Built in the aftermath of the 1986 Chernobyl disaster, the sarcophagus was designed to limit radioactive contamination of the environment by encasing the most dangerous area and protecting it from climate exposure.

The entire construction process consisted of eight stages: More than 400,000 cubic metres (14,000,000 cu ft) of concrete and 7,300 tonnes of metal framework were used during the erection of the sarcophagus.

[5] On 11 October 1986, the Soviet Governmental Commission accepted a report entitled: "Conclusion on Reliability and Durability of a Covering Constructions and Radiation Safety of Chernobyl NPP Unit 4 Reactor Compartment".

The "Mammoth Beam" that supports the roof of the shelter rests partly on the structurally unsound west wall of the reactor building that was damaged by the accident.

The DSSS is a yellow steel object that has been placed next to the wrecked reactor; it is 63 meters (207 ft) tall and has a series of cantilevers that extend through the western buttress wall, and is intended to stabilize the sarcophagus.

[citation needed] A further threat to the shelter is the steel and concrete slab that formed the upper biological shield (UBS), situated above the reactor prior to the accident.

[citation needed] This concrete slab was thrown upwards by the explosion in the reactor core and now rests at approximately 15° from vertical.

In 1998, with the help of the European Bank for Reconstruction and Development, a conservation programme was completed that included securing the roof beams from collapsing.