Additive Effective Dose Rates during Chemical Processing of Natural Minerals

Resumo

Occupational exposures to radiation during chemical treatment of black sand minerals (ilmenite, zircon, monazite, rutile) were evaluated. Additive effective dose rate (AEDR) is a new measure introduced to control the occupational exposure to radiation. The value of AEDR from the external γ-rays was estimated at 1.06 × 10^–9 Sv h^–1 kBq^–1. Based on the dose conversion coefficients obtained by the previous epidemiological studies, AEDR from radon and thoron gases was found to be 2.7 × 10^–9 and 1.52 × 10^–9 Sv h^–1 kBq^–1, respectively. The batch effective dose (BED) was suggested as a real alternative to the average effective doses over different locations. It is concluded that 1 kBq of a natural radioactive mineral adds an occupational effective dose of 9.52 × 10^–5 Sv year^–1.