[en] For evaluating the risks in nuclear power plants accidental coincidence analysis is a wide-spread method. The paper describes this method on the basis of the so-called Birkhofer study conducted in the Federal Republic of Germany in 1977. The stages of the analysis are the following: determination of the events capable of bringing about radioactive emission, analysis of the chain of events and reliability, determination of radioactive emissions, study of the consequences of accidents and evaluation of risks. It is concluded that the risk of contamination accidents in nuclear power plants in comparison to other risks (illness, other accidents etc.) are negligible. (N.I.)