抄録
The purpose of this study is to improve a quick method for estimation of 131I concentrations in the air using data measured by monitoring posts in case that a nuclear disaster occurs. In this method, 131I concentrations were estimated by multiplying 131I count rates of cloud-shine measured with Na(Tl) detector by concentration conversion factor. A previous study suggested that it was difficult to determine passing-through time of plume from temporal change of 131I count rates or dose rate. Our study applies the method for estimating passing-through time of plume from temporal change of noble gas counts. The 131I concentrations in the air at Oarai center, Japan Atomic Energy Agency resulting from the accident at the Fukushima Daiichi Nuclear Power Station were estimated by proposal technique. The result of comparison of this method with sampling method for 131I concentrations in the air were within factor 3.
