Objectives:
The purpose of the article is to reveal practical technology of alternative reality formation in soviet society dased on the example Chornobyl catastrophe (1986) mythologization.

Material and methods:
During the research analyses and generalization of archive sources which were declassified by the Security Service of Ukraine have been performed. Also, analyses of scientific sources and documents, overview of soviet mass media related to the topic has been carried out.

Results:
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Conclusions:
All elements of alternative reality formation (mythologization), commonly used by KGB (Committee for State Security of the Soviet Union) namely truth secrecy; documents and material evidence destruction; intimidation; true information sources blocking; alternative “truth” formation; spreading such “truth” in mass media – all of them were implied in full. But the detection of the myth within historical time period came very quickly. Myth proved to be fragile – the occurrence of chemical reactions couldn’t be subordinated to the soviet power prescripts, they couldn’t be intimidated with KGB methods, however, the catastrophe consequences seemed too vivid for the full suppression. Main reason of failure in formation of soviet myth about harmlessness of radiation was international publicity.