The method of localization of surface radioactive contamination

 

(57) Abstract:

The invention relates to nuclear power and reprocessing industry, in particular to methods of localization of surface radioactive contamination during the construction and decommissioning of nuclear facilities in conditions where effective decontamination is difficult or impossible. Effect: simplified drawing of confining coatings in areas with high background radiation to eliminate manual labor and improve safety at work. The inventive method comprises applying to the soiled surface of the film-forming substance. This substance is lead in the foamed state attained by the introduction of film-forming solution of surface-active substances in concentrations that provide the necessary foaming. table 2.

The invention relates to nuclear power and reprocessing industry, in particular to methods of localization of surface radioactive contamination during the construction and decommissioning of nuclear facilities and dismantling of the equipment in conditions where effective decontamination is difficult or impossible.

One of the efficient methods of disposal facilities in place is filling the internal cavities of special concrete or other cementitious compositions. This option may be only for underground facilities and other heavily contaminated and cannot be decontaminated objects. Filling voids binder composition inevitably requires measures to reduce particulate emissions at the works. Radical means of preventing aerosol emissions is an effective decontamination, however, when the latter is difficult or impossible, it is necessary to resort to the localization of the surface contamination.

For localization of radioactive contamination on solid surfaces used numerous compositions based on organic and inorganic film-forming substances. Known compositions for the isolation of surface radioactive sagaidisanai resin. The compositions are applied on the protected surface by brush or conventional spray [2].

Similar features analog and the proposed method: the localization of the surface contamination carried out by applying to the surface of the protective film.

For reasons that impede the achievement of specified following technical result is that for application to exposed surfaces with a film-forming composition must be present in the premises of the staff that in case of high radiation fields or dangerous, or generally unacceptable.

The closest way to the same destination to the claimed invention on the totality of symptoms is the way the decontamination and containment of radioactive contamination by coating on the surface of the water-soluble polymers of the type of polyvinyl alcohol or latex [3], adopted for the prototype.

The reasons that impede the achievement of specified following technical result when using the known method, the same as the previous analogue, namely the use of manual labor when applying confining surfaces, the need for the presence of personnel in the contaminated areas, the complexity of the coating in hard to reach places.

The technical result in the implementation of the invention is that in the present method localization of surface radioactive contamination is carried out by filling processed premise foam containing film-forming substance in the natural destruction of which are formed on the surfaces of the guiding cover. To generate foam uses existing foam or penectomy introduced into the processing space through the existing openings (manholes, boxes, technological development and others). High mobility pins will provide access to all surfaces of the room. To ensure spanelement film-forming composition in the last injected surfactant corresponding class in concentration, providing the necessary foaming.

Conducted by the applicant's analysis of the prior art, including the search for patents and scientific and technical information sources and identify sources that contain information about the equivalents of the claimed invention, has allowed to establish that the applicant had not found the source, hare from the list of identified unique prototype as the most similar set of features analogue has allowed to establish the essential towards perceived by the applicant to the technical result of the distinctive features in the proposed method, set forth in the claims. Therefore, the claimed invention meets the condition of "novelty."

The results of the additional search known solutions in order to identify characteristics that match the distinctive features of the prototype of the characteristics of the claimed method, showed that the claimed invention not apparent to the expert in the obvious way from the prior art because the prior art defined by the applicant, not the influence provided the essential features of the claimed invention transformations to achieve a technical result.

The described invention is not based on the change of the quantitative characteristic (s), the submission of such evidence in the relationship, or change its appearance. Therefore, the claimed invention meets the condition of "inventive step".

The method is as follows.

Subject localization contaminated by radioactive substances premises using existing tools generate foam (progenerator type GWP-100 and others ) is filled through existing openings foam containing film-forming substance (e.g., foam-based aqueous solution, Sona on surfaces is formed of a continuous confining the floor, significantly reduces removable contamination.

Example 1. To determine the confining ability of the foam-based foaming solution composition: polyvinyl alcohol - 5%, sodium tripolyphosphate - 1%, the sulfonic acid - 1%, water is 93%, the glass with a capacity of 0.6 l at different heights vertically veiled three samples of stainless steel with a surface area of 10.2 cm2contaminated with mixed fission products (Cs-137, Ru-106, Sr-90) and pre-weighed. Then the glass using the foam generator was filled with foam with multiplicity equal to 60, and recorded the time of contact of the samples with foam as the natural destruction of the latter. The samples were dried in air, re-weighed, counted the thickness of the residual film and identified residual contamination by dry smear. The results are given in table. 1.

Example 2. To determine the effect of the multiplicity of foam on the efficiency of localization pollution repeated experience under the conditions specified in example 1, but with the multiplicity of foam equal to 160. The results are given in table. 2.

After repeated exposure samples with foam in a similar situation removable contamination was absent.

From the given data divinely alcohol, leads to a significant reduction of removable contamination. Increasing the time of contact of the surfaces with foam, reducing its multiplicity contributes to the formation of thicker films and, therefore, better containment of contaminants. Note that the radionuclides on the surfaces of the samples were in the form of nitrate salts, which is the worst from the point of view of efficiency of localization option as impurities soluble in water. In the case of low-solubility contaminants efficiency of localization will be higher.

The list of literary sources

1. Poluektova, B., Kovalchuk O. C., Kruglov, A. K. Removal of a nuclear power plant. / Nuclear technology abroad, 1990, 8, S. 3-8.

2. Simon A. D., Pikalov C. K. Decontamination. M: publishing house, 1994, S. 197-199.

3. Anpilogov N. I., Simanovsky Y. M., A. Trapeznikov, A. Decontamination in the nuclear power industry. M: Energoizdat, 1982, S. 145-146.

The method of localization of surface radioactive contamination, including drawing on the contaminated surface of the film-forming substance, wherein the film-forming substance result in a foamed state attained by the introduction of film-forming solution of surface-active substances is

 

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FIELD: nuclear power engineering.

SUBSTANCE: compaction involves cutting members into fragments using electroerosive destruction of member wall by pulse spark-arch discharges emerging between member and electrode. In addition, high-temperature treatment in oxidizing medium, in particular vapor formed, is carried out. Cutting and heat treatment are accomplished in water.

EFFECT: simplified procedure and increased safety.

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