The disaster took place on April 26, 1986 at 1.23 a.m in the No. 4 light water graphite moderated reactor
The Chernobyl disaster remains one of the two level 7 incident on the international Nuclear Event Scale (INES) making it the biggest manmade disaster of all time.
Radioactive isotopes, such as caesium-137, iodine-131 and strontium-90, were released into the air.
Belarus received 70% of the fallout from Chernobyl, which contaminated one fifth of the country’s land used for agriculture.
In terms of surface area, Belarus and Austria were most affected by higher levels of contamination However, other countries were seriously affected; for example, more than 5% of Ukraine, Finland and Sweden were contaminated to high levels. More than 80% of Moldova, the European part of Turkey, Slovenia, Switzerland, Austria and the Slovak Republic were contaminated to lower levels. 44% of Germany and 34% of the UK were similarly affected.
In the case of Chernobyl, 31 people died as a direct result of the accident; two died from blast effects and a further 29 firemen died as a result of acute radiation exposure (where acute refers to infrequent exposure over a short period of time) in the days which followed.
The Chernobyl Forum, a group of eight U.N. agencies, and the governments of Ukraine, Belarus and Russia, have estimated the death toll at only a few thousand as a result of the explosion. U.N. agencies have said some 4,000 people will die in total because of radiation exposure.
800,000 men risked their lives by exposing themselves to radiation in order to contain the situation. 25,000 of these have died and 70,000 are disabled. 20 % of those deaths were suicides
The environmental group Greenpeace places the eventual death toll at 93,000 cancer deaths worldwide. Greenpeace expects up to 60,000 cases of thyroid cancer from the incident
A 30-km (19-mile) exclusion zone is in place round the disaster site.
Around 97% of the radioactive material remains in a crumbling sarcophagus. A make-shift cover — the ‘Sarcophagus’ — was built in six months after the explosion. It covers the stricken reactor to protect the environment from radiation for at least 30 years.
The sarcophagus locked in 200 tons of radioactive corium, 30 tons of highly contaminated dust and 16 tons of uranium and plutonium
In 1992, Ukraine’s government held an international competition for proposals to replace the sarcophagus
On 17 September 2007 Vinci Construction Grands Projects and Bouygues Travaux Publics announced that they won the contract to build the New Safe Confinement as 50/50 partners of a French consortium named Novarka.
The New Safe Confinement (NSC or New Shelter) is a structure built to contain the remains of the No. 4 reactor unit at the Chernobyl Nuclear Power Plant. The structure also encloses the temporary “sarcophagus” built around the reactor immediately after the disaster.
According to a project official, construction completion will be delayed until May 2018 due to a contractor being unable to finish its works in time. The reason is the extremely high level of radiation, forcing workers to limit their presence at the site to a minimum.