Timeline of a disaster
Ukraine’s Minister of Power and Electrification Vitali Sklyarov tells Soviet Life magazine that the odds of a meltdown at Chernobyl’s nuclear power plant are “one in 10,000 years.”
April 25, 1986:
The plant’s operators prepare to conduct a special test to see how an emergency water cooling system would fare in the event of a complete loss of power.
April 26, 1986:
The test begins at 1:23.04 a.m.
Fifty-six seconds later, pressure builds in the reactor No. 4 in the form of steam. This causes an explosion that lifts a 1,000-ton lid that covers volatile fuel elements. Radiation is immediately released into the air.
As oxygen pours into the reactor, a graphite fire begins. A chemical reaction causes a second explosion and burning debris lands on the roof of reactor No. 3
Meanwhile, the engineer responsible for the night shift, Alexander Akinhov, does not yet think the reactor’s core is damaged. “The reactor is OK, we have no problems,” he says. Akinhov subsequently dies from radiation illness.
Thirty separate fires develop. An alarm goes off at a local fire station.
At 1.45 a.m. firefighters arrive. They know nothing about radiation and aren’t wearing any protective clothing. Driver Grigory Khmel later recalls: "We saw graphite lying everywhere. I kicked a bit of it. Another fireman picked up a piece and said 'hot.' Neither of us had any idea of radiation. My colleagues Kolya, Pravik and others all went up the ladder of the reactor. I never saw them again."
At 3:12 a.m. an alarm goes off at an army base deep in the Soviet Union. The general in charge decides to send troops. They arrive in Ukraine’s capital of Kiev at 2 p.m.
At 5 a.m. reactor No. 3 is shut down. Reactors No. 1 and 2 are stopped about 24 hours later.
April 27, 1986:
As more emergency response teams arrive, evacuations begin in a radius of 6 miles around the plant.
April 28, 1986:
The Soviet Union publicly admits for the first time that an accident happened but gives few details.
An alarm goes off at a Swedish nuclear plant after the soles of shoes worn by a nuclear safety engineer there test positive for radioactivity. The radiation is traced to Chernobyl.
May 1, 1986:
May Day parades to celebrate workers go ahead as planned in Kiev and Belarus’ capital Minsk despite huge amounts of radiation continuing to be released. Wind, and radioactive clouds, blow back toward Kiev after initially drifting northwest toward Europe. Authorities believe that by holding these celebrations they will prevent panic.
May 14, 1986:
Soviet leader Mikhail Gorbachev talks about the accident live on television. He subsequently mobilizes hundreds of thousands of people, including military reservists from all parts of the Soviet Union, to help in the cleanup.
They become known as "liquidators." Many will become ill and die from radiation-related diseases.
Gorbachev, in a 2006 memoir, says Chernobyl "was perhaps the real cause of the collapse of the Soviet Union."
Source: Nuclear Monitor Issue No. 724