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Title: RADIOACTIVITY DOSAGE OF ORNAMENTAL GRANITIC ROCKS BASED ON CHEMICAL, MINERALOGICAL AND LITHOLOGICAL DATA

One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite and zircon. Chemical analysis revealed concentrations of uranium of {le} 30ppm, and thorium {le} 130ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for floor tiles in a standard room for samples with total concentration of uranium and thorium greater than 60ppm. On the basis of calculations of {sup 232}Th, {sup 40}K and {sup 226}Ra from Th, K and U analysis, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.
Authors:
; ;
Publication Date:
OSTI Identifier:
839471
Resource Type:
Conference
Resource Relation:
Conference: Americas Nuclear Energy Symposium (ANES 2004), Miami, FL (US), 10/03/2004--10/06/2004; Other Information: PBD: 3 Oct 2004
Research Org:
Centro de Desenvolvimento da Tecnologia Nuclear CDTN/CNEN/MG Caixa Postal 941-Campus da UFMG-Pampulha 30161-970, Belo Horizonte, MG. (BR); Departamento de Geologia da Universidade Federal de Ouro Preto 35400-000 Ouro Preto, MG (BR)
Sponsoring Org:
none (US)
Country of Publication:
United States
Language:
English
Subject:
29 ENERGY PLANNING, POLICY AND ECONOMY; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 58 GEOSCIENCES; ALLANITE; AUTORADIOGRAPHY; CHEMICAL ANALYSIS; ELECTRON PROBES; FLUORESCENCE; GRANITES; GRAVIMETRY; LITHOTYPES; MICROANALYSIS; NEUTRONS; NUCLEAR ENERGY; OPTICAL MICROSCOPY; RADIOACTIVITY; RARE EARTHS; SPECTROSCOPY; THORIUM; URANIUM; ZIRCON DOSIMETRY; ORNAMENTAL GRANITE; AUTORADIOGRAPHY