On 26 April 1986, the Chernobyl nuclear power plant’s number four reactor exploded, sending a radioactive cloud across much of Europe. Following the explosion, radioactivity with an intensity equivalent to 500 of the bombs that destroyed Hiroshima at the end of World War II was measured in the atmosphere.
In 2005, the International Atomic Energy Agency (IAEA) and World Health Organization (WHO) reported that 56 people died directly from the incident, mainly accident workers. They estimated another 4,000 deaths among workers and local residents.
According to unofficial statistics, though, at least 15,000 people died as a direct result of the explosion.
The power station is still seen by critics as a time bomb, and work was carried out ever since to try and make the site safe.
The Ukrainian Government initiated a long-term plan to protect the Chernobyl shelter from the radiation.
The work that was carried out was considered unsatisfactory by the West. Chernobyl still operated for some time afterwards (there was not enough generating capacity in Ukraine for its closure) and countless, more minor, incidents occurred since 1986.
After a 1991 fire in Reactor 2, this reactor was taken offline and decommissioned in 1996. Reactor 3 was switched off in 2000 to close the plant. In early 2002, the European Commission paid the first instalment of its promised €40m additional Shelter Fund. The fund was paid in four instalments from 2001-2004. It helped to support the decommissioning work at the site.
Following the 1986 accident, the number four reactor at Chernobyl was encased in a giant concrete ‘sarcophagus’ to prevent further leakage of radioactive material. Hundreds of thousands of mobilised soldiers and civilian experts constructed the sarcophagus above the destroyed reactor, and the plant was re-opened in late 1986. A huge fire in the second reactor led to its closure in 1991, and in 1996, the number one reactor was shut down as it had reached the end of its life-span.
The sarcophagus built in 1986 was considered to be unstable and needed further repair work. In December 2000, the US promised to contribute the largest G7 amount to repair the sarcophagus. A waste management facility began construction in 2001 for the treatment of fuel and other wastes from decommissioned units one-three. A stabilising steel structure was extended in December 2006 to spread some of the load on the walls damaged by the explosion.
The fuel mass at the reactor has also been enclosed in EKOR, a radiation-resistant material developed by Eurotech Ltd of the UK. The material was applied during March 2000 and is maintaining an isolation coating and seal of the pile, preventing further dusting and leaching of contamination to the environment.
After two months, EKOR exceeded the longevity of all previously applied materials, which degraded rapidly in the severe-radiation environment and lost isolation effectiveness.
The EKOR-encapsulated fuel pile has radiation readings in the range of 1,000 rads on contact, although EKOR has been laboratory tested to an accumulated dose of 10 gigarads without loss of physical properties.
In June 1999, ChNPP and a consortium led by Framatone signed a contract to build a facility to store spent fuel. In August 1999, ChNPP signed an agreement with a consortium led by Belgatom for a Liquid Radwaste Treatment Plant (LRTP). A steel casing is now being built over the reactor. French firm Novarka is building the casing, costing $1.4bn. After that, Reactor 4 will be dismantled.
Construction of the casing is expected to be completed by 2012. Novarka would build an arch-shaped structure measuring 190m wide and 200m long, covering the existing containment structure, which is above the reactor and radioactive fuel. A separate deal has been signed with the US firm Holtec to build the storage facility, to store the nuclear waste produced by Chernobyl Nuclear Plant.
On 7 January 2010, the Ukrainian Government passed a state law to transform the Chernobyl shelter facility into an environmentally safe system in order to protect the surroundings from radiation. The programme will be executed in four stages.
In the first stage, nuclear fuel will be moved to a storage facility, which will be completed by 2013. In the second stage, which will be completed by 2025, all the reactors will be deactivated. The third stage involves maintaining the reactors until radiation drops to an acceptable level and is envisaged to be completed by 2045. The fourth and the final stage involves dismantling the reactors and clearing the site, which is expected to be completed by 2065.
The state law programme is being financed by the European Bank for Reconstruction and Development and other international donors.
In addition, a seminar was conducted by IAEA to discuss the decommissioning of the cooling pond, which was highly contaminated after the explosion.
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