in which pool water is contained in a pressure suppression chamber.

[0002]

FIG. 5 shows a schematic structure of a boiling water reactor plant. Here, the reactor containment vessel 1
A diaphragm floor 2 is provided therein, a dry well 3 corresponding to a container accommodating chamber is formed in the upper part of the reactor containment vessel 1, and a pressure suppression chamber 4 is formed in the lower part of the reactor containment vessel 1. Are sectioned. A reactor pressure vessel 5 is housed in the dry well 3.

A plurality of vent pipes 6 are accommodated in the pressure suppression chamber 4, and the upper end of each vent pipe 6 penetrates the diaphragm floor 2 and is located in the dry well 3 so that each vent pipe 6 can be accommodated. The lower end is immersed in pool water 7 in the pressure suppression chamber 4. When the steam in the reactor pressure vessel 5 is filled in the dry well 3 due to an accident, the steam is guided into the pool water 7 through the plurality of vent pipes 6,
It is designed to coagulate by cooling. The pool water 7 is also used as a residual heat removal system water source and an emergency core cooling system water source in addition to cooling and condensing steam.

A main steam line 9 and a water supply line 10 are connected to the reactor pressure vessel 5 in addition to a recirculation line 8 for recirculating the temporary coolant in the pressure vessel 5, and the main steam line 9 and the water supply line 10 are connected. Are led out of the reactor containment vessel 1. Then, the steam generated in the reactor pressure vessel 5 is guided from the main steam line 9 to the turbine 12 for power generation via the pressure control valve 11, passes through the turbine 12, and is cooled and condensed by the condenser 13, Reactor pressure vessel 5 again via feed water heater 14 inserted in feed line 10.
Water is supplied inside.

In this structure, a rolled steel plate is used as the material of the inner wall of the pressure suppression chamber 4, and the rolled steel plate is provided with a corrosion-resistant coating film for preventing corrosion by the pool water 7. Conventionally, this anticorrosion coating is prepared by undercoating an inorganic zinc-rich paint on the surface of a rolled steel sheet, intermediately coating an epoxy paint on the surface of the inorganic zinc-rich paint, and top-coating an epoxy paint on the surface of the epoxy paint. The film thickness of the inorganic zinc-rich coating film is 65 μm,
The film thickness of each epoxy coating film is set to 100 μm.

The inorganic zinc-rich paint is a solution of alkyl silicate added with zinc dust (rust preventive pigment), and the alkyl silicate functions as a binder for wrapping and bonding zinc dust. The inorganic zinc-rich paint is "SD Zinc 15" manufactured by Kansai Paint Co., Ltd.
00A (product name) "is used, and this product has a weight ratio of the alkyl silicate solution and the zinc powder of" 80: 2 ".
It is 0 ".

In the conventional anticorrosion coating film, the inorganic zinc-rich coating film absorbs water to increase its activity, and alkaline zinc hydroxide (Zn (OH) ₂ ) is likely to be produced. For this reason, swelling occurs between the layers of the inorganic zinc-rich coating film and the epoxy coating film in 3 to 5 years, and if the swelling is left unattended, the swelling grows due to long-term water immersion, resulting in cracks or rust. This will corrode the material. Therefore, the entire surface of the anticorrosion coating film is repainted before the rolled steel sheet, which is the base material, corrodes.

On the other hand, in the reactor, after the pool water 7 is transferred to the container, the rust on the inner wall of the pressure suppression chamber 4 is removed and the blasting is performed, the undercoat, intermediate coat and top coat are applied. It is necessary to carry out to form an anticorrosion coating film. Therefore, it is necessary to perform complicated work in the closed pressure suppression chamber 4, and it is necessary to prepare for the worker not to be exposed to radiation, resulting in enormous time and cost.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a reactor containment vessel having a corrosion-resistant coating film that does not cause rust or swelling for a long period of time.

[0010]

According to a first aspect of the present invention, there is provided a reactor containment vessel comprising: a vessel housing chamber in which a reactor pressure vessel is housed;
Pool pressure is accommodated, and a pressure suppression chamber that cools and condenses the steam with the supply of steam from the container storage chamber,
With an anticorrosion coating provided on the inner wall of this pressure suppression chamber,
The anticorrosion coating film is characterized in that it comprises an organic zinc-rich coating film formed on the inner wall of the pressure suppression chamber and an epoxy resin coating film formed on the surface of the organic zinc-rich coating film. According to the above means, since the zinc dust in the organic zinc-rich coating film is wrapped with the organic substance, it is prevented that the coating film reacts with the absorbed water to generate hydrogen, and alkaline zinc hydroxide (Zn (OH) ₂ ) is less likely to be generated. Therefore, swelling does not occur between the organic zinc-rich coating film and the epoxy coating film, and as a result, the anticorrosion coating film is kept in a healthy state for a long time.

