ux, temperature, heat flux, as well as the concentrations of hydrogen, carbon monoxide and water vapor in the air. Other sensors monitor the mechanical stability of the structure and vibration of major components. All these sensors are under computer control. Systems designed to balance any changing conditions have also been activated. These include the injection of chemicals to prevent nuclear leakage and to pump excess water leaking into the sarcophagus.An enormous effort was required to mount the clean-up operation; decontaminating ground and buildings, enclosing the damaged reactor and building the Sarcophagus was a formidable task, and it is impressive that so much was achieved so quickly. At that time the emphasis was placed on confinement as rapidly as possible. Consequently, a structure that would effectively be permanent was not built and the Sarcophagus should rather be seen as a provisional barrier until a more permanent solution for the elimination of the destroyed reactor and the safe disposal of highly radioactive materials. In these conditions, to maintain the existing structure for the next several decades pose very significant engineering problems. Studies are currently underway to solve this problem.Nine years after its completion, the sarcophagus, although still generally sound, raises concerns for its long-term stability. Some supports for the enclosure are the original Unit 4 building structures, which may be in poor condition following the explosions and fire, and their failure could cause the roof to collapse. This situation is added upon by the corrosion of internal metallic structures due to the high humidity of the Sarcophagus. This humidity was produced by the penetration of large quantities of rainwater through the numerous cracks that were present on the roof and were only recently repaired.The structure is not designed to withstand earthquakes or tornadoes. There is also considerable uncertainty on the ...
