Radon exposure in limestone cave.

Solomon, SB; Cooper, MB; O'Brien, RS; Wilkinson, L

Australian Radiat. Lab., Lower Plenty Rd., Yallambie, Victoria 3085, Australia

Conference: 5. Int. Symp. on the Natural Radiation Environment, Salzburg (Austria), 22-28 Sep 1991 .Editor Janssens, A; Lowder, W; Olast, M; Sinnaeve, J; Steinhaeusler, F (eds)

THE NATURAL RADIATION ENVIRONMENT., NUCLEAR TECHNOLOGY PUBLISHING, ASHFORD, KENT (UK), 1992, pp. 171-174, Radiation Protection Dosimetry [RADIAT. PROT. DOSIMET.], vol. 45, no. 1-4 suppl. ISSN 0144-8420 - NUCLEAR TECHNOLOGY PUBLISHING, ASHFORD, KENT (UK)

Detailed measurements of spatial and diurnal variation of radon and radon daughters were carried out in the Royal Cave, Bechan, Victoria, Australia, in order to assess the radiation exposure of the five full-time tour guides employed at the cave. The average value for potential alpha energy concentration, weighted for occupancy at locations through the cave, was determined to be 1.34 mu m.m super(-3) (64.3 mWL). From wire screen measurements the average unattached fraction was determined to be 13.8%, with a bimodal aerosol distribution with typical activity median diameter values of 1.1 nm and 170 nm for the lower and upper modes, respectively. Based on detailed workers records, the yearly average effective dose was assessed to be 1.7 mSv, with a range of from 0.08 to 2.8 mSv for the five tour guides.