JPS586497A - Method of processing equipment contaminated with radioactive material - 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 disposing equipment contaminated with radioactive substances, and provides a method that can render harmless clothing and other equipment worn by workers in nuclear power plants and the like, and allow them to be used repeatedly. This is what I am trying to do. The effective use of nuclear power has recently been widely studied and studied around the world, and it is well known that nuclear power generation is becoming increasingly popular.

By the way, it is natural for employees working at such nuclear facilities to wear clothing and other equipment to prevent damage from radiation and other substances, but such equipment may contain radioactive materials that are resistant to adhesion. If the clothing is stolen, the clothing, etc., will have to be disposed of. In other words, in the past, there was no suitable method to detoxify contaminated equipment, so equipment that was contaminated or potentially contaminated had to be discarded. Not only does the cost of such devices become extremely expensive, but the cost of disposing of them also increases.

The present invention was devised after repeated studies in view of the above-mentioned circumstances, and includes additives for buffering the corrosive effects of common salt, such as ferric ammonium sulfate, and soda carbonate, on orthotics. It is proposed that the equipment such as clothing be placed in the solution used for treatment, and the equipment should be boiled in a steel container for at least 5 minutes, or the equipment should be immersed and heated to around 40°C. After soaking and softening for 3 hours, it is taken out and washed with water, then washed with a detergent, washed with water, and dried.

The above-mentioned common salt is added in an amount of 50 to 60 parts by weight per 100 parts by weight of treated water.
By adding and dissolving K in parts by weight, a concentrated saturated saline solution is obtained, to which 30 to 40 parts by weight of ferrous ammonium sulfate [ferrous ammonium sulfate: (NH4)I
Fll (804)* - ferric ammonium sulfate:
(NH, entering SQ, Fe.

(so4)m] is added and dissolved. This ferrous ammonium sulfate, along with the above-mentioned common salt, forms the main body of the radioactive substance removal treatment in the present invention, and the fact that this ferrous ammonium sulfate is heated in the presence of the above-mentioned concentrated saline solution makes it more resistant to adhesion to clothing. It was confirmed that radioactive substances can be effectively absorbed and eliminated. That is, the radiation includes neutron beams, gamma rays, and proton beams.

There are X-rays, etc., and this BA is used for these radioactive materials.
It is difficult to clarify the details of how K works specifically, but in any case, it is known that iron or the radiation layer is used as an absorbing material, and this iron-based solution is A preferable absorption and quenching effect can be obtained by using the above-mentioned ferrous ammonium sulfate as a forming material.
It is also recognized that table salt has a similar trap-eliminating effect. According to the results of specific studies conducted by the present inventors, it appears that common salt has an excellent erasing effect on 1#- for the above-mentioned neutron rays, and ferric ammonium sulfate for comma rays. It has been confirmed that a dissolving solution of Furthermore, clothing contaminated with this kind of radioactive material is legally required to be stored for 150 days, and by storing it this way, some parts of the clothing may become contaminated to a high concentration of several hundred becocuries. Although the radioactivity of clothing has gradually decreased to below 10 Bq, for example, all clothing has become contaminated during the storage period, and the fibers that make up clothing have become contaminated. It is expected that it will be difficult to absorb or eliminate the radioactive substances that have penetrated into the tissues, but in the present invention, the high concentration It is presumed that the salt used as a conditioner corrodes the fibrous tissue appropriately, and that the iron-based solution containing iron ammonium sulfate also effectively penetrates into the tissue, exerting its respective elimination or absorption effects. Regarding the temperature conditions, a certain absorption and elimination effect can be obtained even at room temperature, but it takes at least several days or more to bring it to a harmless level of seawater level (below 1 becocury), so appropriate heating is required. It is preferable to do so. For example, by boiling, it can be made harmless for about 10 minutes or less, but by boiling in the above-mentioned highly concentrated saline solution, even in the presence of dissolved soda carbonate, etc., the fibers of clothing etc. can be considerably eroded and altered. Even if the acid radical radioactivity can be eliminated or absorbed, the durability will rapidly decrease. Therefore, it is preferable to heat to about 40° C. from the viewpoint of durability of clothes, etc. Even at this temperature of about 40° C., a harmless state can be formed in about 3 hours. It should be noted that there are cases where it is not necessarily desirable to treat for around 3 hours in this way, and specifically, considering the relationship between durability and treatment time as described above, or the degree of contamination of equipment such as clothing. The temperature conditions will be determined. Sodium carbonate buffers the erosion or alteration of clothing fibers caused by concentrated common salt, and its concentration is appropriately selected in consideration of the above-mentioned salt concentration and temperature conditions. Generally, it is 1011/1 or more, but as mentioned above, in the case of relatively low temperature such as around 40℃, it is 31/1 or more.
It may be around 1/1.

After the treatment, it is thoroughly washed with water to remove the adhering components of the treatment agent as described above. In addition, since the above-mentioned treatment itself does not necessarily remove general stains caused by oil and other substances, after the above-mentioned water washing, normal washing with a commercially available detergent is performed, and then further water washing is performed to remove the detergent, and then water is wrung out. It is dried and made into a treated orthosis. When washing as described above, it is preferable to limit the use of bleaching agents as much as possible; that is, using a detergent containing a large amount of bleaching agents tends to weaken the fibers of clothing.

Specific embodiments according to the present invention will be described below.

Example 1゜In an iron container with a lid, water 51, salt 2.5#, and sulfuric acid 2
Iron ammonium 1.5 Jt9 and soda carbonate 80.9
Into the dissolved material, work clothes measured as having 5 to 6 ounces of radioactive material attached (stored in a steel container for 150 days after contamination as mentioned above) are charged, and the material is placed in the charging port. Closed with an iron lid and heated, about 100
The mixture was boiled at ℃ for 10 minutes.

After this treatment, the work clothes taken out of the container were washed with water, washed with a commercially available soap detergent, and then washed with water and dehydrated to dry.

After performing these series of treatments, we measured the adhesion resistance of radioactive materials to the work clothes, and the measuring device produced the same detection sound as in seawater, that is, it was estimated to be less than 1 becocury, and it was found that the radioactive material was not radioactive. I learned that the substance was being effectively removed.

Example 2゜ Water in the same iron container as in Example IK.

The same amounts of common salt and ferric ammonium sulfate as in Example 1 were charged, and 50 I of sodium carbonate was added to dissolve each of them.The work clothes stored after contamination in the same manner as in Example 1 were then charged. The mixture was heated to around 40°C and treated for about 3 hours while being slowly stirred.

After this treatment, washing with water, washing with detergent, and subsequent washing with water and drying were performed using the same I/C91 as in Example 1.

That is, as a result of measuring the thus obtained treated work clothes, it was confirmed that the treated work clothes were in a harmless state of less than 1 pekokyu.

In the case of the present invention as explained above, there is no suitable disposal method in the prior art, and the product must be disposed of, which in itself inevitably increases the cost considerably, and the cost for the disposal process is also considerable. This invention is industrially highly effective because it effectively removes and absorbs equipment that is contaminated with radioactive substances and enables its repeated use.

Representative patent attorney Shirokawa ---

Claims (1)

[Claims] A method for treating equipment contaminated with radioactive materials, which comprises immersing equipment contaminated with radioactive materials in a solution containing Minato-Atsushi solution of common salt, ammonium ferrous sulfate, and soda carbonate, and heating the equipment appropriately.