JPS6073396A - Sealing bellows - 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] [Field of Application of the Invention] The present invention provides a structure in which, when filling with water during fuel exchange, the bellows portion is brought into contact with the clear water after filtering floating matter such as crud in the water. This is what I did.

[Background of the invention]

The prior art will be explained below.

'a41 Figure u B W R, MARK II, fi
FIG. 2 is a vertical cross-sectional view showing the structure of a nuclear reactor scale 6'Jgfi and a pressure vessel.

The installation of the reactor pressure vessel 1 and the reactor containment vessel 2 is earthquake-resistant.
Considering thermal expansion during operation, the lower part is fixed to the reactor body foundation 5 and the foundation concrete mat 12 with foundation bolts (not shown), respectively, and the upper part and the surrounding area are left unrestrained, but during regular inspection. In order to perform water filling V for fuel exchange, a well seal bellows 10 is installed in the gap between the shield wall 11 and the reactor containment vessel 3, and a fuel exchange bellows 9 is installed in the gap between the reactor pressure vessel l and the reactor containment vessel 3. Each bellows is installed separately, taking into consideration the above-mentioned vibrations of each container during an earthquake, differences in thermal expansion due to temperature differences during operation, errors during site visits, etc. The bellows is made of thin stainless steel with multiple corrugations and has excellent heat resistance and rust prevention properties.

However, when exchanging fuel in the reactor pressure vessel during regular inspections, the spent fuel IC (not shown) and Tei-1 fuel are transported between fuel bollard racks (not shown), resulting in radiation exposure to the surrounding area. In order to reduce this, it is necessary to fill the above-mentioned transportation path with water for a shielding effect.

The water-filled state is shown in Fig. 2, and Fig. 3 is a detailed enlarged view of Fig. 2.

When the reactor is filled with water, deposits a to d on the surface and cracks inside the reactor pressure vessel become floating objects in the water during operation of the CUW system. After the regular inspection, the water is drained at trays 13 and 14, so floating objects adhere to the corrugated parts of the bellows, increasing the amount of radiation, and also having a negative effect on rust prevention. There were 1141 questions such as giving.

[Purpose of the invention]

In order to solve the above-mentioned problems, it is an object of the present invention to provide a cover made of (17) in which several strainers are attached to the cover at the time of fuel exchange in the entire upper gap of each bellows. The purpose is to prevent floating objects from accumulating on bellows corrugated objects.

[Summary of the invention]

The present invention is a 1:l type reactor containment vessel with a reactor well seal bellows. After being installed around the tank, it is filled with water for fuel exchange.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described as A when filled with water in Fig. 2.
The details of FIG. 4 will be explained.

FIG. 4 shows a state in which the reactor pressure vessel top rad 2 and the reactor containment vessel top head 4 are removed and filled with water to prevent exposure to radiation during fuel exchange.

The difference from the conventional groove structure shown in Fig. 3 is that each bellows 9. Covers 15 and 17 having a plurality of strainers 16 and 18 are completely installed around a portion of the upper space of IO to surround bellows chambers f and g. After that, filling with water prevents dust adhering to the cladding of the high line building from the reactor pressure vessel or the surface of each vessel from turning into floating matter in the water and flowing into each bellows chamber.

That is, water overflowing from the reactor pressure vessel when filled with water passes through a plurality of strainers provided on a cover provided all around the upper part of the bellows chamber and is sent into the bellows chamber.

Therefore, any floating matter in the water can be filtered out by the strainer, which prevents any floating matter from landing on the bellows.Also, when draining water, the water at the top of the bellows chamber can be drained from the drains 13 and 14 at the bottom of the bellows chamber. 17, it is possible to filter out the floating proboscis in the water.

After draining the water, strainers 16 and 18 can be taken out and easily decontaminated.

〔Effect of the invention〕

According to Kikori J, each bellows t/, ¥ construction, and fuel exchange can be carried out without changing the conventional work system of water filling and draining @hook, so even if the existing plastic plate/v is used, it is still possible to do so. There is an advantage that the disadvantages of the conventional method can be easily solved by simply attaching the cover temporarily during the preparation.

Also, it is possible to prevent the bellows from breaking due to foreign matter falling into the bellows chamber during the regular delivery period.

As shown in FIG. 5, a strainer is provided on a part of the cover and can be used in place of the strainer mentioned above.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view of the reactor containment vessel, Figure 2 is a diagram of the top head surrounding state shown in Figure 1 at the time of fuel exchange, Figure 3 is a partial view of the conventional structure in detail of part A in Figure 2, Figure 4 The drawings are a structural diagram showing a water-filled state in a detailed view of part A in FIG. 2 according to an embodiment of the present invention, and FIG. 5 is a structural diagram showing an application example of the present invention. 1...Reactor pressure vessel, 2...Reactor pressure vessel top head, 3...Reactor containment vessel, 4...Reactor containment vessel top head, Death...Reactor body foundation, 6...・・・
Thai aphram floor-17...Pool water, 8...
Bellows for bellows, 10
... Seal Well Bellows. Figure l Figure 2 Figure 3

Claims (1)

[Claims] ], Reactor Wealthy A of BWR type reactor containment vessel,
The haze and seal bellows for fuel exchange are characterized in that, at the time of fuel exchange, a cover with a strainer is installed around the entire circumference of the upper space of the bellows, and then water is filled f) for fuel exchange. Seal bellows.