Category: Number 20
Publication: 20

Radioactivity of dust with alpha active radio nuclides (AAR), accumulated on the object "Ukryttya" premise 304/3 LFCM surface with area of about 1020 cm2, was measured during 09.2011 - 10.2012 years and time intervals from 1 to 288 days. A purifying of allocated surface was carried out between measurement intervals. Dust with AAR from contaminated air was sampled to two layer filters. Sampled dust amount increased with growth of dust accumulation time. Maximum growth rate was observed during period of LFCM drying out from condensate. Average dust radionuclide alpha activity rate generation was about 1,1?10-3 Bk/сm2?day or 3,9 kBk/m2?year (670 day accumulation data). It is necessary 2 mcm layer of selected LFCM surface transformation to dust to form year amount of AAR. Detected, that number of big dust particles exceeded number needed for lognormal distribution. Number of big dust particles decreased for about 1,7 times and number of small dust particles (less 0,8 mcm) increased for more than 2,4 times during 182 days. In bimodal lognormal distribution approximation median aerodynamic diameters (AD) for smaller particles were found. In studied time interval of dust accumulation value of median AD bigger fraction decreased and value of median AD smaller fraction was approximately constant.

Keywords: Radioactive dust generation; fuel aerosol; LFCM surface; LFCM destruction.

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