26 April 2006 - Events were held in Ukraine today to mark the 20th anniversary of the world's worst nuclear disaster at the Chernobyl power plant. President Viktor Yushchenko will visit the site later in the day and will meet some of the people who worked at the plant and those who risked their lives to deal with the accident.

The explosion occurred on 26 April 1986 and a tolling of church bells followed by a minutes silence was observed in Kiev at 0123 local time today marking the time when the alarm was set off. President Yushchenko laid a wreath to remember those who were sent to deal with the accident and to the many who have since been affected.

A monument to victims is due to be unveiled, and parliament is holding a special hearing into the disaster.

Hundreds of people, each bearing a candle and some with red carnations, filed slowly through the streets of Slavutych, the town built to house the Chernobyl plant's workers.

The explosion in one of the four reactors at the Chernobyl nuclear plant resulted in the release of radioactive fallout 100 times greater than that released by the bombs dropped on Nagasaki and Hiroshima. Staff at the Soviet designed plant were undertaking an experiment which went wrong and since emergency shutdown systems had been disabled, they had no way of preventing the overheating and resultant explosion.

The number of victims of the disaster is a matter of dispute. Official UN figures predicted up to 9000 Chernobyl-related cancer deaths. But a Greenpeace report released last week estimated a figure of 93 000. Greenpeace said other illnesses could bring the toll up to 200 000.

Soviet authorities took two days to inform the world and their own people. They then launched feverish clean-up and reconstruction efforts culminating in the hasty construction of a concrete casing to entomb the wrecked reactor.
A restricted area with a radius of 30km (19 miles) remains in force around the destroyed nuclear reactor, which is encased in concrete. _The encasement is crumbling and there are fears that more radioactive material will be released. Plans are in place to build a larger £600m ($1bn) replacement shelter designed to last 100 years.

The accident at Chernobyl has cast a cloud over the nuclear power industry ever since and the effects are still being felt across Europe in terms of environmental damage and health concerns.

Mohamed ElBaradei, head of the International Atomic Energy Agency, said the anniversary was a reminder of the need for a common approach to nuclear safety, especially as many countries are planning to build new reactors.