Applied Physics Researches Division (APRD)

Project: ISTC A-1605

Posted on Apr 5, 2018

Project: ISTC  A-1605

Development of High-Efficient Filter Systems on the Basis of Super-Thin Basalt Fiber for Radioactive Aerosols Purification and Creation of a Work Circle for Filters Manufacturing with the Purpose of Their Operation at Nuclear Power Plants  ( ISTC  A-1605)

  1. At present, creation of highly effective energy- and resource- saving low-waste and safe technologies for cleaning of environment from radioactive emissions of nuclear-powered industrial enterprises, nuclear power plants and thermonuclear facilities presents undoubtedly an actual problem.
  2. Number of participants: 27
  3. Number of publications related to the Project: 10
  4. Number of conferences: 8 (Germany, Moscow, Kiev, Almaaty, Sevastopol, Sochi.
  5. Patent: АМ 20110016
  6. The Project implementation has allowed creating of highly efficient filtering system for cleaning radioactive aerosols at nuclear power plants.

For this purpose:

  1. A new method for obtaining of modified sorbents on the basis of super-thin basalt fiber with significantly enhanced sorption characteristics was offered.
  2. A pilot lot of new filters for cleaning of ventilation air from finely dispersed radioactive emissions was manufactured and installed in V2 ventilating system of the Armenian nuclear power plant. Their cleaning efficiency makes 98.4 to 99.6 %, which is comparable to efficiency of the IAEA standards for regular filtering blocks.
  3. A technological process of manufacturing filters from super-thin basalt fibers was developed.
  4. A technology of regeneration for the used filters after their withdrawal from service was developed.


  1. The offered filters, manufacture of which is based on local raw materials, are economic and two times cheaper than others used till now at the Armenian NPP.

It is intended to use, starting from the next 2014 year, the developed modified super-thin basalt fibers for air cleaning from radioactive isotopes in normal operation regime of Armenian NPP.


Success Story

At present, one of global environmental problems is creation of highly effective enterprises and devices for processing, recycling and burial places for wastes, life-support equipment. All of them demand new hybrid technologies, which, in turn, demand creation of new functional and constructional materials with rather specific properties. Therefore creation of highly effective energy- and resource-saving low-waste and safe technologies for cleaning of environment from radioactive emissions of nuclear-powered industrial enterprises, nuclear power plants and thermonuclear facilities presents undoubtedly an actual problem.

Under the financial auspices of the International scientific and technical centre, significant contribution is made in solution of this problem.

            Research of highly effective filtering systems of protection of the population and environment from radioactive emissions from the Armenian nuclear power plant, conducted in A.I. Alikhanian National scientific laboratory (former Yerevan Physical Institute) and in the Research Center For The Problem Of The Non Proliferation Of Mass Destruction Weapons, was supported within the framework of ISTC A-1605 Project financed by Canada. The Project activities were begun in January 2009 in close cooperation with foreign collaborators from AMEC NSS Limited, 700 University Avenue, Toronto, Ontario, Canada. The Project collaborators were recognized leaders in the field of filtering systems, and their participation guaranteed continuity of methodology and technical approach to the Project tasks.

            Super-thin basalt fibers (sized 1-3 microns in diameter) can be successfully applied in nuclear-power engineering to clean radioactive aerosols.

For preliminary research of filtering properties of various modifications of filtering materials, an experimental laboratory device was designed and installed in the controlled space. Now the experimental stand represents a complex, allowing investigating any sorbing materials, in particular, zeolites within a wide range of conditions.

            Physical and chemical regularities of basalt fibers were studied for the purpose of revealing optimum structure of aerosols of a wide spectrum at filtration through filtering materials.

An original technique of obtaining sorbent was developed on the basis of leaching superthin basalt fibers for the purpose of increasing sorption capacity of the sorbent. It uses a two-stage processing: hydrochloric acid and sulfuric acid leaching of super-thin basalt fibers.

Application of the new way of leaching has allowed redoubling of sorption characteristics of the filtering material in comparison with the earlier known leaching methods, which promotes an increase in the capture factor of radioactive aerosol particles.

The filtering material made using this method from the leached basalt fibers was fixed in standard filtering blocks of the ventilating system of Armenian nuclear power plant. Thanks to the increase in specific working surface of the offered filters reached by constructive modifications (the size of the filters was the same as that of Petrjanov filters), increase of the particle capture factor was provided.

Among other advantages of the developed filters it is necessary mention increased mechanical stability, resistance to chemical impacts (absence of formation of harmful combustible gases that takes place in Petrjanov filters used in NPPs, thermal stability (up to 750 оС in normal operation modes and even more at a short date), durability, moisture resistance. In the course of research within the framework of the Project, a technology of regeneration for the filters on the basis of super-thin basalt fibers was developed.


SEM image of basalt ultrafine fiber media and trapped particle


Two-Photon Fluorescence Laser Scanning Microscope image of  basalt ultrafine fiber media

The efficiency of experimental work on the project was provided by theoretical support of research groups of the Yerevan Physical Institute and Yerevan State University widely experienced in modeling of physical and chemical processes of solids. Here, original computatio

n procedure for resources of filters in the system of cleaning air (gas) from radioactive aerosols was developed. A method for determination of growth of pressure difference depending on time or weight of the particles accumulated on the filter surface was offered.

