The Chernobyl disaster — 30 years later

The worst nuclear disaster in history happened 30 years ago at the nuclear power plant at Chernobyl, Ukraine.

On 26 April 1986 engineers carried out a safety test in Block 4 of the reactor. A human error and the unsafe design of the building set off a fire and caused an explosion. The core of the reactor melted and huge amounts of radioactivity were released into the atmosphere.

The disaster was not made public by Soviet authorities until two days later. It was only after radioactive clouds started spreading across Sweden that government officials announced what had happened.

According to Soviet officials, 30 people died in the explosion and from radiation sickness in the days and weeks that followed. The World Health Organization estimates that since the accident 9,000 people have died of cancer and other illnesses. Greenpeace places the number of deaths at 90,000.

Towns and villages in the disaster area were evacuated. 350,000 people had to be resettled and can never come back to their original homes. A thousand square miles (2600 square km) in the Ukraine and Belarus will stay off limits for decades to come.

In the weeks after the Chernobyl catastrophe, half a million people were brought in from around the Soviet Union to clean up the site. The countryside around the reactor was closed off and nobody was allowed to get near the damaged reactor. A sarcophagus was built over the exploded building to keep more radioactive waste from escaping into the atmosphere.

Currently, a new containment is being built because nuclear experts fear that the life of the old sarcophagus may be coming to an end. A shelter in the form of an arch will cover the destroyed building. The $ 2 billion-dollar structure is expected to prevent radiation from getting out for at least a hundred years.

Ukraine officials held memorial ceremonies and laid wreaths to mark the 30th anniversary of the disaster. Former Soviet leader Mikhail Gorbachev said that the Chernobyl disaster was one of the factors that led to the Soviet Union's collapse in 1991. Even 30 years later the disaster is still in the minds the people who once lived in the area.

Internet: <www.english-online.at>.

Based on the text, judge th following item.

“Currently” can, without changing its meaning, be replaced for Heretofore.