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Some aspects of $sup 212$Pb and $sup 232$Th airborne contamination in a monazite ore mill (in Portuguese)

Thesis/Dissertation ·
OSTI ID:4363986
ABS>Thesis. Sampling for measurements of airborne radioactivity is performed to assess the possible radiation hazards associated with the ore processing. Since the major contaminant (/sup 220/Rn) has a short half-life (54 s), the degree of radioactive contamination in the working atmosphere is determined through measurement of airborne /sup 212/Pb, which is the /sup 220/Rn decay product with the longest half-life (10.64 h). High volume air samplers (Staplex) and Whatman-41 filter paper are employed to collect airborne particles and the total alpha activity is determined for all samples by means of the ZnS(Ag) scintillator method. Long-lived activity on the filters is found to be due to finely divided monazite particles. Highest levels of /sup 212/Pb and monazite particles in the atmosphere are found in chemical and physical treatment areas of the plant, respectively. (INIS)
Research Organization:
Rio de Janeiro Univ. (Brazil). Instituto de Biofisica
NSA Number:
NSA-29-015364
OSTI ID:
4363986
Report Number(s):
INIS-mf--944
Country of Publication:
Brazil
Language:
Portuguese