According to a second aspect of the present invention, there is provided a reactor containment vessel in which a vessel accommodating chamber in which a reactor pressure vessel is accommodated, pool water is accommodated, and steam is supplied from the vessel accommodating chamber to cool the steam. A pressure suppressing chamber that agglomerates and an anticorrosive coating film provided on the inner wall of the pressure suppressing chamber are provided.
It is characterized in that it is made of a thick film type epoxy resin coating film formed on the inner wall of the pressure suppression chamber. According to the above means, the zinc dust in the anticorrosion coating film is eliminated, so that alkaline zinc hydroxide is not produced. Therefore, the anticorrosion coating does not swell, and as a result, the anticorrosion coating is kept in a healthy state for a long period of time.

The reactor containment vessel according to claim 3 is characterized in that a sacrificial anode is provided on the inner wall of the pressure suppression chamber. According to the above means, the oxygen in the pool water is combined with the sacrificial anode to oxidize the sacrificial anode, so that the oxidation of the wall surface of the pressure suppression chamber is prevented.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will now be described with reference to FIG.
A description will be given based on FIG. Since the schematic structure of the boiling water reactor plant is the same as that shown in FIG. 5, the description thereof will be omitted. Hereinafter, the corrosion-resistant coating film 15 applied to the inner wall of the pressure suppression chamber 4 will be described.
Will be described in detail.

First, in FIG. 1, an organic zinc rich coating film 16 having a film thickness of 65 μm is formed on the inner wall of the pressure suppression chamber 4. The organic zinc-rich coating film 16 has the following composition and is made of "SD zinc 500 (trade name)" manufactured by Kansai Paint Co., Ltd.

Base: Lead powder 72.0 (percentage by weight) Face agent 3.5 (percentage by weight) Epoxy resin varnish 17.0 (percentage by weight) Additive 2.5 (percentage by weight) Hardener: Polyamide resin varnish 5.0 (weight percentage)

On the surface of the organic zinc-rich coating film 16,
A first epoxy resin coating film 17a having a film thickness of 100 μm is formed. The first epoxy resin coating film 17a contains a corrosion-resistant pigment such as lead or zinc, and is formed by spraying an epoxy resin coating on the surface of the organic zinc rich coating film 16. Also, the first epoxy resin coating film 1
A second epoxy resin coating film 17b having a film thickness of 100 μm is formed on the surface of 7a. The second epoxy resin coating film 17b is colored and is formed by spraying an epoxy resin paint on the surface of the first epoxy resin coating film 17a. Incidentally, reference numeral 17 denotes an epoxy resin coating film composed of a first epoxy resin coating film 17a and a second epoxy resin coating film 17b.

According to the above embodiment, the anticorrosion coating 15 is formed by superposing the epoxy resin coating 17 on the surface of the organic zinc rich coating 16. Therefore, since the zinc dust in the organic zinc-rich coating film 16 is wrapped with the organic substance, it is prevented that the anticorrosion coating film 15 reacts with the absorbed water to generate hydrogen, and alkaline zinc hydroxide is generated. It becomes difficult to be done. Therefore, swelling does not occur between the organic zinc-rich coating film 16 and the first epoxy resin coating film 17a, and as a result, the anticorrosion coating film 15 is kept in a healthy state for a long period of time.

As a result, the cycle for recoating the anticorrosion coating 15 becomes long, so that the frequency of performing complicated work in the closed pressure suppression chamber 4 and the frequency of making preparations to prevent radiation exposure by the operator are low. As a result, the time and cost for repainting the anticorrosion coating 15 are reduced. Along with this, the most important safety is also improved for the reactor plant.

As described above, the anticorrosion coating film 15 is soaked in the pool water 7 to cause swelling in the process of absorbing and swelling water, and as the swelling grows, it becomes cracks or rust to corrode the base metal. Let Therefore, in order to evaluate the swelling of the anticorrosion coating film 15, the anticorrosion coating film 1 is subjected to a temperature difference immersion test (deterioration acceleration test) in which a temperature difference is applied to the inner and outer surfaces of the anticorrosion coating film 15.
It is sufficient to simulate the usage environment of No. 5 and qualitatively determine the time until the anticorrosion coating film 15 swells. In addition, anticorrosion coating 15
In order to evaluate the corrosion resistance of the above, the time until rust is generated may be qualitatively obtained by a commonly used salt spray test.

