RADIOACTIVITY CHERNOBYL, Slavutych town. Ukraine. 20th Anniversary memorial, by family, friends, comrades after midnight for the 28 firemen who died of ionizing radiactive contamination, after trying to put out the fire in reactor 4 at Chernobyl power station in 1986. The fire started in the early hours of the 26th April 1986, The radioactive cloud dispersed worldwide. 250 thousand were evacuated. Exclusion zones exist in close vicinity of Chernobyl in Ukraine and Belarus where people will not be able to live for tens of thousands of years.