At the 27th Party Congress, Mikhail Gorbachev stressed the need for radical change. Complaining that the economy had been stagnating since the 1970s, he called for a restructuring (perestroika) of Soviet society. The party adopted his suggestion and called for greater openness (glasnost) in public dealings. Perestroika and glasnost thereafter became words frequently used in Soviet reforms.
The Chernobyl atomic power station exploded. Thirty-two people were killed at once; a fallout cloud drifted westward over Europe; parts of Belorussia and the Ukraine were permanently evacuated. On Oct. 2 the remaining Chernobyl atomic reactor was buried under a security mound of metal and concrete. Four years later, there was still a 30-mile exclusion zone around the site.
