Radioactivity airborne

Airborne radiation can appear in any room, enclosure, or operating area in which radioactive materials exist in concentrations in excess of the amounts specified in Table 1 of Appendix B to 10 CFR 20. Post a sign or signs bearing the radiation caution symbol and the word CAUTION in areas where exposure could occur. 

The analysis of natural radioactive materials is relatively straightforward, since it usually involves the determination of a small number of well-known radioisotopes of a few elements. The determination of manmade radionuclides in air samples is more complicated, because several radionuclides of a number of elements may be involved both qualitative and quantitative studies may be needed, and carriers may have to be identified. 

The final aim of qualitative analysis is the identification of all radionuclides present in sample. The procedure has two steps  

The aim of quantitative analysis is to measure an amount of radioactivity in either a relative or an absolute sense. Common units are the becquerel (Bq), becquerel per unit mass or becquerel per unit volume. In special cases, the activity is expressed as a mass of the radionuclide. 

From the standpoint of the pollution of cities and smaller industrial agglomeration, this involves the atmosphere above cities and conurbations up to a height of about 1500 m where essential changes with time may be observed in several days. Authorities of particular regions are competent to act in these cases. 

The pollution of large industrial agglomerations is related to wider regions up to levels of about 10 km. As regards concentration changes, times of several weeks are important and the regional authorities are responsible for action taken. 

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Respiratory protective equipment for use against airborne radioactivity... 

BS 5243 General principles for sampling airborne radioactive materials. 

EH53 Respiratory protective equipment against airborne radioactivity. 

Radon and its decay products were a major focus of meetings held in Capri, Italy, in 1983 and in Maastricht, the Netherlands, in 1985. These meetings reported on ongoing national surveys in European countries, on laboratory and field studies on the properties of radon decay products, and on the models for relating the airborne radioactivity concentrations to the human lung. 

Andrews, L.L., S.D. Schery, and M.H. Wilkening, An Electrostatic Precipitator for the Study of Airborne Radioactivity, Health Phvs. 46 801-808 (1984). 

The reduction in PAEC is considerably higher than can be accounted for by filtration directly (Jonassen, 1984a, Jonassen and McLaughlin, 1984), because the filtration as suggested, not only removes radioactive material, but also through removal of aerosol particles increases the unattached fractions and thus enhances the plate out- removal of airborne radioactivity. On the other hand the filtration-induced increase in unattached fractions will increase the average radiological dose per unit of PAEC and this is responsible... 

Sinclair, D., A.C. George, and E.O. Knutson, Application of Diffusion Batteries to Measurement of Submicron Radioactive Aerosols, in Airborne Radioactivity (D.T. Shaw, ed.) American Nuclear Society, La Grange Park, IL, pp. 103-114 (1978). 

Before addressing the question of the health impacts of radon and its decay products, the levels that have been found in indoor air will be reviewed. During the past decade, there has been an increasing number of surveys on the concentrations of airborne radioactivity in homes and other structures. A number of systematic national surveys have been conducted during the past five years so that there is substantial information available on radon concentrations in many European countries and Canada. A summary of these studies is presented in Table II. 

The principal health effect of airborne radioactivity is the induction... 

Cochran, J. A., Smith, D. G., Magno, P. J. and Shleien, B. (1970). Investigation of Airborne Radioactive Effluent from, cm Operating Nuclear Fuel Reprocessing Plant, Report No. BRH/NERHL-70-3 also Report No. PB-193803 (National Technical Information Service, Springfield, Virginia). 

The air concentrations of thorium and other airborne radioactivity near a former thorium and rare-earth extraction facility in the United States were measured. The maximum radioactivity due to all three isotopes of thorium at a site about 450 feet from the primary waste pile was 0.66 fCi/m. Although the background thorium radioactivity was not reported, the total radioactivity at a site about 4000 feet south of the waste pile was about 3.5 times lower than a site 450 feet from the pile (Jensen et al. 1984). 

