Chernobyl

Chernobyl (in Ukrainian, Chornobyl), town, north-central Ukraine, located on the Pripyat River near the border with Belarus, approximately 130 km (80 mi) north of Kiev and 20 km (12 mi) from a nuclear power plant, which bears the city’s name. One of its reactors went out of control on April 26, 1986, and caused the world’s worst known reactor disaster to date. Population 10,237 (1993).

An improperly supervised experiment conducted with the water-cooling system turned off led to an uncontrolled reaction, which in turn caused a steam explosion. The reactor’s protective covering was blown off, and approximately 100 million curies of radionuclides were released into the atmosphere. Some of the radiation spread across northern Europe and into Britain. Statements from the Soviet Union, of which Ukraine was then part, indicated that 31 people died as a result of the accident, but the number of radiation-caused deaths, as yet unknown, is expected to be much greater. More than 100,000 people were evacuated from areas around the reactor site, and Chernobyl and some other settled regions remained unoccupied one year later.

Officials who were responsible for the reactor were tried in 1987, and six of them were sent to labour camps. The other three Chernobyl reactors were returned to operation that same year, and the immediate evacuation zone of the disaster was later declared a national park. In 1991 the government pledged to close down the entire Chernobyl plant, but energy demands delayed the move. In mid-1994 Western nations developed an aid package designed to ensure the closure of the unsafe plant, and in late 1995 the Ukrainian government and the G-7 group of the world’s richest countries signed a Memorandum of Understanding, setting out conditions and provisions for the closure of the remaining reactors. The agreement was ratified in April 1996. The decommissioning of the plant was, however, delayed as a dispute over a compensation package for Ukraine continued and efforts were made in 1998 and 1999 to stabilize the affected reactor.

Specifically reservations arose over the stability of the “sarcophagus”, the massive concrete and steel shell constructed over the defective reactor in the months following the accident. Although the structure was designed to last 30 years, cracks, holes, and other weaknesses have been detected in it, causing some experts to fear the release of radioactive dust. Research has also shown that the design of the sarcophagus does not make any allowances for earthquake stresses.

The plant was finally shut down on December 15, 2000. Its workers, most of whom had stayed on at the plant after the accident, continued to face an uncertain future, as few social, economic, and living provisions had been made for the Chernobyl community. More than a decade after the Chernobyl accident, restrictions on local habitation and agriculture in the area remain in place. The medical consequences of the accident were severely underestimated and, although long-term effects on the health of the local population cannot yet be fully gauged, genetic damage is feared. Other areas of health concern are the increase in psychological disorders and thyroid cancer, particularly in children. Studies in 2001 indicated that almost 2,000 thyroid cancer occurrences had been confirmed as the result of the accident, with many more expected to emerge; the Chernobyl disaster has been followed by a record number of confirmed cancers resulting from a single source.