Originally, it was planned that a total of six units of the Soviet RBMK-1000 reactor type were to be built at the Chernobyl site. The RBMK is a graphite-moderated pressure tube boiling water reactor. International analyses showed their safety deficits both in design and operation.

A recap

The Chernobyl nuclear power plant is located in the Ukraine right next to the river Pripjat. At the time of the accident, four reactor units of the type RMBK-1000 were in operation, each with a capacity of 1000 MW.
The explosion of reactor no. 4 on 26 April 1986 and the subsequent fire in the reactor core led to a substantial release of radioactive material into the environment.

After the accident, the so-.called Sarcophagus was built around the destroyed reactor unit at great haste in 1986. It was meant to limit the release of radioactive materials into the environment and safely confine the radioactive materials inside the destroyed unit.

The G7 and the Ukraine have agreed upon an action plan to support the closure of the Chernobyl NPP (MoU Chernobyl). Further actions include the Shelter Implementation Plan and the French-German Initiative (FGI). The bilateral activities are summarised in the bilateral Chernobyl Action Programme (TAP).