A dose reconstruction of Co-60-contaminated window frames in a Taiwanese school

Since 1992, hundreds of buildings in Taiwan were discovered to have Co-60 c ontamination in the structural rebar, The contamination resulted from impro per handling of Co-60- contaminated scrap metal in 1982 and 1983, which sub sequently was recycled and used throughout Taiwan, Hsin-hsin Kindergarten s chool enrolled about 600 students over the 10-y period before the contamina tion was discovered. Hsin-hsin Kindergarten had three Co-60-contaminated st eel window Frames with measured dose rates on contact up to 150 mu Sv h(-1) . In this study, a range of potential doses received by the Hsin-hsin Kinde rgarten students were ISOSHLD dose modeling software, ISOSHLD is a rapid, i nexpensive screening tool to reconstruct dose ranges. To assess the potenti al risks to habitants of the school for the first year after construction, calculated dose rate ranges of 0.08 mu Sv h(-1) to 75.38 mu Sv h(-1) were t hen applied to the International Council on Radiation Protection 60 nominal detriment coefficients for stochastic effects. Risk estimates ranged from 1.46 x 10(-4) to 7.42 x 10(-4) excess fatal cancers per lifetime.