-
Cold War
In 1947, the Soviet-American Cold War began. By 1970, the Soviet Union was facing huge difficulties in military, energy and economic aspects. At the time, Soviet leader Gorbachev believed that funding large military-industrial enterprises could help the Soviet Union out of its economic difficulties. -
Construction begins
By the winter of 1970, in a small town in northern Ukraine, plans for a nuclear power plant began to be implemented. -
Period: to
Reactor 1
The first of the Chernobyl Nuclear Power Plants four reactors is ready to operate followed by number 2 in 1978. -
Pripyat
Pripyat was officially proclaimed as a city. -
Period: to
Error in Reactor #1
A partial core meltdown occurs in reactor No. 1. The extent of the accident was not made public until 1985. The reactor was repaired and put back into operation within months. -
Construction Unit 4 is completed
The plant becomes operational on the 20th. This news was reported by the media on 22 December, a festive day for workers in the energy industry. -
Period: to
Safe and Reliable
Vitali Sklyarov, Minister of Power and Electrification of Ukraine, in reference to the nuclear reactors in Ukraine, is quoted in Soviet Life magazine as saying: “The odds of a meltdown are one in 10,000 years. The plants have safe and reliable controls that are protected from any breakdown with three safety systems.” -
The test begins
-
01:23:44 – Explosion.
The 1000 ton lid above the fuel elements is lifted by the first explosion. The release of radiation starts. Air reaches the reactor and the oxygen results in a graphite fire. The metal of the fuel tubes reacts to the water. This is a chemical reaction which produces hydrogen, and this hydrogen explodes: the second explosion. Burning debris flies into the air and lands on the roof of Chernobyl Unit 3. -
Period: to
01:26:03 – fire alarm activated.
But no one was told about the radiation. -
Period: to
20:00 – A government committee is established
People of Pripyat gather on a railway bridge just outside of the city that provides a view of the nuclear power plant. They spoke of beautiful flames in all the colours of the rainbow (the burning graphite) and how the flames reached higher than the pillars of smoke. Sadly what they didn’t know, was that the wind that swept over them carried with it a dose of radiation equivalent to 500 Roentgen (exposure to 750 Roentgen/h, 7,5 Sv, is deemed a lethal dose). -
Evacuation of Pripyat begins.
Residents were given two hours to gather their belongings. The evacuation of Pripyat’s 43,000 residents took 3.5 hours, using 1,200 buses from Kiev. Everyone was in a hurry, but nobody was panicking. Of those who tried to return later, having realized that Pripyat was lost forever. -
Period: to
Deposits material to stop the reaction
Between 27 April and 1 May, about 1800 helicopter flights deposit over 5,000 metric tons of sand, lead, clay, and neutron absorbing boron onto the burning reactor. It is now known that virtually none of the neutron absorbers reached the core. -
The idea of the sarcophagus is born.
Over a hurried construction period of 206 days, crews erected a steel and cement sarcophagus to entomb the damaged reactor and contain any further release of radiation. -
Reactor 1 restarts
In September 29th, Reactor 1 restarts and is connected to the grid on October 1. -
Period: to
Construction work on reactors 5 & 6 is resumed.
-
Period: to
Reactor 2 restarts
-
A concrete roof (“sarcophagus”) is completed over the fourth reactor.
It is built to protect the environment from radiation for at least 30 years. 300,000 tons of concrete and 6,000 tons of metal constructions were utilised. -
Period: to
200 billion UK Pounds
The Chernobyl disaster has cost the Soviet Union the equivalent of 200 billion UK Pounds, a senior Moscow official discloses. -
Construction work on blocks 5 and 6 halted.
On May 23, 1989 it is decided not to complete the reactors. -
A fire breaks out in the turbine hall of Reactor 2.
The fire began in Turbine 4 while it was idle for repairs. A faulty switch caused a surge of current to the turbine, igniting insulating material on some electrical wiring.This subsequently led to a leak of hydrogen, used as a turbine coolant, into the turbine hall which created the conditions for fire to start in the roof and for one of the trusses supporting the roof to collapse. -
Disintegration of the Soviet Union
Post-Soviet States -
The Ukraine Government hold an international competition for proposals to replace the hastily constructed sarcophagus over reactor 4.
394 entries are received however only one proposes a sliding arch approach. A subsequent study confirms that by using this method there is much less chance of the construction workers receiving a harmful dose of radiation. -
Effects
Ukraine’s government declared in 1995 that 125,000 people had died from the effects of Chernobyl radiation. A 2005 report from the United Nations Chernobyl Forum estimated that while fewer than 50 people were killed in the months following the accident, up to 9,000 people could eventually die from excess cancer deaths linked to radiation exposure from Chernobyl. -
Reactor 3, the last functioning reactor, is shut down.
-
New Safe Confinement
The project contract for the New Safe Confinement (shelter over reactor 4) is finally signed, with French consortium Novarka constructing the 150 by 257 meter arched structure. Construction costs are estimated at 432 million euros with a project time of five years. -
The two halves of the New Safe Confinement are joined.
The two halves of the New Safe Confinement are brought together. Because of its enormous dimensions the arch was built in two sections. 1,000 bolts join the sections together. -
Completion of the New Safe Confinement
The New Safe Confinement (NSC), a multinational project to construct a modern radiation sarcophagus over the destroyed reactor 4 of the Chernobyl nuclear plant in Ukraine, has been effectively completed, the European Bank for Reconstruction and Development (EBRD) said on 25 April. The EBRD to date has provided €715 million of its own resources to support Chernobyl projects including the New Safe Confinement.