Situation after the accident
Nuclear accidents - Kyshtym (USSR)

The mixture of radioactive products released during the explosion contained mainly relatively short-lived radionuclides, such as ¹⁴⁴Ce, ¹⁴⁴Pr, ⁹⁵Zr, ⁹⁵Nb.

However, the greatest radiological hazard long after the accident is represented by long-lived ⁹⁰Sr (2.7% of the initial total activity), on a par with its descendant ⁹⁰Y. The half-life of ⁹⁰Sr (T_1/2 = 28 years) is much greater than that of ⁹⁰Y (T_1/2 = 64 hours) and, as a result, the total activity of ⁹⁰Sr and ⁹⁰Y, when a dynamic equilibrium is established, is equal to twice the activity of ⁹⁰Sr, i.e. 5.4% of the activity of the mixture at the time of release.

The...