Improving the efficiency of fixed radionuclides’ removal by chemical decontamination of surfaces in situ
UDC: 621.039.75; 621.311.25
The article presents the results of work aimed at improving of chemical decontamination methods. A brief description of existing chemical decontamination technologies used to remove radioactive contamination (RC) from walls, floors and external surfaces of equipment without dismantling, i.e., in situ, is given. A vector of research aimed at improving the efficiency of fixed RC’s removal is also determined. The first aim of this work is to improve the decontaminating properties of removable polymer coatings used in practice. The following domestic products were chosen as study objects: compositions presented under trademarks VA, VL; and also special formulation ZPS-1M. Modifications of these compounds performed in SPSIT in some cases made it possible to significantly increase the decontamination factors (DF). The best results were obtained for VL compositions: it was found that due to certain additives it is possible to increase the DF for metal surfaces by a factor of 5–35 over the base product. Along with film-forming decontaminating compositions, an alternative patented technique has been developed in SPSIT. The main feature of this technique is usage of sorbent-based composite covering material previously saturated by decontaminating solution. New technique allows to achieve far higher decontamination factors (150–500) when fixed RC is removed from metal surfaces. In addition, it can be applied to polymer and other non-metal materials. One of the main advantages of given technique is a drastic (11–16 times) reduction of time required for carrying out decontamination operations. The obtained results may be useful for further research in this area. Thus, research performed allows to come up with general conclusion: there are possibilities to efficiently remove fixed RC from surfaces using rather simple chemical means. That, in its turn, could be a rational alternative to high-priced robotic decontaminating systems.
- Vasilenko V.A., Efimov A.A., Stepanov I.K. Radiation safety provision at objects with NPP. Saint-Petersburg, NIC Morinteh Publ., 2010,. 576 p. (in Russian).
- Koryakovskiy Yu.S., Doilnitsyn V.A., Akatov A.A. Decontamination: provision of radiation safety at enterprises of nuclear branch: tutorial. Saint-Petersburg. SPSIT Publ., 2010, 151 p. (in Russian).
- Ampelogova N.I., Simanovskij Yu.M., Trapeznikov A.A. Decontamination in nuclear power engineering industry. Moscow. Energoizdat Publ., 1982, 256 p. (in Russian).
- Lunner Sven-Jerik, Hegg Fredrik. Urea-containing agent for etching and the way of its production. Patent RF, no. 2259422, Int. cl. G23/F1/28, 2005, 15 p. (in Russian).
- Konkin E.D., Kizhnerova A.V., Kuleshova E.B. Technique of stainless steel decontamination. Patent RF, no. 2017244, Int. cl. G21F9/36, 1994, 7 p. (in Russian).
- Cuer Frederic; Castellani Romain. Decontamination Gel and Method for Decontaminating Surfaces by Wetting Using Said Gel: Pat. of WIPO WO2013092633, Int. cl. A61L2/232, A61L2/18, 2013, 70 p.
- Krickij V.G., Rodionov Yu.A., Stjazhkin P.S., Zelenina E.V. Activities aimed at dose rate decreasing in NPP premises belonging to 1&st circuit. Preprint. Saint-Petersburg. GI VNIPIET Publ., 2010, 187 p. (in Russian).
- Koryakovskiy Yu.S., Doilnitsyn V.A., Akatov A.A., Matveev S.A. Removable polymer coatings for decontamination: achievements and inventions, application, availability (review). Izvestija Sankt&Peterburgskogo gosudarstvennogo tehnologicheskogo instituta (tehnicheskogo universiteta). 2014, no. 25(51), pp. 68-79.
- TU 2316-219-56271024-2007. Protective polymeric structure of ZPS&1M3. Saint-Petersburg. Pigment Publ., 2007. Available at: http://www.pigment.ru/catalog/item/81 (accessed Feb 10, 2018) (in Russian).
- OST 95 10562-2001. Coverings polymeric protective for nuclear power plants. Part 1. The removed protective polymeric coverings. General requirements, application and choice. Moscow. VNIIPO Publ., 2002, 32 p. (in Russian).
- GOST R 50773-95. Coverings polymeric protective for improvement of a radiation situation. Methods of determination of coefficient of deactivation and time of protective action. Moscow. Gosstandart Rossii Publ., 1995, 20 p. (in Russian).
- Koryakovskiy Yu.S., Akatov A.A., Matveev S.A. Modification of removable polymer coatings for decontamination. Proc. of the II Sci.-Techn. Conf. of Young Scientists «Nedelja nauki-2012». Saint-Petersburg, SPSIT, 2012, p. 141 (in Russian).
- Koryakovskiy Yu.S., Akatov A.A., Maksimova U.M., Doilnitsyn V.A., Matveev S.A. Development of new removable polymer coatings for decontamination. Proc. of the Sci.- Pract. Conf. devoted to the 184th anniversary of formation of Saint-Petersburg State Institute of Technology. Saint-Petersburg. SPSIT Publ., 2012, p. 189 (in Russian).
- Koryakovskiy Yu.S., Akatov A.A., Doilnitsyn V.A. Decontamination by film&forming compositions: advantages and limitations, possibilities for usage during decommissioning. Proc. of the IX Int. Nucl. Forum «Bezopasnost’ jadernyh tehnologij: avarijnaja gotovnost’ i reagirovanie». Saint-Petersburg, NOU DPO «CIPK Rosatoma» Publ., 2014, pp. 232-235 (in Russian).
- Koryakovskiy Yu.S., Doilnitsyn V.A., Akatov A.A. Usage of improved film&forming polymer compositions for enhancement of efficiency of metals’ decontamination. Proc. of the Sci.-Pract. Conf. «Aktual’nye voprosy yaderno-khimicheskih tehnologij i ekologicheskoj bezopasnosti». Sevastopol. SevGU Publ., 2016, pp. 142-145 (in Russian).
- Stepanov I.K., Konstantinov E.A., Simanovskij Yu.M. Normalization of radiation situation in the process of post&accident recovery on site of Chernobyl NPP. Book 4. Sosnovyj Bor. Leningrad NPP Publ., 2006, 208 p. (in Russian).
- Koryakovskiy Yu.S., Doilnitsyn V.A., Akatov A.A., Shmakov L.V. Decontamination technique for metal and non&metal surfaces, contaminated by radionuclides. Patent RF, no. 2586967, Int. cl. G23F1/28, 2016, 18 p. (in Russian).
- OSPORB-99⁄2010. Basic health regulations of ensuring radiation safety: sanitary standards and rules of the joint venture 126.96.36.19912-10. Ekaterinburg. UralYurIzdat Publ., 2014, 108 p. (in Russian).