Abstract
The exposure rates of γ-rays from 41Ar clouds issuing from the stack of a nuclear reactor were calculated on the basis of Pasquill's cloud diffusion formula, using exact γ-ray attenuation and build-up formulas. The results have agreed well with the experimental values of a 41Ar release test performed in 1961 at the Tokai Research Establishment, Japan Atomic Energy Research Institute.
The cumulative dose of γ-rays received at a given point from shifting 41Ar cloud for a long period was also calculated by considerations based on the probability concept. The validity of the method has been confirmed by comparison between the value estimated with statistics of meteorological data and the cumulative value of observed γ-exposure. By this method, the maximum allowable release rate was obtained for the Tokai area.
