[en] The invention concerns the selective measure, in continuous of radioactive particles in suspension in air which are able to reach respiratory system of man. 2 figs

[en] The process for measuring radon isotope concentration in a gaseous atmosphere, especially radon 222, radon 220 and radon 219, is characterized by collection and homogeneous repartition of solid daughter products in a sampling vessel containing a sample of the atmosphere and spectrometric determination of emitted γ radiation

[en] An aerodynamic calibration device, known as ICARE, has been set up in France at the Saclay Research Centre to certify instruments used to measure natural or artificial airborne radioactive particulate contamination or radon. ICARE can calibrate passive detectors and monitors with sampling air flow-rates of less than 60 m³/h. The adjustment of such parameters as ²²²Rn daughters volume activity, attached fraction and equilibrium factor, and the volume activity and size of α or β emitter carrying aerosols, allows realistic conditions to be obtained. ICARE complies with monitor test method standard currently under development by the International Electrotechnical Commission

[en] The most precise method to qualify an aerosol sampling system consists in measuring the deposition of particles on the filter or on the surfaces of which the system consists. It involves to be able to extract by washing the mass of particles deposited and to measure it. For this method, fluorescein salts (sodium or ammonium salts) are used; the concentration of the washing solution is measured with a photometer. According to the desired aerosol particles, an uranine generator for fine aerosols or a mono-dispersed aerosol generator is used. After the description of the design of the sampling head (intake, transfer and collection of aerosols on the filter), the tests realized to optimize the shape and the geometric dimensions are presented. The results obtained for 200 and 300 l.mn^-1 flow rates are given. To reduce the flow rate variations, a measuring and regulating system has been studied and tested. Finally, the reasons for which the sampling head depression has not been kept in spite of the improvement it brought are given

[en] The handling of products, including transuranic elements, in CEA (Commissariat a l'Energie Atomique, France) hot laboratories can give rise to incidental situations involving airborne contaminations. The follow-up and evaluation of the corresponding transfer pathways by contamination transfer experiments show that personal monitors are expected to give an alarm sooner than area monitors. This paper presents the design and performance of a prototype for air contamination personal monitoring. This appropriate monitor for transuranic elements is called MONICA α. Patented by CEA, it is under development now and soon, will be in production for use in corresponding facilities. 13 references, 4 figures, 3 tables

[en] The aim of the project is to adapt an existing radioactive aerosol calibration installation 'ICARE' at the Saclay Nuclear Research Centre (CEA), in order to provide precise activity concentrations of ²²²Rn and its short-life decay products that may be used to calibrate measuring instruments. ICARE is essentially a wind tunnel in which aerosols calibrated in size and labelled with ¹³⁷Cs or 2³⁹Pu are injected upstream of the test section. A new line of injection has been designed including three standard sources of ²²²Rn and a reference device for the activity concentration measurements of this gas. (R.P.) 8 refs., 6 figs

[en] The highly activated erosion dust produced by plasma-wall interactions is one of the main concern on safety of the future fusion reactor. The objective of this first ever experiment in a Tokamak is to characterize the airborne and deposited erosion dusts produces inside the JET vessel, after plasma shutdown and rise of pressure up to normal atmosphere through an HEPA filter. In this paper, we describe the sampling methodology and equipment, and give a summary of the main results from analyses of metallic and graphite samples: the production rates of erosion dusts non fixed on the wall, their resuspension ratio, the size distribution of aerosols, and the radioactivity of erosion products directly activated in the torus. (author). 4 refs.; 3 figs.; 2 tabs

[en] A high standard of protection against the harmful effects of radioactive aerosol dissemination requires a measurement, as representative as possible, of their concentration. This measurement depends on the techniques used for aerosol sampling and transfer to the detector, as well as on the location of the latter with respect to the potential sources. The aeraulic design of the apparatus is also an important factor. Once collected the aerosol particles often have to travel through a variably shaped duct to the measurement apparatus. This transport is responsible for losses due to the particles deposition on the walls, leading to a distortion on the concentration measurements and a change in the particle size distribution. To estimate and minimize measurement errors it is important to determine the optimal transport conditions when designing a duct; its diameter and material, the radius of curvature of the bends and the flow conditions must be defined in particular. This paper presents an experimental study in order to determine, for each deposition mechanism, the retained fraction, or the deposition velocity for different flow regimes. This study has pointed out that it exists a favourable flow regime for the particle transport through the sampling ducts (2 500 < Re < 5 000). It has been established, for any particle diameters, equations to predict the aerosol penetration in smooth-walled cylindrical metal ducts

[en] This presentation describes experiments to investigate the sorption of tritium on carbon dust of different particle sizes and specific surface areas. The conditions of exposure were determined at the first wall of the tokamak. These conditions include low tritium pressures and depending on the operation phase, temperatures varying between 25 degree C and 1000 degree C. The simulation of these conditions inside an exposure chamber was necessary in order to design and construct a specific exposure device that could be adapted to these unusual conditions. Initial sorption data were obtained for carbon dust derived from a JET first-wall tile. The amount of tritium sorbed into or onto the carbon dust is between 0.1 and 10 mg T per kg C for a 24 hour-exposure duration. It increases with dust temperature. Other determinations, dealing particularly on the influence of exposure duration, are required to interpret this initial data. 3 refs., 3 figs., 1 tab

[en] After the reasons for the existence of a individual monitor of the alpha atmospheric contamination, the design and the experiment of the sampler are presented. The monitor is aimed at informing the individual of an atmospheric contamination by alpha emitters, more particularly transuranium elements. The study aim at doing the dichotomic separation of aerosols and at eliminating the submicronic particles, taking into account the fact that the solid radon daughters can reduce the sensibility of the measurements. The sampler has been tested: captation efficiency, losses on the walls and distribution of the sampling on the filter; the experiment has been carried out for three membranes having pores fo which diameter is 3-5 and 8 μm