The offered filters, manufacture of which is based on local raw materials, are economic and  two times cheaper than others, used till now at the Armenian NPP. The manufactured blocks of new filters were installed in ventilating system V2 of the Armenian nuclear power plant. The obtained results have shown that the investigated filtering blocks operate stable; their cleaning efficiency makes from 98.4 to 99.6 %, which is comparable to efficiency of the IAEA standards for regular filtering blocks.

At present, the Project participants continue investigation of the influence of external factors on specific resistance as well theoretical research of mathematical models with the modified basalt fibers. In 2012 application of basalt filters for cleaning of air from radioactive aerosols in regular operating mode of Armenian NPP is supposed.


Project Summary

Armenian highland is one of classic regions of ancient volcano. Among the typical rocks, a prominent place occupies basalt. In 2003 some Armenian companies organized manufacture of ultrathin basalt fiber. Ultrathin basalt fiber has the following technical characteristics:

  • Average fiber diameter 2-3 microns;
  • Density 20-23 kg / m3;
  • Water content 2 %;
  • Temperature of application from -2600С to +7500С.

Basalt fibers are widely known and applied in construction, mechanical engineering, shipbuilding, electric-power industry. Ultrathin basalt fiber can be applied successfully in nuclear-power engineering to clean radioactive aerosols. At nuclear power plants in Russia and other CIS countries the greatest application find so called “FP” (Petryanov filters) filtering materials consisting of ultrathin disperse fibers of polymeric resins deposited on a fabric substrate. The Petryanov filters provide high efficiency of cleaning at rather low aerodynamic resistance.

Annually, 200 D-23L type packaged filters (with a volume of 0.5 cubic meters each) are used at nuclear stations, providing effective cleaning of air and reduction of the discharged activity up to permissible norms. Within recent years, permissible norms of NPP radioactive emission become more and more stringent, which causes to search for cheap filtering materials with high efficiency of cleaning. At normal NPP operation, when radioactive emission consists basically of aerosols with the particle size of 1-20 microns at low concentration (about 0.1-0.5 mg / m3), Petryanov filters function effectively enough. At nuclear power plants FP filters are changed annually. Their replacement is rather difficult and expensive operation. Besides, the problems of recycling of the used filters is not solved till now. They cannot be burnt because of emission of toxic substances. At their burial, the problem related to fire hazards, emission of toxic substances remain open; in addition, they occupy large volumes.

To catch aerosols at nuclear power stations, various methods and materials have been offered. At present, everywhere the techniques of thin cleaning of NPP ventilation air from radioactive finely dispersed are based on fiber filters. The use of ultrathin basalt fiber based filters at NPPs will result in the following advantages (in comparison with FP):

  • Higher temperature of application. Ultrathin basalt fiber can operate continuously at 7500С and intermittently up to 9000С;
  • Reliability at “heating-cooling” alternative actions. Basalt fibers maintain their performance and geometrical parameters at temperature cycling;
  • Low density and high thermal stability;
  • Chemical resistance;
  • Nonflammability, fire safety and explosion safety;
  • High environmental characteristics. Basalt fiber does not contain organic cancerogenic substance;
  • Longevity;
  • Resistance to fungi and mildew;
  • Resistance to ultraviolet and vibrations.


To protect the population and environment against the NPP radioactive emissions, it is planned to study the ultrathin basalt fibers efficiency, optimum parameters and develop, on the ground of the obtained data, effective (and at the same time less costly) systems of cleaning the radioactive aerosol air emission on the basis of these fibers. Besides, it is proposed to develop a process of manufacturing these filters, introduce them at the Armenian NPP and develop a technology of recycling the used filters after their withdrawal from service.        

Numerous works in this direction are known which were and are carried out in EU and other countries grounding their energy policy on operation of NPP and creating new reactor blocks. It seems appropriate to engage in the proposed Project some organizations having relevant experience in the designing and use of the population, personnel and environment protection from NPP radioactive emission.

The basic objective of the Project is the development of a highly efficient system of cleaning of NPP radioactive aerosols. To solve the stated problem, it is necessary to:

  • Study inertial, diffusion, sedimentation processes as well as engagement and screen effects for ultrathin basalt fiber using physical models;
  • Study the dependence of filtering coefficient upon the parameters of filtering systems;
  • Calculate optimum parameters of filtering systems as well as the airflow velocities at which the filter efficiency factor reaches its maximum;
  • Determine all technical characteristics of the filtering system and obtain needed licenses from relevant regulating bodies of the Republic Armenia;
  • Manufacture experimental samples of filters in an amount sufficient for installation in one of exhausting system of the Armenian NPP;
  • Install experimental filters in one of exhausting system of the Armenian NPP and provide the system designer’s technical supervision during one year;
  • Measure initial activity of aerosols, their concentrations after passage the system of cleaning, as well as the filter activity with captured aerosols by shielded low-background spectrometer devices;
  • Develop a process of manufacturing the filters from ultrathin basalt fiber;
  • Develop a technology of recycling the used filters after their withdrawal from service.

Taking into account considerable cheapness of manufacturing such systems (in comparison with Petryanov filters as well as other highly effective filters), it is possible to expect great demand for these systems.

The experience obtained at the Project implementation could be used by the countries grounding their energy policy on operation of NPP and creating new reactor blocks.

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