How many reactors did Chernobyl have?

The Chernobyl Power Complex, located approximately 130 kilometres north of Kyiv, Ukraine, and approximately 20 kilometres south of the border with Belarus, was comprised of four nuclear reactors of the RBMK-1000 design (see information page on RBMK Reactors).

Units 1 and 2 were built between 1970 and 1977, and units 3 and 4 of the same design were finished in 1983. At the time of the catastrophe, two more RBMK reactors were being built on the site.

To the southeast of the facility, a 22-square-kilometre artificial lake was built beside the Pripyat River, a branch of the Dniepr, to provide cooling water for the reactors.

Chernobyl, a town with a population of 12,500 people, is situated about 15 kilometres southeast of the complex. At the time of the catastrophe, the total population within a 30-kilometre radius of the power plant ranged between 115,000 and 135,000.

The Chernobyl disaster in 1986 was caused by a defective reactor design that was operated by inexperienced personnel. The resulting steam explosion and fires spilt at least 5% of the nuclear reactor core into the environment, causing radioactive elements to be deposited in numerous parts of Europe.

Two Chernobyl plant workers died on the night of the disaster as a result of the explosion, and a further 28 people died within a few weeks as a result of acute radiation sickness.