Evaluation of Beta Exposure in a Natural Uranium Processing Plant and the Beta Dose Attenuation of Various Shielding Materials

Analysis of the personnel monitoring reports of a natural uranium processing facility indicated significant beta exposure of the personnel. By carrying out beta dose measurements using thermoluminescence dosemeters (TLDs) operations with potential for beta exposure were identified and personnel dosimetry studies were conducted using finger/chest TLDs. Attenuation of the beta dose with distance in air and using some materials such as gloves, paper, Perspex, etc., were studied and the data are presented. The results are discussed in the context of the latest ICRP recommendations which suggest an additional annual limit of 0.5 Sv averaged over 1 cm2 at a nominal depth of 7 mg.cm-2 to prevent deterministic effects of the skin.