Jensen L, Regan G, Goranson S, et al. 1984. Ambient monitoring of airborne radioactivity near a former thorium processing plant. Health Phys 46 1021-1033. 

Blok, J. (1958) Airborne radioactivity after a reactor accident. Proceedings 2nd International Conference on Peaceful Uses of Atomic Energy, 18, 325-8. Geneva, United Nations. 

Krzesniak, J.W. Porstendorfer, J. (1978) Diffusion coefficients of airborne radioactive iodine and methyl iodide. Health Physics, 35, 417-31. 

Step 10. Count the gamma rays emitted by the sample with a Ge detector plus spectrometer after the same time interval as in Procedure 8A. The airborne radioactivity sample should be counted as soon as possible after sample collection, with data recorded in Data Table 8.5 Repeat counting after selected intervals and record in Data Table 8.6, as indicated below. Determine the chemical yield as described in Procedure 8A, based on the information recorded in Data Table 8.4... 

Three different laboratories conduct an experiment to determine the amount of airborne radioactivity on BaS04. Laboratory A finds no activity B observes both alpha and beta activity that decay with a half life of several days C observes alpha and beta activity that increase with time. Explain their disparate findings. 

Very high radiation area Airborne radioactive area Labelling of containers... 

The utilization of gamma spectrometry for the quantitative determination of low level activity radionuclides in the natural environment is limited because the influence of the natural geochemical background is very strong, but the technique is often used in the study of airborne radioactivity [6, 7]. Low-level gamma spectrometry is used principally to determine the activity of nuclides such as Co, Cs, and Pb (Fig. 15.1). 

Eadie GG, Port CW, Beard ML. 1979. Ambient airborne radioactivity measurements in the vicinity of the jackpile open pit uranium mine New Mexico. Report ISS ORP/LV-79/2. NTIS PB292379. 

To reduce airborne radioactivity (e.g. Rn), the space between shielding and detector may be filled with paraffin. Cadmium and copper may be added to the shielding as neutron absorbers. Because (n, y) reactions in these materials give rise to a secondary y-ray background, the detector may be surrounded by mercury, which absorbs y rays very effectively and may be refined by distillation. 

Albrecht, E. and Kaul, Continuous registration of airborne radioactivity in nuclear operations. IAEA, Vienna, 1967. 

Millies-Labroix, J.-C., Bourlat, Y., Mosnier, R., Airborne radioactivity measurements in Montlhery (France), in Proc. Second Int. Meeting on Low-Level Air Radioactivity Monitoring, Madralin, near Warsaw, Poland. 14-18 Feb. 1994. 

Radiation monitoring equipment covers a variety of models designed for a specific purpose. In this section we shall briefly discuss measurement of airborne radioactivity. Radionuclides are released into the atmosphere from operating the various facilities. These radionuclides are dispersed to populated areas where exposure occurs by breathing or swallowing the materials. 

The most common form of monitoring for air contamination is by using samplers at a number of selected locations intended to be reasonably representative of the breathing zone of the workers. Usual sampling and measuring methods of airborne radioactivity are shown in Table 9.8. 

Sampling and measuring methods of airborne radioactive materials... 

One of the most impressive programmes of airborne radioactivity is the one implemented by the Environmental Measurement Laboratory (EML) in New York, USA. This started in January of 1963 as a continuation of a programme that was initiated by the U.S. Naval Research Laboratory (NRL) in 1957, and was continued by them until the end of 1962. 

A summary of airborne radioactivity measurements in Monthldry, France is presented in the report by Milles-Lacroix et al. (1994). Radioactive aerosols particles are collected in surface air, using cellulose filters and high output pumps (110 m%). Equipment operates on a permanent, 24-hour a day basis, and filters are replaced daily throughout the year. The volume of filtered air is 2600 m per day. After removal, individual filters are subjected to alpha counting, using a ZnS counter, and to beta... 

Jackson, W.M., Noakes, J.E. and Spaulding, J.D., Forage A sensitive indicator of airborne radioactivity. Health Phys., 40 (1981) 84-91. 

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