[en] Irradiation of electrostatic dust filters with x-rays can be used as a means to study the charged stage of these filters. The method requires knowledge of the rate of ion production in the filter interstitial cavities. Bragg-Gray cavity theory is used to determine the relationship between ion production in the cavities and that in free air as measured by the exposure. It is further shown that due to the cavity size found in actual filter systems that the generalized theory of Burlin is required for the proper estimation of this correction factor which depends on photon energy and filter type. An experimental method is proposed to check the validity of the calculations based on cavity theory and the results of experimental tests reported. Reasonable agreement is found between theoretical predictions and experimental results and the need for use of an extended cavity theory clearly demonstrated. (author)

[en] This invention concerns a machine for removing surface coatings. It includes free plates, each plates, each one rotating about an axis itself having a circular rotation movement. The plates take up a radial orientation under the effect of centripetal force and strike the coating to be removed with their tips, whilst at the same time retracting under excessively sharp impacts. The machine is fitted with a hood inside which the pulverized coating is confined. A soft skirt fitted to the edge of the hood prevents the dust from being projected outside the hood by suction of the powdered coating. This machine is used in the nuclear industry for the decontamination of wall coatings without dispersion of radioactive dust into the atmosphere

[en] The study and development of an experimental high voltage generator specialized in the supply of electrostatic precipitators are presented. The main parameters of the pulse generator are: U = -30 kV, I = 8.8 A, τ = 120μs, f_r = 150 Hz. The pulse generator was tested on a laboratory electrostatic precipitator with nominal capacitance C = 25 nF, biased at -40 kV by means of a separate high voltage rectifier. The experimental results will be used for the creation of a more powerful pulse generator, a prototype for the supply of a real industrial electrostatic precipitator: U = -50 kV, I = 313 A, τ = 100μs, f_r = 300 Hz, C = 100 nF. (Author)

[en] Environmental sampling plays a significant role in nuclear safeguards. Isotopic ratio in uranium-bearing particles from swipe samples provides important information for detecting undeclared activities. Particle recovery which is the primary step of particle analysis, would affect the following analysis. The particle recovery efficiency of ultrasoneration recovery and vacuum suction-impact recovery were measured by alpha spectrometer with standard particles produced via aerosol spray pyrolysis method. The conditions of ultrasoneration were optimized and both recovery methods were evaluated. Finally, a procedure of particle recovery for unknown swipe samples was set up. (author)

[en] A short description of an NFP-Collector (Negatively Charged Fine-Particle Collector) proposed for the collection and removal of fine particles in dusty plasmas is presented. The effects of the Collector on silane plasma, in which dusty fine particles are formed, are presented

[en] Device for separation and recovery of a solid product carried by a gas utilizable mamely for radioactive particles recovery like plutonium oxide powder in a gaseous stream and composed of a filtrating porous material where the gas carrying the solid product is introduced to be separated from the solid

[en] Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

[en] The apparatus is made of an aspiration collector in the form of a gutter with many single elements which fit round the edge of an opening. Each element has a flexible tube that joints it to the evacuation duct

[en] For many years the classical techniques for filtration have been the subject of new developments, and the same applies to special purification techniques. These are generally the result of the association of known techniques or, more rarely, of completely new techniques which mostly utilze electrostatic effects. These new processes and equipment are reviewed especially in nuclear industry where these new techniques are studied and developed for public and worker protection

[en] Development of a dust removal system using static electricity has been conducted. It is envisioned that the system can collect and transport dust under vacuum. In the system, the dust is charged by dielectric polarization and floated by an electrostatic attraction force that is generated by the DC electric field. The dust is then transported by the electric curtain formed by the three-phase AC electric field. Experimental investigation has been conducted to examine the characteristics of the system. Current research results indicate that the dust removal system using static electricity can be used for fusion experimental reactors