Technical management on the Chernobyl site, status and future of the Sarcophagus

One of the main problems among the many following the CHERNOBYL power station accident was that of preserving the nuclear fuel remaining in the fourth destroyed reactor. Its quantity is estimated as 96% of the total quantity located in the fourth reactor before the accident, in other words about 180 Tonnes of uranium, about 400 kg of plutonium-239, about 170 kg of plutonium-240 and a significant quantity of transuranic elements. About 70% of accumulated cesium radioelements are also stored in the reactor building. Work carried out to ensure its safety took place in several stages: - Action during the active phase of the accident during which millions of curies were projected outside the destroyed reactor daily. This phase lasted between April 26 and May 5 1986. On May 6, the radioactivity dropped by a factor of hundreds or thousands and has not been renewed since. - The second stage is that of building the protection (or sarcophagus) for Chernobyl unit 4 (June - November 1986). Attention was then turned towards the implementation of a safety inspection of the fuel inside the protection under safe conditions, ensuring that it would not react on the environmental milieu (December 1986 to the present time). In the future, we will need to enter a final stage of the works. We will need to create a completely safe, long duration storage for the destroyed fuel