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.
- Research Organization:
- 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 Organization:
- none (US)
- OSTI ID:
- 839471
- Resource Relation:
- Conference: Americas Nuclear Energy Symposium (ANES 2004), Miami, FL (US), 10/03/2004--10/06/2004; Other Information: PBD: 3 Oct 2004
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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