Common Concerns

Photo: Soviet Authorities

Photo: World Nuclear News

Explosions occurred at Chernobyl Nuclear Power Plant in the former Union of Soviet Socialist Republics (USSR) on 26 April 1986. The large amount of radioactivity subsequently released affected areas as far as several hundred kilometres away from the plant. This was the most serious accident in the history of the nuclear industry.

The accident occurred at Unit 4 of the plant during the preparation of a planned test. In order to fulfill the requirements of the test, certain safety systems were deliberately disabled and the reactor was run in an unstable condition at low power for several hours. These steps resulted in a steam explosion within the reactor. This in turn caused reactor damage, a fire at the reactor building and the release of a large amount of radioactivity. Within a few weeks, the accident had caused the deaths of 30 workers and radiation injuries to over a hundred others. Some 335,000 people were evacuated. At present, apart from approximately 7,000 cases of thyroid cancer recorded, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has found no other health effects attributable to the resultant radiation exposure.

After the incident, The World Association of Nuclear Operators (WANO) was established in 1989 to enhance the exchange of best practices and safer operation of nuclear power stations among members of the nuclear industry. The International Atomic Energy Agency (IAEA) and Nuclear Energy Agency of Organisation for Economic Co-operation and Development (OECD/NEA) also set up the International Nuclear and Radiological Event Scale (INES) to enhance external communications during nuclear incidents.

In 2012, the construction of a giant safe confinement structure for protecting the ruined reactor has been started. The structure is designed to last at least 100 years and the assembly and installation work is expected to complete by 2015.