[en] A calculation is given of the rate of deposition of particles from a nuclear aerosol due to the combined effect of diffusion and gravitational sedimentation, on the floor and ceiling of the containment vessel. For the floor, the result is found to be less than that given by the usual approach of adding the rates for each of the processes acting separately, the maximum difference being about 23%. For the ceiling, the result is less than that for diffusion alone, the difference increasing with particle size. (author)

[en] Inhalation is the first step towards respiratory tract intake of chemical and radioactive toxics. Particle deposition in human airways has been described by several authors as showing large individual variations. This study intends to contribute to assess this variability limits especially with reference to age. The method used is basically a measurement of retention, by difference between inhaled and exhaled air concentrations, of inert monodispersed aerosols, during controlled breathing. Particles of 1, 2, 3 μm MMAD (polystyrene latex) are measured in size and concentration by laser velocimetry. A Fleish pneumotachograph is used for controlling respiratory parameters. Healthy subjects, male and female, undergo the test at various tidal volumes, frequencies and flow rates, simulated resting and exercising ventilation; their respiratory function is also explored in a very complete way. 20 adults between 23 and 54 years have been tested in order to assess the laboratory reference values. 25 children, 8 under the age of 8 years, and 17 between 8 and 15 years, have been tested in a similar way. Compared to adults, children, especially under 8 years, have different total deposition mean values, higher for spontaneous and quiet controlled breathing, lower for exercising controlled breathing. Total deposition is dependent on particle size, higher for 2 than for 1 μm MMAD, but also, on lung volume, V.C., T.L.C., F.R.C., to which it is inversely proportional. 19 refs.; 4 tabs

[en] The patent describes a method of, and apparatus for, decontaminating garments and soft goods contaminated with radioactive particulate matter, chemical agents, toxins and/or biological agents. The garments are placed in a cleaning drum, and the drum is agitated during a wash cycle. A dry cleaning solvent is added to the drum during the wash cycle and then drained to a distillation apparatus. A neutralizing agent located in the distillation apparatus deactivates the biological and toxin contaminants, and chemically breaks down the chemical agents. The washing apparatus also contains a filtering system for continuous removal of particulate material suspended in the solvent during the wash cycle. (UK)

No abstract available

[en] Because some designers of aerosol transport systems use the assumption that aerosol penetration through a system is maximized of the flow Reynolds number is 2,800, we have conducted tests to determine if such an assumption is appropriate. Although we do not believe that optimal performance of an aerosol sample transport system can be presented solely in terms of the Reynolds number, we have presented our results in terms of that parameter to compare our work with the results of an earlier study. Two types of experiments were performed. First, the penetration of liquid aerosol particles through horizontal tubes was experimentally investigated for a range of design and operational conditions. For a particle size of 10 μm aerodynamic diameter, the maximum penetration through a 6.7 mm diameter tube was associated with a Reynolds number of approximately 2,000; the maximum penetration through a tube of 15.9 mm occurred at a Reynolds number of about 3,000; and the maximum penetration through a 26.7 mm diameter tube occurred at about 4,000. It was also experimentally demonstrated that for a fixed flow rate through a horizontal tube, there is an optimum tube diameter for which the aerosol penetration is a maximum. An early study dealing with aerosol particle penetration through a 16.8 mm inside diameter loop of tubing (two vertical tubes, two horizontal tubes and three 90 degrees bends) suggested there was a fixed Reynolds number for optimal aerosol penetration independent of particle size. Those experiments were repeated here and the agreement with those tests is excellent. 16 refs., 8 figs., 3 tabs

[en] To develop a model enabling the deposition during postnatal growth to be calculated as precisely as possible, we first prepared a calculation model for adults. The results obtained for aerosol depositions in a range of 0.08 μm to 10 μm aerosol particle diameter were compared with the experimental results reported by the GSF group in Frankfort, Fed. Rep. of Germany. The results showed good agreement, and we therefore used the same method to calculate the deposition for newborns and 10 years old children. To obtain the length, diameter and number of pathways we used the method described in the publications of Hofmann et al. The results may be summarized as follows: For aerodynamic particle diameters of 1 μm, both the total and local deposition for adults, 10 years old children and newborns agree; For aerodynamic diameters of 8 μm, newborns compared to adults showed a total deposition lower by about 10% (the pulmonary deposition is almost the same, and the tracheobronchial deposition is increased); For aerosol diameters of 8 μm, the total deposition found in 10 years old children is almost similar to that of adults (the tracheobronchial depositions agree, the pulmonary deposition is increased). 14 refs.; 7 figs

[en] An accident with atmospheric effluents at NPP leads to radioisotope transport into fool chain as a result of deposition of particles translocated with air on the territory vegetable products. The TARACAT program gives an opportunity to estimate radioisotope migration for agricultural and zootechnical productions in the case of a nuclear accident

[en] This paper discusses the experimental application of the Monin-Obukhov similarity theory in vertical wind profile simulation. There is a good reason to use this theory as the base theory in routine application wind models intended for e.g. radio-active and other pollutant dispersion control. The Monin-Obukhov similarity theory is based on organisation of variables into dimensionless groups by means of scaling variables that are generally determinable from the commonly available meteorological data. It is expected that proper choice of dimensionless groups allows determining of empirical relationships between these groups that are universal - namely, that work everywhere. The 'universality' of so called universal functions determined at the Kansas location was tested over the similar location at Molve in northern Croatia. The universality was proved under the unstable and neutral conditions. Because of the very emphasised local effects characteristic for the Molve's stable conditions, appropriate local similarity functions had to be designed for two locally specific stable categories. Detailed local stability classification was done by means of the Kazanski-Monin stability parameter μ. Local similarity functions were based on the same dimensional analysis as universal functions. As late as the local similarity functions (for unstable and neutral categories) the satisfying local wind speed profile model was created. In general, depending upon the locality, it could be necessary to add local similarity functions in the local wind model. It was shown that it was possible to design the local functions as practical for routine application as the universal similarity functions. (author)

[en] The Leak Path Factor (LPF) for a nonreactor nuclear facility is a critical component for the evaluation of the source term used to evaluate the on-site and off-site consequences when an accident produces aerosols containing radioactive powders that propagate through the facility and finally to the outside environment. The Leak Path Factor is defined as the fraction of the airborne radioactive particulate material that is in the respirable size range within the building that escapes via available pathways to the outside environment. This paper presents a methodology to evaluate the LPF for various accident conditions (e.g., seismic event, fire) that could take place in a nonreactor nuclear facility using MELCOR computer code. The methodology presented could enable analysts to efficiently model facilities to assess the magnitude of the LPF by evaluating its various components

No abstract available