FIG. 4 compares the results of the temperature difference immersion test and the salt spray test of the anticorrosion coating 15 with those of the conventional anticorrosion coating. As is clear from the figure, the conventional anticorrosive coating film swells in about 20 days, whereas the anticorrosive coating film 15 shows no swelling sign even after 100 days. In addition, the corrosion-resistant coating film 15 did not show rust even after 200 days, and it was confirmed that the corrosion-resistant coating film 15 had the same level of corrosion resistance as the conventional corrosion-resistant coating film. Here, the temperature difference immersion test was performed at 40 ° C. on one side and 20 ° C. on the other side of the anticorrosion coating 15.

In the first embodiment, the first epoxy resin coating film 17a and the second epoxy resin coating film 17b are used.
Although the thickness of the coating film is set to 100 μm, the thickness is not limited to this, and it is advantageous that the coating films 17a and 17b have a large film thickness in terms of corrosion resistance. However, the film thickness of the first epoxy resin coating film 17a and the second epoxy resin coating film 17b is preferably 100 to 200 [mu] m from the viewpoint of workability and sufficient corrosion resistance for the convenience of spray coating.

In the first embodiment, the film thickness of the organic zinc rich coating film 16 is set to 65 μm.
If there is a risk of deterioration of corrosion resistance, set the film thickness to 65μ.
It is better to set it slightly thicker than m. Further, in the above-mentioned first embodiment, the epoxy resin coating film 17 has a two-layer structure of the first epoxy resin coating film 17a and the second epoxy resin coating film 17b, but the present invention is not limited to this and three layers are provided. A structure or more or a single layer structure may be used.

Next, a second embodiment of the present invention will be described with reference to FIGS.
It will be described based on. The schematic structure of the boiling water reactor plant is the same as that shown in FIG.
A corrosion-resistant coating film 18 formed of a thick film type epoxy resin coating film (having a film thickness equal to or more than that of the conventional corrosion-resistant coating film and the corrosion-resistant coating film 15 of the first embodiment) applied to the inner wall of the pressure suppression chamber 4. Will be described in detail.

First, in FIG. 2, a first epoxy resin coating film 18a is formed on the inner wall of the pressure suppression chamber 4. The first epoxy resin coating film 18a is formed by spraying (lining) an epoxy resin coating on the inner wall of the pressure suppression chamber 4, and has a film thickness of 150 μm. The first epoxy resin coating film 18a contains a corrosion-resistant pigment such as lead or zinc, and is made of "Napco Barrier SP (trade name)" of Kansai Paint Co., Ltd.

A second epoxy resin coating film 18b is formed on the surface of the first epoxy resin coating film 18a. This second
The epoxy resin coating film 18b is the first epoxy resin coating film 18
It is formed by spraying an epoxy resin paint on the surface of a and has a film thickness of 150 μm. still,
The second epoxy resin coating film 18b is colored,
It consists of "Napco Barrier SP (trade name)" from Kansai Paint Co., Ltd.

According to the above embodiment, the anticorrosion coating film 18 is formed of a thick film type epoxy resin coating film. Therefore, the zinc dust in the anticorrosion coating film 18 disappears, so that alkaline zinc hydroxide is not produced. Therefore, the swelling of the anticorrosion coating 18 is eliminated, so that the cycle of recoating the anticorrosion coating 18 is prolonged, and as a result, the time and cost required for recoating the anticorrosion coating 18 are reduced. Along with this, the most important safety is also improved for the reactor plant. As shown in FIG. 4, the anticorrosion coating film 18 showed no swelling sign even after 100 days, and no rust was found after 200 days.

Next, a third embodiment of the present invention will be described with reference to FIGS.
It will be described based on. The same members as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, only different members will be described.

First, in FIG. 3, a plurality of sacrificial anodes 19 are attached to the inner wall of the pressure suppression chamber 4. Each of these sacrificial anodes 19 is made of a metal such as zinc or aluminum having a lower potential than the rolled steel plate (iron) that is the inner wall material of the pressure suppression chamber 4, and is welded or bolted to the inner wall of the pressure suppression chamber 4. Is connected in a conducting state. The sacrificial anode 19 may be one that is widely used for water pipes, gas pipes, coastal structures, seawater equipment, etc. buried in the ground, and it is necessary to use a dedicated one. There is no.

