According to the design cooling pools were intended for Spent Fuel Assemblies (SFA) temporary storage and storage of special items, irradiated in a reactor or being in contact with radioactive coolant (spent additional absorbers, control rods, internal monitoring sensors and other equipment). The water in the cooling pools ensures removal of residual heat from Spent Fuel Assemblies, as well as serves as biological protection against the ionizing radiation impact on the staff working in the Central Hall.
Since Units 1, 2, 3 are completely emptied from Spent Nuclear Fuel, including the damaged fuel, as well as taking into account the positive experience in operation of Unit 3 cooling pools for technological channels in the dry mode of special items storage shafts, it was considered possibility of emptying Units 1, 2, 3 cooling pools and storage of active special items in them without water filling, that is, cooling pools operation in dry mode of storage in shafts for special items.
Within the period from June to October of this year at Units 1, 2, 3 works on the cooling pools emptying were carried out, and above the cooling pools, containing highly active special items, protective coverings were assembled, providing biological protection against ionizing radiation.
Currently, Units 2 and 3 cooling pools are transferred in the mode of dry storage shafts for special items according to the relevant technical solutions agreed by SNRIU. The similar technical solution for Unit 1 is under development.
Cooling pools operation in the mode of dry storage shafts for special items will significantly reduce the cost for water chemistry and temperature maintenance in them, for Main building premises heating with a water-filled equipment in the winter, and will allow reducing the risks of the equipment damage in case of emergency situations in the heating systems of ChNPP industrial site during the winter.
After the work performance radiation situation in the Central Halls is within established limits.
Works related to the cooling pools emptying were performed by SSE Chernobyl NPP personnel.