Development of 85Kr atmospheric activity and comparison with prognosis

The results of monitoring of 85Kr volume activity in ground-level air of Prague over the period 1989-1995 are summarized. Seasonal dependence with a maximum in late spring and summer months and a gradual increase of 85Kr concentration in the atmosphere were observed. Linear approximation of long-term trend in the period 1983-1995 gives the growth rate of 35 mBq x m-3 per year. Exponential approximation provides an inter-year growth by 3.7%. The measured values were compared to the prognosis of 85Kr contamination development of the atmosphere from the early 1980s. They were found to be near to the low estimate of the assumed development. (author)