JP2000155194A - Radioactive contamination prevention method of reactor pool or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent radioactive contamination for the floor face and the wall face of a pool during water filling by laying a poly sheet having adhesion on the floor face and the wall face of the pool to mutually overlap the end edge parts of the adjacent poly sheets. SOLUTION: Radioactive contamination prevention during water filling of a pool such as a reactor cavity for nuclear fuel exchange or the like in a nuclear power plant is executed by using a poly sheet 3 having adhesion. The end edge parts of the adjacent poly sheets 3 are mutually overlapped to form an overlapping part 4 and contamination water is prevented from infiltrating through the peripheral side of the poly sheet 3. After the wall face and the floor face of the pool such as the reactor cavity are adhered and covered by the poly sheet 3, water is filled and the nuclear fuel exchange or the like is performed. After exchange working is completed, water is drained, and the poly sheet 3 stretched on the wall face and the floor face is removed to be scrapped. Since an amount of water permeability is small from the poly sheet 3 to the stainless face of the pool, after water drainage, decontamination working by pure water can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention fills a pool such as a reactor cavity and a reactor well for nuclear fuel exchange in a nuclear power plant. During this period, radioactive contamination on the floor and wall surfaces of the pool is performed. It concerns prevention methods.

[0002]

2. Description of the Related Art In order to prevent radioactive contamination of a pool such as a reactor cavity and a reactor well during flooding, it has been conventionally practiced to coat floors and walls with a policy. However, in this method, as shown in FIG. 2, a weakly adherent policyt 1 is laid on the floor and wall surfaces of the pool, and the periphery of the policyt 1 is tightly closed with a narrow tape of strong adhesive policyt. The sticking prevents radioactive contamination on the floor and wall surfaces of the pool during the water filling period.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent radioactive contamination on the floor and wall surfaces of a pool such as a reactor cavity and a reactor well during filling of a pool.

It is an object of the present invention to provide a method for preventing contamination which is easier to work than a method in which a narrow tape having strong adhesiveness is adhered to the periphery of the policyt having weak adhesiveness without any gap.

[0005]

Means for Solving the Problems An adhesive policyt is covered on the floor surface and wall surface of the pool by laying the edges of adjacent policyts on top of each other, so that the pool during the water filling period is covered. It is characterized by preventing radioactive contamination of floors and walls.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 3 denotes an adhesive policyt which is laid on a stainless steel surface such as a reactor cavity. The edge portions of the adjacent politics 3 are overlapped with each other to form an overlapping portion 4 so that contaminated water does not enter the politics from the periphery of the politics.

[0007] After covering the wall surface and floor surface of the pool such as the reactor cavity with an adhesive politics, water is filled, and the nuclear fuel is exchanged. , Which removes and discards the policy attached to the wall and floor, prevents the stainless steel surface of the pool from coming into contact with water during the water filling period, and eliminates decontamination work with clean water after draining. It was done.

[0008] When laying on the stainless steel surface of the pool, the adhesive politics adheres well to the stainless steel surface constituting the wall or floor due to the adhesive force, and air flows between the poliste and the stainless steel when the politics are laid. Very low uptake compared to other non-sticky politics. This is advantageous for laying politics in pools with high water pressure.

[0009] A comparative experiment was conducted on the installation of a policyt having tackiness and a policyt having no tackiness, and the amount of high-pressure water permeated between the policyt and the stainless steel in the pool was investigated. The result that the amount of penetration was very small in the policyt was obtained. If the amount of air taken in during the installation is large, the amount of high-pressure pool water that has penetrated between the policyt and stainless steel will increase, causing peeling of the installed policyt and radioactive contamination at the policymet installation site. However, this problem does not occur because the adhesive policy closely contacts the stainless steel constituting the wall and the like.

Further, since the peripheral edges of the tape having a strong adhesive force are superposed on each other and laid, the laying operation can be completed by an extremely simple operation.

[0011]

(1) A radioactive contamination prevention policy is laid in the reactor cavity, water is filled in the cavity, fuel rod replacement and the like are performed, then water is drained, and the policy is removed. As a result, the radioactive contamination level before the installation of the policyt and the radioactive contamination level after the removal of the policyt performed after draining the reactor cavity were almost the same level, and did not increase at all. That is, the effect of preventing contamination was outstanding. (2) Although a large amount of water is used in the conventional method of removing radioactive contamination after draining the pool, a large amount of water is not used in the method of laying the policyt according to the present invention. No need to treat water. (3) Compared with the conventional method, the method according to the present invention can simply perform the decontamination work in a short time and with a small number of people since the edges of the adhesive policy can be simply laid on each other. And so on.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method of laying a policyt according to the present invention.

FIG. 2 is a diagram showing a known policy laying method.

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1 weakly tacky policyt 2 strongly sticky policyt 3 sticky policyt 4 Overlapping part

Claims (1)

[Claims] 1. A pool (3) having an adhesive property is covered on the floor surface and the wall surface of a pool by laying the edges of adjacent policyts on top of each other, and the floor of the pool during a water filling period. A method for preventing radioactive contamination of a reactor pool or the like, characterized by preventing radioactive contamination of surfaces and walls.