Dates of events relating to the Chernobyl nuclear accident:
April 26 - Explosion and fire in reactor No. 4 of Chernobyl nuclear power station, 1:23 a.m.
April 27 - Neighboring city of Pripyat, population 40,000, evacuated.
April 28 - Radioactive particles detected in Sweden; diplomats press Moscow for information. Following Politburo meeting, accident and unspecified damage confirmed in terse statement read on nightly TV news.
May 10 - Reactor fire extinguished after two weeks.
May 14 - President Mikhail Gorbachev addresses nation for first time about the “misfortune.” Says residents evacuated within hours, assails West for overstating accident’s seriousness and “defaming” Soviet Union.
July 27 - Six plant officials convicted of criminal negligence and other charges, sentenced to up to 10 years in jail. They are later released early and largely exonerated.