n the Soviet republics were frozen. Public opinion was directed against nuclear power plants. Some plants were even shut down, but have now been reactivated. The accident has also initiated an international activity in the area of nuclear safety and nuclear emergency planning. Many countries started a development of decision support systems for nuclear accident cases.The way in which Soviet leaders have dealt with the situation is very unsettling. In the aftermath of the catastrophe several designs to encase the damaged reactor were reviewed. The option that was selected included the construction of a massive structure in concrete and steel that used what remained of the reactor walls as support. Its construction is considered one of the most complicated building works in the world. In charge of building the tomb was Construction Department No. 605. They ran into many problems while constructing the massive concrete and steel shell. Concrete blocks for the tomb were pieced together far from the reactor itself, and the roads entering the facilities were not accommodated for such loads, which made it difficult for the drivers. Once the blocks were delivered, the workers needed to put them in place. Each weighed several dozen tons so eventually crane operators had to perform this task.This outer protective wall, 28 stories high, is placed around the perimeter and other walls connected to the Unit 3 reactor. A steel roof then completed the structure. The destroyed reactor was entombed in a 300,000-ton concrete structure known as the "shelter" or "envelope." In conditions of high radioactivity the mammoth task was completed in seven months, in November 1986. The site around the plant had then been announced safe for about the next thirty years. However today the sarcophagus is cracked and crumbling. Some of these cracks are as large as a garage door.Multiple sensors were placed to monitor levels of gamma radiation, neutron fl...
