JPS59102199A - Method of protecting release of residual radioactive material at cutting pipe or tank - 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 The present invention relates to a method for preventing the release of residual radioactive material during pipe or tank cutting.

When pipes and tanks containing radioactive materials are cut to remove them, there is a risk of contaminating the work area and exposing workers to radiation. Conventionally, when such contaminated pipes and tanks are cut, a local exhaust system or a vinyl cover has been used to prevent contamination of the work area and internal exposure of workers. However, these methods have drawbacks such as the inability to completely prevent the diffusion of radioactive substances, the poor workability, the long working time, and the high radiation exposure.

An object of the present invention is to provide a method that does not have these drawbacks, is easy to work with, can be applied to places with poor workability, and can completely prevent the release of radioactive substances.

As a result of intensive research, the inventor of the present application has discovered that after drilling a small diameter hole in the wall of a pipe or tank containing radioactive materials, a solution-based resin or electrostatic resin powder is sprayed through the hole to cover the entire inner surface of the pipe or tank. This objective was achieved by a method of preventing the release of residual radioactive material when pipes or tanks are cut, which consists of coating them with resin.

This resin coating method is easy to work with, so it can be applied to places where piping equipment is crowded and workability is poor, and since the inner surface is coated with resin during and after cutting the pipes and tanks, radioactive materials can be removed. release can be prevented by disaster victims.

The resin coating method may be either a spraying method in which a solution-based resin is sprayed or an electrostatic powder method in which a charged resin powder is applied. Insert the spout and apply resin coating to the inside of the piping or tank.

After the inner surface painting is completed, the entire inner surface of the piping or tank is coated with resin, so radioactive substances will not leak outside during cutting or removal.

This method is effective in preventing the release of radioactive materials, that is, preventing the spread of contamination, when piping containing radioactive materials is cut during remodeling and demolition of nuclear reactor facilities.

Resin has no air permeability, and even if foreign matter remains inside the pipe, it has high adhesion to the inner wall of the pipe, and furthermore, it has adhesive properties, so it can be completely sealed.

With this method, coating can be applied regardless of the angle at which the piping is installed, so once it is coated, it can be cut at any location, reducing the volume of waste. Furthermore, since the work is easy and slow, the exposure dose can be kept low even when working in high radiation dose areas, and the risk of internal exposure can be prevented as much as possible. In particular, large-diameter piping in the reactor cooling system is expected to be effective, simplifying safety measures during dismantling work and shortening work time.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the spray method and Figure 2 is an overview of the electrostatic powder coating method. In the figure, 1 is piping, 2 is a nozzle insertion hole,
3 is a resin container, 4 is a nozzle, and 5 is a charging device in the case of an electrostatic powder type. FIG. 3A is a longitudinal sectional view when the pipe is cut, and FIG. 3B is a cross-sectional view of the pipe. 1 indicates the piping, 2 indicates the coated resin layer, and 3 indicates the cutting location.

Claims (1)

[Claims] Piping that consists of drilling a small-diameter hole in the wall of a pipe or tank that contains radioactive materials, and then spraying solution-based resin or electrostatic resin powder through the hole to coat the inside of the pipe or the entire inside of the tank with resin. Or a method to prevent the release of residual radioactive materials during tank cutting.