JPS6296899A - Method of solidifying radioactive waste - 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 Industrial Application) The present invention relates to a method for treating radioactive waste discharged from a nuclear facility, and in particular to a method for treating radioactive waste discharged from the facility, as well as incineration of the facility, The present invention relates to solidification methods for radioactive solid waste such as radioactive powder and pellet waste from incineration facilities, air conditioning filters, heat insulating materials, used resins, metal pipes, and valves discharged from nuclear power plants.

(Conventional technology) Conventionally, radioactive waste liquid was solidified and stored in containers, but radioactive powder and granules from facility incineration, incinerator equipment, pelleted waste, and air conditioning waste discharged from nuclear power plants are used for air conditioning. Radioactive solid waste such as filters, heat insulators, used resin, metal pipes, and valves were stored in sealed containers.

(Problem to be Solved by the Invention) If radioactive solid waste is filled into a container and stored in a sealed state, the radioactive solid waste will be oxidized by the air present in the container and the container will be damaged. There was a risk that the container itself would oxidize, creating holes in the container and allowing radioactivity to leak out.

The present invention is intended to provide a method for disposing of radioactive waste that will not leak radioactivity even if it is dumped in the sea, especially considering the future dumping of radioactive solid waste into the sea.

(Means for Solving the Problems) The present invention involves filling a container with radioactive waste in advance, applying negative pressure to the container, and positioning the tip of the container so that the injected material directly reaches the bottom from the top of the container. This method of solidifying radioactive waste is characterized by injecting a solidifying agent into the container using a syringe.

(Function) When directly injecting solidification agent into a container filled with radioactive solid waste, an air vent is required. Not only will the solidification agent adhere to the air vent connection port, but it will also take time to inject the solidification agent. Although there is a problem of heating, by keeping the pressure negative, there is no need for an air vent and installation, and the injection of the solidifying agent can be done in a short time. Also, if the solidifying agent is sprayed from the top of the container and injected, since the contents are solid waste, the injected solidifying agent will collide with the solid waste and spread from side to side, sufficiently penetrating into the solid waste near the bottom. Without,
This is not a problem if there is solid waste that is not completely covered with the solidifying agent, but many voids will remain.
Although there is a possibility that the solidification progresses due to the air remaining in the voids, this drawback can be overcome by making it possible to inject the solidifying agent from the bottom upwards.

(Example) Hereinafter, a specific example of the present invention will be described with reference to FIGS. 1 to 3.
A case will be described in which a radioactive pellet product (hereinafter simply referred to as a product) from an incineration facility is solidified. 1st
The figure is a schematic flowchart, FIG. 2 is a diagram illustrating the structure of the drum, and FIG. 3 is a diagram explaining details of the syringe header of the drum.

The drum 1 to be filled with the product 2 is equipped with a syringe 3 in the center for injecting a solidifying agent (cement milk). The outlet end of this syringe 3 is set near the bottom of the drum 1, and its shape is shown in FIG.

The product 2 is filled into the drum 1 at a facility upstream of the assimilate injection position, and then carried in using the drum truck 4 and fixed at a predetermined location.

The injection header 5 (see Fig. 2) is inserted through the upper lid 60 of the drum 1 and the cap 7, and the syringe 3 is fixed to the inner shaft of the drum 1.
Connect with. The cap 7 of the drum 10 and the flange at the tip of the outer cylinder of the injection header 5 are pressed together via an adhesive gasket 14 (see FIG. 3) to maintain airtightness.

Next, after checking the opening/closing status of the vacuum valve 8, injection valve 9, etc.,
Start the vacuum pump 10. Suction until the pressure gauge 11 reaches the specified degree of vacuum (-560 llig) and then close the vacuum valve 8.
Close.

When injecting pelleted drum IK cement milk 12, cement and milk water are kneaded in a predetermined ratio in mixer 13 to produce cement milk 12.

The amount of cement milk 12 made is approximately 70 to 8 per batch.
0/, which is the minimum amount required to fill one drum 1 (2GC1j).

When injecting cement milk 12, when the injection valve 9 is opened and injection is started, the indicated value of the pressure gauge 11 is 1560 sa.
From Hg, it gradually begins to move towards zero (atmospheric pressure). After the movement of the indicated value of the pressure gauge 11 has stopped, the injection valve 9 is closed, thereby completing the injection process.

After the injection header 5 is removed from the drum 1 in which the solidifying agent 12 has been injected, the drum mouthpiece 7 is capped by a capping device and the drum 1 is transported to a temporary storage room.

After the cement milk 12 is injected, the cement milk 12 adhering to each device, piping, etc. is wiped off with a paper rag and, if necessary, washed with water to clean it. The cement milk 12 attached to each of these devices is a non-radioactive substance, and the injection header 5 hardly comes into contact with radioactive substances in the drum 1, so there is no particular problem in terms of radiation exposure when wiping with paper rags.

(Effects of the invention) (1) Easily inject a solidifying agent (cement milk, etc.),
A good solidified product can be obtained.

(2) Devices such as air vents are not required, and the purpose can be achieved with a simple and inexpensive solidification device.

[Brief explanation of drawings]

FIG. 1 is a schematic flowchart of an embodiment of the present invention, FIG. 2 is a structure of a drum (container), and FIG. 5 is a diagram illustrating details of a syringe header of the drum. Sub-Agents 1) Meifuku Agent Ryo Hara - Sub-Agent Atsushi Anzai Figure 2

Claims (1)

[Claims] After filling a container with radioactive waste in advance, the container is brought to negative pressure, and the solidifying agent is injected into the container using a syringe whose tip is positioned so that the injected material directly reaches the bottom from the top of the container. A distinctive method of solidifying radioactive waste.