According to the above embodiment, a battery is formed between the rolled steel plate (the inner wall of the pressure suppression chamber 4) and each sacrificial anode 19, the sacrificial anode 19 having a large ionization tendency is the positive electrode, and the inner wall of the pressure suppression chamber 4 is the negative electrode. become. Therefore, oxygen in the pool water 7 is combined with the sacrificial anode 19 to oxidize the sacrificial anode 19, so that oxidation of the inner wall of the pressure suppression chamber 4 is prevented. Therefore, the pressure suppression chamber 4 is protected against corrosion at least until the sacrificial anode 19 is oxidized and consumed, so that the corrosion resistance is further improved. As shown in FIG. 4, the anticorrosion coating film 18 showed no swelling sign even after 100 days, and no rust was found after 200 days.

In the second and third embodiments described above, "Napco Barrier SP (trade name)" of Kansai Paint Co., Ltd. was used as the epoxy resin paint, but the epoxy resin paint is not limited to this, and for example, Kansai “Epomarin JW (trade name)” manufactured by Paint Co., Ltd. may be used. In the case of this configuration, the first epoxy resin coating film 18a and the second epoxy resin coating film 18a
The thickness of the epoxy resin coating film 18b is 150 μm (total film thickness 3
00 μm) is preferable.

In the second and third embodiments, the film thickness of the first epoxy resin coating film 18a and the second epoxy resin coating film 18b is set to 150 μm, but it is not limited to this. A thicker film thickness of each of the coating films 18a and 18b is advantageous in terms of corrosion resistance. However, the film thicknesses of the first epoxy resin coating film 18a and the second epoxy resin coating film 18b are 150 to 250 μm from the viewpoint of workability and sufficient corrosion resistance for the convenience of spray coating.
Is appropriate.

Further, in the second and third embodiments, the anticorrosion coating film 18 has a two-layer structure of the first epoxy resin coating film 18a and the second epoxy resin coating film 18b, but the invention is not limited to this. Instead, it may have a three-layer structure or more or a one-layer structure.

[0033]

As is clear from the above description, the reactor containment vessel of the present invention has the following effects. According to the means described in claim 1, since it is difficult to produce zinc hydroxide,
No blistering occurs between the layers of the organic zinc-rich coating film and the epoxy resin coating film. As a result, the anticorrosion coating is kept in a healthy state for a long period of time, so that the cycle for recoating the anticorrosion coating is prolonged, and as a result, the time and cost for repainting the anticorrosion coating are reduced. Become.

According to the second aspect of the present invention, since zinc hydroxide is not produced, the anticorrosion coating film does not swell.
As a result, the cycle for recoating the anticorrosion coating is lengthened, and the time and cost for recoating the anticorrosion coating are reduced. According to the means described in claim 3, the sacrificial anode is oxidized and the wall surface of the pressure suppression chamber is protected, so that the anticorrosion performance is improved.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a pressure suppression chamber showing a first embodiment of the present invention.

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 3 is a sectional view of a pressure suppression chamber showing a third embodiment of the present invention.

FIG. 4 is a view showing a temperature difference immersion test result and a salt spray test result of a corrosion-resistant coating film.

FIG. 5 is a diagram showing a schematic configuration of a boiling water reactor plant.

[Explanation of symbols]

1 is a reactor containment vessel, 3 is a dry well (container chamber), 4 is a pressure suppression chamber, 5 is a reactor pressure vessel, 7 is pool water, 15 is an anticorrosion coating film, 16 is an organic zinc rich coating film, Reference numeral 17 is an epoxy resin coating film, 18 is a corrosion-resistant coating film (thick film type epoxy resin coating film), and 19 is a sacrificial anode.

Claims (3)

[Claims] 1. A container accommodating chamber accommodating a reactor pressure container, a pressure suppressing chamber accommodating pool water, cooling and aggregating the steam as the steam is supplied from the container accommodating chamber, and this pressure. The anticorrosion coating film provided on the inner wall of the suppression chamber, the anticorrosion coating film is formed on the surface of the organic zinc-rich coating film and the organic zinc-rich coating film formed on the inner wall of the pressure suppression chamber. A reactor containment vessel comprising an epoxy resin coating film. 2. A container accommodating chamber accommodating a reactor pressure container, a pressure suppression chamber accommodating pool water and cooling and condensing the steam as the steam is supplied from the container accommodating chamber, An anticorrosion coating provided on the inner wall of the suppression chamber, wherein the anticorrosion coating is a thick film epoxy resin coating formed on the inner wall of the pressure suppression chamber. 3. The reactor containment vessel according to claim 2, wherein a sacrificial anode is provided on the inner wall of the pressure suppression chamber.